JPH028668A - Defrosting device for freezer - Google Patents

Abstract

PURPOSE:To perform a defrosting operation without reducing a cooling efficiency by a method wherein a defrosting gas supplying pipe is connected to a cooling coil through a header, a branch pipe arranged at an outlet port of a distributor is inserted into the cooling coil and an extremity end opening of the branch pipe is directed toward an outlet port of the cooling coil. CONSTITUTION:During a defrosting cycle, a defrosting solenoid valve is opened, a compressor is operated to supply a discharging gas from a header 2 to each of cooling coils 1. The gas is liquified at each of the cooling coils and frost is removed with a condensation heat. The liquified coolant enters a liquid-gas separator tank, flows down a heat receiving coil, evaporated by heat from a thermal accumulation tank, thereafter the gas is sucked by a compressor 8 and circulated. In this way, during a freezing cycle, coolant flowed out of the extremity ends of branch pipes 6a, 6b and 6c is promoted to be gasified under an action of fins 7, so that the coolant is not flowed back to the header 2 in a narrow space between the outer circumferences of the branch pipes 6a, 6b and 6c and an inner circumferences of the cooling coils 1. Accordingly, the coolant is flowed toward the outlet ports of the cooling coils 1 inserted into the extremity ends of the branch pipes and the coolant may not flow into other cooling coils.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a defrosting mechanism in which, when frost adheres to a cooling coil, a refrigerant gas from a defrosting river is flowed into the cooling coil and the condensation heat is used to remove the frost. This invention relates to refrigerators equipped with a cooling system, and particularly relates to improvements in refrigerators equipped with a plurality of cooling coils.

(Prior Art) When a plurality of cooling coils are used, a distributor is connected to the inlet side of the cooling coil to distribute refrigerant from an expansion valve to each cooling coil.

Conventionally, when supplying defrosting refrigerant gas to multiple cooling coils each having a distributor, the tip of the defrosting gas supply pipe is directly connected to the distributor, and the defrosting gas is connected to the flow of refrigerant in the refrigeration cycle. Similarly, each cooling coil was supplied via a distributor.

(Problem to be solved by the invention) However, unlike the refrigerant flowing in the refrigeration cycle, the defrosting gas is a complete gas, so it has a large flow resistance. Conventionally, the disadvantage was that defrosting gas could not be supplied and the defrosting efficiency was poor.

Expanding the pipe line of the distributor will reduce resistance and allow a sufficient amount of defrosting gas to flow, but on the other hand, the entire distributor will become larger and the pipes will be difficult to weld, increasing costs.

On the other hand, if the defrost gas could be supplied by connecting a thick pipe dedicated to the defrost gas to each cooling coil via a header, without going through a distributor.

The distributor is convenient because it can supply a sufficient amount of defrosting gas to the cooling coil as before without increasing the size.

However, in this case, since the refrigerant gas for cooling flows into the header in the refrigeration cycle, there is a risk that the cold tofu gas will concentrate on the cooling coil, which has lower passage resistance.
If the refrigerant concentrates in one cooling coil, not only will the other cooling coils not work effectively, but the liquid will return from the cooling coil, and the temperature sensing cylinder of the expansion valve installed on the outlet side will sense this. This will automatically throttle the expansion valve.
Cooling efficiency will drop significantly.

Therefore, in the present invention, in consideration of these circumstances, in order to avoid increasing the size of the distributor, the defrosting gas supply pipe is connected to the cooling coil via the header, but during the refrigeration cycle, the refrigerant flows into the header. The objective is to prevent refrigerant from concentrating on some cooling coils, thereby defrosting without reducing cooling efficiency.

(Means for Solving the Problems) In the present invention, a defrosting gas supply pipe is connected to each inlet side end of a plurality of cooling coils via a header. Then, a distributor is connected to the outlet side pipe of the expansion valve, and a plurality of branch pipes provided on the outlet side of the distributor are inserted into the cooling coil pipe from the respective inlet side ends of the cooling coil described in 1i71. The tip opening is configured to face the exit 11 side of the cooling coil.

(Operation) During defrosting according to the present invention, the defrosting gas flows from the supply pipe through the header and around the outer periphery of the insertion portion of the branch pipe, and is distributed to each cooling coil.

During the refrigeration cycle, snow-like refrigerant is ejected from the expansion valve and is supplied from the distributor to each cooling coil through the opening at the end of the branch pipe.The refrigerant gasifies within the cooling coil and expands in volume, causing flow resistance. increase.

In addition to the fact that the actual pipe diameter on the inlet side of the cooling coil is narrowed due to the insertion of the branch pipe, the liquid discharged from the branch pipe passes through this narrow pipe diameter and temporarily flows to the header side. Even if it flows backwards, it gasifies on the way and increases resistance, so the refrigerant liquid does not flow backwards through the cooling coil to the header side, but instead flows toward the outlet side of the cooling coil.

Therefore, even if there is a difference in flow resistance between each cooling coil, the refrigerant once supplied to the cooling coil will not flow out to other cooling coils, and there is no risk that the refrigerant will concentrate in some cooling coils. do not have.

(Embodiment) Fig. 1.2 shows the main part of the embodiment of the present invention, and Fig. 3 shows the entire piping diagram.

Connect the header 2 to the inlet side ends of the three cooling coils l,
A defrosting gas supply pipe 3 is connected to one end of the header 2. Reference numeral 4 denotes an expansion valve, and three branch pipes 6a, 6b, and 6C branched from a conventionally known distributor 5 are connected to the outlet pipe of the expansion valve through the ladder 2 and from the inlet end of each cooling coil 1. It is inserted into the tube, and the tips of the branches 'ff6a, 6b, 6c are opened toward the outlet side of the cooling coil 1.

Numeral 7 denotes a large number of fins arranged at equal intervals around the outer circumference of the cooling coil l, and the tips of the branches v6a, 6b, and 6C are inserted deeply to a position of 2-in-7, 4 to 5 sheets inside of the outermost fin.

As for the length of the inserted portion of the branch pipe, it is desirable that its tip reaches at least inside the outermost fin.

8 is a compressor, and a condenser 9 is connected to the high pressure side piping on the discharge side 8a.
The outlet of the cooling coil 1 of the low-pressure side piping is connected to the suction side 8b of the compressor 8 via the pressure regulating valve 10 and the liquid-gas separation tank 11.

A heat receiving coil 12 is connected to the bottom of the liquid gas separation tank 11, and is buried in a heat storage tank 13 loaded with a heat insulating material (not shown) together with a heating coil (4) that is part of the high-pressure side piping. Then, the starting end of the defrosting gas supply pipe 3 is connected to the high-pressure side pipe between the heating coil 14 and the condenser 9.

15 is a solenoid valve for defrosting, and 16 is a thermo solenoid valve for preventing supercooling.

During the refrigeration cycle, high-pressure refrigerant gas discharged from the compressor 8 heats the heat storage tank 13 with the heating coil 14 and then reaches the condenser 9 where it is liquefied.
, the pressure drops and becomes snowy, and the branch pipe 6 is discharged from the distributor 5.
It is supplied to each cooling coil 1 via a, 6b, and 6C.

The refrigerant evaporates in the cooling coil 1, cools the surrounding area, becomes a gas, and passes through the pressure regulating valve 10 to the liquid-gas separation tank 1.
1, and is further sucked into the pressure Li1 machine 8 and circulated there.

During the defrost cycle, the defrost solenoid valve 15 is opened at pressure F.
The aa8 is operated and the discharged gas is supplied from the header 2 to each cooling coil 1, where it is liquefied and the condensation heat is used to remove frost.

The liquefied refrigerant enters the liquid gas separation tank 11, further flows down to the heat receiving coil 12, is re-evaporated by the heat of the heat storage 4fJ13, and is then sucked into the compressor 8 and circulated.

Therefore, during the refrigeration cycle, the branch pipe 6a.

Since the refrigerant flowing out from the tips of 6b and 6C is gasified by the action of the fins 7, it does not flow back into the header 2 through the narrow space between the outer periphery of the branch pipe and the inner periphery of the cooling coil 1. Therefore, the refrigerant flows from the branch pipe tip opening toward the exit side of the inserted cooling coil 1, and does not flow out to other adjacent cooling coils.

FIG. 4 shows an embodiment in which the header 2 is located above the cooling coil l, in which case the branch pipe 6 passes through the tube wall of the L-shaped bend of the cooling coil l connecting the header 2 to the cooling coil l. Insert it inside.

(Effects of the Invention) In short, in the present invention, since the branch pipes on the outlet side of the distributor are inserted into each of the plurality of cooling coils, the inlet sides of the cooling coils are connected with a header for supplying defrosting gas. However, during the refrigeration cycle, the refrigerant liquid flowing out from the branch pipe does not flow back to the header side, and each cooling coil is in a mutually separated and independent state. Therefore, even if some cooling coils have smaller flow resistance than others, the refrigerant does not concentrate there, but flows on average to all of the plurality of cooling coils, resulting in the effect of maintaining good cooling efficiency.

[Brief explanation of the drawing]

Fig. 1 is a side view of the main parts of an embodiment of the present invention, Fig. 2 is a plan view thereof (however, Fig. 1.2 partially omits the fins), and Fig. 3 is an overall piping diagram. It is. Figure m4 is a side view of the main parts of another embodiment. l is the cooling coil, 2 is the header, 3 is the defrosting gas supply pipe,
4 is an expansion valve, 5 is a distributor, 6a, 6b, 6C are branch pipes,
7 is a fin, 8 is a compressor, 9 is a condenser, 11 is a liquid-gas separation tank, and 15 is a defrosting solenoid valve. Figure 1 Patent applicant Agent: Nishinihon Seiki Seisakusho Co., Ltd.
Maki Tobe (and 3 others)

Claims (1)

[Claims] A defrosting gas supply pipe is connected to each inlet side end of the plurality of cooling coils via a header, and a distributor is connected to the outlet side piping of the expansion valve, and multiple branches are provided on the outlet side of the distributor. A defrosting device for a refrigerator comprising a tube inserted into the cooling coil tube from each inlet side end of the cooling coil, and tips of these branch tubes opening toward the outlet side of the cooling coil.