USRE22383E - Art of preserving valuable elements - Google Patents

Description

G. D. ARNOLD Re. 22,383

ART OF PRESERVING VALUABLE ELEMENTS OF ORGANIC MATERIAL Original Filed Dec. 29, 1939 a Sheets-Sheet 1 mam INVENTOR Geemo 2 Hem/.0

M,M#AML ATTORNEY-5 Oct. 5, 1943. ARNOLD Re. 22,383 ART OF PRESERVING VALUABL E ELEMENTS OF ORGANIC MATERIAL 7 Original Filed Dec. 29, 1939. 3 Sheets-Sheet 2 INVENTOR 65260.0 0. lkwaxo 4M MM rToRNEYs Oct. 5, 1943. c. n. :ARNOLD ART OF PRESERVING VALUABLE'ELEMENTS OF ORGANIC MATERIAL s Sheets-Sheet 5 Original Filed 1190,29, 19:59

INVENTOR G'EPPLO O. FHA/04.0

AM A/MJ Reissued Oct. 5, 1943 PATENT OFFICE ART OF PRESERVING VALUABLE ELEMENTS OF ORGANIC llrIATERIAL Gerald D. Arnold, Wauwatosa, Wis.

Original No. 2,266,292, dated December 16, 1941,

Serial No. 311,639, December 29, 1939. Application for reissue August 17, 1942,

33 Claims.

This invention pertains to improvements in the art of preserving valuable elementsof organic materials in dry storage. The present application is a companion to my application Serial No. 231,110 filed Sept. 26, 1938, now Patent NO.

2,241,654, granted May 13, 1940.

The major objects of the present invention are the same as those specified in the companion application above identified, viz; the preservation of color and vitamin A content of herbaceous stock foods during extended storage periods. Specifically, the invention primarily pertains to the removal of what may aptly be termed stored heat. In addition, the present invention seeks to improve the apparatus and method for greater efficiency not only for the retention of valuable ingredients in stock food, but also for the dissipation of heat from fertilizers and other materials.

Heat, sufilcient to cause degeneration, may be imparted to organic material by the atmosphere or it may be generated during the process of cutting, grinding or dehydration. If this heat is allowed to remain in the material during extended storage periods, it promotes fermentation, oxida tion, and enzymetic and bacterial action to the detriment of the product. The present invention, like that disclosed in the companion application above identified, contemplates a process of refrigeration which involves the delivery of the material to be cooled, in a subdivided condition, into a pre-cooled gaseous stream to be entrained and conveyed by the chilled gas while giving up its heat to the gas.

The present invention seeks to improve the chiciency of this operation by recirculating the gas with the objective not merely of conserving its residual capacity for heat absorption, but with the further objectives of reducing difiiculties having to do with condensation on the refrigerating coils and also difficulties involved in the inseparable component of dust which is carried with the recirculated air and which tends to cling to the refrigerating coils if these are moist or wet with condensation.

A further object of the present invention is to provide a means for assuring that relatively heavy particles of roughage in the material to be cooled may be cooled to substantially the same temperature as finer particles or dust.

Another object of the invention is to maintain the device in operation substantiall at full capacity and with minimum power requirements by regulating the input of material and the speed of operation of the fan inversely as the temperature of the gases at the point where they ential can be maintained.

Serial No.

are separated from the material, which has been pneumatically conveyed and chilled. I propose to feed the material to the pneumatic stream as rapidly as the stream can adequately chill the material, and if the temperature differential between the material and the air at the point of discharge has been so reduced as to impair cooling efiiciency I propose, by automatic means, to reduce the rate of feed until the proper differ- Since more air is needed for pneumatic propulsion than is necessary for the performance of the cooling function, I am also able to save power, when less material is fed, by reducing the speed of the fan,'and

it is one of the purposes of the present invention to accomplish this object automatically and con.- currently with the reduction in the rate of feed, the same automatic controls being employed to accelerate the rate of feed and the rate of fan 0 operation when the temperature diiierential between the feed and the air at the point of discharge exceeds the predetermined value. While subject to automatic controls, as above indicated, it is my purpose to maintain the volume and rate of air flow and the volume and rate of material movement substantially constant under normal conditions.

Other objects of the invention will be apparent to those skilled in the art upon examination of the following disclosure.

In the drawings: Fig. l is a diagrammatic View partly in front elevation and partly in section of a pneumatic separating device having my invention incorporated therein.

Fig. 2 shows diagrammatically an alternate embodiment of my invention.

Fig. 3 is a section taken along line 3-3 of Fig.2.

Fig. 4 is a diagrammatic view of still another embodiment of my invention with parts broken away to best disclose the inner construction.

Fig. 5 is a front elevation partly in section of a cooling chamber disclosing an aiternate arrangement of enclosed cooling coil.

Fig. 6 is a cross sectional View of cooling coils which I prefer to employ in the device shown in Fig. 4. V

Fig. 7 is a side view partly in section of an alternate cooling coil adapted for use in the device as shown in Fig. 4. Fig. 8 is a cross sectional View of the coo-ling coil disclosed in Fig. 7. Fig. 9 is a horizontal cross section through the revolving drum taken on line 9 -9 of Fig. 2.

Like parts are identified by the same reference characters throughout the several views.

Fig. 1 discloses a preferred embodiment of my invention wherein a pneumatic stream is circulated by a blower I I through a closed circuit comprising conduit I4, separator I2, conduit I5, air

washer unit 32, refrigerator unit33 and conduit l3.' A material inlet or feed pipe I leads into conduit referred to as the air stream althoughothergas,

such as CO2 may be employed if desired.

My invention further provides for control of the speed at which the blower unit operates in response to air temperature changes in thesame manner in which the rateof'feed delivery is'controlled. Control of' both feed delivery and blower speed is effected through the employment of mechanism which is responsive to temperature changes in the air stream between the point at which'material enters the stream and the point at which the air is discharged into the atmosphere,'or re-cooling of the air 'takcsplaceas the case may be, depending upon whether an open or a closed, circuit apparatus is employed.

In the closed system as shown in Fig. 1, a the!- mostatic control device 24 is employed to govern the rate at which material is fed into the air stream as well as the velocity or intensity of the stream. Control 24 has a heat responsive member 25 disposed within conduit I5 'where "itis actuated by the heat of the air stream-after it is discharged, from the separator and flows toward the recooling mechanism. While I prefer to locate control 24 as shown, I do not wish'to so limit the scope of my invention, it being'apparent that this controlcanbe so placed as to be actuated by the stream before it enters the separator 'oreven during the separating operation. 'Control 24 as herein disclosed is adapted to pneumatically-regulate the operation of associated mechanismflout a control adapted to'regulate associated hydraulic or electrical ,mechanism maybe employed *with equal success.

Compressed air from a source not shown is conducted by means of conduit -2B*through control device "24 and thence to feed control unit 22 and to blower control unit 26. Unit 24 may be of the general type having regulating "means 29. Units 22 and 25 may include constant speed "mo- .tors adapted to drive associated mechanism through variable speed devices controllable by damper motors 28 which are pneumatically ac- .tuable.

I have found that in the cooling of comminuted and dehydrated material or the like, it is economically expedient to employ a closed circuit system wherein the material is fed into the air stream to commingle therewith, whereby the individual particles of said material may be separately cooled by reason of absorption of heat therefrom by the colder gas in direct contact therewith. During the cooling process, the "material is simultaneously conveyed to a separator. The separated gas is then conducted to a'coo-ling or refrigerating unit for removal of the absorbed heat. The re-cooled gas is then returned to the system. In localities where a source .of cold wa e is avai abl st ll iurthcr economies may be gained by employment of the water spray method for cooling the gas, either as the sole cooling means or as an auxiliary means to be employed in connection with other means for artificial refrigeration.

Finely comminuted material may be sufficiently cooled by the apparatus above described in its passage through conduit I3, blower II, conduit I4 and through the vertical path within th sepairator I2. When relatively coarse material is to .be cooled, it .may become necessary to increase thelength of time during which the material is exposed to the cooled air in which case I incorporate a:revolving drum 42, Fig. 3, between the .DOint at which material is fed to the stream and .the point at which it is separated therefrom. When the gaseous stream enters the drum, it expands with .a resultant decrease in velocity, Light particles readily pass through the drum at decreased velocity, but the heavier particles requiring more buoyancy, drop to the bottom of the drum. As the drum revolves, vanes 43 transfer the'heavy-particles from the bottomto'the top thereof, where they slide off the vanes and 'fall through the central portion of the drum. This retarding of theair stream-adds to the efl'lciency of the device in the cooling of either coarse or fine material, because heavier particles which require more cooling, are subjected to the cool air for longer periods of time than'are the lighter particles. Drum 42,'whi1e illustrated only in conjunction with the apparatus shown in Fig. 3, may be advantageously utilized in the devices shown in Figs. '1 and 4. I do not limit the use of the speed retarding drum either to, any specific type of cooling apparatusnor to anyspecific location in respect to other elements in the circuit. '11; 'is apparent that the drum would be equally efficientinconduit I 3 between the feed intake pipe andthe blower I I.

Fig. '1 discloses .an apparatus in which both closed chilling units and water spray are employedto cool and clean the air, whileFig. 4 disclosesan apparatus in which the air washer has I 'been eliminated. Itis apparent that the regulation of the rate of feed and the regulation of the velocity of the air stream in response to temperature changes of gas within certain parts of the system is equally adaptable to either an open circuit or a closed circuit system. I do notwish to limitthisphase of my invention to use inany particular type'ofsystem. a

Referring more specifically to Fig. 1, the material is fed into the throat I9 of pipe III, the

rate of 'feed being regulated by a suitable metering device herein exemplified by rotatable blades '20 which are operatively connected to a source of power 22. Unit 22 preferably comprises la motor 23 and a variable speed mechanism intermediate the 'motor and the metering blades 20, and is responsive to the thermostatic control device 24. As the material is metered through the upper portion of pipe I0, the atmospheric air is excluded, or at least it is limited to a small amount which fills the interstices of thematerial asit is fed in. Apneumatic conveying current or air stream is constantly circulated throughout the device by blower I I which runs continuously. As gravity and suction pull the material down pipe II], it enters the air stream which is flowing through suction pipe l3 in the direction of blower II. The finely divided material is quickly mixed with the air which is moving at a rapid rate and such mixture is accelerated by blower II as the material passes therethrough on its separated way to separator I2 through conduit I4. The air' stream into which the material enters has been previously chilled by its passage through washing unit 32 and refrigerating unit 33 and hencethere is a rapid heat transfer from the *finely'divided particles of material with a resultant rise in the temperature of said air as a result of such heat transfer. Because the finely divided particles of material are individually contacted and cooled by the chilled air, the heat transfer takes place very rapidly. Further heat transfer takes place within centrifugal separator I2 and; in fact, if conduit I4 is relatively short,

much of the heatitransfer may take place within this separator because of the relatively long length of travel of the vortex currents around the inner walls of the separator as compared to the length of travel in conduit I4. By the time the material is separated from the vortical currents -'-within separator l2 to pass downwardly toward the'discharge throat 30 through which it is re- -moved, the temperature thereof has been sub- Dust which escaped the separator is largely precipitated on the floor of chamber 32 as the result of the washing or spraying to which the air stream is subjected in this chamber and it may be periodically removed therefrom. From chamber 32 the air stream is conveyed through conduit I6 to refrigerating chamber 33 where is passes I directly over a battery of refrigerating coils 40 which are preferably under a continuous spray from nozzles 34 for the purpose of washing off any dust which might'still be entrained within the air stream and which would otherwise tend to accumulate on the coils and heat insulate them. The water spray over the coils is circulated by pumps 44 and 45 and is a more efficient means of heat transfer from the air or gas current than if the air is sucked through the coils Without the spray. v

Nozzles 34 are preferably supplied with water by pump 44 which has an intake passage connected to the bottom of chamber 32 to provide re-circulation of the same water over the refrigerant coils- If desired, pump 44 may be thermostatically controlled by unit 24 in the manner in which pump 60 is controlled by unit I24. If

conditions so warrant such an arrangement, pump 45 can also be controlled through unit24. In passing through chamber 32, conduit I6 and chamber 33, the air stream is aided in maintaining a uniform velocity with minimum eddy currents by the provision of multiple arcuate fins 36. Adjacent the outlet passage of chambers 32 and 33 are positioned water eliminators 31 and ,38'to prevent free water from escaping. As the air stream leaves unit 33, it is substantially free from all entrained mist and is at the proper low temperature for starting a new cycle.

Itis apparent that it is undesirable to produce a condition in an apparatus of this type wherein moisture-laden air might give up some of its moisture to comminuted material which has been preferably dehydrated. I have found from actual tests that even where the air stream is saturated, it does not impart moisture to the material. This is du primarily to the fact that the material as it is fed into the air stream causes a rise in temperature thereof and at an increased temperature the air is capable of holding more moisture. The particles of material are warmer than the air and because they are separated therefrom before being cooled to air temperature, they do not absorb moisture, and thus instead of the air stream imparting its moisture to the material, the converse is true and the material is to some extent dehydrated during contact with the cold air.

The exact location of the blower in relation to the other elements of the circuit is unimportant, but if it is undesirable to have the material go through the blower fan, the blower maybe positioned in the return conduit I5, or between cooling chamber 33 and feed pipe I0.

Fig. 2 discloses cooling and separating apparatus of the open type wherein fresh air is continuously drawn in, cooled, and employed to lower the temperature of the material which is intermixed therewith, after which it is expelled into the atmosphere instead of being re-cooled for subsequent use. In common with the apparatus disclosed in Fig, 1, this embodiment of the invention includes a feed pipe I0 leading into a conduit I3 which in turn leads to a blower I I and then through conduit I4 to separator I2. Air

from which the materialhas been separated is discharged into the atmosphere outlet or vent I50. Air communicating chamber I32 of the water spray type is provided with an air inlet 46, a battery of spray nozzles 4'I, as best shown in Fig. 3, and water eliminators 48. Nozzles 41 are supplied with cold water by pump 60, the fluid delivery of said pump being responsive by means of control unit I24 to temperature changes in the discharged air flowing through discharge pipe I50. The feed delivery mechanism is also responsive to discharge air temperature changes as heretofore described with reference to Fig. 1 but for the purpose of simplification, the mechanism is not shown. If the cold water supply is sufiiciently cold, the water therefrom is pumped directly to the wash nozzles 41 after which it is discharged through an overflow pipe and not recirculated; but where the water supply is not cold enough the water may be refrigerated and re-circulated by pump 60 the same as by pump 44 and washer 33 in Fig. 1.

Fig. 4 discloses apparatus adapted to operate ,on the closed cycle principle without employment of an air washer. The structure is identical with that shown in Fig. l and heretofore described with the exception that refrigerating unit I33 replaces both units 32 and 33 of Fig. 1. Means for controlling feed delivery and blower speed in response to air stream temperature changes will preferably be employed, but have been omitted, as in Fig.2, for the purpose of simplification. It is understood that each of the control means described heretofore are equally applicable to this structure. I

I have found that When ordinary pipe, circular in cross section, is employed in the cooling unit I33 that substantial deposits of dust will tend to accumulate on the back side, calling the side first contacted by the air stream the front side. This accumulation is due to the presence of a dead air space along the back of thepipe. These deposits have an insulating effect'which results in a substantial retardation of heat transfer from the surrounding air to that portion of the pipe.

air stream in p ssi g, contacts all of its outer surfiacano deposits willresult, hence, the-pipes -wil1 be keptclean. Further, I a greater-amount of heat -transfer will :take place-between the air streamand the fluid flowing through the pipe ,due'toan increased area-of pipe surface'being .contactedbyrthe air: stream. Therefore, I prefer to providepipes of streamlined shape as shown in Fig.6, the cross sectional shape being such as 'to closely simulate the natural path of air cur-- zrents travelling over the pipe. Dead airspaces are eliminated by the use of this steramlined pipe =and-eddy currents set up by the air stream as it .passes-thereover:arereduced to a minimum. I have .found that theair stream -is suflicient to keep .the :pipes of closed circuit, Fig. 2, ina dry condition-hence-thedust which might stubbornly stick to their surfacesif wet-has no tendency to cling thereto.

'In this closed circuit the material is dry and with allatmospheric air excluded in cycle there in Fig.4, it is possible to chill-product toalower degree if desired than with the coil with water spray or with the fluid treated to-prevent freezing in cooling unit as in Fig. 1.

. :Figs. '7 and-8 disclose alternate constructions :of my streamlined pipes wherein a conventional pipe of circular cross section is provided with a shroud or jacket-52 which is substantially V- -shaped-in cross section and hasleg portions weld- 'ed:or otherwise secured=to the walls of the pipe.

Jacket 52 is provided with an axially extending inner fin 53 intermediate the jacket walls- Fin 53 has its-outer edge in contact with the outer surface of pipe 5| to provide additional'heat flow between the pipe and the jacket. As shown in Fig. Laseriesof radially extending flns 54 may be provided to promote heat flow, in which case axially extending fl-ns -53 may be eliminated if desired, The pipes may be arranged in staggered fashion withinchamber I33 as disclosed by the cutaway portion in Fig. 4, or they maybe arranged'in'amanner as disclosed in Fig. 5.

111 18, :of course, important that the apparatus through which the air stream flows is sufliciently insulated to substantially prohibit heat transfer from the relatively warm outside atmosphere into thecool air stream. This may be accomplished either by individuallyinsulating the various units and conduits comprising the device, or by enclosing the entire device within an insulated compartment.

1. A method of regulating the refrigeration of finely divided material to a predetermined uniform temperature, consisting in establishing a flow of fluid refrigerant in a stream delivering the said material; into the flowing stream of fluid refrigerant to be refrigerated in direct contact with the stream and regulating the rate of such d'eliveryin accordance with the temperature of at least a portionof the stream at a point beyond the delivery of such material thereto. a

. 2. A method of lowering the temperature of finely divided material, consisting in delivering the material into a stream of fluid refrigerant and regulating the velocity of the stream in accordance with the temperature of the stream at a point beyond the delivery of such material thereto. a

3. A method of preserving a finely divided organic material, consisting in commingling the material with! a streamofr pro-cooled rfluid refrigerant and maintaining therstream in continuous circulation from the .-.-point of -.cor n mingling to-a. point ofwseparatiomand regulating: both the rate of feed of-materi-al at the point of commingling and the speed of refrigerant with reference to the temperature'ofthestream adjacent the point of separation.-

4. A method of cooling comm'inuted particles of stock food, compris ing metering the particles thereof into a'pre-coole'd gaseous stream to be entrained thereby, transmitting the stream and entrained particles through a conduit to effect aheatflow from the particlesto the gas, separating the particles from the stream -and storing theparticles in packed form-tosubstantially exclude atmosphericheatduring storage.

A method of cooling comminuted particles -of;stock food, comprising delivering the heavier andlighter particles thereof into a pro-cooled gaseous stream to-be entrained thereby, pneumatically conveying the entrained particles in said stream to effect a heat flow from theparticles to the gas, expandingthe cross-sectional area of the gaseous stream to retard therate of flow thereof with a resu ltan t separation. of the largerhparticles from the stream, mechanically conveying the heavier particles to-the upperportion of the stream and redelivering them across the stream to prolong their exposure to the stream as compared with the period for which the lighter particles areexposed in their continuedpneumatic movement and therebyto -reduce their temperature to substantiallyth'at-of the light particles, and then separating all the particlesfrom the stream.

.6.--A method of cooling comminuted particles of stock food as set forth in claim 5, including metering the particles into the cooled stream at a rate responsive to temperature changes of the gaseous stream duetoabsorption of heat "units therefrom, and controlling the rate of material introduction into. the stream in response to temperature changes in the fluid discharged.

9. In a. device of the character described the' combination with regulating means [for feeding comminuted material into a preecooled gaseous stream in com-mingled relation therewith, of means disposed in the stream at apoint at which the cooling'function of the stream has been performed, said means, responsive to temperature changes in the gas resulting from heat transfer from the material to theses, and means .operatively connecting, the temperature responsive means to the regulating means to increase the rate of operation of the. regulating means in I proportion to the temperature response.

lO..-A process of cooling comminutedorganic material preparatory to storage thereof, comprising metering the material into a stream of dry gaseous refrigerant to lower the temperature thereof, separating the cooled material from the gas, re-cooling the gas and simultaneously extracting moisture therefrom by passing .the gas over refrigerated surfaces and re-circulating the re-cooled gas to repeat the cycle. a

11. Apparatus of the character described including acooling chamber provided with refriga erating mechanism and adapted to receive. atmospheric air and, remove heat therefrom, a centrifugal separator spaced from said chamber and connected thereto by a closed fluid conduit, means for circulating air from the cooling chamber to the separator, and means for metering comminuted stock food into the conduit at a point spaced from the separator to be entrained by the air strea m and be delivered to the separator to be separated from said stream, whereby heat is extracted from the material during its entrainment within the air stream, means for regulating the air circulating means and means for controlling theoperation of the air regulating means in accordance with temperature in the air stream near the separator.

'12. A device of the character described having in closed circuit relation, a cooling chamber, a blower, a separator, a dry gas within the circuit and adapted to flow therethrough, means variable as to speed for delivering finely divided feed into the gas between the air cooler and the. separator, and a heat responsive device intermediate the separator and the cooling chamber and operatively connectedwith the delivery means, whereby the rate of delivery into the gas is responsive to temperature changes of the 'gasb'et'ween the separator and the cooling chamber. v

13. .A ,devicelof the character described having in closed circuit relation, a cooling chamber, a bloweLfa-separatona dry gas within the circuit and adapted to .flow therethrough, means for expandingthe gas to retard the flow thereof between the heat delivery means and the separator, and a heat responsive deviceintermediate the separator and the cooling chamber and operatively connected with the delivery means, whereby the rate of delivery into the gas is responsive'to temperatur changes of the gas between the separator and the cooling chamber.

14. A device of thecharacter described having in. closed circuit relation, a cooling'chamber, a blower, a separator, a dry gas within the circuit and adapted to flo'wfrom the cooling chamber to the separator and to be discharged therefrom, means variable as to speed for delivering finely divided feed into the gas between the aircooler and the separator, and a rotatable drum of relae tlvely large cross-sectional area disposed within the circuit between the feed delivery means and the separator and lifting means attached to the inner walls thereof whereby to convey therelatively heavy particles from the bottom of the drum to the top portion thereof and'redeliver them into the gaseous stream, whereby the heavy particles fall to the bottom of the drum as the gas expands and are subjected to a longer period of cooling than are the light particles to cool them to approximately the same temperature.

15. A device of the character described having in closed circuit relation, a cooling chamber, a blower, a separator, and a dry gas within the circuit and adapted to flow therethrough, means for re-cooling the gas, said means comprising refrigerating coils so proportioned as to area and temperature as to chill the refrigerating gas withoutreduclng it to the dew point, whereby the coils ar maintained free from condensation, and dust entrained in the gas does not cling thereto.

16. A device as set forth in claim 15 provided with streamlined refrigerating coilswhereby dur ing operation of the device dust particles will not cling to any portion of the coil surface and eddy currents will be reduced in the passage of gas thereover.

17. A substantially continuous method of regu-- lating the refrigeration of finely divided material to a predetermined uniform" temperature, said method consisting in establishing a flow of liquid refrigerant in a defined stream, delivering the said material into the flowing stream of fluid refrigerant to be refrigerated in direct contact with the refrigerant and to receive motion from said stream, and regulating the rate of material delivery to said stream in accordance with the temperature of at least a portion of the stream which has absorbed heat from said material.

18. A method of lowering the temperature of a.

given material, consisting in exposing the material to the direct action ofa stream of fluid refrigrant and regulating the period of exposure of the material to the stream in accordance with the temperature of a portion of the stream' which has acted upon saidmaterial. I 19. A substantially continuous refrigeration method, which includes theestablishment of a flow of liquid refrigerant in a. stream having substantially well defined boundaries, dividing the material to be refrigerated into parts sufficiently small to permit of continuous handling, delivering such material substantially continuously. into the said stream of fluid refrigerant, within theboundaries thereof, moving said material and agitating it while said material is fully and directly exposed to the fluid refrigerant of said stream, removing the material from the stream at a point remote" from the point of delivery of the material to the stream, and regulating theperiod of pressure of the material to the stream between said points in accordance with with the temperature of a portion of the stream which has been exposed to said material.

21. A method of lowering the temperature of small particles of material, such method consisting in establishing a stream of fluid refrigerant, delivering to such stream the small particles of material to be refrigerated, and using the energy of the stream of refrigerant to advance the material while the material gives up its heat to the refrigerant.

22. A method of refrigerating finely divided material, which method consists in propelling a gaseous refrigerant in a stream, introducing into such stream the finely divided material to be refrigerated, pneumatically propelling such material in said stream while abstracting heat therefrom by direct contact of the material with the stream of refrigerant,'whereby it is pneumatically conveyed, and separating the material and said stream.

ticles, which compris fil ed; r aqua god t sc n-t mg 6 1 t a -cs. particles of o ube e i crat dithe it E sion of the refrigeratedgas' insuch"stream eiii g conducted at such a rate'with reference t t f characteristics of the particles of food as to' have sufficient energy toadvance such particles of foodalong the path r'mp ement stream while receiving heat from su bydirect contact th gz rei witl1'.

fmet f q 'inelfaod m a a t fi ho m sin ;t m i l n. fa ei a streamythe reirige'ration lithe gals 'ot saidl stream, the introduction of particles of j food into the previously refrigerated gas" of said streamethe propulsion ofgas'infthe stream bei 7 do I c d W i ht t e wd? P rt1: J l '1? convey suchparticles with 'thestre V v gas of the stream isfabstractingheajt'frqm sue particles, the separation of the gas -stre'a the particles; and the storage or theco' particles infclosely packed masses.

25; A method of cooling sma1l particleso ffood, which method comprises j refrigerating ag-as, the introduction of the food particles'intc'refrigerat ed gas, the circulation-oi 'the 'reirig'eratewgas"in a. stream at a rate such as to entrain the" fiiod particles for pneumatic convection thereoffdurf ing the chilling offsu ch'particlesjby thelg s in fluid current,' of' means for "propelling fluid iii' a current throughsaid path-defining mans, are}; frigerator to which the fluid' of said currentds exposed whereby such fluid ischilled and means forintroducinginto the fluid-"oi s idii c'ur rentl' particles of material sufiic'ientl'y" light to" be advanced by said current'while cool'ed by direct contact with said fluid.

27;In' a device or the character described; the;

combination-With a conduit for gas, of an air coolerar'ra'nged to deliver cooled gas to said conduit; means for establishing a current of cooled gas'through said conduit at a speed suflic'ient-to entrain particles of material delivered into the gas to be propelled and cooled thereby; a 'feeder adapted and positioned to deliver into the cur-' rent of gas in said conduit material in sufficiently light form to be advancedby theg'as current in" said conduit while cooled by direct contact with the gas of 'said-current,and means Withwhi'ch said conduit communicates 'for separating the cooled material from the gas. a

28. The'apparatus setforth in claim 2'? in which the means for'propelling gas through the conduit operates at such a rate with respect to the characteristics of the materialtq be'cooled that the current of gas is adapted toentrain such material for its pneumatic propulsion in 'thejconi dui t while beingcooled, said conduit ems-Emm ing means together'providing for suffi i'erit length of convection trave of the material with; th gas to effect the cooling of such matriali 29. Apneumatic refrigerating and conveying system comprising an aircool'er; a gas DQmFQ a separator, and a blower; in appropriate slegi es order, said blower comprising means for propel- I said,

thereby, re -circulating trig ling through the conduit and separator-gaschilled m semi cooler at1sucli a rate-as to" "impart"- its energy' to 'finely divid'ed parti'clesior thepneu matic propulsion mereortnmiign said "system w'hilecooling such-particles," together witlra feeder in operative-connection with saidsystem for delivering particle's"'ot'm'aterialinto'the path of gas: in saidsystem in said-condui-t'inadvance of said blow er, the path "of trai elfins'al'clfsystem between said feeder and the point of separation of the" gas from said -materia1 m said separa tor beingsulflicient to neet'rqiureaeemm of the m aterialfin direct contact with the gaseous; currentwhereby it is conveye'd 'and cooled.

'30. A method of low'erinjg the temperature of small particles of material, such methodcon sist ing in establishing a stream of fluidrefiige'rantl deliveringlto such stream the small particles'of; ma erial j r tr e' a r amen-Sing, the n of the stream of reirigerant to advance therma terlal while thematerialgives upits heat tothe refrigerant; separating the material frorn the stream, recirculating the s'treamin a closed refrigerant, circuit, and; removing heat "from there ri jerant t w. n e. ou se of .i edi l t-t cuitm vement. I i A me hil v f, l ing fi emneratur f smallparticles'of materialpsueh'fmet ing infestab ration .from the strea i erantcircuit jandm em rejfrigerant i th cburse ot its recircul t ria 'gj hq fieiroiii,

e d by said stream to proilide for; the pneumatic cqnvection of 'said material e'n trained with the stream a dfforjthe centrifugal}

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