US3681937A

US3681937A - Refrigeration system for cold drink machines

Info

Publication number: US3681937A
Application number: US91380A
Authority: US
Inventors: Alan D Barden
Original assignee: Rowe International Inc
Current assignee: Rowe International Inc
Priority date: 1970-11-20
Filing date: 1970-11-20
Publication date: 1972-08-08
Anticipated expiration: 1989-08-08
Also published as: CA923317A; GB1338019A; JPS5127295B1

Abstract

An improved refrigeration system for a machine for dispensing cold drinks with or without ice in which liquid refrigerant is supplied from a compressor through the central tube of a vertically disposed elongated heat exchanger having a surrounding jacket spaced from the tube by a spiral path-forming member alternatively to the upper end of a vertically disposed icemaker evaporator coil or to the upper end of an icebank evaporator coil for return flow of the refrigerant in gaseous state through a gravity system to the upper end of the heat exchanger jacket for flow downwardly along a spiral path in heat exchange relationship with the liquid refrigerant to the suction line of the compressor.

Description

United States Patent Barden 14 1 Aug. 8, 1972 [54] REFRIGERATION SYSTEM FOR COLD 525,224 8/1894 Miles et al. ..62/84 DRINK MACHINES 3,550,392 12/1970 Mitchell ..62/354 2,605,621 8/ 1952 Kellershon ..62/344 UX [72] Invem Q Lake 3,377,815 4/1968 Soderberg ..62/354 x [73] Assignee: Rowe International Inc., Whippany, Primary Examinerwilliam E. Wayner N.J. Attorney -Shenier and OConnor [21] Appl' 91380 An improved refrigeration system for a machine for dispensing cold drinks with or without ice in which 52 US. (:1. ..62/340, 62/84, 62/430, 1 liquid refrigerant is pp from a compressor 2/524 1 5 15 through the central tube of a vertically disposed elon- 51 1111. c1 ..F25b s/oo sated heat exchanger having a Surrounding jacket 58 Field 61 Search ..62/513, 344, 524, 525, 354, Spaced f the tube by W3 P -99 member 62/430 84 alternatively to the upper end of a vertically disposed icemaker evaporator coil or to the upper end of an [56] References Cited icebank evaporator coil for return flow of the refrigerant in gaseous state through a gravity system to UNITED STATES PATENTS the upper end of the heat exchanger jacket for flow downwardly along a spiral path in heat exchange relag :3 tionship with the liquid refrigerant to the suction line u 3,104,835 9/1963 Weber ..241/94 6 3,377,815 4/1968 Soderberg ..62/354 X 11 Claims, 4 Drawing Figures PATENTEDAuc 8 m2 'SHEET 1 OF 2 INVENTOR Allan!) Bar/e77 ATTORNEYS PATENTEUAUG 8 i972 SHEET 2 BF 2 m a M Mr w v0 m mB U 5 n a l BACKGROUND OF THE INVENTION There are known in the prior art merchandising machines for dispensing cold drinks with or without ice. Machines of this type include a water bath in which a carbonated water supply and a still water supply coil are immersed so that the bath serves to cool both still and carbonated water. Associated with the water bath is an icebank evaporator coil to which refrigerant is supplied to cool the tank. Machines of this type also include an icemaker comprising a helical generally vertically arranged evaporator coil to which refrigerant also must be supplied.

In one particular system of the prior art used in a machine of the type described above, liquid refrigerant is supplied from a condenser to a liquid line which runs through a drier to a tee, one outlet of which is coupled to the lower end of the icemaker coil through a solenoid-operated valve and the other outlet of which is connected to the icebank evaporator coil through another solenoid-operated valve. The upper end of the icemaker coil is connected to the compressor suction line through an accumulator while the outlet of the icebank evaporator coil is connected directly to the suction line.

The refrigeration system described above embodies a number of defects. First, owing to the fact that the compressor oil seals are soluble in the refrigerant such as Freon, some oil is entrained with the liquid refrigerant. Consequently, as refrigerant is fed into the lower end of the icemaker coil, oil collects at this location. This oil traps some of the liquid refrigerant. The trapped refrigerant continues to evaporate after the icemaker is shut down and water in the icemaker freezes until, ultimately, the auger is frozen in place. If the icemaker is activated under these conditions, serious damage to the parts may result.

Further in a system of the type described, oil can be trapped at various locations in the system so that ultimately the compressor may be starved of oil and damage thereto can result. Each oil trap also acts as a barrier to the free flow of refrigerant gas' through the suction side of the refrigeration system. In order to overcome the cumulative effect of such barriers a condenser unit of relatively high horsepower is required.

In addition to the two defects discussed above, no effectivev heat exchange is achieved between the hot liquid refrigerant being supplied from the condenser and the cool return refrigerant going to the compressor. Because of this fact, the danger exists, first, of slugging the compressor by feeding liquid refrigerant thereto which results in damage to the compressor. In addition the liquid refrigerant being fed to the system may be excessively hot resulting in damage to the parts of the system required to convey the liquid.

l have invented an improved refrigeration system for machines adapted to dispense cold drinks with or without ice. My system overcomes the defects of refrigerating systems of the prior art which have heretofore been employed on such machines. My system ensures against freeze-up of the icemaker of the machine. It will not starve the compressor of oil. I am able to use a smaller compressor than that required in the prior art to do the same job. It provides effective heat exchange between liquid refrigerant being supplied to the system and refrigerant returning to the compressor. It avoids the danger of feeding liquid to the compressor and of supplying excessively hot liquid refrigerant to the system.

SUMMARY OF THE INVENTION One object of my invention is to provide an improved refrigeration system for a. machine which dispenses cold drinks with or without ice.

Another object of my invention is to provide an improved refrigeration system for a cold drink machine which minimizes the danger of freeze-up of the icemaker.

A further object of my invention is to provide an improved refrigeration system for acold drink machine which ensures eiiective heat exchange between hot liquid refrigerant being fed to the system and refrigerant returning to the compressor.

Other and further objects of my invention will in the following description.

In general my invention contemplated the provision of an improved refrigeration system for a cold drink machine in which hot liquid refrigerant passes upwardly through the central tube of an elongated vertically disposed heat exchanger to a tee from which the refrigerant alternatively is supplied to the upper end of a vertically disposed helical icemaker evaporator coil or to an icebank evaporator coil. After expansion the refrigerant returns from the bottom of the icemaker coil and from the outlet of the icebank evaporator coil to the upper end of the heat exchanger into the space between the central tube and an outer jacket and along a spiral path downwardly through the heat exchanger and back to the compressor.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

FIG. 1 is a partially schematic view of my improved refrigeration systemfor a cold drink machine.

FIG. 2 is an elevation of the heat exchanger of the refrigeration system illustrated in FIG. 1.

FIG. 3 is a sectional view of the heat exchanger shown in FIG. 2 taken along the line 3-3 of FIG. 2.

FIG. 4 is a schematic view of one form of control circuit which can be used with the refrigeration system illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 of the drawings, my refrigeration system includes a compressor 10 to which gaseous refrigerant from a suction line 12 is supplied through a manually operable valve 14. A line 16 leads from compressor 10 to a condenser 18 which supplies liquefied refrigerant through a line 20 to an accumulator tank 22. A manually operable valve 24 connects the reservoir tank to the input line 26 of the refrigeration system. A fitting 28 connects line 29 to a line 30 which fonns the central core of an elongated generally vertiappear cally disposed heat exchanger indicated generally by the reference character 32. After emerging from the upper end'of the heat exchange 32 line 30 is connected by a fitting34 to a liquid refrigerant supply line 36 leading to a tee 38. Preferably I insert a drier 40 in the line 36 ahead of tee 38.

A first line 42 is adapted to connect one outlet of the tee 38 to the upper end of the expansion coil 44 of an icemaker indicated generally by the reference character 46 through a normally closed solenoidoperated valve 48 and an expansion valve 50 which can be adjusted to regulate the downstream pressure in the coil 44. The icemaker per se may be of the type shown in US. Pat. No. 3,196,624.

Another line 52 is adapted to connect the other outlet of the tee 36 to the expansion coil 54 of the icebank system indicated generally by the reference character 56 through a normally closed solenoid-operated valve 58 and a thermostatic expansion valve 60.

The heat exchanger 32 includes an outer tubular jacket 62 spaced from the core tube 30 by a helical wire forming a helical path along the length of the heat exchanger 32 between the upper and lower ends thereof.

Respective return lines

66 and 68 connect the lower end of the coil 44 and the outlet of the icebank evaporator coil 54 to a fitting 70 at the upper end of the heat exchanger 32 so that returning refrigerant passes downwardly along the helical path formed by wire 64. Another fitting 72 at the lower end of the heat exchanger 32 connects the space between core tube 30 and "jacket '62 to the suction line 12 leading to the compres'sorinlet valve 14. A thermostatic element 74 associated with the icebank evaporator coil 54 is adapted to close a normally open switch indicated by the block 76 in FIG. 1 when the temperature of the water bath drops below a predetermined temperature.

Referring now to FIGS. 2 and 3, it will be seen that the diameter of the core tube 30 of the heat exchanger 32 is larger than the diameter both of the exchanger i slower rate than flow through the tubes or

lines

26 and 36. Moreover, the spiral path between the jacket 62 and tube 30 formed by wire 64 ensures a long path of travel for return refrigerant from

lines

66 and 68. These two features of the heat exchanger 32 ensure that the hot liquid refrigerant and the cool returning refrigerant remain in heat exchange relationship for a relatively long period of time. As a result, I ensure that all of the return refrigerant entering line 12 is in the gaseous state so that no liquid refrigerant such as might cause slugging of the compressor is retumedQMoreover, I prevent excessively hot liquid refrigerant from being fed to the line 36. In a particular embodiment of my refrigeration system, the core tube 30 may be made of 36 inch diameter tube, the outer jacket 62 may be made of 36 inch copper tube with a diameter of 0.080 inches for the copper wire 64. In that installation I employ /4 inch tubing for

lines

26 and 36 so as to afford more than the cross sectional area for flow of hot liquid refrigerant through core tube 30 than through the

tubes

26 and 36. It will, moreover, be appreciated that since my heat exchanger 32 requires only two lengths of

copper tubing

30 and 62 and a length of wire 64 together with

appropriate fittings

70 and 72, it may be .constructed in a simple, expeditious and inexpensive manner.

While the system shown in FIG. 1 is somewhat schematic, it can be seen that the arrangement is such that no locations exist at which a substantial amount of oil could be trapped so as to starve the compressor. There is, moreover, no location at which oil can collect and trap liquid refrigerant to result in a freeze-up of the system as occurs at the icemaker in systems of the prior art.

Referring now to FIG. 4, I have shown one form of electrical circuit which may be used to control the operation of the refrigeration system illustrated in FIG 1. I connect respective

power supply lines

78 and 80 to the

terminals

82 and 84 of a suitable source of power. An on/off switch S and a control timer switch CTl connect the icemaker motor 1M across

lines

78 and 80. As is known in the art, switch CT 1 closes in the course of operation of the machine with which the system is as sociated by means of a cam (not shown) to energize motor IM to drive the auger (not shown) of the icemaker 46. Another control timer switch CT2 is adapted to be closed in a similar manner in the course of a dispensing operation to energize the ice delivery solenoid IS of the icemaker to deliver a charge of ice in a manner known to the art.-

When the temperature of the water bath 56 drops below a predetermined temperature, the thermal switch TS indicated by block 76 in FIG. 1 closes. When TS closes it the compressor motor CM and the fan motor FM associated with condenser 18, at thesame time, solenoid 58 is energized through normally closed relay contacts RR2 to open line 52 to the ice-bank evaporator coil 54.-When the temperature of the bath has dropped to a preset level switch TS opens and motors CM and FM, as well as valve 48 are deenergized.

When the level of the ice supply in the icemaker 46 drops to below a predetermined level, a switch ILS closes in a manner known to the art to energize solenoid valve 48 to open line 42. At the same time, a relay winding RR is energized. Relay winding RR closes normally open contacts RRl and RR3 and opens normally closed contacts RR2. Since contacts RR2 are open, solenoid valve 58 cannot be energized, so that line 52 is closed. Closing of contacts RRl energizes the compressor and fan motors CM and FM to supply refrigerant to the system. Closing of contacts RR3 energizes the ice motor 1M. Under these conditions the icemaker 46 makes ice until switch ILS reopens.

The operation of my refrigeration system will be apparent from the description hereinabove. Whenever the compressor motor CM is energized, liquid refrigerant is supplied to the core tube 30 of the heat exchanger 32. If the icemaker supply of ice is below a predetermined level, this liquid refrigerant is supplied to the upper end of coil 44 through the open valve 48 and valve 58 is closed to prevent the flow of refrigerant to the icebank evaporator coil 54. Alternatively, if the icemaker has a full supply of ice but the temperature of the water bath is below the desired temperature, valve 48 is closed and refrigerant is supplied to coil 54 by valve 58. In each case the cross sectional area of tube 30 is greater than that of either line 26 or line 36 so that the hot liquid refrigerant travels at a slower rate through the heat exchanger than through the inlet and outlet lines. At the same time the heat exchanger 32 provides a long spiral path for returning refrigerant so as to maintain the hot input refrigerant and the cooler return refrigerant in heat exchange relationship for a relatively long period of time. Thus, I avoid both the danger of returning liquid refrigerant to the compressor and of supplying excessively hot liquid refrigerant to either of the systems. My refrigeration system includes no traps whereat oil might collect so as to trap liquid refrigerant to cause a freeze-up of the icemaker, for example. The system, moreover, avoids any traps for oil through which return refrigerant might be required to bubble, thus necessitating the use of a heavy compressor providing a high suction or possibly starving the compressor with the resultant danger of burning the compressor up.

It will be seen that I have accomplished the objects of my invention. I have provided an improved refrigeration system for a machine adapted to dispense cold drinks with or without ice. My system minimizes the possibility of freeze-up of components such as the icemaker, for example. It is free of oil traps so that a relatively smaller compressor can be used than is required in the prior art while at the same time reducing the possibility of starving the compressor. My system provides efi'ective heat exchange between the hot refrigerant being supplied and the relatively cooler refrigerant returning to the compressor, thus to avoid returning liquid refrigerant to the compressor and feeding excessively hot liquid refrigerant to the distribution systems.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

' Having thus described my invention, what I claim is:

1. A refrigeration system for a machine adapted to dispense cold drinks including in combination, a heat exchanger having a compressed refrigerant fluid inlet and a compressed refrigerant fluid outlet and an expanded refrigerant fluid inlet and an expanded refrigerant fluid outlet, means including a compressor and a condenser for receiving expanded refrigerant fluid and for delivering compressed refrigerant fluid, means for conveying compressed refrigerant from said condenser to said compressed fluid inlet, an ice bank evaporator coil, a generally vertically disposed icemaker evaporator coil, means adapted to be actuated alternatively to connect said compressed fluid outlet to said ice bank evaporator coil and to the top of said icemaker coil, means connecting said ice bank evaporator coil and the bottom of said icemaker coil to said expanded fluid inlet and means connecting said expanded fluid outlet to said compressor.

2. A refrigeration system is in claim 1 in which said heat exchanger is arranged with said compressed fluid inlet and said expanded fluid outlet adjacent the bottom thereof and with said compressed fluid outlet and s edfl 'd'nl tad' t to f.

mg We gera on sy teni i r i l i r i zflfich said paths for conducting fluids is heat exchange relationship, said heat exchanger being arranged with the compressed fluid inlet and the expanded fluid outlet adjacent the lower end thereof and with the compressed fluid outlet and the expanded fluid inlet adjacent the upper end thereof.

5. A refrigeration system as in claim 1 in which said means connecting said lower end of said icemaker coil to said expanded fluid inlet provides a gravity path.

6. A refrigeration system as in claim 1 in which the construction of said heat exchanger is such as to slow the rate of flow of fluid between said compressed fluid inlet and said compressed fluid outlet.

7. A refrigeration system as in claim 1 in which said heat exchanger comprises means forming a straight vertical path for the flow of compressed fluid between said compressed fluid inlet and said compressed fluid outlet and means forming a tortuous path for the flow of expanded fluid between said expanded fluid inlet and said expanded fluid outlet, the flow of expanded fluid being countercurrent to the flow of compressed fluid.

8. A refrigeration system as in claim 1 in which said heat exchanger comprises a central tube extending generally vertically from said compressed fluid inlet to said compressed fluid outlet and a surrounding tube forming a space extending between said expanded fluid inlet and said expanded fluid outlet.

9. A refrigeration system as in claim 1 in which said heat exchanger comprises a central generally vertically extending tube, an outer tube surrounding said innertube in spaced relationship thereto and means forming aspiral path in the space between said tubes, said heat exchanger being arranged with the hot fluid inlet adjacent to the lower end of said central tube and the hot fluid outlet adjacent to the upper end of said central tube and with the cool fluid inlet adjacent to the upper end of the space between said tubes and the cool fluid outlet adjacent to the lower end of the space between said tubes.

10. A refrigeration system as in claim 9 in which said means for conveying refrigerant to said hot fluid inlet and said means for connecting said hot fluid outlet comprises tubes having a smaller diameter than that of said central tube.

11. A refrigeration system as in claim 9 in which said spiral path forming means comprises a helical element in contact with the outer surface of the central tube and in contact with the inner surface of the outer tube over the lengths of said tubes.

Claims

2. A refrigeration system is in claim 1 in which said heat exchanger is arranged with said compressed fluid inlet and said expanded fluid outlet adjacent the bottom thereof and with said compressed fluid outlet and said expanded fluid inlet adjacent the top thereof.

3. A refrigeration system as in claim 1 in which said heat exchanger provides generally vertically extending paths for conducting fluids in heat exchange relationship

4. A refrigeration system as in claim 1 in which said heat exchanger provides generally vertically extending paths for conducting fluids is heat exchange relationship, said heat exchanger being arranged with the compressed fluid inlet and the expanded fluid outlet adjacent the lower end thereof and with the compressed fluid outlet and the expanded fluid inlet adjacent the upper end thereof.

9. A refrigeration system as in claim 1 in which said heat exchanger comprises a central generally vertically extending tube, an outer tube surrounding said inner tube in spaced relationship thereto and means forming a spiral path in the space between said tubes, said heat exchanger being arranged with the hot fluid inlet adjacent to the lower end of said central tube and the hot fluid outlet adjacent to the upper end of said central tUbe and with the cool fluid inlet adjacent to the upper end of the space between said tubes and the cool fluid outlet adjacent to the lower end of the space between said tubes.