US3854302A

US3854302A - Defroster for a refrigerating system

Info

Publication number: US3854302A
Application number: US00392748A
Authority: US
Inventors: F Masuda
Original assignee: Sakura Refrigerating and Heating Engineering Co Ltd
Current assignee: Sakura Refrigerating and Heating Engineering Co Ltd
Priority date: 1972-09-13
Filing date: 1973-08-29
Publication date: 1974-12-17
Anticipated expiration: 1991-12-17

Abstract

A defroster for removing the frost deposited on the evaporator of a refrigerating system is so constructed that an antifreezing solution introduced into the refrigerating box of the system for preliminary cooling is sprayed on the frost to have its melting point reduced and the antifreezing solution diluted by the water of the melted frost is sprayed on the heat radiating coil member of the system to cause the water contained in the solution to be evaporated, thus increasing its concentration.

Description

United States Patent [191 Masuda Dec. 17, 1974 DEFROSTER FOR A REFRIGERATING I SYSTEM [75] Inventor: Fujio Masuda, Tokyo, Japan [73] Assignees Sakura Refrigerating & Heating Engineering Co., Ltd., Tokyo, Japan 22 Filed: Aug. 29, 1973 21 App1.No.:392,748

Related US, Application Data [63] Continuation-impart of Ser. No. 288,666, Sept. 13,

1972, Pat No. 3,772,897.

[30] 0 Foreign Application PriorityData Apr. 14, 1973 Japan 48-42601 [52] US. Cl...... 62/282, 62/82 [5 1] F2511 21/10 [58] Fieldvof Search 62/82, 151, 282

[56] v References Cited 0 UNITED STATES PATENTS 2,526,032 10/1950 La Porte 62/82 12 TUIL/ 2/1965 Persson 62/282 11/1973 Masuda 62/282 Primary ExaminerMeyer Perlin Attorney, Agent, or Firm--Flynn & Frishauf [571 ABSTRACT A defroster for removing the frost deposited on the evaporator of a refrigerating system is so constructed that an antifreezing solution introduced into the refrigerating box of the system for preliminary cooling is sprayed on the frost to have its' melting point reduced and the antifreezing solution diluted by the water of the melted frost is sprayed on the heat'radiating coil member of the system to cause the water contained in the solution to be evaporated, thus increasing its con- I centration. i

10 Claims, 4 Drawing Figures PAIENIEL 1. 854.302 sum 10F 3 1 DEFROSTER FOR A REFRIGERATING SYSTEM CROSS-REFERENCE To RELATED APPLICATION This is a continuation-in-part of US. Pat. application No. 3,772,897, issued Nov. 20, I973.

BACKGROUND oF THE INVENTION The present invention relates to a defroster, and more particularly to a defroster for removing the frost depositedon the evaporator. of a refrigerating system.

v lt is generallyknownthat refrigerating capacity is lowered due to frost being deposited on an evaporator such as a fin coil in a refrigerator or freezer. There have Ser. No. 288,666,filed .Sept. I3, 1972 now US. Pat.

system is connected through a pipe 13 to the input terminal of a compressor not shown. Connected through a pipe 15 to the output terminal of the compressor is a heat radiating coil 14 as will later be described. The coil 14 isconnected through a pipe 16 to the input terminal of a condenser 17. The output terminal of the condenser 17 is connected through a pipe 18 to a re- I 'ceiver and then to an expansion valve not shown, and

been heretofore used a variety of defrosters of, for example, hot-gas and electric heater type. The'conventional defroster, however, can not be operated during refrigeration due torequirement of a relatively high heat. Therefore, defrosting m'ust'be. preceded by the cessation of the refrigeration; operation. This causes the temperature of a refrigerator to be increased during the defrosting operation by the deenergization of a refrigerating 'cycle system and/or the heating operation of the defroster. Even after the refrigerating cycle is started again, it is impossible to lower the temperature through a pipe 19 to the evaporator.

A refrigerant performs a predetermined refrigerating function through a cycle system including an evaporator, compressor, condenser, receiver and expansion valve'as is well known in theart.

A defrosting device according to the present invention comprises an'antifreezing solution-circulating system for defrosting," I an antifreezing solutionconcentrating system and an antifreezing solution tank The antifreezing solution-circulating system includes to introduce the antifreezing solution into the-casing of the refrigerator to a predetermined level in a short.

time. Moreover, a forceful attempt to decrease said temperature gives rise to various inconveniences. Furthermore, the prior art refrigerating operation is inter- The object ofthe present invention is to provide a defroster capable of being easily incorporated in a refrig-' crating-cycle system and'removing the frost deposited on the evaporator during refrigeration without stopping or interrupting the refrigerating operation and applying a relatively hightemperaturewhich would obstruct the regular refrigerating operation.

SUMMARY OF THE INVENTION Ina defroster accordingto the present invention, an antifreezing solution introducedinto a refrigeratingor cold box for preliminary cooling issprayed on a frostclad evaporator to decrease the melting point of the frost. Then, the antifreezing solution diluted by the water 'of the melted frost is heated to cause the water therein to be evaporated, increasing its concentration.

The solution thus concentrated is again used for defrosting.

BRIEF DESCRIPTION OF THE'DRAWINGS FIG. 1 is a schematic view showing a defroster according to an embodiment of the present invention;

FIGS. 2 and 3 are respectively enlarged'front and side views of partof the defroster shown in FIG. 1, illustrating a cooler casing arid some members accommodated therein; and v cooler casing.

I DETAILED DESCRIPTION OF THE INVENTION Description is now given of a defroster according to an embodiment of the present invention, as applied in,

a refrigerating cycle system. Since the refrigerating cycle system shown in FIG; 1 may be of known type,

mittently effected, resulting in added cost. I

an inlet pipe 22 having one end connected to the tank" 20 and the other end thereof inserted into thecasing 11 from the tank 20 bythe. pumping action of a pump 21. Situated above the evaporator coil 12 in the casing 11 is the inserted end of the pipe 22 which sprays the antifreezing solution through its nozzle 23 on a frost layer deposited "on the fin coil. Disposed below the coil 12 I 4 are a precooler 27 and a funnel-type tray 24, the later collecting the sprayed solution containing the water melted from the frost. Connected to the outlet of the tray 24 is one end of an outlet'pipe 25', the other end of which is connected to the. tank 20.'The arrangement v FIG. 4 l5 a plan view of a precooler received mthe enables the antifreezing solution collected in the tray 24 to be returned to the tank.

The inlet pipe 22 is fitted with the precooler 27, a

:manually operable valve 37 and check valve 36 for sending, for a predetermined time, a controlled amount of precooled antifreezing solution to the evaporator.

The precooler 27 is disposed in the casing 11 between the evaporator coil 12 and'tray 24. The antifreezing solution led through the check valve 36 from the tank 20 is sent to the precooler 27 where the solution is pre-.

cooled by the water melted from the frost as well as by an external atmosphere cooled by the evaporator. I

In the embodiment according to the present invention, the cooling function of the precooler 27 is assisted by the inlet and o utlet pipes 22 and 25'which are associated with each otheroutside the refrigerator 10 to constitute a heat exchanger 26. The heat'exchanger 26 cools for the reason given below the antifreezing solution at a relatively high temperature passing through the inlet pipe 22 by the antifreezing solution at a relatively low temperature passing through the outlet pipe 25, thereby precooling. the former solution before it enters the precooler 27. Heat transfer may be effected by either arranging the portions of the inlet pipe and outletv pipe in a concentric relationship, or spirally winding the portion of the outlet pipe around the corresponding portion of the inlet pipe. Since the-antifreezing solution is sufficiently cooled by these two cooling mecha- '

nisms

26, 27 before being sprayed on the evaporator blower 29 for upwardly directing an air stream in will not be lowered, even if the antifreezing solution is sprayed on the'evaporator.

Disposed above the nozzle 23 in the cooler casing 11 is an eliminator 28 for preventing the escape from the casing 11 of the antifreezing solution sprayed from the nozzle 23. Also located above the eliminator 28 is a the casing 11 to enhancethe defrosting effect. The antifreezing solution-concentrating circulation system includes a concentrator 30 containing the heat radiating coil 14, and an inletpipe 32 for introducing, by the action of a pump 31, the antifreezing solution from the tank into the concentrator 30. Fitted'to the end of the inlet pipe 32 in the concentrator 30 is a nozzle 33 which is situated above the coil 14. The antifreezing solution from the tank 20 is sprayed through the nozzle 33 on the heat radiating coil 14. This causes some water contained in the sprayed solution to be evaporated, since a refrigerant at a relatively high temperature passes through the heatradiating coil 14. Thus the antifreezing solution is' concentrated during the spraying operation. Disposed below the radiating coil '14 in the concentrator 30 is a funnel-like tray 34 for collecting the antifreezing solution thus concentrated.

The outlet of the tray 34 is connected to the tank 20 measuring device 38 of float type for measuring the level of the antifreezing solution in thetank 20.'This device is connected to switch means 39 for selectively driving the pump 31. As a result, when the antifreezing solution in the tank 20-reaches a higher level than predetermined, i.e., the solution has its concentration reduced, the pump 31 is automatically actuated to start the concentration system.

There will now be described the operation of the defroster according to the present invention, i.e., the step of supplying the condenser'l7 with a high-temperature and high-pressure gaseous refrigerant delivered from the compressor and the step of cooling the inside of the refrigerating box 10 through evaporation of the liquefied refrigerant in the evaporator coil 12.

The antifreezing solution in the tank'20 is heated to a fairly high temperature through the concentrating circulation system and then conducted through the heat exchanger 26 to the precooler 27. Then the solution is sprayed through the nozzle 23 on the coil. 12 to cause the frost deposited thereon to be thawed. The antisuch as the radiator coil 14 through which the high temperature refrigerant travels, so that the diluted antifreezing solution is evaporated for concentration. The

concentrated high temperature antifreezing solution is collected in the tray 24 and then returned to the tank 20, where it is mixed with the diluted antifreezing solution from the defrosting cycle to maintain its concensembled frame members. The tray 24 is firmly secured to the frame support 41 by reinforcing members 42 fitted tothe periphery of the underside of said tray 24. Arranged in the body 1 la are the evaporator 12, nozzle assembly 23, eliminator 28 andblower 29 in the order mentioned as counted from the bottom. The precooler 27 is disposed between the tray 24 and evaporator 12. The liquid outlet of the precooler 27 and the nozzle assembly 23 are connected together by a connection pipe 43. The precooler 27 comprises, as shown in FIG. 4, a plurality of (eight in this embodiment) linear. pipes 44 arranged parallel at a small interval, an end pipe 45 fitted in common to the ends on one side'of-the linear pipes 44 on one side for their joint connection, an end pipe 46a fixed in common to theends on the opposite.

of four of the'linear pipes 44 for their joint connection, and an end pipe 46b secured in common to the ends on the opposite side of the remaining four of the linear pipes 44 for their joint connection. The end pipe 46a is provided with a liquid inlet 47a and the end pipe 46b with a liquid outlet 47b. The liquid outlet 47b is connectedto the nozzle assembly 23 through theco nnection pipe 43 and the liquid inlet 47a is connected to the solution tank 20 through the pipe 22 (FIG. 1).

The blower 29 is received in a support frame 48 above the eliminator 28. The blower 29 comprises fans 52 and a motor 51 for their drive. One of the panels constituting the side walls of the frame support 48 is bored with exhaust openings 49, Received in the frame support 48 are du'cts'53. for conducting air from the fans 52 to the exhaust openings 49. An air inlet 54 is provided between the frame support 41- and casing body 11a. Accordingly, the rotation of the fans 52- causes the air in the refrigerating box 10 to be introduced into the casing body lla through the inlet 54 in the direction of the indicated arrow. After being cooled in the evaporator 12, the air is brought back into the refrigerating box 10 from the exhaust openings 49 I through the eliminator 28 and a duct-53 (FIG. 3). In

freezing solution diluted by the water, .of the melted frost passes over the outer surface of the precooler -27- to be collected in the tray 24 and sent back'to the tank 20 by way of the pipe 25. In this case, the antifreezing solution returned'to the tank is diluted by the water of the melted frost to have its quantity increased. However, according to the present invention the diluted antifreezing solution is concentrated through the concentration cycle to render the concentration of the solution in the tank constant at all times. That is, the antifreezing solution in the tank is heated by heating means this case, the volume of air is controlled by an air volume-controlling window 50 bored in one of the side walls of the frame support 48 and designed to have the degree of opening freely adjusted.

Since the precooler 27 .is located between the tray 24 and evaporator 12, the antifreezing solution brought to the precooler 27 consisting of the cooling

pipes

44, 45, 46a and 46b is cooled when a separate portion of the antifreezing solution sprayed through the nozzle assembly 23 and cooled by melting the frost deposited on the evaporator 12 continuously wets the surface of the cooling

pipes

44, 45, 46a and 46b. Since the precooler 27 is positioned near the evaporator 12, the antifreezing solution passing through the precooler 27 is also cooled by the external atmosphere already cooled 'by the evaporator 12. Accordingly, the antifreezing solution conducted through the precooler 27 is fully cooled, preventing the refrigerating capacity of the evaporator 12 from being decreased even when the antifreezing solution is sprayed on the evaporator 12 through the nozzle assembly 23. As a result, defrosting can be effected without stopping the regular refrigerating operation.

The foregoing embodiment refers to the case where the precooler 27 was provided near the evaporator 12 so as to let the external atmosphere cooled by said evaporator 12 assist in cooling the antifreezing solution passing through the precooler 27. However, it is possible to place the precooler 27in the tray 24 so as to be immersed in a separate portion of the antifreezing solution whichdrips from the evaporator 12 into the tray 24 after being cooled by melting the frost deposited on the evaporator 12, thereby cooling the antifreezing solution passing through the precooler 27. In this case, it is of course necessary to control the amount of antifreezing solution sprayed from the nozzle assembly 23 and that drawn out from the tray through the outlet pipe 25 so as to cause a fixed amount of antifreezing solution to be always collected in the tray 24.

In the above-mentioned embodiment, means for heating the diluted solution consisted of the heat radiating coil 14 of the refrigeration system. However, it is possible to use other heating means such as a condenser or a combination of a main and an auxiliary heating device. For example, the heating coil indicated by numeral 55 in H6. 1 may be used as auxiliary heat ing'means for heating the antifreezing solution successively brought to the tank The defrosting circulation system of the defroster according to the present invention may be operated either continuously during refrigeration, or intermittently by means of a timer, etc. Otherwise, the defrosting circulation system of the defroster may be operated only for a length of time determined according to the amount of frost deposited on the coil 12.

What is claimed is:

1. A defroster for removing the frost deposited on the surface of the evaporator of a refrigerating system which comprises spray means for spraying an antifreezing solution on the evaporator to remove the frost deposited on the evaporator; an antifreezing solution tray 2. A defroster according to claim 1 wherein the means for conducting the antifreezing solution to the lution thus concentrated being circulated to the precooler.

3. A defroster according to claim I wherein the precooler includes a plurality of cooling pipes arranged parallel and connected together in the same horizontal plane to face the evaporator, said pipes permitting the passage of the antifreezing solution.

4. A defroster according to claim 3 wherein the precooler is positioned so near the evaporator as to cause the antifreezing solution running through the precooler to be also cooled by the external atmosphere already cooled by the evaporator.-

5. A defroster according to claim 3 wherein the precooler is disposed in the antifreezing solution tray so as to be cooled by being immersed in the antifreezing solution collected in the tray after being cooled by melting-the frost deposited on the evaporator.

6. A defroster for a refrigerating cycle system including a hollow refrigerating box, an evaporator for refrigerating a mass contained in the refrigerating box and a heat radiating member-through which a heated refrigerant passes, which comprises a tank for receiving an antifreezing solution; first means for conducting the antifreezing solution from the tank to the evaporator to reduce the melting point of the front deposited on the evaporator, thereby facilitating the melting of the frost; second means for returning the antifreezing solution diluted by the water of the melted frost to the tank to collect the solution therein; third means for delivering the antifreezing solution from the tank to the heat radiating member to concentrate the solution by evaporation; and fourth means for circulating the concentrated antifreezing solution back to the tank to collect the solution therein, the. first means having precooling means disposed below the evaporatorto cool the antifreezing solution running through the first means by a separate portion of the antifreezing solution diluted by the water freezing solution for concentration before the antia separate portion of the antifreezing solution which i has been cooled by melting the frost deposited on the evaporator; and means for conducting the antifreezing solution collected in the tray to the spray means freezing solution is sent to the precooler.

9. A defroster according to claim 8 wherein the auxiliary heating means includes a coil heater for heating the antifreezing solution successively introduced into the tank. 1

10. A defroster according to claim 6 wherein said tank includes a device for measuring the level of liquid contained in the tank and switch means connected to the measuring device to operate the third means when the antifreezing solution in the tank reaches a higher level than predetermined.

Claims

1. A defroster for removing the frost deposited on the surface of the evaporator of a refrigerating system which comprises spray means for spraying an antifreezing solution on the evaporator to remove the frost deposited on the evaporator; an antifreezing solution tray positioned below the evaporator so as to receive the antifreezing solution sprayed on the evaporator and dripping therefrom after melting the frost deposited thereon; a precooler located between the tray and evaporator to cause the antifreezing solution passing through the precooler to be cooled from the outside by a separate portion of the antifreezing solution which has been cooled by melting the frost deposited on the evaporator; and means for conducting the antifreezing solution collected in the tray to the spray means through the precooler, whereby the antifreezing solution flowing through the precooler is precooled from the outside by a separate portion of the antifreezing solution which has been cooled by melting the frost deposited on the evaporator and thereafter being sprayed again on the evaporator by the spray means.

2. A defroster according to claim 1 wherein the means for conducting the antifreezing solution to the spray means through the precooler is provided with means for thermally concentrating the antifreezing solution diluted by melting the frost, the antifreezing solution thus concentrated being circulated to the precooler.

3. A defroster according to claim 1 wherein the precooler includes a plurality of cooling pipes arranged parallel and connected together in the same horizontal plane to face the evaporator, said pipes permitting the passage of the antifreezing solution.

4. A defroster according to claim 3 wherein the precooler is positioned so near the evaporator as to cause the antifreezing solution running through the precooler to be also cooled by the external atmosphere already cooled by the evaporator.

5. A defroster according to claim 3 wherein the precooler is disposed in the antifreezing solution tray so as to be cooled by being immersed in the antifreezing solution collected in the tray after being cooled by melting the frost deposited on the evaporator.

6. A defroster for a refrigerating cycle system including a hollow refrigerating box, an evaporator for refrigerating a mass contained in the refrigerating box and a heat radiating member through which a heated refrigerant passes, which comprises a tank for receiving an antifreezing solution; first means for conducting the antifreezing solution from the tank to the evaporator to reduce the melting point of the front deposited on the evaporator, thereby facilitating the melting of the frost; second means for returning the antifreezing solution diluted by the water of the melted frost to the tank to collect the solution therein; third means for delivering the antifreezing solution from the tank to the heat radiating member to concentrate the solution by evaporation; and fourth means for circulating the concentrated antifreezing solution back to the tank to collect the solution therein, the first means having precooling means disposed below the evaporator to cool the antifreEzing solution running through the first means by a separate portion of the antifreezing solution diluted by the water of the melted frost.

7. A defroster according to claim 6 which further comprises a heat exchanger constituted by the portions of the first and second means to cool the antifreezing solution passing through the first means by the antifreezing solution flowing through the second means.

8. A defroster according to claim 6 which further comprises auxiliary heating means for heating the antifreezing solution for concentration before the antifreezing solution is sent to the precooler.

9. A defroster according to claim 8 wherein the auxiliary heating means includes a coil heater for heating the antifreezing solution successively introduced into the tank.