JPH05322427A - Refrigerating device - Google Patents

Abstract

PURPOSE:To prevent a liquid refrigerant from staying in a drain pan heater at the time of refrigerating operation. CONSTITUTION:A branch pipe 26 to a drain pan heater 27 is connected to an evaporator entrance pipe 25 which connect the exit side of an expansion valve 24 and the entrance side of an evaporator 21. A rising part 26a which rises upward from the connected part to the upper side of the evaporator entrance pipe 25 is formed on the branch pipe 26. By doing this, a liquid refrigerant of the refrigerant which becomes a 2-phape stream by being chilled when passing through the expansion valve 24 at the time of a refrigerating operation, can be prevented from flowing in the drain pan heater 27 and staying there.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus which circulates a refrigerant to perform freezing and defrosting, and more particularly to a refrigerating apparatus having a drain pan heater which is heated during defrosting operation.

[0002]

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

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

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

During the defrosting operation by the reverse cycle system, the refrigerant from the compressor is supplied to the outlet side of the evaporator 1 in the state of hot gas, and in the condensed state 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 of the refrigerant heats the drain pan 2 to melt the frozen drain and quickly discharge it.

[0006]

In the prior art shown in FIG. 4, the branch pipe 6 to the drain pan heater 7 is connected to the evaporator inlet pipe 5 connecting the outlet side of the expansion valve 4 and the inlet side of the evaporator 1. is doing. The drain pan heater 7 is disposed on the bottom surface of the drain pan 2 and is generally located lower than the evaporator inlet pipe 5. Therefore, the branch pipe 6 is connected to the lower side of the evaporator inlet pipe 5. In the prior art disclosed in Japanese Patent Laid-Open No. 62-5053, the connection state 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 to the lower side of the evaporator inlet pipe 5 as described above, as shown in FIG. 5, a gas refrigerant shown by a solid line and a liquid shown by a broken line are provided in the evaporator inlet pipe 5. Of the two-phase flow formed, part of the liquid refrigerant flows into the drain pan heater 7 and stays there. When the liquid refrigerant cooled by passing through the expansion valve 4 stays, frost 9 adheres to the drain pan 2a below the drain pan heater 7.

The evaporator 1 and the like shown in FIG. 4 are installed as an internal unit by being suspended from the ceiling of a freezer or the like. If the frost 9 adheres to the bottom surface 2a of the drain pan 2, the frost 9 may melt during the defrosting operation and drop as water droplets, which may wet the products in the warehouse.

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

[0010]

According to the present invention, in 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 an inlet side of an evaporator 21, a drain pan heater 27 is connected. The branch pipe 26 connects the expansion valve 24 and the evaporator 21 with an evaporator inlet pipe 25.
The refrigerating device is characterized in that it is connected to the upper side of.

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 of the evaporator inlet pipe 25 to the upper side.

[0012]

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. 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 the freezing 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 therein.

Further, according to the present invention, the branch pipe 26 is formed with a rising portion 26a extending upward from a connection point of the evaporator inlet pipe 25 to the upper side. 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, so that the liquid refrigerant flows into the drain pan heater and stays more reliably. Can be prevented.

[0014]

1 shows a schematic refrigerant piping system of a refrigerating apparatus according to an embodiment of the present invention. The refrigerating apparatus according to the present embodiment is divided into an indoor unit 10 that is hung and installed on the ceiling of a freezer or the like, and an outdoor unit 11 that is installed and used outside the freezer. Between the indoor unit 10 and the outdoor unit 11, the local pipeline 1
2 and 13 are connected. Shut-off valves 14 and 15 are provided in the middle of the on-site pipelines 12 and 13, respectively. The shutoff valves 14 and 15 are closed before the completion of the piping work and opened after the completion of the piping work.

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

Inside the internal unit 10, an evaporator 21, a fan 22, a high pressure liquid pipe 23, an expansion valve 24, and an evaporator inlet pipe 2 are provided.
5, branch pipe 26, drain pan heater 27, check valve 28,
A temperature sensitive tube 29, a dryer 30, and a flow diverter 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
Adiabatic expansion is performed in the expansion valve 24 and a part thereof becomes a gas refrigerant, which flows from the inlet side of the evaporator 21 via the evaporator inlet pipe 25 and the flow distributor 31. The evaporator 21 is also provided with fins 32 for efficiently exchanging heat with the internal air circulated by the fan 22. The evaporator 21 is provided with a plurality of pipe lines that thermally couple the plurality of fins 32, and the flow divider 31 divides the refrigerant. Evaporator 2
A temperature sensitive tube 29 is provided on the outlet side of 1. Temperature sensitive tube 29
Detects the temperature on the outlet side of the evaporator 21 and adjusts the opening degree of the expansion valve 24. A branch pipe 26 is connected to the upper side of the evaporator inlet pipe 25. A rising portion 26a extends further upward from the connection point of the branch pipe 26. The other side of the branch pipe 26 is connected to the drain pan heater 27. Drain pan heater 2
The other of 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 the outdoor unit 11 via a local pipe line 12. During the freezing operation, the evaporated gas 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 line including a solenoid valve 35 and a capillary tube 36 in order to perform liquid injection from the outlet side of the condenser 18.

When the four-way switching valve 17 is switched to the broken line position, the 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 the state of hot gas, and condenses while melting the frost adhering 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 through the rising portion 26a. The refrigerant flowing 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 on-site piping 13. From the on-site pipe line 13 flows into the condenser 18 via the filter 37 and the capillary tube 38, heat-exchanges with the outside air, and evaporates. 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 line is provided via the solenoid valve 39. The pressure switch 40 is used to detect when the discharge pressure from the compressor 16 exceeds the set value during the defrosting operation and to know when the defrosting operation ends.

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 the upper side of an evaporator inlet pipe 25 that connects the outlet side of the expansion valve 24 and the inlet side of the evaporator 21. Further, the rising portion 26a is formed so as to extend from this connection point. A drain pan 41 is provided below the evaporator 21 to discharge the drain generated during the defrosting operation. A branch pipe 26 is connected to the upper side of the evaporator inlet pipe 25, and the rising portion 26
Since a is provided, the liquid refrigerant does not flow into the branch pipe 26 side as shown in FIG. As a result, the cooled liquid refrigerant does not stay in the drain pan heater 27 during the freezing operation, and frost does not adhere to the bottom surface 41a of the drain pan 41. Note that in FIG. 2 as in 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 embodiment, the reverse cycle defrosting operation is performed to allow hot gas to flow in from the outlet side of the evaporator 21, the condensed liquid refrigerant is taken out from the inlet side of the evaporator 21, and the drain pan heater 27 is used. However, the hot gas bypass type defrosting operation is performed to discharge the hot gas discharged from the compressor to the drain pan heater 27.
Of course, it may be supplied to the inlet side of the evaporator via the.

[0022]

As described above, according to the present invention, since the branch pipe 26 to the drain pan heater 27 is connected to the upper side of the evaporator inlet pipe 25, 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 that flows in during the freezing operation, frost adheres to the bottom surface of the drain pan heater 27, and is melted during the defrosting operation to drop as water droplets to wet the products in the warehouse. Can be prevented.

Further, according to the present invention, since the branch pipe 26 is formed with the rising portion 26a extending further upward from the connection point to the upper side of the evaporator inlet pipe 25, the inflow of the liquid refrigerant during the refrigerating operation is further enhanced. It can be surely 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 drawings]

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

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

3 is an evaporator inlet pipe 25 and a 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 the joint between the evaporator inlet pipe 5 and the branch pipe 6 shown in FIG.

[Explanation of symbols] 10 indoor 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 rising part 27 drain pan heater 28 non-return Valve 29 Temperature-sensing cylinder 40 Pressure switch 41 Drain pan 41a Bottom surface

Claims (2)

[Claims] 1. A branch pipe 2 to a drain pan heater 27 that heats a drain pan during a defrosting operation on the inlet side of the evaporator 21.
In the refrigeration system to which 6 is connected, the branch pipe 26 to the drain pan heater 27 is
Is connected to the upper side of an evaporator inlet pipe 25 that connects between the evaporator 21 and the evaporator 21. 2. The branch pipe 26 has a rising portion 26a extending upward from a connection point of the evaporator inlet pipe 25 to the upper side.
The refrigerating apparatus according to claim 1, wherein the refrigerating apparatus is formed.