JP2836374B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system for performing refrigeration and defrosting by circulating a refrigerant, and more particularly to a refrigeration system having a drain pan heater which is heated during a defrosting operation.

[0002]

2. Description of the Related Art Conventionally, in order to efficiently perform a defrosting operation, a drain pan heater is provided in an evaporator so that drain generated during defrosting is quickly discharged. For example,
In the prior art disclosed in Japanese Patent Application Laid-Open No. Sho 62-5053, during defrosting operation, hot gas discharged from a compressor is guided to a drain pan heater and introduced into the evaporator from the inlet side of the evaporator. The defrosting operation by the hot gas bypass system which performs defrosting is performed.

In the above-mentioned prior art, a pipe for guiding hot gas from a drain pan heater to an evaporator during a hot gas bypass type defrosting operation is connected halfway from the outlet side of the expansion valve to the inlet side of the evaporator. doing. Also in a refrigerating apparatus that performs a defrosting operation by a reverse cycle method, a branch pipe to a drain pan heater is connected between an outlet side of an expansion valve and an inlet side of an evaporator.

FIG. 4 shows a part of a refrigerant piping system related to a drain pan heater of a refrigeration system for performing a defrosting operation by a reverse cycle method. The evaporator 1 is mounted on a drain pan 2 that receives drain generated during a defrosting operation. During the refrigeration operation, the liquid refrigerant from the condenser is supplied to the expansion valve 4 via the high-pressure liquid pipe 3. The liquid refrigerant undergoes adiabatic expansion when passing through the expansion valve 4, and at least a part thereof becomes a gas, flows through the evaporator inlet pipe 5 as a two-phase flow of the liquid and the gas, and is supplied to the evaporator 1.

[0005] During the defrosting operation by the reverse cycle method, the refrigerant from the compressor is supplied to the outlet side of the evaporator 1 in a hot gas state, and condensed from the inlet side of the evaporator 1 to the branch pipe 6 side. be introduced. The refrigerant introduced into the branch pipe 6 flows into the high-pressure liquid pipe 3 via the drain pan heater 7 and the check valve 8. When the refrigerant passes through the drain pan heater 7, the heat heats the drain pan 2 to melt the frozen drain and quickly discharge it.

[0006]

In the prior art shown in FIG. 4, a branch pipe 6 to a drain pan heater 7 is connected to an evaporator inlet pipe 5 connecting the outlet side of the expansion valve 4 and the inlet side of the evaporator 1. doing. The drain pan heater 7 is disposed on the bottom surface of the drain pan 2 and is generally located at a position lower than the evaporator inlet pipe 5. For this reason, the branch pipe 6 is connected to the lower side of the evaporator inlet pipe 5. In the prior art disclosed in JP-A-62-5053, the connection between the inlet side of the evaporator and the drain pan heater is the same.

With the structure in which the branch pipe 6 is connected below the evaporator inlet pipe 5 as described above, as shown in FIG. 5, the evaporator inlet pipe 5 is formed from a gas refrigerant indicated by a solid line and a liquid indicated by a broken line. In the two-phase flow, a part of the liquid refrigerant flows into the drain pan heater 7 and stays there. When the liquid refrigerant cooled after passing through the expansion valve 4 stays, frost 9 adheres to the drain pan 2 a below the drain pan heater 7.

[0008] The evaporator 1 and the like shown in FIG. 4 are installed as hanging units on the ceiling or the like of a freezer. If the frost 9 adheres to the bottom surface 2a of the drain pan 2, it may melt and drop as water droplets during the defrosting operation, and may wet products in the refrigerator.

It is an object of the present invention to provide a refrigeration apparatus in which liquid refrigerant does not flow into a drain pan heater during a refrigeration operation.

[0010]

The present invention relates to a refrigerating apparatus in which a branch pipe 26 to a drain pan heater 27 for heating a drain pan during a defrosting operation is connected to the inlet side of the evaporator 21. The branch pipe 26 is an evaporator inlet pipe 25 connecting the expansion valve 24 and the evaporator 21.
Is connected to the upper side of the refrigerator.

Further, the present invention is characterized in that the branch pipe 26 is formed with a rising portion 26a extending upward from a connection point on the upper side of the evaporator inlet pipe 25.

[0012]

According to the present invention, the branch pipe to the drain pan heater 27 is connected above the evaporator inlet pipe 25. The evaporator inlet pipe 25 is connected between the expansion valve 24 and the evaporator 21, and a two-phase flow of a gas refrigerant and a liquid refrigerant flows during a refrigeration operation. Since the branch pipe 26 is connected to the upper side, it is possible to prevent the liquid refrigerant from flowing into the drain pan heater 27 and staying there.

Further, according to the present invention, the branch pipe 26 is formed with a rising portion 26a extending upward from a connection point on the upper side of the evaporator inlet pipe 25. This makes it difficult for the liquid refrigerant to flow into the drain pan heater 27 beyond the rising portion 26a even if the liquid refrigerant flows into the branch pipe 26. Therefore, it is possible to more reliably prevent the liquid refrigerant from flowing into the drain pan heater and staying there. Can be prevented.

[0014]

FIG. 1 shows a schematic refrigerant piping system of a refrigerating apparatus according to one embodiment of the present invention. The refrigeration apparatus according to the present embodiment is separated into an indoor unit 10 suspended and installed on a ceiling such as a freezer and an outdoor unit 11 installed and used outside the freezer. Between the indoor unit 10 and the outdoor unit 11,
2 and 13. On the way of the on-site piping lines 12 and 13, closing valves 14 and 15 are provided, respectively. The closing valves 14 and 15 are closed before the completion of the plumbing work, and are opened after the completion of the plumbing work.

The outdoor unit 11 includes a compressor 16, a four-way switching valve 17, and a condenser 18 which are main components of the refrigerant circuit.
And so on. A fan 19 is provided to cool the condenser 18. During the refrigeration operation, the high-pressure gas refrigerant discharged from the compressor 16 passes through the four-way switching valve 17 at the solid line position, is condensed by the condenser 18 and turns into a liquid refrigerant, passes through the check valve 20 in the forward direction, and is It is supplied to the in-compartment unit 10 via the path 13.

The evaporator 21, fan 22, high-pressure liquid pipe 23, expansion valve 24, evaporator inlet pipe 2
5, branch pipe 26, drain pan heater 27, check valve 28,
A temperature sensing tube 29, a dryer 30, and a flow divider 31 are included. The liquid refrigerant supplied from the outdoor unit 11 during the freezing operation flows into the expansion valve 24 via the high-pressure liquid pipe 23 and the dryer 30. The liquid refrigerant flowing into the expansion valve 24 is
A part of the refrigerant becomes a gas refrigerant by adiabatic expansion in the expansion valve 24 and flows in from the inlet side of the evaporator 21 via the evaporator inlet pipe 25 and the flow divider 31. The evaporator 21 is also provided with fins 32 for efficiently exchanging heat with air in the refrigerator circulated by the fan 22. The evaporator 21 is provided with a plurality of piping paths thermally connecting the plurality of fins 32, and the refrigerant is divided by the flow divider 31. Evaporator 2
A temperature-sensitive cylinder 29 is provided at the exit side of the unit 1. Temperature sensing tube 29
Detects the temperature of the outlet side of the evaporator 21 and adjusts the opening of the expansion valve 24. A branch pipe 26 is connected to the upper side of the evaporator inlet pipe 25. From the connection point of the branch pipe 26, the rising portion 26a extends further upward. The other end of the branch pipe 26 is connected to a drain pan heater 27. Drain pan heater 2
7 is connected to the high-pressure liquid pipe 23 via a check valve 28.

The outlet side of the indoor unit 10 is connected to an outdoor unit 11 via a local piping 12. During the freezing operation, the evaporated gaseous refrigerant returns from the outlet side of the evaporator 21 to the outdoor unit 11 side, and is guided to the accumulator 33 via the four-way switching valve 17. The refrigerant guided to the accumulator 33 is sucked into the compressor 16 via the compressor accumulator 34. The compressor 16 is provided with a liquid injection pipe including a solenoid valve 35 and a capillary tube 36 for performing liquid injection from the outlet side of the condenser 18.

When the four-way switching valve 17 is switched to the position indicated by the broken line, a reverse cycle defrosting operation is performed. The refrigerant discharged from the compressor 16 flows from the outlet side to the inlet side of the evaporator 21 in a hot gas state, and condenses while melting frost attached to the evaporator 21. The refrigerant flowing out from the inlet side of the evaporator 21 flows into the branch pipe 26 from the evaporator inlet pipe 25 via the rising portion 26a. The refrigerant that has flowed into the branch pipe 26 flows into the drain pan heater 27 to be heated, flows through the check valve 28 in the forward direction, and flows into the local piping 13. From the on-site piping 13, it flows into the condenser 18 via the filter 37 and the capillary tube 38, and exchanges heat with the outside air to evaporate. The gas refrigerant from the condenser 18 is sucked into the compressor 16 via the four-way switching valve 17, the accumulator 33, and the compressor accumulator 34.

Between the discharge side and the suction side of the compressor 16,
A bypass pipe is provided via an electromagnetic valve 39. The pressure switch 40 is used to detect when the discharge pressure from the compressor 16 exceeds a set value during the defrosting operation, and to know when the defrosting operation has ended.

FIGS. 2 and 3 show the branch pipe 26 shown in FIG.
2 shows a refrigerant piping system related to. A branch pipe 26 is connected to an upper side of an evaporator inlet pipe 25 connecting between an outlet side of the expansion valve 24 and an inlet side of the evaporator 21. Further, a rising portion 26a is formed to extend from this connection point. A drain pan 41 is provided below the evaporator 21 to discharge drain generated during the defrosting operation. A branch pipe 26 is connected to the upper side of the evaporator inlet pipe 25 and has a rising portion 26.
3, the liquid refrigerant does not flow into the branch pipe 26 as shown in FIG. As a result, the liquid refrigerant cooled in the drain pan heater 27 does not stay during the freezing operation, and frost does not adhere to the bottom surface 41a of the drain pan 41. In FIG. 2, similarly to FIG. 4, the solid line indicates the flow of the gas refrigerant, and the broken line indicates the flow of the liquid refrigerant.

In the above-described embodiment, the reverse cycle type defrosting operation is performed, hot gas flows in from the outlet side of the evaporator 21, and the condensed liquid refrigerant is taken out from the inlet side of the evaporator 21, and is discharged from the drain pan heater 27. However, a hot gas bypass type defrosting operation is performed, and the hot gas discharged from the compressor is supplied to the drain pan heater 27.
Of course, it is also possible to supply to the inlet side of the evaporator via.

[0022]

As described above, according to the present invention, the branch pipe 26 to the drain pan heater 27 is connected to the upper side of the evaporator inlet pipe 25, so that the liquid refrigerant flows into the drain pan heater 27 and stays there. Can be prevented. As a result, the drain pan heater 27 is cooled by the liquid refrigerant flowing during the freezing operation, frost adheres to the bottom surface of the drain pan heater 27, etc., melts during the defrosting operation, drops as water droplets, and wets products in the refrigerator. Can be prevented.

According to the present invention, the branch pipe 26 is formed with the rising portion 26a extending further upward from the connection point on the upper side of the evaporator inlet pipe 25, so that the inflow of the liquid refrigerant during the freezing operation is further improved. It can be reliably prevented.
That is, even if a part of the liquid refrigerant flows into the branch pipe 26,
This is because it is difficult to pass the rising portion 26a against gravity.

[Brief description of the drawings]

FIG. 1 is a schematic refrigerant piping system diagram of a refrigeration apparatus according to one embodiment of the present invention.

FIG. 2 is a more detailed refrigerant piping system diagram around a branch pipe 26 shown in FIG.

FIG. 3 shows the evaporator inlet pipe 25 and the branch pipe 26 shown in FIG.
FIG. 4 is a side view showing a part of the vicinity of the connection part of FIG.

FIG. 4 is a refrigerant piping system diagram of a conventional refrigeration system.

5 is a cross-sectional view of the vicinity of a joint between the evaporator inlet pipe 5 and the branch pipe 6 shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 In-compartment unit 11 Outdoor unit 16 Compressor 17 Four-way switching valve 18 Condenser 21 Evaporator 23 High-pressure liquid pipe 24 Expansion valve 25 Evaporator inlet pipe 26 Branch pipe 26a Rise part 27 Drain pan heater 28 Non-return valve 29 Temperature-sensitive cylinder 40 pressure switch 41 drain pan 41a bottom surface

Claims (2)

(57) [Claims] 1. A branch pipe (2) to an inlet side of an evaporator (21) to a drain pan heater (27) for heating a drain pan during a defrosting operation.
In the refrigerating device to which the drain valve 6 is connected, the branch pipe 26 to the drain pan heater 27
And a refrigeration apparatus, which is connected to an upper side of an evaporator inlet pipe 25 connecting the refrigeration apparatus and the evaporator 21. 2. The branch pipe 26 has a rising portion 26a extending upward from a connection point on the upper side of the evaporator inlet pipe 25.
The refrigeration apparatus according to claim 1, wherein: