JPH03241277A - Method and apparatus for defrosting using liquid refrigerant pump for dry vaporizer - Google Patents

Abstract

PURPOSE:To improve defrosting efficiency by forming a defrosting liquid refrigerant circulation piping between a liquid refrigerant heating coil and a dry vaporizer and providing in an intake pipe an automatic open/close valve which closes during defrosting operation. CONSTITUTION:Part of liquid refrigerant in a liquid reservoir 9 is made to pass through a liquid refrigerant heating coil 10 to be hot liquid refrigerant, and let it flow into a vaporizer 12, in which sensible heat of the hot liquid refrigerant defrosts the vaporizer 12. Successively, the liquid refrigerant having radiated defrosting heat is taken out of the vaporizer 12 by a liquid refrigerant pump 5, and then made to pass again through the liquid refrigerant heating coil 10 to be hot liquid refrigerant, which is circulated by the liquid refrigerant pump 5 between inside of the vaporizer 12 and the liquid refrigerant heating coil 10 until defrosting operation is finished. At this time, an automatic open/ close valve 1 provided in an intake pipe closes for preventing the liquid refriger ant which has defrosted from being taken in by a compressor. Thus, a vaporizer of high defrosting efficiency can be obtained.

Description

Detailed Description of the Invention 10 Objects of the Invention (Industrial Application Field) The present invention relates to refrigeration, refrigerators and refrigeration using a dry evaporator,
A defrosting method and defrosting device for a refrigerated open showcase that minimizes the rise in internal temperature during defrosting and keeps the internal temperature at an appropriate and constant level in a short time. Regarding.

(Prior art) Conventionally, there is a defrosting method using a liquid refrigerant pump and a defrosting device for a flooded evaporator, but there is a defrosting method using a liquid refrigerant pump for defrosting a dry type evaporator. There is no frost method and equipment. Conventionally, there are methods and devices for defrosting dry evaporators (hereinafter referred to as evaporators) using hot gas.
Various devices are commercially available.

There are also devices that defrost using liquid refrigerant.

(For example, see Japanese Patent Application Publication No. 63-290380.) (Problems to be Solved by the Invention) In the conventional method of defrosting by discharging hot gas into the evaporator, the hot gas condenses and liquefies and There are many problems that remain. When the condensate refrigerant remains in the evaporator,
During defrosting, a portion of the gas re-evaporates due to the suction action of the compressor, absorbs latent heat of vaporization, and performs a cooling action, which inhibits defrosting and takes a long time to defrost.Therefore, the hot gas defrosting heat is transferred from the evaporator to the storage room. It spreads inside the warehouse, raising the temperature inside the warehouse and accelerating discoloration and deterioration of stored products. Further, the condensed liquid refrigerant is sucked into the compressor and returns to the compressor in the form of liquid refrigerant, causing a liquid hammer phenomenon, which may damage the compressor. It is difficult to regenerate hot gas even if the compressor draws the low-temperature condensate refrigerant in its original state.
We are dealing with this problem using various hot gas regeneration devices. Many types of hot gas regeneration equipment are used, such as a simple hot gas type, sequential hot gas type, and hot gas heat storage reevaporation type.The simple hot gas type is the simplest and most economical type, but the compressor If the evaporator is located far away, has multiple units, or is used in a large evaporator, the refrigerant in the refrigeration cycle may stay in the evaporator and regenerate hot gas. Sometimes it is not possible. Also, it tends to cause liquid back-up, and there is a high risk of compressor damage. Sequential hot gas type uses multiple evaporators and has the advantage of being able to perform defrosting and cooling alternately, which has the advantage of maintaining an appropriate temperature inside the refrigerator, but it is used to defrost the evaporators inside the refrigerator in the low temperature range. This increases the defrosting time and requires many automatic on-off valves and control devices. When defrosting is performed using a hot gas heat storage re-evaporation device, the compressor operates at a low load during seasons such as winter when the outside temperature is low, and if the operation time is short, the amount of heat storage becomes insufficient and hot gas is not generated again. Since it is difficult to perform this method, external heating such as an electric heater is required, which is not energy-saving. In the conventional method of using liquid refrigerant for defrosting, the temperature of the liquid refrigerant is increased by increasing the temperature of the discharged gas. Since the desired high temperature cannot be obtained, the medium temperature range (approximately 0℃
It is used to defrost the evaporator inside the refrigerator (internal temperature of -5℃ to 15℃), but it is used to defrost the evaporator in the refrigerator with low temperature (interior temperature of -5℃ or lower). It is unsuitable, has limitations in use, and requires many automatic on-off valves and complex control equipment. The present invention was developed in order to eliminate the problems of conventional hot gas defrosting and liquid refrigerant defrosting as described above, and is simple and reliable, consumes less power, and is less likely to malfunction. A defrosting method and defrosting method for a dry evaporator that is easy to maintain, completes defrosting in a short time, minimizes the rise in internal temperature during defrosting, and delays quality deterioration of stored products as much as possible. The purpose is to provide equipment.

B. Structure of the Invention (Means for Solving the Problems) The evaporator defrosting method and defrosting device according to the first and second claims of the present invention are capable of defrosting a liquid receiving liquid without using hot gas. A part of the liquid refrigerant in the container is passed through a liquid refrigerant heating coil to become hot liquid refrigerant, which is then flowed into the evaporator, and the evaporator is defrosted using the sensible heat of the hot liquid refrigerant.

Next, the defrosted clean liquid refrigerant after releasing the defrosting heat is sucked out of the evaporator using a liquid refrigerant pump, and passed through the liquid refrigerant heating coil again to become hot liquid refrigerant, where it evaporates until the end of defrosting. A liquid refrigerant pump is used to circulate the liquid refrigerant between the inside of the container and the liquid refrigerant heating coil, and an automatic opening/closing valve provided in the suction pipe is closed to prevent the defrosting liquid refrigerant from being sucked into the compressor. The evaporator defrosting method and defrosting device according to the third and fourth claims of the present invention use hot gas for defrosting, close an automatic opening/closing valve provided in the suction pipe, and A part of the liquid refrigerant is passed through a liquid refrigerant heating coil to become hot liquid refrigerant, and a hot liquid refrigerant spray chamber is installed in a part of the suction pipe of the inlet side pipe of the gas-liquid separator to spray it into the suction pipe. It is used as a refrigerant for hot gas regeneration. The hot gas that has flowed into the evaporator is sucked from the inside of the container, combined with the liquid refrigerant supplied from the liquid receiver described above, and passed through a liquid refrigerant heating coil to become hot liquid refrigerant.
The hot liquid refrigerant is sprayed into the spray chamber.

(Function) When defrosting is performed using the defrosting method and defrosting device according to the first and second claims of the present invention, the automatic opening/closing valve of the suction pipe (hereinafter abbreviated as suction valve) is closed to receive liquid. The compressor heats the liquid refrigerant supplied from the container to become hot liquid refrigerant, circulates it between the evaporator and the liquid refrigerant heating coil, and returns to the receiver after defrosting. Since fresh liquid refrigerant is not sucked, the compressor is not damaged by liquid hammer, and there is no need to reevaporate the defrosting fresh liquid refrigerant. When defrosting is performed using the defrosting method and defrosting device of the third and fourth inventions, since hot gas is used, defrosting is quickly performed, and the condensed liquid refrigerant is removed by the liquid refrigerant pump. Since the refrigerant is transferred outside without being retained in the evaporator, defrosting ends quickly, and since defrosting is performed with the suction valve closed, the compressor does not suck in condensed refrigerant. Therefore,
The compressor will not be damaged by the liquid hammer, and by spraying the hot liquid refrigerant into a small hot liquid refrigerant spray chamber,
Since hot gas can be regenerated, hot gas can be regenerated even without a large hot gas heat storage and reevaporation device.

(Example) An example of the present invention will be described below based on the drawings. FIG. 1 shows the configuration of a defrosting method and apparatus using a liquid refrigerant pump for a dry evaporator according to the first and second aspects of the invention. During the cooling operation, the suction valve (1) and the liquid valve (2) are open, so the compressor (8) is operating. Defrost control device (7
), the liquid valve (2) closes and the expansion valve (2) closes.
1) The supply of liquid refrigerant to 1) is stopped. Then the suction valve (1)
is closed and the compressor (8) is stopped. The defrosting liquid refrigerant circulation valve (6) opens, and then the liquid pipe (2) on the outlet side of the liquid receiver (9) opens.
The liquid receiver liquid supply valve (3) installed in the liquid receiver liquid supply pipe (25), which is provided by branching off a part of 4), is opened only for a certain period of time, and the liquid in the liquid receiver (9) is A part of the liquid refrigerant is closed after the amount of circulating liquid refrigerant for defrosting required for defrosting is supplied.

The supplied circulating liquid refrigerant for defrosting is transferred to the receiver liquid supply pipe (25
) A liquid refrigerant circulation valve for defrosting (6) provided in a liquid refrigerant circulation pipe for defrosting (11) connected to a three-branch part (26) provided at the tip of the liquid refrigerant circulation valve for defrosting (11)
), it is heated while passing through the liquid refrigerant heating coil (10), becomes hot liquid refrigerant, and becomes a liquid refrigerant circulation pipe for defrosting (11).
The hot liquid refrigerant flows into the evaporator (12) through the hot liquid refrigerant inlet pipe (13) which is branched and connected to the inlet pipe of the evaporator (12) at the outlet pipe of the expansion valve (21). The inflowing hot liquid refrigerant emits sensible heat and flows down while defrosting the evaporator (12), becoming a low-temperature defrosted clear liquid refrigerant, and the defrosted liquid refrigerant is branched and connected to the evaporator outlet pipe (27). From the refrigerant extraction pipe (20), it passes through the defrost liquid valve (4) installed in the pipe, and then the liquid refrigerant pump (5)
The liquid refrigerant is sucked by the operation of the liquid refrigerant, passes through the three-branch part (26) to which the outlet side pipe of the liquid refrigerant pump (5) is connected, passes through the defrosting liquid refrigerant circulation pipe (11), and enters the liquid refrigerant heating coil (10). The liquid refrigerant is heated and becomes a hot liquid refrigerant, and the liquid refrigerant pump (5) is operated between the evaporator (12) and the liquid refrigerant heating coil (10), and the liquid refrigerant circulates in the defrosting liquid refrigerant circulation pipe (11) at the end of defrosting. defrost by circulating until When defrosting is finished, the defrost control device (
7) or by the operation of the defrosting end temperature regulator (18). The receiver liquid return valve (19) opens, the defrosting liquid refrigerant circulation valve (6) closes, and the supply of hot liquid refrigerant to the evaporator (12) is stopped. The defrosting fresh liquid refrigerant is returned into the receiver (9) through the receiver liquid return valve (19). The defrosted liquid valve (4) and the liquid refrigerant pump (5) close, the suction valve (1) and the liquid valve (2) open, and the liquid refrigerant is supplied to the expansion valve (21) and the compressor (8). is operated and cooling operation is started. Check valves (22) are provided at necessary locations in each pipe. The liquid temperature of the hot liquid refrigerant is set by a heat storage temperature controller (16) that detects the heat storage liquid temperature in the hot gas heat storage tank (15) that stores the discharge gas temperature during cooling operation of the compressor (8).
The hot gas bypass valve (17) provided between the discharge pipe (33) and the condenser (14) is adjusted by opening and closing. This determines the temperature of the liquid refrigerant passing through the liquid refrigerant heating coil (10) built in the hot gas heat storage tank (15). FIG. 2 shows the configuration of a defrosting method and a defrosting device using a liquid refrigerant pump for a dry evaporator according to the third and fourth aspects of the present invention. During cooling operation, the suction pipe (23
) and the liquid valve (2) provided in the liquid pipe (24) are open and the compressor (8) is operating.

Due to the defrosting operation of the defrosting control device (7), the liquid valve (2) closes and the supply of liquid refrigerant to the expansion valve (21) is stopped. The suction valve (1) is then closed and the compressor (8) no longer draws refrigerant directly from the evaporator (12). Open the receiver liquid supply valve (3) in the receiver liquid supply pipe (25) provided by branching off a part of the liquid pipe (24) on the outlet side of the receiver (9), and open the receiver liquid supply valve (3). (
The inflow amount of some of the liquid refrigerant in 9) is adjusted by the supply liquid amount control valve (29), and the liquid refrigerant is passed through the suction and discharge pipe (30) connected to the three-branch portion (26), and then the liquid refrigerant is heated to the liquid refrigerant heating coil (10). The hot liquid refrigerant is heated and becomes a hot liquid refrigerant, and is sprayed into the hot liquid refrigerant spray chamber (32) provided in the suction pipe (23) on the inlet side of the gas-liquid separator (31) to become a high-temperature, low-pressure gas and compressed. machine (8
) continues to operate, sucking in and generating hot gas. The hot gas passes through a hot gas valve (35) installed in a hot gas pipe (34) branched from the discharge pipe (33) of the compressor (8), and is evaporated at the outlet pipe of the expansion valve (21). vessel(
12) Hot gas inflow pipe (
36) into the evaporator (12). The inflowing hot gas performs defrosting by releasing latent heat of condensation, becomes a condensed liquid refrigerant, and is transferred from the defrosted liquid refrigerant extraction pipe (20) connected to the evaporator outlet pipe (27) by branching off to the defrosted liquid valve ( 4), is sucked in by the operation of the liquid refrigerant pump (5), and is sucked in by the operation of the liquid refrigerant pump (5).
The liquid refrigerant passes through the three-branch part (26) connected to the outlet pipe of 5), passes through the spray liquid volume control valve (37) in the suction/discharge pipe (30), and is heated in the liquid refrigerant heating coil (10) to become hot. It becomes a liquid refrigerant and is sprayed into the hot liquid refrigerant spray chamber (32),
This process is repeated until defrosting is completed. The liquid refrigerant supplied from the liquid receiver (9) and the defrosted condensed liquid refrigerant are sucked and discharged by the liquid refrigerant pump (5), and are combined at the three-branch portion (26) to adjust the amount of sprayed liquid. If there is a large amount of defrosted condensate refrigerant returned by adjusting the valve (37), it will return to the liquid receiver (9) from the three-branch part (26), and if there is a shortage, it will return to the liquid receiver (9). Supplied from. The defrosting is completed by operating either the defrosting control device (7) or the defrosting end temperature regulator (18), closing the hot gas valve (35) and receiver liquid supply valve (3), After stopping the supply of hot gas and liquid refrigerant and spraying all of the defrosted condensed liquid refrigerant in the evaporator (12) into the hot liquid refrigerant spray chamber (32), the defrosted liquid valve (4) is opened. The liquid refrigerant pump (5) is closed, the liquid refrigerant pump (5) is stopped, the liquid valve (2) is opened, the liquid refrigerant is supplied to the expansion valve (21), and the suction valve (1) is opened to supply the refrigerant to the compressor (8). It is sucked into cooling operation. Check valves (22) are provided at necessary locations in each pipe. To set the liquid temperature of hot liquid refrigerant,
The discharge pipe (33) and the condenser (14) are controlled by the heat storage temperature controller (16) that detects the heat storage temperature in the hot gas heat storage tank (15) that stores the heat of discharged gas during cooling operation of the compressor (8). ) Adjust by opening and closing the hot gas bypass valve (17) provided in between. This determines the temperature of the liquid refrigerant passing through the liquid refrigerant heating coil (10) built in the hot gas heat storage tank (15).

C. Effects of the Invention The defrosting method and defrosting device according to the first and second claims of the present invention use a heated hot liquid refrigerant as the defrosting refrigerant. Hot liquid refrigerant has a higher heat capacity and higher thermal conductivity than hot gas, so it has higher defrosting efficiency than hot gas. Also, while the temperature of hot liquid refrigerant can be controlled, it is difficult to control the temperature of hot gas. Medium temperature range (approximately 0℃ to 15℃ internal temperature)
The products stored in refrigerators and refrigerated open cases are mainly meat, fresh fish, processed foods, etc., and the greatest fear is an increase in internal temperature, which accelerates discoloration and quality deterioration. Therefore, it is desirable to maintain the temperature inside the refrigerator at an appropriate temperature during cooling and defrosting, and when adjusting the defrosting time, the evaporator (
12) maintains a thin box state, so the defrosting time is significantly shortened, and therefore, the diffusion of defrosting heat into the refrigerator from the evaporator (12) is minimized, which is effective in maintaining the temperature inside the refrigerator at an appropriate temperature. The defrosting method and defrosting device of the present invention are particularly suitable for defrosting an evaporator for storage where the internal temperature is in the medium temperature range. Since the piping for transferring the hot liquid refrigerant can be a small-diameter pipe, most of the liquid refrigerant circulation pipe (11) for defrosting is a liquid pipe, and compared to hot gas, the degree of expansion and contraction of the piping is less, and damage to the piping is reduced. There is also less loosening of the tightening screws of mounting valves and mounting valves due to temperature changes, and there are fewer failures due to refrigerant leaks. Since defrosting is performed by closing the suction valve, the compressor does not suck in the defrosted clean liquid refrigerant in the evaporator, so there is no risk of liquid bank formation and damage to the compressor. Therefore, there is no need for liquid back protection equipment. Since there is no need to regenerate hot gas, a hot gas regeneration device is also unnecessary.

Since the refrigerating machine oil that adheres or remains in the evaporator is transferred to the outside of the evaporator by the liquid refrigerant pump every time defrosting is performed, the heat exchange efficiency of the evaporator during cooling operation is improved. During defrosting, the compressor is stopped and a small horsepower liquid refrigerant pump is operated to defrost, so the power consumption for defrosting is low and the life of the compressor is extended. In conventional defrosting equipment using liquid refrigerant, one evaporator is filled with liquid refrigerant whose temperature is not so high, and only the amount supplied to the expansion valve of the other evaporator is transferred to the liquid refrigerant. Since the moving speed of the liquid refrigerant in the evaporator is only 1, and the defrosting is performed using the sensible heat of the liquid refrigerant, the defrosting time is long and the defrosting efficiency is poor. Therefore, it is not suitable for defrosting an evaporator where the internal temperature is in the low temperature range. In the defrosting method and defrosting device of the present invention, the temperature of the hot liquid refrigerant for defrosting can be adjusted from low to high temperature, so it can be used when the outside temperature is low and for defrosting the evaporator when the internal temperature is in the low range. Since the hot liquid refrigerant for defrosting is rapidly circulated in the evaporator by the liquid refrigerant pump, the defrosting time is significantly shortened and the defrosting efficiency is high. To defrost an evaporator with a low internal temperature in severe winters or extremely cold regions, instead of using hot gas heat storage to heat the liquid refrigerant heating coil, use another heat source, such as an oil water heater, to defrost the evaporator. When used, it is possible to defrost any evaporator whose internal temperature is in the low range. Since the defrosting method and defrosting device according to the third and fourth inventions use hot gas for defrosting, the defrosting method and the defrosting device according to the third and fourth inventions use hot gas for defrosting.
Suitable for defrosting an evaporator with an internal temperature of . In conventional hot gas defrosting, the condensed refrigerant after hot gas defrost stays in the evaporator, resulting in long defrosting times, liquid backlog in the compressor, and reevaporation of the mother suction refrigerant. The problem of having to deal with it is not possible in the case of the present invention. Since the liquid refrigerant pump quickly transfers the condensed refrigerant to the outside of the evaporator, the defrosting time is significantly shortened, and the suction valve is closed during defrosting, so the compressor does not directly suck in the low-temperature condensed refrigerant. Therefore, there is no problem of liquid back up. Since the defrosting time is short, the time for the defrosting heat from the evaporator to diffuse into the refrigerator is short, so the rise in temperature inside the refrigerator is kept to a minimum and the deterioration of the quality of stored products is delayed. When the condensed liquid refrigerant is heated to become hot liquid refrigerant and sprayed into the hot liquid refrigerant spray chamber provided in the suction pipe, the hot liquid refrigerant becomes a high temperature and low pressure gas refrigerant, and the compressor sucks the conventional low temperature condensed liquid refrigerant. It has the same effect as the process of heating the hot gas refrigerant to a high-temperature, low-pressure gas refrigerant using a hot gas heat storage and reevaporation device, so there is no need for a large and expensive conventional hot gas heat storage and reevaporation device. Refrigerating machine oil that adheres or accumulates in the evaporator is sprayed into the hot liquid refrigerant spray chamber by the liquid refrigerant pump every time the defrost is performed and returned to the compressor, so there is no problem with refrigerating machine oil return, and during cooling. The heat exchange efficiency of the evaporator is also improved. The configurations of the defrosting method and defrosting device according to the first to fourth inventions of the above claims are all defrosting methods and defrosting devices in the case of one compressor and one evaporator, By increasing the number of valves and changing the control device, a plurality of evaporators can be cooled and defrosted simultaneously, and the defrosting device of the second invention and the defrosting device of the fourth invention A defrosting method and a defrosting device using a liquid refrigerant pump that uses both hot liquid refrigerant and hot gas in a dry evaporator can be obtained. The defrosting method and defrosting device of the first to fourth inventions do not require a large-sized device, are economical, have low defrosting power consumption, and defrost in a short time,
Therefore, the rise in temperature inside the warehouse was small, and the effect of suppressing quality deterioration of stored products was achieved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a defrosting method and defrosting device using a refrigerant liquid pump for a dry evaporator according to the second and second claims, and Fig. 2 is a block diagram of a defrosting device according to the third and fourth claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a defrosting method and a defrosting device using a refrigerant liquid pump of a dry evaporator of the invention. 1 In Figure 2, dotted arrows indicate liquid refrigerant, - dot arrows indicate hot liquid refrigerant, two-dot arrows indicate defrosting liquid refrigerant, three-dot arrows indicate hot gas, and straight arrows indicate suction gas refrigerant. Indicates the direction of movement within the pipe. In the figure, l...suction valve, 2. liquid valve, 3. liquid receiver liquid supply valve, 4.. defrosted liquid valve, 5.. liquid refrigerant pump, 6. liquid refrigerant circulation for defrosting. Valve, 7. Defrost control device, 8. Compressor, 9. Liquid receiver, 10. Liquid refrigerant heating coil, 11. Heat storage tank, 16.. Heat storage temperature controller, 17.. Hot gas bypass valve, 18..
Defrosting end temperature regulator, 19... Receiver liquid return valve, 20
・Defrosting liquid refrigerant extraction pipe, 21・Expansion valve, 22・Check valve, 23・Suction pipe, 24・Liquid pipe, 25・Liquid receiver liquid supply pipe, 26・・Three branch part, 27 Evaporator Outlet pipe, 28 Receiver liquid return pipe, 29 Supply liquid amount control valve, 30... Suction/discharge pipe, 31/ Gas-liquid separator, 32 Hot liquid refrigerant spray chamber, 33
・Discharge pipe, 34...Hot gas pipe, 35 Hot gas valve,
36 Hot gas inflow pipe, 37 Spray liquid amount control valve.

Claims (1)

[Claims] 1. The dry evaporator is provided with a hot liquid refrigerant inlet pipe and a defrosted liquid refrigerant outlet pipe, and a liquid refrigerant pump is used to supply the hot liquid refrigerant between the liquid refrigerant heating coil and the dry evaporator. A liquid dry evaporator characterized by comprising a defrosting liquid refrigerant circulation pipe, performing defrosting by circulating hot liquid refrigerant, and providing an automatic opening/closing valve in the suction pipe, which is closed during defrosting. Defrosting method using a refrigerant pump. 2. A hot liquid refrigerant inflow pipe and a defrosted liquid refrigerant take-out pipe are installed in the dry evaporator, and a liquid refrigerant pump is used to supply the defrosting liquid refrigerant between the liquid refrigerant heating coil and the dry evaporator. A method of defrosting using a liquid refrigerant pump of a dry evaporator, which is characterized by configuring a circulation pipe, circulating hot liquid refrigerant to perform defrosting, and providing an automatic opening/closing valve in the suction pipe, which is closed during defrosting. frost device. 3. The dry evaporator is equipped with a hot gas inflow pipe and a defrosted liquid refrigerant take-out pipe, and a liquid refrigerant pump is used to suck the hot gas condensate refrigerant from the defrosted liquid refrigerant take-out pipe. A liquid refrigerant pump for a dry evaporator is used, which is characterized by passing the refrigerant through a heating coil to form a hot liquid refrigerant and spraying it into the suction pipe, and installing an automatic opening/closing valve in the suction pipe, which is closed during defrosting. Defrosting method. 4. The dry evaporator is equipped with a hot gas inflow pipe and a defrosted liquid refrigerant take-out pipe, and a liquid refrigerant pump is used to suck the hot gas condensate refrigerant from the defrosted liquid refrigerant take-out pipe. A liquid refrigerant pump for a dry evaporator is used, which is characterized by passing the refrigerant through a heating coil to form a hot liquid refrigerant and spraying it into the suction pipe.The suction pipe is equipped with an automatic opening/closing valve, which is closed during defrosting. Defrost equipment.