US2594502A - Liquid cooler and evaporator coil therefor - Google Patents

Description

April 29, 1952 J. SAHS LIQUID COOLER AND EVAPORATOR COIL THEREFOR 2 SHEETS-SHEET 1 Filed May 25, 1949 Zmvent r LeonardJS April 29, 1952 s s 2,594,502

LIQUID COOLER AND EVAPORATOR COIL THEREFOR Filed. May 25, 1949 2 SHEETS-SHEET 2 3nventor o 3 4 Leonardl 50125, flaw/67W Gttomeg Patented Apr. 29, 1952 LIQUID COOLER AND EVAPORATOR COIL THEREFOR Leonard J. Sahs, Hamburg, N. Y., assignor to Fedders-Quigan Corporation, Buffalo,,N. Y.

Application May 23, 1949, Serial No. 94,868 sclaimsq (01. 62-441) This invention relates to liquid or beverage cool'ersyand it hasrparticular-reference to the" provision of an improved combined refrigerant and liquid coil assembly which is especially applicable to refrigerated beverage coolers oi the draft or pressure supplied type.

One typical application of the pressure type cooler is in oflice and factory'buildings, in which the municipal water supply is connected to the cooling equipment to provide for the needs and comfort of the occupants. A related application which may be mentioned is in equipment for cooling carbonated beverages, inwhich the liquid is supplied under pressure from' a local reservoir. In devices of this nature, the demand, or number of cooled drinksto be dispensed per hour, is a highly variable quantity, ranging from substantially nothing during the hours when the premises are unoccupiedito high demand or peak loads during certain periods of occupancy, when a more than average number of-individuals seek the facilitiesof the cooler in rapidsuccession. This variation in demand has led in recent years to the general adoption of storage reservoirs, in which. the liquid is retained either" after having been cooled, or in which it may also be subjected to further cooling.

Storage tanks are,.however, open to several objections, one of which of course. is the additional cost. Again, it is required under various sanitaryeodes that the tanks must be periodically cleaned, or at least so constructed as to be susceptible of cleaning, which presents-problems of access thatare augmented by thenece'ssity of theirv being liquid tight under the pressures to be encountered. Again, it has'been found, particularly with water coolers, that storage. tanks simple flushing or backwashing operation and without extended dismantling; and wherein the arrangement 'is such as to safeguard the apparatus from freezing and bursting during off-load periods. The coils may be made in various sizes.

to meet installation specifications for a givenquantity'of beverage to be dispensedduring peak loads, and within prescribed temperature limits,

and they may bereadily installed in complete or unitary refrigerated dispensers to meet the:various conditions encountered. in practical use. Various other features and advantages ofthe invention will become-apparent as this description proceeds.

The invention will be fully-understood'irom the following detailed description of a preferred embodiment thereof, illustrated'in the accompanying drawing, wherein:

Fig. 1 is a view, partially in elevationand partially in section, of a pressure typewater cooler;

Fig. 2 is an enlarged topplan of the-coolerwith the cover plateremoved;

Fig. 3 is an enlarged section onithe line 3--3 of Fig. 2, andtaken adjacent'the discharge end of the water and refrigerant coils;

Figs. 4 and 5 are sections taken onthecorrespondingly numbered lines in Fig. 3;

Fig. 6 is a section taken substantially onthe line 66 of Fig. 2, andadjacent the inlet end of' the water'coil; and,

Fig. 7 is a fragmentary perspective of the inner end ofthe control instrument bulb well.

The invention is shown as incorporated in a drinking fountain orwater cooler including a. sheet metal upright casing I! provided with a removable top cover I2. A horizontal wall I3 and a vertical transverse wall [4 within the easing define a compartment 15 within which the liquid is cooled, and they separate thecooling elements-from a lower machinery compartment Hi. 'It' will be noted thatithe transverse-wall H isspaced from its parallel outer wall I] of the cabinet, to provide a duct 18 for communication between the compartments l5 and I6. Inasmuch as the remaining details of the cabinetconstruc tion are not material to an understanding of the present invention, they will not be further described.

The lower compartment l3l r'eceives a refrigerant compressor' I3, herein shown as Ofx'th8"h61'- metic type, whose discharge outlet is connected by a tube 2! to an air-cooled condenser 22, con-- venientl'y mounted in" a recess formed in one of the cabinet wallsbelow the cooling compartment [5. A motor driven fan 23, suspended from the horizontal wall l3,:provldes for. circulation of air through the machinery compartment and the condenser, to remove .heat. of compression in the usual manner. Theoutlet side of the condenser 22 is connected to astrainer anddrier 24, from which the condensed refrigerant flows into. a

supply line 25, which may be of the capillary tube or restrictor type, and which extends upwardly through the duct I8.

The refrigerant evaporator is in the form of a double helical coil, whose convolutions are spaced from each other, but are in contact with an internested single helical coil which constitutes the liquid supply passage and storage reservoir. The liquid coil, generally designated by the reference numeral 3|, is formed from a length of tubing whose lower end 32 is connected to a supply line 33 of less diameter, in a manner best shown in Fig. 6. The line 33, which may be half the diameter of the tubing 3|, is telescoped within the end 32 with a tangential contact, and the tube end is then pinched or contricted around the line 33 to form joining lips 34 which engage each other. The connection is thereafter sealed with hard solder or brazing compound to form a pressure resistant liquid-tight joint. The free end of the line 33 extends to one of the compartment walls, where it is connected to a nipple 35, which in turn is connected to the municipal water supply pipes at the time of installation.

It is to be noted thatthe line 33 is placed on the bottom or lower trace of the tube end 32, so as to eliminate a trap or pocket in which water might be retained when the cooler is disconnected.

The coil 3|, from the lower end 32, is Wound with a number of superimposed spaced ascending convolutions 36, through which the liquid flows in counterclockwise fashion as viewed in Figs. 1 and 2. The final upper turn 31, rather than being wound on a cylindrical form, is given a generally U-shape or return bend formation which terminates in an upper or outlet end 38. This formation somewhat increases the length of the coil without appreciably adding to the height of the helix, and it provides a more flexible terminal portion which facilitates assembly with the other components of the cooler. The end 38, like the inlet end 32, is fitted with a length of tubing 39 of less diameter, which is sealed in similar fashion, but with a difference which will presently be described. The tube 39 is also bent upwardly to extend to the cover I2 where it is connected in any conventional or desired manner to a faucet 4|, herein shown as being of the finger controlled bubbler type.

The refrigerant expansion coil consists of a continuous length of tubing, of less diameter than the water coil, and its disposition and formation may be traced from the discharge end of the capillary tube 25; An adapter 43 serves to connect the end of the tube 25 to the inlet end 44 of the evaporator coil, as is best shown in Fig. 2. The coil extends from the inlet end 45 in a loop 45 which passes to the under side of the return bend formation 31 of the liquid coil 3|,arid thence follows on downwardly in clockwise manner through a series of convolutions 46 which are in bonded contact with the under side of the water coil convolutions. Having arrived at a point adjacent the inlet end 32 of the coil 3 the refrigerant tubing is given an upward turn into a riser section 41 extending to the top of the water coil. A return bend 48 directs the refrigerant tubing into engagement with the upper side of the coil 3|, where it is bent into a series of convolutions 49, also directed in clockwise manner in contact with the coil 3|.

When the refrigerant tubing again approaches the inlet end 32 of the liquid coil 3|, it is once more bent into a riser section 5| extending to the top of the transverse wall I 4, where it is connected to a suction line 52 extending through the duct Hi to the inlet of the compressor !9. As shown in the various figures, the convolutions of water and refrigerant coils are respectively spaced from each other, but the turns of the refrigerant coil contact the turns of the water coil on opposite sides, and they are advantageously soldered or otherwise bonded throughout the extent of contact. With this arrangement, there is substantial countercurrent flow between the liquid and the refrigerant, and the separation of the several convolutions avoids a condition of short-circuiting which would interfere with maximum heat transfer and rapid cooling of the liquid.

The integrated coils are mounted on the floor or horizontal wall l3 of the low-side compartment IS in any suitable manner, as by means of spaced brackets 53. The spaces around the coil and the several convolutions are packed after assembly with a suitable insulating material. which has not been illustrated for purposes of clarity. In this connection, .it will be noted that the circuit connections between the high and low sides of the refrigeration system extend through the duct l8, rather than directly through the wall I3. This notonly facilitates assembly and servicing, but it also eliminates a tendency for cooling the Wall |3 to the dew point, with attendant condensation of moisture or sweating. Waste water from the bubbler 4| vfiows into a depressed portion of the cover H. for disposal through a screened drain pipe which is formed with an angular section 58 extending to a cabinet wall and a nipple 57, which is connected to the sewer in the usual manner. In order further to enhance the efiiciency, the capillary tube 25 and the suction line 52 may be soldered to each other between the high and low sides to provide a drier section, as has heretofore been proposed in the art.

It will be recalled that the liquid inlet. and outlet lines 33 and 39, connected to the ends 32 and 38 of the coil 3|, are of less diameter, and are positioned in engagement with the bottom side of the coil 3|. This construction has several advantages. When the cooler is disconnected from the mains, the liquid contained therein can readily drain and hence the cooler can be shipped or stored in a dry condition, and with out danger of freezing of trapped water. Again, the increased cross sectional area of the coil 3| imparts an increased capacity, through which the liquid flows with a diminished velocity, thereby providing an additional time factor for cooling the water, even though the cooler is subjected to a peak load. The construction also coordinates the control of the refrigerating cycle in a manner well adapted to reduce the water temperature to a desired value, and withal avoid the freezing of the liquid in the coil 3|.

Heretofore, considerable difliculty has been experienced, particularly with helical type coils, in regulating the relations between the refrigerant and water circuits, in such manner as to provide both satisfactory cooling and insurance against overcooling during low demand intervals. Reierring primarily to Figs. 2, 3, and 5, it will be noted that the end 38 of the coil 3| is pinched around the outlet tube 39, in like manner to the inlet connection, and it is also pinched around a smaller tube 6| which extends several inches into the water coil 3|. The joint is crimped and soldered as has previously been explained. The tube 6| is formed at its innermost end with a pinched and soldered portion 62, to which is connected a flat plate having a length substantially equal to the internal diameter of the coil 3|. Theplate 63 therefore serves as a support and spacer for the tube 6|, maintaining it at substantially the axis of the coil 3 l, and preventing direct contact with the coil wall. The tubing 6| is therefore immersed in and surrounded by the liquid, which forms a thermal barrier between thetube BI and the refrigerant in the convolutions of the refrigerant coil.

The tubing BI is utilized as a casing or well for the power element of .a. thermostatic control 64 for the compressor l9. Inasmuch as these cold controlsare well known, and the details thereof form no part of the present invention, a brief explanation will suffice. The compressor 19 and condenser 22 cooperate to supply compressed refrigerant, from which some of the heat of compression'has been extracted, to the low side or evaporator coils. The refrigerant here expands, with absorption of heat and reduction of the water temperature. Electric current is supplied to the compressor l9 through a service line 65 extending through a junction box 66 and a line 61 to the control element 64. This element includes an electrical switch which is automatically operated by the fluctuations in the pressure of refrigerant contained in a small closed tube 68, which constitutes the power element or control bulb from the element 64. When the switch contained in the element 64 is closed, current is supplied to the compressor 19 through the cable 69.

The pressure and temperature of the refriger- :2

ant are directly related, and therefore an increase in temperature of the water surrounding the well 6| will increase the pressure of the refrigerant in the tube 68, to close the switch, supply current to the compressor, and thereby institute a cycle causing rapid expansion of the refrigerant in the evaporator, with concomitant cooling of the liquid in the coil 3|. When the cuit may be many degrees below the freezing 6 point of water, and hence, if the bulb member 68 were in direct contact with th evaporator coil, it could become so chilled that the liquid in the coil 3| could also be cooled below the freezing point, resulting in the bursting of the liquid coil and attendant damage. Accordingly, the control bulb 68 is insulated from the working refrigerant circuit by an envelope of water, as is clearly shown in Figs. 3 and 4.

A condition may, of course, arise to cause the formation of a thin, and therefore harmless, film of ice on the inner wall of I the coil 3|. The growth of any such adventitious ice film is safeguarded against in two ways. First, the bulb well BI is located on the discharge end of the coil 3!, or at the region where the water has been subjected to the maximum refrigerating effect, and is therefore at its lowest temperature. Again, it is well known that for satisfactory operation, the water does not have to be at an extremely low temperature. On the contrary, ice waterfis too cold' to provide a generally satisfactory potable beverage. A more satisfactory temperature range is from about ten to twenty degrees above the freezing point. Therefore, the control elemerit-64 is so adjusted (forthe case of aowater adjustment knob.

Under the conditions selected as an illustrative example, it willbe seen'that the water directly in contact with the bulb well 6| cannot reach a temperature much, below 40 F.-the tolerance from the 43 F. value being employed to compensate for irreducible variations in the operation of the element 64 itself. Hence, at the coldest part of the coil 3|, there is a body of'liquid several de-'- grees above the freezing point,which is always i available to melt any film of ice whichmight be 1 formed. Likewise, as the temperature of the water at this point cannot greatly exceed 50 F.,

without instituting operation of the compressor, the water being dispensed will, under all loads and demands within rated capacity, be cooled to a temperature which is satisfactory for drinking purposes. It will be readily understood that the numerical example just given is for illustrative purposes, and is subject to modifications depending upon the nature of the liquid being dispensed, and the tastes and desires of those using the cooler.

It will accordingly be seen that the invention provides improved apparatus and equipment, applicable to a variety of liquid cooling problems, and which is fully adapted to perform its intended purposes. While the invention has been described in detail with respect to a single embodiment thereof, it will, of course, be understood that it is susceptible of numerous modifications and variations without departure from its principles or its scope as encompassed by the following claims.

I claim:

1. A liquid cooling coil comprising a helix formed of tubing wound into a series of convolutions, inlet and outlet lines of less diameter than said tubing sealed into the ends of the helix, a second tube of less diameter than the helix tubing sealed into the outlet end thereof, said second tube having an internal diameter suficient to provide a bulb well for the power element of a refrigerant control device, said second tube having a sealed inner end, a spacer member disposed between the second tube and the internal Wall of the helix tubing to position the second tube adjacent the axis of the helix tubing and enable liquid to flow around the entire surface of the said second tube, and a refrigerant coil bonded to the external surface of the helix tubing and disposed at substantially diametrical regions thereof along the convolutions, said refrigerant coil having portions overlying at least a portion of said second tube, the convolutions of the helix being spaced.

2. In a refrigerated liquid cooler of the type having means for cyclically supplying volatile refrigerant to an evaporator in responsev to changes in temperature, a helix formed of tubing wound into a series of spaced convolutions, a liquid inlet line of less diameter than the helix tubing sealed into one end thereof, an outlet line of less diameter than the helix tubing sealed into the other end thereof, a small tube sealed into the outlet end of the helix tubing and extending therewithin in spaced relation to the internal wall thereof, the inner end of the small tube being sealed, a refrigerant expansion coil having an inlet 'end connected to said supplying means and disposed along the convolutions of the helix tubing to extract heat from the interior thereof, said helix and expansion coil being insulated from said supplying means and the surrounding air, the outlet end of the expansion coil being connected to said supplying means to provide for cyclic flow of refrigerant, a pressure responsive control device for governing the operation of said supplying means, and a control element for said device comprising a refrigerant containing tube positioned in said small tube.

3. A liquid cooling coil adapted to be incorporated in a refrigeration system comprising a helix formed of tubing wound into a series of spaced convolutions having terminal inlet and outlet ends, the inlet end extending substantially radially .from the longitudinal axis of the helix, an inlet line of less diameter than the helix tubing sealed into the inlet end and disposed tangentially to the lower portion thereof, an outlet line sealed into the outlet end of the helix tangentially to the wall thereof, a second tube of less diameter than the outlet line also sealed in the outlet end of the helix tubing and in spaced relation'to the Wall thereof, said second tube having a sealed inner end and being of such diameter as to receive the power element of a thermal control element for the refrigeration system, and a refrigerant expansion coil formed of tubing of less diameter than the helix tubing bonded to the external surface of the helix tubing through substantially the entire length thereof between said terminal ends.

LEONARD J. SAHS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Lyons Feb. 22, 1938 Billings Aug. 30, 1938 Wyllie Jan. 11, 1944 Number

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