US2508289A - Liquid cooling unit - Google Patents

Description

May 16, 1950 F. G. PECK LIQUID COOLING UNIT Filed March 30, 1949 F l G FRED- s. PECK,

Patented May 16,, 1950 UN I N '1" OFF l-CE LIQUID ICOOISING UNIT "Fretl GLPeck, Hag-'crstowmMii.

Application March 30, 1949 ,Serial No. 84,317

1 invention relates to improvements in cooling units, and more particularly to an improved immersion or drop-in cooling unit designed especially Ltor can-type milk coolers,but

suitable of other uses requiring eflicient cooling of-aliquid ina tank or container.

,Drop-in cooling units are well known but, as previously constructed, have the disadvantage of excessive weight and insome designs unbalanced distribution of weight. Such results not only in difficulties in packing, shipping and removing the .unit from the cooler cabinet for servicing,

-etc.,-but has alsogiven rise to the practice of the unit'being-dragged across 'theiifioor andbecoming contaminated and thereby contaminating the liquid in which the unit is immersed.

Stated broadly, the present invention contemplates and aims to provide an improved selfcontained package type cooling unit which is characterized bylightness in weight as compared to prior units, so thatit may readily be handledin shipment and use, and which moreover may be readily removed from the cooler cabinet and delivered to aservice center in a compact shipping container. 7

Another-object of the-invention is the provision of; a drop-in cooling unit-of improved design, according to which the unit comprises .a vertical stack-up of component ,parts, with the weight of the heavier components, i. e. sealed-compressor unit, agitator and .fan motor and condenser, centered on the axis of the unit and in .a relatively small space which for a standard unit is approximately 1 3" ,x :14

Still another aimof the invention .is the provision of a drop-in cooling unit as aforesaid, which is characterized, as compared to prior units serving similarfunctiomby-a reduction in the numberof parts,'by alowerpower consumption, and by increased efiiciency.

Another object of theinveritionis the provision of a drop-in cooling unit employing a sleevetype evaporator of compact, economical con-- struction giving a high heat transfer surface, and which is readily cleanable, the "latter being important in maintaining sanitation standards. A still further object of the invention is the hprovision of a drop-in cooling unit as last above characterized, wherein the evaporator is supported solely 'by tubular structural members which also "function as refrigerant passages, thereby introducing economies in construction, and moreover "allowing the maintenance "of an fe'fiic'ierit head of refrigerant 'in .the evaporator evaporator. This arrangement is also or "advantage 'in tha't the "tubular structural member providing the suction riser, by proper"selection "(If si2e,'furnis'hesfa convenient separatlon'c'ha-mher for entrained liquid not boiled mi in the evaporator, "allowing it to "fall "back into "the "'boiler, with the result thatthesuction riser acts as a surge chamber. The construction wherein tubular structural members providethe refrigerant passages for "theevaporator also as 'sists in maintaining smooth, readily 'c'ieanable surfaces.

The above and other objects and advantages of the improved drop-in cooling unit will be seen from the following description thereof, takenwiththe accompanying drawing, in which Fi g. 1 is a part-sectional elevational view i1- "lustrating theimpr'oved drop-in 'cooling'unit of 'theinvention; and

Fig.2 is a sectional view of a can-type cooler illustrating the'manner of use of acooling unit as shown-in Fig. 1.

The illustrated drop-in cooler is intended for use .in cooling watereontained in the tank of a can type milk "cooler, thus in turn to cool,milk in-cans whichare immersed in the cooled water. A typical cooler ll! is illustrated liniFig. '2 and comprises an insulated cabinet housing a water tank Ill whichiaiin useAilled .tothedesiredilevl. ,The cabinet .top may include .a i'fixed section 12 andahinged cover 13, the lfixed section supporting the cooling unit as shown, andiorthis purpose being provided with ,alholecl'lilthrough which the evaporator may'beflowerefd into the waterin the tank. The hinged cover section 13 provides flrfor convenient access .to the interior of the cabinet as required inlowering the milk cansinto the cabinet and lifting them therefrom.

As seen in Fig. ,1, the improved cooling tunit employs a horizontal supporting plate or deck member F6 adapted 'to .be mouritedlon the flfixed section I 2 ,of 'the cabinet top. In a standard cooling unit -built in accordance with 'theprin- .ciples of the invention, "the supporting deck is rectangular and its dimensions are 13" .x 1'14". Supported from and spaced above the 'deck by inverted LU-s'haped 'bnadkets 11, 11a is ,a sealed motor-compressor unit "1113 which is vertically arranged. In the space between said unit and the deck member is mounted a motor 119 also vertically arranged and with itsaxisin alignment with that (of the motor-compressor unit. The deckmeniber It also supports a two-section .condenser, "th'esetions of which, ,designate'd'fifl, 20a, are connected in circuitby asuitable connection sleeve 21 along their longitudinal edges.

(not shown) and are disposed symmetrically to the sides of the axis of the motor I9. A single section condenser disposed to encircle the motor I9 may be substituted for the two-section condenser as described.

The head shaft of the motor [9 drives a fan 22 which, it will be observed, operates in a plane somewhat above the upper line of the condenser and below the motor compressor unit. The space between the U-shaped brackets [1, Ha is closed, front and rear, by bridging plates, of which the front plate 23 is shown. Accordingly, when the fan 22 is placed in operation, it draws in air through the condenser sections, thereby cooling them, and also direct air upwardly against and about the motor-compressor unit, thereby cooling the latter also.

Supported from below the deck I6 is an evaporator generally designated 25 adapted to be immersed in the liquid of the tank, thereby to cool the same. As shown, the evaporator comprises interfitting inner and outer sleeves 26, 27, the inner sleeve having a helical groove formed therein as by rolling, which terminates near the ends of the sleeve. The outer sleeve 21 is of plain, cylindrical form and when assembled with the inner sleeve forms therewith a helical refrigerant passage designated 28. The inlet to said passage is provided by an opening 29 formed in the outer sleeve adjacent its lower edge, and the outlet from said passage is formed by an outer sleeve opening 39 provided adjacent its upper end.

The evaporator 25 is supported from the deck It by two vertically disposed structural members 32, 33, and it is a feature of the invention that said structural supporting members are formed tubular so that, in addition to their supporting function, they also provide refrigerant passages for the evaporator.

The lower ends of the structural members 32, 33 extend the full axial length of the evaporator and for said length are formed with half-round section, being welded to the evaporator outer By this arrangement, the evaporator is rigidly aifixed to the structural members and, by virtue of the fact that their half-round lower ends of the semicircular contour merge nicely into the curvature of the outer sleeve 28, no crevices are formed in the joint between structural members and evaporator, with the result that the joint may be readily cleaned.

In the construction illustrated, one tubular structural member 32 connects to the low level inlet 29 to the helical refrigerant passage of the evaporator, and the other structural member 32 communicates with the high level or outlet opening 30 of the aforesaid passage. At its upper end, the structural supporting member 32 connects through a suitable union with the low tem-- perature side of the expansion valve 35, and the upper end of the other structural member 33 connects through a suitable union with a tube 36 connected to the suction side of the compressor.

The expansion valve 35 is connected to the liquid discharge side of the condenser section 20a through a receiver 3'! and liquid line 31a. Preferably, the tube 36 is disposed in heat-exchange relation with liquid line 31a but is not so shown. It will be understood that the high pressure or discharge side of the compressor is connected by tube 38 with the condenser section 20.

- Conventional controls are provided, such as a standard start-and-stop switch control 40 for the sealed motor-compressor unit, with a bulbtype element 4| carried within the evaporator to extend into the liquid of the tank and connected by a capillary 42 to the switch control, and a thermostatic bulb 43 connected by a. capillary 44 to the thermostatic expansion valve. The capillaries 42, 43 are preferably clipped to the tubular structural members 32, 33, as shown, and, being disposed on the inner peripheries thereof, are protected against damage.

To effect circulation of the liquid in the tank, an impeller 46 is provided, being housed within the tubular or sleeve-form evaporator and disposed near the lower end thereof. The impeller is driven by a vertical shaft 41 journaled for rotation in a lower bearing 48 mounted in a, spider afiixed to the upper edge of the evaporator, and being drivingly connected with the tail shaft of motor H) by a suitable coupling.

It will be observed that the evaporator 25 is disposed on the common axis of motor-compressor unit l8 and motor :9, and that the axis of the impeller shaft all coincides with said common axis. Accordingly, the unit is characterized by a vertical stackup of component parts, with weight centered substantially in the small space represented by the dimensions of the deck memher [6. This arrangement has numerous practical advantages in packaging and shipment Moreover, it permits the unit to be readily lifted from the cooler and delivered to a service center in a compact shipping container. Due to its lightweight construction, taken with the feature of balanced distribution of weight, a cooling unit as aforesaid can be readily handled without the necessity of dragging it across a floor, for example.

As compared to prior cooling units employing a separate motor for driving the agitator or impeller, the use of a single motor for driving both the cooling fan and impeller introduces economy in construction, reduced power consumption, overall increased efliciency, and increased simplicity in maintenance.

Due to the construction of the evaporator 25, additional reduction in initial cost is obtained. Consequent to such construction, the evaporator will maintain a high external pressure, i. e. pressure within the helical refrigerant passage, without collapse or rupture. The use of a helical refrigerant passage provided by a helical groove in the inner sleeve making up the evaporator has the advantage of increased heat transfer area. Moreover, due to the high velocities of the liquid-vapor mixture, oils present in the refrigerant circuit are constantly swept along this passage without undue concentration and returned to the compressor crank case. This absence of a heavy oil film or oil pocket on the heat transfer surfaces results in high heat transfer. The helical convolutions also furnish an irregular although smooth surface on the water side which induces a high degree of scrubbing action, thereby eflectively increasing the film coefiicient of heat transfer, reducing the film resistance on the water side. It will be noted that this high heat transfer on the water side does not present crevices which are likely to be fouled up by foreign matter accumulating in the tank liquid. In case of a deposit on the heat transfer surface, such may readily be cleaned, so that adequate sanitation standards are maintained.

The utilization of the tubular supporting members as refrigerant passages as herein provided not only involves an economy but also allows the maintenance of an efficient head of refrigerant on the evaporator proper, thus maintaining a fully flooded evaporator. By proper selection of size of the tubular supporting member functioning as the suction riser (member 33), the latter may form a convenient separation chamber for entrained liquid not boiled off in the evaporator, allowing it to fall back into the boiler. In other words, the suction riser functions as a "surge chamber. The construction wherein tubular structural members are combined with refrigerant passages also assists in maintaining smooth, readily cleanable surfaces.

As many changes could be made in carrying out the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A cooling unit for a tank cooler comprisin in combination, a supporting plate adapted to be mounted on the top of the'cooler cabinet, a sealed motor-compressor unit and a motor mounted on said plate, both said motor-compressor unit and said motor being vertically arranged and disposed on a common axis, a condenser also mounted on said plate with its weight distributed to opposite sides of said axis, a fan driven by said motor for cooling the condenser and motor-compressor unit, an open-ended evaporator depending from said plate to extend into the liquid contained in the tank, an impeller for agitating said liquid, and a shaft extending between motor and impeller for driving the latter from the motor, said evaporator, agitator and shaft being also disposed on said common axis.

2. A cooling unit as set forth in claim 1, wherein the sealed motor-compressor unit is disposed above the fan and impeller motor, and the fan is disposed intermediate said unit and said motor.

3. A cooling unit as set forth in claim 1, Wherein the condenser is made in two sections which are disposed symmetrically to the sides of the fan and impeller motor.

5. A cooling unit as set forth in claim 1, wherein the sealed motor-compressor unit is disposed above the motor, the condenser is made in two sections which are disposed symmetrically to the sides of the motor, and the fan is disposed intermediate said unit and said motor, thereby to draw in air through the condenser sections and to direct cooling air on to said unit.

6. A cooling unit for a tank cooler comprising, in combination, a supporting plate adapted to be mounted on the top of the cooler, a refrigeration system mounted from said plate including a sealed compressor unit and a condenser disposed above the plate, a sleeve-type evaporator disposed below the plate to extend into the liquid contained in the tank, said evaporator comprising interfitting inner and outer sleeves, the inner sleeve having a helical groove terminating adjacent the ends thereof and providing a helical refrigerant passage, the outer sleeve having an opening adjacent its lower end providing an inlet to the refrigerant passage and an opening adjacent its upper end providing an outlet from said passage, and tubular structural members supporting the evaporator from the plate and. providing refrigerant passages, said members extending substantially the full length of the evaporator and having half-round section for said length and being each connected along both longitudinal edges to the outer sleeve, one of said tubular structural members communicating with the inlet to the helical refrigerant passage, and the other tubular structural member communicating with the outlet from said passage.

FRED G. PECK.

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

UNITED STATES PATENTS Number Name Date 939,021 Hendrix Nov. 2, 1909 1,992,988 Blahnik Mar. 5, 1935 2,050,192 Melcher Aug. 4, 1936 2,188,839 Markley Jan. 30, 1940 2,203,439 Oliver June 4, 1940 2,455,162 Donnelly Nov. 30, 1948

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