Vacuum pipeline speed-adjustable oil pumping device and oil pumping method thereof

Abstract

The invention discloses an oil pumping device with a speed-adjustable vacuum pipeline, aiming at the problem of leakage of the existing oil pumping device of the vacuum pipeline, an oil pump body, an oil outlet electromagnetic valve and an oil inlet electromagnetic valve are connected through a three-way ferrule joint, the oil outlet electromagnetic valve is communicated with an oil filling pipeline, and the oil inlet electromagnetic valve is communicated with a vacuum oil tank; a stainless steel pipe on the upper portion of a stainless steel telescopic corrugated assembly in the oil pump body penetrates through an upper hole of an oil pump base, and the stainless steel pipe and an oil pump shield are fixed to the oil pump base through a sealing assembly to serve as an oil inlet. The upper end of the stainless steel pipe is connected with the vertical lower end of the three-way ferrule joint; the lower end face of the stainless steel telescopic corrugated assembly is flush with the upper end plane of the limiting ejector rod, and a rod body of the limiting ejector rod penetrates through a lower hole of the oil pump protective cover and is fixed to the oil pump protective cover through a sealing assembly. A sealing ring is placed in a sealing groove in the outer side of the oil pump base and is in threaded connection with the oil pump shield to form a closed cavity; reliable oil pumping is achieved in the mode that positive pressure and negative pressure are applied alternately.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil pumping, and particularly relates to an oil pumping device with adjustable speed for a vacuum pipeline and an oil pumping method thereof. Background Art

[0002] The main function of an oil pumping device is to transfer a liquid (such as fuel oil, lubricating oil, etc.) from one container to another container or system by mechanical or electric means. Such devices are widely used in multiple fields such as automobiles, construction machinery, ships, chemical industry, agriculture, etc., for operations such as lubrication, cooling, oil supply, and water pumping.

[0003] To improve the reliability of the oil pumping device for a vacuum pipeline, existing methods use devices such as peristaltic pumps and oil cylinders for oil pumping, but there are problems that components such as hoses and sealing rings are prone to wear and aging, resulting in leakage of the device and affecting the overall pipeline vacuum degree. Summary of the Invention

[0004] The purpose of the present invention is to provide an oil pumping device with adjustable speed for a vacuum pipeline to delay or avoid leakage of the oil pumping device.

[0005] To solve the above problems, the technical solution of the present invention is as follows: An oil pumping device with adjustable speed for a vacuum pipeline, comprising: an oil pump body, an outlet solenoid valve, an inlet solenoid valve, an air path switching three-way solenoid valve, and a pressure control electro-hydraulic proportional valve; The oil pump body, the outlet solenoid valve, and the inlet solenoid valve are connected through a three-way ferrule joint. The outlet solenoid valve is communicated with an oil filling pipeline, and the inlet solenoid valve is communicated with a vacuum oil tank; The oil pump body includes a stainless steel telescopic corrugated component, an oil pump base, and an oil pump shield. The stainless steel pipe at the upper part of the stainless steel telescopic corrugated component passes through the hole on the oil pump base and is fixed on the oil pump base through a sealing component with the oil pump shield, serving as the inlet; the upper end of the stainless steel pipe is connected to the vertically downward end of the three-way ferrule joint; the lower end surface of the stainless steel telescopic corrugated component is flush with the upper plane of the limit ejector rod. The rod body of the limit ejector rod passes through the lower hole of the oil pump shield and is fixed on the oil pump shield through a sealing component; a sealing ring is placed in the outer sealing groove of the oil pump base and is threadedly connected with the oil pump shield to form a sealed cavity; The first port of the air path switching three-way solenoid valve is connected to the oil pump shield through a quick connector, its second port is connected to the air outlet of the pressure control electro-hydraulic proportional valve, and its third port is connected to a vacuum negative pressure source; The air inlet of the pressure control electro-hydraulic proportional valve is connected to a positive pressure air source.

[0006] According to an embodiment of the present invention, the top of the oil pump base is provided with a threaded through hole, and an axial sealing groove is arranged at the bottom of the through hole for fixing the stainless steel telescopic corrugated component; The bottom of the oil pump base is provided with threads and a sealing groove for connecting with the oil pump shield to form a sealed cavity.

[0007] According to an embodiment of the present invention, the oil pump shield is in a cylindrical shape, and the stainless - steel telescopic corrugated component and the limit ejector rod are arranged inside the oil pump shield; the stainless - steel pipe of the stainless - steel telescopic corrugated component extends out of the top of the oil pump shield and is inserted into the through - hole of the oil pump base; The bottom of the oil pump shield is provided with a threaded lower hole, and the rod body of the limit ejector rod passes through the lower hole of the oil pump shield and is fixed by a sealing component; An installation through - hole is arranged at a position on the side of the oil pump shield close to the lower hole for installing a quick - connect fitting.

[0008] According to an embodiment of the present invention, the sealing component includes a U - shaped sealing ring, a through - hole gasket and a through - hole fastener arranged in sequence. The bottom of the through - hole fastener has threads, and the end of the through - hole fastener has an external hexagon.

[0009] According to an embodiment of the present invention, the stainless - steel telescopic corrugated component includes a semi - enclosed cavity and a stainless - steel pipe. One end of the stainless - steel pipe is connected to the opening of the semi - enclosed cavity, and the other end is inserted into the through - hole of the oil pump base, serving as the only channel for the vacuum oil to enter and exit; The semi - enclosed cavity includes a telescopic stainless - steel corrugated section. The bottom of the semi - enclosed cavity is a plane for contacting the limit ejector rod to limit the internal volume of the cavity.

[0010] According to an embodiment of the present invention, the stiffness range of the telescopic stainless - steel corrugated section is 0.5 - 200 N / mm, the compression ratio range is 50 - 70%, and the tensile ratio range is 15 - 20%.

[0011] According to an embodiment of the present invention, the limit ejector rod is in a T - shape. The rod body of the limit ejector rod extends out of the bottom of the oil pump shield and is fixed and sealed to limit the extension position of the stainless - steel telescopic corrugated component.

[0012] A method for pumping oil with adjustable speed in a vacuum pipeline, applied to an oil - pumping device with adjustable speed in a vacuum pipeline, includes: When pumping oil in, open the solenoid valve at the oil inlet, close the solenoid valve at the oil outlet, switch the gas - path switching three - way solenoid valve to the negative - pressure pipeline, so that a vacuum is formed inside the oil pump shield. The internal and external pressure difference of the stainless - steel telescopic corrugated component is converted into a natural extension state. The silicone oil in the vacuum oil tank flows from the vacuum oil tank into the internal cavity of the stainless - steel telescopic corrugated component through the pipeline under the influence of gravity to achieve oil absorption; When pumping oil, open the oil outlet solenoid valve, close the oil inlet solenoid valve, switch the gas path three-way solenoid valve to the positive pressure pipeline, and the pressure control electro-hydraulic proportional valve outputs according to the preset air pressure. Under the action of the pressure difference between the oil pump shield and the vacuum pipeline, the stainless steel telescopic corrugated component contracts, and the silicone oil inside it is extruded by the air pressure and enters the vacuum oil filling pipeline to realize oil pumping.

[0013] According to an embodiment of the present invention, by adjusting the output air pressure of the pressure control electro-hydraulic proportional valve, the pressure difference inside the oil pump shield is adjusted, so as to achieve the purpose of changing the oil outlet speed.

[0014] According to an embodiment of the present invention, by changing the end position of the limit ejector rod, the extension position of the stainless steel telescopic corrugated component is changed, so as to achieve the purpose of adjusting the single oil pumping volume.

[0015] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art: The vacuum pipeline adjustable speed oil pumping device in an embodiment of the present invention aims at the problem of leakage in the existing vacuum pipeline oil pumping device. It uses a stainless steel flexible telescopic corrugated component as the core of oil pumping, combines the solenoid valve switches at the inlet and outlet of the device, and realizes the purpose of reliable oil pumping through the alternating positive and negative pressure externally. Preferably, the pipeline is made of all stainless steel materials, and the oil pumping is realized in a vacuum sealed cavity, without contacting air and other media throughout the process, avoiding oil product pollution. Its core components have a longer service life and a higher vacuum degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of the vacuum pipeline adjustable speed oil pumping device in an embodiment of the present invention; Figure 2 is a schematic diagram of the oil pump body parts in an embodiment of the present invention.

[0017] Description of the reference numerals: 1: oil pump body; 11: oil pump base; 12: oil pump shield; 13: quick connector; 14: through-hole fastener; 15: through-hole gasket; 16: non-skeleton U-shaped sealing ring; 17: stainless steel telescopic corrugated component; 18: stainless steel pipe; 19: limit ejector rod; 2: oil outlet solenoid valve; 3: oil inlet solenoid valve; 4: gas path switching three-way solenoid valve; 5: pressure control electro-hydraulic proportional valve; 6: three-way ferrule joint. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The following further describes in detail a vacuum pipeline adjustable speed oil pumping device and its oil pumping method proposed by the present invention with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will be clearer according to the following description and the claims.

[0019] Please refer to Figure 1, this embodiment provides a pump oil device with adjustable speed for a vacuum pipeline, including: an oil pump body 1, an oil outlet solenoid valve 2, an oil inlet solenoid valve 3, a gas path switching three-way solenoid valve 4, and a pressure control electro-hydraulic proportional valve 5; among them, the oil pump body 1, the oil outlet solenoid valve 2, and the oil inlet solenoid valve 3 are connected through a three-way ferrule joint 6. The oil outlet solenoid valve 2 is connected to the vacuum oil filling pipeline, and the oil inlet solenoid valve 3 is connected to the vacuum oil tank. Specifically, the oil outlet solenoid valve 2 adopts a ferrule connection method. Through a stainless steel pipe, it is connected to the left side of the vacuum oil filling pipeline and the left connection port of the three-way ferrule joint 6 on the right side. The oil inlet solenoid valve 3 adopts a ferrule connection method. Through a stainless steel pipe, it is connected to the right side of the vacuum oil tank and the right connection port of the three-way ferrule joint 6 on the left side. The stainless steel pipe on the upper part of the stainless steel telescopic corrugated component of the oil pump body 1 passes through the hole on the oil pump base and is fixed to the oil pump base through a sealing component with the oil pump shield, serving as the oil inlet. The upper end of the stainless steel pipe is connected to the vertically downward end of the three-way ferrule joint 6.

[0020] In actual application, the oil pump body 1 adopts an aluminum cylinder shell, with a stainless steel oil pipe above and a stainless steel ejector rod (used to limit the single pump oil volume) below. There is a quick-connect air pipe joint near the ejector rod at the lower side. As the core of the pump oil, by alternately switching the inlet and outlet valves and coordinating with the air pressure inside the oil pump body, the purpose of pumping oil is achieved.

[0021] The oil outlet solenoid valve 2 is of the DC 24V normally closed type, with a stainless steel valve body, one inlet and one outlet. Both the inlet and outlet are equipped with ferrule hard seal interfaces, conducting when powered on and cutoff when powered off. The ultimate vacuum is better than 1×10 -13 Pa·m 3 / s, used to control the oil flowing from the oil pump into the vacuum oil filling pipeline and prevent the oil in the vacuum oil filling pipeline from flowing back to the oil pump.

[0022] The oil inlet solenoid valve 3 is of the DC 24V normally closed type, with a stainless steel valve body, one inlet and one outlet. Both the inlet and outlet are equipped with ferrule hard seal interfaces, conducting when powered on and cutoff when powered off. The ultimate vacuum is better than 1×10 -13 Pa·m 3 / s, used to control the oil flowing from the vacuum oil tank into the oil pump body and prevent the oil in the oil pump body from flowing back to the vacuum oil tank.

[0023] The three-way ferrule joint 6 adopts a stainless steel valve body, with an overall T-shaped structure. The two ends extend horizontally, and the third end extends vertically downward, forming a 90° angle. Both the horizontal ends and the vertical end adopt ferrule hard seal interfaces and can be connected to pipelines in different directions respectively. It is used to connect the inlet and outlet valves in the horizontal direction and the oil pump body in the vertically downward direction.

[0024] The oil pump body is the core device of this device. Please refer to Figure 2, the oil pump body 1 includes a stainless - steel telescopic corrugated component 17, an oil pump base 11, and an oil pump shield 12. The stainless - steel pipe 18 at the upper part of the stainless - steel telescopic corrugated component 17 passes through the hole on the oil pump base 11 and is fixed to the oil pump base 11 together with the oil pump shield 12 through a sealing component, serving as the oil inlet. The upper end of the stainless - steel pipe 18 is connected to the vertically downward end of the three - way ferrule joint 6; the lower end surface of the stainless - steel telescopic corrugated component 17 is flush with the upper - plane of the limiting ejector rod 19. The rod body of the limiting ejector rod 19 passes through the lower hole of the oil pump shield 12 and is fixed to the oil pump shield 12 through a sealing component. A sealing ring is placed in the outer sealing groove of the oil pump base 11 and is thread - connected to the oil pump shield 12 to form a sealed cavity, sealing the upper parts of the stainless - steel telescopic corrugated component 17 and the limiting ejector rod 19.

[0025] Specifically, the oil pump base 11 is made of aluminum alloy, with a cylindrical structure with a thin - walled concave top. It has a through - hole with threads at the top, and an axial sealing groove for installing a sealing ring at the bottom of the through - hole, which is used to fix the stainless - steel telescopic corrugated component 17; its bottom is provided with connecting threads and a sealing groove, which is used to form a sealed cavity in combination with the oil pump shield 12, and the formed cavity is used to install the stainless - steel telescopic corrugated component 17 and the limiting ejector rod 19.

[0026] The oil pump shield 12 is made of aluminum alloy, with a cylindrical structure with a thin - walled concave bottom. It has a lower hole with threads at the bottom, and an axial sealing groove for installing a sealing ring at the bottom of the lower hole; a threaded mounting through - hole is provided at a position near the lower part of its side, which is used to install a quick - connect fitting; its top is provided with connecting threads and a sealing groove, which is used to form a sealed cavity in combination with the oil pump base 11.

[0027] The through - hole fastener 14 is made of stainless steel, with threads at the bottom and an external hexagon at the top, having a through - hole structure, and forms a sealing component in combination with the through - hole gasket 15 and the non - skeleton U - shaped sealing ring 16.

[0028] The through - hole gasket 15 is made of stainless steel, with a stainless - steel cylindrical structure with a through - hole, and forms a seal in combination with the non - skeleton U - shaped sealing ring 16.

[0029] The non - skeleton U - shaped sealing ring 16, made of fluororubber, is the main sealing component, and forms a seal in combination with the through - hole gasket 15.

[0030] The stainless - steel telescopic corrugated component 17 is the core of pumping oil, including a semi - enclosed cylindrical cavity with a conduit (stainless - steel pipe 18). Leak detection is carried out at the conduit, and the leak rate is better than 1×10 -13 Pa·m 3 / s. The stainless steel pipe 18 is used to insert into the through hole of the oil pump base 11 and serves as the only channel for the vacuum oil to enter and exit the assembly. The bottom closed plane of the stainless steel telescopic corrugated assembly 17 is used to contact the limit ejector rod 19 to limit the maximum volume inside the assembly. The stainless steel corrugated part in the semi-closed cylindrical cavity has a stiffness of 0.5 - 200 N / mm, a compression rate of 50 - 70%, a tensile rate of 15 - 20%, and can be telescoped more than 1 million times.

[0031] The limit ejector rod 19 is a T-shaped stainless steel solid cylinder structure. The lower rod body is fixedly sealed with the oil pump shield 12 through a sealing assembly and serves as the extension limit position of the stainless steel telescopic corrugated assembly.

[0032] The first port of the gas path switching three-way solenoid valve 4 of the device is connected to the oil pump shield 12 through a quick connector 13. Its second port is connected to the air outlet of the pressure control electro-pneumatic proportional valve 5, and its third port is connected to the vacuum negative pressure source. The air inlet of the pressure control electro-pneumatic proportional valve 5 is connected to the positive pressure air source.

[0033] Among them, the quick connector 13 is an air pipe quick connector and is used to connect the air outlet of the gas path switching solenoid valve 4 to the oil pump shield 12. In practical applications, the right thread of the quick connector 13 is screwed into the lower left thread hole of the oil pump shield 12, and the left side of the quick connector 13 is connected to the right air outlet of the gas path switching three-way solenoid valve 4 through a hose.

[0034] The gas path switching solenoid valve 4 is a DC 24V normally closed type, with an aluminum valve body, a vacuum type two-way three-way, and is used to switch the oil pushing air pressure inside the oil pump body.

[0035] The pressure control electro-pneumatic proportional valve 5 is powered by DC 24V, (analog) voltage / current conversion air pressure output, with an aluminum valve body, one inlet and one outlet, and cooperates with the analog input value to control the positive pressure inside the oil pump body.

[0036] The above device uses a stainless steel flexible telescopic corrugated assembly as the core of pumping oil, combines the solenoid valve switches at the inlet and outlet of the device, and realizes the purpose of reliable oil pumping by the way of alternating positive and negative pressures applied externally. Preferably, the pipeline is made of all stainless steel material, and the oil pumping is realized in a vacuum-sealed cavity, without contacting air and other media throughout the process, avoiding oil product pollution. Its core components have a longer service life and a higher vacuum degree. Moreover, by changing the end position of the limit ejector rod and changing the extension position of the stainless steel telescopic corrugated assembly, the single oil pumping volume can be adjusted; by adjusting the output air pressure of the pressure control electro-pneumatic proportional valve, the pressure difference inside the oil pump shield can be adjusted, achieving the purpose of changing the oil outlet speed, and thus improving the oil pumping efficiency.

[0037] The following specifically introduces the oil pumping method of the device: When refueling, open the solenoid valve at the fuel inlet, close the solenoid valve at the fuel outlet, and switch the three-way solenoid valve for gas circuit to the negative pressure pipeline, so as to form a vacuum inside the oil pump guard. The internal and external pressure difference of the stainless steel telescopic corrugated component is converted into a natural extension state, and the silicone oil in the vacuum oil tank flows from the vacuum oil tank into the internal cavity of the stainless steel telescopic corrugated component through the pipeline under the influence of gravity, realizing oil absorption.

[0038] When discharging oil, open the solenoid valve at the oil outlet, close the solenoid valve at the fuel inlet, and switch the three-way solenoid valve for gas circuit to the positive pressure pipeline. The pressure control electro-hydraulic proportional valve outputs according to the preset air pressure. Under the action of the pressure difference between the oil pump guard and the vacuum pipeline, the stainless steel telescopic corrugated component shrinks, and the silicone oil inside it is extruded by the air pressure into the vacuum oil filling pipeline, realizing oil pumping.

[0039] When adjusting the pump speed, by adjusting the magnitude of the output air pressure of the pressure control electro-hydraulic proportional valve, the magnitude of the pressure difference inside the oil pump guard is adjusted, so as to achieve the purpose of changing the oil discharge speed.

[0040] When adjusting the limit, by changing the end position of the limit ejector rod, the extension position of the stainless steel telescopic corrugated component is changed, so as to achieve the purpose of adjusting the single pump oil volume.

[0041] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and its equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A pump oil device with adjustable speed for a vacuum pipeline, characterized in that, Comprising: An oil pump body, an outlet solenoid valve, an inlet solenoid valve, a pneumatic circuit switching three-way solenoid valve, and a pressure control electro-hydraulic proportional valve; The oil pump body, the outlet solenoid valve, and the inlet solenoid valve are connected through a three-way ferrule joint. The outlet solenoid valve is communicated with an oil filling pipeline, and the inlet solenoid valve is communicated with a vacuum oil tank; The oil pump body includes a stainless steel telescopic corrugated component, an oil pump base, and an oil pump shield. The stainless steel pipe at the upper part of the stainless steel telescopic corrugated component passes through the hole on the oil pump base and is fixed to the oil pump base through a sealing component together with the oil pump shield, serving as the inlet; the upper end of the stainless steel pipe is connected to the vertically downward end of the three-way ferrule joint; the lower end surface of the stainless steel telescopic corrugated component is flush with the upper plane of the limiting ejector rod. The rod body of the limiting ejector rod passes through the lower hole of the oil pump shield and is fixed to the oil pump shield through a sealing component; a sealing ring is placed in the outer sealing groove of the oil pump base and is threadedly connected with the oil pump shield to form a sealed cavity; The first port of the pneumatic circuit switching three-way solenoid valve is connected to the oil pump shield through a quick connector, its second port is connected to the air outlet of the pressure control electro-hydraulic proportional valve, and its third port is connected to a vacuum negative pressure source; The air inlet of the pressure control electro-hydraulic proportional valve is connected to a positive pressure air source.

2. The pump oil device with adjustable speed in the vacuum pipeline according to claim 1, wherein, The top of the oil pump base is provided with a threaded through hole, and an axial sealing groove is arranged at the bottom of the through hole for fixing the stainless steel telescopic corrugated component; The bottom of the oil pump base is provided with threads and a sealing groove for connecting with the oil pump shield to form a sealed cavity.

3. The pump oil device with adjustable speed in the vacuum pipeline according to claim 2, characterized in that, The oil pump shield is in a cylindrical shape, and the stainless steel telescopic corrugated component and the limiting ejector rod are arranged inside the oil pump shield; the stainless steel pipe of the stainless steel telescopic corrugated component extends out of the top of the oil pump shield and is inserted into the through hole of the oil pump base; The bottom of the oil pump shield is provided with a threaded lower hole, and the rod body of the limiting ejector rod passes through the lower hole of the oil pump shield and is fixed through a sealing component; An installation through hole is arranged on the side of the oil pump shield near the lower hole for installing a quick connector.

4. The pump oil device with adjustable speed in the vacuum pipeline according to claim 3, characterized in that, The sealing component includes a U-shaped sealing ring, a through hole gasket, and a through hole fastener arranged in sequence. The bottom of the through hole fastener has threads, and the end of the through hole fastener has an external hexagon.

5. The oil pumping device with adjustable speed in the vacuum pipeline according to claim 1, characterized in that, The stainless steel telescopic corrugated component includes a semi-closed cavity and a stainless steel pipe. One end of the stainless steel pipe is connected to the opening of the semi-closed cavity, and the other end is inserted into the through hole of the oil pump base, serving as the only channel for the vacuum oil to enter and exit; The semi-closed cavity includes a telescopic stainless steel corrugated section, and the bottom of the semi-closed cavity is a plane for contacting the limiting ejector rod to limit the internal volume of the cavity.

6. The pump oil device with adjustable speed in the vacuum pipeline according to claim 5, characterized in that The stiffness range of the telescopic stainless steel corrugated section is 0.5 - 200 N / mm, the compression ratio range is 50 - 70%, and the tensile ratio range is 15 - 20%.

7. The pump oil device with adjustable speed in the vacuum pipeline according to claim 5, characterized in that, The limiting ejector rod is in a T shape, and the rod body of the limiting ejector rod extends out of the bottom of the oil pump shield and is fixed and sealed to limit the stretching position of the stainless steel telescopic corrugated component.

8. A method for pumping oil with adjustable speed in a vacuum pipeline, which is applied to the vacuum pipeline oil pumping device with adjustable speed as described in any one of claims 1 to 7, characterized in that, Comprising: When refueling, open the solenoid valve at the fuel inlet, close the solenoid valve at the fuel outlet, and switch the three-way solenoid valve for gas path to the negative pressure pipeline, so as to form a vacuum inside the oil pump guard. The internal and external pressure difference of the stainless steel telescopic corrugated component is converted into a natural stretching state, and the silicone oil in the vacuum oil tank flows from the vacuum oil tank into the internal cavity of the stainless steel telescopic corrugated component through the pipeline under the influence of gravity, realizing oil suction. When discharging oil, open the solenoid valve at the oil outlet, close the solenoid valve at the fuel inlet, and switch the three-way solenoid valve for gas path to the positive pressure pipeline. The pressure control electro-hydraulic proportional valve outputs according to the preset air pressure. Under the action of the pressure difference between the oil pump guard and the vacuum pipeline, the stainless steel telescopic corrugated component contracts, and the silicone oil inside it is extruded by the air pressure and enters the vacuum oil filling pipeline, realizing oil pumping.

9. The pump oil method with adjustable speed in the vacuum pipeline according to claim 8, characterized in that, By adjusting the output air pressure of the pressure control electro-hydraulic proportional valve, the pressure difference inside the oil pump guard can be adjusted, so as to achieve the purpose of changing the oil discharge speed.

10. The pump oil method with adjustable speed in the vacuum pipeline according to claim 8, characterized in that, By changing the end position of the limit ejector rod, the stretching position of the stainless steel telescopic corrugated component is changed, so as to achieve the purpose of adjusting the single oil pumping volume.

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