US2748574A - Water defrost refrigerated showcase - Google Patents

Description

June 5, 1956 D. H. GASTON WATER DEFROST REFRIGERATED SHOWCASE 3 Sheets-Sheet 1 Filed March 24, 1952 .N 5 km H mm M mfifim N. 7 I y 4 m Mv MfiM 2 Z June 5, 1956 D. H. GASTON 2,748,574

WATER DEFROST REFRIGERATED SHQWCASE Filed March 24, 1952 5 Sheets-Sheet 2 flo/vALz) h. GA STON BY fir 6 8 H T7012 NEY$ June 5, 1956 D. H. GASTON WATER DEFROST REFRIGERATED SHOWCASE -melting'the frost accumulated thereon.

United States Patent WATER DEFROST REFRIGERATED SHOWCASE Donald H. Gaston, Los Angeles, Calif., assignor to Weber Showcase & Fixture Co., Inc., Los Angeles, cans, a corporation of California Application March 24, 1952, Serial No. 278,246

Claims. (Cl. 62-895) This invention relates to an improved water defrost refrigerated showcase.

It is an object of this invention to provide means-for periodically defrosting an open type refrigerated showcase.

It is a further object of this invention to provide water defrost means for a refrigerated showcase which is unaffected by varying water pressures in the supply lines.

Still a further object of this invention is to provide water defrost means for a refrigerated showcase wherein the volume of water utilized is readily controllable.

Still a further object of this invention is to provide means for defrosting a refrigerated showcase which'insures a continuous supply of water to the defrosting device during a predetermined period of time.

Other objects and advantages of this invention will be readily apparent from the following description.

Inthe drawings:

Figure 1 is a perspective view with the showcase'in phantom of a showcase embodying this invention;

Figure 2 is a side elevation partially in section, taken on line 2-2 of Fig. 1, of a showcase embodying this invention.

Figure 3 is a rear elevation partially in section, taken on line 33 Fig. 2, of a showcase embodying this invention'.

Figure 4 is a schematic representation of an electric circuit useful in performing certain features of the present invention.

Figure 4A is a simplified version of the circuit .illustrated in Figure 4.

Figure 43 illustrates the relative times at which the switches shown in Figures 4 and 4A are operated;

Referring now to Figures 1, 2 and 3, an open-type refrigerated showcase is illustrated having side walls Hand 14, a high rear wall 16, a low frontwall 18, and a-base 20, all of which are insulated and constructed in the usual-manner. Provided in the display caseis an open display bin 22 which extends from side wall to side wall-but terminates short of the front and rear wallsito form air passages 24 and 26. Blowers 28 are located beneath the display bin adjacent the refrigerating coils 30 so that air is directed over the coils 30 and circulated through either one of the air passages over the top of thezopen display bin and through theother air passage and isrecirculated in a manner well known to those skilled in the-art. As cooled refrigerant is circulated through coils 30 considerable moisture condenses on thecoils necessitating defrosting of the coils. This is accomplished by water from tank 32 being released through pipe'34 "to the pipe 36'which is provided with a plurality of spaced orifices 38 which sprays the water evenly over the coils The water and frost .drop onto the inclined base 20 between the coil support brackets 40 and 42 and out drain 44 which is .positioned at approximately the lowest point in the base 20 which base may be formed to drain all the water to a low point as best seen in Figure 3.

Water flow from. the tank 32 to pipe 34 is controlled by rubber ball valve46 which seats in a valve seat 48 formed in the upper extremity of pipe 34. When the ball valve 46 is raised by means of solenoid 50 water passes from the tank 32 through pipe 34 out orifices 38 and over coils 30 and out drain 44 defrosting the coils. When the solenoid 50 is tie-energized the .ball 46. again seats on seat 48 terminating flow to the coils.

It is of course desirable to terminate circulation of refrigerant through coils 30 and shut off blowers 28 during this defrost period.

Water is admitted from any suitable source through pipe 52 to a float valve 54 which valve is controlled by the position of ball 56. When the ball is lowered it forces spring urgedplunger-58 down opening the float valve. When water fills the tank the ball rises and a spring closes the float valve and urgesplunger 58 upwardly.

If for some reason the float valve fails to function properly an overflow tube 60 may be provided which terminates above the normal level of water in the tank and at the other extremity in the pipe 34 below the ball valve 46.

As previouslydescribed, when defrost commences the compressor motor circulating refrigerant is stopped, the blowers are shut off and the solenoid 50 is energized. This may be accomplished by thecircuit illustrated in Figure 4, which circuit may behoused in the control box 51.

The circuit is energized by an alternating current source which has opposite terminals thereof connected to the leads 101, 102. A clock 103 has its terminals connected to such leads 101, 102,- and is constructed in conventional manner to operate the associated normally open switch 103A andto maintain such switch 103A closed for a predetermined time, for example, for 5 minutes. The exact time at which the switch 103A is closed may be adjusted, and since commercially available clocks are well known for this purpose, a detailed description of a particular one is not given here.

Closure of the switch103A results in energization of the relay winding 105 to close the normally open switch 105A and to simultaneously open the normally closed switch 105B. Closure of switch 105A results in energization of the cam motor 106 to cause rotation of its shaft. The cam motor 106 serves to operate the associated switches106A, 106B and 1060. For this purpose, the cam motor 106. has a cam (not shown) mounted on its output shaft for operating such switches 106A, 106B and 106C in the time intervals discussed below and illustrated in connection with Figure 413. After the cam motor 106 has been energized fora relatively short period of time, its associated normally open switch 106A is closed to thereby seal the relay winding 105 to assure the continued energization vo-f relay winding 105 even though the switch 103A is allowed to subsequently assume its normally open position. Asamatter of fact, the switch 103A, after a short period of time, .as illustrated in Figure 4B, is allowed to open.

Figure 4B shows a series .of hatched rectangles, each hatched rectangle servingto illustrate the time interval during which the associated switch is actuated from its normal condition. Thus, at time To, the clock switch 103A is actuated to closed position. Subsequently, at time T1, the cam operated switches 106A, 106B and 106C are simultaneously actuated. Thereafter, at time T2, the switch 103A is allowed to open but, of course, since the switch 106 is closed, relay winding 105 continues to be energized.

Energization of relay winding 105, in addition to causing closure of switch 105A results in opening of the associated relay switch 105B to thereby de-energize the fan motor 107. The fan motor 107 remains de-energized during the entire defrost cycle. Similarly, the cam motor 106 is energized during the entire defrost cycle; and, the cam motor serves to de-energize itself since after the defrost cycle, the switch 106A is allowed to open to thereby cause de-energization of relay winding 105 and opening of the relay switch 105A. The normally closed cam operated switch 1063 is serially connected with the compressor control circuit 108 so that while such switch 106B normally allows such compressor control circuit to be energized, such control circuit 108 is de-energized a fractional part of the defrost cycle, as represented by the time interval T1T4. The other cam operated switch 106C, although actuated at the same time as the other switches 106A and 106B, remains actuated for a shorter period of time than switch 106B. In other words, the switch 106C is actuated only during the time interval represented by the time interval T1T3. The switch 106C, a normally open switch, serves to energize the water control solenoid 50 so that water flows during the time interval T1-T3. During the time interval T3T4, the water is allowed to drain; and after time T4, the compressor is fully energized so that it operates during a later fractional part of the defrost cycle, during the time interval T4-T5.

By these expedients, the compressor is shut otf during the period that water is introduced into the case and also during the following water drain period; and the compressor is allowed to start up and cool the coil prior to ending the defrost cycle and prior to turning the fans back on.

If desired, the draining line 44 is provided with a normally open solenoid operated valve 110, as shown in Figure 2. When used, the solenoid valve 110 is connected electrically, as designated in Figure 4A, with opposite terminals thereof connected to opposite terminals of the Water inlet solenoid 50; thereby both solenoids 50 and 110 are energized simultaneously and de-energized simultaneously. By this expedient, instead of allowing approximately 40 gallons of water to go through the system and flush out into the drain the solenoid operated valve 110 shuts off the flow of water through the drain, thereby allowing the pan of the case to fill with water, thereby holding the heat of the water and using it. In such case instead of requiring 40 gallons of water for defrost purposes, this amount may be reduced to 20 gallons.

It is preferred that the pipe 34 running from the flush tank to the pipe 36 project down the rear of the case and beneath the case and upwardly through the front wall to the pipe 36. This is desirable to avoid water accumur lating in the pipe and freezing therein during normal operations of the showcase. When the pipe is conducted in this manner any water which may collect outside and below the display case will not be subject to suflicient reduced temperature to freeze the Water. It is sometimes desirable to provide a bleeder tube 62 connecting with pipe 34 prior to its entry at the front of the showcase. Thus any water which accumulates in the pipe 34 above the level of the bleeder tube drains into a suitable receptacle.

While what hereinbefore has been described as the preferred embodiment of this invention, it is readily apparent that many alterations and modifications can be resorted to without departing from the scope of this invention and dependent claims.

I claim:

1. A water defrost refrigerated showcase comprising: an open display bin, air circulating passages at the front and rear of said display bin, an air circulating passage beneath said display bin, a blower, refrigerating coils in said last mentioned passage through which coils refrigerant is circulated, and means in said last mentioned passage for spraying water over said refrigerating coils to defrost said coils, a tank for storing water for said spraying means, a ball valve controlling flow from said tank, and a float valve controlling flow into Said tank.

2. A water defrost refrigerated show case comprising: an open display bin, air circulating passages at the front and rear of said display bin, an air circulating passage beneath said display bin, a blower, refrigerating coils in said last mentioned passage through which coils refrigerant is circulated, and means in said last mentioned passage for spraying water over said refrigerating coils to defrost said coils, a tank for storaging water for said spraying means, a ball valve controlling fiow from said tank, and a float valve controlling flow into said tank, and control means for opening and closing said ball valve for a predetermined period.

3. A water defrost refrigerated showcase comprising: an open display bin, air circulating passages at the front and rear of said display bin, an air circulating passage beneath said display bin, a blower, refrigerating coils in said last mentioned passage through which coils refrigerant is circulated, and means in said last mentioned passage for spraying water over said refrigerating coils to defrost said coils, a tank for storing water for said spraying means, a ball valve controlling flow from said tank, and a float valve controlling flow into said tank, control means for opening said ball valve, means for actuating said control means to open said ball valve for a predetermined period of time, said last mentioned means shutting off said blower and terminating flow of refrigerant through said coils when said ball valve is opened.

4. A water defrost refrigerated showcase comprising: an open display bin, front and rear walls spaced from said display bin to form air passages therebetween, a bottom Wall spaced from said display bin, refrigerating means between said bottom wall and said display bin, a blower circulating air over said refrigerating means up one of said air passages over said display bin and back through the other of said air passages to be recirculated, and water spraying means positioned above said refrigerating coils, a drain pan beneath said refrigerating coils, and means for accumulating water sprayed over said coils in said pan for a predetermined time before draining said pan.

5. A water defrost refrigerated showcase comprising: an open display bin, front and rear walls spaced from said display bin to form air passages therebetween, a bottom wall spaced from said display bin, refrigerating means between said bottom wall and said display bin, a blower circulating air over said refrigerating means up one of said air passages over said display bin and back through the other of said air passages to be recirculated, and water spraying means positioned above said refrigerating coils, a pan beneath said refrigerating coils, a drain from said pan, valve means controlling flow through said drain, and means closing said drain for a predetermined time thereby collecting water sprayed over said refrigerating coils in said pan and utilizing heat given off by water so collected to defrost the refrigerating coils.

References Cited in the file of this patent UNITED STATES PATENTS 970,807 Faget Sept. 20, 1910 1,626,255 Roth Apr. 26, 1927 2,056,087 Andrews Sept. 29, 1936 2,323,511 Baker July 6, 1943 2,476,184 Goddard July 12, 1949 2,505,201 Peterson Apr. 25, 1950 2,524,568 Kritzer Oct. 3, 1950 2,528,916 Shreve Nov. 7, 1950 2,571,192 Brill Oct. 16, 1951 2,626,401 Blair a- Jan. 27, 1953 2,649,695 Kohlstedt Aug. 25, 1953

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