US2143961A - Refrigerating apparatus - Google Patents

Description

Jan. 17, 1939. A. T. sTocK 2,143,951

REFRlGERATING APPARATUS Filed May .9, 1935 Patented Jan. 17, 1939 v UNITED STATES PATENT OFFICE" 2,143,961 BEFRIGERATING APPARATUS Anthony '1'. Stock, Muskegon, Mich assignor to Commercial Coil & Refrigeration 00., Chicago, 111., a corporation of Illinois Application May 9, 1935, Serial No. 20,616 12 Claims. (01. 82-141) which the applicant proposes to overcome.

The flooded type, which is extensively used, contains a comparatively large amount of liquid refrigerant, forming a liquid bath into which there is submerged a coil or coils of tubing conveying a liquid to be cooled. when this bath of refrigerant is in a warm state, and it is desired to cool it to serve a cooled beverage, it produces a tremendous load on a compressor and requires a long time for it to be lowered to the proper temperature. lowered in temperature to a point where it will freeze the beverage contained in the coil, a long time is required to raise the temperature to a point where it will thaw the beverage.

Furthermore, if it is attempted to clean th coil with a hot solution, a very dangerous pressure will be developed within the system and serious damage may result, because the whole bath is subject to a high heat. If the bath of refrigerant were pumped down, that is, removed from the cooler to some other part of the system and stored temporarily, then a hot solution of water or steam could be used without any serious results. This,

however, is a long job and if hurried by the application of heat, must be done with care otherwise serious damage may result during the pump-down process. The cooler as a rule is shipped already charged with the refrigerant, otherwise there would be the necessity, after being installed, 0t draining the charge fromthe compressor unit, which would in turn have to be recharged. When A the unit is shipped and fully charged, it sets up causes a temperature lag on account of the refrigerant having to absorb heat through two walls.

-' Still another, is the refrigerant tube placed in a sweet water'or brine bath which acts as a heat transfer agent between the coils. This last mentioned type is less efiicient than the tubeagainst a tube principle, because there is a greater temperature l g. the heat from the beverage having to be conducted through the wall, through the bath, and through the wall of the refrigerant tube. The bath serves as a hold-over. If the demand is On the other hand, if it should be great enough to overcome the bath temperature and cause it to rise, the result will be a warmer beverage, because while the machine runs under these conditions, the heat from the beverage must go through the bath before being absorbed by the refrigerant.

In each of the last three types described, the refrigerant coil is connected directly to the suction line to the compressor. and when the coil has some liquid refrigerant entrapped within, which is the most emcient operating condition for the direct expansion type, sudden boiling will tend to force or drive it past the eilective surface, at times, and cause a frosting beyond the beverage cooling portion of the coil. The velocity of the gas being very high will make the refrigerant travel faster than it can pick up heat and be dissipated into a gas.

In this invention, being of an improved form, there are coils of tubing spirally wound in tiers having side walls, the refrigerant being conveyed through tubes from its source to a point between the coil turns and between the side walls where it is put into direct contact with the heat laden beverage coil and not allowed to expand or spray into the chamber proper and come in contact with other parts which have little or no bearing on the cooling process, before-it has contacted the beverage coil. After it is deposited on the coil, and while absorbing heat, it flows through channels by gravity along a directed path in contact with the tubing and prevented from falling away by the side walls placed against and snugly fitted to the tubing both inside and out of each tier. As the refrigerant is dissipated into a gas, it is deposited into the chamber proper which acts as an expansion chamber slowing up the velocity of the gas. From there the compressor collects and compresses it. This gas chamber acts to break up a direct small conduit to the compressor as in the case of direct expansion.

Having a thermo bulb placed in the direct path of the refrigerant and the refrigerant being confined between the side walls and on top of the tubing, it will flow toward the bulb and when reaching it will lower the temperature of the thermal medium within the bulb, lowering its pressure which is transmitted to a liquid controlvalve thereby stopping the flow of refrigerant. The thermo bulb is so located that it is effectively formed by the incoming liquid. This causes the liquid valve to open and tend to keep it open, and the capacity of the refrigerant flowing over it will overcome the opening effect and cause it to close.

An example of the bulb action under ordinary operation is as follows: Suppose the outgoing beverage temperature is set at 40 F. and the incoming temperature is, 60 F. then while the refrigerant is not flowing. the beverage is set in motion, the temperature of the beverage near the bulb may be 58 or 59 approximately, a slight reduction being caused by natural conduction, this temperature causing the bulb to warm up, in turn opening the liquid refrigerant valve and start the refrigerant flowing. When the refrigerant flows down the tube'and contacts the bulb, it will lower the temperature of the thermal charge to a lower point than the temperature of the beverage at that point where the bulb contacts the coil, and cause the liquid valve to close, although the beverage temperature near the bulb location may be only 48 or thereabouts. Therefore as long as the beverage-which may be between 50 and 60 F.is flowing, it constitutes the load and permits the liquid refrigerant to be cut in or even cut out since the liquid refrigerant temperature at the bulb will predominate. However, when the beverage flow is stopped and the refrigerant attacks the bulb, the beverage temperature near the bulb may lower to 40 F.

On the other hand, if a beverage had an incoming temperature of 40 F. that is the temperature to which the bulb would be subjected, consequently no refrigerant would be ushered in. If a bulb is placed in a bath and affected by a bath-temperature change, it will open and close on a 3 or 4 differential, on account of the mass of liquid causing a slow action. The same valve control mechanism is used in either case, except that the applicant's system provides the extremes in temperature change for controlling the refrigerant on and off. The change from one extreme to the other is made so rapidly that a balanced temperature at the outlet is obtained, due

to the rapid heat pick-up of the refrigerant when discharged on the coil. The wide range of temperatures controlling the bulb temperature, causes an overrunning of the pressures required to open and close the refrigerant supply valve, this making a morepositive valve action. However, if the load is great enough to prevent the refrigerant from reaching the bulb, it will flow continuously until such time when the load is reduced or the load stopped entirely.

If the refrigerant were allowed to fall between the tiers or float around in the chamber by not having side walls, a loss of efficiency would result. Because the pressure is the same, both inside and out of the refrigerant channels, there cannot be any forcing action to drive the refrigerant through its confinement at a faster rate than it is dissipated into gas as though there were a lower pressure in the chamber.

In the case of cleansing the coils, a hot solution may be used, because there is no bath of refriger ant such as in the flooded type, and if the solution is hot enough it will boil the refrigerant as fast asit is deposited on the coil. When the cleansing is through, the refrigerant simply flows down the coil until it overcomes the high temperature of the bulb and closes the valve by the reduction of pressure within the thermal system. There cannot be any more load on the system than the amount of refrigerant flowing through the valve. The instantaneous action and direct contact of the refrigerant on the coils makes for a very quick cooling of the beverage immediately after cleansing.

In the case of shipping, it can be transported with safety, because all that is necessary is to have a slight pressure of gas to be used as a holding charge. A compression unit having a charge of say ten pounds of refrigerant, will have enough to operate several coolers of this type without any additional refrigerant after the coolers are in- -within the beverage coils ll.

stalled for service, as the amount required to actually function in this cooler is very small, due to the fact that the refrigerant is delivered directly to the heat load upon entering the cooler.

An object is to provide a beverage cooler requiring a minimum of refrigerant to operate.

Another object is to make a multiple of coolers having individual gas chambers whereby it will provide beverages of different temperatures with a proper valving means. This can be done by using the outer wall of one chamber as the inner wall of another chamber.

Another object is to eliminate the direct flow of a refrigerant through a conduit into the return line of the compressor, by having the ex panded refrigerant collect in a chamber.

Another object is to provide a means of conducting a refrigerant in contact with the beverage coil direct.

Another object is to provide a beverage cooling means having a refrigerant conduit with pressures the same interiorly and exteriorly throughout the cooling portion, thereby eliminating a pressure-differential efiect on the liquid refrigerant within the conduit.

In the drawing:

Figure 1 shows a sectional view of the coil tiers enclosed within a chamber embodying this invention.

Figure 2 shows a section along line 2-2 of Figure 1 how the refrigerant may be conveyed from a suitable valve to the beverage coil.

Figure 3 shows a method of holding the coils to their proper spacing.

In Figure 1, a housing 5 forming the outer wall and 6 forming the inner wall, and at the top of these walls is a plate I, and at the bottom a plate 8, these members being properly secured to form a gas tight chamber In. Within chamber l0, tubing ll of any desired sectional shape, wound spirally, is formed in any number of tiers l2. These tiers may be individual, multiple, or in series, with convenient inlets as shown at I4, and with suitable valved outlets such asshown at I5. The coil tiers l2, are provided with vertical side walls 16, butted against the tubing H, and thoroughly surrounding them. These walls form channels ll, through which a refrigerant flows. The channels direct the refrigerant and prevent it from falling or splashing into chamber In while flowing down the tubing. The refrigerant flows by gravity and dissipates as it flows along the tube while in the act of picking up heat from As the refrigerant is evaporated it is converted into a gas and exhausted into the chamber II), from the channels. From there it is taken through the tube 20 which is connected near the bottom of the chamber and conveyed to a compressor which may be of any known type. A valve 22 for controlling the refrigerant is conveniently placed, and a tube or tubes 23 leading from the valve may be used to convey the refrigerant to the inside of the cooler directly to each tier where it is deposited on the coils at or near the top. The injection point of the refrigerant is provided with a shield so it will prevent liquid refrigerant from splashing over into the chamber III. A plate 24 covering the channel near the injection point serves this purpose. -The refrigerant also can be injected further down and between the tubing wherein the tube will act as a guard against the refrigerant splashing into the chamber. The injection points can be conveniently located to suit the speciflc'design of the cooler. The refrigerant may be conveyed to the valve through a pipe 25.

Any desired number of tiers may be placed within the chamber, and other chambers may be added making a multiple of individual coolers,

using one compressor of the proper capacity, each chamber being individually controlled with the proper valving. This allows for getting individual and different temperatures in different kinds of beverages. Each valving means is provided with a thermo control bulb 30, which is conveniently located at a point on the coil directly in the thermo system.

in the inner wall serves to reduce the gas space within the chamber which enables the pressure to be changed more rapidly;

If a coil unit is made in a single tier, the refrigerant flows toward the inlet as it approaches the bulb. In the case of a coil wound in such a way as to cause the beverage flow to be reversed, alternately, with respect to the direction of the refrigerant flow, the refrigerant will flowin a direction with the beverage on a part of the coil unit and in an opposite direction on another part. The walls being snugly fitted to the tubing and subjected to the refrige ant temperature, have in themselves a heat-conducting action, from a point on the tubing where the refrigerant does not contact.

It is evident from, the drawing that the cooler is of the counterflow type wherein refrigerant and beverage move in opposite directions. 'The refrigerant must be fed'so that itmay flow by gravity while cooling. The beverage is fed into the system at or beyond the refrigerant conduit "discharge end.

valve with its operating mechanism formsa control system for supplying liquefied refrigerant to the cooler coil or shutting ofi the supply. Thus the control valve is operated by temperature changes in the bulb to cut in or cut out the refrigerant supply.

The control system of which the bulb forms part ordinarily operates with a substantially fixed temperature differential over a temperature range: and by adjustment this differential may be moved over the range as desired. The upper end of the temperature differential. will be the cut inor valve opening temperature. This may, for example, be about 43 F. The lower end of this differential will be the cut out or valve closing temperature. This may be any temperature below the out in temperature, in this case 43 F., and above the low side liquid refrigerant temperature in the cooler coil. To prevent freezing, this low side tempera ture will always be above 32 F. if the beverage freezes at that point.

As long as any liquid refrigerant is present around the bulb, its'influence predominates and the bulb and valve are at out off conditions. This is true even if warm beverage is present near The cylindrical opening 35 with- I the bulb region. But if the refrigerant around the bulbis in gasifled form, its influence on the bulb is negligible in comparison to the beverage liquid. Hence under such conditions, beverage temperature will control the bulb and valve condition.

From the above it is apparent that the location of the bulb with reference to the precise end of the refrigerant conduit is subject to variation to suit requirements. Thus if the bulb is so disposed that an excessive length of refrigerant conduit remains, it will be apparent that the full cooling capacity of the coil is not being utilized. It is the bulb, in the direction of refrigerant flow, aids in cooling 'andpermits remnants of liquid refrigerant particles to gasifyi. e. dries out the gas, nevertheless it is obvious that beyond such a desirable short length, any additional conduit is simply wasted. The major part of the cooling occurs ahead of the bulb; i. e. between the bulb' and the control valve.

I claim:

1. The combination of, tiers of spirally wound tubing having spaces between each turn, vertical side walls surrounding the sides of tubing forming vented channels, means for supplying a remeans controlled by said thermo-responsive element for cutting off the refrigerant supply when said thermo-responsive element is chilled by said,

refrigerant and adapted to cut in said refrigerant supply upon saidthermo-responslve element being warmed by incoming beverage, a gas chamber into which evaporated refrigerant flows from said channels, the pressure being balanced with said channels.

2. In a beverage cooler, the combination of a beverage coil having inlet and outlet openings, disposed within a refrigerant chamber having inlet and outlet openings, means for controlling a flow of liquid refrigerant into said chamber to be depositedon an elevated portion of said coil for downward flow thereon for final disposition in said chamber, a temperature responsive means placed on the upper side of said coil substantially near its inlet end to thermaliy control said controlling means, means for guiding said liquid refrigerant while flowing over said coil as it approaches said: temperature responsive means.

3. The device according to claim 2, wherein said refrigerant guide is spacedfrom side walls of said refrigerant chamber.

.true that some of the refrigerant conduit beyond frigerant to said vented channels at the top 4. A liquid cooler comprising a sealed casing,

'a refrigerant conduit disposed within said casing and spaced therefrom, at least one beverage conduit in intimate thermal relationship with said refrigerant conduit disposed within said casing, I means for supplying liquid refrigerant to said refrigerant conduit and for discharging gasified refrigerant into the space between the casing and refrigerant conduit anda pipe for with- 6. A liquid cooler comprising a sealed casing,

at least one beverage conduit in coiled formation within said casing and spaced therefrom, baffle plates enclosing said conduit to form a liquid refrigerant chamber, said baffle plates being spaced from said casing and at the bottom permitting communication between said refrigerant chamber and the space around said baffles, means for supplying liquid refrigerant near the top of said liquid refrigerant chamber, said liquid. refrigerant being adapted tofiow by gravity over the beverage conduit and down toward the bottom of the casing and gasifying in the course of its travel, and a refrigerant suction pipe disposed within said gas space outside of said baflie near the bottom thereof.

7. A liquid cooler comprising an annular sealed casing, an annular chamber within said casing and spaced therefrom, said chamber having side and top walls but being open at the bottom to provide communication between the free space v within the casing outside of said annular chamber and the space within said annular chamber, at least one beverage conduit disposed within said annular chamber, means for supplying liquefied refrigerant to said annular chamber near the top'thereof, said liquefied refrigerant being adapted to drop by gravity and gasifying in the course of its travel, and a gasified refrigerant suction pipe opening in the space between said casing and the outside of said annular chamber near the bottom of the casing.

8. A liquid cooler comprising a pair of conduits in intimate thermal relationship, one of said conduits being for refrigerant and terminating in a gas chamber and the other for beverage, means for supplying liquid refrigerant to said refrigerant conduit at an elevated point with said refrigerant adapted to drop by gravity through the conduit toward the end thereof, said means including a control valve, means for supplying uncooled beverage to the beverage conduit in proximity to the refrigerant conduit end in counterflow relation to said refrigerant flow,

a thermostatic bulb for controlling said valve, said thermostatic bulb being disposed in the refrigerant conduit at an intermediate point thereof and being in intimate thermal relationship with the beverageconduit, said thermostatic bulb and valve operating between predetermined bulb temperature limits, the higher limit being the liquid refrigerant cut in temperature normally due to uncooled incoming beverage and the lower temperature limit being any temperature at or above the temperature of the liquid refrigerant which may surround the bulb for cutting off. the liquid refrigerant, said bulb being predominantly influenced by liquid refrigerant.

9. A liquid cooler comprising a beverage conduit in coiled formation, plates. enclosing said conduit coils and forming a refrigerant conduit path along the outside of said beverage conduit,

a casing enclosing both conduits, said casing be ing sealed with the refrigerant conduit opening into said casing near the bottom thereof, means for supplying liquid refrigerant to the refrigerant conduit near the top thereof with said refrigerant adapted to fall downwardly by gravity, a gasified refrigerant suction pipe passing through said casing with its opening near the bottom thereof and outside of the refrigerant conduit proper, a valve for controlling the flow of liquid refrigerant, and thermostatic means'including a bulb in the refrigerant conduit against the beverage conduit for controlling the valve, said bulb being adapted to cutoff the refrigerant upon the presence of liquid refrigerant around said bulb and to cut in the refrigerant supply upon the presence of substantially uncooled beverage in the conduit at the point where said bulb is located.

10. A cooling unit comprising a cooling conduit terminating in a gas chamber adapted to be supplied with liquefied refrigerant and so disposed that said refrigerant is fed at the top and drops by gravity to the bottom which communicates with said gas chamber and from whence a gas outlet takes the gasifled refrigerant, said conduit being surrounded by a medium to be cooled, a valve for controlling the refrigerant supply to said conduit, a control for said valve including a thermostatic bulb, said bulb being disposed in the cooling conduit and attached to a wall thereof and being subject to the temperature of the refrigerant within the conduit and the medium to be cooled outside of the conduit, said control operating between predetermined bulb temperature limits with the higher temperature as the liquid refrigerant cut in point determined by the temperature of the uncooled me-, dium and the lower temperature as the cut off point, said lower temperature being at or above the temperature of liquid refrigerant which may surround the bulb, said bulb being predominantly influenced by the liquid refrigerant.

11. In a beverage cooler, the combination of a refrigerant chamber having an inlet and an outlet, coils of spirally wound tubing disposed within said chamber and having inlet and outlet openings, side walls spaced from said chamber walls for said tubing forming a refrigerant channel having a downward slope, means for supplying liquid refrigerant to said channel for downward flow, said channel terminating at the bottom and conducting refrigerant into said chamber proper, a temperature responsive bulb in said refrigerant channel, and means controlled by said bulb temperature for cutting off the liquid refrigerant supply to said chamber when said bulb temperature reaches a predetermined value and for cutting in said liquid refrigerant supply when said bulb temperature reaches a predetermined higher value.

12. The cooler of claim 5 wherein said beverage flow is counter to the liquid refrigerant flow and wherein a temperature responsive bulb is disposed in the refrigerant conduit to be affected by both refrigerant and beverage temperatures,

ANTHONY T. STOCK.

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