Патент USA US2137902код для вставки
Nov. 422, 1938. ¢_ T_ WALTER 2,137,902 QUICK FREEZ ING PROCES S Filed NOV. 2l, 1936 ' 4 2 Sheets-Shee‘b 1 ........................ .. 'I | 22 «fhä „ze IIi 4,ffl I a A l vg» Í „ze 12 .......... n 17 Y ö’ 1 19| « ........ .. . j.. ATTEST’ ßlacmßgw. B . Z2 ATTORNEY Nov. 22, 1938. Q_ T_ WALTER . 2,137,902 QUICK FREEZING PROCESS Filed NOV. 2l, 1936 2 Sheets-Sheet 2 ATTORNEY \ 'Patented Nov. 22, 1938 2,137,902 UNITED STATES PATENTl 2,137,902 @UNIE FREEZINGÍ PROCESS Charles 'i'. Waiter, Chicago, lill., assigner to in» dustrial Patents Corporation, Chicago, mi., a corporation of Delaware Application 'November El, i936, Ferial lilo. Multi’ it matroos. This invention relates to a quick ‘freezing process for foods and to apparatus for carrying out the process. One of the objects of the invention is to provide 5 an improved quick freezing process. Another object of the invention is to provide apparatus for carrying out an improved quick freezing process. Other objects will be apparent from the de scription and claims which follow. As is well known, quick freezing involves ad« vantages over slow freezing in that in quick freezing the ice crystals formed in the foods are small and do not rupture the cell walls, avoiding 15 an excessive moisture loss by cellular leakage upon defrosting. The present invention is particularly adapted for quick freezing poultry. Embodiments of apparatus involved in the' Valve i2 is employed for closing the retort ofi from the compressor. Pump iii is provided to re» turn to the receiver any liquid refrigerant re» maining in retort i after completion of 'the freezing operation prior to opening the retort for it removal of the product. Liquid refrigerant in the retort returns to receiver it through line 2t provided with valve 2| and line il? provided with valve 23. Gauge 24 is provided for visual ¿ob servation of the level of liquid refrigerant in li) retort i. The apparatus shown in Figure l may be oper ated in the following manner: Assuming valves I2 and I8 are closed and that receiver I6 is filled with liquid refrigerant under l5 suitable pressure and temperature conditions, retort I is open at head 2, the desired quantity of product is loaded into the retort and cover 2 tightly closed. Valve II is opened slightly to al 20 present invention are shown in the drawings. low air retained in the retort to escape. Valve I8 20 is next opened and a suitable quantity of refrig of one form of apparatus involved in the present I erant permitted to flow into retort I through pipe I1. A sufiicient quantity of refrigerant is admit invention. ted to retort I to completely cover all product to Figure 2 is a side view, partly in section, of an 25 other form of apparatus Vwhich may be employed be refrigerated, the level being observed in gauge 25 24. When it appears that substantially all air in carrying out the process of the present inven Figure 1 is a schematic view, partly in section, tion. ' ' Referring now more particularly to Figure 1: Retort I is provided with a removable head 2 at 30 one end. Head 2 may be held tightly in position by any suitable means as bolts 3 and wing nuts 4, and is removed to charge the retort with product to be frozen. Product 5 is placed in retort I on rack 6. It will be noted that retort I is provided 85 with vapor chamber 1 to avoid return of slugs of liquid through pipe 8 to compressor 9. The present invention is carried out with a within the retort I has b'een discharged through valve I I, this valve is closed. Pressure is now built up in retort I. The pressure will depend upon the nature of the refrigerant and the temperature of 80 the product and retort. Valve I8 is closed after a suitable quantity of refrigerant has been admit ted to the retort. Compressor 9 is then started and valve I2 opened, starting the 'pumping down process. As soon as compressor 9 starts to re- 35 move gas from retort I, some of the liquid refrigerant in retort I evaporates, reducing the suitable liquid refrigerant, as for example liquid - temperature of the mass of liquid refrigerant and the surrounding materials. As the vapor pressure in retort I is lowered, the temperature 40 II. Pipe 8 is provided with valve I2 and returns of the refrigerant is lowered. With such refrig erants as liquid carbon dioxide, very low tem gaseous refrigerant to compressor 9 from cham peratures may be obtained, and consequent rapid ber 'l of retort I. Compressor 9 delivers the com pressed refrigerant in gaseous form through line chilling of the product in trays 6. 'I'he shell of the retort is heavily insulated 45 I3 to condenser I4 which may be of any suitable type and is designed to discharge the liquefied- against the transfer of atmospheric heat into the refrigerant through pipe I5 into receiver I6. Re system as by insulation 25. Similarly the receiver ceiver I6 is preferably of large capacity and is heavily insulated as by insulation 26. ‘As the freezing of the product proceeds, if more should contain enough of the liquefied refrig refrigerant is desired to maintain complete sub- 50 erant to fill retort I to the desired level. . Liquid refrigerant is delivered from the receiv mersion of the product, the desired quantity may er I6 to retort I through pipe I1 provided with be admitted at will through valve I8. After freezing has proceeded to the desired ex valve I8 which functions as the control valve for shutting off the receiver I6 from the retort l, tent, valves 2I and 23 may be opened and pump I9 placed in operation to pump the remaining 55 ~when the retort is to be opened. carbon dioxide. Before the system is started, air 40 Ais removed through pipe I0 provided with valve 45 ' 50 ' 55 2 liquid refrigerant from retort I into receiver I6. After all of the refrigerant in retort I has thus been returned to receiver I6,` valves 2l and 28 may be closed. Compressor 9 should continue to operate until the'pressure in retort i has been reduced to atmospheric pressure or less. Com pressor 9 may then be stopped and the retort I tinues to operate, the temperature of the liquid refrigerant continues to lower, concurrently low ering the pressure within space 28. The com.-` pressed gas passed into the condenser I4 is lique fled and returned to receiver I6. After'a period of time, any desired temperature for the liquid refrigerant may be obtained within the limits of 'opened with safety to permit removal of the the physical characteristics of the refrigerant. product. about the product will be rapidly and completely For example, if the liquid refrigerant is carbon dioxide and it is desired to operate ata tempera 10 evaporated from the product during subsequent pounds per square inch will be maintained in handling. receiver I6. After the desired temperature oi the refrigerant has been reached, it will be main tained while the compressor is operated at the 15 suction pressure corresponding to that tempera ture. Retort l is now filled with a quantity of the product to be refrigerated, head 2 tightened in place, and air pump 29 started for the purpose 20 of extracting air from chamber I and to avoid the introduction of substantial quantities of un liqueflable gases into the system. If desired, a simple blow-off valve may be provided as a sub stitute for air pump 29 permitting the valves to 25 , Any liquid refrigerant which may remain inv or . In the refrigeration of foods, it is essential that 15 the refrigerant be one which is not absorbed and must be one which is relatively inexpensive, non toxic, convenient to handle, and which has physi cal and thermal characteristics making possible extremely low temperatures and rapid rates lofl heat exchange. Liquid carbon dioxide is such a refrigerant. ` ' Referring now more particularly to Figure 2: Retort I is provided with head 2 which may be securely fastened to retort I by means of bolts 3 and wing nuts 4. Product 5 may be placed upon racks 2l. It is understood, of course, that retort i must be sufficiently strong to 'withstand the ordinary working pressures to be imposed upon it. Retort I is covered with insulation 25 and receiver I5 is covered with insulation 26. Re ceiver i6 functions as a liquid receiver and as an evaporator and is connected to retort I by pipe Il provided with valve i8. Chamber I 6 is adapted to hold a quantity of liquid refrigerant to any suitable level, the space 2t above the lique fied refrigerant being occupied by the refrigerant in its gaseous state. A suitable compressor machine 9 is included in the`systern to deliver the hot compressed gas to the condenser ld through pipe i3 where it is liqueñed and returned to receiver iii through pipe iii. Airfpump 2@ is provided to exhaust chamber i of air at the start of the freezing cycle communicating with retort i through pipe Sti' and pipe i0 provided with valve 3i. Pipe 3i! is provided with valve 32. Air withdrawn by pump 29 is exhausted through pipe 33. The pump 34, suitable for handling liquid refrigerant, is em ture of 0° F., a. pressure of approximately 300 remain open after a small quantity of liquid car bon dioxide is introduced into chamber I. The evaporating carbon dioxide will tend to dispel the air through the blow-off valve, but this method would entail a loss of refrigerant and, conse 30 quently, the pump is preferred. After the chamber i has been well exhausted by the action of air pump 29, valves I8 and 32 are opened, permitting the prechilled liquid re frigerant to enter the retort and completely or partially flood the interior of retort i. Liquid 35 refrigerant comes in contact with the product to be chilled at the minimum temperature of the refrigerant, causing freezing of the product to commence immediately. Contact of the liquid refrigerant with the warm. product results in a 40 heat exchange and the evaporation of some of the liquid refrigerant. The gases thus formed are drawn oiî through pipe line 3S to the com pressor 9, maintaining a minimum temperature of the refrigerant at a constant value. The system assures that the maximum pressure in retort i is that pressure corresponding to the ployed to return quantities of liquid refrigerant ~ minimum temperature of the refrigerant. ' The from retort l to receiver lâ at the end of the carbon dioxide operating from 0° to 50° F. the 50 freezing process. Pump 34 removes -refrigerant maximum pressure in the chamber will be about 50 from retort i through pipe 35 provided with valve 300 pounds. On the other hand, the pressure> 3d, and returns the refrigerant from receiver i5 which may exist in -receiver i6 will be much through pipe 3l communicating with pipe i5. higher than this and will correspond to the vapor Retort i is provided with safety valve 38 to pre pressure of the liquid refrigerant at the highest 55 vent damage to the apparatus in, the event of excessive pressure. Duringthe operation of the system, gas evap orating from the liquid refrigerant in retort i is Withdrawn through pipe 39 communicating with pipe dil at d i. Gaseous refrigerant formed in the receiver I5 may also be withdrawn through pipe dil to compressor 9. Pipe il@ is provided with valve d2 between compressor it and T di. 65 The operation ofthe apparatus will be readily understood by reference to Figure 2. Assuming that the receiver I '6 is nearly full of liquid refrig erant such as liquid carbon dioxide, the liquid being at room temperature, valves iß'and 32 are 70 closed. Valve d2 is opened` and the compressor 9 started. The vapor pressure in space 2S will be reduced and some ef the liquid refrigerant will be evaporated. This evaporation will bring about a reduction in the temperature of the re 75 maining refrigerant. .As the compressor con temperature that may prevail in the receiver, which may be as high as 100° or more F. After the system has operated sufficiently to chill or freeze the product to the desired degree, the freezing operation is stopped by closing valves i8 and 32, and starting pump 34, drawing oil” 60 from the bottom of the retorti the liquid re frigerant remaining therein and returning it through pipe 3l to receiver I6. The refrigerant is not heated before being returned to receiver i6, 65 but is returned at approximately its minimum temperature. After all of the liquid has -been withdrawn from retort I, pump 34 may be stepped and valve 36 closed. Valve 42 may be closed and valve 32 opened. With the compres sor operating, retort I may be pumped down to atmospheric pressure. It is now in condition for opening and removal of the product. The apparatus which has been described re suits in extremely rapid freezing, permitting a 75 3 9,137,902 chicken to be frozen solid in about 15 minutes. means including an air pump having means com This rapid freezing is brought about by the ex~tremely low temperature involved and the inti vmate contact between the freezing medium and the product to be frozen. Due to the efficiency of the apparatus, its capacity is high and the in liquefied refrigerant, a freezing retort, a liquefied refrigerant receiver connected with said retort by vestment relatively low. ` I claim: 1. In a freezing device, a product retort, a pipe 10 from said retort communicating with a compres sor, a condenser connected with said compressor, a liquefied refrigerant receiver connected' with said condenser, a pipe communicating with said receiver and said retort, and a pump for returning 15 liquefied refrigerant from said retort to _said re ceiver as desired. 2. In a freezing device, a product retort, a pipe from said retort communicating with a com pressor, a condenser connected with said com 20 pressor, a liquefied refrigerant receiver con nected with said condenser, a pipe communicat ing with said receiver and said retort, a pump for returning liquefied refrigerant from said retort to said receiver as desired, and an air vent pro 25 vided with a valve for preventing excessive pres sures within the retort. 3. In a freezing device, a product retort, a pipe from said retort communicating .with a compres sor, a condenser connected with said compres 30 sor, a liquefied refrigerant receiver connected with said condenser, a pipe communicating with said receiver and said retort, a pump for return ing liquefied refrigerant from said retort to said receiver as desired, an air vent provided with a 35 valve for preventing excessive pressures within the retort, a valve positioned between said re ceiver and said retort, a pipe connecting said pump and said retort, a valve in said last men tioned pipe, and a pipe connecting said pump and 40 said receiver. 4. In a freezing device, a product retort, a pipe from said retort communicating with a compres sor, a condenser connected with said compressor, a liquefied refrigerant receiver connected with 45 said condenser, a pipe communicating with said receiver and said retort, a pump for returning liquefied refrigerant from said retort to said re ceiver- as desired, an air vent provided with a valve for preventing excessive pressures within the re 50 tort, a valve positioned between said receiver and said retort, a pipe connecting said pump and said retort, a' valve in said last mentioned pipe. a pipe connecting said pump and said receiver, and municating with said retort for exhausting air from said retort. 5. In apparatus for quick freezing food in a a pipe, a valve in said pipe, a pipe leading from said receiver to a compressor, said last-mentioned pipe provided with a valve, a pipe leading from said retort to said compressor. said last men 10 tioned pipe'provided with a valve, a pipe lead ing from said compressor to a condenser, a pipe leading from said condenser to said receiver,apipe leading from said retort to an exhausting air pump, a pipe leading from said retort to a liquidl l5 pump, a valve in said pipe between said retort and said liquid pump, and a pipe leading from said liquid pump to said receiver. 6. In a quick freezing device, a closed retort having openable means for admitting product thereto, a liquefied refrigerant receiver commu nicating >with the retort, means controlling the ñow of liquefied refrigerant from the receiver to the retort, a compressor condenser circuit con necting the retort with the receiver, said com presser condenser circuit being adapted for with drawing gaseous refrigerant from the retort and for delivering liquefied refrigerant to the receiv‘~ er, and means for delivering liquefied refrigerantI 30 from the retort to the receiver. 7. In a quick freezing device, a closed retort having openable means for admitting product thereto, a liquefied refrigerant receiver commu nicating withthe retort,meanscontrolling the flow of liquefied refrigerant from the receiver to the retort, a compressor condenser circuit connecting the retort with the receiver, said compressor con denser circuit being adapted for withdrawing gas eous refrigerant from the retort and for deliver ing liqueñed refrigerant to the receiver, and means including a liquid pump for delivering liquefied refrigerant from the retort to the re ceiver. 8. The method of quick freezing food products which comprises submerging the food in a lique fied refrigerant in a closed system under pres sure, continuously withdrawing gaseous refrig erant, continuously returning liquefied refriger ant at a substantially constant low temperature until completion lof the freezing process and thereafter withdrawing all of the liquefied re frigerant from the system. . CHARLES T. WALTER.