Oil return device of high-temperature water-cooling screw unit

Abstract

The technical scheme of the utility model discloses an oil return device of a high-temperature water-cooling screw unit. The oil return device comprises an oil separator, a first filter, an oil cooler, a first electromagnetic valve, a second filter, an oil return electromagnetic valve and a compressor, an inlet of the oil separator is connected with an exhaust port of the compressor, a low-pressure oil groove of the compressor is connected with an inlet of the oil cooler through a compressor oil cooling inlet pipe, and a bottom oil outlet of the oil separator is connected with the compressor oil cooling inlet pipe. A second filter and an oil return electromagnetic valve are sequentially installed between a bottom oil outlet of the oil separator and a compressor oil cooling inlet pipe, a high oil level switch and a low oil level switch are arranged on a bottom oil pocket of the oil separator, the high oil level switch and the low oil level switch are arranged on the bottom oil pocket of the oil separator, opening of the oil return electromagnetic valve is controlled, and the oil return process is controlled. And the second filter is matched, so that the oil return quantity is stable, the oil return efficiency is high, and the unit working effect is good.

Description

Technical Field

[0001] The utility model belongs to the technical field of compressors, and in particular relates to an oil return device for a high-temperature water-cooled screw unit. Background Art

[0002] Water-cooled screw units generally use full liquid or falling film evaporators. Due to the limitations of the compressor structure, its built-in oil separator cannot meet the overall unit operation requirements. It is necessary to add an external oil separator and adopt a water-cooled screw secondary oil separation and oil return solution. The bottom of the oil separator is connected to the compressor suction port bypass. The oil separated by the secondary oil separator returns to the compressor suction port through the pressure difference. Due to the different operating loads of the unit, the bypass flow is different, and the problem of too much or too little bypass volume is prone to occur; when the bypass volume is large, the refrigerant bypass volume is large, affecting the unit's working performance. When the bypass volume is small, the return oil is small and the unit cannot operate normally. At the same time, the return oil directly enters the suction port, part of the oil returns to the oil tank, and the other part is discharged with the refrigerant, resulting in low oil return efficiency.

[0003] Patent CN 103629866 B discloses an oil return control system and method for a refrigeration compressor and an air conditioning unit having the same, including an oil separator, a secondary oil return interface, the secondary oil return interface is connected to the low-pressure suction end of the refrigeration compressor, a secondary oil return pipeline, connected between the secondary oil return interface of the oil separator and the low-pressure suction end of the refrigeration compressor, an oil level switch, arranged on the oil separator, a solenoid valve arranged on the secondary oil return pipeline, a control device electrically connected to the oil level switch and the solenoid valve respectively, when the position switch measures that the oil level in the oil separator is lower than the set value, the oil level switch is disconnected, the solenoid valve is powered off and closed, at this time, the lubricating oil and the high-pressure gas cannot return to the suction end of the compressor through this circuit, if the oil level is higher than the set value, the oil level switch is in a closed state, the solenoid valve is powered on and opened, the lubricating oil can return to the suction end of the compressor through this circuit, but the stability of the return oil amount cannot be controlled. Therefore, it is necessary to design an oil return device that can stabilize the return oil amount while the oil of the oil separator returns to the compressor to ensure efficient operation of the compressor. Utility Model Content

[0004] In order to solve the existing technical problems, the utility model provides an oil return device for a high-temperature water-cooled screw unit. A high oil level switch and a low oil level switch are arranged in the oil bag at the bottom of the oil separator to control the opening of the oil return solenoid valve and the oil return process. In combination with a second filter, the oil return amount is stabilized, the oil return efficiency is high, and the unit working effect is good.

[0005] The technical scheme of the utility model is: an oil return device for a high-temperature water-cooled screw unit, comprising an oil separator, a first filter, an oil cooler, a first solenoid valve, a second filter, an oil return solenoid valve and a compressor; the inlet of the oil separator is connected to the exhaust port of the compressor, the low-pressure oil tank of the compressor is connected to the inlet of the oil cooler through an oil cooling inlet pipe of the compressor, there are two oil cooler outlets, one outlet of the oil cooler is connected to the air intake port of the compressor, the other outlet of the oil cooler is connected to the inlet of the first filter, and the first filter outlet is connected to the inlet of the low-pressure oil tank of the compressor; the bottom oil outlet of the oil separator is connected to the oil cooling inlet pipe of the compressor, the second filter and the oil return solenoid valve are sequentially installed between the bottom oil outlet of the oil separator and the oil cooling inlet pipe of the compressor, and a high oil level switch and a low oil level switch are arranged in the bottom oil bag of the oil separator; the oil cooling inlet pipe of the compressor is directly connected to the inlet of the first filter through a bypass pipe, and the first solenoid valve is installed on the bypass pipe.

[0006] Furthermore, a test mirror is installed between the first filter and the inlet of the low-pressure oil tank of the compressor.

[0007] Furthermore, an angle valve is installed between the compressor oil cooling inlet pipe and the oil cooler inlet.

[0008] Furthermore, the bottom oil bag capacity of the oil separator is ≥5L.

[0009] The working principle of the oil return device of a high-temperature water-cooled screw unit of the utility model is as follows: a mixture of oil and refrigerant sprayed from the exhaust port of the compressor enters the oil separator, and after separation by the oil separator, the oil enters the bottom oil bag of the oil separator, and the unit controls the switch of the oil return solenoid valve according to the high oil level switch and the low oil level switch. When the unit is started, the oil return solenoid valve is in a closed state. When the high oil level switch detects that the oil level is at a high oil level, the oil return solenoid valve is opened, and the oil in the bottom oil bag of the oil separator passes through the second filter, the oil return solenoid valve, and the compressor oil cooling inlet pipe in turn into the oil cooler. The oil cooled by the oil cooler passes through the first filter and enters the low-pressure oil tank of the compressor; when the low oil level switch detects that the oil level is at a low oil level, the oil return solenoid valve is closed, and the oil is stored and accumulated in the bottom oil bag of the oil separator until the oil volume reaches the high oil level, and the oil return solenoid valve is opened again to return the oil.

[0010] When the oil in the low-pressure oil tank of the compressor needs to be cooled, the first solenoid valve is closed, and the oil enters the compressor oil cooling inlet pipe from the low-pressure oil tank of the compressor, and then enters the oil cooler for cooling. When the oil in the compressor oil cooling inlet pipe does not need to be cooled, the first solenoid valve is opened, and the oil directly enters the first filter from the compressor oil cooling inlet pipe. When there are many impurities in the oil cooler and it needs to be filtered, the oil enters the first filter for filtration and then flows back to the low-pressure oil tank of the compressor. When there are fewer impurities in the oil in the oil cooler, the oil flows directly from the oil cooler to the suction port of the compressor.

[0011] By adopting the above technical solution, the beneficial effects achieved by the utility model are as follows:

[0012] (1) The utility model sets a high oil level switch and a low oil level switch at the bottom oil bag of the oil separator, connects the oil separator to the oil cooling inlet and finally to the low-pressure oil tank of the compressor, controls the opening of the oil return solenoid valve by the high oil level switch and the bottom oil level switch, controls the oil return process, realizes the oil in the oil separator returns to the compressor, and cooperates with the second filter to realize the stability of the oil return amount, prevents the refrigerant from being mixed in the oil during the oil return, and affects the performance of the unit, and has high oil return efficiency and good unit working effect.

[0013] (2) By increasing the bottom oil bag capacity of the oil separator and coordinating with the high oil level switch and the low oil level switch, good oil return efficiency can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the utility model.

[0015] In the figure, oil separator 1, first filter 2, oil cooler 3, first solenoid valve 4, second filter 5, oil return solenoid valve 6, compressor 7, compressor oil cooling inlet pipe 8, high oil level switch 9, low oil level switch 10, test mirror 11, angle valve 12. DETAILED DESCRIPTION

[0016] The utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0017] Example 1

[0018] Reference Figure 1 In the invention, a high-temperature water-cooled screw unit oil return device comprises an oil separator 1, a first filter 2, an oil cooler 3, a first solenoid valve 4, a second filter 5, an oil return solenoid valve 6 and a compressor 7; the inlet of the oil separator 1 is connected to the exhaust port of the compressor 7, the low-pressure oil tank of the compressor 7 is connected to the inlet of the oil cooler 3 through the compressor oil cooling inlet pipe 8, the oil cooler 3 has two outlets, one outlet of the oil cooler 3 is connected to the air intake port of the compressor 7, the other outlet of the oil cooler 3 is connected to the inlet of the first filter 2, and the outlet of the first filter 2 is connected to the inlet of the low-pressure oil tank of the compressor 7; the bottom oil outlet of the oil separator 1 is connected to the compressor oil cooling inlet pipe 8, the second filter 5 and the oil return solenoid valve 6 are sequentially installed between the bottom oil outlet of the oil separator 1 and the compressor oil cooling inlet pipe 8, and the bottom oil bag of the oil separator 1 is provided with a high oil level switch 9 and a low oil level switch 10; the compressor oil cooling inlet pipe 8 is directly connected to the inlet of the first filter 2 through a bypass pipe, and the first solenoid valve 4 is installed on the bypass pipe.

[0019] When the high oil level switch 9 detects that the oil level in the bottom oil bag of the oil separator 1 is at a high oil level, the oil return solenoid valve 6 is opened, and the oil in the bottom oil bag of the oil separator 1 is filtered by the second filter 5 and enters the oil cooler 3 for cooling. The oil in the oil bag is filtered by the second filter 5 to reduce impurities in the return oil. Combined with the filtering effect of the first filter 2, the pipeline blockage is reduced, the pipeline flow is maintained stable, and the stability of the return oil volume is greatly improved, and the return oil efficiency is high. When the low oil level switch 10 detects that the oil level is at a low oil level, the oil return solenoid valve 6 is closed, and the oil is stored and accumulated in the bottom oil bag of the oil separator 1 to prevent the refrigerant from being mixed in the oil during the oil return and affecting the performance of the unit. When the amount of oil in the bottom oil bag of the oil separator 1 reaches a high oil level, the oil return is restarted to ensure that the return oil volume is stable and there will be no excessive or insufficient return oil.

[0020] Furthermore, a test mirror 11 is installed between the first filter 2 and the inlet of the low-pressure oil tank of the compressor 7 to facilitate observation of the oil return condition in the pipeline.

[0021] Furthermore, an angle valve 12 is installed between the compressor oil cooling inlet pipe 8 and the inlet of the oil cooler 3 , and cooperates with the first solenoid valve 4 to control the amount of oil entering the oil cooler 3 .

[0022] Furthermore, the bottom oil bag capacity of the oil separator 1 is 5L. Increasing the bottom oil bag capacity of the oil separator 1, in conjunction with the high oil level switch 9 and the low oil level switch 10, is conducive to achieving a stable return oil volume.

[0023] The working principle of the oil return device of a high-temperature water-cooled screw unit of the utility model is as follows: a mixture of oil and refrigerant sprayed from the exhaust port of the compressor 7 enters the oil separator 1, and after separation by the oil separator 1, the oil enters the bottom oil bag of the oil separator 1, and the unit controls the switch of the oil return solenoid valve 6 according to the high oil level switch 9 and the low oil level switch 10. When the unit is turned on, the oil return solenoid valve 6 is in a closed state. When the high oil level switch 9 detects that the oil level is at a high oil level, the oil return solenoid valve 6 is opened, and the oil in the bottom oil bag of the oil separator 1 passes through the second filter 5, the oil return solenoid valve 6, and the compressor oil cooling inlet pipe 8 in sequence to enter the oil cooler 3. The oil cooled by the oil cooler 3 passes through the first filter 2 and enters the low-pressure oil tank of the compressor 7; when the low oil level switch 10 detects that the oil level is at a low oil level, the oil return solenoid valve 6 is closed, and the oil is stored and accumulated in the bottom oil bag of the oil separator 1 until the oil volume reaches a high oil level, and the oil return solenoid valve 6 is opened again to return the oil.

[0024] When the oil in the low-pressure oil tank of the compressor 7 needs to be cooled, the first solenoid valve 4 is closed, and the oil enters the compressor oil cooling inlet pipe 8 from the low-pressure oil tank of the compressor 7, and then enters the oil cooler 3 for cooling. When the oil in the compressor oil cooling inlet pipe 8 does not need to be cooled, the first solenoid valve 4 is opened, and the oil directly enters the first filter 2 from the compressor oil cooling inlet pipe 8. When the oil in the oil cooler 3 has a lot of impurities and needs to be filtered, the oil enters the first filter 2 for filtration and then flows back to the low-pressure oil tank of the compressor 7. When the oil in the oil cooler 3 has a few impurities, the oil flows directly from the oil cooler 3 into the air intake of the compressor 7.

Claims

1. A high-temperature water-cooled screw unit oil return device, characterized in that: The invention comprises an oil separator (1), a first filter (2), an oil cooler (3), a first solenoid valve (4), a second filter (5), an oil return solenoid valve (6) and a compressor (7); the inlet of the oil separator (1) is connected to the exhaust port of the compressor (7); the low-pressure oil tank of the compressor (7) is connected to the inlet of the oil cooler (3) through a compressor oil cooling inlet pipe (8); the oil cooler (3) has two outlets in total, one outlet of the oil cooler (3) is connected to the air intake port of the compressor (7), and the other outlet of the oil cooler (3) is connected to the inlet of the first filter (2). The oil separator (1) is connected to the oil inlet of the compressor (7); the outlet of the first filter (2) is connected to the inlet of the low-pressure oil tank of the compressor (7); the bottom oil outlet of the oil separator (1) is connected to the compressor oil cooling inlet pipe (8); a second filter (5) and an oil return solenoid valve (6) are installed in sequence between the bottom oil outlet of the oil separator (1) and the compressor oil cooling inlet pipe (8); a high oil level switch (9) and a low oil level switch (10) are provided at the bottom oil bag of the oil separator (1); the compressor oil cooling inlet pipe (8) is directly connected to the inlet of the first filter (2) through a bypass pipe, and a first solenoid valve (4) is installed on the bypass pipe.

2. The high-temperature water-cooled screw unit oil return device according to claim 1, characterized in that: A test mirror (11) is installed between the first filter (2) and the inlet of the low-pressure oil tank of the compressor (7).

3. The high-temperature water-cooled screw unit oil return device according to claim 1, characterized in that: An angle valve (12) is installed between the compressor oil cooling inlet pipe (8) and the inlet of the oil cooler (3).

4. The high-temperature water-cooled screw unit oil return device according to claim 1, characterized in that: The oil bag capacity at the bottom of the oil separator (1) is ≥5L.

Images