US3772897A

US3772897A - Defroster for a refrigerating system

Info

Publication number: US3772897A
Application number: US00288666A
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: 1972-03-21
Filing date: 1972-09-13
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20
Also published as: AU4656172A; BR7301929D0; GB1375428A; JPS4895642A; SU469271A3

Abstract

A defroster removes a frost deposited onto an evaporator of a refrigerating system. The defroster is so constructed that an anti-freezing solution preliminarily introduced and cooled within the refrigerating box of the system is sprayed onto the frost to lower the fusing point thereof and the anti-freezing solution diluted by the frost is sprayed onto 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 Nov. 20 1973 [54] DEFROSTER FOR A REFRIGERATING 2,526,032 10/1950 La Porte 62/82 SYSTEM 2,672,024 3/1954 McGrath.... 62/282 2,747,382 5/1956 Sloan 62/282 [75] Inv nt r: Fu l Masud ,T0ky0. p 2,748,574 6/1956 Gaston 62/282 [73] Assignee: Sakura Refrigerating & Heating Engineering Co., Ltd., Tokyo, Japan Primary ExaminerWilliam J. Wye [22] Filed: Sept- 1972 Att0meyRobert'D Flynn et al.

[21] A 1. No.: 288 666 pp 57 ABSTRACT 30 Foreign Application priority n; A defroster removes a frost deposited onto an evapo- Mar 21 1972 Japan 47/27494 rator of a refrigerating system. The defroster is so constructed that an anti-freezing solution preliminarily in- 52 U.S. Cl. 62/282 62/82 and within the refrigerating box 51 Int. ....:I I F25d 21/10 the System is Sprayed the fusmg [58] 6 Field of Search 2/82 282 point thereof and the anti-freezing solution diluted by the frost is sprayed onto the heat radiating coil mem- [56] R'eerences Cited ber of the system to cause the water contained in the solution to be evaporated, thus increasing its concen- UNITED STATES PATENTS nation 2,323,511 7/1943 Baker 62/282 3 Claims, 1 Drawing Figure 3 l 7\ fl --u E 5}. l4 4 f 21 H n @c "j 16 r "3 O I 5-: 7 37 5 34 DEFROSTER FOR A REFRIGERATING SYSTEM The present invention relates to a defroster, particularly to a defroster for removing a frost deposited onto an evaporator of a refrigerating system.

It is generally known that a refrigeration capacity is lowered due to a frost deposited onto an evaporator such as a fin coil in a refrigerator, freezer etc. in general. There has been heretofore proposed a variety of defrosters such as for example a hot-gas type, electric heater type currently in use. The conventional defroster, however, can not be operated during a refrigeration cycle due to a high heat involved. Therefore, in order to attain a defrost it is necessary to stop or interrupt the refrigeration operation. For this reason a temperature within a refrigerator is increased during the operation of the defroster by the deenergization of a refrigerating cycle system and/or the heating operation of the defroster. Even after resuming the refrigerating cycle it is impossible to lower the temperature within the refrigerator up to a predetermined level unless lapsed for a predetermined period of time. During the time period various inconveniences will also be caused. Furthermore, the refrigeration operation of the refrigerating cyclic system is intermittently effected in the prior art refrigerator, resulting in an added operation cost.

The object of the present invention is to provide a defroster capable of being incorporated easily into a refrigerating cycle system and capable of removing a frost deposited during the refrigeration cycle onto the evaporator without stopping or interrupting the refrigeration operation and without using a high temperature which causes some inconveniences in the refrigeration treatment. I

In the defroster according to the present invention use is positively made of the heat of a high-temperature high-pressure gaseous refrigerant circulating in the high pressure side of a refrigerating cycle system in general. An anti-freezing solution preliminarily introduced and cooled in a refrigerating or cold box for a predetermined period of time is sprayed onto a frostdeposited evaporator to cause the frost to lower its fusing point. Then, the anti-freezing solution diluted by the front is sprayed onto the means, through which a high-temperature high-pressure gaseous refrigerant is passed, to cause the water in the diluted solution to be evaporated, thus increasing its concentration. The so concentrated liquid is again used for defrosting.

According to an aspect of the invention there is provided a defroster for a refrigerating cycle system having a refrigerating box definging a space therein, an evaporator for refrigerating said space and a heat radiating member through which a heated refrigerant is passed; comprising a tank for receiving a anti-freezing solution, first means for supplying the anti-freezing solution from the tank to the evaporator so as to lower the fusing point of the frost deposited on the evaporator to melt the frost, second means for collecting and returnlng to the tank the anti-freezing solution diluted by the thawed frost, third means for supplying the antifreezing solution from the tank to the heat radiating member to evaporate it for concentration, fourth means for collecting and returning to the tank the concentrated anti-freezing solution, and pre-cooling means mounted in the refrigerating box to cool the antifreezing solution passing through the first means by a cold atmosphere in the space of the box.

FIGURE is a schematic, systematic view showing a defroster according to an embodiment of the present invention.

Explanation is now made of a defroster according to an embodiment of the present invention, as applied in a refrigerating cycle system. Since the refrigerating cycle system as shown in the FIGURE may be ofa generally known type, explanation is restricted only to the evaporator and condenser thereof.

in a unit cooler casing 11 provided in the space of a refrigerating box 10 there is housed an evaporator 12 consisting of fin coils. The evaporator 12 constituting one essential element of the known refrigerating cycle 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 is connected through a pipe 16 to the input terminal of a condenser 17. The output terminal of the condensor 17 is connected through a pipe 18 to a receiver and then an expansion valve not shown, and through a pipe 19 to the evaporator.

' A refrigerant performs a predetermined refrigerating function through a cycle including the evaporator, compressor, condenser receiver and expansion valve as is well known inthe art. I

A defrosting device according to the present invention comprises an anti-freezing solution circulating system.for defrosting, an anti-freezing solution concentrating system and an anti-freezing solution reservoir tank 20 shared with both the systems.

The anti-freezing solution circulating system includes an inlet pipe 22 having one end connected to the tank 20 and the other end thereof extending within the casing 11 to introduce the anti-freezing solution in to the casing from the tank 20 under the pumping action of a pump 21. Situated above the evaporator coil 12 within the casing 11 is the extended end of the pipe 22 whichspraysthe anti-freezing solution through its no:- zle 23 onto a frost layer deposited on the fin coil. Below the coil 12 there is provided a funnel-like tray 24 for collecting the sprayed solution containing the water melted from'the frost. To the outlet of the tray 24 is connected one end of an outlet pipe 25 the other end of which 'is connected to the tank 20. The arrangement permits the anti-freezing solution collected within the tray to be returned to the tank.

At the inlet pipe 22 there areprovided a pre-cooler 27, manually operating valve. 37 and check valve 36 for sending, for a predetermined time period, a controlled amount of pre-cooled anti-freezing solution onto the evaporator. The pre-cooler' 27 is disposed at the corner in the space of the refrigerating box 10 to give not so much affect to the refrigeration effect, and the antifreezing solution is cooled by a lower temperature atmosphere within-the refrigerator. The pre-cooler 27 may take a variety of forms but, as a preferable form, use is made of bent rectangular pipes arranged one over the other at a multi-stepped, spaced-apart relation to raise a cooling effect with a smaller space occupied. The anti-freezing solution led through check valve 36 from the tank 20 is sent to the pre-cooler 27 where it is held and pre-cooled for a predetermined period of time. The pre-cooled liquid, as required, is supplied at a desired flow amount onto the evaporator 12 through a check valve 36.

In the embodiment according to the present invention, to assist the cooling function of the pre-cooler 27 the inlet and outlet pipes 22 and 25 are associated with each other outside the refrigerator to constitute a heat exchanger 26. The heat exchanger 26 functions to cool that anti-freezing solution passing through the inlet pipe 22 raised to a relatively high temperature for the reasons set out below by that relatively lowtemperature anti-freezing solution passing through the outlet pipe 25 thereby precool the former solution before entry into a pre-cooler 27. The heat transfer, for example, may be formed by either arranging the portions of the inlet pipe and outlet pipe at a coaxial array, or spirally winding the portion of the outlet pipe around the portion of the inlet pipe. Since the anti-freezing solution is sufficiently cooled by these two

cooling mechanisms

26, 27 before being sprayed onto the evaporator 12, it will be understood that no refrigeration capability will be lowered, even if the anti-freezing solution is sprayed onto the evaporator.

Disposed above the nozzle 23 in the unit cooler casing 11 is an eliminator 28 for preventing an escape from the casing 11 of the anti-freezing solution sprayed from the nozzle 23. Also located above the eliminator 28 is a blower 29 for generating an upward directing air stream within the casing 11 to enhance a defrosting effeet.

The anti-freezing solution concentrating circulation system includes a concentrator 30, in which the heat radiating coil 14 is contained, and an inlet pipe 32 for introducing, under the action of a pump 31, the antifreezing solution from the tank into the concentrator 30. Mounted at the end of the inlet pipe 32 and within the concentrator is a nozzle 33 which is situated above the coil 14. Through the nozzle 33 the antifreezing solution from the tank 20 is sprayed onto the heat radiating coil 14. This will cause some water contained in the sprayed solution to be evaporated since the high-temperature refrigerant is passed through the heat radiating coil 14. From this it will be understood that during the spraying the anti-freezing solution will be concentrated. Arranged below the radiating coil 14 within the concentrator is a funnel-like tray 34 for collecting the so-concentrated anti-freezing solution. The outlet of the tray 34 is connected to the reservoir tank 20 through an outlet pipe 35. As a result the concentrated anti-freezing solution is returned to the tank.

Within the concentrator 3( an eliminator 40 is provided to trap droplets of the anti-freezing solution thereon, thereby preventing the dissipation of the solution. As a result only water vapor can be passed upwardly. Below the coil 14 there is disposed a blower for facilitating heat dissipation of the coil 14.

On the tank 20, for example, a liquid-level measuring device 38 of floating type is provided for measuring the liquid level of the anti-freezing solution within the tank.

This device is connected to a switch means 39 for selectively driving the pump 31. As a result when the antifreezing solution within the tank 20 is reached at more than a predetermined level, i.e., the solution has its concentration reduced the pump 31 automatically starts its operation to get the concentration system into warks.

Let us now explain the refrigeration cycle of the defroster according to the present invention, i.e., the aspect of sending to the condenser 17 a high-temperature and high-pressure gaseous refrigerant caused by the compressor and the aspect of cooling the inside of the refrigerating box 10 through evaporation of the liquefied refrigerant in the evaporator coil 12.

The anti-freezing solution within the tank 20 is raised to a fairly high-temperature through the concentrating circulation system which is then sent through the heat exchanger 26 to the pre-cooler 27 where it is precooled for a predetermined period of time. Then it is sent to the nozzle 23, through which it is sprayed onto the coil 12 to cause the frost deposited thereon to be thawed. The anti-freezing solution diluted by the thawed water is collected in the tray 24 and sent back to the tank 20 by way of the pipe 25. In this case the anti-freezing solution so returned to the tank is diluted and extended by the thawed water. However, according to the present invention the diluted solution is concentrated through the concentration cycle to maintain at all times constant the concentration of the anti-freezing solution within the tank. That is, the anti-freezing solution within the tank is sprayed onto the radiator coil 14 through which the high-temperature refrigerant is passed so that the diluted anti-freezing solution is evaporated to cause it to be concentrated. The soconcentrated high-temperature anti-freezing solution is collected in the tray 34 and then returned to the tank 20, where it is mixed with the diluted anti-freezing solution from the defrosting cycle. Thus, the concentration of the solution within the tank 20 is maintained constant.

The defrosting circulation system of the defroster according to the present invention may be operated either continuously during the operation of the refrigeration cycle, or intermittently by means of a timer etc. Otherwise the defrosting circulation system of the defroster may be operated only for a predetermined period of time, taking into consideration the extent to which a frost is deposited onto the coil 12. Though as the concentration means diluting anti-freezing solution the heat radiating coil is used in the present embodiment, the other means, such as for example a condenser, through which a high-temperature gaseous refrigerant is passed, may be used.

What is claimed is:

l. A defroster for a refrigerating cycle system having a refrigerating box defining a space therein, an evaporator for refrigerating said space and a heat radiating member through which a heated refrigerant is passed; comprising a tank for receiving an anti-freezing solu' tion, first means for supplying the anti-freezing solution from the tank to the evaporator so as to lower the fusing point of the frost deposited on the evaporator to melt the frost, second means for collecting and returning to the tank the anti-freezing solution diluted by the thawed frost, third means for supplying the antifreezing solution from the tank to the heat radiating member to evaporate it for concentration, fourth means for collecting and returning to the tank the concentrated antifreezing solution, and pre-cooling means mounted in the refrigerating box to cool the antifreezing solution passing through the first means by a cold atmosphere in the space of the box.

2. A defroster according to claim 1, further including a heat exchanger constituted by the parts of the first and second means to cool the anti-freezing solution in switch means connected to the device to operate the third means when the anti-freezing solution in the tank is reached at more than a predetermined level.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N 7 3 Dated November Inventor(s) j'iO MASUDA It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Abstract:

line 1 change "removes" to --for removing- V line 2, after "systems" delete The defroster";

Column 1 line 3 after "defroster," insert and more--;

line 4, delete "a" (second occurrence) lines 6 and 7, delete "a" line 10, after "type," insert and an--; I line 13 delete "a" 1 insert --the-;

"line 15, after reason" delete "a" and insert the-;

, line 21 delete "up" lines 21 and 22, delete "unless lapsed for a predetermined" and insert in a short; line 22, after "During" change "the" to --this--; a line 26, after "resulting in" delete "an" line .31 after "removing" delete a" between lines 36 and 37 insert the heading Summary of the Inventionline 46, after "means" delete line 53, ehange "definging" to defining line 55, after "passed" delete insert line 56, delete "comprising" insert I'he defroster comprises--; change "a" (last occurrence) to --an-;

FoRM PO-1050 (10-69) USCOMWDC l-Ls. GOVEINMIkT PIINTIHG OFFICE II. oP'all'lal,

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,772,897 Dated November 20,- 1973 Inventor(s) F ji-0 'MASUDA I It'is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

. a Column 2, between lines 2 and 3 insertthe heading Brief Description of the Drawingline 3, change "FIGURE" to The single Figure--; between lines 5 and 6 insert the heading ---De'tailed Description of the Drawing--; line 1 2, after "space" change "of" to' -within--; line 14, change "consisting of" to --including--; line 50, after "tray" insert --24- f linef52, change "operating" to --operated-; line 62, after "other" change at to inline 63 after "raise" change "a" to '--the---; last line, change "at" to -with-;

Column 3, line 1,. after "desired" insert amount of--;

after "flow" delete "amount" line' 2, change "a" to -the; I line 12, after-"pipe 25" insert --to-; linefIS, after "outlet p'ipe"-'change,"a't" to --in-; line 20, change "no" to the--; line 21 after "will" insert -'-'not-; I line 24, after "preventing" change- "an" to -the-- line 27, change "upward directing" to upwardly directed-; line 28, change "a" to the--; line 58, change "floating" to th float--; line 62, delete "is reached at more""and insert reaches a level higher--;

FORM Po-1oso (10-69) USCOMM DC 603764 69 U.. GOVERNMENT PRINTING OFFICE I9" 0-Jl-ISL UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 772 897 Dgt d November 20', 1 973 Inventor(s) Fuj i0 MASUDA It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below;

Column 3', line 64, after reduced' insert line 65, change "get" to --start--; line 66, change "warks" to --operationline 67, delete "Let us now explain" and insert -There will now be explained-;

Column 4,; line 4, change lique--"v to -.-li-qui v "

lines

19 and 20, delete "at all times constant" line 21 after "the tank" insert -constant at' all timeS- I I line 27, change 'tray 34" to -tray 24-; li ne 40," vafter "which" delete "a" ;'c hange "onto" to --on--; delete "Though" insert -"-While a heat radiating coil is-used--; line 42, delete "the heat radiating coil is used" 7 line 43 before "other" delete the line 59, delete "concentration" insert concentrating the .antifreezing solutionline 66, change "constituted by" to -.-'-comprised- Column 5, line 4 change "has" to --j 1 Column 6, last line; delete is reached at Qre" insert -reaches a level higher--;

Signed and sealed this th day of June 197M,

(SEAL) Attest:

EDWARD MJLETCERJR. I T CrMARSHALLDANN Attestina; Officer Y Commissioner of Patents F RM -105O (10-69) USCOMM DC 60310 P69 I I i U. S. GOVEIIIMENT PRINTING OFflE I95, O-QlC-SSL

Claims

1. A defroster for a refrigerating cycle system having a refrigerating box defining a space therein, an evaporator for refrigerating said space and a heat radiating member through which a heated refrigerant is passed; comprising a tank for receiving an anti-freezing solution, first means for supplying the anti-freezing solution from the tank to the evaporator so as to lower the fusing point of the frost deposited on the evaporator to melt the frost, second means for collecting and returning to the tank the anti-freezing solution diluted by the thawed frost, third means for supplying the anti-freezing solution from the tank to the heat radiating member to evaporate it for concentration, fourth means for collecting and returning to the tank the concentrated antifreezing solution, and precooling means mounted in the refrigerating box to cool the antifreezing solution passing through the first means by a cold atmosphere in the space of the box.

2. A defroster according to claim 1, further including a heat exchanger constituted by the parts of the first and second means to cool the anti-freezing solution in the first means by the anti-freezing solution in the second means.

3. A defroster according to claim 1 wherein said tank has a device measuring the liquid level in the tank and switch means connected to the device to operate the third means when the anti-freezing solution in the tank is reached at more than a predetermined level.