USRE20848E

USRE20848E - Refrigeration

Info

Publication number: USRE20848E
Authority: US
Publication date: 1938-09-06

Description

Sept. 6, 1938. A. T. LIGHT 20,848

REFRIGERATION I f Original Filed Oct. 25, 1927 4 Sheets-Sheet l ATTORNEY Sept. 6, 1938. A. T. LIGHT Re. 20,848

REFRIGERAT ION Original Filed Oct. 25, 1927 4 Sheets-Sheet 2 AT TORNEY -A. T. LIGHT.

REFRIGERATION Sept. 6, 1938.

Oi-iginal Filed Oct. 25, 1927 4 Sheets-Sheet 5 Sept. 6, 1938. A; T. LIGHT Re. 20,848

REFRIGERATION Original Filed 001;. 25, 1927 4 Sheets-Sheet 4 j uz ATTORNEY Reiasued Sept. 6, 1938 UNITED STATES PATENT OFFICE 20,848 REFRIGERATION Original No. 1,866,988, dated July 12, 1932, Serial No. 228,529, October 25, 1927.

Application for reissue July 11, 1934, Serial No. 734,698

30 Claims.

This invention relates to refrigeration, and

particularly to means for putting an evaporator quickly into and out of operation at will. The

invention has particular utility in the freezing of ice cream, and for purpose of illustration will be described as so applied.

The invention aims to provide a means for freezing the ice cream expeditiously by bringing the liquid refrigerant into direct contact with the freezing cylinder, and to cause a rapid change in freezing conditions at the end of the freezing period by immediately removing the liquid refrigerant from contact with the freezing cylinder, thereby facilitating the whipping process.

The device includes a. low pressure receiver into which the liquid refrigerant is delivered from the condenser, suitable mechanism such as a pump for-circulating the refrigerant about the freezing cylinder and draining means for quickly removing the refrigerant from contact with the freezingcylinder when desired, and returning it to the receiver.

While preferred embodiments of the invention are herein disclosed for purposes of illustration, .it should be understood that various changes may be made in the structure without departing from the spirit and scope of the invention as hereinafter set forth and claimed.

. In the drawings Flg. 1 is a front elevation of a freezer constructed according to this invention.

Fig. 2 is a side elevation of the machine of Fig. 1.

Fig. 3 is an enlarged section of mechanism.

Fig. 4 is an elevation driving mechanism.

Fig. 5 is a rear elevation of the driving mechanism.

Fig. 6 is a side elevation of another embodiment of the invention.

Fig. '7 15a sectionaldetail.

Referring to the drawings more particularly, the machine includes a base It], upon which are supported'the various parts of the freezer. The freezingcylinder i I (Fig. 4) is surrounded by the insulated casing l2, and the jacket space I3 lying between the cylinder II and the casing l2 constitutes the evaporator.

In carrying out the objects of the invention any preferred volatile liquid refrigerant is brought into contact with the exterior of the freezing cylinder II during the 'period during which the ice cream is being frozen in the cylinder. After the ice cream has reached a certain part of the partly in section of the consistency it is desirable to prevent any further lowering of the temperature of the ice cream, and then to continue to whip it with the beating elements until it has attained the proper swell or overrun. During this whipping period the temperature should not drop, but should remain practically stationary or should rise slightly. In order to attain this end the invention provides for removing the liquid refrigerant from contact with" the freezing cylinder during the whipping period.

One arrangement for handling the liquid refrigerant is illustrated in Figs. 1 and 2. This mechanism includes a tank or low pressure receiver it carried by the base Ill below the casing i2. A high pressure liquid refrigerant supply line [5 carries the liquid refrigerant from any suitable compressor and condenser, not shown, through strainer I6 and float valve I] to the receiver It. The float valve is arranged to shut oif the incoming supply whenever the liquid in receiver I4 reaches a certain level. A supply line l8 leads from the bottom of the receiver H through a control valve Hi to the lower part of the evaporator I3. A pump 20, operated by a motor 2|, is interposed in the supply line [8 for pumping the liquid through line l8 and control valve l9 to the evaporator. A return line 22 runs from the top of the evaporator l3 back to the receiver It, thus completing a closed circuit which includes the evaporator and the-receiver.

The control valve I 9 is shown in detail in Fig. 3 and includes a casing provided with a chamber 23 having a conical seat 24 at its upper end and a port 25 leading through one side. The moving element comprises a barrel member 26 which carries near one end a conical valve head 21 which fits into the seat 24, and at its other end a disc 28 which fits closely in the chamber 23. A passage 29 leads through the center of the barrel 26. 40 A drain connection 30 leads from port 25 to the return line 22. The supply line I8 leads into the bottom of the chamber 23 through the cover plate 3|.

The stirring elements within the freezing cylinder comprise a scraper 32 which moves in one direction next to the inner wall of cylinder II,. and an inner beater 33 which moves in the opposite direction. These elements are operated by mechanism now to be described.

The scraper 32 carries at its rear end a hollow shaft 34 which projects through oneend of cylinder H and has a. sprocket 35 keyed thereto. A shaft 36, connected with thebeater, extends through the shaft 34 and has a sprocket 31 keyed thereon, the outer end of shaft 33 being supported in a bearing 38 mounted on base I0. A motor 39, in the lower part of base III, has its shaft '40 provided with drive sprockets 4| and 42 alined with

sprockets

35 and 31 respectively. A sprocket chain 43 extends around the sprockets 4| and 35 and is tightened by the idler 44. A second sprocket chain 45 has its upper end passed around the sprocket 31 and its lower end passed around an idler 46 located below the sprocket 42, one side of chain 45 being partly wrapped around the driving sprocket 42 as will be clear from Fig. 5. Because of this arrangement, when the shaft 40 rotates in a clockwise direction, the sprocket 35 will rotate in the same direction, while the sprocket 31 will rotate in a counter clockwise direction, and the beater and scraper will therefore be rotated in opposite directions. This mechanism provides a simple and direct drive and eliminates the large friction losses in-..

cident to the use of bevel gears, and other types of gear devices. A casing '41 encloses the sprockets I5 and 21. l

The machine operates in the following, manner: 1

After the batch of cream has been placed in the cylinder II the motor 19 is started, thereby putting the stirring elements into operation. At the same time the motor 2| which drives pump is set into operation. This pump draws the liquid refrigerant from the bottom of the receiver l4 and discharges it into the chamber 23. The pressure created below the disc 28 pushes the member 26 to its upper position illustrated in Fig. 3, shutting of! passage through pipe but permitting the liquid to flow through passage 29 and thence via line ID to the evaporator ll. When the evaporator becomes fllled,;liquid and vapor will pass through overflow line 22 back to receiver l4, and the pump 20 will keepcirculating the refrigerant through the evaporator in direct contact with the entire outer surface of cylinder l I, thereby bringing about a very rapid and uniform cooling of the batch in the derii.

A gas and liquid separator 48 is in communication with the upper part of receiver l4, and the suction line 49 of the compressor (not shown) leads from the separator to carry 91! the evaporated refrigerant;

When the batch has been frozen to the desired consistency and it is desired to whip the frozen cream, the motor 2| is stopped. This action steps the upward pressure against member 26 and permits it to fall to the bottom of chamber 23, in which position it allows the refrigerant to drain from the evaporator l2 back to receiver l4 by way of the return line 30. In this way the chamber I3 is quickly drained of liquid refrigerant, and no further lowering of the temperature of the charge can then take place. Meanwhile the motor 39 continues to run and the whippers beat up the frozen cream for a period long enough to give the desired overrun.

The tank l4 acts as a low pressure container in .which the liquid refrigerant is kept under practically no pressure, and since it always contains a level of refrigerant, the machine is always ready to start freezing a fresh batch of cream as soon as it is placed in the cylinder H.

In this manner the liquid refrigerant is used over and over by being circulated between the low pressure container i4 and the refrigeration chamber l3, and only such refrigerant as va- 'p0rizes is carried oil to the compressor. The

cylinfloat valve insures a certain level of liquid refrigerant in the container at all times, but there is always enough free space in the container l4 to permit all of 'the liquid in the refrigeration chamber ii to flow back into the container.

It will be observed that the arrangement above described functions to maintain the evaporator flooded when the pump is in operation and to drain it rapidly when the pump stops.

It will be evident that any suitable arrangement could be used to circulate the refrigerant between the low pressure receiver and the evaporator, the essential requirements for ice cream freezing being that the liquid. be brought into direct contact with the freeflng cylinder during the freezing period and be quickly withdrawn at the end of said period.

Another arrangement for carrying out the process is shown in Fig. 6. In this case'the liquid refrigerant is pumped from the low pressure receiver l4 through line 48' to the header 49' located in the evaporator above the cylinder II. The header is arranged-to spray the liquid over the sides of the cylinder II for its entire length. The

liquid is permitted to collect in the refrigerant chamber until it reaches the height of the overflow pipe 5|) which conducts it back to the low pressure receiver. A drain line 5|, controlled by a manually operable-valve 52, leads from the bottom of the evaporator to the low pressure receiver I4. During the freezing period the valve 52 is closed but when it is desired to begin whipping, the pump is stopped and valve 52 is opened, thereby quickly draining the liquid from the evaporator.

In the modified construction above described the evaporator is partially flooded. The location of the overflow pipe 50 determines the depth to which it is flooded, and this may be arranged to suit particular conditions.

An important feature of theinvention is the ability to withdraw the volatile liquid refrigerant from the evaporator quickly and certainly. Another important point is that the evaporator is flooded.- Because of the simplicity of the structure the use of a circulating pump and gravity return flow to accomplish the result just stated is preferred. The use of the by-passing return flow valve which allows the backward flowfrom the evaporator to occur around the pump, is important, not only because it allows displacement types of pump to be used, but also because it gives a relatively rapid return flow. However, there are various ways in which the desired result can be' secured, and except as specified in the claims, no necessary limitation to the particular structure here illustrated is implied.

While the invention has its primary utility in the ice cream field, it is available for use in any fleld where a rapid suspension and a resumption of the evaporator action is desirable.

In certain of the-claims the word cylinder is used to describe the chamber in which the batch tobe frozen is contained during the freezing operation. This is used in the sense in which it is used in the ice cream industry without any implication of limitation to a true or approximately cylindrical form of the chamber.

I claim:

1. An ice cream machine comprising a freezing cylinder, a refrigeration chamber associated with the cylinder, means for supplying liquid refrigerant to the refrigeration chamber in direct contact with the cylinder during the freezing period, and means comprising a portion of said first named means for discharging the liquid refrigerant from the refrigeratidn chamber to expedite the whipping operation.

2. An ice cream machine comprising a freezing cylinder, a refrigeration chamber associated with the cylinder, a low pressure container, means for supplying liquid refrigerant to the low pressure container, means for removing liquid refrigerant from the low pressure container and supplying it to the refrigeration chamber in direct contact with the cylinder during the freezing period, and means comprising a portion of said first named means for discharging the liquid refrigerant from the refrigeration chamber (and returning it to the low pressure container) to expedite the whipping operation.

3. An ice cream machine comprising a freezing cylinder, a refrigeration chambenassociated' with the cylinder, a low pressure container, a feed line adapted to carry liquid refrigerant to the low pressure container, an exhaust line adapted to carry vaporized refrigerant away from the low pressure container, means for removing liquid refrigerant from the low pressure container and supplying it to the refrigeration chamber in direct contact with the cylinder during the freezing period, and means comprising a portion of said first named means for discharging the liquid refrigerant from the refrigeration chamber (and returning it to the low pressure container) to expedite the whipping operation.

4. An ice cream machine comprising a freezing cylinder, a refrigeration chamber associated with the cylinder, a low pressure container, a feed line adapted to carry liquid refrigerant to the low pressure container, a float valve in the feed line, an exhaust line adapted to carry vaporized refrigerant from the low pressure container, means for removing liquid refrigerant from the low pressure container and supplying it to the refrigeration chamber in direct contact with the cylinder during the freezing period, and means comprising a portion of said first named means for discharging the liquid refrigerant from the refrigeration chamber (and returning it to the low pressure container) to expedite the whipping operation.

5. An ice cream machine comprising a freezing cylinder, a refrigeration chamber associated with the cylinder, a low pressure container adapted to receive liquid refrigerant, a feed line adapted to carry liquid refrigerant from the low pres sure container to the refrigeration chamber, a pump in the feed line, and a line comprising a portion of said feed line for returning the liquid refrigerant from said refrigeration chamber to i the low pressure container.

6. An ice cream machine comprising a freezing cylinder, a refrigeration chamber associated with the cylinder, a low pressure container, a feed line adapted to carry liquid refrigerant to the low pressure container, a float valve in the feed line, an exhaust line adapted to carry vaporized refrigerant from the low pressure container, a pump line adapted to carry liquid re frigerant from the low pressure container to the refrigeration chamber, a pump in the pump line, and a return line comprising a portion of said pump line for carrying the liquid refrigerant back to the low pressure container.

7. An ice cream machine comprising a freezing cylinder, a refrigeration chamber associated with the cylinder, a low pressure container adapted to receive liquid refrigerant, a feed line adapted to carry liquid refrigerant from the low pres sure container to the bottom ofthe refrigeration chamber, a return line for the refrigerant, a pressure operated valve controlling a passage to the return line, a pump in the feed line between the valve and the low pressure container, and an overflow line extending from the top of the re frigeration chamber to the low pressure container.

8. The combination of an ice cream freezer having an evaporator directly associated therewith; means for supplying volatile liquid refrigerant to the evaporator; and means including a portion of the first named means for discharging liquid refrigerant from the evaporator.

9. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a low pressure receiver for volatile'liquid-refrigerant substantially devoid of heat exchanging relation with said freezer; means affording a closed circuit'for refrigerant from the receiver upward through said evaporator and back to the receiver; and means operable at will for discharging liquid refrigerant from the evaporator to the receiver.

10. The combination of an ice cream freezer having an evaporator in heat exchanging relationtherewith; a low pressure receiver for volatile liquid refrigerant substantially devoid of heat exchanging relation with said freezer; means affording a closed circuit for refrigerant from the receiver. upward through said evaporator and back to the receiver;power actuated means for circulating liquid refrigerantthrough said circuit in the direction stated; and means operable at will for terminating such circulation and discharging the liquid refrigerant from the evaporator to the receiver.

11. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a low pressure receiver for volatile liquid refrigerant substantially devoid of heat exchangingrelation with said freezer; means affording a closed circuit for refrigerant from the receiver upward through said evaporator and backto the receiver; and means operable at will for discharging liquid refrigerant from the evaporator to the receiver through a portion of said circuit.

12. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a low pressure receiver for volatile liquid refrigerant substantially devoid of heat exchanging relation with said freezer; means affording a closed circuit for refrigerant from the receiver upward through said evaporator and back to the receiver; power actuated means for circulating liquid refrigerant through said circui-t in the direction stated; and means operable at will for terminating such circulation and discharging the liquid refrigerant from the evaporator to the receiver through a portion of said circuit.

13. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a low pressure receiver for volatile liquid refrigerant substantially devoid of heat exchanging relation with said freezer; means affording a closed circuit for refrigerant from the receiver upward through said evaporator and back to the receiver; a suction connection leading from.the receiver; a supply line for liquid refrigerant leading to said receiver; means responsive to the quantityof liquid in the receiver for controlling flow through said supply line; and means operable at will for discharging liquid refrigerant from said evaporator to said receiver.

14. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a low pressure receiver for volatile liquid refrigerant substantially devoid of heat exchanging relation with said freezer; means affording a closed circuit for refrigerant from the receiver upward through said evaporator and back to the receiver; power actuated means for circulating liquid refrigerant through said circuit in the direction stated; a suction connection leading from the receiver; a supply line for liquid refrigerant-leading to said receiver; means responsive to the quantity'of liquid in the receiver for controlling flow through said supply line; and means operable at will for terminating such circulation and discharging the liquid refrigerant from said evaporator to said receiver.

15. The combination of an ice cream freezer having an evaporator in heat exchanging relaopen when the pump is at rest.

16. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a receiver for volatile refrigerant, substantially devoid of heat exchanging relation with said freezer and located at a lower level than the evaporator; means affording a closed circuit through said receiver -and'evaporator; means operable to cause circulation of refrigerant in said circuit; a drain connection from said evaporator to said receiver; a normally open valve controlling said connection; and means actuated by flow in said circuit and operatively connected with said valve'to close the same when such flow occurs.

1']. The combination of an evaporator; a receiver for volatile liquid refrigerant, located at a lower level than the evaporator and substantially out of heat exchanging relation with the space refrigerated by said evaporator; a pump serving to draw liquid refrigerant from said receiver and deliver it to said evaporator; an overflow connection leading from a point above the bottom of said evaporator to said receiver; and means operative when the pump is inactive for drain ng said evaporator to said receiver.

18. The combination of an evaporator; a receiver for volatile liquid refrigerant, located at a lower level than the evaporator and substantially out of heat exchanging relation with the space refrigerated by said evaporator; a pump serving to draw liquid refrigerant from said receiver and deliver it to said evaporator; an overflow connection leading from the top of said evaporator to said receiver; and means operative when the pump is inactive for draining said evaporator to said receiver.

19. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a low pressure receiver for volatile liquid refrigerant substantially devoid of heat exchanging relation with said freezer; a suction connection in communication with said evaporator; a liquid connection between said evaporator and receiver; and means operable at will to supply liquid refrigerant in quantity from said receiver to said evaporator to sustain active re-' frigeration in the evaporator, and to suspend said supply and return unevaporated liquid refrigerant to said receiver to arrest such active refrigeration in the evaporator.

20. The combinationof an evaporator; a receiver for volatile liquid refrigerant substantially devoid of heat exchanging relation with the,

space refrigerated by said evaporator, and located at a lower level than the evaporator; a

pump serving to draw liquid refrigerant from said receiver and to deliver it to said evaporator; an overflow connection leading from a point above the bottom of said evaporator to said receiver; and valve means serving when open to drain said evaporator to said receiver.

21. The combination of an ice cream freezer having an evaporator in heat exchanging relation therewith; a low pressure receiver for volatile liquid refrigerant substantially devoid of heat the evaporator of liquid refrigerant and suspend active refrigeration in the evaporator.

22. In apparatus of the class described, the combination of a container, a casing surrounding said container in spaced relation thereto, a distributor in the space between said casing and container, above the latter, extending substantially from end to end thereof, a reservoir for a liquid refrigerant, means for conveying liquid refrigerant from said reservoir to said distributor,

--and connections for permitting the gravity return of unevaporated refrigerant from said space to the reservoir, and the withdrawal from said space and reservoir of evaporated refrigerant.

23. In apparatus of the class described, the combination of a horizontal, closed container having a material inlet and a valve controlled material outlet, a casing surrounding said container in spaced relation thereto and closed at its opposite ends, a reservoir for a liquid refrlg erant below said casing, a pipe for supplying refrigerant tolsaid reservoir, a valve in said pipe,

means for controlling the operation of said valve, said controlling means including a float in said reservoir and operated by the rise and fall of the liquid level therein, whereby a substantially predetermined supply of refrigerant is maintained in said reservoir, a pipe .in the .space between said casing and container, above the latter and extending from end to end thereof and formed with discharge ports for distributing the refrigerant onto the walls of said container, to permit the refrigerant to flow downwardly over the walls thereof, means for conveying refrigerant from said reservoir to said pipe. and connections for permitting the gravity return of unevaporated refrigerant from said space to the reservoir, and the withdrawal from said space and reservoir of evaporated refrigerant.

24. In apparatus of the class described, the combination of a container, a casing surroundsome ing said container in spaced relation thereto, means in the space between said casing and container, above the latter, for distributing liquid refrigerant onto said container, a reservoir for a liquid refrigerant, means for conveying liquid refrigerant from said reservoir to said distributing means, and connections for permitting the gravity return of unevaporated refrigerant from said space to the reservoir,and the withdrawal from said space and reservoir of evaporated refrigerant.

25. The herein disclosed process of cooling material in a container enclosed in a gas tight chamber, which consists in continuously supplying liquid refrigerant having a relatively low boiling point into said chamber above the container and causing downward flow of the refrigerant over the walls thereof and preventing formation of gas pockets on said walls while permitting the separation of gases from the liquid, discharging the unused liquid into a receiver, and conveying away the generated gases.

26. In apparatus of the class described, the combination of a closed container, a casing surrounding said container in spaced relation thereto, a reservoir for liquid refrigerant below said casing, a discharge conduit leading from the lower portion of said casing to said reservoir, means for conveying liquid refrigerant from said reservoir to the space between said container and casing and discharging it onto the upper walls of said container, a pipe for supplying the liquid refrigerant to said reservoir, a valve in said pipe outside the walls of said reservoir, a float operated by the rise and fall of the refrigerant level in said reservoir, and operating connections between said float and said valve for operating the latter.

2'1. The herein disclosed process of refrigerating material during agitation thereof in a container surrounded by a closed chamber having a discharge opening which consists in agitating the material and simultaneously supplying a liquid refrigerant having a relatively low boiling point into the upper portion of said chamber and circulating it under pressure over and in contact with the walls of the container and discharging the unused portion of the refrigerant through said opening and utilizing the circulation of the refrigerant to remove from the container walls gases generated by the transfer of heat from the material and simultaneously exhausting from the upper portion of the chamber the generated gases which become separated from the liquid refrigerant. v

28. The herein disclosed process of refrigerating material in a container surrounded by a closed chamber having a discharge opening, which consists in supplying a liquid refrigerant having a relatively low boiling point into the upper portion of said chamber and circulating it under pressure over and in contact with the walls of the container and discharging the unused portion of the refrigerant through said opening and utilizing the circulation of the refrigerant to remove from the container walls gases generated by the transfer of heat from the material and simultaneously exhausting from the upper portion of the chamber the generated gases which become separated from the liquid refrigerant.

29. The herein disclosed process of refrigerating material during agitation thereof in a container surrounded by a closed chamber, which consists in supplying a liquid refrigerant having a relatively low boiling point into the upper portion of said chamber and circulating it over and in contact with the walls of the container, collecting the unused portion of the refrigerant for re-circulating it over and in contact with the cylinder walls and utilizing the circulation of the liquid refrigerant to remove from the container walls gases generated from the transfer of heat from the material and simultaneously exhausting from the upper portion of the chamber the generated gases which become separated from the liquid, and then shutting off the supply of the liquid refrigerant and continuing the agitation of the material to effect whipping thereof.

' 30. The herein disclosed process of refrigerating material during agitation thereof in a container surrounded by a closed chamber, which consists in supplying a liquid refrigerant having a relatively low boiling point into said chamber and circulating it over and in contact with the walls of the container, utilizing the circulation of the liquid over the container, walls to remove therefrom gases generated by the transfer of heat from the material and simultaneously permitting the liquid and gases to separate and exhausting from the upper portion of the chamber the generated gases which become separated from the liquid.

ALBERT T. LIGHT.