US2267819A - Refrigeration apparatus - Google Patents

Description

c. v. DI PIETRO REFRIGERATION APPARATUS Filed May 31, 1958 2 Sheets-Sheet l |N VENTOR A ORNEY Dec. 30, 1941. c. v. DI PIETRO 2,267,819

REFRIGERATION APPARATUS Filed May 31, 1958 2 Sheets-Sheet 2 INVENTOR TTORNEY Patented Dec. 30, 1941 UNITED STATES PATENT -OFFICE REFRIGERATION APPARATUS Carmelo V. Di Pietro, Birmingham, Mich. Application May 31, 1938, Serial No. 210,807

13 Claims.

This invention relates to heat exchange systems and more particularly to systems for mechanically refrigerating liquids to be drunk at dispensing stations.

Such systems include a compressor connected to a cooling unit through which the liquid to be dispensed flows under pressure from a source of supply to the dispensing faucet. The refrigerating systems are usually of the flooded or dry type, and this invention has to do primarily with the dry type system in which refrigerant is released to the cooling unit in an expanded condition by a thermostatically controlled valve.

It is desirable with many installations that the cooling unit be disposed adjacent the dispensing faucet in a very limited space, but heretofore this has been impossible because the size of the cooling unit that would maintain liquid at a desired temperature with rapid dispensing has been prohibitive. The storage space in the cooler and the heat transfer wall area required to maintain a given temperature of rapidly dispensed liquid during the first part of the compressor operation in each cycle of operation has necessitated a cooler having dimensions that have been prohibitive to its use in many installations in a space adjacent the dispensing faucet.

Installation of the cooling unit remote from the dispensing faucet reduces the efficiency of the system because the temperature of the cooled liquid rises in moving from the cooler to the faucet. In soda fountains, for example. the cooling unit has consisted of coils of a bulky nature that have been arranged in one of the food stor age compartments a considerable distance from the liquid dispensing faucets, thereby reducing the capacity of the storage space in the compartment and requiring more work by the compressor in maintaining a desired liquid temperature at the faucet because of the heat picked up by the liquid between the cooler and the faucet.

An object of the invention is to provide a mechanical refrigerating system for liquid to be dispensed at a station with a dry type cooling unit constructed in a manner such that it is small enough to be located adjacent the outlet and capable of storing a quantity of cooled liquid sufficient to meet the volume and temperature requirements at the station between and during the first part of the operating heat transfer cycles of the system.

Another object of the invention is to provide a unit for cooling citrus juices and carbonated water in which the heat transfer elements are jointless and formed of low cost metal that can be plated and readily inspected prior to assembly.

A further object of the invention is to provide a liquid cooling unit that minimizes the possibility of damage from freeze-up when the refrigerant control fails to function properly.

It is another object of the invention to provide a mechanical refrigeration liquid cooling unit of relatively small dimensions having a large liquid capacity and designed to maintain the liquid therein in a progressive path of flow therethrough so that incoming warmer liquid will not intermingle with the cooled liquid.

A still further object of the invention is to regulate the refrigerating effect of a liquid cooler so that the temperature of the dispensed liquid will remain substantially constant with a rela tively high rate of flow.

Another object of the invention is to control the opening and closing of an expansion valve in a refrigerating system by'thermostat means responsive to conditions in both the refrigerant inlet and return lines immediately adjacent the cooling unit.

Another object of the invention is to provide a cooling unit in a mechanical refrigerating sys-- term that will maintain two liquid dispensing systems at the same temperature while utilizing a single expansion valve and a single suction pressure control valve.

In=-order that the invention may be clearly understood and readily carried into effect, it will now be described more fully with reference to the accompanying drawings, wherein:

Figure 1 is a fragmentary elevational view of a soda fountain, partly broken away, with a cooling unit incorporating the invention shown in operating position;

Figure 2 is a vertical sectional view taken on line 2--2 of Fig. 1;

Figure 3 is an end view of a cooling unit for two liquids taken approximately on line 3-3 of Fig. 1;

Figure 4 is a view, broken away and partly in section, of one of the sections of the cooling unit;

Figure 5 is a longitudinal sectional view through a cooling unit comprising two sections for cooling two liquids having the remainder of the refrigerating system shown diagrammatically;

Figure 6 is an end view of the cooling unit shown in Fig. 5;

Figure 7 is a view partly in elevation and partly in section of a liquid cooling unit composed of one section;

Figure 8 is an elevational view of the cooling unit shown in Figs. 1, 2 and 3;

Figure 9 is an enlarged fragmentary end view of the control means in Fig. 8;

Figure 10 is a sectional view of th control means taken on line Ill-l of Figure Figure 11 is a sectional view of the control means taken on line llll of Fig. 5. 1

The refrigerating system forming the subjec matter of this invention is shown installed with a conventional soda fountain, indicated generally by numeral 20, but the system may be installed equally as well with various other types of liquid dispensing stations. Soda fountains usually consist of a frame having an exterior wall 2| and a wall lining 22 of insulating material. The base portion is usually divided into separated compartments, the compartment 23 being utilized to store bottled liquids and food requiring a medium low temperature. Theother compartments are usually utilized for storing ice cream and food requiring a low temperature. Access is had to the compartments through openings in the rear or top of the base portion, such openings being closed by suitable doors or covers 24. Above the forward portion of the base is an upper structure having a counter top 25 along the front portion thereof and an enclosed storage space 26 for receiving jars 21 adapted to contain fruit syrups and flavoring liquids.

A plurality of liquid dispensing stations are associated with the fountain and two such stations are illustrated. A conduit 28 leads into the cabinet from a source of drinking water under pressure, not shown, and a conduit 29 leads into the cabinet from a source of carbonated water under pressure, not shown. Dispensing arms 30 and 3| extend above the fountain top and faucets 32 are associated therewith to control liquid flow through conduits 50 and 59 leading through the arms.

With such cabinets there is usually associated one or more mechanical refrigerating systems each of which employs a compressor 53 and refrigerant conduits leading to one or more cooling units or evaporators located in the cabinet base compartments. It has been the practice to lead the fluids to be dispensed in heat transfer relation with the evaporator or cooling unit in the storage compartment in which the highest temperature is maintained. Because of the distance the liquids must flow after leaving the cooling unit, their temperature rises considerably and hence they must be cooled several degrees below the desired dispensing temperature. This places more of a burden on the compressor of the refrigerating system so that efficiency is impaired and when the fluid volume dispensed is rapid, then the temperature of the dispensed liquid be comes too high unless the cooler is of larger overall dimensions. In addition to this, the size of the heat transfer unit required to cool the liquid reduces the space available for food or bottle storage in the compartment, and the arrangement furthermore limits the cooling temperature in the compartment to that required for cooling the dispensable liquids at a desired temperature, usually about 40.

These undesirable characteristics and disadvantages encountered with cooling units for cooling dispensed liquids are substantially eliminated by this invention, wherein a relatively large liquid storage capacity and heat transfer wall area is provided within small dimensions. As a result, the unit can be arranged close to the dispensing faucet at stations and will deliver the cooled liquid at the desired temperature even though the rate of flow is rapid.

The cooling unit, because of its small size, can bearranged in the previously wasted space in the jar compartment 26 of a soda fountain and, besides cooling liquid to be dispensed, the exterior surface will serve to cool the jar compartment.

In Figs. 4 and 7 is illustrated a single unit cooler forming the heat transfer portion of the mechanical refrigerating system. It is comprised of three telescoped tubes 34, 35 and 36 formed of metal having efiicient heat conducting characteristics. The inner tube 34 is preferably formed of stainless steel with a groove extending spirally its entire length while the tubes 35 and 36 may be formed of brass, aluminum, copper or other material, the tube 35 being provided with a spirally extending fin. The fin can either be attached to the tube or protruded therefrom, but I prefer to use the protruded fin because there will be no joint, and as it will be absolutely smooth better heat transfer conditions result and further, the protruding operation leaves a spiral recess in the tube. The spiral recess in the tubes 34 and 35 allows for expansion so that there will be less likelihood of a freeze-up rupturing the tube and will guide the liquid in a spiral progressive path in passing through the cooler. The protruded finned tube has the further advantage that it can be plated more readily and efliciently than tubes on which the fin is attached. The contact of citrus juices and carbonated water with the lower priced metals creates a chemical reaction that is injurious to the drinker so these metals must be plated or a more expensive metal such as stainless steel employed for this purpose. With the present construction this plating with nickel and silver can be done on the copper tubes before their assembly in the cooling unit so that inspection can be readily made and as they are jointless the plating is desirable. Heretofore the constructions of coolers have been such that the plating has necessarily been done after assembly of the cooler elements and difliculty of accurate inspection has almost usually forced the use of more expensive metal that does not have to be plated, such as stainless steel.

The spiral fin on the tube 35 is formed of a radial dimension so that it contacts .the inner face of the outer tube 36. Between the two inner tubes 34 and 35 is arranged a spirally extending member 38, in the form of a tube as shown in Figs. 4 and '7 and in the form of a rod as shown in Fig. 5. In either case the diameter of member 38 is such that it thermally contacts the adjacent tubes throughout its length. The tubes are fixed at their ends to headers or caps 39 and 40, thus forming between the tubes three annular separated compartments or chambers 4|, 42 and 43. The inner tube 34 extends through the headers and the ends are suitably secured thereto in leak-proof relation. A fitting 49 extends into passage 48 in header 33 and has the conduit 28 fixed thereto, such conduit leads from a supply of water under pressure (not shown). The other end of the chamber 43 connects with a passage 46 in header 40 and a U-coupling is fixed in this passage and has its other end fixed in the header 40 in communication with tube 4|. A

fitting 44 extends into header 39 and connects tube 4| with conduit 50 leading to arm 3|. A fitting 5| is screwed into the header 40 and communicates with the compartment 42, such fitting having a refrigerant conduit 52 connected thereto leading from the compressor 53, shown in Fig. 5. Another fitting 54 is screwed into header 39 and communicates with the compartment 42, such fitting having the refrigerant conduit 55 leading to the compressor connected thereto. When the spiral member 38 is in the form of a rod, it is of a length to be entirely contained within the compartment 34. When the spiral member 38 is in the form of a tube, as in Figs. 4 and 7, it can be extended through the headers 39 and 46 and a fitting 56 is fixed to one end thereof and has a liquid supply line 51 connected therewith. To the other end of the tubular spiral member 38 is fixed a fitting 58 having an outlet line 59 connected thereto leading to a faucet arm 36 or other dispensing means.

In the refrigerant return line 55 between the compressor and the cooling unit is interposed a conventional form of suction pressure valve 60. In the refrigerant supply line 52, between the compressor and the cooling unit, is interposed a conventional form of expansion valve 6| adapted to be thermostatically controlled. Such valves are shown diagrammatically in Fig. 5. The cooling units in Figs. 2 and 4 are shown full size and the heat transfer surface area and small overall dimensions can be visualized. In Fig. 7, the outer tube 36 is shown as having a spiral fin 62 extending from the outer face thereof, and this form of tube may be utilized when it is desired to transfer a relatively large volume of heat from the space in which the unit is installed.

In Fig. 5 the cooler is shown as comprising two units A and B, each of which is formed substantially the same as the single unit previously described. In this form of the invention the headers 40 are connected by a tube 63 having its ends communicating with the refrigerant containing compartments 42 and the refrigerant inlet fitting is associated with the header 39 of unit A while the refrigerant outlet fitting is associated with the header 39 of unit B. The headers 39 are fixed together by suitable means, such as tube 65. The refrigerant conduits are connected with such fittings and the compressor as previously described. Liquid inlet fittings 44 and 56 are fixed in the header 39 of unit B, fitting 44 communicating with compartment 4! and fitting 56 communicating with compartment 43 of such unit. U-connector tubes 66 and 61 have their ends fixed to the headers 40 of units A and B, the connector 66 communicating with compartment 4| in unit A and compartment 43 in unit B while connector 61 communicates with compartment 4| in unit B and compartment 43 in unit A. Unit A has the two outlet fittings 49 and 58 connected in the header 39, andconduit 50 leads from fitting 49 to one dispensing station in arm 3| and conduit 59 leads fromthe fitting 58 to another dispensing station in arm 30.

In Figs. 1, 2, 3, and 8 is shown still another form of the invention particularly adapted for use with soda fountains. This cooling unit is similar to that shown in Figs. 5 and 6 and differs therefrom by having means for increasing the through a cooling unit C in returning to the compressor. In other words, the cooling unit 0 is interposed in the return line 65. Such unit 0 is preferably in the form of an externally finned tube 86 having an inlet fitting 8| at one end and an outlet fitting 82 at the other end, such fittings being connected to sections of the return refrigerant line 55. This cooler C is shown placed above the units A and B which substantially align vertically, the arrangement being such that the complete cooling unit can occupy the formerly wasted space behind the syrup jars in the compartment 26 with the liquid outlets in close proximity to the dispensing faucets.

In mechanically refrigerated systems of the dry type for cooling liquids, the bulb of the thermostatic system for actuating the expansion valve to release refrigerant to the cooler is usually arranged in thermal contact with the refrigerant return line. With such arrangement the refrigerating system functions only indirectly in response to liquid temperature and I propose to improve this condition in order to maintain a more even dispensing temperature of the liquid. As best shown in Figs. 9 and 10, a bulb of a conventional thermostatic expansion valve control is in contact with the refrigerant inlet line 52 and with the refrigerant outlet line 55, such relation bein maintained by a metal clamp Ill. The contact is made with the refrigerant supply line between the cooling unit and the expansion valve. In order to further assist in obtaining a more even temperature of dispensed liquid, it is proposed to make a thermal contact between the beverage inlet conduits and the refrigerant inlet line between the expansion valve and the cooler. To this end the refrigerant line is clamped against the liquid supply lines 28 and 29 leading to the cooling unit and the refrigerant supply line by a clamp 82, as best shown in Figs. 5 and 11.

The form of cooling unit herein described has many advantages over those previously employed with liquid dispensing systems. As shown by the full size views of the units in Figs. 2 and 4, it is obvious that overall dimensions are relatively small so that installation can be made in a small space. This is important with dispensing stations as it allows the unit to be placed close to the dispenser. Because of its compactness the unit can be located in the normally unoccupied jar space of a soda fountain and close to the dispensing faucets to thereby increase the efllciency of the refrigerating system which must otherwise operate oftener because of temperature rise w-th a more remote installation. Also the location of the unit in a soda fountain allows the space formerly occupied in the food storage compartmentto be utilized for food, and also allows the food storage compartment to be cooled to a lower temperature than is possible when the liquid cooling unit is located in such compartment. The unit also will displace other cooling means in the jar space of a fountain and when the outer tube is finned then of course a greater heat transfer from the jar compartment results. The heat-is transferred from the space in which the unit is installed through the outer tube and the finned intermediate tube to the refrigerant, the contact of the fins 3-1 with the outer tube servingielficiently for this purpose.

The spiral recesses in the two inner tubes of the cooling unit provide additional heat transfer surfaces as compared with plain tubes, they assist in moving the liquids progressively through the cooler, and they reduce the hazard of a freeze-up upon failure of the suction control valve as they will allow greater liquid expansion without bursting the tubes. As before related, these tubes can be plated and accurately inspected before assembly so that they can be formed of low priced material, and the protruded fin allows smooth and accurate plating and maximum heat transfer. The elements of the cooling unit can be fabricated at low cost and readily assembled. The spiral fin on the intermediate tube gives a large heat transfer wall area and serves to guide the liquid in a progressive path of travel so that the incoming warmer liquid does not mingle with water already cooled in the storage chamber, thereby preventing the heating of the cold water. The large storage capacity of the cooler serves to aid the maintenance of definite exit beverage temperature.

Through means of the extensive wall area of the relatively small unit and the large liquid storage capacity thereof, there will be suilicient cooled liquid to meet the demands of the dispensing station, even when the flow is rapid, while the refrigerating system lags in its refrigerating ability at the first part of the operating cycles. The cooler controls both the refrigerant and liquid flow in a manner to provide an even dispensing temperature for the liquid although the overall dimensions are relatively small.

The liquid moves partly in an opposite direction to the refrigerant flow in the single cooler while in the double unit the liquids and the refrigerant flow entirely in opposite directions through the cooler. With this arrangement of the two unitsfi a plurality of liquids can be cooled and dispensed at an even temperature in a manner that requires only one expansion valve and one suction pressure control valve.

Various changes can be made in the embodiments of the invention as herein shown and described without departing from the spirit of the invention and the scope of the following claims.

What I claim is:

1. A liquid cooler comprising two tubes telescopically associated to form two separate closed chambers, a refrigerating system connected with the outer chamber, a dispensing drinking liquid system connected with the inner chamber, a tube extending spirally in the outer refrigerant chamber, said spirally extending tube thermally contacting said telescopically associated tubes and defining therewith a spiral refrigerant passageway through the outer chamber, and a liquid dispensing system connected with the interior of the spirally extending tube.

2. A liquid cooler comprising two sets of three telescoped tubes, the tubes of each set being associated to form three separate chambers, means connecting the outer chamber of one of a first set in series with the inner chamber of the second set of chambers, means connecting the inner chamber of the first set in series with the outer chamber of the second set, a connection between the intermediate chambers of the sets, a refrigerating system connected with the intermediate chambers, and two dispensing fluid systems connected one with each series of connected chambers.

3. A liquid cooler comprising two sets of three telescoped tubes, the tubes of each set being associated to form three chambers, an end connection between the intermediate chambers of said sets of tubes, a refrigerant line leading into one of the intermediate chambers at the end opposite the connection, a refrigerant line leading from the other intermediate chamber at the end opposite the connection, connections adjacent said refrigerant connector between the outer chamber of one set and the inner chamber of the other set. two liquid inlet lines connected with the end of one set remote from the connectors, one of said lines communicating with the inner chamber and the other with the outer chamber, and two liquid outlet lines connected with the end of the other set remote from the connectors, one of said outlet lines communicating with the inner chamber and the other outlet line communicating with the outer chamber, the liquids flowing through the cooler inthe opposite direction to the refrigerant flow.

4. A liquid cooler comprising three telescoped tubes forming three separate chambers, a refrigerant line connected to the intermediate chamber, liquid lines connected with the inner and outer chambers, and spirally coiled tubing in the refrigerant chamber in thermal contact with the tubes forming the chamber, and a liquid line connected with said spiralled tubing.

5. A liquid cooler comprising three telescoped tubes forming three chambers, refrigerant inlet and outlet lines connected to opposite ends of the intermediate chamber, liquid connections with the inner and outer chambers, and an externally finned heat transfer chamber connected in the refrigerant outlet line.

6. A liquid cooling unit comprising a set of three spaced telescoped tubes, a header at each end of said set, a connection adjacent one of the headers directly joining the inner and outer spaces formed by the tubes, inlet and outlet liquid connections leading to the said inner and outer spaces through the other header, and a refrigerant inlet and outlet open to the intermediate space formed by the tubes.

7. A liquid cooler comprising two telescoped tubes forming two chambers, one of said tubes being formed with a spiral groove extending axially thereof, means connected with the chamber in which the groove opens to pass drinking liquid therethrough, and a refrigerating system .line connected with the other chamber.

8. A liquid cooler comprising three telescoped tubes forming three separate chambers, a refrigerant line connected to the intermediate chamber, spirally coiled tubing in the intermediate chamber, and drinking liquid dispensing means connected with the inner and outer chambers and with the spirally coiled tubing.

9. A liquid cooler comprising three telescoped tubes forming three chambers, drinking liquid dispensing means connected with the inner and outer chambers, a heat transfer chamber connected with the intermediate chamber out of thermal contact with the other chambers, and a refrigerating system connected withthe intermediate chamber and heat transfer chamber.

10. A liquid cooler comprising two telescoped tubes forming two separate chambers, the inner tube having a spiral groove formed in the inner wall surface thereof, means thermally contacting the tubes, a refrigerating system connected to the outer chamber, and a drinking liquid dispensing system connected to the inner chamber.

11. A liquid cooler comprising three coextensive telescoped tubes closed at their ends and forming three chambers, a mechanical refrigerating system connected with the ends of the intermediate chamber, means in said intermediate and outer chambers in thermal contact with the adjacent tubes and forming therewith spiral passages, means connecting the ends of th inner and outer chambers adjacent the refrigerant inlet end of the intermediate chamber, and a source of drinking fluid under pressure connected to the inner and outer chambers with the inlet and the outlet at the ends adjacent the refrigerant outlet end of the intermediate chamber, the flow of liquid being through the spiral passages and in opposite directions through the inner and outer chambers.

12. A liquid cooler comprising a plurality of tubes forming three co-extensive chambers, heat transfer means in the two outer chambers thermally contacting the tubes forming such chambers throughout their length, means connecting the intermediate chamber with a mechanical refrigerating system, means directly connecting one end of the inner and outer chambers, a supply line for drinking liquid under pressure leading into one of the connected chambers, and a drinking liquid outlet line leading from the other of the connected chambers, the inlet and outlet lines for the liquid being at adjacent ends of the chambers with which they are connected.

13. A liquid cooling device comprising two telescopically associated tubes forming two separate chambers, means attached to the ends of the tubes for closing the chambers, a refrigerating system connected with the outer chamber through the closing means, a dispensing drinking liquid system connected with the inner chamber through the closure means, a tube extending spirally through the outer chamber, and a liquid dispensing system through the closure means with the spirally extending tube.

. CARMELO V..DI PIEI'RO.

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