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(III I DRYING WHITE PEA BEANS ‘WITd HEATED AIR By Robert Leo Maddox w ’J ATHEI Submiused to Cue School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the renuirements for the degree of MASTER OF SCIENCE Department of Agricultdral Engineering 1953 run. r’fi '—. l ‘l. wa- IWI7? - “.— ’l .t o . _. , ‘lm'y “‘2 :I.’ :‘S l'. rlvq . .I.|v‘ . - ‘ 'A. k.“ ‘ . s. ' . l.‘ .'fl . 'I 7V '1 . 1‘). . ‘~.“ - up .* . ‘- y.'lf‘u I A 9' - .! p 1'3 4L / z ‘r‘. A CKll CM F Dt’ElalEh TS The author wishes to express his gratitude to Dr. Carl W; Hall for consultation and advice on this project and for his help in con- ducting the series of tests run on the portatle field unit. Acknowledgment is due to William F. Brandt, Investigator on Pea Been Research in the field of drying; to Dr. Herbert Pettiarove of the Farm Crops Department for the loan of the Steinlite Quick Moisture Taster and for his consultaticn on problems of harvesting and storing pea beans; and to Dr. Walter Carleton for suggestions and comments in the preparation of this thesis. Sincere thanks is expressed by the authot to the Commodity Credit Corporation for the financial support that made it possible to carry on this work, and to Judson A. Thompson, Grain Branch of the Production Marketing Association, for his int-rest and helpful suggestions in this project. 317’498 TH {Sis DRYING WRIT? PEA BEANS WITH HEATED AIR By Robert Leo Maddox AN ABsTRAcr Sutnizted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the recuirements for the degree of MASTER OF SCIENCE Department of Agricultnral Enrineering 1953 Approved Mal—gig m W A_ .9 a .. . .hv r u a h . k .a . ‘ a D a 0.. 0 .~, . 4 .‘u e r . o . . a. II.- p , u p a. . a . . .n o . ROBVRT LVO MADDEX ABSTR CT Michigan ranked second in the nation in +otal been production in 1950, 1951, and 1952. Michigan harvested 378,000 acres of edible beans in 1951 and 340,000 in 1952. Michigan harvested 93% (5,782,000 - 100 pound bags) in 1951 and 94% (5,523,000 - 100 pound bars) in 1952 or the total pea bean production in the United States. Michigan also har- vested 55% (72,000 bags) of the dark red kidney beans, 78% (90,000 bags) of the cranberry beans, and 48% (73,000 bags) of the yellow eye beans produced in the United States in 195?. The clima‘ic conditions are such that durinv many falls the pea beans must be harvested above 18% moistlre cuntent. The nature of the pea bean is such that it must be stored at a moisture content of 18% or less, if the pea bean is to remain in an edible condition for any length of fine. It becomes necessary tnsn to remove moisture by the circulation of forced air When pea beans are harvested above 18% moisture content. Although extensive investigations have been made into the drying of various grain crops with both unheated and heated forced air, no investigation had been made into the drying of pea beans. Pea beans differed from other grains in that rapid evaporation of surface moisture caused a shrinking of the bean seed cost and a cracking of the bean. Cracked beans become cull beans so from an economical standpoint it is very desirable to prevent excessive cracking of the pea beans as they are being dried. The Commodity Credit Corporation proposed the partial recirculation of the drying air as a means of controlling the drying rate and preventing ' 1 .1355," y ' l [H «'0‘ I ov- o 'f‘l ‘; a4 - g . . I J; ; I-I ' .3]. Era i a. 'd w. O Q':‘ n ‘ 5‘: ‘I" ROBERT LEO MADDEX . ABSTRACT excessive cracking. A portable field drying unit (bin and fuel oil heater) was loaned to the Agriculilral Engineering Drpartment for use. Five tests made witn this unit used drying air at 1000?. and from 0% recirculation up to 75% recircalacion. Two laboratory units were built, one providing controlled recirca~ lacion and the other providing controlled humidity by introducing steam into the air stream. A total of 26 tests were run using the two labora- tory units with temperatures ranging from 90° to l"U)F., air floss ranging tron 5 c.f.m./bu. to 35 c.f.m./bu., and recirculation from 0% to 75%. Five of these tests were made using controlled humidity (by addition of steam) to regulate the drying rate of pea beans. High percentages of cracking occurred wh-n the tempera+ure of +he drying air was above 1300?. and no recirculation or a low percentage of recirculation was used. The drying rate became slower as the amount of recirculation was increased but the amount of cracking was reduced. Cracking was held to a minimum by controlling the humidity in the air stream. Tests indicated that drying temperatures below 180°F. with a re- circulation of’50% of the drying air, or with drying air having a relative humidity of approximately 15% would prevent undue cracking of the pea beans. ’n-‘oosQ . I '91.- . _ emu-n , I n ' ‘.." ' . new. .. ‘. 5' . .fl :1_ _‘ $I$ TABLE OF CONTENTS Page INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . l OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . 3 REVIEW OF LITERATURE . . . . . . . . . . . . . . . . . . 5 DRY NG EQUIPMENT IN USE . . . . . . . . . . . . . . . . . 13 Farm Driers . . . . . . . . . . . . . . . . . . . . 13 Comnercial Driers . . . . . . . . . . . . . . . . . . l4 Hess Grain Drier . . . . . . . . . . . . . . . . 15 Schanrer Grain trier . . . . . . . . . . . . . . 17 Arid—Airs Drier. . . . . . . . . . . . . . . . . 19 EXPERIMENTAL APPARATUS AND EOUIFMENT . . . . . . . . . . 21 Field Unit Using Recirculated Air. . . . . . . . . . 21 Laboratory Drying Unit for Controlled Recirculation . 25 Drying Unit for Controlled Humidity. . . . . . . . . 30 Temperature Control Equipment . . . . . . . . . . . 36 EETHODS OF TESTING MOISTURE . . . . . . . . . . . . . . 4O STATIC PRESSURE DETERMINATION . . . . . . . . . . . . . . 4S PRESENTATION AND ANALXSIS OF DATA . . . . . . . . . . . . 45 Drying Tests with Field Uni+ . . . . . . . . . . . . 45 Drying Tests Using Laboratory Unit for Controlled Recirculation . . . . . . . . . . . . . 4? Bean Samples Rewet in Laboratory . . . . . . . . 47 High Moisture Bean Samples . . . . . . . . . . . 57 5-. p l'.’.'"v t...\,‘” 'W- .. 'I-u. ~l.., .n‘ I- 7 'q. .. u..o s n 1. .cr‘ .— ~ I ..... n ., 7‘ .".' c - . I - .a- .‘ Page Drying Tests Using Laboratory Unit for COYAtTOIlnd Humidi ty 0 O O O I O O O O O O O O O O C 64 CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . 68 SUGGESTIONS FOR FUTURE INVESTIGATIONS . . . . . . . . . 7O STATUS OF THE FIELD UNIT . . . . . . . . . . . . . . . . 71 SUGGESTIONS FOR DESIGNING A DRYING UNIT . . . . . . . . 72 APPENDIX I . . . . . . . . . . . . . . . . . . . . . . . 73 APPENDIX II . . . . . . . . . . . . . . . . . . . . . . 79 APPENDIX 111 . . . . . . . . . . . . . . . . . . . . . . 8'2 REFERENCES 9 a o e o a o o o a o a a a a e o o o a o O 96 118T OF TANlFS Table Page I Relationship of Grain Moisture Content to Rolative Uuridity of Surrounding Air . . . . . . . . . 10 II Drying Tests Run with Portable FiPld Drying Unit . . . . 45 III Pea Bean Drying Tests . . . . . . . . . . . . . . . . . 48 Figure l. 2. 13. 14. 15. 16. 17. 18. .LIST OF FIGURES Bean Samples Taken From Farm Drying Bins Hess Grain Drier . . . . Schanzer Grain Drier . Arid-Aire Grain Drier. Portable Drying Unit . . Schematic Drawing Showing Arrangement of Drying Bin, Duct, Air Dmnpers, Burner and Blower Grain Sampler Used to Take Been Semplee Laboratory Drying Unit for Controlled Recirculation Schematic Drawing of laboratory Drying Unit for Controlled Recirculation Drying Bin and Heater Section. Measuring Air Flow in Return Duct Schematic Drawing of Laboratory Drying Unit for Controlled Humidity . . . . . . . . . . Drying Unit for Controlled Humidity Heater Section of Humidity Controlled Unit, Steam Entering the Air Duct Thermocouple and Thermometer Used for Determinirz Relative Humidity . . . Obtaining Sample with Tube Sampler Brown Air-O-Line Controller, Grad-U-Motor, Variac, and Magnetic Switchel. . Page 15 16 18 20 21 25 24 35 34 35 35 36 L\. 26. 27. Block Diagram of Air-U-Line Controller and Associated Equipment . . . Tag-Heppenstall Moisture Test-7' . . . . Air Flow Through Clean, Dry Pea Beans . . . . Drying Rate of Pea Beans (rewet} at 5 c.f.m./ft§ Drying Rate of Pea Beans (rewetl at 20 c.f.m./ft§ . Drying Rate of Pee Beans (rewet) at 35 c.f.m./ft§ . . Percentage of Cracked Beans Resultinr from Air Flows of Different Temperatures . Drying Rate of High Moisture Pee Beans at 35 c.f.m./Pt§ Cracking vs. Percent Moisture - Pee Beans . . . . . . Effect of Temperature and Air Flow on Cracving - Percent Recirculation Constant . , , , , , . . . . . . Drying Rate of High Moisture Pee Beans - 15 c.f.m./?t§ Credking V9-‘Tempereruro — Controlled Humidiiy . . . . Cracking vs. Relative Humidity - Field Unit. . . . . Portable Drying Unit with Gas Type Heater. Page 58 42 44 50 51 52 55 56' 58 -1... INTRODUCTION Michigan produced approximately 93% of the pea beans produced in the United States in 1951 and approximately 94% of the total United States production in 1952. Michigan ranked second in the nation behind California in total bean production in 1950, 1951 and 1952. In 1951 there were 378,000 acres of edible beans harvested in Michigan and in 1952 there were 340,000 acres harvested. The average yield in 1951 for xichigan bean production was 1,120 pounds per acre and in 1952 the average yield was 1,150 pounds per acre. Figures furnished by Michigan Cooperative Crop Reporting Service show the total production of cleaned pea beans in the United States in 1951 was 4,072,000 (100 pound) bags, of which about 93% or 3,782,000 bags were pro- dused in flichigan. In 1952 the total United States production was 5,733,000 bags of which about 34% or 3,523,000 bags were produced in Michigan. In addition Michigan produced 108,000 bags or 80% of the total dark red kidney beans produced in the United States in 1951 and 76,000 bags or 55% of total production in 1952. Michigan also produced about 85% or 72,000 bags of cranberry beans in 1951 and 78% or 80,000 bags in 1952, p1us 41% or 60,000 bags of yellow eye beans in 1951 and 46% or 73,000 bags in 1952. The five major states in order of cleaned been production for the past three years are California, Michigan, Colorado, Idaho and New York. Climatic conditions in the western states make it possible to harvest iwans at moisture contents near 18%. In Michigan the climatic conditions '51:: my {a "M’s-O 'h‘. r m. -l‘-I .1 I“ '3?! com". :::;".:i:r fer 1 33:: 01.31., \J 1': ‘cn n. 5.. Ia' . " ..a“ I a ,‘I “*§1 .‘ 'l. 5. fl, ._ “I "' -cl II | .‘_“ ‘ Tina... ’. ””9 :3 3f -2- during many falls make it necessary to harvest beans above 18% moisture content. The nature of the pea bean is such that it must be stored at a moisture content of 18% or less if the pea bean is to remain in an edible condition for any length of timet When beans are harvested above 19%, moisture must then be removed by forced circulation of air through the grain either by 'on the farm' or commercial driers. There are relatively few ”on the ferm' drying systems for handling pea beans and commercial drier installations now in use for bean drying were designed primarily for drying small grain. The use of the commercial eouipment has resulted in high percentages of split beans because forced hot air is applied rapidly. Although the need for fbrced air drying systems for drying pea beans is definitely established, very little information has been available that can be used as a basis for design and selection of eouipment for drying pea beans. -3- OBJECTIVES The almost complete lack of information on drying pea beans made it necessary to first conduct several tests using a wide range of drying conditions. The results of these tests would be used to guide the investi— gations that would follow. The Commodity Credit Corporation had purchased especially designed equipment utilizing the principle of recirculation of the dryhng air at controlled humidity levels. This equipment had been used in a limited number of field demonstrations by inexperienced personnel and, although the principle and equipment appeared sound, extreme difficulty had been encountered by the field personnel in attempting to use the equip- ment. This equipment was made available to the Agricultural.Enpineering Department of Michigan State College for test work. After the first broad objective was achieved usinz the field demon- stration equipment, a laboratory unit that permitted controlled recircula- tion was designed to do fbrther test work. After a number of tests were run on this laboratory unit, a second laboratory unit previously used in a hay-drying project was set up and a series of tests run using this Couipmant. The second laboratory unit made it possible to control the lumddity of the air stream without recirculation. Considering the entire scope of this project, the objectives were: 1. To determine the feasibility.of drying beans by recir- culation of moist air to prevent cracking of the beans. 2. To determine the affect of recirculation on the cracking of the beans. 3. To determine the Optimum percentage of recirculation. To determine cracking and To dotsrmins and cracking To determine the cracking To dstermine -4- the offset of air flow rates on the drying of the pea beans. the effect of tempersrurs on the drying of the pea bssns. ths effect of controlled humidity on and drying of the pea beans. ths ststic pressure required to force the sir at various rstss of flow through the p08 beans at various depths. To provide information to use in the design of s finid unit for drying pea beans. -5“ REVIEW OF LITERATUMB Huch work has been done on the conditioning of grain with forced air, both using natural and heated air. Duffee (l) of'Nisconsin reported on combing and drying grain in 1927 and Lehmann (2) of Illinois reported on drying and shrinkage problems in 1926. The National Research Council of Canada (3) compiled a rather extensive report in 1929 on studies made of the commercial driers being used at that time to condition the Canadian wheat crop. Many of these same driers are being used +oday with little change in their design. Investigations on the drying and storing of grain has centered primarily on wheat and corn; however, the drying of such crops as rise, sorghums, flax, peanuts, ancigrass and legume seeds has been reported in detail. No investigations on the drying of pea beans were reported in the literature; however, many of the basic principles and problems of removing moisture from grain without damage to the grain itself apply to the drying of pea beans and will be cited herein. The problem of controlling the drying rate was recognized early by Duffee (l) of‘flisconsin in his work on the drying of seed corn. Duties reported the recirculation of the drying air and the reversing of the air flow through the drying bins to control the drying rate and the evenness of drying. Investigators who compiled the information for Report No. 24, "The Drying of'Wheat" by the.National Researeh Couneil of Canada (3) state: -6- The data reported support the suggestion that the safe limit for temperature probably varies with the moisture content of the grain. This suggestion is well founded in theory sinee it is well known that proteins beeome more easily changed with inerease in the moisture content. Drying at high temperatures would tend to dry out the outer portions of the kernel while the inner portion was still close to the original moisture content. With deereased evaporation the temperature of the grain itself will tend to rise and the effeet on the inner portion of the kernel will be similar to that in a steam-pressure cooker. The use of lower temperatures on the other hand will prevent too rapid drying of the outside of the kernel and will allow the moisture from the inner portions to be transferred to the outside and driven off. These investigators concluded that there is probably a range of safe drying temperatures depending on the initial moisture content of the wheat, and that wheat of lower moisture content can probably be safely dried at a higher temperature than wheat of a high moisture content. Milling sharaeteristies, loaf volume of baked samples, and official grading of the samples out of the driere were the means of determining the effect of drying on the samples. In 1939 Kelly (4) reported that in drying wheat rapid drying took plaee while the surface moisture was evaporating followed by a slower rate of dryirg depending on the diffusion of moisture from the. inside of the grain to the outside surfaee. Kelly tried applying the heat direstly to the grain and obtained a faster drying rate which he attributed to a greater vapor pressure difference between the inside and outside of the grain causing the moisture to move out. warming the inside of the grain caused the differense in vapor pressure. Kelly used natural air at a temperature of approximately 30°F. as a drying medium. In 1941 Kelly (5) reported on drying grain heated to temperatures in the range of 140° to 145°F. in a revolving drum oven. He found that 57 to 60 parsent of the drying took plaee in the first minute and that 43 pereent of the total temperature drOp took plaee during the first minute. The drying - I‘._}|_' it" 4" H WI“ ‘7‘.» ’I". . fl: ’0 .a 4, n, '-Ie{,. ‘ (.1; a' . 5‘. .1 -7... rate slowed considerably as the temperature of the grain fell. Natural air at temperatures of 78° to 81°F. were forced through the grain. The relative humidity of the drying air was 57 to 61 percent. Several investigators have worked on the problem of drying rice. KcNeel {6) reported that by redrying the rice three or four times at temperatures of 130°F. satisfactory milling characteristics and good germination was obtained. The use of high temperatures to dry the rice down to the desired final moisture content in one operation resulted in weight loss, poor milling characteristics, and poor germination. Many investigators have found that in drying grain there is a 'zone of drying'. This zone is referred to by some as a layering or drying front. When drying air is forced through wet material the air picks up moisture from the wet material in the bin. The drying of the material begins where the drying air enters the bin and moves in the direction of air flow. The air reaches its moisture carrying capacity in a relatively short time of contact with the wet material and will then pass through the remainder of the wet material without absorbing any moisture from it. There is a lower limit below which a material will not give up moisture to drying air if the drying air is maintained at a constant temperature. The drying air then passes through the dried grain and absorbs moisture from the first wet grain with which it comes in contact. There results a zone of transition from dry to wet material which is called the 'zone of drying' and can be rather sharply defined by limits of specific moisture content. .Reporting on investigations in storing grain sorghums Fenton (7) says that the temperature of the grain is of greatest importance in effecting vapor pressure and that the temperature of the grain is the u'rv-mu. - .. .7“ ‘. v.“ *e. greatest single factor in grain drying. Fenton states: Grain sorghums, like other grain, are hygroscopic in nature, in that they gain or lose moisture when the vapor pressure in the space surrounding the grain is greater or less than the vapor pressure exerted by the grain. One of the most complete treatments of basic principle involved in drying grains is given by W} V. Hukill (8). Hukill states: The drying rate for fully exposed grain] is a fUnction of the air temperature and humidity and the grain moisture content. It is affected but slightly by the air velocity. At a given temperature, humidity and moisture content, each kind of grain dries at a characteristic rate, the smaller grains in general drying faster than the larger ones. Hukill says that as air of a given condition is introduced into the grain the rate of drying of the very first grain with which it comes into cormact is influenced very little by the rate of air supply. Tests on exposed drying rates showed that for each kind of grain ex- posed to air of a given wet-bulb temperature the drying rate (a) is independent of air velocity, (b) at a given relative humidity it is propor- tional to the difference between the grain moisture and the eouilibrium moisture content (expressed on a dry basis) and (c) at a given grain moisture content it is proportional to the difference between the dry-bulb temperature of air and the dry-bulb temperature of air in eouilibrium with the grain. As air moves upward or downward through grain of uniform moisture content, the wet-bulb temperature of the air remains constant but the 1The term 'fully exposed grain' is not explained by Hukill. The author believes fully exposed grain to mean clean grain in a drying chamber '° dOOigned that there is a flow of air around all sides of the grain km'"91. In an imprOperly designed drying system there can be dead spots 'w'UIizing in no air flow around some of the grain kernels or uneven air flow around some of the grain kernels. -9... dry-bulb drops approaching a temperature at which the air and grain are in eouilibrium. At any point along its path the rate of evapora— tion seems to be about preportional to the amount by which the dry-bulb temperature exceeds its final eouilibrium temperature. Both Barre (9) and Fenton (7) emphasize that many of the problems of drying grain become clearer when approached from the standpoint of vapor pressures. Vapor pressure differences of the magnitude of 0.05 to 0.10 pounds per souare inch are sufficient for effective drying. Favorable atmospheric conditions may occasionally be utilized to provide suitable vapor pressure differences. Heating a stored grain by using forced ventilation during warm periods and following with cir- culation of cold air can prOVide large vapor pressures naturally. It is often possible to utilize natural atmospheric conditions on such crops as corn that are harvested during the season when sharp temperature drops are most likely to occur. Pressure differences in drying with heated air are obtained by an increase in the vapor pressure of the grain and not by a decrease in that of the surrounding air. Removal of moisture from ‘the grain results because the grain is heated and not because the air is heatod. More heat is needed to evaporate water from grain than from a free Water surface, reports Hukill (10). It is necessary to supply the thtsni heat of vaporization to evaporate moisture from grain. The anusunt of moisture evaporated from grain is proportional to the amount 01? heat supplied to the grain by the drying air. The heat available for 'VBporat ing the grain moisture. is the difference between the init iel dry- bulj; temperature and wet—bulb temperature of the air providing there is “0 14383 or gain of heat to or from the grain through which the air passes. -10.. It is seldom that full utilizaticn of this heat is realized. An English publication (1]) points out that for air and grain at tho lame tamporatur0, a dafinitn r01a+ionahip exists hntw-an tha grain (whoat) moisture content and relativw humidity of tha int-rgrannlar air. Thin relation-hip (Tabla I) is such that a condition of nouiiibrlum exists between the two. Tab}! I shows that with incraaainz atmospheric relative humidity, we get increasing grain mbiatura, particularly whan the relativa humidity is abov- 71%. TABLE I RELATIONSHIP OF GRAIN MOISTURR CONTENT TU RRLATIVR HUMIDITY OF SURROUNDING AIR2 Air Relativo Humidity Gfain Moistura Ccntant 64% in in equilibrium with 14% 71% " " " " 15% 78% n v N " 1 6% 83% " " " " 17% 88% " " ” " 19% 90% " " " " 22% In diacuaaina tho uln of heated air for dryinz train the publication status: Whilo any grain bPint driad is really wot, with say 30% moistura content, fro- evaporation can occur at it; surface: an cuiCkly as surface moi-ture is evaporated more moistura ‘ __ ‘ ziha author assumes this Table is basad on a temperature of 77°F. which in the standard temperature used in computing eruilibrium moisture ‘3Clfl'onts of grain. This fact is not Ita+ed in thc'Enzliah publication. -11... diffusas to the aurfsca from inside. So long as this happens the rate of removal of moisture is constant and is d-prndant not only on the air temperature and humidity but also its velocity. The grain acouiras the mat—bulb temperature of tha air. After a time however, so the grain dries, moisture no longer diffuses to the surface as ouickly as it can be eva— porated. The rate of drying fella continually in proportion to the rasidual moisture still in the train; the drying rate is loss and less depandent on air spend, and tha rrain cannot use all the boat supplied {or fireporation and so its tempera— ture rises above the wa+~bulb value. If the drying capacity of the air is too great during this phase, the outer layers of the train will be baked or 'casa hardened' and the rate of diffusion of internal moisture will be further retarded. If the temperature and volume of the dryina air is too high the train may pat too warm,snd its germination power will be reduced. The shrinkage, which accompani's all drying, may be too fast and the train will aoouiro a shrivelIAd appearanca and will become brittle or even cracked intarnally. Henderson and Perry (12) use the following aou-ticn to darina Oquilibrium moistura curves: .N 1 - rh = «JCTLL rh a equilibrium relative humidity, a decimal M . eouilibrium moisture content, dry basis, percent T = temperature, OR. K,N = constarts (some Constanta are Riven by'HPnderson and Parry) Henderson and Perry point out that the equilibrium moisture curves Ore effected somewhat by a change in temperature, an increase in tempera- ‘btsre shifting the curve downward which zivas a lower rrsin moisture anontent fbr a given eouilibrium relative humidity. ‘Howavar, the affact 1' not sufficiently pronounced to be considered in most enainaerinr work. They state: The aouilibrium moisture properties of materials ara important in storage and drying. If the relativa humidity of the air in contact with a material is hirhar than the aouili- brium relative humidity of the material at its current moistura content, the material will increase in moisture content, the moistura content at th- ralativr humidity baina approached. An air relative humidity lower than the equilibrium will cause the moisture content to decressa. '1’} _:A '. it“; _.,—.'. ‘film'fi" F.5— -13... DRYING EQUIPMENT IN USE Farm Driers In the fall of 1951 several farmers in the Thumb area of Michigan adapted their hay or train-drying eouipment to drying pea beans. As far as the author was able to determine five installations were built using natural air as the dryint medium. There was some question by been growers in the area where the farm driers were built as +o whether or not the beans dried in these drying units would remain in condiiion thrCurh the following spring and summer. In the winter of 1952 the author took a ouart sample of pea beans from two farm drying bins. Both samples were harvested in early October 1951 at close to 23% moisture by elevator test. The drying equipment in the bin from which the sample shown on the left in Figure l was taken was turned on {our times and operated for a total of approximately 30 hours Fig. 1. Bean Samples Taken from Farm Drying Bins —14... during the early part of October. The dryinr eouipment was run for several hours after an elevator test showed the moisture to be just ever 18“. The rate of air flow was approximately 25 to 30 c.f.m./bu. The sample on the rieht in Figure l was taken from a bin where the dryinr eouipment was Operated during intervals of warm weather until the farmer decided by the feel ef the beans that tin moisture content was law enough for safe storage. The samples were placed on a cabinet in an office in the Arricul- tural Engineering Building with the can lids turned down tiehtly and remained there for 20 months. The averare tempersture in the office it was in the neiehborhood ef 72°F. After several months the beans in the jar from which the sample on the rirht was taken beran to discolor and meld growth appeared. Samples from the two jars were dried in the oven in July 195%. The sample on the left in Figure 1 had a moisture content of 14%% while the sample on the rirht had a moisture content ef 20%. On the farm dryinr can be done if the farm operator will follow re- cal‘mended dryine practices and take the trouble to check moisture contents. TWlil information is included here, not frem the standpoint that it was a P‘!“t ef the research work at this thesis problem, but from the standpoint 'f IDeckrreund information of on the farm dryinzo Cemmeroial Driers ‘Eieht elevators ttet were usinr commercial equipment for drying beens ""‘9 visited by the author durine the fall of 1951 and the fall a!‘ 1952. Th1. eouipment was desirned and installed primarily for the dryine ef' wheat or Ctr cern. None of the elevator eperators that the author telked with 'XPP193sed a desire te handle wet pea beans, especially when moisture con- -15.. tents were such that more than twe percent of moisture had to be removed. Hewever, since there are many years when it is impossible ts harvest pee beans at moisture contents safe for lone storaee, the elevator apersters have learned by trial and error how best te use the drying eouipment they have te remeve excess meiature frem pea beans. The three types ef dryine ecuipment abserved are shown in Fi-urcs 2, 3 and 4. These are simplified drawinrs ef the commercial dryinr uniis. The author talked with the elevaier aperater and the person respersible fer eperatine ihe dryine eouipment when visiting eech elevator. Their methed of eperatinr was recorded and is riven on ttr fbllcwinr poses. The methods ef epersiien by the eleva+ers havinr sinilar eouipment were very much alike even theuzh they had arrived at these methods thrcueh their own experience. Other types sf comrercisl dryine ecuirnent may be in use in Michiean elevators which'the author did not visit. Hess Grain Drier. This drier consists of a ceelinp chamber, a heating chamber, e centrifugal blewer, duct werk and steam eeils. The air is pulled threuzh the eeelinr seetien, inta the blower, and passes ever steam ceils befere entering the pressure chambers. The air passes threueh the train seetiens inte exhaust ehambara that either release it ta the eutside er feree it up threueh the heldinr bin that serves as a preheat shamber. The drier is epareted as a bateh drier when it is used fbr pea beans. Reno at the eperaters ef the Bass driers with when the auther talked knew the tem- perature a! dryinr air er the rate at air flew threueh the beans. Dryine was regulated by centrallinr the steam pressure in.the sails and varying the time the beans were in the drying units far different initial meiature sentents. The infernatien recerded an the eperatien a! the Hess drier is as fellewa: -16... P — Pressure E - Exhaust 3 - Suction G - Grain Column I r / gummy. ' ——-————-———J- \df bECTIOH l/\(\\ \‘fikrw””“”t‘"_"’ w l / / / KSTEAM COILS \ \ \ \ '5 L P\LE P E HFATING 3:2 \\ 4/ )1 ’1 / SECTION *- 3:: H w o 0 O \ x \ u x / /———fi 5 G a G I / / / Mfljndp‘Nr ““““ ‘i‘*' f N N \ \ x / A A S 5 ‘ \ \ \ \ COOLING SECTION W ) / / \ N \ \ A A i FIG. 2. HESS GRAIN DRIER -17.. Stoom proosuro - IO pal for boana and 60 pot for oora Oporatod aa - batoh driar with prohoatinz chamber, drying ohambor, and cooling ohambor. Slido doora manually oporatod to control grain movomont. Timo boana hold - 21% hold 20 to 25 minutoa 25% held up to 60 minu+oa Capacity - 50 buahola in each ohamber Percent oracka - notlirible oraakinr occurs with corroot drior oporation; attomptinr to apeed up drylnr by using hither steam prossurea to produoe hither air temporaturv results in craokinr several poroent of tho boans. Schanzer Grain Drier. This driar la operated as a oontinuoua drior. W1mw~m - A.-. Th- unit haa a drying and a cooling ovation and boat ia supplied by an oil burner. The produota of combustion of the fuol oil aro forced throurh tho grain by a aontrlfugal blower and a aooond fan supplies air to tho cooling aootion. A amallor burner is used for dryinr beans than is uaod for dryinr othrr aropa. Tho movomont of tho train through the drier la aon- trolled by varying tho apood of the auger which removvs the grain from th- bottom of tho drying oolumn. Door dampers separato tho heating and ooolinz aaatlona. No prohoatlnz 1a dono with tho moiat warm air. Tho information rooordod on the operation of tho Schanzer drier is as follows: Tomporatura of hoatod air - 115'F. Drlor oporatodraa - aontlnuoua drier Tina roquirod — 21% boana ronuiro 30 to 60 minutoa to dry down to 16%‘mo1aturo aontent D Capacity 400 bushels per hour maximum Poroont oraoka - Operated to give nepligiblo cracking Fuol rato - 3 gallona por hour maximum ~18- GRAIN STORAGE BIN fllum COLUMNS A i/VWARM AIR BLOWER ? F———— l [OIL BURNER — COLD AIR BLOWER L————_.__——~_———-——————-————~—-—d GRA IN AUGEH S FIG. 3. SCHANZER GRAIN DRIER AridnAire Drier. This drier is Operated as a continuous drier. The unit has a heating and a cooling section with the products of combustion being forced thrcugh the grain by a centringal blower. A second blower supplies +he cooling air. An oil burner supplies the heat. A smaller burner is used for drying beans than is used for drying other crepe. The grain is carried through the drier on a horizontal belt. A fire wall separates the heating and ccoling cham- bers.\ No preheating of the grain takes place although the operator of this drying unit suggested preheating of the beans as a method to reduce the cracking occurring in this unit. The information recorded on the Operation of the Arid—Aire Drier is as follows: Tamperature of the drying air - lbOnF. Drier operated as ~ continuous drier with beans 4 inchEs deep on belt Time reouired - 4% moisture removal reouires 1! to 21 minutes, 12 to 15 minutes in heating section and 6 minutes in cooling section. Two runs are made on high moisture beans. Capacity - 7b to 80 bushel per hour removing 4% of . moisture Percent cracks — up to 12% with splits occurring when beans first come into contact with the heated belt. Percentage of cracks becomes greater as moisture goes below 18%. Fuel rate 6 gallons in 10 hours mmHmQ 2325 AmDoDzHBzocv EmH a . A . . . . _ . . . n . - .. s . lo 3F3s..9330a.l3. 3. I'llJIllib.u3tlsl-33 e 3‘ -0313 .33. 336. L .vIIMI-i 3.!ll3§033-l3 3‘39. -. - -. . . .- ,- . . V . 33L 2 ¢ _ . _- . - . _ _ - . . _ A .. . . _ . . - . . .. . . . _ .. . . p .. . . . . . . . . .-_ .... . . . . . . . . F 3 .. . a Q . * . . u r . .. . . .. . - . . T -. . . . . u .. T 3.. .- . .. - . . . - I- . . ,. u L, . . . . _ . _ _ _ . . .- . . . _ . _ 4 fl . . _ . . .. . _ _ . . . u _ _ . . . .. . .. _ _ _ . _ . . -. _ . . . . .1 3. . ... o3..~. - - a . . 3 3 - I: a v . . I_-3l 33333 303......v333l... 3|. .19.. 3 I I v I. 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U _ . .. . . . _ - - . . . . . . .. . ...J .. . . . .. .- ... .. . . . x u f. . .1 -. ....a..- . - ,- . _ _ .. . f _ . n . n, . . . : . . _ . .. . . . . m ...--. ...; .. --. .... .3 ...... .- -J - - I -. m J .. .-.- . - -. .- r - I .-- - + ...- ---...--.--.T......-...-....--3-..33.3-33.-----... 4 . . . _ . _ u . . . _ - _ _. . . .. . ~ . M ~ 0 _ H k . . a . . -_ u h . a .- u . a . w. a it. . a. .N .. < c . o 3 w I I 3 v .. -.~ 4. 3 .HI: 0 a- ..o . . 3 . . _ . . _ . . . . . . . n . . . . . . . . . n . . . . . . m _ _ _ . _ . . . . w p . _ . .- H . -. - ...: a - L-.. - -... .... .. -- - - - .-.- .. 3 .- - -...--- 3-3; :3.- . . . -33 .v-._3- 51-. ...--....-...3-.--- 3»---- 3_--3 - -3 H .. . h u . ., .. . , . _ .0 u . ._ .. . . .M . a ... .. . . .3 . _ H n . . . _ . . _ . . a _ . . . . . . y - ‘ 4 . . ‘ - . . H ,- . - u . . - 3 3 . . - . -h . . . .fi - . 3 3. m- . ..3..- .. .....3 .. ... F. . . 4. A . . d a __ . . . . m _ . H H v _ v - .. s“ W w.- .u .. .*.. ...... t .- . .. . _ _ » . . . . . . _. . . . . . . . 4 _. . -. - . . H , _ . . _. . _ .- . . . . _ . . . . -. - . g - .. _ __ H-o-e .v. ... .33s- 3 u ..o . - .3 .37333feu o ..e 3 .3 N3 d3.- 3... 3 433 f .3 . 3.. 331339-33 9|. 3 .I v -I 3Iv- M33 .7. 3-» 36W.,0..L.-tALA.33.3..v.--P+333fis-Its-«lei .+ I - till. -5 -3. Ad . . . u , - - . . _ .. . - . . . .. . , . _ _ _ — . . . h - . _ . a h r v . , “ w H . _ .. . . » ~ . . . _. . . . . .- . . . . ,_ . . . . . . . . . . _ . . . J . . -. _ . -_ . . w + - , _ . . . 7 .n a _ .4 -. fl _ a _. u ‘ w n m _w ., a ..-3 a 3 . . . . f . . . ... .J- _. 3. .-*-....3 333A --. . e 3 . . if . ...-.- . 93 ... .k3 ..... a.- - . 3 3- . 1‘ D .- .. . _ . . . ~ . . . . ,, . A . w M .. w . . . . . . . . , n . .- .. fl . .. ......- . ,or - . w-. ... a .k H , . . .H “3 . . . . H of... m. m ...-... . . M , _ . _ . . . _ -. ... . W . +. -. .- . . . .. . m _ .0. y ... Out-Q h — _. . .. . .+ .. - . . _ , . .. . .. . u . . . - .. . Afl- , ._. . _ U . . n . 1.. . . \ff . J . fi -. .* . r 3 . . . . . . _V\F.I ‘>0. 3. ..‘I ......l’ r-33s3L33. D3- 31 3.3! ..3.I. 3 .131 __l.3 . .13»). 3. 6.31.3...- .. 3r ...3333b333333lvlrl'n ..3lvl '3ll- b fill-3333F ..... killl.l33ll bl. 333.33.! :3 33333333 In 3. 9 a, 7 6 .... a 5 2 9 A. .1 u c. 4 .d 2 9 8 7 b 5 ... 3 2 1 AIR now THROUGH CLEAN, my PEA BEANS 21. FIG. -45.. PRESENTATION AND ANALYSIS OF DATA Drying Test: with Field Unit To determine the feasibility of drying beans by recirculation of moist air five drying tests were run using the portable field unit, Figure 1. Table II lists the conditions of the five tests. TABLE II DRYING TESTS RUN WITH FORTARIF FIEID DRYIKG UNIT Tent Initiala Finala Air Air Flow Percent Re- Percent No. Moisture Moisture Temp. c.f.m./ft§ circulation Cracks 1 20.0 13.2 102013“. so 0 1'8 bottom 12 top 2 24.92 15.8 IOOOF. 100 50 1.75 3 22.5 16.0 looPF. 100 ‘ Vb 1.25 4 22.4 16.6 98°F. 100 25 2.5 . 3 c..- b . . 5 22.0 18.0 99 r. 100 0 5 bo.tom 1 top u—~ a . . All moisture contents dot-rmnned on ‘wet ba31a’. bEurner on 3 hour, off 3 hour;' The-e tests showed that the recirculation of the moist air reduced the amount of cracking with the least cracking occurring when the highest porcantage of air was recirculated. ‘The time required to remove a percent or moisture from the beans increased as the percent of recirculation in- creased. This in in accord with Kelly (4), Fenton (7), and Barre (9) in their discussion of vapor pressure in relation to drying. Maintaining high vapor pressure in the drying air by recirculation claws the evapora- WTT' -: .F;m.z-.q—-—- ticn cf tha surface wolstfira from ih- b—an and warming {La Deena Geno's a mcr~ rapid iranaf-r of moisfiur~ from inaiJ- cf thfi bean to the cut-isle. The aims surfac' drying pr“.‘.‘-lzib rapid sh‘inking 01' th- skin coat and r‘dD095 rh- cracking. The layering effect as prevlnusly discqase; by +h- author was par icularly agpnranf in th- first drying tear. Th' moistur- conf-nt of samples ia¥~n approxinafaly six inch-z from ihP bsflfcm of {M- Lin approachad t‘z- final WOiSV‘IUYP (firm-r}, 'bnf‘or' Hrr' was much radiaci'ion in the bean sampl-s from th- top cf +H- bin 0r aprroximarnly twenty P‘ iUJhez the bottom cf ih~ bin incrfiaaed rnpidly un+i1 t5“ t-mparaiure of th' incoming heated air was r-aohai WFEIC tampara+urps in +hr top lay'r o the brane inaraaaej very alcwly. As tna i-mP-ra+urn in LIP tcp layav of beans incr‘aa‘d in! vaiaf ron fha bin floor. It was alan rofed thaf tn» temperatura near 9 L iva humidity of th- air l-avinz tha bin n-nama 1058, and tha tnmpnratur. of the air increaafid. This r-lafion of tamparatura and relativ- humidat in in accord with HVPiE1’S'{8) discuazion on the rat- of «vaporation moisturo in relation to tho dry~bu1b t'mpnratures of tha drying air. In the tests made with no recirculafion, morn cracking occurred 3. in the bottom layar of beans than in +he top layar, whil- in th- thra- that: made where racirculation took place thnro was no noficoabl- diff—r-nca between the cracking in th- bottcm and top lay-rs. This was apparnntly due to the rate at which the beans gave Up their moilture to the drying air resulting in a more avcn drying throughout tha dapth of the bnanl. As the vapor pressure differencoa bctween the bean: and th- drying air wore lass where mcilt air was racircu1a+ed, thvrn was a slow-r diffusion of moisture from thn boana to the drying air. This r'sult’d in a mor~ ~47- uniform absorption of moisture from the beans throughout the depth of the beans, and a reduction of cracking. Curves showine tha percent of cracking vs. drying time, temperature of th- b-an lay-rs vs. drying time, and the humidity of tho air loaving the drying bin vs. drying tim' arc included in Appendix I. Thnse curvas, drawn from tho data racorded in the drying tasts listed in Table II, war. pr-pared and includad in tho Research Project P-port for 1951 (13). Drying Touts [Lira Laboratory Unit for Conirclled Recirculation Two series of tests were run usinr this unit. In tr- first series of tosts dry pea bosns (below 16% moisturo) were raised in moisture content and then radried in the laboratory unit. Th0 sPcond sarias of tests were run blihg beans harvested at a high moisturc content. Bean Sample Rewet in Laboratory. The dry beans ware spread out on trays to the depth of l to 1% inchos. The trays were wood fram- with hardware cloth supporting the beans. The trays w-ro placed in an insulated hex. Immorsion heating elements placed in a small, Open water tank main- tained a temperature in this unit in the range of lCSoF. to 115°F. with a relative humidity abc.a 90% providing a high vapor pressure in the chamber. Boans placnd in the chamber for 4 to 6 hours reached moisturo cont-nts as high as 22% although most of the samples that were radried were b-twean 20% and 21% moisture when taken from the insulated box. A Steinlite Moisture Tester was used to give a ouicx check on the meieture content of the beans. Twelve tests, Numbers 6 through 17 in Table III, were run using tho wetted beans. No recirculation was used in these tests, except Test No. 17, as it was desirad to datormine thn effects ‘f drying temperaturas on cracking at varying rates of air flow. A—IK‘D' Ali? «5: - unfiew TABLE III PEA BEAN DRYING TESTS a“ ‘- Him” Test Temperature Air Flow Recirculation R-l. Humidity IQ, .{ Air -°p, c.!.s./Tt. Percent of Dryine Air 1 100 50 o - 2 100 100 50 3 100 100 75 4 100 100 25 5 100 100 0“ 5 90 5 o 7 105 5 o s 130 5 o 9 so 20 o 10 105 20 o 11 130 20 o 12 so 35 o 13 105 35 o 14 130 35 o 15 150 ' 5 o 15 150 20 o 17 150 20 33 13 150 35 50 1a 120 35 50 20 150 35 o 21 170 35 50 22 so 35 50 23 150 35 75 24 150 35 25 25 150 15 33 26 150 15 o 27 100 10 50% 25 100 10 30% 29 140 10 40% 30 14c 10 15% 31 160 10 40% T-Ets l through—5—- fii-ld Unit; Tests 6 5553525 16 - Laboratory‘flnit for Controlled Recircula+ion; Tests 27 through 31 - Laboratory Unit for Controlled Humidity. .Beat on é hour, off % hour. -43.. Figure 2? shows the drying rate usin! an air flow sf 5 c.f.m./ft§ and temperatures ef 90°, 105°, 130°, and 150°F. Firure 23 shews the drying rate using an air [law at 20 c.f.m./Tt§ and temperatures 0f 90°, 105°, 130°, and 1506?. Figure 24 shews the drying rate usinr an air flow or 35 o.r.m./rt? and 90°, 105°, and 13005. The dryinz rats curves by themselves do not present a complete piciure er the drying preblem. The curve, Firure 2?; shewinr the dryinr rate usinr an air flaw of 5 c.f.m./ft§ at 150°F. has a steep slope at the start .f the dryinz but levels out rapidly. This may be the result sf changes within the structure ef the bean resulting in a 'case hardeninr' effect (11). Drying rate curves for oven-dried samples, Appendix II, have a fairly constant slepe indicn+inz a fairly censtant,drying rate a {ram 25% moisture te belew 15% moisture. Using the even drying ret- as a basis, all the curves in Firur‘a 2?, 23 and P4 shew acme effects ef 'cese hardening”. Several beans from the samples taken durins the dryinr tests were out with a razer blade and examined with a marnifyinr glass te see if any physical differences in the creas-sactien ef the bean ceuld be determined that weuld indicate a hardened layer. As far as the auther ceuld see, there was no ring er layer ef greater hardness in the bean cross—sectien. The been crass-sectien had the same physical appearance regardless ef the drying temperature used. Ne attempt was mede te check the chemical structure ef a bean cross—section. More informatien en the drying precess within the bean itself could be of great value in desisninz drying systems. The curves in Figure 22 shew a alewer drying rate when drying air at lSO‘F- and 150°F. was used than when 90. er 1050?. air was used. “q“ , v if: w'fi’Trumk WP . _ .--.1- . ~50- wap\.z.m.c m a< Aamgmmv mz 023555 .a» .lo EHSEE .6: 93mm om _ $935.“; 818 ..moooa 5a sxom x Ina Bu CONCLUSIONS 1. Partial rocirculation of tho dryiur air roducos tho crackina of poa boans. 2. As tho amount of recirculated air is increased for I 'iven Tr:— tempereture and air flow, tho amount of crackinr docreasos and tho rate of dryinr decreases. 3. A dryinr tomporaturo of l25'F. with a recirculation of 50% of the dryine air at an air flow of 35 c.{.m./ft§ are tho optimum condition within tho limits of those tests. As the drying rats is lacrossod by uso of hirhor sir flows the temporaturo will have to bo loworod or a rroeter amount of crackinr will rosult. 4. Tho rate of air flow does not influence the dryinr rate of pea boans noerly as much as the temperaturo and humidity of the drying air. 5. Drying air at temporoturss above lSOoF. causes excossive cracking and should not be usod. 6. Rapid drying of tho pas boans at tho start of the dryin! poriod producod a chonre within tho structuro of the bean. This change rosulted in slow diffusion of moisture from the insido to tho out side of the beam. The lonaor dr'yinr period reouirod to removo tho oxcoss moisture rosultod in more crockine of the beans. 7. Crackinr of tho poo beans occurs through the entire drying _poriod, but increasos in sorority as tho moisture content roos below Poo boans should not be dried to moisture contents lowor +han 13%. necossory for safe storsre to provent crockine durinr dryinr and handling. ~69- 8. Moisture can bo removod from poo bosns Isinr hoatod sir without recirculation if cars is exorcisod in selectinr the temperaturo of tho hootod air. The tamperoturo of tho dryinr air cannot bo as hirh as whon portial recirculation of tho dryinr air is used. Tests indicatod that the temporoture probably should be 20. to 30. store the tomporsture of the beans as thoy are put into the drier. 9. Controlliny tho humidity of the dryiur sir by introducinr stosm into tho sir stroam is a suitable mothod of controllinr tho dryinr rate of pea boans. -70- SUGGESTIONS FOR FUTURE INVESTIGATIONS Furthor invostieations to dotarmine tho rolative humidity of tho air rocuirod to maintain a uniform dryinr rate that would prevent crackin! are dosirahlo. The development of a heated air dryine unit that would permit only a 20. to 30. rise in temperature would be of spacial benefit to tho form dryine unit. A dryinr unit with a limited temperature riso would oliminste many manatement problems that aro present when hieh tomporaturo dryinr air is usod. Investirotions that would show tho procoss of moisture diffusion within the boans and how the moisture diffusion is affected by the temperature and humidity of the drying air, would be of great help in determining Optimum drying conditions. Future laboratory tests should be made in a laboratory unit haviné a cross-sectional area of approximately four souara feet and a bean depth of eight to twelve inches. A unit of this design would permit Inore even drying through the bean depth and a smaller amount of the beans would be dried below 18% moisture where an increase in the rats of cracking occurs. -71.- STATUS OF THE FIELD UNIT The portable dryinz unit that is presently available fbr dryins is shown in Figure 32. The drying unit, which is a direct fired unit, uses #77 _ ...—.47-, - 7 ————————-v—e.—_i Fig. 32. Portable Drying Unit with Gas Type Heater bottled pas as a source of heat. The bottled gas burner is adjustablo fior a wide range of heat output with a satisfactory opera+ine cycle. 'This is possible because of the wide adjustmend on the amount of bottled gas furnished to the burner. One of the main reasons for selecting this unit was the very desirable characteristic that per- mite the wide adfiustment of the total heat output. -72- Sheet metal ducts were fabricated and mounted on the drying unit so that the air supply to the fan could be controlled. Canvas ducts were used between the drying unit and the bin. A more complete des— cription of this unit and instructions for operating the unit are given by Brandt (16). Some changes were made in the drying bin in the fall of 1952 to increase the plenum chamber beneath the perforated floor and to facilitate the unloading of the pea beans. Only one test was run using this urit in the fall of 1952. Excellent conditions for field drying lasted until late October and only a very few wet beans were harvested. No high moisture beans were available for field demonstrations. SUGGESTIONS FOR DESIGNING A DRYING UNIT A heated air drying unit and bin should provide the following condi- tions when designed for drying pea beans: Temperature range - 60: to 1300?. with a maximum variation of 10 at the selected temperature Air flow . — 35 to 100 c.f.m./ft§; speed of fan varied by using a variable speed drive or changing pulleys J Recirculation — Up to 50%; adjusted by manually controlled dampers Drying bin — Column type with a maximum width of 12 inches. An auger type unloading device at the bottom of the column would be desirable. -73... APPENDIX I Curves for Tests 1, 2, 3, 4 and 5, Table III, showing: 1. Percent of Cracking vs. Drying Time 2. Temperature of Bean Layers vs. Drying Time 3. Humidity of Air Leaving Bin vs. Drying Time These tests were run using the portable field unit furnished to the Agricultural Engineering Department by the Production Marketing Administration. The conditions for these tests are given in Table I. -74.. .._m B 28.2 Em ..o 62.5 .._m t 2: m2: 006 onum on“? 00”? omum ooum OmuN OOHN _ a u a _ _ . o... ....om / 1 oc \ n o... "-605 I. 0‘ ...— OOB\ / 1 ON. - 1 on u o¢0\\ /. L r-.. t... a :22... 932...... ...on\ /x. 8 «w... ...... .-....wuww.fl-...e. ....m... .. .8 . .8. 8. 292.5363 2:5 mz>mo - - ..- . ...... _ _ q _ _ ... _ .. ...... I ou oc . 8 0“ \II \ at as. \. . on .\ - Ill: - - 8. 5m .0 Eozom _ m - _ m m _ _ o . l * N— m. on ._VN AJJOINnH 3M1V'138 ‘lo :10 VBUMVUBdWBJ. ONIflOVUO ‘l. m on O? on em Oh co co co. ON ov 0m 00 oo. if... flirt...ikl_y MEI. OOH. OmnN. CONN. on“ : OOH: Omu0_ DOUG. Omum 00.. \l‘ / I I] . / . .J. /, - / 2 J / . 2/ t I \ I.“ Hmmgow . 4.] . / lull-I‘I ll ..-. .... .mm.3.3 ...; cos . u- .... .. .56. .. Azofiqsaomawm $.09 .. A .,-nm2sK.m.m. ......>>.m0 1L . “flair... . a a _ a _ _ that. ..a ...-c : 37.. H / \ . / a o \ II /a \ n .IIIlI / . \ . \lEm yo a2. . \ . ul / I‘IIII. u \ . \ . Em yo .Elotom .. 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Q n‘IInIIIIII‘I-I o D Em »o Eozom 8.4. fl . _ . _ _ . _ o .l. n O a v 0 \ x 9 -78 - 1 1 F 11 014.1 NJIHIJJIIIlII'I-II'JI ll 1 . m2: on; 00... 8.5. 09.0.. on... oo... oflo. oo..o. owm 09m . _ A o _ A . q _ _ . /......o zo\ / to 20 .....o 20 .....o zo .....o 10¢ O {D / , . - . . /.. . . , _ \ /.\ /.o\ o / \ / vl‘\/./.\o\/.\/I/.\~ l O a) Alla! WflH BAUV 138 “/o .11-.....me 1514-54.“... 11111111.. 1. 8. 111 .1. 1.1.5.151; 8: . .- ... -441... ...-......“ x N: .....o .m: N: zo «mama. - mzqmm ”>412 nemfifi 1. ’3 A. t .0 1. |. 1 ‘ill'i-’ I I|-11._r. h m _ _ . _ _ _ _ .. _ . ”c m . .._m .5 ...o»\11 .. \ . \ 1 m \ . \ / . \ . 18 u - . I ( C .\ s \ . l . \ low N . n 1. o» a 3 1 on . O Em .o 62.8 mom a. 1. oo. o .. . . _ 111.. 11 _ -1I1._|1|._ .III._I1I.._./. 1l1 cats.» 1\ 1m w In W m .._m ._o 52.8 o ... n 1 m -79.. AP}? NDIX II Ihy.ag Rate Curves for Ovvn Samples The data used for drawing these curves was obtained by C. W. Hall by drying pea been samples in the laboratory ovvn. These curves 9r! includfid in this thesis for purposes of comparison with curves obtain-d by drying samplPs in th9 laboratory drying units. .mmI NEE. OZ_>mO mm mm mm .VN ON m. N. m 5 . w n v1 1v. . $1 -no- mm .24... . .1520 .._.mmo m4 uo~.N dim... zm>o NEE. 02.>mo .m> HZMPZOO mePmLO—z mz>o FZMono mmakmLOS m1 o .2, .m._.> 9?. Moisture % “racks Bottom Top 10:55 22.7 .7 11:10 18.2 9.6 11:25 17.8 11.2 11:40 17.0 11:50 14.4 24.1' c Only one sample taken at top. ~91- TEST NO. 22 Nov. 28, 1952 Air Flow 35 Qéfdn,/ft? Room Temperature 70°F, Drying Temperature igoop. Re1a+ive Humidity 27% Recirculation 50% Time 7‘ Moisture “.3 Cracks -Bottom Top 2:05 22.8 .7 2:20 20.5 1.8 2:35 19.4 2:50 18.0 2.0 3:05 17.9 3:20 17.3 2.6 3:35 16.9 21.5 TEST N0. 23 Nov. 29, 1952 Air Flow 35 c,f,m,/f+? Room Temperature 65°F. Drying Temperature 150°F. Re1ative Humidity 21% Reoirou1ation 76% Time . % Moisture % Cracks Bottom Top 3:00 22.4 .7 3:15 18.3 5.3 3:30 16.0 6.1 _5:45 15.5 23.5 Nov. 30, Air Flow Drying Temperature 1952 Recirculation Dec. 17, Air Flow Drying Temperature Time 3:35 3:50 4:05 4:20 1952 Recirculation ‘G‘j’. -:-. .‘l-m n Time 2:50 3:05 3:20 3:35 3:50 14:05 4:20 4:35 4:50 TEST NO. 35 c.f.m./ft 150°F. 25% 3 24 ‘7. Mois ture Bottom Top 22.3 19.2 16.0 15.0 2 TEST N0. 25 15‘c.f.m./ft? 150°r. 33% 1 Moisture Bottom 22.8 22.9 22.6 22.2 21.8 24.1 23.7 22.9 18.7 _ h..a tn vet sample. Top Room Temperature Relative Humidity 25% Room Temperature Relative Humidity 2&3 -92.. 65°F. % Cracks .4 4.7 11.5 68°F. % Cracks .7 ‘flp_ , a 1.! Dec. 17, 1952 Air Flow Drying Tempera+ure Recirculation ' Time: 9:35 9:50 10:05 10:20 10:50 11:05..' TEST no. 26 15 o.f.m./,t‘t§ 150°r. 0% ’5 Moisture Bottom Top 23.0 23.1 22.5 22.9 22.7 21.7 -93. 3297.1 Tamra“: 67°F. Re1a+ive Humidity ~ % Cracks I E T“ 5 .7 ;f w 1 £11.“ E r 1.7 tBin emptied; sempie taven 2" above floor. Quite a few creckad beans next to perforated floor. April 2, 1953 .Airflon , Drying Temperature 0.13, 100*, 77.3. 84° Air Stream R.H. 50% Abo. H. .023 Time 9:00 9:30 10:30 11:30 12:30 *D.B. - dry bulb; W.B. - wet bu1b; R.H. - Relative Absolute Humidity. TEST N0. 27 . % Moisture.. Bottom Top 21.2 23.5 21.7 21.1 21.1 Room Temperature 65°F. R.H. 57% Abo. H. .005 ‘1 Lracks .7 .7 Humidity; Abo.H. - TEST EU. 28 April 3, 1953 Air Flow 10 c. ram/1‘2 . Drying Temperature D.B. 100 2., wua. 74.2°F. Air Stream R.H. 30% Abo.H. .013 Time % Moisture! Bottom TOp 10:00 21.5 12:00 21.1 1:00 20.2 3:00 18.3 TEST NO. 29 April 9, 1953 Air Flow 10 c.r.m./rt? Drying Temperature D.B. 140°F.,‘W.B. 1120?. Air Stream R.H. 40% Abo.H. .052 Time ' % Moisture Bottom Top 10:45 21.5 11:45 23.9 12:45 22.4 1:45 20.5 ’94- Room Temperature 65°F. Relative Humidity 58% % Cracks .7 Room Temperature 73°F. Relative Humidity 57% % Cracks .7 .8 .8 .8 TEST N0. 30 April 10, 1953 I Air Flow 5 10 c.f.m./ftf Room Temperature 66°F. Drying Temperature 0 Relativa Humidity 48% D.Bo 140 F.,'W.B. 90 F. Air Stream 8.8. 15% Abo.H. .019 Time % Moisture % Cracks Bottom Top 7:30 21.3 .7 8:30 19.8 1.0 9:30 16.3 3.0 TEST NO. 31 April 10, 1953 Air Flow 10 c.f.m./ft? Room Temperature 70°F. Drying Tempgrature o Relativ- Humidity 50% . D.B. 160 F., W28. 126 F. : Air Stream R.H. 40% g Abo.H. .09 I Time % Moisture % Cracks Bottom Top 12:30 21.3 .5 1:30 22.7 1.4 2:30 a 21.3 4.3 3:30 20.5 5.7 REFERENCES 10 mff‘“, F. “0 Results of Combining and Drying Grain. Agricultural Engineering Journal. 8: 55-57. 1927. 4—7 "‘ 2. Lthann, E. W. Grain Storazr, Dryinr and Shrinking Problems. Agricultural Engineering Journal. 7: 269-270. 1926. , i , 3. Anon. : The Drying of Wheat. National Research Council, Dominion of 5 Canada. Report No. 24: 42-44. 1929. ‘—- g 4. KP] 1y, C. F. Methods of Drying Grain on the Farm. Agricultural Enpineerinz 5. Kelly, C. F. Drying Artificially Heated Wheat with Unbeated Air. Agricultural Engineering Journal. 22: 316-320. 1941. '— 6. McNeal, Xzin. Artificial Drying of Combined Rice. Agricultural Engineerinz Journal. 28: 62,67. 1947. _—~ 7. Fenton, F. 0. Storage of Grain Sorghums. Agricultural Engineering Journal. 22: 185-188. 1941. 8. Hukill,'fl. V. Basic Principles in Drying Corn and Grain Sorpbums. Agricultural Engineering Journal. 28: 335-338. 1947. 9. Barre, H. J. Vapor Pressures in S+udying Moisture Transfer Problems. Agricultural Engineering Journal. 19: 247-249. 1938. 10. Hukill, W3 V. Types and Performance of Farm Grain Driers. Agricultural Engineering Journal. 29: 53-54, 59. February 1948. 11. Anon. The Drying and Storage of Combine Harvested Grains. Muntona Limited, Bedford (England) and Edward Piaon Limited, Ipswich (England). p. 14. 13. 16. 17. -97- Henderson, S. M. and Perry, R. L. Engineering Elements of Agricultural Processinp. Edwards Brothers, Inc., Ann Arbor, Michigan. pp. 149-150. 1952. Hall, C.‘W. Drying of Pea Beans wirh Heated Forced Air. Research Project 410. Agricultural Engineering Department, Michigan State College. 1951. (Unpublished). Severus, W; H., and Degler, H. E. Steam, Air and Gas Power. Ed. 4. John Wiley 8 Sons, Inc. New York. pp. 399-4010 1948. Brandt, 1". F. The Use of Ozonated Air for Excess Moisture Removal in Stored Grain. Thesis for M. S. Degree, Department of Agricultural Engineering, Michigan State Collare. 1952. Brandt, W} P. and Hall, C. W} Drying of Pea Beans with Heated and Recirculated Air. Research - Project 410. Agricultural Enrineering Department, Michigan State College. 1952. (Unpublished). Blynka, 1., Martin, V. and Anderson, J. H. Comparative Study of Ten Elecirical Meters for Determinine the Moisture Content of'Nheat. Canadian Journal of Research. 27: 382-392. October 1949. ' ilk-LIBRARY WAN 11111 W