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MOTION AND TIME TECHNIQUE
IN THE MANUFACTURE OF MILK
POWDER WITH A SPRAY DRYER

Thesis Ior The Degree OT M. S.
MICHIGAN STATE UNIVERSITY
Chaturbhuj B. Tewary

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This is to certify that the

thesis entitled

Motion and Tine hehniquo
1n the Manufacture of Milk
Povdsr with 1 Spray Dry-1".

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presented by

has been accepted towards fulfillment
of the requirements for

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I B R A R Y
Michigan State
University

”i:

e

MUI‘ION AND TIME TECHNIQUE
IN THE
MANUFACTURE OF MILK PMER

NITH A SPRAY DRYER

BY

CHATURBHUJ B . TEWARY

A THESIS
Submitted to the College of Agriculture of the Michigan State University
of Agriculture and Applied Science in partial fulfillment of
the requirements for the degree of

MASTER OF SCIENCE

Department of Agricultural Engineering

Approved by kW“ W

JUNE 1960

AN AC I31 OWLEDGEI‘JEL‘JT

In presenting this volume, the author desires to
‘express his gratefulness for the generous assistance
he has received from Dr. A.W. Farrall, head of the
Department of Agricultural Engineering, who made pro—
vision for the necessary funds to undertake the study.

The author is very much indebted to Dr. C.W. Hall,
Professor of Agricultural Engineering, for many months
of valuable counsel, suggestions and advice in complet-
ing the study. The author wishes to express his thanks
to Dr. Hall particularly for making special arrangements
for the facilities required for completion of the study
in the shortest possible time and for giving encourage-
ment from time to time.

The author wishes especially to eXgress his
appreciation of valuable teaching and helpful guidance
received from Dr. Dale Jones, Professor of Industrial
Engineering.

VThe author is indebted also to the many individuals
and a number of Dairy factories and firms in the field
of dairy equipment and supplies for their generous
cooperation in providing immense facilities and
information required for completion of this study.
Appreciation is also expressed to members of the fa—

culty of the Department of Dairy.

— iii —

In the last, but not in the least, the author
can not remain without thanking my beloved wife
-Shreemati Kanti Devi who enabled continuation of
studies in the U.S.A. by her skillful handling of

responsibilities at home while working on the Thesis.

-iv-

CCNTENTS

Title Page ................................... 1
Acknowledgement .............................. ii
Contents .........:........................... iv
List of Figures and Tables ................... v,vi
Importance ................................... 1
Objective .................................... 8
Review of Literature ......................... 9
Spray Drying Installations ................... 16
Procedure for Study— Methods employed ........ 24
Results and Discussions ...................... 34

(a) Standard Times

(b) Labor Requirements

(0) Saving of Cost

(d) Check List
Conclusions .................................. 70

Slime-v1?!.000.00.00...00......OOOOOOOOOOOOOOOOO 70

References 0.0.0....O...OOOOOOOOOOOOOOOOOOO... 88

Iv'

LIST OF FIGURES

Page

Figure 1 Relationship between annual volume of production and 23
dry milk output per hour of labor.

Figure 2 Man-machine operation of pan as observed for normal 46
working conditions.

Figure 3 Man—machine Operation for spray dryer as observed 47
for normal working conditions. '

Figure 4 Cost of Spray drying skim milk with several 59
combinations at various volumes.

Figure 5 Relationship between volume of dry milk produced 61
an average cost per pound.

Appendix A (a) Floor plan for Plant A 72

(b) Floor plan for Plant B

(c) Floor plan for Plant C

Table

Table

Table

Table

Table

Table

Table

Table

Table

Table

10

LIST OF TABLES

Production of dry milk products in the
United States.

Relationship between annual dry milk output
per plant and labor cost.

Elemental times for operation of vacuum pan.
Summary of pan Operations.

Elemental times for operation of spray dryer.
Summary of dryer operations. .

Elemental times for operation of packaging of
powder in paper bags.

Summary of powder packaging in paper bags.

Summary of standard times of manual operations.

Relationship between dry milk output and labor
costs of 18 drying plants.

Page

21

34

35

36

38

39

41

53

58

ILIPORTAII CE

Dried milk, similar to condensed milk, is a form of concen—
trated milk. Each form of fluid milk product and fluid milk
by-product lends itself to conversion to the powder form. Thus,
to-day we have dried whole milk, dried cream, dried skim milk,
dried buttermilk, dried whey, dried ice cream mix, dried malted
milk and dried sweetened condensed milk.//

In most dairy countries volume production of milk powder
began with the drying, not of whole milk but of skim milk. This
has been true especially of countries that convert a large
portion of their milk production to butter and sweet_market cream,
thus being confronted with the problem of finding a profitable
market for large volumes of surplus skim milk. The reason for
volume production of dried skim milk is obviously an economic one.
But there appears to be only one answer to the problem of pro-
fitable exploitation of the creamery skim milk and that is to
market it in suitable form for human consumption or animal
consumption.

With the advent of dried skim milk supplied not only as such
to the kitchen of the consumer, but especially to the prepared
food factories, (such as for the manufacture of ice cream mix,
candy, confections, milk chocolate, for bread making, as a
constituent of sausage, in prepred soups, etc.), hundreds of
millihns of pounds of surplus fluid skim milk are annually
diverted from channels of complete waste and financial loss and

turned into channels for human nutrition, profitable returns,

and promotion of public health. Thus, the obvious features of the

economy of dried skim powder appear as follows:-

(i) Reduction to minimum bulk to facilitate economical transpor-
tation to all parts of the world.

(ii) Dependable keeping quality of the finished product.

(iii) Optimum conservation of the natural properties that are
characteristics of fresh milk, during storage.

(iv) No refrigeration necessary for storage and long transport.

(v) Use in manufacture of several pregired food stuffs like
ice cream, candy, confections, milk chocolate, etc.

(vi) The economic utilization of surplus adding flexibility to
the operation of the plant and resulting in a higher profit
at the Same time.

(vii) Better source of serving the community with reconstituted
milk from period of plenty to the period of lean supply as
well as from the areas of plenty to the areas of scarcity.

In sharp contrast to the phenomenal production of dried

skim milk, the annual output of dried whole milk has been limited,

and prior to World War II it appeared relatively static. Foremost

among the volume retarding factors has been the problem of the
dependable keeping quality. Dried whole milk is subject to
oxidation of the milk fat, accompanied by quality - destroying
undesirable flavor. Dried skim milk is practically free from this
danger. Extensive experimental research was necessary, therefore,

to establish means of preventing costly age spoilage of dried

whole milk, sufficiently dependable to justify upon embarkation
upon a large scale production of this important food product.

Due to the food urgency of World War II, these efforts in the
interest of quality improvement were redoubled. This has resulted
in improved methods of manufacture and packaging, methods that
are proving effective in delaying or preventing damaging fat
oxidation. These accomplishments have definitely diminished the
risk of storare and increased the volume of the manufacture of
dried whole milk. Thus, from a production of 30 million pounds in
the year 1940 it increased to 217 million pounds in 1945.

In the presence of the marked develoument that has been made
within recent years, in volume of production, and in the per—
fection of flavor, keeping quality and solubility of dried whole
milk, and of the properties of its reconstituted products, it is
interesting to note the early verdict of the eminent German dairy
Scientist, Dr. W. Fleischmann (Hunziker, 1949) of the University
of Gottingen, on the future possibilities of whole milk powder.
This investigator commented upon the poor keeping quality ,
quality, unpalatibility, insolubility, and denatured condition of
the protein of dried whole milk made in the latter half of the
nineteenth century by the firm Dalsom, Blatchford and Harris, in
their factory near New York City. As a result of this failure,
Fleischmann reached the following conclusions: (Translated from
the German by Mr. Hunziker). “

"As a result of this failure, the question whether it is

possible to produce a marketable product worthy of the name milk
by dehydrating milk and reconstituting the dried mass, is thus
answered conclusively and finally for all timefi.

World War II and the early postwar years saw a rapid shift to
the selling of whole milk by farmers rather than selling of farm
separated cream. This shift was greatly accelerated by the relati-
vely favorable prices paid for non—fat dry milk solids in that
period. To process the resulting increase in the supply of milk,

a number of new centralized drying plants were built and production
facilities at the existing plants were expanded. Many marketing
problems have accompanied this rapid growth in the dry milk industry.
They have intensified since the close of the Korean war. The supply
of non-fat dry milk solids has greatly exceeded the demand in recent
years, and much of the output has been purchased by the government
under the price support program. Under this surplus situation the
difference between cost and prices received for dried milk have
narrowed.

In view of these conditions Operators of milk drying plants
have shown an increased interest in possibilities of decreasing
costs in processing. Increased efficiency and lower costs should
enable the plants to return to the farmer a higher percentage of
the price which consumers pay for dry milk products.

In the United States the production of only non-fat dry milk
solids has been increasing rapidly since 1951. Production in 1955

set a new record high of 1.48 billion pounds.

Table 1 shows the large increases in production of non—fat dry

milk from 1947 to 1955 (U.S.D.A., 1957).

TABLE 1. - Production of dry milk products in United States,

 

1000 pounds 1947—1955.
Year Type of Dryer Total Whole milk Dry butter milk
Spray Roller

1947 418,704 259,237 677,941 164,888 45,437
1948 436,071 245,461 681,532 170,087 418,39
1949 627,942 306,992 934,934 1259541 ‘9,359
1950 623,967 257,111 881,078 124,986 48,668
1951 546,387 156,089 702,476 131,017 45,467
1952 665,076 198,144 863,220 101,732 47,067
1953 971,578 242,196 1,213,774 104,352 57,424
1954- 1.158,537 243,537 1,402,374 93,874 56,348
1955 1,282,000 202,600 1,484,600 103,220 58,350

In 1953, the three leading States, Wisconsin, kinnesota and
New York produced respectively 28, 21 and 11 per cent for a combined
total of 60 percent of the total United States production of non-
fat dry milk solids.

The rate of utiliZation of skim milk for human food has in-
creased from 51 percent in 1924 to 74 percent in 1952 and there

has been a continuing trend away from farm separated cream;

Dried milk in India. — In India the productivity of dairy cattle

 

increases and decreases according to change of climatic conditions
and growth of pasture land after rainy season resulting concen-
tration of cattle at different places. Host of the dairy cattle
feed on the natural growth and abundance of grass land and
agricultural by—products. Because of this concentration, the milk
production in such areas increas s greatly and sells at a lower
rate in absence of sufficient transport facilities to the areas of
greater demand. In addition, with the recent agricultural develop-
ment and cattle improvement program launched in the Five-Year Plans,
the productivity of milk is likely to increase. The above described
surplus areas will have the increasing problem of handling the
surplus milk thus produced to points of utilization. Since the
distribution of milk from surplus rural areas to urban areas still
remains a problem due to insufficient facilities of transport, it
appears that the immediate solution for useful utilization of milk
at the surplus pockets throughout the country is to convert it to
products like butter, ghee and skim p wder. These three products
can not only be transported easily but will immediately add to the
economy of farmers and create a scope for development of dairy
cattle and dairy industries in the country. The skim milk powder
will be easily reconstituted with whole milk usually having 6 to to
percent butterfat. This reconstituted milk if standardized to

3 percent butterfat will not only result in increased quantity

but will be much leSs expensive compared to whole milk of high

percentage of butterfat, readily enabling more extensive use of
Milk.

It is understood that this idea of making useful and
economical utilization of milk from various surplus pockets in
India for benefit of maximum pOpulatien, has been receiving the
active consideration of the government and that a number of
creameries and milk drying plants will soon be set up. At present
a huge quantity of milk powder is being imported in India and

the requirement is increasing day by day.

4.

OBJECTIVES

To determine time standards for the required elements of
drying plant operations.

To recommend conditions pertinent to efficient Operation.
To recommend improvements in the layout of the working
place and material handling for efficient Operation, in
reference to plants investigated in study.

To suggest means of inbreasing the effectiveness of
effort through application of principles of motion

economy.

REVIEW OF LITERATURE

fiction and time techniques. - The science Of motion and time study
has been widely practised throughout the world for the last 70
years. In about 1881 when Taylor pioneered this science, it was
not realized that his words of wisdom would in later years meet
with such universal acceptance by all of the major industries of
the world. Except for the initiative and ambition of those who
would mak any nation the greatest and most productive industrial
nation, motion and time study might never have been recognized as
one of the finest tools of management. The largest and strongest
labor unions in mass production industries have also recognized
the value of motion and time studies as through the years they
have gradually developed an acceptance of this art as an accurate
technique for establishing standard of performance for man and
machine. Industries have used motion and time studies extensirely
in analysis of their processing and assembly Operations. It must
be acknowledged that use of this valuable tool has contributed to
ever—increasing efficiency, which in turn has produced better
merchandise at lower cost, and at the same time has provided a
more equitable means of pay.

The dairy industry has been somewhat tardy in applying this
valuable tool of management. Only in recent years have several
dairv companies throughout this country seen the Opportunities

afforded by use of motion and time study techniques in analysis Of

_ 10 _

processing, clean up and delivery Operations. The results of these
studies have reflected improvements in already existing plants and
have aided immeasurably in design and layout Of new plants, in
determining product cost, and in improving methods.

The questions in the minds of the typical dairy plant Operator
when contemplating the need for time studies in his plant are many.
What will the time studies accomplish? Will such a study help in
determination of accurate costs? Will information resulting from a
time study help in control of labor cost, and if so how? Is time
study only for the plant processing half a million pounds a day, or
can it be used by small plants? What is the reaction of the plant
worker with respect to time studies? Will I be able to do better
job of running my business than I am now doing? The answers to such
questions are not categorical but are dependent upon many factors
Of personnel and complexity of plant Operation.

One unfortunate prejudice among industrial workers is that
time and motion study is a means applied to exploit the labor.

Time and motion prOperly used is not a means of exploiting the
worker. It is a means for exploiting his capacity to work and in the
benefits of which he is one of the largest sharers.

No matter how uncertain the management of a plant may be, one
thing is certain, namely, that it can still increase its profit and
production by reorganizing the work according to the principles of
time and motion study.

It is a well known fact that the output of work to be expected

from any two of the men working in the plant may be as varied as
the quantity of milk given by the highest and the lowest production
cows in a herd of dairy farm. Why whould one man do more work in a
given hour than another? Is it that higher producing worker is
stronger? Quicker? Defter? Better trained? Has better tools?

Likes his job? Likes his boss? Or a combination of all these
things and many more? Whatever may be the reason, management needs
now more than ever to look closely at the work and the workman.
Work is a vague term; hard work is more vague. It is only compa—
ratively recent that scientists have been trying to measure 'work'
in a plant and even so a 'worx unit' differs from one part of the
country to another, from one country to another. A pound of work
in U.S.A. may not be the same as a pound of work in India because
the working conditions in the two countries are different.
Nevertheless, it is easy enough to compare the work done by two
men in the same plant by measurement of work performed by each

man even with altered equipment and their layout plans.

Among the various forms of cost are reduction in activities
in a processing plant, work simplification, linear programming,'
operations research, budgetary control and time study. The
determination of time standard by a method of time and motion
study, for each operation in the plant at its maximum efficiency,
has been felt to be of paramount importance in improving plant
operations.

Time study can be a precise, expert measuring technique for

...12_

labor analysis, but the term "time study" can easily lead to a
confusion of terms. Stopwatch study, motion picture analysis,
micro motion analysis, simultaneous motion study, synthetic
standard deveIOpment and standard data are all related to the
study of time.

The use of time and motion study in milk plant operation is
so new that very little reference to it can be found in the
literature. No reference was found specifically on motion and
time study in spray drying of-milk.

Therefore most of the references cited have been taken from
other industries that have more or less similar operations. The
milk industry has always tried to practice some work simplification,
although it was never given exactly this methods engineering
nomenclature. Some literature on milk drying is available but

dealing primarily with the costs involved.

Time and motion study applicationsgin allied industries.- Applica-
tion of time and motion analysis to non-reuztitive operations was
demonstrated by Sadoff (1944). He made time and motion studies of
all the clean-up and maintenance operations at the large Swift and
Company meat packing plant in Chicago. Six senior time study men
devoted three years to this study. They were able to simplify the
Operations and establish s andard times for each operation.

Gobb (1937) also established standard times for truckers and

sweepers and out these men on an incentive pay plan which reduced

- 13 _

the man power required from 19 to 11 men.

Emmons (1937) applied time and motion analysis to the
janitors in a factory building, and was able to establish a
schedule of Operations that resulted in large savings.

In his work with time and motion applications to job order
shops, Tidball (1936) proved that it was possible to have time
standards for special order shops.

The continuous flov processes of the chemical industries
have much in common with milk plant Operation. Von Pechmann (1943)
and Rossmoore and Aries (1947) applied time and motion analysis
to these industries with great succes. They reported savings in
time up to 34 percent on some operations.

In the liquor distilleries, a large amount of time is spent
in bottling and clean—up operations much like milk plant operations.
Yliseinger (1941) applied time and motion studies to these
operations and reports savings as high as 33 percent.

All Operations in the food industry have much in common. The
use Of time and motion studies in food-plants other than dairy
plants has become quite common in recent years. Engel (1940) reports
some very interesting savings made in an English walnut food
factory. Kadler (1950) applied time and motion study to cannin
plant Operations with a great deal of succes. He lists some of
the results of these studies as:

1. Improved schedules.

2. Predoterminatien of job requirements.

_ 14 _

3. Checks on worker efficiency.

4. Determination of best methods.

Mundel (1944) has devoted a large amount of time to applica—
tion of time and motion study to farm operations such as doing

farm chores. These Operations in the past have taken a large

Ck

amount Of the farmers time. In some cases Mundel was able 0
reduce the time required by 50 percent.

Another interesting time and motion application by Mundel
was on the hand peeling Of tomatoes in a canning factory. By the
use of micromotion camera studies, he w s able to effect large
savings in this Operation.

That time and motion study has many uses other than rate
setting was brought out by Stearns (1945) when he explained to
the plant managers the use of time and motion study by controlliig
schedules, man power requirements, and methods of Operation.

Te‘anes (1937) made a study of the walking reouired in a
factory packing department. By the use of time and motion analysis
he was able to reduce the walking required per man in an 8 hour
day from 12,000 feet to 1800 feet, with a resulting saving in

labor of over 30 percent.

Snecific time and motion applications in the dairy industry. - Pro—

 

bably the most extensive use of time and motion study in the
dairy industry has been made by H.P. Hood and Sons Company. This

dairy firm has established a full time methods engineering and

work simplification department. This department has been in
operation for more than 8 years, and during this time they have
been able by the use Of time and motion analysis to reduce their
operation time considerably.

Dunlop (1949 a) explained his method Of training personnel
in work simplification by the use of company s hools.

Pelling (1940) reported the use of time and motion analysis
applied to wrapping cheese in an Australian cheese factory. He
saved 2500 dollars yearly by an improved method.

Llorrow (1947) applied time and motion study to the retail
delivery of milk with good results.

The use of time and motion study in a British milk bottling
plant was discussed by Proctor (1949) in a paper presented at the

1949 World's Dairy Congress.

_ 16 -
SPRAY DRYING INSTALLATIONS

Over the last several years operating problems in dairy plants
have changed considerably. Modern, high Speed, automatic equipment
is available now as never before. There has been a significant
change in the last ten years in the type Of equipment and processing
Of products.

The capacity Of the various pieces Of equipment used in the
plants is selected to allow the equipment combination, as a unit,
to operate as closely as possible to the hourly capacity. The
spray dryer, the size of which is determined by plant volume, is
the key piece Of equipment in this combination. The dryer capacity
is determined by evaporator size, heater size and boiler size.

Even though equipment is selected that will provide minimum cost

at present, excess capacity may exist in a plant because it is not
in operation 24 hours a day. However, this ex ess capacity evists
in all pieces of equipment in the combination and the volume of the
plant can increase without changes in the equipment combination.

By selecting equipment in this manner, processing costs are kept

to a minimum, flexibility is retained, and future expansion is
possible without prohibitive cost.

The selection of the Specific pieces of equipment used in the
combination is based upon the following factors:

1. Sanitation and quality requirements.

2. Operating efficiency.

_ 17 _

3. Space requirements.
4. Operating cost.

5. Initial cost.

6. Future expansion.

Sanitation and quality requirements were the first consider-
ation. All equipment specified is of stainless steel construction,
both on contact surfaces and exterior surfaces. Discussions with
representatives of sales outlets, manufacturers, and users,
indicate that there is no significant difference in quality and
acceptibility of high heat powder produced by different brands of
stainless steel equipment. All equipment combinations are capable
of producing extra-grade powder acceptable to the trade or
government. Under these conditions there seems to be no basis for
preferring one brand of equipment to another because of sanitation
or quality differences except the Operating efficiency differences
due to specific individual designs.

The different brands of dryers available, all have the same
basic thermodynamic principle underlying their operation. The
drying process is carried on in a turbulent mixture of heated air
and milk at a relatively high velocity. The efficiency of the
dryer and the hourly capacity is, however, affected by the design
of the component parts of the dryer. Counter—current dryers, in
vfliich the milk and air enter from opposite sides ot the dryer,

lueat the milk to a higher temperature and do not dry the particles

as :rapidly as in a parallel flow system. Many dryers on the market

-18...

at the present time use the parallel current system of drying.

The design of the powder—air separators also influences the
capacity and efficiency of the dryer. Dryers using single large
diameter separators cannot operate at as high a temperature and
velocity as dryers using a series of small diameter separators.
This occurs because as the diameter of the separator increases the
exhaust velocity increases, the smaller particles of powder are
then carried out the exhaust stack. In order to avoid excessive
powders losses, it is therefore necessary to install cloth powder
collectors in drying-systems using large diameter powder—air
separators. These cloth collectors sift out the entrained powder
in the exhaus air. If the size of the individual separator is
decreased, the exhaust velocity from each separator is decreased
and the velocity of the entering drying air may be increased
without loss of powder. This increase in velocity in the entering
air reduces the time the mi k particles remain in this drying
chamoer and because of this reduction in time in the chamber the
air heat may be increased without damaging the milk protein in the
powder. Also, drying systems using small diameter powder air
separators do not require cloth powder collectors to sift out the
entrained powder in the exhaust air.

These differences in dryer design result in differences in
space requirements for various brands of dryers. Dryers using a
:«ertical drying tube, large powder-air separators and cloth

CC>11ectors require from 12 to 20 feet more ceiling height than

horizontal tube dryers using multicone collectors. At present most
_dryer manufacturers use a horizontal drying tube and multiclone
powder—air separator coupled with increased air velocity. By this
means a reduction in initial cost and in operating cost have been
achieved because the equipment requires a small floor area and
attains a higher Operating efficiency.

Several types of evaporation equipment are available. The
common types of evaporation equipment in use in the dairy industry
at present are the single—, double-, and the triple-effect evapo-
rators. The principle involved in these evaporators is essentially
that of heating milk under vacuum, which reduces the boiling point,
and separates, condenses and withdraws vater vapor. In the single-
effect evaporator the steam is used once in the heating process.
In the double-effect evaporator the milk enters the first effect
and is heated to apyroximately 1600 F. It then enters the second
effect, where the vacuum iS~greater and the temperature lower and
there it is heated by the vapor from the first effect. The same
process is used in the triple—effect evaporator as in the double-
effect except that the temperature in the first effect is higher.

In-recent years a low temperature ammonia system of evapora—
tion and a recompression system have been introduced. The low
temperature system is used in the processing of concentrated fruit
juices where very low temperature is required to reduce the possi-
bility of heat damage. At present no performance data are available

on such equ'pment in use on wide scale in the milk industry. The

- go _

milk industry. The recompression system of evaporation compresses
the vapors used in evaporation. This raises the heat of the vapor,
and the vapor is then recirculated and used again for evaporating.
This system reduces the fuel and water requirements necessary for
evaporation. Relatively few of these recompression systems are in
use in the milk industry at present and no performance data are
available for comparison with systems in common use. Because of
these considerations the low temperature ammonia system and the
recompression system were not considered for this study, although
their installation and use affects the time standard in operation
and production of milk powder.

The selection of evaporation equipment was therefore reduced
to a selection of either a single—, double— or triple-effect
evaporator. The single-effect evaporator has the lowest initial
cost. Since the steam is only used once, however, the operating
cost is greater. The double-effect evaporator reduces the steam
and water requirements by about one—half, and the triple effect
reduces the fuel and water cost by about two-thirds. The possible
saving in fuel and water requirements would dictate that triple—
effect evaporators be installed in all sizes of plants for the
sake of economy. However, triple-effect evaporators necessitate
unduly high milk temperatures in the first effect and this greatly
increases the possibility of heat damage to the milk protein.
Double effect evaporators have been installed in most of the plants.

The operating cost of equipment is a function of all the

-21-

inputs which are necessary to operate efficiently. Labor is the

 

largest item of manufacturing expense in the manufacture of dry
milk, A careful study was made in 1953 by Linley E. Juers and

E. Fred Keller in 18 large specialized drying plants in Minnesota
in order to obtain the cost of drying milk in specialized drying
plants. For the 18 plants in the study, labor costs averaged

34 per cent of the total manufacturing cost. Labor costs for the
various plants ranged from 0.68 cent up to 2.03 cents for each
pound of dry milk produced. The largest number of plants showed
costs between 1.00 cents and 1.10 cents a pound.

Table 2 shows the average labor cost per pound of dry milk for the

18 plants grouped by annual output.

TABLE 2.- Relationship between annual dry milk output per
plant and labor cost for 18 Hinnesota milk .
drying plants, 1953.

 

 

Annual dry milk Humber of Average labor cost per
outfit per plant plants pound of dry milk
million pounds ' Cents

Under 2.5 1 2-03

2.5 to 4.9 3 1.21

500 to Fiat/1 7 1012

7.5 to 9.9 3 1.02

10 and over

1...:

on Is
[.4

o

|._:

0

Average all plants

The average labor cost per pound of dry milk for the 18 plants
in 1953 was 1.10 cents as compared with 1.16 cents in 1947. This
reduction in labor cost amounts to quite a substantial saving. On
the basis of 1953 production, it amounts to an average of over
4000 dollars per plant. With an estimated 38 per cent increase in
hourly wage rates between 1947 and 1953, this reduction in labor
cost reflects a very substantial improvement in labor efficiency.
Much of this increased labor efficiency is probably due to large
output in 1953 than in 1947 since the minimum amount of labour
becomes the fixed cost of operating. As output is increased this
fixed portion of labor cost is spread over more units of output
and the resulting average cost of labor per unit of output is less.

The relation between annual volume of production and the dry
milk output per hour of plant labor is shown in Figure 1. It is
alparent from this figure that, in general, the plants with larger
volume have a higher dry milk output per hour of labor than do
plants with low volume. But with most of the slants producing in
excess of 5 million pounds of dry milk in 1953, some of the
relatively smaller plants had achieved manufacturing cost just as
low as plants having twice the volume and at the same time there
were larg variations observed between plants of nearly the same
output. These plant to plant variations indicate that factors
.geverning the labor efficiency varied from one plant to the other
51nd that the labor cost was one of the larg st variants in deter-

mining a plant's costs.

OUTPUT OF DRY MILK PER HOUR OF LABOR (Pounds)

 

I50

I

I40

83
o
T

IZOt-

”0--

I00 I-

no
0
l

on
O
I

70-

 

GOI—

i l l J L l I J

O I 2 3 , 4 5 6 7
ANNUAL PRODUCTION
(Millions of Pounds)

FIG. I RELATIONSHIP BETWEEN ANNUAL VOLUME OF PRODUCTION
AND DRY MILK OUTPUT PER HOUR OF LABOR, l2 MINN-
FROTA DRYING PI ANTS- I953

 

 

 

 

- 24 _
PR 0C EDUILE

The milk drying operation falls into the non—repetitive class
Of industry. It is one Of the most difficult operations to which
to apply time and motion analysis. The ordinary time and motion
study is made on short cycle operations of a few elements or steps

repeated many times per day.

Broad steps in milk drying Operation.— The sg'm milk was preheated,
moisture evaporated by boiling under vacuum, condensed, spray
dried and packaged. The Operations were carried on mainly in three
sections: namely, pan section, dryer section and packaging section.
Steps in Operation of pgn.section:.
l. Sanitizing, testing and heating the line.
2. Preheating the milk in two stages: first in the tubular heater
and second in hot well (enclosed type) with direct injection
of stewn.
3. Preparing the pan for boiling the mi k under vacuum.
4. Boiling of milk at regulated rate to desired consistency.
5. Maintaining rate of boiling under Specified tempe~ature and at
-desired consistency with centrel ever steam, vacuum and other
mechanical Operations.

0. Supplying of condensed milk to storage tank for further drying.

Steps in Operation of dryer section:

II. Sanitizing and testing the condensed milk lines, pumps, and

_ 25 _

meters.

2. Heating the drying chamber of the dryer and fitting the spra'
nozzles with pipe pieces in working order.

3. Koving condensed milk after preheating.

4. Raising the temperature Of the drying chamber to working order

d spraying of condensed milk at desired pressure.

.1)
i:

5. Regulating the drying temperature in chamber and spraying rate
for desired moisture content.

6. Testing the moisture content Of the powder and making necessary
adjustment in Operation.

7. Checking of Operation.

Steps in Operation of the packaging section.
1. Packaging of powder (filling in bags).

2. Weighing.

3. Stitching the ag mouth.

4. Handling to the warehouse.

Three commercial plants were selected according to represent-
ative size of the milk drying unit. A brief sketch Of work place
layout, showing the floor plans Of these three plants, are placed
in Appendix A. All of them are multiple products type dairy plants.
Dairy 'A' has a drying plant capacity Of 400 pounds of powder per
hour. Dairy '8' has a drying plant capacity of 1000 pounds per
liour. Dairy '0' has two drying units having capacity Of 1200 pounds

Iper hour and 2200 pounds per hour.

m
0\
I

The three plants under study have different layouts Of
equipment and working conditions. Dairy 'A' plant is in an
institution and is used for the purpose of training and production.
It works casually as and when necessary according to demand. It is
a compact unit comparising of a single effect pan and horizontal
dryer with werking platform at a height of 12' from the ground
level. It has powder packaging unit at the basement floor. Dairy 'B'
is a very Old plant pan operation, drying Operation and packaging
each being done at different floors and separated from each other.
It has a double-effect pan and a horizontal dryer. Three Operators
are required, one at each section of Operation. The plant works
most of the time of the year. Dairy '0' has fairly large plant.
There is a new dryer Of 2200 pound per hour capacity. It works for
about nine months of the year. The dryer is used regularly and the
other serves as standby. Both of the dryers and the powder
packaging unit are installed on one floor and in one hall. The two
single—effect and one double-effect vacuum pans are installed at
the second floor away from the dryer house. All the three sections,
i.e. pan, dryer and packaging have one Operator working at each
section.

Considerable credit must be given to the management Of these
companies for granting permission to make such a study so unusual
to the dairy industry. The first thought Of a dairy worker on
having a stop watch check his work is that the manager is checking

on him and is dissatisfied with his production. It was necessany

- 27 _

to use a great amount Of diplomacy and sell the worker on the
purposes of the study. By proceeding on this basis, the entire
study was completed without incident and in a spirit of mutual
good vill. In the mass production industries, this problem would
not present itself as their workers are familiar with the use and
functions of time and motion study.

Motion study is commonly defined as the study Of the motions
used in the performance of an Operation for the purpose Of
eliminating all unnecessary motions and building up a sequence
of the most useful motions for maximum efficiency. When determining
the method of greatest economy for a specific job, consideration
must be given to all factors affecting the work and the Operator
such as materials, tools, equipment and the work place layout.

For developing a better method, the following four approaches are
generally used during the study of existing Operation:

(a) Eliminate all unnecessary work. (motions)

(b) Combine Operations or elements.

(c) Change the sequence of Operations.

(d) Simplify the necessary Operations.

In order tO make above approaches there are various tools
generally used such as process chart, flow diagram, activity chart,
man and machine chart, Operation chart, and sine chart. Of course,
not all Of these different methods would be used on any job. After
developing the improved method, the time standard is determined

foz'each element Of operation. The next step involves training

the Operators.

In the present study of motion and time, an attempt has been
made to determine accurately the standard number of minutes or
hours that a qualified worker should take to perform drying
Operation. The time is determined for working at a normal pace
with the present available tools and equipment under the normal
working conditions prevalent in milk drying plants in U.S.A. It
was not possible to train the workers nor was it desired as the
Object of the present study for rate setting or wage incentive
design.

According to the above described method the operations Of
three plants (A,B and C) were studied repeatedly and with the
help of process chart. An analyses of each step in the manufactur-
ing process was made for devising an improved method. Careful
study Of process charts shown in Appendix B will reveal that in
the graphic picture of steps in the old method certain unnecessary
Operations were eliminated, one Operation was combined with
another, a better route for the movement of Operator vas found,
delays between Operations eliminated and the sequence Of Operation
changed under the usual practice. The process chart usually should
be based on either the man, showing in sequence the activities of
Operator, or the product showing in sequence the steps that the
product goes through. The chart in this study is the man type

since efforts were made to indicate the standard man-hours required

f

_ 29 _

for cycle of operation with respect to variation in layout of the
equipment in different plants under study. From the summary of the
improved method process chart, as in Appendix B, it was found that
in dairy plant 'B' in milk drying Operation the number of Operations
were reduced from 23 to 18, number of movements reduced from 23 to
16, and the total movements decreased from 1009 ft to 821 ft. The
total observed time for the cycle of Operation was reduced from
38.69 minutes to 25.4 minutes for a saving of 34.3 Percent of the
time.

The next step was to make repeated observations of the process
with each equipment. Each operation was broken down into elements
or steps that were convenient to time. When it was reasonably,
certain that each step of a particular operation was followed by
the worker without change, a time study of the Operation was made.

The watch used was a decimal minute watch with one sweep of
the hand divided into one hundred parts of one hundredth of a
minute each. All time recorded was in minutes and hundredths Of
a minute.

The method of timing sod was the "snap back method". This
method is Open to some criticism in that some small amount of
time is lost in the snapping of the hand back to zero at the end
of each element, even though the watch automatically starts again.
Liost of the criticism of the system occurs when it is used for

I“ate setting. In this study, rate setting was not involved. Carroll

estates (1943) "While Observing a long series of very fast elements,

-C‘ 4-1....

layman to understand. In all industiral applications 01 tine study,
it is desired to find the time required for an average worker to

perform a given task. For this reason, the performance is rated

l1)
(’1

to the effort of the particular worker. Workers vary greatly in
their method and speed of performance, this range usually being from
one-third of normal performance to twice normal performance.
(Carroll, 1943).

In this study it was desirable to arrive at the time required
for the average worker to perform the task. All the operators were
rated on a basis of 100i to 120$ for an average operation. The

rating of the performance made it possible to arrive at normal
time for the elements and the cycle.

Allowances were then considered and applied to the normal
time for the cycle. The concept of allowances is one that may_come
as a surprise to some Of the plant managers. Many of the managers
like to believe that they receive clos to sixty minutes work per
hour from each plant worker, but such is far from actual case.
Allowances must be made for personal needs, fatigue and unavoidable
delays.

The value of these allowances depends very much on the type
of work involved. In some types of work such as blast furnace
work in steel mills, the allowance may run as high as 50 percent,

while in light work under good conditions it could be as low as

5

...J

aercen . Most shop operations fit in a class for which 20 percent

i,

's normal allowance. (Carroll, 1943).

_ 3o _

the continuous method is invaluable. For practically all other
studies, the snap-back method is much preferred. The snap—back
includes a small e*ror in each reading. This is inconsequential in
comparison with the probable errors in human judgment included
when -ating the performance".

The elements of such Operation was recorded on the regular
time study sheets used by the Industrial Engineering Section of the

mechanical Dng'neering Department at hichigan State University.

Five elemental time values were taken for each step. Recording
the tine for five complete cycles required considerable time be-
cause the occurrence is of the non-repetitive type and takes place
only once in tmenty four hours. The five elemental times were then
averaaed arithmetically and the actual time for each element
calculated.

Only for the powder packaging operation, which was of the
repetitive type and of short cycle, was the "continuous method"
of timing adopted. Elemental time values were recorded for ten
cycles. Also it could be possible to analyze this cycle according
to the laws of motion economy into necessary THERDLIG as developed
by Frank B. Gilbreth in his early work in motion study, as in
Appendix - C'.

The most important problem of the study was encountered in
determining how to rate the perforaance and the method of applying

allowances. This will be the most difficult part for the dairy

-32-

The total allowance generally used in dairy industry is
20 percent; 5 percent for personal needs, 10 percent for fatigue
allowances, and 5 percent for unavoidable delay allowance. (Hall,
1952). But in the present study since the operator has enough idle
time during the cycle of operation of the equipment for the day,
the writer is inclined to assess 10 percent of allowance for the
total; i.e. 3 percent for personal needs, 5 percent for fatigue,
and 2 percent for unavoidable delays. This seemed to be a reasonable
allowance for this type of work which is unlike manufacturing for
market milk. The packaging section of powder plant involves
repetitive type of work and consequently the allowance for the
operator should be 20 percent.

The system decided upon to calculate and illustrate the total

1

standard time was ey graphical representation. Included are the
standard time for the manual Operation and automatic time required
by machines. The chart illustrates the percentage utilization of
the time of operator and his idle time.

The most significant feature in the operation was the auto—
matic time required by machine at different stages entirely
dependant upon the design and recommended method. These were the
main determinant of the duration of the cycle of Operation. Efforts
were made to accommodate the maximum of manual Operations to their
best fit during the automatic time of the machine to reduce the

length of the cycle of Operation and at the same time the idleness

of the operator. In the graphic representation of cycle time the

manual Operations performed before and after the automatic time of
machines have been termed as “external time" and that performed
during and within the period of automatic time of the machina as
"internal time". In order to reduce the cycle of Operation and
idleness time of Operator, efforts were made to reduce the external
time, internalize the external time as well as reduce the automatic
time. This method of reduction in cycle time of Operation resulted
in minimum manhours required for production of a unit quantity of

powder in the plant.

_ 34 _

RESULTS

TABLE 3.- Elemental times for operation of vacuum pan.

 

PLAEET A
Elemental description Elemengal time,m1nutes Averare Ratine
3 4 p 5 Q U
l.Sanitize and preheat 3.1 3.5 3.0 3.1 3.3 3.20 120%
first stage
2.Preheat second stage .92 .91 .85 .95 .87 .90 "
in hot well
3.Prepare the pan for 3.6 3.1 3.0 3.8 4.0 3.5 "
boiling
4.8tart boiling and 2.0 1.80 1.70 1.90 1.85 1.85 "

adjustment of steam
and vacuum

5.3alance the normal .58 .60 .50 .52 .55 .55 n
rate of boiling
6.Check consistency of .82 .81 .78 .79 .80 .80 "

condensed milk and
pump to storage tank
for drying

13mm 33

1.Sanitize and preheat 3.8 3.1 3.0 3.7 3.9 3.5 "
first stage

2.Preheat second stage 1.15 1.16 1.0 1.06 1.13 1.10 "
in hot well

3.Prepare the pan for 5.4 5.0 5.1 4.8 4.7 5.0 "
boiling
4.Start boiling and 5.2 5.6 4,9 4,5 4,8 5.0 w

adjustment of steam
and vacuum
.Balance the normal .86 .87 .81 .OO .85 .85 "
rate of boiling
6.Check consistency of .94 .92 .98 .96 .95 .95 "
condensed milk and
pump to storage tank
for drying

TABLE 3 (Cont.)

L)
U1

 

PLAHT C
Elemental description Elemental time,minutes Averase Ratinr
l 2 3 4 5 L a

1.Sanitize and preheat 2.9 3.2 3.1 2.8 3.0 3.0 12Q£
first stage

2.Preheat second stage 1.1 1.18 .90 .92 1.0 1.0 "
in hot well

3.Prepare the pan for 5.9 6.2 6.6 6.7 6.6 6.4 "
boiling

4.8tart boiling and ‘ 5.6 5.9 5.0 6.0 5.5 5.6 "
adjustment of steam
and.vacuum

5.Ba1ance the normal 2.2 1.92 2.0 1.88 2.0 2.0 "
rate of boiling

6.Check consistency of 1.15 1.12 1.0 1.13 1.10 1.10 “

condensed milk and
ump to storage tank
for drying

TABLE 4.- Summary of pan operation

Elemental description

in plants A, B and C.

Average elemental time,minutes

 

Plant A. Plant 3. Plant C.

l.Sanitize and preheat first 3.20 3.5 3.0
stage

2.Preheat second stage in hot 0.90 1.10 1.0
well

3.?repare the pan for boiling 3.5 5.0 6.4

4.Start boiling and adjustment 1.85 5.0 5.6
Of steam and vacuum

5.Balance the normal rate of 0.55 0.85 2.0
boiling

6.Check consistency of con- 0.80 0.95 1.10

densed milk and pump to
storage tank for drying

TABLE 5.— Elemental times for operation of spray dryer.

PLAHT A

Elemental time,minutes

Elemental Description 1 2 3 4 5 Average Rating

 

l.Start heating the .88 .88 .80 .89 .85 .86 120%
drying chamber
2.8anitize, test, and .92 .95 1.10 .99 1.04 1.0 "

make the condensed
milk line ready for
drying

3.Preheat the condensed 1.4 1.1 1.0 1.4 1.1 1.2 "
milk and create press—
ure in the line

4.Fit the spray nozzles 1.9.r 2.1 2.0 1.98 1.98 2.0 "
with pipe pieces in
working order

5.Start pumping condens— 1.1 1.5 1.2 .98 1.2 1.20 "
ed milk, open Spray
partially, check spray
and open full

6.Adjust spray with temp— .42 .3 .28 .
erature

7. Start powder conveyor, 11.0 10.5 9.0 9.5 10.0 10.0 "

et powder sam_31e,

mak. nmus~ ure tes t

8.1ake final adjustment .48 .50 .49 54 .AO - .50 H
of high-pressure pump

PLmW‘B

l.Start he ati n3 the 2.1 2.2 2.20 2,12 2.13 2.16 n
d1yingc whexbe

2.8anitize, sent, and 1.3 1.6 1.4 1.5 1,7 1.5 u

make the condensed
milk line ready for
drying
3.Preheat the condensed, 1.6 1.9 2.0 2.4 1.6 1.9 "
milk and create press—
ure in the line
4.Fit the spray nozzles 3.2 3.1 2.90 2.8 3.0 3.0 N
nith pipe pieces in
norking order

PLANT B

Elemental Description

Lu
~J

TABLE 5 (Cont.)

Elemental time,minutes

1 2 3 4.

Average

‘J‘I

Rating

G

 

5.8tart pumping condens-
ed milk, Open spray
partially, check spray
and Open full

6.Adjust spray with
t mperature

7.Start powder conveyor,
get powder sample,
make moisture test

8.Hake final adjustment
of high-pressure pump

PLANT C

l.Start heating the
drying chamber

2.8anitize, test, and
make the condensed
milk line ready for
drying

3.Preheat the condensed
milk and create press-
ure in the line

4.Fit the spray nozzles
mith pipe pieces in
working order

5.3tart jumping
ed milk, open
and open full

6.Adjust spray with
temperature

7.Start powder conveyor,
get powder sample,
mak- moisture test

8.2ake final adjustment
of high-pressure pump

condens—

spray

2.1 2.1 1.90 2.2 1.80 2.0

.52 .48 '.50

14.0 13.3 12.0 13.2 13.0

.49 .51

13.1

1.1 1.3 1.0

O
n)
01
O
[\J
(n
O
)J
r)

o
(D
C)
0
CD
0
9
CD
[\7

1.1 1.15 .95
2.12 1.90 1.98

1.1 1.0 .97

.28 .2 .2 .23 .32 .25
)08 601 .3. PI 50 :5 600 6.0
028 031 .33 .28 .30 .30

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A L3 o.— Summary of

in plants A, 3 and

powder packaging; of 10L ‘ lo.

")(Z‘TCI' bf.”
. A v
C O

 

Elemental description Aver: 3e ele:.extal tine,minvtes
l-‘lent A. llant I}. I'luzt C.

i.hemove the be; from shifter 20 .2 .18
to weigh—bridge

2.Fit a fresh be" and start .48 .33 .35
the shifter

3.Wei«h the neg and preposition .70 .75 .50
the spout

.p.

.Close the mouth 01‘ liner,
tie it 1ith cor push
it below
5.Close ne_
(xvi set
mcchine
6.51idc the be;
goeiticn it

CL alfid

1er bag, stitch it
aride the stitching

on tray and

7.8teck the bag, “re house
end oeiticn fresh tray
Tet"l tine requirei
.0: or 3‘13; on including
t.re house is:

P111Zt
Plant
Pleat

1.0

1.80 .98

1.52 1.9 1.10
I: x ;.3.5

r.
’l
L.

Ki!
U}
o

0

3-5
(twelve bays)
Clanual) (-e elianieed)

(Ilaiuirl.)

for comnlete c
the steepiné o.

J.“- : o l

iiillU'tOS per or:
3- v.03 minutes )cr h;;
C— 4.75L’i11utc. per he“

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sections of the manufscturin; opera tion cycle in a slant, vary

\_1.

free one plant to the other then cenfarod y3th 053
this study. The variation is due mainly the difference in plant
layout, .ise of the :lant, and to the difference in des'gn of
equiyment. The manufacturing process is the same in all the three
plants. It w: v be seen that the pan, dryer and bagging section

e: eh loc cnf ed at different floor and at a d'stance in a plant
result in incree. so of manhours fer unit of production.

A study of the floor plan of the la3 1t in appendix 'A' (a),
(b), (c) of the three plants A, 3 and C under s tud; indicates the
follo;in3:

Plant A. Fan and dryer are housed in vnly one room with
operative platform at a height of 12 ft above ground level. The
tender paczaging section is located in the basement having a
circuitous working path to it from dryer house. Only one operator
attends the operation in all the three sections since the plant
is very small and 3a nab1n sec ion requires only a small amount
of handling at intervals. The location of working platform of pan
and dryer at different level and packaging section being located
at the basement and at a considerable diste.nce from dr3er result

in the increase of the Imovenent time of the operator.

The location of pan and dryer in a compact unit in this p ant
result in the standard time in minutes for manual operation of
both the units (i.e. 9.90 +15.63) in much less than the corresyond—
ing time of both the units combined in the other two plants 3 and
C where pan and dryer are located in different rooms some distance

apart.

Plant B. All the three sections of Operation are located
separately on different floors and operated independently by three
Operators, one at each section. In this plant the total standard
time for manual operation is the maximum although the plant size
and production volume are less than the plant C. The standard time
of each section is also the highest in this plant due to old design

of equipment and defective layout.

Plant C. In this plant the drying and packaging sections are
located together on one floor with the improved equipment and
layout. The pan section is located in a different hall at a con-
siderable distance with clumsy fittings of old type. The result is
that the drying and packaging sections either sep rately or combin-
ed together have lowest standard time. If the pan section with
modern design of equipment would have been located together as a
compact unit with dryer and packaging this plant would have been
more efficient. Three sections are involved with three Operators,

one at each section. The drying and packaging sections are together

at one floor and ordinarily one Operator should have been able to
handle the Operation of both the sections. However, due to higher
volume production requiring the full time attention Of an Operator,
due to a production higher than Optimum quantity which can be
handled by one operator, each of the stations require attention

of an operator. This occurs even though the Operator at the dryer
has ample idle time which could be utilized for attending the
evaporator if located at the same place.

The reduction Of standard time in manual Operations, as
Observed in the present study, is dependant on two factors. The
first is that the layout of the plant as a compact unit to minimise
the movement of Operator and avoidance of unnecessary mOtions.

The second is the use of improved type of equipment with automatic
control devices resulting in the saving Of manual Operation and

repeated inspection.

Laber reqpirements.- The standard time required for complete cycle

 

of Operation during the manufacture of milk powder is comprised
Of man and machine time. The standard labor time required for
manufacture of a unit quantity Of powder is comprised Of actual
working time of Operator while the machine is either working or

at rest and idle time of the Operator during automatic working
time Of the machine. The total time required for manufacture of
unit quantity of powder starting from milk to the finished product

in warehouse with certain rate of productivity Of the man and

machine depend On the length of cycle time of the complete Ope-
ration.

The graphic representation and measurement of the cycle of
Operation of a section, as well as combined together in a plant,"
indicate the total man-hours required for manufacture of unit
quantity of powder taking into consideration the standard time,
automatic time of machine and total time for complete cycle of
Operation in each plant. This graphic measurement of the work
indicates also the productivity Of each plant besides indicating
the percentage of useful utilization and idle time of Operators
in each plant under study.

The graphic representations enumerated in Figures 2 and 3
are based on sequence Of operation by man and machine according to
the process chart followed during normal working conditions as
Observed.

Definition Of the terms used in the graphic representation:

External time — Manual Operation time before or after the
automatic working Of the equipment employed
during Operation.

Internal time - Manual operation time performed during automatic
working time of the equipment.

Automatic time- Working time of machine or equipment with the
aid of steam, electricity, gas or any motive
power. Such time may be dependant upon the pro—

cess design for the product or design Of equip—

and
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_ 48 -

ment or both.
Cycle time Of Operation — External time and automatic time.
Total service time of Operation - External time and internal time.
Idle time of the Operator during cycle Of Operation - Automatic

time minus internal time.

Graphic representation of cycle of Operation.- External, internal,

 

elements as in time observation sheet and automatic times are va—
riables depending upon the process, equipment design and layout of
flmgflmm.

_In Figure 2 the Observations for pan section Operation are in:

 

Plant A. External time - Element no. 1 2 4
Time in min. 3.204-.90 + 1.85 = 5.95

Internal time — Element no. 3 5 6
Time in min. 3.5*- .55 t .80 = 4.85

Automatic time

5.04710.0 + 30.0 = 45.0 min.

Cycle time external+hautomatic 5.95't45.0

50.95 min.

Total labor devoted = 5.95+ 4.85 10.80 min.
Idle time of Operator during he cycle of manufacture =
4-500 "' 10.80 = 34-02 min.

Plant B. External time - El-ment no. 1

m
in

Time in min. 3.5~+ 1.10 +5.0 =

V)
o
O‘\
0

Internal time - Element no. 3 5 6

Time in min. 5.0 t .85 4-.95 = 6.80

Automatic time 5.0 'f 10.0 *'30.0 = 45.0 min.

Cycle time = external automatic 9,604.4 ,0: 54.60 min.

\Jl

Ianual labor 16.40 min

Idle time Of the Operator during the cycle of manufacture =

45.0 - 6.80 = 33.20 min.

Plant C. External time - Element no. 1 2 4
Time in min. 3.0 + 1.0 -* 5.6 = 9.6
Internal time - Element no. 3 5 6
Time in min. 6.4 + 2.0 + 1.10 = 9.50
Automatio tine - 5.0 + 10.0 +’30.0 = 45.0
Cycle time = 9.6 + 45 = 54.6 min.

manual labor = 9.6 + 9.50 = 19.10 min.
Idle time of the Operator during the cycle of manufacture =
4500 - 9050 3 35.50 min.

Similarly for the drying section. In Figure 3 the

 

followings are he observations:

Plant A. Ex ernal time Element no. 1 5 7 8

Time in min. .861'l.2-+10.04-5.0 = 12.56

Internal time - Element no. 2 3 4
Tilne in min.l.0 + 102 4' 2.0 = 4.2
Automatic time — 25.0 min.

2.561‘25.0 = 37.56 min.

Cycle time
manual labor = 12.564-4.2 = 16.76 min.

Idle time Of the Operator = 25.0 - 4.2 = 20.8 min.

P161111: Bo

Plant 6.

External time -

Internal time

Automatic time

Cycle time
Hanual labor =
Idle time of the

External time —

Internal time -

Automatic time

Cycle time

Manual labor

Idle time of the

Element no. 1 5 6 7 8
Time in min.2.16r2.0-+.5-*1.0+'l3.1= 18.76
Element no. 2 3 4
Time in min.l.5-+l.9 +3.0 = 6.4

28.0 min.

18.76~r28.0 = 46.76 min.
l8.76+-6.4 = 25.16 min.
Operator = 28.0 - 6.4 = 21.6 min.
Element no. 1 5 6 7 8
Time in min. .30+l.0 +.25+6.0-+3.0 = 7.85
Element no. 2 3 4

Time in min. .85+l.0-*2.0 = 3.85

20.0 min.

7.85-+20.0 = 27.85 min.

7.85 +3.85 = 11.70 min.
Operator = 20.0 - 3.85 = 16.15 min.

Since the work of the packaging section is of a repetitive

type, the cycle time per bag has been studied for each of the three

plants as indicated in the summary of the time sheet and total

time required. The man—hours required for handling the volume

production per working shift of 8 hours has been calculated and

shown in the following pages.

_ 51 _

Standard time for cycle of manual operation.—

 

Plant A.

PkmtB.

manual standard time in_pan operation in minutes.
Normal time for cycle of operation = 10.80 min.
Allowance 10 percent of the normal time for the
operator and considering observed performance rating

10.8

at 120 percent, the standard time 1—20= 9.0 min.

= 9-0'*0.9 (10 percent
allowance)
= 9.9 min.

Standard time in dryer operation.

Normal time = 17.06 min.

%légé = 14.21 min.

Allowance at 10 percent normal time = 14.21-+1.42 =

at 120 percent rating normal time

15.63 min.

Standard time in packaging operation.

Normal time = 6.1 min.

Performance rating at 120 percent

Allowance 20 percent of normal time

Standard time = %4%'= 5.08 + 1.01 = 6.09 min.

Standard time in pan section

 

Normal time = 16.40 min.

'Performance rating at 120 percent

Plant B.

Plant C.

- 52 _
(Continued)

Allowance at 10 percent

16. O

1.20 = 13.66 +1.36 = 15.02 min.

Standard time =

Standard time in dryer section.

 

Normal time = 25.16;
Performance rating at 120 percent
Allowance at 10 percent
Standard time = 2%f%é.= 20.96+-2.09 = 23.05 min.
Standard time in_packaging section.
Normal time = 8.08 min.
Performance rating at 120 percent
Allowance at 20 percent
we

Standard time = 1 2 — 6.73+'l.34 = 8.07 min.

Standard time in pan section.

 

Normal time = 19.10 min.

.Performance rating at 120 percent

Allowance at 10 percent normal time

Standard time = 1%519.= 15.91-?1.59 = 17.50 min.

Standard time in dryer section

 

Normal time = 11.70 min.
Performance rating at 120 percent

Allowance at 10 percent normal time

Pkth.

_ 53 _
(Continued)

Standard time = l%4%9'= 9.75 .97 = 10.72 min.

Standard time in packaging section.

 

Normal time = 4.7 min.
Performance rating at 120 percent

Allowance at 20 percent of normal time

Steellldal‘d time = 31-..3 = 3091 0782 = 4.692 mine

TABLE 9.- Summary Of standard times of manual Operation

thtA

PkmtB

Pkth

from starting to manufacturing, minutes.

Pan Section Drying Section Packaging Section

9.90 15.63 6.09
15.02 23.05 8.07
17.50 10.72 4.69

_ 54 _

Time for manual operation per shift+of 8 hours and man hours re-

quired for unit production of 1000 lbs. of powder.-

After completion of the cycle of operation in the processing
for converting milk into the powder stage, the Operator has to do
the packaging of powder as well as the routine inspection of the

processing at intervals.

In Plant A

First operation cycle = 36.11 min.

Inspection at 2.5 min. per hr. for remaining period of the

shift of about 6.5 hr. = 6.5 x 2.5 = 16.25 min.

Bagging at 6.1 min— per bag of 100 lb. each for four hundred
pounds per hour i.e. four bags per hour for 6.5 hr. = 6.5 x 4 x 6.1
= 158.6 min.

Therefore, total hours worked in the shift = 36.11 16.25
158.6 = 210.96 min. = 3.51 hr.

Taking performance rating at 120 percent and allowance at
10 percent a total standard time = 3.21 hr.

The production of 26000 lb. during 6.5 hr. requires 3.21

man—hour. Therefore, production of 1000 lb. powder requires -

3.21 x 1000

._ O
2600 ‘ 1'“3 hr’

Since only one operator attended all the three sections, the

man—hours per thousand pound production = 1.23 man—hour per 1000 lb.

In Plant B.

 

Operation cycle = 52.14 min.
Inspection at 2.5 min. per hour = 16.25 min.
Bagging at the rate of 8.08 min. per bag for production of

1000 lb. per hr; i.e. 10 bags per hour during 6.5 hours production

6.5 X 10 x 8.08 = 525.20 min.

Therefore, the total hours worked for the shift = 593.59 =

9.89 hr.
Taking observed performance rating, at 120 percent and allow—
ing 10 percent over all personal, fatigue, delays, allowances,
the total standard time per shift = 9.06 min. 1
Since three operators worked one in each section of the plant

as described earlier, the total man—hours required for the shift

9.06 x 3 = 27.18 man-hr.
For production of 1000 lb. ponder, the man—hours required is

27.18 x 1000
6500

I!

= 4.18 man-hr per 1000 lb.

In Plant C.

 

Operation cycle = 38.05 min.
Inspection at 2.5 min. per hr. = 16.25 min.

Bagging at 4.75 min. p,r bag for 2000 lb. per hr; i.e. 20 bags

<

per hour during production period of 6.5 hours, time = 4.75 x 20 n
x 6.5 = 617.5 min.

Total normal hours required for froductien of 13000 1b. powder

28005 +1‘l3025 +61705 :3 671.53 Illin. = 11.19 hr.

Performance rating at 120 percent a.1d IFD allowance at the
rate of 10 percent. Total standard time for manual opereWion in
the shift = 10.25 hr.

Since three ewerators awe iced 011e in each of the three units
for the complete Operation in one shift, the total men—hours =
= 10.25 x 3 = 30. 75 mm1—hours.

m1 refore, for production of 1000 lb. of powder man—heirs
required = 30°15 x 10C0 = 2.36 man-hr per 1000 lb.
* 130CO

The labor reouired for the drying Operation varies as equip-
ment size and volume vary. But this does not var;r proportionately
but increases in discrete steps as dryer capacity or volume passes
certain magnitudes.

In th's connection it is worthwhile to mention the results of

two studies dea ling with spray drying costs. (K0111er et al,1957)

(Juers and Keller, 1957).

Iowa I'em mlts (Kolmer,pet al,_19 57). - With any dryer, the OHJGI ting

labor ost per hundred-weight of non—fat drying milk declines as

0

volume increased until the volume becomes great enough to require
a.other labor shift. Only one man is needed to o;erate the dryer
and evaporator on dryers having capacity of less than 750 lb. per
hr. At this and larger volumes, it is necessary to adda help rer to
handle and store the non-fat dry milk. Because labor is hired in

units of 40 hr., the labor cost per unit of output increases sharply

I
01
-a

I

as new labor shifts are added with a particular dryer, or as a plant
changes from a smaller dryer to a dryer with a capacity of 750 lb.

per hour.

While enumerating the processing costs in three model plants

studied,_of different capacity, it was indicated that proc-sslng
costs per unit decreases within the volume range of each eguipment
combination as volume increases. Each equipment combination, when
operated at its optimum (lowest unit cost) volume, had a lower unit
cost than a smaller equipment combination-operated at its Optimum
volume. The rate Of cost decline, however, decreases as volume

q

increases. The processing costs decline from 5.28 per hundredweight
for a 500 pound dryer combination to 5.06 per hundredweight for
650 pound dryer combinatiOn to 4.99 per hundredueight for a 750
pound dryer combination.

This decline represents a 4 percent cost reductiOn between
the 500 and 650 pound dryer combinations and on 0.8 percent reduction
between the 650 and 750 pound dryer combinations. he volume increase
was 18 percent in both the instances. Figure 4 gives the cost of
spray drying skim milk with several equipment combinations at

various volumes.

Minnesota results (Juers and KellerJ 1956).- For 18 drying plants
the labor costs averaged 34 percent of the total manufacturing

cost. Labor cost for various plants ranged from 0.68 cent to 2.03

-58—

cent for each pound of dry milk produced. The largest number of
plants had a cost between 1.00 cent and 1.10 cents a pound. It
was found that labor was the largest item of expense in the

manufacture of dry milk.

TABLE 10.- Relationship between annual dry milk output per
plant and labor cost for 18 Minnesota milk
drying plants, (1953):

 

 

Annual dry milk Number of Average labor cost
output per plant. plants. _per_pound of dry milk.
Million pounds Cents
under 2.5 _1 2.03
2.5 to 4.9 3 1.21
5.0 to 7.4 7 1.12
7.5 to 9.9 3 1.02
10 and over 4 0.97
(1) average all plants '18 1:1;

The average labor cost per pound of dry milk for the 18 plants
in 1953 was 1.10 cents as compared with 1.16 cents in 1947. This
reduction in labor cost amounts to quite a substantial saving. 0n
the basis of 1953 production, the saving amounts to an average of
over 3 4,000 per plant. With an estimated 38 percent increase in
hourly wage rates between 1947 and 1953, this reduction in labor

cost reflects a very substantial improvement in labor efficiency.

(Dollars)
1‘:

COST PER HUNDREDWEIGHT

 

f

FIG. 4

\.71

500 POUND DRYER COMBINATION
——-- 650 POUND DRYER COMBINATION
......... 750 POUND DRYER COMBINATION

 

L l I L J
| 2 3 4

VOLUME (Million Pounds Produced Annuolly)

(1"

COST OF SPRAY DRYING SKIMMILK WITH SEV-
ERAL COMBINATIONS AT VARIOUS VOLUMES.

THE STUDY IS THE RESULT OF THREE MODEL
PLANTS, IOWA STATE COLLEGE, AMES

_ 60 _

The relationship between volume of dry milk produced and
average manufacturing cost per pound in 17 Minnesota sprav drying
plants, 1947 and 1953 may be observed in Figure 5. The greatest
reduction in manufacturing costs occurred in those plants which
increased output from about 3 million pounds to about 5 million
pounds during the interval from 1947 to 1953. These plants which
were in the 4 to 5 million pound output range in 1947 and increased
to around 6 million pounds in 1953 showed only slight reductions in
manufacturing costs.

The plants in the 5 to 6 million pound and 6 to 7 million
pound ranges showed increased manufacturing costs. This indicates
that, for this type and scale of plant, the greatest cost reduction
through increased volume occurs at volumes under 6 million pounds
per year. Beyond this output, cost reduction resulting from
Spreading fixed costs is slight and other methods of increasing
efficiency are needed to achieve further cost reductions.

The average cost of manufacturing dry milk in 18 Hinnesota
spray drying plants has decreased since 1947. Data from these 18
plants indicate a total manufacturing cost of 3.23 cents per pound
of non-fat dry milk solids produced in 1953, which is a reduction
of 0.32 cent from the 3.55 cents reported in 1947.

The two most important cost factors are labor and fuel, which
represent about 34 and 28 percent of the total manufacturing costs
respectively according to the Minnesota results. Even with sub-

stantial increases in wage rates, increases in labor efficiency

(CenlsI

COST PER POUND

 

6.5
6.0%-
I7 MINNESOTA SPRAY DRYING PLANTS

5.5-
5.0— \\

\

\
45*" \\

 

 

 

5 6 7 8 9 IO II I2 l3 I4 I5 I6

ANNUAL PRODUCTION
(Millions of Pounds)

FIG. 5 RELATIONSHIP BETWEEN VOLUME OF DRY MILK
PRODUCED AND AVERAGE COST PER POUND

-62...

were large enough to cause a reduction in the per unit labor cost.

The output of dried milk per hour of plant labor varies con-
siderably from plant to plant. In general larger plants are more
efficient in the utilization of labor although there are large
variations between plants of nearly the same output. These plant
to plant variations indicate that management as well as volume,
plays an important role in maintaining labor efficiency.

The fact that labor cost is one of the largest variants between
plants sugg s s that the quality of management is a major determining
factor in a plant's costs.

The bigger wages demanded by managers of exceptional ability
are often, in fact, very low when viewed on a per unit basis and
compared to the_cost reduction that can be achieved. Even in the
smaller plants, managerial wages account for only about 0.1 cent
per pound of dry milk produced while variations in labor cost due
to labor management may be twice this amount. Economising on
managerial costs by accepting less capable management is a false
economy.

Larger economies can also be achieved in many cases by the
adoption of new types of equipment or new techniques waich improve
labor or fuel efficiency. Advances in both processing and product
handling equipments have been quite rapid in recent years and plant
managers should stand ready to appraise and adopt any advance which

can improve their plant efficiency and reduce costs.

4.

CKEJK LIST FOR IKPRGTISC OPERATICH

Can the solid content of the skim milk be standardized uniformly
throughout the process cycle?

Can the uniformity of the rate of flow of milk be maintained
from reservoir tank to the process?

Can gravity feed eliminate the use of pump between reservoir
tank and the preheater?

. . ‘ . o .
Can the instant heating arrangement be made to attain 200 F in

few seconds without any damage to protein of the milk?

Can air operated values he used to Operate the flow of milk in
the process to avoid wa king and manual operation and thus

save labor?

Can milk be preheated before evaporation while flowing through
a jacketed pipe with steam under high pressure and temperature,
from storage tank to the evaporator in order to eliminate the
tubular heater and extra pump?

Can steam be injected directly in the above arrangement of milk
flow in order to aerate the milk and increase the temperature?
Can the hot well be eliminated by direct injection of steam

and hot air in the pipe in the above arrangement?

Can the inlet of milk into the evaporator be regulated according
to the rate of evaporation with the help of a regulating valve
acting according to the velocity of vapour flow from evaporator

to the condenser?

10.

ll.

l2.

l3.

14.

16.

17.

Can the above inlet milk regulating valve Operation be linked
to Operate directly the steam inlet valve into the evaporator
and the water inlet valve of the condenser for admitting the
proportionate flow of steam and cold water?

Can the above three valves for milk, steam, and water be
operated by an adjustable governor hydraulically or thermosta-
tically Operated for quantitative and qualitative control
during condensing milk into the evaporator?

Can the investment in installation of the above control
equipment be justified by the savings?

Can the evaporator be fitted with an indicator to show the
percent of solids of the condensed mi k or percent of the
moisture content of the condensed milk automatically with
recording devices?

Can the above recording pen be used or connected to give a
signal after crossing the limit of certain required consistency
of the milk either through an electric bell or glow of red
lamp?

Can an indicator of above type be fitted to give alarm signal
in the event of difficient supply of steam into the evaporator
or of its sudden failure?

Can the spray of milk into the dryer be regulated through the
opening and closing of delivery value of high pressure pump
governed by the fluctuation of temperature inside the dryer?

Can the spray of milk into the dryer be made to attain more

18.

19.

-65—

turbulent flow to perform drying under the principle of high
temperature short time taking care to prevent damage of protein
of the milk?

Can the spray of milk into the dryer in multidirection be
adjusted in a manner so as to attain maximum utilization of
heat under Optimum condition?

Can a saturation point be fixed for maximum utilization of heat
under dryer Operation with optimum output of powder and for
different products under different working conditions?

Can a characteristic curve be drawn on the fixation of above
saturation point and a direct relation of variation or percent—
age deviation of this curve in relation to the fluctuation of

exhaust temperature of the dryer be established, for recording

and expressing the dryer control?

2.

REC OI.L’.”""TDAT I CI?

The layout Of the equipment should be desirned for the most
compact unit in a milk powder plant to enable the Operator
work at maximum efficiency and at the least man-hours required
per unit of production of milk powder.

pAll the units under operation should be located on one floor
with least possible distance from one unit to the other with
control panel in the middle.

Reduce cycle of starting operation to gain longer production
hours by elimination of waste motions and rearranging the
sequence of operation.

Internalise external time; i.e. perform maximum amount of
manual vork during automatic operation of the equipments into
the process.

In the process of manufacturing milk powder, the condensing
Of milk by evaporator requires the longest time anong all the
elements of Operation. Efforts should be made to perform all
other elements in the startizg operation during the longest
element Of condensing Operation. When beginning the heating of
evaporator, the preheating of milk by instant heating process
for the fraction of a minute and heating of the dryer should
be completed before the condensed milk is ready for spray
drying. This arrangement will reduce the cycle of starting

Operation and result in more production hours with increased

43
0

plant

_ 57 _

efficiency.

Reduce labor by efiezting improvement in methods, employing

improved design of equipment and by employing automatic control

devices as far as practicable.

For smooth working of the operation and efficient maintenance,

the improvement in design of fittings is necessary to meet the

following defects normally eXperienced in a dryer.

(1)
(ii)

(iii)

(iV)

(V)

(vi)

Spray nozzle gasket gets amaged due to fitting defects.
Spray nozzles get choked due to burned or some foreign
particles in the milk although there is strainer over the
pressure pump. There should be a gage to indicate the
gradual choking of the nozzles. Every eight hours spray
nozzles have to be taken out one by one and cleaned of
deposited solid particles.

Gland leakage Of high pressure pump along circulating
water.

Gland packing for plunger made of compressed fibre lasts
about two weeks. It can be replaced by spring type metallic
packing.

When the electric motors driving the intake and exhaust
fans into the dryer fails, the high pressure pump floods
the dryer with milk. There should be device to stop the
high pressure pump when the fans fail.

Unless the pre—heater is full Of water or milk, the steam

inlet should not Open for preheating the liquid.

70

The following automation can be used fo

in cue lity and quantity althoug h not no

the production of milk powder at

. . t . o .
(a) Instant heating of milk at 30C F l
elim nation of tubular heater and h

Tse of t‘n crIO-compre .ien for attai

(‘0)
(c) Us< a

' I. o ‘ - o
Olf—(ll‘: Off-31 OI".

liquid controller between pre

valve at the

control the consistency

. . r n
V r .0 17.11.11 ( any-

1 r. ,
CQAQLGAHCC.

Of lechallis trap for pumping c

(f) Use

CN'f' 9.. _)0I mki

J- ‘51:,"

«4 ~* I'l‘ ~"v‘ '
pilint t veCLRflh. ..il

LOI' C."
”:ith the help Of
motive power for the

131131? 0

It has previously been reported that on

operate the evaporator and dryer having

hr. ity, but the

spas

in an ideal plant having capacity

one an cill be needed to operate

valve to ba
11.1130 tne 0 """

u'lw «an
J.tl. .- b-J—xc.

steam and vacuum and

present study enables the author to sa"

r attainin~

\J

improvement

cestt ily economy of

h'gher working efficiency:

n few seconds and

at well.
ning fuel economy.

.' r r‘ -' - r—~ :-
aeater and evapcratcr.

delivery of eveporcter ta

lance the “reportion of
rater to enszre

I

prevent i':e uent

-‘

:ndxx.:ea iHn; fzo l the

l operate automatically
will avcid the use
is needed to

ly one-1:8} .2:

dryer of 750 lb. per

up to 1000 lb. :er hr.

all the three units

from evep racer DC the powder paOLagizig.
Determination of standard time for each

element OfO Opel ait

~69-

for manufacture of skim milk powder is subject to further
modification based on more refined and accurate data.
Further tine study a;;ears necessary for determining the
monetary losses sustained per unit production of milk powder

in unbalanced and plants outmoded.

SULHARY AND COKCLUSICHS

To make the most profitable investment in a new set-up and
to make useful utilisation Of the investment already made for
manufacture of milk powder, dairy plant managers and directors
need reasonably accurate information on fundamentals Of management.

In the present study it was found that the standard time of
Operation and work required for production Of 1000 lb. Of powder
varied considerably from 1.23 man—hr. to 4.2 man-hr. The smaller
plant was more efficient in utilization Of labor than the larger
plant which had units on different floors with a separate Operator
for each unit.

The reason for the layout of such outmoded plants is that the
milk drying untis were acconnodated in multi-product plants as
subsidiary units in the available Space without the scientific
planning d sired.

In a nulti-product plant in which the receiving and separating
equipment for milk are required for other products, the drying
Operation is used as an outlet for the plant surplus (without
additional inputs) with a view to maximise the profit.

In butter plants, the max'mizetion Of the profit is attempted
by addition of a skim milk drying unit and the drying operation
becomes the major source Of revenue. The prime consideration in
these plants is to have available facilities which will add

flexibility to the overall plant Operations and also dispose of

- 71 _

surplus skim milk as economically as possible. But the rate of
utilisation of szim milk powder for human food has increased
tremendously making it a major item of dairy product in the whole
world and milk drying operation is a major source of revenue for
the plant. As such it deserves all the more economic consideration
now than ever before and the management needs more to look closely
at the work and workmen.

This comment along with the method of motion and time analysis
used in the data collection for this thesis will give an excellent
basis for work simplification, methods improvement, cost reduction,
invaluable information on a company's Operation and improved
engineering design Of equipment and plant layout. In a properly
designed plant one man can Operate spray drying equipment with
a capacity of 1000 lb. per hr.

The machine cycle time Of an Operator varied from 45 to 5,

minutes, of which the Operator was idle from 34 to 38 minutes.

Suggestions are presented for decreasing the idle time.

_ 72 _

APPENDIX A

Floor Plans Of Plants Studied

-73..

 

 

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—76—

APPENDIX '3'

Flow Process Chart

_ 77 -

KILK POWDER DRYING OPEIITICH

 

PLANT A
Step Old Method Dis— Time
tance in
in ft. fiin.
1 Open steam by pass valve to heat the coil .18
mO spray nOzzle Of the dryer 35
2 Open all the nozzles by pass valves .52
TO containing temp. recording chart 30
Open almira
3 Pick up recording chart and close almira .65
TO temperature recorder 40
4 Fix up chart On the recorder .25
To mechanical shaker 5
5 Start the shaker .10
TO condensed milk preheater circulating
pump starting switch 25
6 Start circulating pump with water for .58
circulation in milk line
To pressure pump 12
7 Start pressure pump .24
To spray nozzles 70
8 Open, wash and fix nozzles in pipe pieces 3.0
and close all nozzle valves
To circulating pump switch 70
9 Stop circulating pump .’4
To spray nozzles 60

_ 73 -

KILK POWDER DRYING OPERATION

 

(Cont.)

Step Old hethod Dis— Time
tance in
in ft. Min.

10 Fix up pipe Pieces with spray nozzles 3.0
in working Order
TO main steam valve for heating the coil 35

11 Open the steam vs vs fully .3
TO drying chamber exit air damper 20

12 Open the damper V .2
To blower fans starter 25

13 Start the inlet and outlet blower fans 1.5
and shut Off
To condensed milk storage tank 50

14 Open the outlet valve Of the storage tank .5
To starting switch for milk pump an 15
heater condensate pump

15 Start milk pump and condensate pump for 1.0
the preheater
To pressure pump 12

16 Start pressure pump and develop pressure 2.0
up to 1500 pounds and shutt Off the
pr ssure pump
To blower fans starter 50

17 Start the blower fans for raisins .5
temperature Of drying chamber— await for
the rise of temperature in drying chamber .16
To hi—pres ure pump starter (alternative 5
arrangement)

Step

I...)
\D

I.
r.»

IILK P WDER DRYIEG OPERATION

(Cont.)

Old Method

Restart hi—jressure nump

.‘I ,
Co spray n zzles

Owen nozzles partly, check the syrey and

open full

To powder conveyor switch

Strrt conveyor

GJt sample of powder from beg
To laboratory for moisture test

Testirr of moisture content in gender

‘N...)

5nd record it
To hi—precsure pump

Adjust hi—jressure pump to desired

To outlet sir dnmper

Adgust arm or to desired temperoture

_ 1.. ,__- . A .. ,w.
'er pccnaxlng room for gender saw,

Dis—
tance
in ft.

35

10

J)

.C.

1.10

h

\J‘I

Step

f“)

\_)'1

—~J

O)

_ 30 _

flILK OWDER DRIII.G O‘”YATI(-

PLAET A

1. . “.r ,4 .I '

0:01 rt .m v.1.Ve to he: t the cell

. ;‘ °—.-' ,-. u" rv 1. ‘. rx ‘ *- ‘ ‘L 4' ‘ H '~'\ 54

To ure ing engine: “11 outlet ee..1_ OJ.
.4 2,-,‘ ~ -4 w, - .-- .-

Cpen Lum;cl, stert1’31ma1:el, fii u}

vw-A -‘ \m‘ -V~-~ firm fl ‘- ~

emf. leecidinp cLeit out or a no:

,_ .1. '4.

L.tU8 (EC/‘1‘-N 'eCL to 1.0

To 1lover fans starter

Start blower fans for heating the drying
C11r11:1L‘ r311

To condensed milk “rehe: trr pumps starter

r v -n . 1" r1 * v' .
‘tart co;1«; eised mil“ greheeter OU~US Lith

'5". (1:4- U C r

To hi—pressure pump

tzlrt hi- >ressure pump With r.uter and
1

rculete it tnrou :h the no"zle by pan
0 and shut off the pump

F10 c)

ya

i:
{'1 Cd'~'."‘lr“‘7 ’ I" 1 -(“

10 s;- J no“; es

Fix u; spray nozzles with other pipe
pieces in merking order and open by
nan valves

To condensed milk storage tank

Open storage tark outlet valve

To-circulating punt for preheater

Start circulating Dump rith condone ed
mill: and also COI’ldGnLCSL‘O pump, simul—
tuneously

'30 ”mi—3ressui re :1t$3

_h

(J)
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70

CO

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in
1:21.11.

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1.0

(J)
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O

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\fl

LILK POWDER DR‘IKG OPERATICI

(Cont.)

 

Step Improved Method Dis- Time
tance in
in ft. Min.

9 Start hi—pressure pump, create pressure 1.0
in the line and expel water from the
line through nozzle by pan
To nozzles 60

10 top hi—pressure pump ,1

ll

12

13

15

}...|
C\

To hi-pressure pump

Close by pan valves and Open nozzles
partially

To spray nozzles

Start hi—pressure pump and develop pan
To temperature recorder

Check spray and open valves full

To powder conveyor switch

Observe variation of temperature after
Spray and adjust the damper

To powder pa kaging room
Start ponder conveyor

To laboratory

Get powder sample for moisture test

To hiwpressure pump

Test moisture content of the Wonder and
record the results

Adjust hi-presrure pump to required

pressure

60

30

1.0

1.5

»

.xr)
— \J‘L _.

’0')", '

..1 .* ‘r'r‘v‘ n -‘ \" r-J".A
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POWDER PACKAGIHG

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—84-

Plant C — Milk Powder Packaging Operation. (Cont.)

19.
20.
21.

22.

23.

27.
28.

29.
30.
31.

32.

33.
34.

35-

36.

Draw liner mouth to
goose neck.

Hold goose neck.
Hold goose neck.
Push liner below.

Grasp bag mouth's
other end.

Lift the bag a little
and release.

Fold bag mouth.
Hold the fold of bag.

Hold the fold of bag.

Hold the fold of bag.

Hold the fold of bag.

Hold the fold of bag.

Hold the fold of bag.
Hold the fold of bag.

Move aside the bag on
tray.

Release.

Reach to Sifter switch.
Push the switch to stop
Sifter.

Reach to bag.

TL

TE

TL

RL

TE

TL

RL

TE

TE

18.

19.
20.
21.

22.

23o

29;
30.
31.

32.

33.
34.

35.

36.

Draw liner mouth to
goose neck.

Grasp tag.
Tie liner mouth.
Grasp bag mouth's one end.

Grasp bag month's one end.

Lift the bag a little

and release.

Fold bag mouth.

Beach to stitching machine.

Grasp and move swinging
stitching machine to bag.

Stitch bag mouth.

Move stitching machine to
its position.

Release.
Reach to bag.
Grasp the bag tray.

Move aside the bag tray.

Release.

Reach to Sifter platform
vibrator switch.

PuSh the switch for
vibrating the bag.

Reach to bag.

_ 85 _

Plant c - Milk Powder Packaging Operation. (Cont.)

37.
38.

39.

40.

Grasp the bag.

Move the bag to weigh
scale platform.

Release the bag.

Move hand to empty bag.

TL

TE

TL

RL

TE

37.
38.

39-

40.

Grasp the bag.

Move the bag to weigh
scale platform.

Release the bag.

Move hand to empty bag.

l.

2.

3.

-86-

PLANT "C"

POWDER PACKAGING OPERATION

IN 50 POUND BAG WITH POLYETHYLENE LINER

DESCRIPTION OF ELELENT

When the bag.is full of.
powder close the sliding
door of the powder chute
under Sifter by a shutter,
switch off the sifter, un—
tighten the bag mouth from
the Sifter and remove the
bag to weighing scale plat—
form behind.

Pick up fresh bag from the
side and fit in the powder
chute of the sifter for fill-
ing; tighten the mouth, and
start the sifter again.

Turn towards weigh scale,
pick up spout and take out or
fill in powder in the bag for
correct measurement, read the
scale, keep away the spout

at pre-position.

Close the mouth of poly-
ethylene liner inside the
paper bag by making goose
neck and tie with cotton
thread knots.

. Straighten the bag, vibrate

it, fold the mouth edge of
paper bag for closing. Pull
the hanging stitching
machine and stitch the bag
mouth. Set aside the
stitching machine.

1.

2.

3.

CONDENSED DESCRIPTION AND
END POINT OF THE ELEEENT FOR
TIMING THE ELEHENT

Stop sifter and remove powder
bag from Sifter to weighing
scale platform. End point of
element - put the bag on
weigh scale platform.

Fit fresh bag in mouth of
Sifter chute for filling. End
point of the element -

Push the starting switch of
the Sifter.

to desired
of element -
spout in its

Weigh the bag
quantity. End
keep away the
position.

Close and tie the mouth of
polyethylene liner inside the
paper bag. End of element -
Push tied polyethylene liner
mouth below.

Close the mouth of paper bag
and stitch it. End of
element - set aside the
stitching machine..

PMth

7.

(Cont.)

Hold the bag from both 6.
hands and aside it over

the tray loaded on the

fork truck.

Drive away the fork truck 7.
after lifting the bag tray

to warehouse. Stack the bag
tray. Pick up another tray

and place it near the

weighing scale for bag

piling.

Remove the bag to tray for
further transporting it in
warehouse. End point of
element - release the bag on
tray.

Stack the powder bags in the
warehouse with the help of
fork lift truck. End of
element - position fresh day.

7.

CO

9.

10.

ll.

I
03
CD

I

Barnes, Ralph M. (1958) Motion & Time Study, Wiley, New York.

Carroll, Phil, Jr. (1943) Time Study for Cost Control, 2nd
edition. p.70, 82, 100, MoGraw—Hill Book Co. New York
and London.

'Dunlap, Harold G. (1949a) Work Simplification Pay off, Food

Industries 21:1356 59. October

Dunlap, Harold G. (1949b) How to make Work Simplification Work.
Food Industries 21:1548 49. hovemher

Emmons, James W. (1937) Janitors on Schedule.
Factory Hanagement 95:60. April

Engel, Robert C. (1940) Basic Plant Operations Improved.
Food Industries 12:32—33. Lovember

Farrell, A.W. (1952) Dairy Engineering, Wiley, New York.

Geiss, Albert E. (1954) Applying Time-Motion Studies to Dairy
Plant Cooperations, Proceedings of Second Hational
Dairy Engineering Conference, Michigan State University,
pp. 63-670

Gobb, A.F. (1937) Truckers and Sweepers on Bonus,
Factory Ianagement 95:47-48. March

Hall, Carl W. (1952) Operational Analysis of Dairy Plant
Operations, Thesis for Ph.D., Departnent of Agricultural

Engineer n3, Kichigan State University. (unpublished)

Hall, C.W. and William E. Shiffermiller (1954) Time Requirements
for the Cleaning Operations in a Dairy Plant. Hichigan
Agriculture Experimen Station Quarterly Bulletin
36(3):305—309. .

Hunzikor, Ctto F. (1949) Condensed Kilk and Kilk Powder, Otto
F. Hunziker, La Grange, Illinois.

Juers, E. 3nd E. Fred Keller (1955) Costs of Drying Hilk in
Specialized Drying Plants, Minnesota gr. EXperiment
Sta. B111. 435, {1.11119

14. Kolmer, Lee, Henry A. Hom1Le 31‘.d G.u. Ladd (195 7)S qwray Drv nr
Costs in Lou-'Jolume Milk Plants, Iowa Abricultural
Experiment Station. Special Report 19, September

15. Maynard, H.B. (1956) Industrial Engineering Handbook, MoGraw—
~Hill Book Company, N w fork.

16. Lerrow, Alexander (1947) Time Studies Store How to Reduce
Distribution Cost,Food Industries 19:794—95. June

17. Lundel, L.E. F rm Work olvglificot on, Mechani c: 1 Engineering

653565-660 £1115. ~46

18. Lundel, M.E. (1944) Work Simplification Applied to Peeling
Tomato , Factory management 102:89—91. May

19. Hadler, Gei cld (1950) Time and Lotion Study in C.nning Plants,
Food Industries 22:236-237. February

20. Felling, E.O. (1940) Changed Layout Saves,
Factory Kanageaent 98:64-65. February

21. Proctor, F. (1949) Labor Saving Methods in British Milk Bottling
Dairies. Proceedings XIIth International Dairy
Congress 3:145.

22. Rossmoore, H. and Aries, 11.8. (1947) Time and Motion Study.
Chemical and Enb ineering News. 117:1621. October 10

23. Sadoff, 3.1. (1944) Standard Times for Maintenance,
Factory Management 102:145-150. December

24. Stearns, R.A. (1945) Managerial Use of Time Study,
Iron Age 155:71. April 19

25. Teranes, 5.4. (1937) Less Flalkinr Here"flork n3,
Factory Hana ement 95:44-45. Larch

h)
(7“
0
*3
H.
r...
C)
" \
(.4
}_1
V.

r f . , "" . ' _ , -o A . l ..
L.D. (1)3o) T me & Lotion Stul for Jub Order S1‘.ops,
T ‘ ~ A ..
duooer Age 3 -

27. United States Department of Agriculture (1957) AgriCLfl t‘re
Statistics, WESTiIlJ’tOII, 13.0.

28. Ylisainger, A.V. (1911)La sier to Do Jobs Get Done Faster,

,1 l .. 1',.,..,.. ,4. r“. . ‘1'.»
chtiry managemeno p9:oo—ao. dune

29. fen Fechmann, (19i3) Operatin* Stand? 0rds in Cl‘_emicr 1 Industry,
Chemical H1110 ring Hens 117:1621. Octobe r10

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