JPH01296067A - Defrosting in two-element refrigerator and its device - Google Patents

Abstract

PURPOSE:To make it easy to carry out maintenance and to conserve energy by making a high pressure gaseous coolant compressed by a secondary side compressor pass through a heat transfer pipe through which a primary side coolant of an evaporator on the primary side passes and through another separately provided flow channel from a branched pipe of the discharge pipe of the compressor. CONSTITUTION:In a primary side evaporator 1 a heat transfer pipe 2 for a primary side coolant and a heat transfer pipe 22 for a secondary side coolant which has a separate flow channel are separately provided. The discharge pipe 13b of a compressor 13 on the secondary side is provided additionally with a discharge three-way valve 20 and an one-way opening 20a is branched therefrom, and the one-way opening 20a is led to a secondary side heat transfer pipe 22 of a primary side evaporator 1 via a branch pipe 21. The secondary side high-pressure liquid coolant condensed in the secondary side coolant transfer pipe 22 goes via a pipe 26 and its pressure is reduced by an expansion valve 25 for defrosting and is led to a heat exchanger 23 for defrosting or a heat exchanger both for the secondary side condenser and acting as defrosting in combination, and there exchanges heat with air, water or others to be evaporated and the evaporated coolant is returned via the one-way opening of a suction three-way valve 27 provided on the suction pipe 13a of the secondary side compressor 13 again to the secondary side.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heat exchanger tube of an evaporator of a binary refrigerator used to obtain ultra-low temperature in refrigeration and freezing equipment for freezing food or in the chemical industry, etc. The present invention relates to a defrosting method and apparatus for a binary refrigerator for defrosting frost generated on the low-temperature air side.

[Conventional technology]

In recent years, binary refrigerators have been used to cool air to obtain ultra-low temperatures, but if the cooling operation is performed for a long time, frost will form on the low-temperature air side of the heat transfer tube section of the evaporator, reducing efficiency. . Therefore, conventional methods and devices for defrosting the evaporator of binary refrigerators include installing electric heaters in the heat transfer tubes, and using brine (an aqueous solution mixed with certain chemicals) that does not freeze at low temperatures.
Some use it as a defrosting heat source by spraying it on heat transfer tubes.

[Problem to be solved by the invention]

In the conventional method and device for defrosting the evaporator of a dual-component refrigerator, when an electric heater is used, when performing defrosting, the single-compressor and dual-compressor are stopped, and the electric heater for defrosting is stopped. A capacity approximately equal to the electric power capacity of the motor that drives these compressors is required.Depending on the scale of the binary refrigerator, this capacity may not be sufficient, and a larger capacity electric heater is required. Since the internal temperature of a refrigerator equipped with an evaporator is around -60 to -80°C, the surface heat generation temperature of the electric heater is increased and a confidential damper is installed at the air inlet and outlet of the evaporator to prevent the influence of the internal temperature. In addition to the high equipment costs for large-capacity electric heaters and their operating costs, the equipment costs for airtight dampers with complicated moving parts at low temperatures are also high. There are drawbacks.

In addition, with the brine distribution method, since the brine has a large heat capacity, defrosting can be performed without being affected by the temperature inside the refrigerator, but it requires a relatively long and thick brine supply pipe and discharge pipe to reach the inside of the refrigerator. In addition, it is necessary to install a brine circulation pump, etc., which increases the equipment cost, and when defrosting is repeated, the brine is diluted by the moisture that melts the frost each time, and the transmission of the evaporator is reduced. Since there is a possibility of freezing in the heat pipes, concentrators must be installed to constantly control the concentration, which is cumbersome. Electric heaters are required to condense the brine, and these equipment and operations are complicated. The disadvantages are that electric power is required for this purpose, the equipment cost is high, and it does not meet the demand for energy conservation.

The present invention does not require equipment such as electric heaters or low-temperature brine;
It is an object of the present invention to provide a defrosting method and device for a binary refrigerator that can avoid these troublesome managements, are easy to maintain, and can save energy.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a single-side evaporator that evaporates a single-side refrigerant and removes heat from the air inside the refrigerator in a refrigerator surrounded by a heat insulating wall, and provides a single-side evaporator for removing heat from the air inside the refrigerator. The side refrigerant gas is compressed by a single-side compressor, and a binary-side condenser and a binary-side expansion valve are sequentially installed on the inlet side, the suction side of the binary-side compressor is placed on the outlet side, and the discharge side of the compressor is installed. is introduced into the single-side condenser connected to the dual-side condenser, and the single-side refrigerant is evaporated in the single-side condenser to condense the single-side refrigerant. In a binary refrigerator that supplies liquid to the primary side evaporator, the discharge pipe from the binary side compressor to the binary side condenser is branched, and the high pressure gas refrigerant from the binary side from the compressor is transferred to the primary side. The refrigerant on the primary side in the evaporator is passed through a flow path that is separate from the heat exchanger tube through which it passes, and heat (heat of condensation) is applied to the frost that has formed and adhered to the outer surface of the heat exchanger tube to melt it, and the high-pressure gas on the secondary side is passed through. The refrigerant is made into a high-pressure liquid refrigerant on the binary side and is led to the defrost heat exchanger via the defrost expansion valve, and is then introduced as a low-pressure refrigerant gas on the binary side from a branch pipe installed in the suction pipe of the binary side compressor. It is designed to be sucked into a compressor.

[Operation] The high-pressure gas refrigerant on the binary side compressed by the binary side compressor is passed from the branch pipe of the compressor discharge pipe through a flow path separate from the heat transfer tube through which the primary side refrigerant of the primary side evaporator passes. , the frost adhering to the outer surface of the primary side refrigerant heat transfer tube is given approximately 3 to 4 times the amount of heat of condensation as the heat equivalent to the shaft power of the secondary side compressor, and the frost is melted and removed in a short time. It becomes possible to carry out frost.

In addition, the high-pressure liquid refrigerant on the binary side condensed in the flow path of the primary side evaporator is depressurized by the defrost expansion valve to become the low-pressure liquid refrigerant on the binary side. Evaporate the liquid refrigerant and return it to the suction pipe of the dual-side compressor as a low-pressure gas refrigerant to enable recirculation, thereby securing a heat source for defrosting operation of the primary-side evaporator from the dual-side compressor. I can do it.

〔Example〕

Reference will now be made in detail to the accompanying drawings, which illustrate embodiments of the invention.

Reference numeral 1 designates a single-side evaporator, which is provided with a single-side refrigerant heat transfer tube 2 for passing the single-side refrigerant therein, and is placed inside an ultra-low temperature refrigerator 3 surrounded by a heat insulating wall 4. A fan 5 is attached to circulate the water into the primary side evaporator 1. Reference numeral 6 denotes a single-side compressor, in which a suction pipe 6a is connected to one end of the single-side refrigerant heat transfer tube 2 of the evaporator 1;
A one-source refrigerant is passed through the pipe 2, and the one-source low-pressure gas refrigerant that has been evaporated by removing the heat of vaporization from the air inside the refrigerator 3 is sucked and compressed.

Reference numeral 7 designates a one-side condenser (cascade condenser), in which a one-side refrigerant heat exchanger tube 8 through which the one-side high-pressure gas refrigerant compressed by the one-side compressor 6 passes is disposed, and one end of the heat exchanger tube 8 and The discharge pipe 6b of the primary side compressor 6 is connected to the primary side compressor 6, and the binary side refrigerant is introduced around the heat exchanger tube 8 in the condenser 7 to be evaporated, and the primary side refrigerant is passed through the heat exchanger tube 8. It absorbs condensation heat from the side high-pressure gas refrigerant and condenses (liquefies) it to form a single-side high-pressure liquid refrigerant. Reference numeral 9 denotes a primary side liquid receiver, which is connected to the other end of the heat exchanger tube 8, and is connected to the other end of the primary side condenser 7.
It receives and stores the high-pressure liquid refrigerant on the single side that has been liquefied inside.

Reference numeral 10 denotes a single side expansion valve, which is attached to a pipe 11 connecting the outlet of the liquid receiver 9 and the other end of the single side refrigerant heat transfer tube 2;
The primary side high-pressure liquid refrigerant from the liquid receiver 9 is expanded and made to flow into the heat exchanger tube 2 of the primary side evaporator 1. Reference numeral 12 denotes a refrigerant pipe on the primary side, which includes heat transfer tubes 2 of the evaporator l on the primary side,
Compressor 6, heat transfer tube 8 of condenser 7, liquid receiver 9, and expansion valve 1
0 to the heat transfer tube 2, and the conduit 12
This is to circulate a single-side refrigerant inside the tank. Reference numeral 13 denotes a binary side compressor, in which a suction pipe 13a is connected to an upper outlet pipe 7b of the single side condenser 7, and a low pressure liquid refrigerant on the binary side from a lower inlet pipe 7a, which will be described later, and a heat exchanger tube of the condenser 7 are connected. The refrigerant is heat exchanged with the high-pressure gas refrigerant on the primary side passing through the refrigerant 8, and the evaporated low-pressure gas refrigerant on the binary side is sucked and compressed.

14 is a binary side condenser, and the discharge pipe 13 of the binary side compressor 13
b and its inlet pipe 14a are connected, and as shown in FIG. The refrigerant is introduced through the inlet pipe 14a, exchanges heat with air, water, etc. passing through the heat transfer tube 15, and absorbs condensation heat with the air, water, etc., to form a binary high-pressure liquid refrigerant.

Reference numeral 16 denotes a binary side expansion valve, which is interposed between the outlet pipe 14b of the condenser 14 and the lower inlet pipe 7a of the single side condenser 7, and is located on the binary side from the outlet pipe 14b of the condenser 14. The single-side condenser 7 expands the high-pressure liquid refrigerant and converts it into a dual-side low-pressure liquid refrigerant.
It is intended to cause an inflow into the country. 17 is a liquid level control device such as a float valve attached to the upper part of the single-side condenser 7, and when the low-pressure liquid refrigerant on the dual-side side in the condenser 7 reaches a certain level, the dual-side expansion valve 16 is activated. It is equipped to block it. 18
is a binary side refrigerant pipe line, which runs from the inlet pipe 7a to the outlet pipe 7b of the single side condenser 7, and the compressor 13 on the binary side,
A series of refrigerants return to the inlet pipe 7a of the condenser 7 via the condenser 14 and the expansion valve 16, and circulate the dual-side refrigerant within the conduit 18. Reference numeral 19 denotes a binary refrigerating machine (cascade type refrigeration system) which is composed of a primary side refrigerant pipe 12 and a secondary side refrigerant pipe 18, and uses the primary side condenser (cascade condenser) 7 as an evaporator for the secondary side refrigerant. , 20 is a discharge three-way valve, which is connected to the discharge pipe 13b of the two-way compressor 13 through its two-way opening, and branches off the remaining auspicious day 20a, and 21 is a discharge three-way valve that These are connected branch pipes. Reference numeral 22 denotes a dual-side refrigerant heat exchanger tube disposed within the primary-side evaporator 1, which exchanges heat with the primary-side refrigerant heat exchanger tube 2. One end of the tube is connected to the tip of the branch pipe 21, and is discharged during the defrosting process. Switch the three-way valve 20 to the Ichiyoshihichi 20a side, and open the discharge three-way valve 2.
The binary side high pressure gas refrigerant from the binary side compressor 13 is passed through the branch pipe 21 via the single auspicious day 20a of The condenser heat amount is approximately 3 to 4 times the shaft power of No. 13, and is used to defrost the frost. 23 is a defrost heat exchanger provided separately from the binary side condenser 14 as shown in FIG.
A heat transfer tube 24 through which air, water, etc. passes is attached, and one end of the heat transfer tube 24 is connected to the other end of the dual-side refrigerant heat transfer tube 22 through a tube 26 with a defrost expansion valve 25 interposed therebetween. The high-pressure liquid refrigerant on the binary side, which has been liquefied by removing condensation heat for defrosting, is expanded and depressurized by the defrost expansion valve 25 and introduced as low-pressure liquid refrigerant on the binary side, and the air passing through the heat transfer tubes 24 is Alternatively, the heat of vaporization is obtained from water or the like and used as a binary low pressure gas refrigerant. Reference numeral 27 denotes a suction three-way valve, whose two-way port is interposed and connected to the suction pipe 13a of the two-way compressor 13, and the remaining one side valve 27a is branched, and the auspicious day 27a is connected to the suction pipe 13a of the two-way compressor 13.
is connected to the other end of the defrosting heat exchanger 23 via a branch pipe 28, and the suction three-way valve 27 is connected to the
The low-pressure gas refrigerant on the binary side evaporated in the heat exchanger 23 is returned to the compressor 13 on the binary side.

Furthermore, FIGS. 2 and 3 show an embodiment of a dual-side condenser and defrost heat exchanger 29 that integrates the dual-side condenser 14 and the defrost heat exchanger 23 shown in FIG. , second
The figure shows a fan 30 provided on the outer surface to make the dual-side condenser 14 of FIG. 25 and the suction three-way valve 27.
The tube ends of 6 and 28 are connected to the heat exchanger tube 31 in the binary side condenser 14 by a separate heat exchanger tube 32, and the binary side high pressure gas refrigerant from the binary side compressor 13 is transferred into the heat exchanger tube 31. It exchanges heat with the air from the fan 30, removes condensation heat, and converts the binary high pressure gas refrigerant into a binary high pressure liquid refrigerant in the heat transfer tube 31, while the discharge three-way valve is used during the defrosting process. 2
From the auspicious day 20a of 0, the frost adhering to the outer surface of the single-side refrigerant heat exchanger tube 2 is defrosted in the same manner as described above by the high-pressure gas refrigerant on the dual-side side passing through the inside of the dual-side refrigerant heat exchanger tube 22 of the single-side evaporator l. The high-pressure gas refrigerant on the binary side that has lost condensation heat to the frost is made into a high-pressure liquid refrigerant on the binary side, and the low-pressure liquid refrigerant on the binary side expanded and depressurized by the defrosting expansion valve 25 is made to flow through the heat transfer tube 32. Heat of vaporization is removed from the air heated by the heat of condensation from the fan 30, and the binary side low pressure liquid refrigerant is evaporated within the heat transfer tube 32 to become a binary side low pressure gas refrigerant.

In FIG. 3, a heat transfer tube 33 for passing water is provided inside like the heat transfer tube 15, so that the binary side condenser 14 in FIG. The tube ends of the tubes 26 and 28 are connected by a heat transfer tube 32 in the same manner as shown in FIG. The explanation can be made in the same manner as in FIG. 2 except that the process is carried out in the binary side condenser/defrost heat exchanger 29.

Furthermore, FIGS. 4 and 5 show another embodiment of the single-side evaporator 1, which is in claim 3, in which reference numeral 34 denotes a single-side refrigerant heat transfer tube, in which a dual-side refrigerant tube is arranged concentrically. The refrigerant heat transfer tube 35 is made double by forming a large number of inner fins 36 radially between both heat transfer tubes 34 and 35 to form a double fin tube 37. Both heat transfer tubes 34 and 35 and each inner fin 36 A large number of spaces surrounded by the above are defined as a single-side refrigerant flow path 38, and the inside of the dual-side refrigerant heat transfer tube 35 is designated as a dual-side refrigerant flow path 39.

Reference numeral 40 denotes a large number of outer fins, which are fixed to the casing 41 in multiple rows and stages, and are inserted into and fixed to the single refrigerant heat transfer tube 34 outside each double fin tube 37. . Reference numeral 42 denotes a cover attached to both ends of each double fin tube 37, one end of which is inserted into the outer periphery of the single-side refrigerant heat transfer tube 34, and the other end is a cover attached to the dual-side refrigerant transfer tube that protrudes from both sides of the single-side refrigerant heat transfer tube 34. The dual-side refrigerant heat transfer tubes 35. which are inserted into the outer periphery of the heat tube 35 and have a connecting port 43 protruding from the side surface of the body, protrude on both sides of each double fin tube 37.37 adjacent to each other in multiple stages in the vertical direction. 35 are alternately connected by U-bends 44, and in the same way, adjacent alternate connection ports 43, 43 are connected by connecting pipes 45, and a refrigerant flow path 38 and a dual-side refrigerant flow are provided on the one side of each double fin pipe 37. The route 39 is a series. 46 is the primary side refrigerant inlet, and the connection port 43 at the upper end of the primary side refrigerant flow path 3rd
47 is a single side refrigerant outlet, and 47 is an opening of the refrigerant flow path 3.
This is the opening of the connection port 43 at the lower end of 8. 48 is a binary side refrigerant inlet, which is an opening of the binary side refrigerant heat transfer tube 35 at the upper end of the binary side refrigerant flow path 39; 49 is a binary side refrigerant outlet, which is the opening of the binary side refrigerant heat transfer tube 35 at the lower end of the refrigerant flow path 39; This is the opening of the heat pipe 35. Also, the single side refrigerant person, exit 46, 47 and the dual side refrigerant person, exit 4
8.49 is individually equipped with a distributor, a header, etc. (not shown), and the single-side and dual-side refrigerant flows into the multi-row single-side and dual-side refrigerant channels 38.39, It is something that flows out. 50.50 is an air inlet provided below the casing 41 of the primary side evaporator 1; 51 is an air outlet provided at the upper part of the casing 41;
A fan 52 is attached to the. Reference numeral 53 denotes a drain pan, which is attached to the lower surface of the casing 41 and receives water when the frost adhering to the outer surface of the single-side refrigerant heat transfer tube 34 melts during the defrosting process. This is a drain hole for discharging water. Furthermore, it is also possible to provide the dual-side refrigerant flow path 39 closest to the outside of the single-side refrigerant heat transfer tube 34, penetrating the outer fins 40, and remove frost from the outer fins 40 by heat conduction.

By employing the double fin tube 37 in the single-side evaporator 1 in this way, the wetted area of the single-side refrigerant flow path 38 is increased, heat transfer is improved, and the single-side refrigerant heat transfer tube 34 can be shortened. It becomes possible to reduce the cross-sectional area of the heat exchanger tube,
The amount of refrigerant used can be significantly reduced, making it possible to lower costs.

〔Effect of the invention〕

The present invention has the above configuration, in which a dual refrigerant heat transfer tube 22 having a flow path separate from the primary refrigerant heat transfer tube 2 is separately installed in the primary evaporator 1, and the discharge of the dual compressor 13 is controlled. A discharge three-way valve 20 is attached to the pipe 13b to branch off the one-auspicious day 20a, which leads to the two-way side heat exchanger tube 22 of the one-way side evaporator 1 through the branch pipe 21, and the two-way side refrigerant heat exchanger tube 22 The high-pressure liquid refrigerant on the binary side condensed in the refrigerant is reduced in pressure by the defrost expansion valve 25 through the pipe 26, and guided to the defrost heat exchanger 23 or the binary side condenser/defrost heat exchanger 29, where air or It is evaporated by exchanging heat with water, etc., and then passed through one side 27a of the suction three-way valve 27 attached to the suction pipe 13a of the dual-side compressor 13, and then returned to the dual-side compressor 13. Since the defrost heat source can be maintained at all times during the defrosting process.

Also, during the defrosting process, the dual side refrigerant heat transfer tube 2 of the primary side evaporator 1
The binary side high-pressure gas refrigerant from the binary side compressor 13 guided to the secondary side compressor 13 attaches to the outer surface of the primary side refrigerant heat transfer tube 2 with an amount of condensation heat that is approximately 3 to 4 times the shaft power of the binary side compressor 13. give it to frost,
Since the frost can be thawed and defrosted in a short period of time, other equipment such as electric heaters and low-temperature brine is not required, reducing equipment costs, avoiding the hassle of managing these items, and reducing maintenance costs. This makes it easier to operate, and the energy required for these operations can be saved, making it possible to save energy.

[Brief explanation of the drawing]

The attached drawings show embodiments of the present invention. Figure 1 is a schematic circuit diagram of a binary refrigerator of the present invention, and Figures 2 and 3 show a binary side condenser and a defrost heat exchanger. Figure 2 is an air-cooled type, Figure 3 is a water-cooled type, and Figures 4 and 5 are other embodiments of the single-side evaporator. Fig. 4 is a schematic front view of the casing in cross section, and Fig. 5 is a schematic diagram of the double fin tube. It is a vertical cross-sectional view rotated by 90 degrees. ■... Primary side evaporator, 2-11 Primary side refrigerant heat transfer tube, 3
---Ultra-low temperature refrigerator, 4-insulation wall, 5--fan, 6
... Single side compressor, 6a- Suction pipe, 6b- Discharge pipe, 7- Single side condenser, 7a- Lower inlet pipe, 7b-.
・Upper outlet pipe, 8-11 primary side refrigerant heat transfer tube, 9-11 primary side liquid receiver, 10-11 primary side expansion valve, 11-pipe, 12
--- Single side refrigerant pipe line, 13- Binary side compressor, 13a-
...-suction pipe, 13b--discharge pipe, 14--binary side condenser, 14 a--inlet pipe, 14 b--outlet pipe, 15
- = heat transfer tube, 16 - binary side expansion valve, 17 - liquid level control device, 18 - binary refrigerant pipeline, 19 - binary refrigerator, 20 - discharge three-way valve, 20 a--- one port, 21-branch pipe, 22
- - Binary side refrigerant heat exchanger tube, 23 - Defrost heat exchanger, 24 - Heat exchanger tube, 25 - Defrost expansion valve, 2
6--Pipe, 27-Suction three-way valve, 27a--One port, 2
8--branch pipe, 29-binary side condenser and defrost heat exchanger, 30--fan, 31, 32. 33-heat exchanger tube, 34...-primary side refrigerant heat exchanger tube, 35--binary side refrigerant heat exchanger tube, 36--inner fin, 37--double fin tube, 38-11-primary side refrigerant flow Channel, 39--Two-way refrigerant flow path, 40-Outer fin, 41--Casing, 42--Cover, 43- Connection port, 44-U bend, 45 Series connection pipe, 46--One side Refrigerant inlet, 47-
・Single side refrigerant outlet, 48-・-Dual side refrigerant inlet, 49-
... Binary side refrigerant outlet, 50... Air inlet, 51-...
Air outlet, 52-fan, 53- drain pan, 54
−・−Drain hole. Procedural amendment 1. Indication of the case Patent application No. 126355 λ of 1988 Title of the invention Defrosting method and device 3 for a binary refrigerator, person making the amendment Relationship with the case Patent applicant address 3-2-4 Nakanoshima, Kita-ku, Osaka Issue name
Nichishin Gyogyo Co., Ltd. Representative Director Seigo Kotane 4, Agent Address 2-8-1-6 Nishitenma, Kita-ku, Osaka Subject of amendment Column 7 for detailed explanation of the invention in the specification, Contents of amendment ■, page 3 of the detailed specification, 1 yen.

Claims (1)

[Claims] 1. In a binary refrigerator that evaporates a binary refrigerant in order to condense the primary refrigerant in the primary condenser, the removal of the primary evaporator using a high-pressure gas refrigerant on the binary side A defrosting method in a binary refrigerator characterized by performing frosting. 2. A pipe line in which the primary side refrigerant circulates through the primary side compressor, condenser, expansion valve, and evaporator in this order and returns to the primary side compressor again, and a secondary pipe that condenses the primary side refrigerant through the primary side condenser. An evaporator for the primary refrigerant, and a pipeline in which the secondary refrigerant circulates from the primary condenser to the compressor, condenser, and expansion valve on the secondary side in this order, and returns to the primary condenser again. In the former refrigerator, the tip of the branch pipe from the discharge pipe of the dual-side compressor is connected to a separate circuit with the primary-side refrigerant passing through the primary-side evaporator, and the defrost expansion valve is connected to the other end of the circuit. 1. A defrosting device for a binary refrigerator, characterized in that the defrosting heat exchanger is connected to a branch pipe from a suction pipe of a binary compressor. 3. The binary refrigerating machine according to claim 2, wherein a flow path through which the primary refrigerant passes and a flow path through which the secondary refrigerant passes are separately provided in the heat transfer tube of the primary evaporator. Defrost device. 4. Claim 2, characterized in that the binary side condenser is air-cooled, the condenser and the defrost heat exchanger are combined, and the heat source of the defrost heat exchanger and the condenser is the same. Or the defrost device in the binary refrigerator according to 3. 5. Claim 2 or 5, characterized in that the binary side condenser is water-cooled, the condenser and a defrost heat exchanger are combined, and the binary side refrigerant liquid is used as a heat source for the defrost heat exchanger. 3. The defrost device in the secondary refrigerator according to 3. 6. The defrosting device for a binary refrigerator according to claim 2 or 3, further comprising a separate defrosting heat exchanger using air, water, or the like as a heat source.