Low-pressure screw compressor

Abstract

The utility model relates to the technical field of air compression, in particular to a low-pressure screw compressor. In order to solve the problems that the exhaust temperature of an existing low-pressure screw compressor is too high, a compression main machine lacks oil, and abnormal sound is generated due to bearing abrasion, the utility model provides a low-pressure screw compressor, and a gas outlet of the compression main machine is communicated with a gas inlet of an oil gas barrel; a check valve and an oil pump are arranged between an oil discharge port of the oil gas barrel and a cooling oil inlet of the cooler, the check valve and the oil pump are arranged in parallel, and an exhaust port of the oil gas barrel is communicated with a cooling air inlet of the cooler; when the use pressure P is larger than or equal to 3 bar, the oil pump does not work, and lubricating oil in the oil gas barrel is conveyed into the cooler through the check valve to be cooled; when the pressure Plt is used; when the voltage is 3bar, the oil pump is started, and the lubricating oil in the oil gas barrel is conveyed into the cooler through the oil pump for cooling. The low-pressure screw compressor disclosed by the utility model can solve the problems of overhigh exhaust temperature, oil shortage of a compression main engine and abnormal sound caused by bearing abrasion.

Description

Technical Field

[0001] This utility model relates to the field of air compression technology, and in particular to a low-pressure screw compressor. Background Technology

[0002] In this field, low-pressure screw compressors typically refer to screw compressors operating within a pressure range of 0.2MPa-0.5MPa, with the main compressor's oil injection pressure required to be greater than 3MPa. When the discharge pressure of a low-pressure screw compressor is below 3MPa, the excessively long lubrication path can easily lead to a large pressure drop in the lubrication oil, resulting in insufficient oil injection from the main compressor. This affects the lubrication, cooling, and noise reduction effects of the main compressor, ultimately causing problems such as excessively high discharge temperature, insufficient oil supply to the main compressor, and abnormal noise caused by bearing wear. Utility Model Content

[0003] To address the problems of excessively high exhaust temperature, insufficient oil supply to the compressor, and abnormal noise caused by bearing wear in existing low-pressure screw compressors due to excessive pressure drop in lubricating oil, this invention proposes a low-pressure screw compressor. The compressor includes a compressor unit, an oil-gas separator, and a cooler. The exhaust port of the compressor unit is connected to the inlet of the oil-gas separator. A check valve and an oil pump are installed between the oil outlet of the oil-gas separator and the cooling oil inlet of the cooler, with the check valve and oil pump connected in parallel. The exhaust port of the oil-gas separator is connected to the cooling inlet of the cooler. When the operating pressure P of the low-pressure screw compressor is ≥ 3 bar, the oil pump does not operate, and the lubricating oil in the oil-gas separator is transported to the cooler for cooling via the check valve. When the operating pressure P of the low-pressure screw compressor is < 3 bar, the oil pump starts, and the lubricating oil in the oil-gas separator is transported to the cooler for cooling via the oil pump. Thus, when the operating pressure P of the low-pressure screw compressor of this invention is less than 3 bar, the oil pump starts to boost the pressure, allowing the lubricating oil in the oil-gas separator to be discharged and transported to the cooler for cooling. The oil pump and the check valve are connected in parallel to prevent the lubricating oil output by the oil pump from flowing back into the oil-gas separator, causing the oil pump to work repeatedly and thus wasting energy. When the operating pressure P of the low-pressure screw compressor of this invention is greater than or equal to 3 bar, the oil pump does not work, that is, the oil circuit branch where the oil pump is located is blocked, and the lubricating oil in the oil-gas separator is transported to the cooler for cooling via the check valve. Therefore, it can be seen that during the operation of the low-pressure screw compressor of this invention, the oil pump can boost the pressure when the operating pressure is low, avoiding problems such as excessively high exhaust temperature, insufficient oil in the compressor, and abnormal noise caused by bearing wear due to excessively low oil pressure.

[0004] Preferably, the oil inlet of the compressor and the cooling oil outlet of the cooler are connected by an oil inlet pipe, and an oil inlet pressure sensor electrically connected to the electronic control system is installed on the oil inlet pipe. When the compressed air pressure output by the low-pressure screw compressor of this invention drops instantaneously, the operating pressure of the low-pressure screw compressor of this invention will also drop rapidly, and the oil inlet pressure detected in real time by the oil inlet pressure sensor on the oil inlet pipe will also decrease. Therefore, when the oil inlet pressure sensor detects insufficient oil pressure injected into the compressor, the electronic control system can promptly start the oil pump to increase the pressure after receiving the oil inlet pressure signal from the oil inlet pressure sensor, thereby avoiding wear of bearings, rotors, and gearboxes due to lack of oil inside the compressor, resulting in high temperature and abnormal noise, and ensuring the stability of the oil circuit system in the low-pressure screw compressor of this invention. Furthermore, an oil filter is installed on the oil inlet pipe, and the oil filter is located between the oil inlet pressure sensor and the cooler. In this way, the lubricating oil output after cooling by the cooler is filtered by the oil filter before being injected into the compressor. This avoids the lubricating oil injected into the compressor from carrying impurities, which could affect the operation of the compressor or even damage it, thus affecting the service life of the low-pressure screw compressor of this invention.

[0005] Preferably, an exhaust temperature sensor is installed at the exhaust port of the oil-gas separator. This allows the exhaust temperature sensor to monitor the exhaust temperature of the oil-gas separator in real time during operation of the low-pressure screw compressor of this invention. This enables the electronic control system to monitor gas changes in the oil separator core in real time, issuing an early warning and controlling the compressor to shut down when the gas temperature in the oil separator core becomes abnormal. This prevents damage to the oil separator core due to sparks caused by excessively high temperatures in the oil-gas separator core, and even avoids burning out the low-pressure screw compressor of this invention. Furthermore, a pressure maintaining valve is installed between the exhaust temperature sensor and the oil-gas separator. This pressure maintaining valve at the exhaust port of the oil-gas separator helps maintain stable internal pressure in the gas path of the low-pressure screw compressor of this invention. More preferably, an exhaust pressure sensor is installed between the pressure maintaining valve and the exhaust temperature sensor. When the compressed air pressure output by the low-pressure screw compressor of this invention surges instantaneously, the compressed air flows backward. Because the pressure maintaining valve has a check valve function, the exhaust pressure at the exhaust port of the oil-gas separator in the low-pressure screw compressor of this invention increases, which is the exhaust pressure increase detected in real time by the exhaust pressure sensor. Therefore, when the exhaust pressure sensor detects an increase in the internal pressure of the air passage, the electronic control system, upon receiving the exhaust pressure signal from the exhaust pressure sensor, can control the operating speed of the compressor to reduce air intake.

[0006] Preferably, the compressor host is equipped with an intake valve and an air filter at its air inlet, with the intake valve located between the compressor host and the air filter. This allows the air entering the compressor host of the low-pressure screw compressor of this invention to be filtered by the air filter, removing impurities and preventing them from entering the compressor host and causing damage. Furthermore, the return air hole at the top of the oil-gas tank is connected to the air inlet of the intake valve via a return air pipe. This allows the compressed air in the oil-gas tank to flow back to the compressor host through the return air pipe when the pressure in the oil-gas tank is too high, reducing the pressure in the oil-gas tank and preventing compressed air from being directly discharged into the atmosphere and wasting energy.

[0007] Preferably, the oil return port of the compressor is connected to the oil separator in the oil-gas separator via a return oil pipe. Thus, during the operation of the low-pressure screw compressor of this invention, when the oil separator in the oil-gas separator separates the oil-gas mixture input from the compressor into the oil-gas separator, the lubricating oil accumulated in the oil separator can flow back to the compressor through the return oil pipe, preventing excessive accumulation of lubricating oil in the oil separator, which would affect the separation effect of the oil separator and even the quality of the compressed air output by the low-pressure screw compressor of this invention.

[0008] Preferably, a gas delivery temperature sensor is installed at the outlet of the compressor. This allows the gas delivery temperature sensor to monitor the temperature of the oil-gas mixture output by the compressor in real time during operation of the low-pressure screw compressor, facilitating the electronic control system to adjust the temperature and injection rate of the lubricating oil injected into the compressor based on the temperature of the oil-gas mixture. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the low-pressure screw compressor of this utility model. Detailed Implementation

[0010] Below, in conjunction with Figure 1 This invention provides a detailed description of the low-pressure screw compressor.

[0011] like Figure 1As shown, the low-pressure screw compressor of this invention includes a compressor main unit 1, an oil-gas tank 2, and a cooler 3. The outlet of the compressor main unit 1 is connected to the inlet of the oil-gas tank 2. A check valve 41 and an oil pump 42 are provided between the oil outlet of the oil-gas tank 2 and the cooling oil inlet of the cooler 3, and the check valve 41 and the oil pump 42 are arranged in parallel. The exhaust port of the oil-gas tank 2 is connected to the cooling inlet of the cooler 3. When the operating pressure P of the low-pressure screw compressor of this invention is ≥ 3 bar, the oil pump 42 does not work, and the lubricating oil in the oil-gas tank 2 is transported to the cooler 3 for cooling through the check valve 41. When the operating pressure P of the low-pressure screw compressor of this invention is < 3 bar, the oil pump 42 starts, and the lubricating oil in the oil-gas tank 2 is transported to the cooler 3 for cooling through the oil pump 42. Thus, when the operating pressure P of the low-pressure screw compressor of this invention is less than 3 bar, the oil pump 42 starts to boost the pressure, so that the lubricating oil in the oil-gas separator 2 is discharged and transported to the cooler 3 for cooling. The oil pump 42 and the check valve 41 are connected in parallel to prevent the lubricating oil output by the oil pump 42 from flowing back into the oil-gas separator 2, causing the oil pump 42 to do work repeatedly and thus wasting energy. When the operating pressure P of the low-pressure screw compressor of this invention is greater than or equal to 3 bar, the oil pump 42 does not work, that is, the oil circuit branch where the oil pump 42 is located is blocked, and the lubricating oil in the oil-gas separator 2 is transported to the cooler 3 for cooling via the check valve 41. It can be seen that during the operation of the low-pressure screw compressor of this invention, the oil pump 42 can boost the pressure when the operating pressure is low, avoiding the problems of excessively high exhaust temperature, insufficient oil in the compressor 1, and abnormal noise caused by bearing wear due to excessively low oil pressure. Preferably, the oil inlet of the compressor 1 and the cooling oil outlet of the cooler 3 are connected by an oil inlet pipe (not shown in the figure), and an oil inlet pressure sensor 11 electrically connected to the electronic control system (not shown in the figure) is installed on the oil inlet pipe. When the compressed air pressure output by the low-pressure screw compressor of this invention drops instantaneously, the operating pressure of the low-pressure screw compressor of this invention will also drop rapidly, and the oil inlet pressure detected in real time by the oil inlet pressure sensor 11 on the oil inlet pipe will also decrease. Therefore, when the oil inlet pressure sensor 11 detects insufficient oil pressure injected into the compressor 1, the electronic control system can start the oil pump 42 in time to increase the pressure after receiving the oil inlet pressure signal sent by the oil inlet pressure sensor 11, thereby avoiding the bearings, rotor and gearbox from wearing due to lack of oil, generating high temperature and abnormal noise due to lack of oil, and ensuring the stability of the oil circuit system in the low-pressure screw compressor of this invention. Preferably, an oil filter 12 is installed on the oil inlet pipe, and the oil filter 12 is located between the oil inlet pressure sensor 11 and the cooler 3. In this way, the lubricating oil output by the cooler 3 after cooling is filtered by the oil filter 12 and then injected into the compressor host 1. This can prevent the lubricating oil injected into the compressor host 1 from carrying impurities, which would affect the operation of the compressor host 1 or even damage the compressor host 1 and affect the service life of the low-pressure screw compressor of this utility model.

[0012] like Figure 1 As shown, an intake valve 13 and an air filter 14 are provided at the air inlet of the compressor unit 1, with the intake valve 13 located between the compressor unit 1 and the air filter 14. This allows the intake valve 13 to control the flow rate of air entering the compressor unit 1, and the air filter 14 to filter the air entering the compressor unit 1, removing impurities and preventing them from entering and damaging the compressor unit 1. Preferably, the return air hole at the top of the oil-gas tank 2 is connected to the air inlet of the intake valve 13 via a return air pipe (not shown in the figure). This allows the compressed air in the oil-gas tank 2 to flow back to the compressor unit 1 when the air pressure in the oil-gas tank 2 is too high, reducing the air pressure in the oil-gas tank 2 and preventing the compressed air from being directly discharged into the atmosphere and wasting it. Preferably, the oil return port of the compressor unit 1 is connected to the oil separator core 21 in the oil-gas tank 2 via an oil return pipe (not shown in the figure). Thus, during the operation of the low-pressure screw compressor of this invention, when the oil separator 21 in the oil-gas separator 2 separates the oil-gas mixture input from the compressor 1 into the oil-gas separator 2, the lubricating oil accumulated in the oil separator 21 can flow back to the compressor 1 through the return oil pipe, avoiding excessive accumulation of lubricating oil in the oil separator 21, which would affect the separation effect of the oil separator 21 and even the quality of the compressed air output by the low-pressure screw compressor of this invention. Preferably, a gas delivery temperature sensor 15 is provided at the outlet of the compressor 1. Thus, during the operation of the low-pressure screw compressor of this invention, the temperature of the oil-gas mixture output by the compressor 1 can be detected in real time by the gas delivery temperature sensor 15, so that the electronic control system can adjust the oil temperature and injection speed of the lubricating oil injected into the compressor 1 according to the temperature of the oil-gas mixture. Preferably, the compressor 1 is connected to the drive motor 6 through a coupling 5. Thus, the compressor 1 operates under the drive of the drive motor 6 to compress the intake air.

[0013] like Figure 1As shown, an exhaust temperature sensor 16 is installed at the exhaust port of the oil-gas tank 2. Thus, during the operation of the low-pressure screw compressor of this invention, the exhaust temperature sensor 16 can be used to monitor the exhaust temperature of the oil-gas tank 2 in real time. This allows the electronic control system to monitor the gas changes in the oil separator core 21 within the oil-gas tank 2 in real time, issuing an early warning and controlling the compressor to shut down when the gas temperature in the oil separator core 21 is abnormal. This prevents damage to the oil separator core 21 due to excessively high temperature, which could even burn out the low-pressure screw compressor of this invention. Preferably, a pressure maintaining valve 17 is installed between the exhaust temperature sensor 16 and the oil-gas tank 2. This pressure maintaining valve 17 at the exhaust port of the oil-gas tank 2 helps maintain the stability of the internal pressure of the gas path in the low-pressure screw compressor of this invention. Preferably, an exhaust pressure sensor 18 is installed between the pressure maintaining valve 17 and the exhaust temperature sensor 16. When the compressed air pressure output by the low-pressure screw compressor of this invention surges instantaneously, the compressed air flows backward. Because the pressure maintaining valve 17 has a check valve function, the exhaust pressure at the exhaust port of the oil-gas separator 2 in the low-pressure screw compressor of this invention increases, i.e., the exhaust pressure sensor 18 detects an increase in exhaust pressure in real time. Therefore, when the exhaust pressure sensor 18 detects an increase in the internal pressure of the air passage, the electronic control system, upon receiving the exhaust pressure signal from the exhaust pressure sensor 18, can control the operating speed of the compressor and gradually close the intake valve 13 to reduce air intake.

[0014] When the low-pressure screw compressor of this invention is running, air is first filtered by air filter 14 and then enters the compressor host 1 through intake valve 13. After being compressed by the compressor host 1, an oil-gas mixture is formed and input into oil-gas tank 2. The oil separator core 21 in oil-gas tank 2 separates the oil-gas mixture to obtain compressed air and oil mist. The compressed air accumulates at the top of oil-gas tank 2 and is discharged through the exhaust port of oil-gas tank 2 and sent to cooler 3 for cooling before being supplied to the user. When too much compressed air accumulates in oil-gas tank 2, that is, when the air pressure in oil-gas tank 2 is too high, the compressed air in oil-gas tank 2 can flow back to the compressor host 1 through the return air pipe for re-compression. Part of the oil mist accumulates at the bottom of the oil-gas tank 2 and is transported to the cooler 3 through the oil drain pipe for cooling treatment to obtain cooled lubricating oil. This cooled lubricating oil can be injected into the compressor 1 through the oil inlet pipe to lubricate and cool the compressor 1. The other part of the oil mist accumulates in the oil separator 21 and flows back to the compressor 1 through the oil return pipe. Therefore, in the low-pressure screw compressor of this invention, the lubricating oil of the compressor 1 can be recycled, which can reduce the operating cost of the low-pressure screw compressor of this invention.

Claims

1. A low-pressure screw compressor, characterized in that The low-pressure screw compressor includes a compressor main unit, an oil-gas separator, and a cooler. The outlet of the compressor main unit is connected to the inlet of the oil-gas separator. A check valve and an oil pump are installed between the oil outlet of the oil-gas separator and the cooling oil inlet of the cooler, and the check valve and the oil pump are connected in parallel. The exhaust port of the oil-gas separator is connected to the cooling inlet of the cooler. When the operating pressure P of the low-pressure screw compressor is ≥ 3 bar, the oil pump does not work, and the lubricating oil in the oil-gas separator is transported to the cooler for cooling via the check valve. When the operating pressure P of the low-pressure screw compressor is less than 3 bar, the oil pump starts, and the lubricating oil in the oil-gas tank is transported to the cooler for cooling via the oil pump.

2. Low-pressure screw compressor according to claim 1, characterized in that The oil inlet of the compressor is connected to the cooling oil outlet of the cooler through an oil inlet pipe, and an oil inlet pressure sensor electrically connected to the electronic control system is installed on the oil inlet pipe.

3. Low-pressure screw compressor according to claim 2, characterized in that An oil filter is installed on the oil inlet pipe, and the oil filter is located between the oil inlet pressure sensor and the cooler.

4. Low-pressure screw compressor according to any of claims 1 to 3, characterized in that An exhaust temperature sensor is installed at the exhaust port of the oil and gas tank.

5. Low-pressure screw compressor according to claim 4, characterized in that A pressure maintaining valve is provided between the exhaust temperature sensor and the oil-gas tank.

6. Low-pressure screw compressor according to claim 5, characterized in that An exhaust pressure sensor is provided between the pressure maintaining valve and the temperature sensor.

7. Low-pressure screw compressor according to any of claims 1 to 3, characterized in that An intake valve and an air filter are provided at the air inlet of the compressor unit, and the intake valve is located between the compressor unit and the air filter.

8. Low-pressure screw compressor according to claim 7, characterized in that The return air hole at the top of the oil and gas tank is connected to the air inlet of the air inlet valve through a return air pipe.

9. Low-pressure screw compressor according to any of claims 1 to 3, characterized in that The return port of the compressor is connected to the oil separator core in the oil-gas tank via a return pipe.

10. The low-pressure screw compressor according to any one of claims 1 to 3, characterized in that, A gas delivery temperature sensor is installed at the outlet of the compressor unit.

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