A plate heat exchanger oil return device

Abstract

This utility model discloses an oil return device for a plate heat exchanger. An oil collector interface is installed at the bottom of the refrigerant channel of the plate heat exchanger, opposite the refrigerant inlet, and an oil collector is connected to it. The oil collector is equipped with a heating device, and an oil return interface is located at the bottom of the oil collector, connected to the compressor suction end. The diameter of the oil collector interface is larger than the diameter of the oil return interface. This device is unaffected by the miscibility of the compressor lubricating oil and refrigerant. The bottom of the oil collector is not higher than the lowest point of the largest interface at the bottom of the plate heat exchanger, ensuring smooth return of compressor lubricating oil and preventing the compressor from malfunctioning due to insufficient oil. The heating device ensures that the temperature of the oil collector is higher than that of the plate heat exchanger, promoting the vaporization of liquid refrigerant in the oil collector. This minimizes the refrigerant content in the lubricating oil within the oil collector, ensuring the lubricating oil returns to the compressor while minimizing the entrainment of liquid refrigerant, effectively solving the all-condition oil return problem of plate heat exchangers.

Description

Technical Field

[0001] This utility model relates to an oil return device, and more particularly to an oil return device for a plate heat exchanger. Background Technology

[0002] In refrigeration and heat pump systems, the compressed refrigerant enters a heat exchanger for heat exchange before returning to the compressor for further compression. The compressor lubricating oil plays a crucial role during the compression process, circulating within the compressor to provide lubrication, sealing, cooling, and cleaning functions, ensuring stable operation and a long lifespan. Existing plate heat exchangers rely on refrigerant carrying oil back to the compressor, lacking a separate oil return device. In some operating conditions, the compressor lubricating oil and refrigerant have poor miscibility. Using a plate heat exchanger as an evaporator can lead to compressor lubricating oil accumulating in the heat exchanger, preventing timely return to the compressor and causing oil shortages or even malfunction. Utility Model Content

[0003] Purpose of the utility model: The purpose of this utility model is to solve the problem that the compressor cannot operate normally when using a plate heat exchanger as an evaporator under certain operating conditions due to the poor miscibility between the compressor lubricating oil and the refrigerant and the low oil return volume. This utility model provides an oil return device for plate heat exchangers.

[0004] Technical solution: The plate heat exchanger oil return device of this utility model has an oil collector interface set at the bottom of the refrigerant channel of the plate heat exchanger and opposite to the refrigerant inlet, and an oil collector is connected to it; the oil collector is equipped with a heating device and an oil return interface is set at the bottom of the oil collector, and the oil return interface is connected to the suction end of the compressor through an oil return pipeline; the diameter of the oil collector interface is larger than the diameter of the oil return interface.

[0005] Furthermore, the diameter of the oil collector interface of the plate heat exchanger should be larger than the diameter of the oil return interface and the diameter of the oil return pipe, so that the mixed liquid accumulates and is heated in the oil collector, and the refrigerant in the mixed liquid is heated and vaporized.

[0006] Furthermore, the heating temperature of the heating device is at least 5°C higher than the operating temperature of the plate heat exchanger. The heating device can be installed inside or outside the oil collector. Depending on the actual situation, industrial electric heating tubes, heat exchange coils, industrial electric heating cables, or a high-temperature heat source drawn from the unit can be selected for heating. With the heating device installed on the oil collector, the refrigerant in the mixed liquid is vaporized and returns to the plate heat exchanger to enter the refrigerant circulation loop. The liquid deposited in the oil collector is mostly lubricating oil, which returns to the compressor through the oil return pipeline, avoiding the situation where the compressor cannot operate normally due to lack of oil.

[0007] Furthermore, the bottom of the oil collector is not higher than the lowest point of the largest bottom inlet of the plate heat exchanger. The volume of the oil collector is 1 / 10 to 1 / 3 of the internal cavity volume of the plate heat exchanger. The oil collector inlet is located at the lowest end of the largest bottom inlet of the plate heat exchanger, and the height of the oil return inlet is lower than the lowest point of the largest bottom inlet of the plate heat exchanger. This prevents the compressor lubricating oil from accumulating again in the oil collector during the return flow process and failing to be discharged in time.

[0008] Beneficial effects: Compared with the prior art, the present invention has the following advantages: 1. It is not affected by the compatibility between compressor lubricating oil and refrigerant, and the compressor lubricating oil can flow back smoothly, avoiding the compressor from failing to operate normally due to lack of oil. 2. The heating device can further separate the refrigerant and compressor lubricating oil, preventing a large amount of liquid refrigerant and oil from returning to the compressor and affecting the compressor's operation. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of the first embodiment of the present utility model;

[0010] Figure 2 This is a schematic diagram of the structure of the second embodiment of the present utility model;

[0011] Figure 3 This is a structural schematic diagram of the third embodiment of the present utility model. Detailed Implementation

[0012] The technical solution of this utility model will be further described below with reference to the accompanying drawings.

[0013] Example 1

[0014] like Figure 1 The illustrated oil return device for a plate heat exchanger includes an oil collector interface 5 located at the bottom of the refrigerant channel of the plate heat exchanger 1, opposite the refrigerant inlet. The size of the oil collector interface 5 is the maximum opening diameter at the bottom of the plate heat exchanger. An oil collector 2 is connected to the oil collector interface 5, and the bottom of the oil collector 2 is not higher than the lowest point of the maximum opening diameter at the bottom of the plate heat exchanger. A heating device 4, which is an industrial electric heating element, is installed inside the oil collector 2. The oil collector 2 can be configured as follows: Figure 1The shape shown includes a spoon-shaped bottom and a top cover matching the bottom. The bottom of the spoon-shaped structure includes a straight pipe section serving as the handle and an arc-shaped surface with the spoon head opening upwards (it can also be other shapes to facilitate the smooth discharge of the mixed liquid, while also having a certain volume for the mixed liquid to collect). An oil return port 3 is located at the lowest point of the arc-shaped surface of the oil collector 2. The height of the oil return port 3 is lower than the lowest point of the largest port at the bottom of the plate heat exchanger 1. The oil return port 3 is connected to the compressor suction end via a oil return pipe. The diameter of the oil collector port 5 is larger than the diameter of the oil return port 3. The volume of the oil collector 2 is 1 / 10 to 1 / 3 of the internal cavity volume of the plate heat exchanger, and the volume of the oil collector 2 can be set according to the amount of oil accumulated under actual operating conditions.

[0015] Example 2

[0016] like Figure 2 As shown, unlike in Embodiment 1, the heating device 4 can be a heat exchange coil or an industrial electric heating tape.

[0017] Example 3

[0018] like Figure 3 As shown, unlike in Embodiment 1, the heating device 4 is located outside the oil collector 2, and the heating device can be an industrial electric heating tape.

[0019] The heating device 4 of this utility model is not limited to the three heating methods mentioned above. As long as the heating temperature is controlled to be at least 5°C higher than the operating temperature of the plate heat exchanger 1, a high-temperature heat source can also be drawn from the unit for heating.

[0020] During operation, when the throttled refrigerant enters the plate heat exchanger 1 for evaporation, the compressor lubricating oil entrained in the refrigerant will deposit inside the plate heat exchanger 1 and flow into the oil collector 2 along with some of the refrigerant through the bottom oil collector interface 5. After the heating device 4 heats the mixed liquid in the oil collector 2, most of the liquid refrigerant in the oil collector 2 vaporizes and returns to the plate heat exchanger 1, then returns to the compressor through the refrigerant circulation loop. The proportion of lubricating oil in the oil collector 2 increases, and the bottom oil return interface 3 of the oil collector 2 is connected to the compressor suction end through the oil return pipe. The compressor lubricating oil enriched in the oil collector 2 returns to the compressor through the oil return pipe to maintain stable compressor operation and prevent the compressor from failing to operate normally due to lack of oil. The heating device can further separate the refrigerant and compressor lubricating oil, preventing a large amount of liquid refrigerant and oil from returning to the compressor and affecting its operation, thereby ensuring the normal operation of the compressor.

Claims

1. A plate heat exchanger oil return device, characterized in that An oil collector interface (5) is set at the bottom of the refrigerant channel of the plate heat exchanger (1) and opposite to the refrigerant inlet, and an oil collector (2) is connected to it; the oil collector (2) is equipped with a heating device (4) and an oil return interface (3) is set at the bottom of the oil collector (2), and the oil return interface (3) is connected to the suction end of the compressor through an oil return pipeline; the diameter of the oil collector interface (5) is larger than the diameter of the oil return interface (3).

2. The plate heat exchanger oil return device according to claim 1, characterized in that The heating temperature of the heating device (4) is more than 5°C higher than the working temperature of the plate heat exchanger (1).

3. The plate heat exchanger oil return device according to claim 2, characterized in that The heating device (4) is located inside or outside the oil collector (2).

4. The plate heat exchanger oil return device of claim 1, wherein, The oil collector interface (5) is located at the lowest end of the largest interface at the bottom of the plate heat exchanger (1), and the bottom of the oil collector (2) is not higher than the lowest point of the largest interface at the bottom of the plate heat exchanger (1).

5. The plate heat exchanger oil return device according to claim 4, characterized in that The oil return port (3) is located at the lowest end of the oil collector (2).

6. The plate heat exchanger oil return device according to claim 5, characterized in that The height of the oil return port (3) is lower than the lowest point of the bottom maximum port of the plate heat exchanger (1).

7. The plate heat exchanger oil return device of claim 1, wherein The volume of the oil collector (2) is 1 / 10 to 1 / 3 of the internal cavity volume of the plate heat exchanger (1).

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