Electric constant pressure valve for oil and gas exploitation

Abstract

The electric constant pressure valve comprises a box body, a motor is fixedly installed on the box body, an output shaft of the motor penetrates through the wall of the box body to be connected with a speed reducing mechanism in the box body, the speed reducing mechanism is connected with a ball screw pair, the ball screw pair penetrates through the box body to be connected with an upper valve body, and the upper valve body is fixed to the bottom of the box body; the bottom of the upper valve body is connected with a lower valve body, a guide indicating device used for observing the on-off state and the opening degree of the constant pressure valve is arranged in the lower valve body, the bottom end of the lower valve body is fixedly connected with a base through a sealing clamping device, a valve ball used for controlling on-off of the constant pressure valve is arranged in the base, and a valve rod penetrates through the upper valve body, the lower valve body and the base. One end of the valve rod is connected with the ball screw pair, and the other end is connected with the valve ball. Automatic control over the constant pressure valve and accurate control over on-off and the opening degree of the constant pressure valve are achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas exploitation equipment, and particularly relates to an electric constant pressure valve for oil and gas exploitation. BACKGROUND

[0002] With the development of electromechanical integration, in the field of oil and gas exploitation technology, natural gas is produced through a gas production tree, needs to be reduced in pressure or adjusted in flow rate, that is, throttled and regulated in pressure, and then enters a gas gathering pipe network for transportation to a gas gathering station; in the natural gas exploitation process, throttling and pressure regulation is a very important process, and therefore, a throttling and pressure regulation component is also a very important process element; at present, a constant pressure valve is manually controlled for pressure regulation, and the randomness and suddenness in the operation process greatly excite the oil layer, and the control difficulty and labor intensity are large; since an oil and gas exploitation site is generally relatively remote, and the constant pressure valve is a high-strength sealing element, if a motor directly drives the valve rod to act, the existing constant pressure valve has low control precision and cannot meet the working requirements of high-precision pressure regulation. SUMMARY

[0003] The present application aims to provide an electric constant pressure valve for oil and gas exploitation, and to realize automatic control of the constant pressure valve and accurate control of the on-off state and opening degree of the constant pressure valve.

[0004] The technical scheme adopted by the present application is that the electric constant pressure valve for oil and gas exploitation comprises a box body, a motor fixedly installed on the box body, an output shaft of the motor penetrating a wall of the box body and connected with a speed reduction mechanism inside the box body, a ball screw pair connected with the speed reduction mechanism, the ball screw pair penetrating the box body and connected with an upper valve body, and the upper valve body fixed to a bottom of the box body.

[0005] The upper valve body is connected with a lower valve body, the lower valve body is provided with a guide indicating device for observing the on-off state and opening degree of the constant pressure valve, a base is fixedly connected to a bottom end of the lower valve body through a sealing clamping device, a valve ball for controlling the on-off state of the constant pressure valve is arranged in the base, a valve rod penetrates the upper valve body, the lower valve body and the base, one end of the valve rod is connected with the ball screw pair, and the other end of the valve rod is connected with the valve ball.

[0006] The present application has the following characteristics:

[0007] The ball screw pair comprises a screw rod, the screw rod penetrates the box body and is connected with the valve rod, a ball nut is sleeved outside the screw rod, and the ball nut is located at a top of the box body.

[0008] The speed reduction mechanism comprises an input shaft, an intermediate shaft and an output shaft arranged side by side inside the box body, both ends of the input shaft, the intermediate shaft and the output shaft are movably connected with an inner wall of the box body through bearings, the input shaft is a hollow shaft, and the screw rod penetrates an inside of the input shaft.

[0009] One end of the input shaft is connected with the output shaft of the motor, a pinion I is sleeved outside the input shaft, the pinion I is in meshing connection with a gear I sleeved outside the intermediate shaft, the upper end of the intermediate shaft is also sleeved with a pinion II, the pinion II is in meshing connection with a gear II sleeved on the output shaft, and the upper end of the output shaft is fixedly connected with the ball nut through the shaft coupling II.

[0010] The lower valve body is a hollow structure with a through slot in the middle part, and the upper and lower end faces of the valve body are respectively provided with a through hole for the valve rod to pass through and a threaded hole connected with the sealing clamping device, and the guiding and indicating device is located in the hollow structure inside the lower valve body.

[0011] The guiding and indicating device comprises a fixed sleeve and a scale plate, the fixed sleeve is located in the through slot in the middle part of the lower valve body and is sleeved outside the valve rod, a pointer is fixedly connected to the outer wall of the fixed sleeve and points to the scale line on the side wall of the scale plate, and the scale plate is in the form of a U-shaped plate and is buckled and fixed to the groove wall on one side of the through slot in the middle part of the lower valve body.

[0012] The sealing clamping device comprises a clamping sleeve, one end of the clamping sleeve is adaptively connected with the threaded hole of the lower valve body, and the other end is threadedly connected with the base, the center hole of the clamping sleeve is a stepped hole, the stepped hole comprises an upper positioning table and a lower positioning table, a packing ring is arranged between the upper positioning table and the lower positioning table, a spring is arranged between the packing ring and the lower positioning table, one end of the spring is fixedly connected with the packing ring, and the other end is fixedly connected with the lower positioning table, and the packing ring and the spring are sleeved outside the valve rod.

[0013] The lower end of the through slot of the lower valve body is provided with a clamping sleeve which is gap-fitted on the valve rod and is threadedly connected with the upper end of the stepped hole.

[0014] The base comprises an air inlet cavity and an air outlet cavity which are in the form of L-shaped structure and are rotationally symmetrical at a rotation angle of 90°, the left middle part of the air inlet cavity is provided with an air inlet threaded interface which is in communication with the air inlet cavity, the right middle part of the air outlet cavity is provided with an air outlet threaded interface which is in communication with the air outlet cavity,

[0015] A ball seat is arranged between the air inlet cavity and the air outlet cavity, the center of the ball seat is a spherical hole, trumpet mouths and straight holes which are in communication with the spherical hole are arranged at the two ends of the ball seat, the air inlet cavity and the air outlet cavity are in communication with the ball seat, a valve ball is located in the spherical hole of the ball seat, the lower end of the valve rod passes through the upper end of the air inlet cavity and is fixedly connected with the valve ball, and the valve ball is driven to ascend and descend by the valve rod, so that the air inlet cavity and the air outlet cavity are controlled to be in communication or not.

[0016] The air inlet cavity and the air outlet cavity are both in the form of L-shaped structure which is composed of a vertical cavity and annular cavities which are respectively located at the upper and lower ends of the ball seat and are in communication with the ball seat, and a plurality of through holes which are in communication with the vertical cavity are arranged on the cavity wall of the annular cavities.

[0017] The box body is fixedly connected by bolts and nuts, the upper end of the upper valve body is fixed to the bottom of the lower box body by bolts, and the bottom end of the upper valve body is fixedly connected with the top end of the lower valve body by threads.

[0018] The beneficial effects of this invention are:

[0019] (1) The electric pressure regulating valve of the present invention is used for oil and gas extraction. After multi-stage reduction by electric motor, deceleration mechanism and ball screw pair, the valve stem with valve ball connected at the lower end is driven to rise and fall according to the detection value of internal oil and gas pressure by detection device, so as to realize precise control of the opening and closing of pressure regulating valve and the opening degree. It solves the technical problems of unstable operation, low efficiency and low pressure control accuracy in the existing oil and gas extraction process. It can play a good pressure stabilization ability, improve working conditions and have good pressure reduction and stabilization effect.

[0020] (2) The electric pressure regulating valve for oil and gas extraction of the present invention has a guide indicator device connected to the valve stem on the lower valve body. During the valve stem raising and lowering process, the on / off state and opening degree of the pressure regulating valve can be read by the pointer that follows the valve stem raising and lowering and the scale plate that is fixed in position, so that the on / off state of the pressure regulating valve is clear at a glance.

[0021] (3) The electric pressure regulating valve for oil and gas extraction of the present invention adopts a multi-stage reduction structure composed of a reduction mechanism and a screw and nut pair, which converts the rotational motion of the motor into the linear motion of the valve stem. This is beneficial for the low-energy-consumption motor to provide a large thrust driving force to the valve stem, and provides conditions for the pressure regulating valve to be powered by solar energy. It is suitable for the working requirements of field environments where power is scarce.

[0022] (4) The electric pressure regulating valve of the present invention for oil and gas extraction can greatly reduce the power consumption of the pressure regulating valve by setting a spring for driving the valve stem to move down and reset after moving up. It will not cause crude oil to be transferred to the tank due to low back pressure. When the oil and gas pressure is unbalanced, the valve can also be automatically adjusted to play the role of pressure reduction and pressure stabilization. It has a compact structure and novel design, which can more effectively and quickly improve the pressure stabilization efficiency and pressure control accuracy of oil and gas pipelines.

[0023] (5) The electric pressure regulating valve of the present invention for oil and gas extraction provides a driving basis for the precise control of the pressure regulating valve by setting a detection device for detecting the internal oil and gas pressure value, which more effectively and quickly improves the pressure stabilization efficiency and pressure control accuracy of oil and gas pipelines. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the electric pressure regulating valve for oil and gas extraction according to the present invention;

[0025] Figure 2 This is a side view of the electric pressure regulating valve for oil and gas extraction according to the present invention.

[0026] Figure 3This is a cross-sectional view of AA in the electric pressure regulating valve for oil and gas extraction according to the present invention.

[0027] In the diagram, 1. Motor, 2. Ball screw pair, 2-1. Ball nut, 2-2. Screw, 3. Housing, 4. Base, 4-1. Inlet chamber, 4-2. Outlet chamber, 4-3. Inlet threaded interface, 4-4. Outlet threaded interface, 5. Guide indicator, 5-1. Fixing sleeve, 5-2. Pointer, 5-3. Scale plate, 6. Lower valve body, 7. Upper valve body, 8. Reduction mechanism, 8-1. Input shaft, 8-2. Output shaft, 8-3. Intermediate shaft, 8-4. Bearing, 8-5. Pinion I, 8-6. Large gear I, 8-7. Pinion II, 8-8. Large gear II, 9. Stepped hole, 10. Snap-fit ​​sleeve, 11. Coupling II, 12. Ball valve, 13. Spring, 14. Valve stem, 15. Coupling I, 16. Packing seal, 17. Compression sleeve, 18. Ball seat. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0029] Example 1

[0030] This invention relates to an electrically operated pressure regulating valve for oil and gas extraction, such as... Figure 1 As shown, it includes a housing 3, on which a motor 1 is fixedly installed. The output shaft of the motor 1 passes through the wall of the housing 3 and is connected to a reduction mechanism 8 inside the housing 3. The reduction mechanism 8 is connected to a ball screw pair 2. The ball screw pair 2 passes through the housing 3 and is connected to an upper valve body 7. The upper valve body 7 is fixed to the bottom of the housing 3.

[0031] The lower valve body 6 is connected to the bottom of the upper valve body 7. The lower valve body 6 contains a guide indicator 5 for observing the on / off status and opening degree of the pressure regulating valve. A base 4 is fixed to the bottom of the lower valve body 6 via a sealing snap-fit ​​device. A valve ball 12, which controls the on / off state of the pressure regulating valve, is located inside the base 4. A valve stem 14 runs through the upper valve body 7, lower valve body 6, and base 4. One end of the valve stem 14 is connected to a ball screw assembly 2, and the other end is connected to the valve ball 12. The on / off control of the pressure regulating valve is achieved by the up-and-down movement of the valve stem 14, which drives the valve ball to move synchronously.

[0032] Furthermore, the lower valve body 6 is a hollow structure with a through groove in the middle, and the upper and lower end faces of the valve body 6 are respectively provided with through holes for the valve stem 14 to pass through and threaded holes for connecting with the sealing snap-fit ​​device. The guide indicator device 5 is located inside the hollow structure of the lower valve body 6.

[0033] The guide indicator 5 includes a fixed sleeve 5-1 and a scale plate 5-3. The fixed sleeve 5-1 is located in the through groove in the middle of the lower valve body 6 and is sleeved on the outside of the valve stem 14. A pointer 5-2 is fixed on the outer wall of the fixed sleeve 5-1 and points to the scale line on the side wall of the scale plate 5-3. The scale plate 5-3 has a U-shaped plate structure and is fastened and fixed to the groove wall on one side of the through groove in the middle of the lower valve body 6.

[0034] When the valve stem 14 rises and falls, it causes the pointer 5-2 on the fixed sleeve 5-1 to move up and down. The on / off state and opening size of the pressure regulating valve can be read through the engraving on the scale plate 5-3. In the above structure, by setting a guide indicator 5 connected to the valve stem 14 on the lower valve body 6, the on / off state and opening size of the pressure regulating valve can be read by the pointer 5-2 that follows the rise and fall of the valve stem 14 and the scale plate 5-3 that is fixed in position during the rise and fall of the valve stem 14. This makes the on / off state of the pressure regulating valve clear at a glance.

[0035] Example 2

[0036] Based on Example 1, such as Figure 2 and Figure 3 As shown, the ball screw assembly 2 in the electric pressure regulating valve for oil and gas extraction of the present invention includes a screw 2-2, which passes through the housing 3 and is connected to the valve stem 14. A ball nut 2-1 is sleeved on the outside of the screw 2-2, and the ball nut 2-1 is located at the top of the housing 3.

[0037] Furthermore, the reduction mechanism 8 includes an input shaft 8-1, an intermediate shaft 8-3, and an output shaft 8-2 located side by side inside the housing 3. The two ends of the input shaft 8-1, the intermediate shaft 8-3, and the output shaft 8-2 are movably connected to the inner wall of the housing 3 through bearings 8-4. The input shaft 8-1 is a hollow shaft, and the lead screw 2-2 passes through the inside of the input shaft 8-1.

[0038] One end of the input shaft 8-1 is connected to the output shaft of the motor 1. A small gear I 8-5 is sleeved on the outside of the input shaft 8-1. The small gear I 8-5 meshes with the large gear I 8-6 sleeved on the outside of the intermediate shaft 8-3. A small gear II 8-7 is also sleeved on the upper end of the intermediate shaft 8-3. The small gear II 8-7 meshes with the large gear II 8-8 sleeved on the output shaft 8-2. The upper end of the output shaft 8-2 is fixedly connected to the ball nut 2-1 through the coupling II 11.

[0039] The input shaft 8-1 is driven by the motor 1 to rotate. The input shaft 8-1 drives the intermediate shaft 8-3 and the output shaft 8-2 to rotate in sequence. The rotational motion is converted into linear motion of the ball screw 2 and the valve stem 14 fixedly connected to the ball screw 2-2 through the ball screw pair 2 connected to the output shaft 8-2 of the reduction mechanism. The valve ball 12 is fixed at the lower end of the valve stem 14. The valve is opened and closed by the up and down movement of the valve stem 14.

[0040] Example 3

[0041] This invention relates to an electrically operated pressure regulating valve for oil and gas extraction, such as... Figure 3 As shown, it includes a housing 3, an upper valve body 7 fixed to the bottom of the housing 3, a lower valve body 6 detachably fixed to the lower end of the upper valve body 7, and a base 4 sealed and fixed to the lower end of the lower valve body 6 by a sealing snap-fit ​​device.

[0042] The housing 3 houses a reduction gear mechanism 8, which is fixed to the housing 3. The output shaft of the motor 1 is fixedly connected to the input shaft 8-1 of the reduction gear mechanism 8 via coupling I 15. The upper end of the output shaft 8-2 of the reduction gear mechanism is fixedly connected to the ball nut 2-1 of the ball screw pair 2 via coupling II 11. The lower end of the valve stem 14 is fixedly connected to a valve ball 12 located in the base 4, which controls the opening and closing of the air inlet chamber 4-1 and the air outlet chamber 4-2 by raising or lowering the valve stem 14. After being elastically positioned and connected to the sealing snap-fit ​​device, the valve stem 14 is adapted to and connected to the guide indicator device 5 located on the lower valve body 6.

[0043] The lower end of the ball screw 2-2 in the ball screw pair 2 passes through the hollow structure output shaft 8-2 and is fixedly connected to the upper end of the valve stem 14 that extends into the upper valve body 7. The oil and gas pipe connected to the air inlet chamber 4-1 is equipped with a detection device for detecting the internal oil and gas pressure value. After the motor 1 starts or stops according to the pressure value detected by the detection device, it realizes the precise control of the opening and closing of the pressure regulating valve and the opening degree after the valve ball 12 rises and falls.

[0044] Specifically, the detection device uses a pneumatic pressure sensor or an oil pressure sensor. In the above structure, after multi-stage reduction by the motor 1 in conjunction with the reduction mechanism and the ball screw pair 2, the valve stem with the lower end connected to the valve ball is driven to rise and fall according to the detection value of the internal oil and gas pressure by the detection device, so as to achieve precise control of the opening and closing of the pressure regulating valve and the opening degree. This solves the technical problems of unstable operation, low efficiency and low pressure control accuracy in the existing oil and gas extraction process. It can play a good pressure stabilization role, improve working conditions and have a good pressure reduction and stabilization effect.

[0045] The reduction mechanism 8 includes an input shaft 8-1, an intermediate shaft 8-3, and an output shaft 8-2, which are rotatably supported in the housing 3 via bearings 8-4. A small gear I 8-5 fixed on the input shaft 8-1 meshes with a large gear I 8-6 fixed on the intermediate shaft 8-3, and a small gear II 8-7 fixed on the intermediate shaft 8-3 meshes with a large gear II 8-8 fixed on the output shaft 8-2.

[0046] The sealing and snapping device includes a ferrule 17, a packing seal ring 16, and a spring 13. The lower valve body 6 is a hollow structure with a through groove in the middle. The upper and lower end faces of the lower valve body 6 are respectively provided with through holes for the valve stem 14 to pass through and threaded holes for connecting with the upper end of the ferrule 17. After the upper and lower ends of the ferrule 17 are adapted and connected to the threaded holes at the lower end of the lower valve body 6 and the upper end of the base 4, the lower valve body 6 and the base 4 with their end faces in contact are fixed together as one.

[0047] Furthermore, the center hole of the ferrule 17 is a stepped hole 9, and the spring 13 fitted on the valve stem 14 and the packing seal ring 16 fixed to the upper end of the spring 13 and fixed to the valve stem 14 are located between the upper positioning platform and the lower positioning platform of the stepped hole 9. The lower end of the through groove of the lower valve body 6 is provided with a snap-fit ​​sleeve 10 that is clearance-fitted to the valve stem 14 and threadedly fixed to the upper end of the stepped hole 9. When the lead screw 2-2 drives the valve stem 14 to move upward, the valve ball 12 controls the opening of the pressure regulating valve, causing the spring 13 fixed to the lower positioning platform of the stepped hole 9 to be stretched and stored.

[0048] By setting a spring 13 to drive the valve stem 14 to move down and reset after moving up, the spring force of the valve stem 14 after moving up can be provided to move down, which can greatly reduce the power consumption of the pressure regulating valve and prevent crude oil from being transferred due to low back pressure and high back pressure. When the oil and gas pressure is unbalanced, the valve can also be automatically adjusted to reduce pressure and stabilize pressure. The structure is compact and the design is novel, which can more effectively and quickly improve the pressure stabilization efficiency and pressure control accuracy of oil and gas pipelines.

[0049] The guide indicator 5 includes a fixed sleeve 5-1 and a scale plate 5-3. The fixed sleeve 5-1 is located in the through groove in the middle of the lower valve body 6 and is sleeved on the outside of the valve stem 14. A pointer 5-2 is fixed on the outer wall of the fixed sleeve 5-1 and points to the scale line on the side wall of the scale plate 5-3. The scale plate 5-3 has a U-shaped plate structure and is fastened and fixed to the groove wall on one side of the through groove in the middle of the lower valve body 6.

[0050] The base 4 includes an L-shaped air inlet chamber 4-1 and an air outlet chamber 4-2 arranged symmetrically at a 90° rotation angle. An air inlet threaded interface 4-3 is provided in the left middle part of the air inlet chamber 4-1, and the air inlet threaded interface 4-3 communicates with the air inlet chamber 4-1. An air outlet threaded interface 4-4 is provided in the right middle part of the air outlet chamber 4-2, and the air outlet threaded interface 4-4 communicates with the air outlet chamber 4-2.

[0051] A ball seat 18 is provided between the air intake chamber 4-1 and the air outlet chamber 4-2. The ball seat 18 has a spherical hole at its center, and the two ends of the ball seat 18 have flared mouths and straight holes that communicate with the spherical hole. The air intake chamber 4-1 and the air outlet chamber 4-2 are connected to the ball seat 18. The valve ball 12 is located in the spherical hole of the ball seat 18. The lower end of the valve stem 14 passes through the upper end of the air intake chamber 4-1 and is fixedly connected to the valve ball 12. The valve stem 14 drives the valve ball 12 to rise and fall, thereby realizing the on / off control of the air intake chamber 4-1 and the air outlet chamber 4-2.

[0052] Furthermore, both the intake chamber 4-1 and the exhaust chamber 4-2 are composed of a vertical cavity and an annular cavity located at the upper and lower ends of the ball seat 18 and connected to the ball seat 18, forming an L-shaped structure. The annular cavity has multiple through holes on its wall that are connected to the vertical cavity.

[0053] Furthermore, the housing 3 is fixedly connected to the upper housing and the lower housing by bolts and nuts, the upper end of the upper valve body 7 is fixed to the bottom of the lower housing by bolts, and the bottom end of the upper valve body 7 is fixed to the top end of the lower valve body 6 by threaded connection.

[0054] This invention relates to an electric pressure regulating valve for oil and gas extraction. A DC motor 1 drives a two-stage reduction mechanism to rotate the valve. The rotational motion is converted into linear motion by a ball screw pair 2 connected to the output shaft 8-2 of the reduction mechanism, and a valve stem 14 fixedly connected to the ball screw 2-2. A valve ball 12 is fixed to the lower end of the valve stem 14. The valve opens and closes as the valve stem 14 moves up and down. When the bottom oil and gas pressure is too high, the motor 1 rotates forward to control the valve ball 12 to move upward, connecting the inlet chamber 4-1 and the outlet chamber 4-2, opening the valve and stabilizing the oil and gas pressure. When the pressure drops, the spring 13 stretches and stores energy. The spring 13 releases energy to assist the valve stem 14 downward, and the motor 1 reverses to close the valve. This prevents back pressure from high pressure due to low sleeve pressure, thus avoiding crude oil spillage. The valve can also automatically adjust when the oil and gas pressure is unbalanced, thus reducing and stabilizing the pressure.

Claims

1. An electrically powered constant pressure valve for oil and gas production, characterized in that The utility model provides a kind of constant pressure valve, including box (3), motor (1) is fixedly installed on the box (3), the output shaft of motor (1) passes through the wall of box (3) and is connected with the reduction mechanism (8) inside box (3), ball screw pair (2) is connected with the reduction mechanism (8), ball screw pair (2) is connected with upper valve body (7) passing through box (3), and upper valve body (7) is fixed to the bottom of box (3); The bottom of the upper valve body (7) is connected with the lower valve body (6), the lower valve body (6) is provided with a guide indicating device (5) for observing the on-off state and opening of the constant pressure valve, and the bottom end of the lower valve body (6) is fixedly connected with the base (4) through a sealing clamping device. The base (4) is provided with a valve ball (12) for controlling the on-off of the constant pressure valve. The upper valve body (7), the lower valve body (6), and the base (4) are internally penetrated by a valve rod (14). One end of the valve rod (14) is connected with the ball screw pair (2), and the other end is connected with the valve ball (12).

2. The electrically powered constant pressure valve for oil and gas extraction according to claim 1, characterized in that, The ball screw pair (2) includes a lead screw (2-2) that is connected with the valve rod (14) by penetrating the box (3). The lead screw (2-2) is externally sleeved with a ball nut (2-1), and the ball nut (2-1) is located at the top of the box (3).

3. The electrically powered constant pressure valve for oil and gas extraction according to claim 2, characterized in that, The reduction mechanism (8) includes an input shaft (8-1), an intermediate shaft (8-3), and an output shaft (8-2) that are arranged side by side inside the box (3). The two ends of the input shaft (8-1), the intermediate shaft (8-3), and the output shaft (8-2) are movably connected with the inner wall of the box (3) through bearings (8-4). The input shaft (8-1) is a hollow shaft, and the lead screw (2-2) penetrates the inside of the input shaft (8-1). One end of the input shaft (8-1) is connected with the output shaft of the motor (1). A pinion I (8-5) is sleeved on the outside of the input shaft (8-1). The pinion I (8-5) is meshingly connected with a large gear I (8-6) that is sleeved on the outside of the intermediate shaft (8-3). The upper end of the intermediate shaft (8-3) is also sleeved with a pinion II (8-7). The pinion II (8-7) is meshingly connected with a large gear II (8-8) that is sleeved on the output shaft (8-2). The upper end of the output shaft (8-2) is fixedly connected with the ball nut (2-1) through a coupling II (11).

4. The electrically powered constant pressure valve for oil and gas extraction of claim 1, wherein, The lower valve body (6) is a hollow structure with a through groove in the middle. The upper and lower end faces of the lower valve body (6) are respectively provided with through holes for the valve rod (14) to pass through and threaded holes connected with the sealing clamping device. The guide indicating device (5) is located in the hollow structure inside the lower valve body (6).

5. The electrically powered constant pressure valve for oil and gas extraction according to claim 4, characterized in that, The guide indicating device (5) includes a fixed sleeve (5-1) and a scale plate (5-3). The fixed sleeve (5-1) is located in the through groove in the middle of the lower valve body (6) and is sleeved on the outside of the valve rod (14). The outer wall of the fixed sleeve (5-1) is fixedly connected with a pointer (5-2) that points to the graduation line on the side wall of the scale plate (5-3). The scale plate (5-3) is in the shape of a U-shaped plate and is fixedly buckled on the groove wall on one side of the through groove in the middle of the lower valve body (6).

6. The electrically powered constant pressure valve for oil and gas extraction of claim 4, wherein, The sealing clamping device comprises a clamping sleeve (17) which is connected with the threaded hole of the lower valve body (6) at one end and is screwed with the base (4) at the other end, the central hole of the clamping sleeve (17) is a stepped hole (9), the stepped hole (9) comprises an upper positioning platform and a lower positioning platform, a packing ring (16) is arranged between the upper positioning platform and the lower positioning platform, a spring (13) is arranged between the packing ring (16) and the lower positioning platform, one end of the spring (13) is fixedly connected with the packing ring (16), and the other end is fixedly connected with the lower positioning platform, and the packing ring (16) and the spring (13) are sleeved on the outer side of the valve rod (14); The lower end of the through slot of the lower valve body (6) is provided with a clamping sleeve (10) which is gap-fitted on the valve rod (14) and is screw-connected with the upper end of the stepped hole (9).

7. The electrically powered constant pressure valve for oil and gas extraction according to claims 1-6, characterized in that, The base (4) comprises an air inlet cavity (4-1) and an air outlet cavity (4-2) which are arranged in an L-shaped structure and are rotationally symmetrical at a rotation angle of 90°, a left middle part of the air inlet cavity (4-1) is provided with an air inlet threaded interface (4-3) which is communicated with the air inlet cavity (4-1), a right middle part of the air outlet cavity (4-2) is provided with an air outlet threaded interface (4-4) which is communicated with the air outlet cavity (4-2), A ball seat (18) is arranged between the air inlet cavity (4-1) and the air outlet cavity (4-2), the center of the ball seat (18) is a spherical hole, and trumpet mouths and straight holes which are communicated with the spherical hole are opened at both ends of the ball seat (18), the air inlet cavity (4-1) and the air outlet cavity (4-2) are communicated with the ball seat (18), the valve ball (12) is located in the spherical hole of the ball seat (18), the lower end of the valve rod (14) passes through the upper end of the air inlet cavity (4-1) and is fixedly connected with the valve ball (12), and the valve ball (12) is driven to ascend and descend by the valve rod (14), so that the air inlet cavity (4-1) and the air outlet cavity (4-2) are controlled to be connected or disconnected.

8. The electrically powered constant pressure valve for oil and gas extraction according to claim 7, characterized in that, The air inlet cavity (4-1) and the air outlet cavity (4-2) each comprise an L-shaped structure composed of a vertical cavity and annular cavities which are located at the upper and lower ends of the ball seat (18) and are communicated with the ball seat (18), and a plurality of through holes which are communicated with the vertical cavity are arranged on the cavity wall of the annular cavities.

9. The electrically powered constant pressure valve for oil and gas extraction of claim 1, wherein, The box body (3) is fixedly connected by bolts and nuts, the upper end of the upper valve body (7) is fixed to the bottom of the lower box body by bolts, and the bottom end of the upper valve body (7) is fixedly connected with the top end of the lower valve body (6) by threads.

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