.A STUDY or some PHYSICAL AND 911mm 1 . ‘ “

PROPERTIES OF ‘SEVEBAI. CDFMAMEBEIAL
DAIRY CLEANERS

THESIS FOR THE DEGREE OF M. S.
MICHIGAN STATE UNIVERSITY

HAROLD I. BARNUM
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A STUDY OF 501.33. PHYSICAL AND CIEZLICAL PROPERTIES OF SEVERE

COLZIEBCIAL DAIRY CLEANSERS.

A STUDY OF SOLE PHYSICAL AND CIIEIJICAL PELOPISRTIES OF SEW

COLCIERCIAL DAIRY CLAUSE? .

Thesis

Submitted to the Faculty of the Michigan State College in partial

fulfillment of the requirements for the degree of Master of Science.

by

Harold. J . Barnum

A

1929

THESIS

I fiYrV

PT "Tfi’i‘ ‘T_"’ 'mc
I‘LULucOu Manna“ ; I.)

The writer wishes to express his appreciation to Kr. E. L.
Anthony, Professor of Dairy Husbaniry, and :r. P. S. Lucas, Associate
Professor of Dairy Lanufactures, for their guidance, valuable sugges-
tions, and criticisms in carrying out this work, and in the preparation
of this thesis.

The author also wishes to express his ap.reciation to.mr. Bruce
Hartsuch, Associate Professor of Chemistry, for information, assistance,
and criticism on the analytical portion of the work, and to Hr. U. E.
Laycock, Associate Professor of Physics, for his assistance in carrying
out the photographic work.

Indebtedness is also acknowledged to the Creamery Package manu.
facturing Company, The Cherryafiurrell Corporation, and the Alleghezr
Steel Commany for their generous cooPeration in furnishing the metals

used in this experiment.

93866

TABLE OF COKTEfiTS.

INTRODUCTION
1. The Cleaning Process
II. Phases of Cleaning Peculiar to the Dairy Industry
III. Classification of Dairy Cleaners
REVIEW OF LITERAT‘RE
I. General
II. Germicidal Effect of flashing Powders
III. The Effect of lIetals on 1.2111:
IV. The Effect of milk on metals
V. The Effect oanlkalies on hetals
VI. Summary of Review of Literature
EXPEIILIEITPAL WORK
I. Object of the Experiment
II. Plan of Experimental York
A Chemical Analyses
1. Hedified Sodas
2. Soda Ash
3. Super Alkalies
4. Tri-Sodium Phosphate and Colloidal
5. Sodium Hypochlorite
6. Free Alkalinity
B Solubility Tests

C pH and Buffer Action under Dilution

Page

11

12
12
12
12
15
14
15
17
17
18

18

s7

D Relative Emulsifying Powers, Heasured by Drop
Number in Benzene and Butterfat

1. Apparatus

Relative Water Softening Powers

I?!

1. Preparation of Standard Hard Hater
Solution

2. Preparation of tandard Soap Solution

3. measuring Water Softening Powers of Cleaner
Solutions

F. Effect of Abrasives on.metals
G Effect of Each Cleaner on.metals
l. Petals
2. Solutions
3. Method of linking; the Tests
4. Photographic Jerk
RESULTS OF EXPERILEKTAL WORK AID DISCUSSION
I. Chemical Analyses
II. Total Solubility
III.pH and Buffer Action under Dilution
IV} Relative Emulsifying Powers
V. Relative Water Softening Powers
VI. Effect of Abrasives on.metals
VII.Effect of Cleaner Solutions on metals
A Loss in Weight
B Corroding Effect

C Tarnishing Effect

26

26

27

Page

D Fitting Effect 49

E Change in pH 49

F Change in Appearance of Solutions 50
CONCLUSIONS , 5G
BIBLIOGRAPHY 59
APPENDIX 62
Group Photographs 62

Individual Photographs 63 - 9O

INTRODUCTION

Seep has been used since ancient times. The prephets, Jeremiah
end Malachi (I) refer to its use during Biblical times. The potash
obtained from the burning of several plants growing in salt mrshes
see nixed with oil to form soap. Pliny (2), the Roman historian,
gives en eerly account of it as having been first made by the Gauls
(re. s cosiinstion of goat's east and the ashes of the beech tree.

W, e French chemist, early in the nineteenth century,
raised seep skim from empiricisn to a scientific basis. France for
my years wee the great soap market of the world, but during recent
years the mufscture of soap has spread to m countries. Through
resesrch end invention, a soap or cleaner for practically every type
of cleening has been developed.

an cleaning process is not thoroughly understood. The foremost
investigators have advanced several theories as to how and why soap
cleans. Recent investigations show that not one , but several factors
play s. definite role in the cleaning process. is s. result of his ex.-
perinnts, Hillyer (3) in 1903 was the first to advance s partial ex-
plmtion of the detergent or cleaning power of soap. His theory is
accepted today. He made use of the phenomena of interracial tension
between two liquids to explain his theory. According to this theory
the interracial tension will be greet between the two liquids when each

liquid has strong internal sttrective forces, or strong cohesion; and

it will be small when they have slight attraction for one another,
or slight adhesion. 3:311 interfacial tension will be caused by a
weak cohesion of at least one of the liquids and a strong adhesion
of the liquids to one another.

Billyer concluded from his experiments that, ”detergent action
was largely or entirely to be explained by the power of emulsifying
oily substances, or wetting and penetrating into oily textures, and
of lubricating texture and impurities so that they may be removed
easily”. He thought these effects were entirely explained by the low
cohesion of the soap solutions, together with their strong adhesion
to oily utter which results in low interfacial tension.

Later investigators have found other factors which are closely
related to those aiding emulsification, wetting power and lubrication.
mi (2) states that it is necessary to have the soap in solution. It
must be in true solution before it can become oriented and absorbed up-
on the surface of the dirt particle. numerous experiments with graphite
and lampblaok have shown that deflocculation or peptization of the dirt
particles is necessary. Chapin (4) found that deflocculation Occurs when
a certain minim concentration of absorbed oriented molecules of the de-
tergent upon the dirt particle surface has taken place.

housing is not necessary in the cleaning operation,'but according to
Jackson (6) is a useful preperty. Shorter (5) has pointed out that the
pressure on the convex side of a bubble is greater than on the concave
side. When the bubble rests on a surface it tends to become a plane and

will wet the surface more readily. Suds also seen to lift the dirt out

of the wash liquor, thereby preventing redeposition.

It say then be said that detergent or cleaning action is depend-
ent on the following factors: solution, emulsification, wetting, lubri-
cation, deflccculation, and foaming. In the ordinary cleaning process
these factors operating in conjunction with each other, cause the dirt
particle to be loosened from the dirt bearing substance, after which it

is carried away by floatation.
Phases of Cleaning Peculiar to the Dairy Industry.

In the cleaning of dairy utensils, the process differs from the
cleaning of other substances in a few particulars. In general there are
two incrtant considerations in the cleaning of dairy utensils: first,
cleaning the surfaces from adhering particles of the dairy product; and
second, sterilisation of the cleaned surface. The cleaning Operation
is not isportant, as no amount of sterilisation could produce the de-
sired result if the surface were not first cleaned. Some of the wash-
ing solutions themselves possess some germicidal effect.

Cleanliness is the most important factor connected with any food
supply. Milk is a universal food product. Therefore, in the handling
of milk and its products, cleanliness of utensils is a prime requisite.
Hill: in it's natural state possesses great adhesive preperties for sur-
faces with which it com" in contact. Its fat and solid particles make

excellent food and provide breeding grounds for micro-organisms. At

rocn or higher temperatures, bacteria multiply very rapidly in dirty

utensils. If the dirt particles are not thoroughly removed and the
surface sterilised, these bacteria readily find their way into the
eilk or milk product.

Kilt is a highly satisfactory media for bacterial growth. If
the bacteria are injected into the milk from the surface of dirty
utensils, reproduction begins immediately which results in lowered
quality of product, waste, and serious losses in many cases. The
health of the consumer is endangered if there should happen to be
disease organisms present.

When milk is altered by some intrinsic agent such as souring or
drying, or by some outside agencies, such as heating, the original
emulsions and colloids are changed or denatured and the solid and
liquid particles which are thrown out, adhere even are tenaciously
than the original milk to the surfaces of utensils. The cleaning
process then becomes very difficult. Because of the complex nature
of dairy products it is highly essential that all dairy utensils
should receive a thorough cleaning after each use. On many milk
pasteurisers a substance popularly referred to as “milk stone", is
found. This contains marly all of the original constituents of milk
in a denatured form. his milk stone isvery difficult to remve and
the -Jority of dairy cleamrs on the market will not remove it at all.

1 factor of considerable importance in the selection and use of
cleaning compounds for dairy equipmnt, is the effect of the cleaner
on the metal. Some metals used in dairy equipment corrode, pit, and

dissolve quite readily when they com in contact with albalies or acids.

According to Hausiker (6), "injury to the flavor and keeping quality
of the dairy product my be caused by the presence, even in very mi~
nuts amounts, of the metallic salts themselves which have a metallic,
bitter, puckery flavor; or by bacteria-selective influence of certain
-tallic salts. Furthermore, it was shown that the salts and oxides
of certain netals have distinct toxic preperties rendering the product
unsafe for consumption”. Thus it any readily be seen that a cleaner
which will dissolve the metal or the metal surface is very objection-
able, as some of the metallic salts will find their way into the milk
product. a pitted or corroded surface will be left which will more
readily facilitate the solution of the metal by the milk. Some of the
dissolved (8) natal or pieces of the broken metal will lodge in the
pitted or corroded surface in the washing process and will not be en-
tirely removed by rinsing. When the milk comes in contact with the
surface of the centainer the dissolved metal will be taken up by the
milk with consequent lowering of quality. The pitted surface affords
ideal lodging places for bacteria and dirt. From an economical stand-
point, the factory manager is interested in preserving the life of his
equipment as long as possible. Cleaners which wear away the surface of
the equipmnt rapidly are not desirable. The use of such cleaners makes
it necessary for the owner to repair and replace equipment frequently.
This is very expensive.

In the cleaning of dairy equipment, a satisfactory cleaner mist be
active enough to remove all adhering dirt particles, and must not be

detrimental to the equipment or severe on the hands of the user.

Classification of Dairy Cleaners.

 

Runsiker (7) gives the following classification for washing

powders available for cleaning creanery equipment.

1. Soap powders .

Haw cleaners on the market contain varying quantities of soap
powder. These soap powders are not desirable cleaners for dairy
equipunt as they leave a film on the cleaned surface which is diffi-

cult to rinse off and serves as a good medium for bacterial growth.
2. Neutral or Dairy Sodas.

This groin: consists of cleaners containing varying mixtures of
soda ash and bicarbonate of soda. They usually contain from 45 per
cent to 60 per cent of soda ash and from 25 per cent to 35 per cent
of baking soda.

3. Soda Ash Cleaners.
These washing powders consist of straight soda ash.
d. Omticised Ash or Special Alkalies.

This type of cleaners are very powerful cleaning agents. They
contain from 30 per cent to 60 per cent of caustic soda (neon), and
the remainder soda ash.

5. Trisodium Phosphate.

The basic ingredient of this type of cleaner is tri sodium phos-
phate. Some of them contain in addition to the tri sodium phosphate,
soda ash, sodium bicarbonate, borax, or sodium silicate.

6. Cleaners Containing Disinfectants.

These washing powders contain in addition to the cleaning ele-

nsnt some disinfectant such as hypochlorite or chloramine-T.
7. Colloidal.

Recently a new type of cleaner has appeared on the market which
is in colloidal form. They contain a colloidal base such as potatoe
starch together with soda ash, tri sodium phosphate, or sodium bicar-

bonate.
8. Detergents or Scouring Powders.

To this class belong a type of cleaners which depend for part
of their cleansirg effect on scouring by mechanical friction. Vol-
canic ash or pumice stone make up about 60 per cent to 70 per cent
of the cleanser which gives it its abrasive property. The reminder

is largely soda ash and sodium bicarbonate with a little soap.

Washing powders sold for dairy use vary widely in their ability
to clean satisfactorily and economically. There is need for more in-
formation in regard to types of cleaners met desirable for various

kinds of cleaning and equipment. It was for the purpose of shedding

cl

are light on the relative merits and faults of the different types

of cleaners that this work was undertaken.

REVIEJ OF LITERATURE AND DISCUSSION

Phillips, neck and Frandsen (8) at the Massachusetts Station
made a number of practical tests with each of thirty-six different
commercial dairy cleaners. The cleaners were classified into four
groups on the basis of their chief constituent. The classes were
sodium.carbonate, tri-sodium.phoSphate, free caustic, and soap. All
tests were made at 0.6 per cent concentration of the washing powder.
The washing powers were tested on milk bottles containing a film of
dried milk and the water softening powers determined by the amount of
cleaning solution necessary to soften standard hard water sufficiently
to make permanent bubbles by a soap solution. The emulsifying power
[as tested by shaking some of the solution with pure butterfat and the
free rinsing preperties tested on the finger. They summarized their
results by placing the classes in the order of their effectiveness as
follows; Water Softening'Powers: Sodium Carbonate, Phosphate, Soap,
Hydroxide. Washing'Powers: Sodium Carbonate, Hydroxide, Soap, Phosphate.
Emulsifying Powers: Soap, PhOSphate, Sodium.Carbonate, Hydroxide. Ease
of Rinsing: Sodium Carbonate, Phosphate, Soap, Hydroxide. Soap was not
recommended for dairy cleaning because of the suds and scum.it leaves on
the surface of metal, and the expense as compared with other equally as
efficient cleaners. They maintain that free alkali is too caustic for
hand washing, but can be used advantageously in power machines. They

believe that neither sodium carbonate nor tri-sodium.phosphate contain

 

 

m v r-v.
a

-4.

 

 

 

all of the good properties of'a cleaner and best results may be se-
cured by a mixture of the two. The following approximate analysis is

recommended by these investigators for the ideal washing powder.

Sodium Carbonate (anhydrous) 60%
Tri-Sodium Phosphate ‘(12H20) 40;";
Total Alkali as No.0}! 5875

Germicidal Effect .9}; Washing Powders

 

The alkalinity in commercial washing powders is of two different
types. The first is known as total alkalinity and is found by titration
with an acid. The second type is the free or effective alkalinity, which
the chemist calls the hydroxyl ion concentration. It has been found that
in working with various commercial powders the total alkalinity does not
correspond to the free alkalinity. Taylor (9) gives the following ex-
planation of the phenomena of the difference between free alkalinity
and total alkalinity. "When acids and alloalies are dissolved in water,
they ionize or break up to give positively charged H ions and negatively
charged OH ions respectively. The intensity of acidity or alkalinity is
due to the number of H and OH ions reSpectively in a given solution.
Hydrochloric and sulfuric acids are strong acids, because in solution
they give a large number of H ions. Acetic and boric acids are weak
acids because they give comparatively few H ions in solution. In a
similar manner sodium bicarbonate is a relatively weak alkali because
it gives relatively few on ions in solution. Sodium carbonate, tri-

sodium phosphate and sodium hydroxide, on the other hand, are strong

alkalies because they give a large number of OH ions in solution".

In the cleaning process with alkaline powders, sterilization is
accomplished to a certain degree. According to Sherman (10) and Taylor
(9) the germicidal actionof washing powders is in a large measure due
to the true or free alkalinity. Sherman showed that an alkalinity of
pH 12 will kill Bacillus typhosus in the cold with five minutes exposure.
The same results were obtained with a solution having a pH of ll at
113° F. He was successful in killirg spore forming organisms at low
temperatures in very strongly alkaline solutions. Spores which with-
stood the temperature of boiling water for two hours, were destroyed
at 176° F. in washing powder at a pH of 12. Phillips, Mack and Frandsen
(8) say that all powders used in their determinations at a strength of
0.6 per cent acted as disinfectants to such a degree as to make the
washing solution sterile.

Madge and Iawler (ll) studied the effect of alkali solutions on
bacteria found in unwashed milk bottles. They give the following re-
sults for the number of bacteria surviving the action of sodium Irv-
drcxide solutions of different concentrations for various periods of
holding at 120° 1?. Eight million bacteria were used in each original

Concentration of Alkali

 

Em Uslflor 0.3707 U. I: 0.7;; TOG/(5

 

 

 

"ifiimmea P . ,pH 12;§’ _pH 15.0 ,pH 13.2 ,pH 15.4
1 10,000 5,000 200 100 0
2 5,000 1,000 150 50 o
3 2,500 500 100 so 0
4 1,500 150 50 o 0
5 1,000 50 20 0 0

 

A study of the above table readily reveals that there is a cor-
relation between time of exposure and concentration of alkali. The
l.0 per cent solution was very effective in germicidal action.

At the same time these investigators studied the effect on bac-
teria in dirty milk bottles of a popular dairy cleaner containing
mixtures of sodium hydroxide and sodium carbonate. Stronger concen-
trations of alkali were used. Four million bacteria were present in

each original sample.

Concentration of Alkali

 

 

 

 

 

 

"m m 62?}; 1.0% 7733‘
was pH 10.8 pH 11.0 pH 11.2 _pH 11.6
1 50,000 20,000 500 200
2 25,000 10,000 400 so
3 15,000 5,000 250 o
4 10,000 3,000 150 o
5 5,000 2,000 50 o

 

l‘

The results of this test indicate that a higher percentage of
sodium hydroxide and sodium carbonate was required in the commercial
command. than in the straight sodium hydroxide to give the same germi-
cidal efficiency. The authors conclude that the concentration of hy-
droxyl ions appears to be an important factor in bacterial destruction.

Lavina, Peterson and Buchanan (12) made investigations into the
germicidal efficiency of sodium hydroxide, and of sodium hydroxide-
oarbonate mixtures. A papular commercial washing powder containing
2 per cent NaOH and 2.66 per cent M2003 by weight was used in compari-
son. The concentration of the connnercial compound and the mixture of
men ea H.200, was equivalent to a normal alkali and gave a pH of
13.18. The straight NaOH had a normality of 0.5 and a pH of 13.20.

A table was published showing the relation of the composition of

the alkalies at the same pH to killing times at 50° 0.

 

 

Alkalinity
by T itrat ion Concentrat ion Killing Time
‘Sample E. 11803 Nazcos Minutes
% %
HaOH 0.5 2.00 0 .00 40.8
mos-m2003 mature 1.0 1.30 3 .50 45 .7
Commercial Washing 1 .0 2.00 2.66 34.0

Powder

 

A study of the table reveals the fact that it required 6.8 min-
utes more for the straight NaOH solution to kill 99.9 per cent of the

bacteria than for the commercial powder at 120°F. At 141°F. the kill-

ing times were 8.5 and 11.75 minutes reapectively. The results indi-
cate that the presence of the carbonate in the commercial product
served to increase the germicidal effect of the sodium hydroxide pres-
ent at the same pH. The authors maintain that the disinfecting action
of naacos at 120°F. is nil. They believe the presence of the carbonate
enhanced the germicidal efficiency of the hydroxide. It would seem as
a result of this experiment that neither the total alkalinity nor the
Haion concentration alone is a direct measure of the germicidal powers
of these alkalies. These investigators conclude "It is conceivable
that the undissociated neon rather than the OH ion, penetrates the bac-
terial cell. In this case the concentration of the undissociated neon
becomes the determining factor in the germicidal efficiency of the alka-
lies. The addition of Nazco3 to the hydroxide would result in an inn
crease in.the concentration of undissociated neon and a corresponding
increase in the germicidal action".

This phase of the cleaning Operation.is of interest to the Operator
insofar as bottle and can.washing is concerned. Meet cleaners which are
high in alkalinity are severe on the hands as well as detrimental to
equipment and cannot be used in other types of work. It is very desira-
ble to sterilize bottles and cans thoroughly. For this purpose a washp
ing powder should be used which will remove dirt quickly, has high dis-
infecting’prOperties, and will not severely attach glass or metals used

in'bottle and can construction.

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Recently a few investigators have made extended studies regard-
ing the effect of metals on milk and its products to determine the
cause of mny "off" flavors and poor keeping qualities. Hunziker (6)
states that, "In order for any metal to suffer corrosion, or to affect
the dairy product, it must be capable of entering into solution. Solu-
tion my be caused by the attack of acids, mineral salts, and other

constituents of milk, washing powders, chemical sterilizers, or brine".

Toxicity Hunziker (13) believes that with the scarcity of avail-
able data on the subject of toxicity of metals in milk that no standard
of toxicity can be established. Numerous examples may be cited, however,
that the salts of such metals as chromium, copper, zinc, and tin are
highly poisonous. Since these metals are more or less soluble in milk
it is quite important that they be not subjected to Operations which will
cause them to be more readily soluble if they are to be used extensively
in the dairy plant. Seligman (14) suggests that the following metals
have certain toxic effects on milk. He arranged them in the order of
their toxic effect. 1. Chromium, 2. Copper, 5. Zinc, 4. Lead, 5. Tin,

5. Nickel, 7. Aluminum. ‘

Keepig Quality and Flavor Hunziker (15) found that cepper lac-
tatos impart an intensely metallic taste to milk and milk products even
if present in minute quantities. The action of capper was found to be

mre intense in this respect than that of iron and iron salts. In cases

where poorly tinned equipment is used or the tin has been dissolved or
worn off by improPer cleaning methods leaving large surfaces of cOpper
exposed, the dairy product is not protected against the detrimental
action of the capper. After a series of tests in regard to the effect
of the various metals on milk, Hunziker (6) concluded that those metals
which showed definite corrosion in milk and acid solutions also had the
most damaging effect on the flavor of the milk product. In his work
nineteen metals were used. He found that iron, galvanized iron and
capper produced a marked metallic flavor in all products and.that zinc,
tinned iron and nickel silver caused the metallic flavor in the majority
of cases. Allegheny metal, tin and heavily tinned cOpper had no effect
on flavor and showed maximum resistance to corrosion and tarnishing.
The work of Hunziker has been substantiated by Guthrie and Roadhouse
(16) in regard to capper, poorly tinned copper and nickel silver.
Seligman (l4) agrees with Hunziker as to the effect of capper and zinc
on milk products. All three investigators believe that pure nickel is

not entirely negative as to its effect on the flavor of milk.

Effect 931.3153 Metals Hunziker (6) made an extensive study of
the loss in weight and corrosion of metal strips in sweet and sour milks
and cream, and in acid solutions. He used aluminum and aluminum alloys,
capper and capper alloys, nickel, sinc, iron and galvanized iron, tin
and tinned cepper, tinned iron, two ordinary chromium.steels and one
chromiumpnickel steel. The corrosive effect on the metal was greater

in the acid solutions than in milk products at the same acidity for

both. He suggests that acidity is the chief factor in metallic cor-

rosion and that some of the non-acid milk constituents exert a cor-
rosive protective influence. In general the corrosion was more in-
tense in the high-acid than in the low-acid products, and at higher
than room temperatures. He found that zinc, iron, aluminum, galva-
nized and tinned iron lost considerable weight in acid solution and
corroded quite severely. In milk and cream, c0pper, iron, nickel,
tin, sine, galvanized and tinned iron, monel metal, and nickel silver
exhibited the greatest loss in weight. Zinc, iron, capper and galva-
nised iron suffered the most corrosion. Allegheny metal, tin, and
heavily tinned cOpper showed maximum resistance to corrosion and loss
of weight in all the tests. Guthrie and Roadhouse (16) carried on a
similar experiment with metals immersed in cream. They found that
pure nickel lost heavily in weight in raw cream and that monel metal

and pure nickel lost considerable weight in pasteurized cream.

Effect of Alkalies on Metals

Very little literature is available on the effect of alkalies
on metals for dairy equipment. Phillips, Mack and Frandsen (8) im-
mrsed strips of aluminum, capper, nickel, tin and zinc in solutions
of washing powders having a strength of 0.6 per cent by weight. They
found that cleaners containing hydroxide attacked aluminum, capper,
and tin severely. Sodium carbonate cleaners also attacked aluminum,
capper, and tin, but less severely. They state that tri-sodium phos-
phate attacks aluminum and has very little effect on the other metals.

Runziker, Cordes and Nissen (17), in a recent investigation,

studied the effect of washing powder solutions on nineteen different

vi

r.

10

”tale. They used 0.5 per cent solutions of sodium hydroxide, special
slhli, modified soda, sodium carbonate, tin cleaner (containing HazPO4
and mam-04), tri-sodium phosphate, and a 0.16 per cent solution of tri-
eediun phosphate. The corrosion and weight losses totaled greatest in
sodium hydroxide and special alkali solutions. The next greatest total
losses occurred in the case of 0.5 per cent solutions of tri-sodium phos-
phate and sodium carbonate in the order named. The action of the modi-
fied soda was next in order. The 0.16 per cent solution of tri-sodium
phosphate and the 0.5 per cent solution of trisodium phosphate treated
with sodium chromate gave the smallest loss in weight.

The aluminum products used in these tests suffered by far the most
intense corrosion and loss of weight in all the washing solutions used.
The tinned capper and tinned iron products ranked next in loss of weight,
although the tinned equipment was much more resistant. Nickel silver
tarnished considerably in tri-sodium phosphate and tin cleaner. Capper,
iron, galvanized iron, and zinc exhibited more severe corrosion than the
tin-plated products. Nickel and monel metal showed only negligible weight
losses. The alloys: Allegheny metal, iscoloy, and Enduro, were most re-
sistant and practically iunmme to the action of all the alkalies.

The presence of a very shall amount of silicate of soda in the so-
dium carbonate prevented corrosion on the aluminum products. Corrosion
in the case of tin-plated capper and tin-plated iron was prevented by
edding a small amount of chromate of soda to the tri-sodium phosphate

rushing solution.

11

Dr. Prucha (18) of the Illinois Station studied the effect of
chlorine sterilizing solutions and washing powders on milk apparatus.
His results show that polished Allegheny metal was completely resist-
ant to the various sterilizing solutions, as well as to caustic, tri-

sodium phosphate, and sodium carbonate.

Summary _o_£ Review 33 Literature

 

Washing powders for dairy use may be divided into groups based
upon their composition. A few investigators are of the Opinion that
a mixture of two or more of these compounds is more desirable than
those containing just one compound.

Washing powders contain two kinds of alkalinity, free and com-
bined.

Investigators are not agreed as to the cause of bacterial des-
truction by alkalies. Some suggest that it is due entirely to the
on ion concentration and others believe it may be due to the OH ion
concentration and the undissociated NaOH together.

Metallic salts are without doubt the cause of many off flavors
and poor keeping quality in milk and milk products.

The metals used in the handling of milk and milk products differ
considerably in their ability to resist solution and corrosion by milk,
acids, and alkalies.

The chromium alloys appear to be the most resistant to the action

of alkalies.

12

OBJECT 0 THE EXPERILEHT

The primary objects of this experiment were to determine:

1. By chemical analysis the composition of each cleaner studied.

2. The relative solubility of the cleaners in water.

3. The pH and buffer action under dilution.

4. The relative emulsifying powers as measured by the dr0p nump
her in benzene and butterfat.

5. The relative water softening powers.

6. The effect of cleaner abrasives on metals.

7. The effect of each cleaner solution on metals.
PLAN OF EXPERIHENTAL WORK
Chemical Analyses

Samples of each cleaner were taken at random from barrels and con-
tainers as they are sold on the market. The cleaners were analyzed for
the fellowing compounds: total alkali as mega, sodiunicarbonate, sodium
bicarbonate, sodium.hydroxide, tri-sodiunxphosPhate, sodium hypochlorite,

and free alkalinity. All tests were run.in.duplicate.
Neutral or medified Sodas

Total Alkali (Ha20) (19) Feur grams of the cleaner was dissolved
in 500 c.c. of freshly distilled water. .A 25 c.c. aliquot containing

.2 grammar cleaner was pipetted off and titrated with .1 N301, using

methyl orange as an indicator. The per cent of Hugo was calculated

from the formula:

0.0. 01 I; HO]. X .3].

 

.2

Sodium Bicarbonate (nanco3) (19) Eight and four tenths grams
of the sample was dissolved in 50 c.c. of distilled water. This was
titrated with N neon until a drop of the solution added to a drop of
freshly prepared silver nitrate indicator on a spot plate gave instant-
ly a dark color. The per cent of hencoa was calculated from the formu-
1a:

0.0. N HaOH x 8.4

Le 1511?. Of sample

Sodium Carbonate (Kazcos) (19) The per cent of Nazco3 was cal-

culated from.the formula:

(gringo - (jélIaHCO x .3690) x 1.7097)

3

SOda A8110

Total Alkali EXpressed as Sodium Carbonate (19) Five and three

 

tenths grams of the sample were dissolved in 100 c.c. of distilled water.
100 c.c. of H H2804 were added from a burrette. The solution was boiled
for five minutes to expel the 002. It was then titrated against .1 N
RaOH'using four drOps of methyl red as indicator. Correction was made
for the temperature of the acid. The equivalent of total alkali, ex-

pressed as per cent, Ra2C03, was calculated from the formula:

14

0.0. :1 II IIaCH)

 

0.0. J H2304 (corrected) -

 

Weight of Sample

 

Total Alkali Expressed as Nago (l9) Eguivalent of total alkali

 

F'
2005 X 0 o 084:9 o

Sodiuijicarbonate (fiaHCos) The same method was used as in neutral

.4.,
expressed as pua

 

sodas.
Sodium Carbonate (NaZCOS) (19) The per cent of HaZCOS was calcu-
lated from the formula:

Equivalent of total alkali expressed as 353612003 - (greases x 0.6309)
Super Alkalies.

Preparation 23 Sample (19) ‘A sample was prepared for analysis by
washing about 40 grams of the cleaner into a 500 c.c. graduated flask
with distilled water. The solution was cooled to room temperature, di-
luted to the 500 c.c. graduation and thoroughly mixed. Aliquot portions
of the solution were used for determinations.

32:99.}. Alkali (NaZO) (19) i; 25 c.c. aliquot wee titrated with

NH280 using methyl orange as indicator. The per cent of NaZO was cal-

4

culated from the formula:

0.0. N H280 x 62

4

 

Height of original sanple

 

Sodium.§ydroxide (NaOH) (19) One hundred c.c. of 3&012 was added
to a 25 c.c. aliquot of the prepared solution. This was titrated with
5301 using 6 drOps of phenolphthalein as the indicator. The per cent

of neon was calculated from the formula:

 

15

Weight of original sample

 

Sodium Carbonate (Nazcosl (19) The per cent of Na2003 was cal-

culated from the formula:

(finezo - 35st x 0.7748) x 1.7097.
Tri-sodium Phosphate and Colloidal.

Tri-eodium PhOSphate (HasP04) (20) The method followed in the

 

determination of tri-eodium phosphate was the gravimetric method as

given in the A. 0. A. 0. Official Methods of Analysis for P30 . An

5

aliquot of the solution corresponding to .20 gram was neutralized with
10 - 15 grams of amonium nitrate. 7O c.c. of molybdate solution for
every decigram of P205 present was added to precipitate the phosphoric
acid. The mixture was digested for an hour at 65°C, and then filtered
and washed withcold water. The precipitate on the filter was dissolved
with armonium hydroxide and hot water. Hydrochloric acid was added to
nearly neutralize the solution. While stirring vigorously, 15 c.c. of

magnesia mixture for every decigram of P 0 was added drOp by drOp.

2 5

After 15 minutes 12 c.c. of concentrated 1311403 was added. The precipi-
tate was allowed to settle over night. I The mixture was then filtered,

and n‘shed with dilute 1514011 until freed from chlorides. The precipi-

tate of magnesium pyrp-phOSphate was ignited to whiteness, cooled and

16

and weighed. Calculations were made in terms of.P205, lIa5P04, and Has
P04 .12 H20. The commercial tri-sodium phOSphate used in cleaners con-
tains 12 molecules of water of crystallization. As it stands in contact
with air some of the water of crystallization is given off. Calculations
in terms of Na31’04 12 H20 were invariably high due to this evaporation as
the samples aged in their original containers. Because of this unavoid-
able defect in the analysis, calculations in terms of NasP04_and P205
were found to be more accurate and comparable. The following formulae
were used in the calculations:

Wt. of 11221920? x 1.4731 equal wt. of Na$1>04

{(wt. of NasP04 e .2) x 100 ’ equal 35 Na3PO4

TVt. of ngszO.’ x 3.4146 edual wt. of M31304 .12 H20

{(wt. of Na3P04 . .2) x 100 g equal %Nagpo4 .12 H 20

Wt. of Mgzalfiao7 x .6388 equal wt. of 1320‘5

{(wt. of P205 e .2) x 100; 6C1ual (@205

To__t__al _A_1___kali (118.20) The same method was used as in neutral sodas.

m Carbonate (M2003) Cleaners containing tri-sodium phosphate
were analyzed for carbon dioxide, using carbon dioxide apparatus devised
by the Michigan Agricultural Experiment Station. .25 gram of the sample
was weighed into a small glass container. 1 c.c. of dilute H01, contain-
ing one part 1101, one part water, and 2 drape of anvl alcohol, were placed
in e. 20 c.c. glass bottle, together with the sample. This container was

placed in an upright position. The bottle was connected by a rubber stap-

per and glass and rubber tubing to a graduated tube holding 50 c.c. of

l7

distilled water. The graduated tube was connected with a constant
overflow apparatus. The glass container with the sarple was tipped
over into the HCl. The number of c.c. of water diSplaced by the lib-
erated CO2 was taken as the number of c.c. of CO2 in the sample. Cor—
rections for temperature and barometer readings were made. The per
cent of nazcos in the sample was calculated from the CO2 content by
the formula:

2.41 x grams CO2

 

05'
eh.)

Sodium Hypochlorite (NaOCl) (21) The method followed in the

 

determination of flaOCl was that used by Treadwell and Hall for the
determination of hypochlorous acid. Five grams of the cleaner was
dissolved in 500 c.c. of distilled water. Ten c.c. of 10 per cent
KI solution.was added to a 25 c.c. aliquot of the cleaner solution.
The solution was slightly acidified with HCl. The iodine set free
was titrated with .1 N Nazszos. The per cent of NaOCl in the sample

was calculated from the formula:

c.c. .1 w I-rsgsgo:5 1 .003725
' x 100

 

.25
Free Alkalinity.

A pH determination was made on all cleaners to determine the
correlation between the titratable or total alkalinity and the free
alkalinity or hydroxyl ion concentration. La Mbtte indicators and
cOlor standards were used for the tests. pH on one per cent solus

tions was found by weight.

18

Solubility Tests

Tests were made on each cleaner to determine the relative per
cent of total solubility in distilled water at room temperature.
200 0.0. of distilled water was placed in a. beaker. An excess of
cleaning powder was added to the water and thoroughly stirred. The
mixture was allowed to stand undisturbed over night. 25 c.c. of the
clear solution was transferred with a pipette to a weighed porcelain
evaporating dish. The dish with the solution was weighed and the
weight of the solution calculated by difference. The moisture was
allowed to evaporate and the residue dried slowly in a vacuum oven
to a. constant weight. The weight of the dried residue divided by
the weight of the solution was the percentage of total solubility

at room temperature.

K and Buffer Action Under Dilution

 

 

The pH and relative buffer action of each cleaner under differ-
ent dilutions with distilled and tap water at room temperature was ob-
tained. The pH, which is the value of the ludronl ion concentration,
and commonly called the free alkalinity is also a. measure of the germi-
cidal effect of the cleaner solution. The tests gave the pH at stronger
concentrations than the cleaners are ordinarily used and at different
dilutions up to .l per cent concentration by weight. The ability to

resist change in pH upon dilution is what is coumonly referred to as

19

buffer action. Buffered solutions may be diluted with distilled water
without affecting the pH value. The stability or charge in pH as the
dilution progressed was an accurate measure of the buffer action of the
cleaner when subjected to dilution. This also gave the effect of hard
water on the pH and the buffer action when observations with the same
concentration with distilled and. tap water were made.

La Matte indicators and standards were used in the tests. Solu-
tions were made with concentrations of one gram of powder made up to
100 c.c. with water, 1 to 200 c.c., l to 500 c.c., l to 4.00 c.c., l to

500 c.c., l to 600 c.c.,l to 800 c.c., and l to 1000 c.c.

The Relative mum Powers 9.“. Measured by 1: Drag Number

 

in Benzene and Butterfat

Hillyer (3] advanced the theory that two substances having a low
interracial tension toward each other weuld have high emulsifying powers.
A liquid having a low cohesion for itself and strong adhesion for oil or
grease, will have a low interfacial tension toward the oil or grease and
high enmlsifying power. A liquid having great cohesion and low adhesion
'11]. have high interfacial tension toward the oil and consequent low
Qualifying power. Hillyer (22) devised an apparatus to measure the com-
parative omlsifying powers of different soap solutions toward typical
oils. He compared the number of dr0ps of typical soap solutions issuing
from a capillary tube beneath the surface of kerosene with the number of

drops formed in the same mnner with water. Water forrm large drOps in

kerosene because of its great cohesion and small adhesion to oil. 1
soap solution forms sznall drape because of its low cohesion and its
high adhesion to the oil. Soap solutions issuing from the capillary
will vary in size of drape. According to the theory, those giving the
mllest drops at the same concentration will lower the interfacial
tension mat, and are the best enmlsifiers.

Later investigators have found this method of comparing emulsifi-
ing powers to be satisfactory. Baker and Schneidewind (24) made in-
vestigations in metal cleansing with alkaline cleaning solutions. They
measured the emulsifying power by comparing the size of drape of the
aqueous alkaline solutions issuing from a capillary tube beneath the
surface of typical mineral oils to the size of draps formed in the same

runner by distilled water.

 

A modification of the two methods mentioned was used in this ex-
periment. An apparatus similar to Billyer's was constructed. Figure l
is a drawing of the apparatus. Pure benzene and pure butterfat respec-
tively, were used in the tests.

In benzene the cleaner solutions were made up to .625 per cent con-
centration by weight. All determinations were nude at room temperatures.
With butterfat, it was necessary to reduce the concentration to .02 per
cent by weight. At a stranger concentration the strong alkalies ran
down in a stream and no drape were formed. The tests with butterfat were
carried out at 110° 12“., the temperature being kept constant in a water
bath. The results of both tests were tabulated in number of drape and

the comparative size of draps with distilled water.

 

 

 

APPARATUS FOR MEASURING 7H5 EMULS/FV/NG POWERS
0F CLEANER SOLUT/O/VS

 
     
 

CAP/LLAA’V AIR INLET

 

56cc P/PETTE \

OVEPFLOW

/

PAH/LLARY TUBE /”
6mmD/A: .9m.m. BORE

 

 

 

 

CHAMBER FILLED W/fH “
D’LWZENE 0/? 5077mm r

F/6./

 

 

‘ ,- “J BARNU/‘I—fljfi‘ ‘29‘
W,“ ((H

The Relative Water Softening Powers

 

A portion of the cleaner solution in the washing process is used
up in softening the water. Softening, or the removal of the calcium
and magnesium compdunds present in hard water, takes place simultan-
eously with the cleaning process. The effectiveness of the cleaning
Operation is dependent upon the thoroughness of the removal of this
hardness. If the hardness is not removed, thorough cleaning cannot be
accomplished. Some of the alkaline powder is used to precipitate the
calcium and magnesium. The remaining powder is used in the cleaning.
process. The alkaline powders used in cleaning dairy equipment differ
in their ability to soften water. These tests were made for the pur-
pose of measuring the amount of each necessary to soften a given amount
of standard hard water. The methods used were those of the American
Public Health Association in ”Standard Methods of Analysis".

Preparation of Standard Hard Water Solution Eight grams of

 

CaClz .6 320 was made up to four liters with distilled water. This solu-
tion was analyzed for CaO by the following method. Five c.c. of reagent
301 was added to 100 c.c. of the solution. Ammonia water was added to
males the solution faintly alkaline. 25 c.c. of hot 10 per cent ammnium
oxalate was added to the boiling solution. After boiling for twenty min-
utes the precipitate was allowed to settle, filtered, and washed with
warm water and ammonia until freed from chlorides. The precipitate was
washed into the original beaker with hot water and hot H2604 respectively.
The solution was titrated at 60°C. with .111 K M 1904. The number of grams
of CaO in the sample was calculated by the formula.

c.c. .1 N K M N04 1 .0028

The number of grams of Cao or parts of hardness per million was calcu-
lated by the formula.

Grams CaO in l c.c. 1: 1,000,000.

Preparation 2_f_ Standard Soap Solution (23) One hundred grams

 

 

of dry Inn was dissolved in one liter of 80 per cent alcohol. This so-
lution was allowed to stand several days before standardizing. It was
then diluted to five liters with 70 per cent alcohol. Ten c.c. of the
standard hard water solution together with 90 c.c. of distilled water
was titrated with the soap solution. It required 7.1 c.c. of soap so—
lution to produce a permanent foam in the 100 c.c. of hard and distilled
water. By titration it required 1.7 c.c. of soap solution to produce

a permnent foam with 90 c.c. of distilled water. Tie number of grams
of Cao removed by l c.c. of soap solution was calculated by the formula:

Grams CaO in 10 c.c. standard hard water solution
5.4

 

Measuring the Water Softening Powers 23. Cleaner Solutions (23)

 

All cleaner solutions were made up at the rate of five pounds per 100
gallons of water, or a concentration of .625 per cent by weight. Trials
Vere nude in each case to determine the number of c.c. of cleaner solu-
tion required for 125 0.0. of standard hard water, so that not more than
12 c.c., nor less than 2 c.c. of soap solution should be used in the final
‘itration, when a 100 c.c. aliquot of the filtrate was used. If more
than 12 0.0. of soap solution were used the alcohol contained in it would

greatly affect the surface tension and erroneous results would be ob-

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tained. In all cases the total was made up to a volume of 175 c.c.

Cleaner solution.was added to the hard water solution, thoroughly
mixed and allowed to stand over night. It was then filtered and two
aliquot portions of 100 c.c. and 50 c.c. respectively were pipetted off
and titrated with the soap solution until a permanent lather formed.
The number of c.c. of soap solution used, multiplied by the equivalent
of Cao removed'by one c.c. of soap solution.was the number of grams of
CaO left in the sample. All tests were made in duplicate.

Since it was impossible to use the same number of c.c. of cleaner
and hard water in each case, the only comparable method of expressing
the results was in terms of the number of grams of CaO removed per c.c.
of cleaner solution, and the number of grams of CaO removed'by one gram
of the cleaner powder.

The number of grams of CaO removed by one c.c. of the cleaner solup
tion.was calculated from the formula:

Total grams CaO present - total grams CaO left
Number c.c. of cleaner in sample

The number of grams of Ca0 removed by one gram of cleaner powder
was found by dividing .00625 by the number of grams of CaO removed by
one c.c. of the cleaner solution.

It was found that the College Creamery tap water contains 240 p.p.m.
of hardness in terms of Cao. 100 gallons of tap water contains 94.5
grams of CaO. The number of grams of cleaner powder needed to remove

the hardness in 100 gallons of water was calculated by the formula:

 

. .s
e
.
.
.13

u
I - .

 

. a -
.. . ~ v
_ - 1 .

-1- -—

“ a

, 4

‘ w .J
'.

- s n.
I

... \- ~

 

L .
...J

.3
l a

u ..
C. . 1
r
-. -J
1‘ .
.h. -_
L. -

94.5

No. afgrams CaO removed by 1 gram Cleaner

The amount of cleaner solution, hard water solution, distilled
water and soap solution used and number of grams of Cao removed in each

case are given in table VI.

The Effect _c_>_f_ Abrasives _o_n Metals

 

A well known brand of detergent was selected for this part of the
experiment. The original volcadotte, which is the screened and dried
material that makes up a large percentage of the cleanser, was obtained
from the canpany. A portion of this volcadotte was rubber briskly over
the surface of the metal for a period of ten minutes to determine whether
or not the abrasive scratched the metal. This effect was studied under
a ten power binocular micrOSCOpe. The results were tabulated under the

heads of affected or not affected, and the degree of scratching.
The Effect of Each Cleaner 9}}. Metals

Natale

The metals, aluminum, pure capper, pure nickel, tinned capper,
tinned steel, stainless steel, and Allegheny metal were selected for the
test. The metals were out into strips three inches long and one and
seven-eighths inches wide. Each strip was numbered and labeled and a
small hole bored in the center of one end. Each strip was cleaned

thoroughly with carbon tetra chloride, rinsed with water and wiped dry;

:4 .i. ’ .- . ,. ' - ,v
.35. -2.--: )3.» .

bmix‘f'fo 213‘: (1-; '-..‘- . . , . . - .

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, -c.,*,oa 23.2.4” ,... , .

Mississ- o'xe' - .. ; . ,_

 

s'it. 311,: Luci . ' : ', ' . .

n A ,' .
..‘J- J‘s a. u. .- - _ s i ..

... .. . . .. is.

. . .
o. _ . ._,-_
c. . ‘_

26

placed in a vacuum oven and dried, cooled, and then carefully weighed
to the fourth decimal place. A mark was made with a red pencil at the
exact center of each side.
Solutions.

All cleaner solutions were made up at the rate of five pounds of
powder per hundred gallons of water, or .625 per cent by weight.

Method .93 Making the Tests.

 

 

A.pH of the cleaner solution was made. 210 c.c. of the solution
‘was placed in a 300 c.c. lipless pyrex'beaker. One end of a small silk
thread was stuck to the side of the beaker with a gummed label. The
other end of the thread was run through the hole in the metal. The
metal was suspended to the half way mark in the solution'by adjusting
the loose end on the apposite side of the beaker from the stationary
end. After this adjustment was made the thread was securely fastened
to the side of the beaker by'a gummed label. A.glass petri dish.was
placed over the beaker to exclude dirt and dust and to prevent evapora-
tion. The metal was allowed to remain.in the solution undisturbed for
a period of two weeks. This was done witlithe idea of duplicating fac-
tory conditions as nearly as possible over a period of years. The re-
sults showed only the effect of the cleaner on the metal when left in
contact with it without the factors of rubbing or brushing, and expos-
ure to air. Each of the seven metals was subjected to the test with
each of the sixteen cleaners.

Observations were made at intervals to note the effect on the metal

and change in color of the solution. At the end of the two weeks period

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27

the metals were removed from the solution, washed with distilled
water, dried with a cloth, placed in a vacuum.oven, dried and cooled,
and then.carefully reweighed. The loss or gain in.weight was calcup
lated from the original weight. The corroding, pitting, and tarnish~
ing effect below the air-liquid line and the corroding and tarnishing
effect above the air-liquid line was observed and recorded.

The change in color of the solution was observed and the presence
of any precipitate noted. This gave some idea as to the extent of so-
lution of the metal in the alkali. A pH of the final solution.was
taken to determine if there were any correlation between the loss in
weight and change in pH. The stability and the change in.pB also gave
some idea as to the buffer action of the cleaners when exposed to these
metals.

Photographicjfiggi_

Actual size photographs of each.metal were taken to show the effect
of eadh cleaner on each.metal. The pictures were arranged in.arder on
a background and a group picture taken. The photographs are placed in

the appendix of this thesis.

 

 

 

 

 

.
1

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RESULTS OF EXPERILEHTAL WORK AED DISCUSSION
Chemical Analvses

Chemical analyses brought out the fact that some of the cleaners
studied were of nearly identical composition. The others varied con-
siderably. The analyses made possible a division of the cleaners into
five classes according to composition. The types of cleaners included:
modified or neutral sodas, soda ash, causticized or Special alkalies,
tri-sodium.phosphate, and colloidal. This division of the cleaners enp
ables the reader to compare the effects of the different cleaners within
each class, as well as the effect of the different classes as a whole,

with one another. Following is a classification of the cleaners by num—

 

 

ber.
neutral Soda. Special» Tri-Sodium
Sodas Ash Alkalies Phosphate Colloidal
no. Nb. no. Nb. no.
1 5 6 9 16
2 7 10
3 8 ll
4 12
13
14
15

 

The commercial tri-sodium.phosphate used in the manufacture of dairy

cleaners contains water of crystallization. As the cleaners age in their

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v - . A

 

 

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original containers some of this water of crystallization is given off.
Because of this prOperty, accurate analysis for the form of commercial
tri-sodium phosphate (Ha5P04 12 H20), as ordinarily eXpressed, could

not be determined. The sanples were analyzed for phosphorus by precipi-
tating the phosphorus as magnesium.pyro-phosphate. It was thought best

to express the results in terms of the three compounds, II’aEPO4 (anhydrous),
Na3P04 .12 H20, and P205. The amount of water of crystallization given
off affected the accuracy of the results least when expressed in terms of
P205, and most, when expressed in terms of Na3'P04 .12 H20.

A complete analyses of the cleaners is given in.table I. In some
cases the figures given do not total 100 per cent. This was due to the
small amount of undetermined matter and the moisture content. The moist-
ure content will vary in different brands and types of cleaners. All
cleaners when analyzed were in dry powdered form as they are ordinarily
obtained in large bulk containers.

An interesting fact brought out by the analyses fer total and free
alkalinity was the difference in the amount of each found in the differ-
ent classes. The modified sodas were high in total alkalinity, but low
in free alkalinity. The soda ash cleaner gave a similar reaction. The
special alkalies were high in both types. The tri-sodium phosphate
cleaners as a group were low in total alkalinity and comparatively hig

in free alkalinity.

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31

Total Solubility

 

The total solubility of the cleaners studied varied considerably.
By the total solubility is meant the percentage by weight of the cleanp
ing powder in a saturated solution. The lowest total solubility at room
temperature was 11.12 per cent in the case of number 16. This means that
11.12 pounds of the cleaner will completely dissolve in enough water to
make the solution up to 100 pounds. The highest total solubility was
25.82 per cent in the case of the soda ash cleaner. Under ordinary conp
ditions it would not be necessary to make a washing solution stronger
than one per cent by weight. All the cleaners were soluble to 10 per
cent or more, which.insures their going into solution.without much dif-
ficulty. Those cleaners with high.solubility appeared to go into solup
tion.more readily than.those with lower solubility.

The modified sodas were very nearly identical in their percentage
solubility and were next to the soda ash cleaner in total solubility.
The special alkalies were third in.total solubility. The members of
this class varied more in this preperty than the modified sodas. The
tri-sodium phOSphate cleaners were more variable in their solubility
as a class than the others. This variability ranged from 11.13 per
cent with cleaner number 15 to 24.80 per cent in the case of number 11.
The colloidal cleaner, number 16, bad the lowest percentage of total

solubility. The results of the solubility tests are given in table II.

as}; ;.i-i 11105 I 1J0? Jusfii,
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Table II 0

Showing Weight of 25 cc. of Saturated Cleaner Solutions; Weight of
Dried.Povder Contained in.25 co.; and Total Solubility in Per Cent

at Room.Temperature.

 

 

()1
I“?

 

'Cizaner ‘Weight'of' Weight 0?? Total
Eb. Solution. Dried Residue Solubility
Grams Grams Per Cent

1 29.2612 7.1176 24.32

2 28.7528 6.8531 23.83

3 28.7736 6.6352 23.06

4 29.6700 7.2176 24.33

5 30.4961 7.8754 25.82

6 29.9479 5.9232 19.78

7 31.5569 7.0649 22.39

8 29.8707 5.8185 19.48

9 27.3880 4.8764 17.80
10 26.5294 4.4279 16.69
11 29.2322 7.2496 24.80
12 27.2770 4.5205 16.57
13 28.4501 6.5873 23.15
14 28.7074 4.5447 15.83
15 26.5868 2.9597 11.13
16 27.7738 3.0872 11.12

 

lfi

1:0

u
01

£11 and Buffer Action Under Dilution.

 

 

The pH value of any solution, as has been explained, is the meas-
‘ure of its l ion or 0H ion concentratiOn. In the case of alkaline
cleaner solutions this test is a measure of the free alkalinity. This
free alkalinity plays a disputed role in the washing process, especially
in regard to its germicidal effect. From.this standpoint, the constancy
or change in pH of the solution from concentrated to very dilute form is
a direct criterion of the extent to which it would be advisable to dilute
the washing solution without seriously affecting its detergent value. The
ability to resist change in pH as the dilution progresses is a measure of
the buffer action, or the extent to which the solution is buffered. A
solution in.which the pH is not changed or but very slightly changed
after a series of dilutions is highly buffered. One in which the pH
value is lowered considerably upon dilution is not highly buffered. It
seems correct to state that all cleaner solutions should be highly buffered.

A marked similarity in the pH and buffer action of cleaners of the
same class was noted. The effect of hard or tap water on the pH as com-
pared with distilled water, was a feature brought out by the tests. It
was rather interesting to observe the difference in the pH and buffer
prOperties between cleaners of the different classes.

The results of these tests are given in table III. The table is
self explanatory. It will be observed that cleaners, numbers 1, 2, 3,
and 4 were very similar and constant in their pH and buffer action. In

distilled water cleaner number 1 lost .6 pH by increasing the dilution

‘4-1

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ten times. This was the largest variation in tap water. Cleaner

number 4 exhibited a pH of 9.2 at 1000 dilution which.was the lowest.
Number 5, the soda ash cleaner, remained quite stable and constant

in all dilutions. Numbers 6, 7, and 8, the Special alkalies, contained

the greatest amount of free alkalinity of all the samples on test.

These three cleaners would no doubt contain the greatest germicidal ef-

ficiency. number 8 had the lowest initial pH. here was little differ-

ence between the three when subjected to the other dilutions, or between

distilled and tap water.

The tri-sodium.phosphate cleaners as a group exhibited a wider vari
ation in buffer action than the other groups. The highest initial pH
with distilled water was 11.8 in the case of numbers 12, 13, and 15. The
lowest was 10.8 in the case of Ho. 14. NO. 14 also had the lowest pH of
10.2 at the high dilution. With tap water a greater variation occurred.
The difference in.pH between distilled and tap water up to the 300 dilup
tion was nil in every case except with nunber 11, in which case the vari-
ation was only .2 pH. At higher dilutions the difference became apparent,
being as much as 1 pH in some cases at a dilution of 300. The lowest pH
reached at 1000 dilution with tap water was 9.0 with cleaners number 12
and 14.

The colloidal cleaner was very stable in buffer action in distilled
water. With tap water at high dilutions, the buffer action.was not so
effective. The results of the tests on this cleaner paralleled those

with the soda ash cleaner.

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55

The cleaners may be classified in the order of the amount of free
alkalinity as the solutions are ordinarily used, and the relative sta-
bility of buffer action under dilution by the following. Those showing

least alkalinity and least stability of buffer action are listed last.

Free Alkalinity Stability of’Buffer Action
Class Special Alkalies mbdified Soda
Class Tri-Sodium.Phosphate Soda Ash and Colloidal
Class Soda Ash and Colloidal Special Alkalies
Class anodified Soda Tri-Sodium.Phosphate

 

 

Relative Emulsifying Powers is Measured by DrOp Number and Size

This phase of the experiment is based upon theoretical phenomena
and not on practical tests. Investigators are agreed that the emulsi-
fying power of a cleaning solution is dependent on the lowering of the
interfacial tension between the grease or oil and the solution. A
measure of this lowering of interfacial tension is a measure of the
effectiveness of the dissolved substance or substances used as cleaning
agents.

In this work the method used for measuring the relative emulsify-
ing powers of cleaners was the number and size of drOps of the same vol-
ume of each cleaner solution in'benzene or butterfat, compared with the

number of draps of distilled water.

Shaving pH of Cleaner Solutions under Different Dilutions with Distilled

Table III.

 

i5. 1

and Tap Water.

 

 

 

1-100
1-200
1-300
1-400
1-500
1-600
1-000

1-1000

1-100
1-200
1-300
1-400
1-500
1-500
1-800

1-1000

W W 567 4
Dilutions Distilled Ta}: Distilled TaLDistilled Tap Distilled TEL

10.0 9.6 10.0 10.0 10.0 10.0 10.0 9.6
10.0 9.6 10.0 10.0 10.0 10.0 10.0 9.6
10.0 9.6 10.0 10.0 10.0 10.0 10.0 9.6
10.0 9.6 9.6 9.6 10.0 10.0 10.0 9.6
10.0 9.6' 9.6 9.6 9.6 9.6 10.0 9.4
9.0 9.6 9.6 9.6 9.6 9.6 10.0 9.4
9.6 9.4 9.6 9.6 9.6 9.6 9.6 9.4
9.4 9.4 9.6 9.6 9.6 9.6 9.8 9.2

No. 5 No. 6 so. 7 No. 8
10.6 10.6 12.6 12.6 12.6 12.6 12.4 12.4
10.6 10.4 12.3 12.3 12.: 12.: 12.3 12.:
10.6 10.2 12.1 12.2 12.2 12.2 12.2 12.2
10.6 10.2 12.1 12.1 12.1 12.1 12.1 12.1
10.6 10.2 12.0 12.0 12.0 12.0 12.0 12.0
10.6 10.0 11.6 11.6 11.9 12.0 11.6 11.6
10.4 10.0 ‘11.6 11.7 11.6 11.6 11.6 11.6
10.0 10.0 11.7 11.4. 11.6 11.6 11.7 11.4

 

-1

Kr.

Table III.

(Continued)

Shaving pH of Cleaner Solutions under Different Dilutions with Distilled

and Tap Water.

 

 

 

‘—

“1‘1'67‘9; No. 10 To. 11 MT?
.Dilutions 91.111166 T49 Distilled 15g7946111166 Tap 313111166 _ggg__
11.6 11.6 11.6 11.4 11.6 11.4 11.6 11.6
11.6 11.6 11.6 10.6 11.5 11.4 11.6 10.7
11.6 11.6 11.4 10.4 11.4 10.4 11.4 10.6
10.6 10.0 11.4 10.2 11.4 10.4 11.4 10.4
10.6, 10.0 10.6 10.0 11.0 10.4 10.6 10.0
10.6 10.0 10.6 10.0 10.6 10.0 10.6 10.0
10.6 10.0 10.6 9.6 10.6 10.0 10.6 9.4
10.6 10.0 10.6 9.6 10.6 9.6 10.5 9.0
No. 13 Ho. 14 No. 15 No. 16
11.6 11.6 10.6 10.6 11.6 11.6 10.6 10.6
11.6 11.6 10.6 10.6 11.4. 11.4 10.6 10.4
11.4 11.2 10.6 10.6 10.6 10.7 10.6 10.2
11.4 10.2 10.6 10.0 10.6 10.6 10.6 10.1
11.4. 10.0 10.6 9.6 10.6 10.0 10.6 10.0
11.0 10.0 10.6 9.6 10.6 10.0 10.6 10.0
10.6 10.0 10.6 9.4 10.6 9.6 10.6 10.0
10.6 10.0 10.2 9.0 10.6 9.6 10.44 9.0

1-100
1-800
1-300
1-400
1-500
1-600
1-800
1-1000
1-100
1-800
1-500
1-400
1-500
1-600
1-800
1-1000

 

57

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38

many investigators have used benzene as the drOpping medium in
testing soap solutions. Pure butterfat was used so that conditions
might be made as near that found in dairy plants as possible. It was
found that there was no correlation between the effect of benzene and
of butterfat on the number of the drOps. The fat in milk possesses
great adhesive preperties to metal equipment. Dirt particles also
tend to stick to butterfat very readily. Thus it may be seen that the
butterfat on the surface of the metal serves as a binder to hold the
dirt particle to the metal, as well as being a source of contamination
itself. Therefore, it is desirable to employ a cleaner which will emul-
sify and remove the'butterfat readily, which in turn will carry the ad-
hering dirt particles away in the wash water. Since butterfat is the
predominating oily substance found on dirty dairy utensils, it would
appear that those cleaners having the highest emulsifying powers toward
butterfat would be most desirable for use in cleaning dairy equipment.
Since benzene is entirely absent from dairy utensils and butterfat is
predominant, it appears correct to state that emulsifying tests on but-
terfat are more reliable than on benzene.

The results of the tests are given in table IV. With benzene the
tri-sodium phosphate cleaners as’ a class had the smallest drops. The
special alkalies were next in order, and the modified sodas last. Cleaner
number 10 gave the highest emulsifying powers in benzene and cleaners hump
ber 3: 4. and 5 were the poorest emulsifiers. With butterfat the special
alkalies gave considerably more drops than the others. The SOda “Sh

cleaner and the colloidal cleaner were next, in the order named. The “Dd“

Amino was: 33:13am as: was: at 3:

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Table IV.
Showing Drop Numbers of Cleaner Solutions and Relative Drop Sizes

As Compared with Dr0ps of Distilled Water.

 

Benzene 70U F. Butterfat 1103f.

 

 

Dumber Concentration of Concentration of
of Cleaner Solution .625% Cleaner Solution .02%

Cleaner Dr0p number Dr0p Size ‘_Dr0p Number Drop Size

1 17.5 .886 17.0 .941

2 17.5 .886 17.2 .932

5 17.0 .912 18.5 .865
4 17.0 .912 17.8 .897

5 17.0 .912 29.0 .552

6 18.0 .861 42.7 .575

7 18.0 .861 42.0 .381

8 18.3 .846 45.0 .555

9 18.8 .823 16.0 1.000
10 19.5 .795 15.8 1.011
11 17.5 .895 17.7 .905
12 18.0 .861 16.2 .989
15 17.5 .886 16.0 1.000
14 19.3 .802 15.8 1.011
15 18.0 .861 17.0 .941
15 19.0 .816 18.5 .865
Distilled water 15.5 1.000 16.0 1.000

 

 

 

110.1

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ified sodas as a class were higher in emulsifying power toward butter-
fat than the tri-sodiunlphosphate cleaners. Cleaner number 8 was the
best emulsifier as measured by this test and cleaner number 10 was
poorest.

Chart I is a graphic representation of the relative dr0p sizes of
the different solutions as compared with distilled water in.benzene and

butterfat.

Relative Water Softening Powers

 

The cleaners under study differed in their ability to remove the
soap destroying hardness of water. Table V shows thezimount of hard
water, distilled water, and cleaner solution used in each case to make
up to a volume of 175 c.c.; the amount of Dec present in each case to
be removed; the average nmnmer of c.c. of soap solution used in each
case to produce a permanent foam; and the amount of Ca0 removed by each
cleaner solution.

Table VI shows the amount of CaO removed by one c.c. of each cleaner
solution, the amount of OaO removed by one gram of cleaner, and the number
of grams and pounds of each cleaner necessary to remove the hardness in
100 gallons of tap water having a hardness of 240 pome.

The soda ash cleaner proved to be the most efficient water softener.
The colloidal cleaner, as a class, was next. The modified soda cleaners
were quite consistent in their ability to remove hardness and ranked third

in this respect. as a class. The numbers of the special all-£311 01833 were

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m o a m 9 ¢ 0 N .n voaaapnfiq

 

 

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msofipdaom nossoao no monwm moan obfiusfiom mafiaosm .H cameo

H.H

Relative DrOp Size

i4 .7 _.' ‘I'f-T—I'I'I‘I“Ij‘7”r"f 12:41:11

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very uniform in this ability and were almost as efficient as the modi-
fied sodas. The tri-sodium phosphate cleaners varied quite markedly
from.each other in their ability to remove hardness. Number 14 was
most efficient of the tri-sodium.phosphates and was second among all
the cleaners in its water softening ability. number 10 was least ef-
ficient. The tri-sodium phosphate cleaners as a class ranked poorest
in removing soap destroying hardness.

Chart 11 is~a graphic representation of the number of pounds of
each cleaner necessary to remove the hardness in 100 gallons of tap

water.
The Effect _o_f_ Abrasives on Metals

The abrasive substance or volcadotte does not have the same
scratching effect on all metals. Copper, aluminum, tinned c0pper and
tinned steel are very readily scratched with it. With just a few
rotations of the material on these metals, scratches could be seen
without the aid of the microsc0pe. Nickel was not so readily scratched,
but small scratches could be readily detected without magnification.
All observations were verified under the micr0300pe. Stainless steel
and Allegheny metal were negative to the effect of the abrasive. With
continued rubbing and observation under the microscope, no scratching
effect whatever could be detected. This led to the belief that these
two metals are harder in character than the abrasive substance con-

tained in the volcadotte.

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Table‘v. Showing Preliminary Results of Water Softening Tests.

 

COCO five. C.C. Ave. Grs.

Cleaner C.C.H.W. C.C. Distilled Total Cleaner Soap 301- Cao

 

No. Deed H20 Used Grs. CaO Solution ution used Removed
USed in Titra-
;A_ .625%‘ tion

1 125 15 .09581 35 9.675 .07192
2 125 15 .09581 55 10.800 .06905
3 125 15 .09581 35 9.725 .07175
4 125 15 .09581 55 9.95. .07096
5 125 15 .09581 35 4.625 .08458
6 125 10 .09568 40 7.525 .07683
7 125 10 .09568 40 8.425 .0749?
8 125 10 .09568 40 7.425 _.07732
9 125 .09541 50 8.375 .07472
10 100 25 .07700 50 6.6 .06013
11 125 .09541 50 3.1 .08775
12 125 .09541 50 4.175 .08552
13 125 10 .09568 40 6.575 .07950~
14 125 10 .09568 40 3.75 .08641
15 125 .09541 50 7.55 .07681'
16 125 10 .09581 40 4.4 .08473

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Table 71. Showing Results of‘Water Softening Tests.

 

 

 

Number Grs745357 Grs. CaO Grs. Cleaner Lbs. Cleaner Rank in
of removed removed to remove CaO to remove CaO Water
Cleaner by‘l 6.0. by 1 gr. in 100 gals. in 100 gals. Softening
solution of tap H 0 tap H 0 powers
cleaner 2 2
1 .002055 .5287 287.49 .6557 4
2 .001975 .5156 299.42 .6600 7
5 .002050 .5280 288.10_ .6550 5
4 .002027 .5245 291.59 .6452 6
5 .002411 .5857 245.00 .5401 1
6 .001921 .5075 507.51 .6780 9
7 .001874 .2998 515.21 .6950 10
8 .001955 .5092 505.62 .6740 8
9 .001494 .2591 595.20 .8712 15
10 .001205 .1924 491.15 1.0827 16 ‘
11 .001710 .2757 545.51 .7612 12
12 .001755 .2808 556.55 .7419 11
15 .001587 .2559 572.19 .8205 15
14 .002160 .5456 275.45 .6027 2
15 .001556 .2458 584.45 .8475 14 ‘
16 .002118 .5589 278.84 .6147 5

Chart 11. Showing Pounds of Cleaner Necessary to Remove Hardness in 100 Gallons of Tap Water.

, \\\\\\\\\\\\\\\\\\\\\\\

 

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1.10

1.00

.90

o O O O O 0
CD I‘- «a to 3 n N
o O O O O 0

Pounds of Cleaner

\L\ \1\ \\\\X\\ \\\AQ1 "'

16

12 13 14 _ 15

ll

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05

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Cleaner No.

 

 

 

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7‘7’ 4' f// ,If’“

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Host detergents are made up largely of this abrasive substance.
As a result of this investigation it seems prOper to state that de-
tergents should not be used in cleaning equipment containing the metals
aluminwm, capper, tinned capper, tinned steel, or nickel.

Detergents are quite effective in the removal of some types of
dirt. In.cases where the dirt is baked on to the metal it would be
advisable to use a detergent on stainless steel and Allegheny metal
since the detergent has no effect on these metals. manufacturers (21)
state that Allegheny metal may be scoured without destroying the sur-
face, and that the more it is polished the more resistant it becomes.

The metals are listed in the following table showing the scratch-

ing effect of the abrasive on the metal.

Aluminum 8333
Copper ssss
Tinned Cepper sss
Tinned Steel 833
Nickel 88

Stainless Steel N.E.
Allegheny Metal NtE.
Code: H.E., no effect; a, slightly scratched; so, moderately

scratched; sss, severely scratched; ssss, very severely scratched.

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47

Results 33 the Effect .93 Cleaner Solutions on Metals.

 

Discussion of results shown in tables VII, VIII, IX, and X.

In table VII are shown the individual weight losses of all metals
arranged according to the number of the washing solution used. Table
YII gives the visible corrosion, tarnishing and pitting effect on each
metal by each cleaner. Table IX shows the change in pH of each solution
when exposed to the different metals for 14 days. Table X shows the
change in appearance of the solution after the metals had been partially
immersed in the solution for 14 days.

The weight losses were greatest in Special alkali solutions. The
next greatest losses occurred in tri-sodium phosphate and soda ash clean-
er solutiens respectively. The colloidal cleaner ranked next, while the
modified sodas caused the smallest loss in weight. 0f the metals, tinned
steel suffered the most severe loss of weight in all solutions except in
the case of modified sodas. Aluminum was next in order of weight loss.
Tinned copper lost heavily in the special alkalies, and in mnnbers 9, 14
and 15 of the tri-sodium phosphate cleaners. Capper gained in weight in
contact with the soda ash and special alkali cleaners, due to the oxida-
tion which took place. It suffered the greatest loss in weight in the
colloidal cleaner and modified sodas respectively. Tri-sodium phosphate
caused the least loss of weight on copper. Nickel was comparatively re-
sistant to all the washing solutions, the greatest loss of weight for
nickel occurring in cleaners numbers 4, 7, 12, and 15. Stainless steel

and Allegheny metal were both very resistant to the attack of each wash-

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- ‘ .;’ 71-, A .‘c- new Luis - «2911!- :4:

 

ing solution used.

The corroding effect was closely correlated with the loss in
weight, as may be observed from a study of tables VII and VIII. The
special alkalies caused severe corroding on aluminum, tinned steel,
and tinned cOpper, the extent of corrosion'being in the order named.
The tri-sodium phosphate solutions were next in severity of corroding
effect. Tinned steel suffered the most corrosion in contact with tri-
sodium phosphate, and aluminum was second. Tinned cOpper underwent
considerable corrosion in contact with the three cleaners numbers 9,
14, and 15. COpper and nickel suffered slight corrosion, and stain-
less steel and Allegheny metal were entirely resistant to the action
of tri-sodium phosphate. The colloidal, and soda ash cleaners and the
modified sodas were very similar to each other in their corroding ef-
fect. Aluminum suffered most in these cleaners and tinned steel was
next. COpper, nickel, and tinned capper corroded slightly in most
cases. The three cleaners numbers 1, 5, and 4 did not produce any
corrosion on tinned copper. Stainless steel and Allegheny metal were
entirely resistant to all three cleaners.

The tarnishing effects both above and below the air-liquid line
are recorded in table VIII. The special alkalies produced the most
tarnishing effect. COpper suffered both above and below the air-liquid
line. Below the line cOpper turned black, which was due no doubt to
oxidation. Tinned steel tarnished considerably at and above the line.
Aluminumh c0pper, and tinned copper showed slight tarnishing’by the

Special alkalies. The metals, nickel, stainless steel, and Allegheny

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49

metal were completely resistant to tarnishing by any of the cleaners.
Tri-sodium phosphate solutions caused more tarnishing on tinned steel
than the soda ash, modified sodas, or colloidal cleaners. Exclusive

of the special alkalies the other cleaners caused about the same effect
on aluminum, c0pper, and tinned cOpper.

The special alkalies also caused the greatest degree of pitting,
Alumdnnm pitted most severely and tinned copper next. Tinned steel
pitted slightly. The modified sodas caused slight pitting on alumdnum,
and the three tri-sodium phosphate cleaners numbers 9, l4, and 15 pitted
tinned capper slightly.

Table IX shows the change in pH of each solution caused by the
metals. It may be noted that the tri-sodium.phosphate cleaner solutions
were lowered most in pH. With one exception there was a lowering of pH
in every case. This was greatest in the case of number 9, in which the
pH was lowered 2.4, when the cleaner solution stood in contact with
tinned steel. The special alkalies were next and the colloidal cleaner
third in this respect. The modified soda solutions exhibited the most
resistance to the lowering of pH. In the case of cOpper and tinned cop-
per with modified sodas, a raise in pH was noted. no satisfactory ex—
planation could be found for this except that perhaps the dissolved cop-
per in the sodium carbonate and sodium bi-carbonate solutions acted upon
the indicator in such.a way as to make the solution appear red. If the

pH had lowered, the color of the solution would have been.purple.

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Table X shows the change in appearance of the cleaner solutions.

No change in appearance of any of the solutions after having been in
contact with stainless steel and Allegheny metal could be detected.

All solutions except number 10 changed in appearance with tinned steel.
Aluminum caused the next most visible change. A heavy white precipitate
appeared in.8pecial alkalies in contact with aluminum. Copper caused a
green appearance in the modified sodas, soda ash, and colloidal solutions.
Tinned capper caused a light green color to appear in the modified sodas.

A study of the four tables reveals the fact that there is a rather
close correlation.between loss in weight, corroding, and pitting effect,
lowering of pH and change in appearance of the solution during the test.
Of the metals tinned steel suffered the most and aluminum was almost as
badly affected.

Cleaner number 10, containing tri-sodium phosphate and sodium hy-
pochlorite, caused the least effect of all the cleaners on the metals
studied. Cleaner number 7 exhibited the most destructive effect, altho
it was closely followed by the other two Special alkalies, number 6 and 8.

Photographs of the effect of each solution on each metal are QIOWH
in the appendix. Plate I is a group picture of all the metals showing
the effect of each cleaner solution. The plates, number II to and inn
eluding number XIX, are actual size photographs of the metals showing
the effect of each cleaner solution on each metal. The immersed end of

the metal is the right half, or the end Opposite the number and code on

the metal.

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hbl. VII.
Showing Loss in Weight of Metal Strips in Cleaner Solutions of .625%

Concentration; Partial Immersion for 14 Days at Room Temperature.

 

 

“slim: Aluminum sippeffl‘mwon1 Tinned Tinned steam... Allegheny

 

 

no. Capper Steel Steel Natal
mS' me as me me me me
1 13.4 2.0 0.4 1.9 4.7 0.1 0.3
2 13.1 3.6 0.6 1.8 2.9 0.3 0.2.
3 16.9 2.2 0.4 2.4 4.1 0.1 0.3
4 13.4 3.0 1.3 2.2 2.0 0.1 0.2
6 56.2 4.9. 0.9 1.4 116.1 0.4 0.6
6 216.1 2,2. 0.9 93.4 461.9 0.1 0.6
7 271.0 1.42 1.2 120.2 445.1 1.4 0.4
6 96.3 3,7. 0.7 73.6 319.6 0.2 0.2
9 69.6 1.0 0.6 78.6 219.5 0.4» 0.5
10 63.8 0.6' 0.6 1.0 0.6' 0.6 0.3
11 31.3 0.1 0.1 0.6 210.2 0.1 0.4
12 86.6 0.3 1.6 1.8 121.9 0.4 0.1
13 20.0 0.2 0.6 1.4 122.9 0.2 0.1
14 47.4 2.4 0.7 78.7 199.4 0.1 0.7
16 76.4 1.9 1.0 101.9 316.5 0.1 0.1
16 37.0 3.9 0.3 3.6 0.3 0.6 0.6

__

" Indicates gain in night.

 

7.0

5.0

 

8.0
160
LO

0.0

8.181
0.331
“I
0.618

0.10!

6.0

2.8

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Table VIII.
Appearance of Metal Strips after Immersion in 0.625% Cleaner Solutions;

Partial Immersion for 14 Days at Room Temperature.

 

Home: Aluminum dapper Nickel Tinned Tinned Stainless Allegheny

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rb. Copper Steel Steel metal
t NtE. N.E. t
1 000p 0 0 NQEQ .6? NOE. NOE.
t t N.E. 11.12. t
2 coop o o c To. 11.3. N.E.
t t N.E. t
5 GOOD 0 NOE. .5; Nous NOE.
t N.E. IRE. 151.19.
4 CCCPP o C NOE. 0 NOE. 030
t N.E. tt
5 occpp tttF o N.E. oco N.E. N.E.
t t N.E. t tt
6 occcppp tttt c coop ococp ILE. N.E.
t t N.E. t ttt
7 occcppp tttt o occpp occop N.E. N.E.
8 t NtE. N.E. t ttt
occcppp tttt ' o coopp occcp N. E. II.E.
t N.E. N.E. t ttt
9 oo o o occpp coo N.E. N.E.
__t_ tt N.E. __1_:_ tt
10 cc N.E. o o o N.E. N.E.
t N.E. NtE. tt
11 0° 0 0 N05. 000 NQE. NQE.
t N.E. N.E. tt
12 cc 0 o N.E. 00 11.1%. H.153.
t t N.E. t
13 cop T ' '6'" ms. 000 ms . 11.12.
_t__ N.E. N.E. t tt
14 00 o o coop cco H.E. 11.3%.
t N.E. t ttt
15 cop o N.E. occpp occ N.E. N.E.
t NJ}. H.E. 11.3. 11.33.
16 coop o o o o N.E. 'N.E.
N. E. No Effect

0 slightly corroded; oc corroded; occ heavily corroded; ocoo very
heavily corroded.

t slightly tarnished; tt tarnished; ttt heavily tarnished; tttt very
heavily tarnished.

p slightly pitted; pp pitted; ppp heavily pitted.

The position of the key letter above or below the dash indicates the con-
dition of the metal above or below the air-liquid line.

 

I
o .
o .. ..
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I . U l O . u -m
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U . . . . C —
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a»... a...“ 333 Ina). :2 u
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Table IX.
Showing Change in pH Produced by Metal Strips Partially Immersed in

Gleaner Solutions for 14 Days.

 

Gleaner Tnitial Aluminum Eopper NickelTihned Tinned Stainless Allegheny

 

No. pH Copper Steel Steel Metal
1 10.0 -.4 ..5 o +.5 -.2 o o
2 10.0 -.4 m5 0 «1.5 -.2 0 o
3 10.0 -.4 +.6 o ..6 -.2 e o
o 19.0 -.6 as o as -.4 o o
5 10.6 -.5 o -.5 o -.6 -.5 -.5
6 12.4 -.5 -.2 -.2 -.6 .1.0 -.2 -.2
7 12.4 -.4 -.2 -.3 -.6 -.a -.2 -.2
s 12.4 -.5 -.5 -.3 -.6 -1.o -.2 -.2
s 11.6 .2.2 -1.o -l.6 -1.3 .24 -1.8 -1.5
'10 11.4. -l.6 -1.2 -1.5 -1.2 .1.8 .1.8 -1.e
11 11.8 -1.e -1.3 -1.7 -1.3 4.8 -l.6 ~l.6
12 11.2 .1.8 -.7 ~1.2 -.9 -2.0 -1.4 -1.2
13 10.6 -.a -.o -.6 -.1 .1.0 -.6 -.6
14 10.8 -1.2 -.3 -.s -.s -1.4 -1.0 -.s
15 10.8 -.a -.4 -1.o -.e -1.4 -1.0 -.e
16 10.6 -.s -.1 -.5 -.1 -.s -.6 -.5

 

«I- Indicates raise in pH.

- Indicates lowering of pH.

Table Xe
Showing Appearance of Cleaner Solutions After 14 Days Contact

‘With Mbtals.

 

Dianne: ‘Aluminum dopper Nickel Tinned Tinned Stainless Allegheny

 

Nb. Copper Steel Steel Motel
Light Slight
1 -- Green -- Green White -- ..
Light ppt
2 - Green -- Green very light - --
Green
Light Slight
3 - Green - Green White - --
ppt
Light Slight
4 - Green - Green White - --
ppt
Light Greenish
5 -- Green -- - Yellow - --
Haavy Slightly
6 White -- - - Cloudy - --
ppt
Hbary Slightly
7 White - -- - Cloudy - --
ppt
Heavy Slightly
8 White - -— -- Cloudy .. ..
ppt.
9 Light -- - -- Greenish - --
Blue Yellow
10 - - - - -- -- -
11 ’ Slightly - -- - Light - --
Cloudy Yellow
12 - - - - Light - -
Yellow
13 - -. -- .. L1ght .. -_
Yellow
Very - Light Light
14 - Light Blue Yellow - .-
Blue
Slightly
15 Cloudy - - - Yellow -- --
' modium Light Slighly Slightly
15 Cloudy Green, Cloudy - Yellow - -

 

Note: Where no notation is made, no visible change in the color or ap-
pearance of the solution could be detected.

-_ -un

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C}

COKCLUSIOKS

I. A Cleaners may be divided into five classes on the basis of their
chemical composition. These classes are, modified sodas, soda ash,
special alkalies, tri-sodium phosphate, and colloidal. The cleaners
studied in this work were very similar in composition within each
class. There was no correlation between the total alkalinity, as
measured by titration, and the free alkalinity as measured by pH value.
II. The cleaners were found to vary in total solubility. All cleaners
are soluble enough to go into solution readily at the concentration at
which they are ordinarily used. There appeared to be a close relation
between the rapidity with which the powders went into solution and the
total solubility. By classes, the order of solubility was; soda ash
most soluble, modified sodas, Special alkalies, tri-sodium phOSphate,
and colloidal least.

III. All the cleaners studied were quite highly buffered. In most
cases tap water caused a lower pH than distilled water. The classes
may be placed in the order of their free alkalinity as they are used
under practical conditions; special alkalies highest, tri-sodium phos-
phate, soda ash and colloidal, and modified sodas lowest. The sta-
bility of buffer action was as follows: modified sodas most stable,
soda ash and colloidal, modified sodas, and tri-sodium phosphate least
stable.

IV. There was no relationship between the action of the cleaners as
emulsifiers in benzene and in butterfat. The results in butterfat are

most practical, since butterfat is the oily substance to be removed

from dairy equipment. The special alkalies were found to be the
best emulsifiers of butterfat. The soda ash and colloidal cleaners
were about the same in this prOperty and the modified sodas were
third. The tri-sodium phOSphate cleaners were the least efficient
as emulsifiers of butterfat. Cleaner number 10 was the poorest
emulsifier and cleaner number 8 was the best.

V. Water used f0r washing in dairies contains varying amounts of
hardness. This hardness is due largely to the calcium and magnesium
compounds in the water. A portion of the cleaner is used up to remove
the calcium and magnesium simultaneously with the cleaning process.
The cleaners used were found to vary in the amount of each it took
to remove the soap destroying hardness.

By classes, the soda ash cleaner was the most efficient hardness
remover. he colloidal cleaner was next and the modified sodas third.
The Special alkalies ranked fourth in this reapect and the tri-sodium
phosphate cleaners last. Cleaner number 5 was the best water softener
and cleaner number 10 was the poorest.

VI. The cleaning agents commonly called "Detergents" are made up larg -
ly of an abrasive substance taken from volcanic ash. It was found that
this abrasive substance will scratch the metals, aluminum, and cOpper
very severely; tinned c0pper and tinned steel severely; and nickel mod-
erately. ne abrasive will not scratch stainless steel or Allegheny

metal.

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VII. In the tests for effect on metals when partially immersed in

the cleaner solutions for 14 days, it was found that the Special
alkalies caused the greatest loss in.weight, the greatest corrosive
effect, the most tarnishing and the most pitting. Tri-sodium.phos-
phate solutions caused the next greatest loss in.wei5ht and corrosive
effect. Soda ash was third in weight loss and corrosion. The colloidal
cleaner and the modified sodas exhibited the least destructive effect
on the metals.

Tinned steel suffered the greatest loss in weight and the most
corrosion. Alumdnum was next in this respect and suffered the most
pitting. Tinned COpper was third and coyper fourth. COpper tarnished
the most of all the metals. In the special alkalies the exposed sur-
face of COpper turned black. Nickel suffered slight loss of weight
and corrosion in all solutions. Stainless steel and Allegheny metal
were completely resistant to the attack of alkali solutions.

The pH of tri—sodium phosphate solutions was lowered most in con-
tact with metals. The modified sodas exhibited the most resitance to
change in pH.

There appeared to be a close correlation between the loss in
weight, corrosion, pitting, and change in appearance of the solution.

Cleaner number 10 caused the least destructive effects on the

metals studied and cleaner number 7 was most severe on the metals.

k n

1.

2.

3.

4.

5.

6.

7.

8.

BIBLIOGihll‘HY
Jeremiah 2:22; LIalachia 3:2.

Fall, Paul Henry
Detergent Action of Soaps.

Journal of Physical Chemistry, 31-801, 1927.

Hillyer. He we
0n the Cleaning Power of Soap.

Jour. of American Chem. Society, 25-511, 1903.

Chapin, R. M.
Fundamental Principles of Detergent Action.

Jour. of Ind. and Eng. Chemistry, 17-1187, 1925.

Stericker, William
The Value of Silicate of Soda as a Detergent.

Jour. of Ind. and Eng. Chemistry, Vol. 15, No. 3.

Hunziker, O. F.; Cordes, W. A. and Nissan, B. H.
Metals in Dairy EQuipment.

Jour. of Dairy Science, Lhrch, 1929.

Hunziker, O. F.

The Book of Butter, 2nd Edition.

Phillipe, A. W.; Mack, M. J., and Frandsen, J. H.
Washing Powders for Dairy Use.

Massachusetts Experiment Station Tech. mu. 13. May,

1928.

r.

9.

10.

11.

12.

13.

14.

15.

Taylor, Dr. W. A.
Hydrogen Ion Control in Milk.

Certified Milk, Nov. 1928.

Sherman, Dr. J. M.
Germicidal Effect of Washing Powders.

New York Produce Review, Hay 4, 1927.

l‘hxdge, 0. 5., and Lawler, B. M.

Effect of Alkali Solutions on Bacteria Found in Unwashed mu:
Bottles.

Jour. of Ind. and Eng. Chemistry, Vol. 20, No. 4, 1928.

Levine, Max; Petersen, E. 13.; and Buchanan, J. H.

Germicidal Efficiency of Sodium Hydroxide and Sodium Hydroxide?-
Carbonate Mixtures at the Same H-Ion Concentration.

Jour. of Ind. and Eng. Chem" Jan. 1928.

Runniker, 00 Fe
Metals and Their Various Influences on Milk.

World's Dairy Congress, 1928.

Seligmen, Richard
Milk and Metals.

Proceedings of the World's Dairy Congress, 1923.

Hunziker, 0. Fe
Selection of Metals in the Construction of Dairy Equipment.

Proceedings of the World's Dairy Congress, 1923.

6C)

16.

17.

18.

19.

20.

21.

22.

23.

24.

Guthrie, E. S., and Roadhouse, C. L.
metal Corrosion and metal Flavor.

New Yerk Produce and Am. Creamery. Jan. 2, 1929.

Hunziker, O. F.; Cordes, W. A., and Hissen, B. H.
metals in Dairy Equipment.

Journal of Dairy Science. may, 1929.

Creamery Package Mfg. Co.

Information'by correspondence.

Solvay Process Co.

Solvay bulletins covering the technology of alkalies.

Association of Official Agricultural Chemists.

Official and Tentative methods of Analysis, p. 1.

Treadwell and Hall.
Determination of Hypochlorous Acid.

Amlytical Chemistry, V010 II, P0 5500

Trotman, S. R.
Hillyer's Kethod of Determining Emulsifying Powers.

The Bleaching, Dyeing, and Chemical Technology of Textile

Fibres.

The American.Public Health Association's Standard Methods for the

Examination.of water and Sewage, p. 31, 1917.

'Baker, E. M., and Schneidewind, Richard

metal Cleansing with.L1kalino Cleaning Solutions.

Transactions of the American.Electro Chemical Society, Vol. XLV,1924.

APPENDIX

62.

Plate I. Showing the Effect on Metal Strips of Cleaner Solutions

after Half Immersion for M Days

 

a nan-25:2...
gnu...»
luau.

    

 

 

Plate II.

Showing the Effect of Modified Soda Cleaner Solutions

On Aluminum.

 

63

Plate III. Showing the Effect of One Soda Ash Cleaner Solution

(Nb. 5), and Three Special Alkali Cleaner Solutions on Aluminum.

 

64

P late IV.

 

65

Showing the Effect of Tri-Sodium Phosphate Cleaner

Solutions on Aluminum.

fl
5
‘
a
I
‘.

N0. 12

Plate V. Showing the Effect of Three Tri-Sodium Phosphate Cleaner

Solutions, and One Colloidal Cleaner Solution (No. 16) on Aluminum.

 

66

Plate VI.

Showing

the Effect of modified Soda Cleaner Solutions

'on Copper.

 

Nb. 4

67

Plate VII. Showing the Effect of One Soda Ash Cleaner Solution

(No. 5), and Three Special Alkali Cleaner Solutions on Copper.

 

68

Plate VIII.

Showing the Effect of Tri-Sodium Phosphate Cleaner

Solutions on Capper.

 

69

Plate IX. Showing Effect of Three Tri-Sodium Phosphate Cleaner

Solutions, and One Colloidal Cleaner Solution (no. 16) on Cepper.

 

N00 16

7O

Plate x.

Showing the Effect of Modified

on Nickel.

Soda Cleaner Solutions

 

71

Plate XI. Showing the Effect of One Soda Ash Cleaner Solution

(No. 5), and Three Special Alkali Cleaner Solutions on Nickel.

 

Nb. 8

72

Plate XII. Showing the Effect of Tri-Sodium Phosphate Cleaner

Solutions on Nickel.

 

13.12

Plate 'XIII. Showing the Effect of Three Tri-Sodium Phosphate

Cleaner Solutions, and One Colloidal Cleaner Solution (no. 16)

on Nickel.

    

  

no. 15

 

no. 16

Plate XIV.

Showing the Effect of Modified Soda Cleaner Solutions

on Tinned Copper.

 

Plate xv. Showing the Effect of One Soda Ash Cleaner Solution,

and Three Special Alkali Cleaner Solutions on Tinned Copper.

 

76

 

Plate XVI.

:
:31
n
g,
\.

Showing the Effect of Tri-Sodium Phosphate Cleaner

Solutions on Tinned Copper

 

77

78

' Plate XVII. Showing the Effect of Three Tri-Sodium Phosphate
Cleaner Solutions, and one Colloidal Cleaner Solution (No. 16)

on Timed Cepper .

 

N0. 16

Plate XVIII.

Showing the Effect of modified Soda Cleaner Solutions

on Tinned Steel

 

 

79

Plate XIX. Showing the Effect of One Soda Ash Cleaner Solution

(No. 5), and Three Special Alkali Cleaner Solutions on Tinned Steel.

 

80

O Jab

U

Plate xx.

Showing the Effect of Tri-Sodium Phosphate Cleaner

Solutions on Tinned Steel.

 

81

.(10

r.

0 «lb

Plate XXI. Showing the Effect of Three Tri-Sodium Phosphate

Cleaner Solutions and one Colloidal Cleaner Solution (No. 16)

on Tinned Steel.

 

v

Plate 1211.

Showing the Effect of modified Soda Cleaner Solutions

on Stainless Steel.

 

no. 4

83

Plate XXIII. Showing the Effect of One Soda Ash Cleaner Solution

(N0. 5), and Three Special Alkali Cleaner Solutions on Stainless Steel.

.‘r.

l
f I“)
4 I" r I y

‘

: MM)&JI ‘A' )2 ~

 

84

Plate XXIV. Showing the Effect of Tri-Sodium Phosphate Cleaner

Solutions on Stainless Steel.

 

NO. 12

Plate XXV. Showing the Effect of Three Tri-Sodium.Phosphate Cleaner

Solutions and One Colloidal Cleaner Solution (Nb. 16) on stainless Steel.

NO 0 14-

 

86

Plate Me

Showing the Effect of Modified Soda Cleaner Solutions

on Allegheny Metal .

 

No. 4

87

 

 

Plate XXVII. Showing the Effect of One Soda Ash Cleaner Solution

(No. 5), and Three Special Alkali Cleaner Solutions on Allegheny Metal.

 

No. 8

88

Plate XXVIII.

Showing the Effect of Tri-Sodium Phosphate Cleaner

Solutions on Allegheny metal.

 

89

Plate XXIX. Showing the Effect of Three Tri-Sodium Phosphate Cleaner

Solutions and One Colloidal Cleaner Solution (No. 16) on Allegheny metal.

    

NO. 15

9O

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EN"!