阅读说明：本技术 一种高低压先导阀及管道高低压紧急切断装置 (High-low pressure pilot valve and high-low pressure emergency cut-off device for pipeline ) 是由 不公告发明人 于 2021-08-23 设计创作，主要内容包括：本发明公开了一种高低压先导阀及管道高低压紧急切断装置,高低压先导阀包括高低压控制箱体,高低压控制箱体通过先导壳体与管线相连接,高低压控制箱体与先导壳体之间设有高压活塞和低压活塞,高压活塞一端设有高压控制弹簧,低压活塞一端设有低压控制弹簧,低压活塞和高压活塞分别与牵引锁摆杆相接触。管道高低压紧急切断装置包括高低压先导阀和主阀,主阀两侧分别连接上游管线和下游管线,高低压先导阀与下游管线相连接,高低压先导阀中牵引锁摆杆通过牵引锁连接在锁止机构上,锁止机构连接在助力机构上,助力机构连接在主阀上。本发明可手动和远程切断、相应速度快、复位简单便捷、无需额外能源、无需气液转换装置、结构简单、安全可靠。(The invention discloses a high-low pressure pilot valve and a high-low pressure emergency cutting device for a pipeline. The high-low pressure emergency cutoff device for the pipeline comprises a high-low pressure pilot valve and a main valve, wherein upstream pipelines and downstream pipelines are connected to two sides of the main valve respectively, the high-low pressure pilot valve is connected with the downstream pipelines, a traction lock swing rod in the high-low pressure pilot valve is connected to a locking mechanism through a traction lock, the locking mechanism is connected to a power-assisted mechanism, and the power-assisted mechanism is connected to the main valve. The invention can be manually and remotely cut off, has high corresponding speed, simple and convenient reset, simple and reliable structure, no additional energy source and no gas-liquid conversion device.)

1. The utility model provides a high low pressure pilot valve, its characterized in that includes high pressure control box, low pressure control box and guide's casing, guide's casing includes high pressure guide's casing and low pressure guide's casing, the high pressure control box passes through high pressure guide's casing and connects on the pipeline, the low pressure control box passes through low pressure guide's casing and connects on the pipeline, be provided with high-pressure piston between high pressure control box and the high pressure guide's casing, the one end of high-pressure piston is equipped with the high pressure and holds the unit of doing all can, be provided with the low pressure piston between low pressure control box and the low pressure guide's casing, the one end of low pressure piston is equipped with the low pressure and holds the unit of doing all can, low pressure piston and high pressure piston contact with traction lock pendulum rod respectively.

2. The high-low pressure pilot valve as claimed in claim 1, wherein the high pressure power accumulating unit is a high pressure control spring or a high pressure slender rod, the high pressure control spring is fixed on the high pressure control box body through an adjusting nut, and the high pressure slender rod is fixed with the high pressure control box body through a high pressure slender rod clamp.

3. A high and low pressure pilot valve as claimed in claim 1, wherein a low pressure elongate rod cage is provided below the low pressure pilot housing, the low pressure piston extends into the low pressure elongate rod cage through the low pressure pilot housing, a low pressure elongate rod is fastened to the other end of the low pressure piston, and the low pressure elongate rod is fixed to the low pressure elongate rod cage by a low pressure elongate rod holder.

4. A high and low pressure pilot valve as claimed in claim 2, wherein the low pressure power accumulating unit is a low pressure control spring fixed on a low pressure control box body by an adjusting nut.

5. The high-low pressure pilot valve is characterized by comprising a high-low pressure control box body, wherein the high-low pressure control box body is connected with a pipeline through a pilot shell, a high-pressure piston and a low-pressure piston are arranged between the high-low pressure control box body and the pilot shell, one end of the high-pressure piston is provided with a high-pressure control spring, one end of the low-pressure piston is provided with a low-pressure control spring, and the low-pressure piston and the high-pressure piston are respectively contacted with a traction lock swing rod.

6. A high and low pressure pilot valve as claimed in claim 5, wherein the high pressure piston is nested outside the low pressure piston and the high pressure control spring is nested outside the low pressure control spring; or the low-pressure piston is nested outside the high-pressure piston, and the low-pressure control spring is nested outside the high-pressure control spring.

7. A high and low pressure pilot valve as claimed in any one of claims 1 to 6, wherein a shut-off valve is provided between the pilot housing and the line.

8. A high-low pressure emergency cut-off device for a pipeline is characterized by comprising a high-low pressure pilot valve and a main valve according to any one of claims 1 to 7, wherein two sides of the main valve are respectively connected with an upstream pipeline and a downstream pipeline, the high-low pressure pilot valve is connected with the downstream pipeline, a traction lock swing rod in the high-low pressure pilot valve is connected with a locking mechanism through a traction lock, the locking mechanism is connected with a power-assisted mechanism, and the power-assisted mechanism is connected with the main valve.

9. The high-low pressure emergency cut-off device for the pipeline as claimed in claim 8, wherein the locking mechanism comprises a locking mechanism box, two locking swing arms and a locking element, one end of each locking swing arm is locked with the spring pull rod of the power assisting mechanism, the other end of each locking swing arm is in contact with the locking element through a locking swing arm bearing, and the locking element is connected with the traction lock.

10. The emergency pipeline disconnection device as claimed in claim 8, wherein the locking mechanism comprises a locking mechanism housing and a locking element, one end of the locking element is axially fixed in the locking mechanism housing, the other end of the locking element is provided with a locking element bearing, the locking element bearing is in contact with one end of a slider guide groove, the other end of the slider guide groove is axially fixed in the locking mechanism housing, a slider is arranged in the slider guide groove, the slider is mounted at the tail end of a spring pull rod of the boosting mechanism, and the locking element is connected with the traction lock.

11. The high-low pressure emergency cutoff device for pipelines according to claim 9, characterized in that the power-assisted mechanism is an angular travel power-assisted mechanism, the angular travel power-assisted mechanism comprises a power-assisted mechanism box, a spring pull rod is arranged in the power-assisted mechanism box, a power-assisted spring is sleeved on the spring pull rod, a shifting fork roller is installed on the spring pull rod, a shifting fork is arranged on the shifting fork roller, the shifting fork is connected to a main valve, and the locking swing arm is used for maintaining the deformation state of the spring.

12. The high-low pressure emergency pipeline cutting device of claim 9, wherein the power-assisted mechanism comprises a power-assisted mechanism box, a spring pull rod is arranged in the power-assisted mechanism box, a power-assisted spring is sleeved on the spring pull rod, a rack is mounted on the spring pull rod, the rack is matched with a gear, the gear is connected to the main valve, and the locking swing arm is used for maintaining the deformation state of the spring.

13. The high-low pressure emergency pipeline cutting device of claim 10, wherein the power-assisted mechanism is a linear travel power-assisted mechanism, and comprises a power-assisted mechanism box body, a spring pull rod is arranged in the power-assisted mechanism box body, a power-assisted spring is sleeved on the spring pull rod, the spring is compressed between the power-assisted mechanism box body and the spring pull rod, and the spring pull rod is connected with the main valve.

14. The high-low pressure emergency pipeline cutting device of claim 11 or 12, wherein the power-assisted mechanism is provided with a reset mechanism, the reset mechanism comprises a hand wheel and a lead screw, and the lead screw is connected with the spring pull rod.

15. The high-low pressure emergency cut-off device for the pipeline according to any one of claims 11 or 12, wherein the power-assisted mechanism is provided with a reset mechanism, the reset mechanism comprises an oil storage tank, a manual pump and a hydraulic pipeline, the hydraulic pipeline is provided with the manual pump, one end of the hydraulic pipeline is located in the oil storage tank, a first section of the hydraulic pipeline is connected with the hydraulic cylinder, and the power-assisted mechanism box body and the top end of the spring pull rod form the hydraulic cylinder.

Technical Field

The invention relates to a natural gas wellhead safety guarantee technology, in particular to a high-low pressure pilot valve and a pipeline high-low pressure emergency cut-off device.

Background

The wellhead emergency cut-off device is a safety guarantee of a natural gas wellhead, and is automatically closed when the pressure of a wellhead medium exceeds a set high limit pressure, so that downstream equipment is prevented from being damaged due to pressure overload; when the pressure of the medium at the wellhead is lower than the set low limit pressure, the wellhead emergency cut-off device is automatically closed, and system equipment is prevented from being damaged.

The main emergency cut-off valves in the current market have three structures of mechanical self-operated type, electromagnetic type and hydraulic self-operated type, wherein the electromagnetic type emergency cut-off valves are limited by the installation site environment, only have low voltage sources of about 12V on site, so that the electromagnetic valves can not provide larger thrust, and only can narrow the flow channels of the valves, thereby leading the flow resistance of the valves to be extremely large, being easy to freeze in winter and leading the valves to be incapable of acting; the hydraulic self-operated emergency cut-off valve is large in installation volume, large pipeline air pressure needs to be converted into small oil circuit hydraulic pressure by most of the hydraulic self-operated emergency cut-off valves, the structure is complex, installation and maintenance are inconvenient, reaction is slow, and the condition that hydraulic oil is lack of pressure due to leakage exists.

CN201710929204.7 discloses a natural gas well head emergency cut-off device, including assist drive device, trigger mechanism and valve, trigger mechanism includes blasting needle type control mechanism and locking mechanism, and blasting needle type control mechanism includes two kinds of trigger states of overpressure control and insufficient pressure control, and arbitrary one triggers the state homoenergetic and makes locking mechanism remove, and locking mechanism drives assist drive device control valve break-make. The blasting needle type control mechanism of the technical scheme cannot be reset in time after being triggered, and remote control is difficult to realize.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a high-low pressure pilot valve and a pipeline high-low pressure emergency cut-off device which can be manually and remotely cut off, has high corresponding speed, simple and convenient reset, no need of additional energy sources and gas-liquid conversion devices, simple structure, safety and reliability.

The purpose of the invention is realized by the following technical scheme.

The utility model provides a high low pressure pilot valve, includes high pressure control box, low pressure control box and guide's casing, guide's casing includes high pressure guide's casing and low pressure guide's casing, the high pressure control box passes through high pressure guide's casing and connects on the pipeline, the low pressure control box passes through low pressure guide's casing and connects on the pipeline, be provided with the high pressure piston between high pressure control box and the high pressure guide's casing, the one end of high pressure piston is equipped with the high pressure and holds the unit of holding power, be provided with the low pressure piston between low pressure control box and the low pressure guide's casing, the one end of low pressure piston is equipped with the low pressure and holds the unit of holding power, low pressure piston and high pressure piston contact with traction lock pendulum rod respectively.

Furthermore, the high-pressure power storage unit is a high-pressure control spring or a high-pressure slender rod, the high-pressure control spring is fixed on the high-pressure control box body through an adjusting nut, and the high-pressure slender rod is fixed with the high-pressure control box body through a high-pressure slender rod clamp.

Further, low pressure guide casing below is equipped with low pressure slender rod pole cage, the low pressure piston passes in low pressure guide casing extends to low pressure slender rod pole cage, the other end fastening of low pressure piston has low pressure slender rod, low pressure slender rod passes through low pressure slender rod holder and fixes mutually with low pressure slender rod pole cage.

Furthermore, the low-pressure power storage unit is a low-pressure control spring which is fixed on the low-pressure control box body through an adjusting nut.

The utility model provides a high-low pressure pilot valve, includes high-low pressure control box, high-low pressure control box is connected with the pipeline through guide's casing, be equipped with high-pressure piston and low pressure piston between high-low pressure control box and the guide's casing, high-pressure piston one end is equipped with the high pressure control spring, low pressure piston one end is equipped with the low pressure control spring, low pressure piston and high pressure piston contact with traction lock pendulum rod respectively.

Further, the high-pressure piston is nested outside the low-pressure piston, and the high-pressure control spring is nested outside the low-pressure control spring; or the low-pressure piston is nested outside the high-pressure piston, and the low-pressure control spring is nested outside the high-pressure control spring.

Furthermore, a stop valve is arranged between the pilot housing and the pipeline.

A high-low pressure emergency cut-off device for a pipeline, comprising a high-low pressure pilot valve and a main valve according to any one of claims 1 to 7, wherein the two sides of the main valve are respectively connected with an upstream pipeline and a downstream pipeline, the high-low pressure pilot valve is connected with the downstream pipeline, a traction lock swing rod in the high-low pressure pilot valve is connected with a locking mechanism through a traction lock, the locking mechanism is connected with a power-assisted mechanism, and the power-assisted mechanism is connected with the main valve.

Furthermore, locking mechanism includes locking mechanism box, two locking swing arms and a locking component, the one end of two locking swing arms all locks mutually with assist drive device's spring pull rod, the other end of two locking swing arms contacts with the locking component through locking swing arm bearing, the locking component with pull the lock phase and be connected.

Furthermore, locking mechanism includes locking mechanism box and locking component, the one end axial fixity of locking component is in the locking mechanism box, and the other end is equipped with the locking component bearing, the locking component bearing contacts with the one end of slider guide slot, the other end axial fixity of slider guide slot is in the locking mechanism box, establish the slider in the slider guide slot, the slider is installed at assist drive device's spring pull rod end, the locking component is connected with the phase lock that pulls.

Further, assist drive device is angle stroke assist drive device, angle stroke assist drive device includes the assist drive device box, be equipped with the spring pull rod in the assist drive device box, the cover has the helping hand spring on the spring pull rod, install the fork roller bearing of pulling out on the spring pull rod, it pulls out the fork to be equipped with on the fork roller bearing of pulling out, it connects on the main valve to pull out the fork, the locking swing arm is used for maintaining the deformation state of spring.

Further, assist drive device includes the assist drive device box, be equipped with the spring pull rod in the assist drive device box, the cover has the helping hand spring on the spring pull rod, install the rack on the spring pull rod, the rack cooperatees with the gear, gear connection is on the main valve, the locking swing arm is used for maintaining the deformation state of spring.

Further, assist drive device is straight line stroke assist drive device, including the assist drive device box, be equipped with the spring pull rod in the assist drive device box, the cover has helping hand spring on the spring pull rod, the spring compression is between assist drive device box and spring pull rod, the spring pull rod is connected with the main valve.

Furthermore, a reset mechanism is arranged on the power-assisted mechanism and comprises a hand wheel and a screw rod, and the screw rod is connected with the spring pull rod.

Further, be equipped with canceling release mechanical system on the assist drive device, canceling release mechanical system includes batch oil tank, hand pump, hydraulic pressure pipeline, install the hand pump on the hydraulic pressure pipeline, the one end of hydraulic pressure pipeline is located the batch oil tank, the first section of hydraulic pressure pipeline is connected with the pneumatic cylinder, the assist drive device box constitutes the pneumatic cylinder with spring pull rod top.

Compared with the prior art, the invention has the advantages that: the full-path direct-current structure is designed, manual cutting can be performed in emergency, remote cutting can be realized, response speed is high, cutting-off time is less than or equal to 2s, resetting is simple and convenient, resetting is performed within 2 minutes, public energy sources such as electric power and gas sources are not needed, the structure is simple, safety and reliability are realized, a hydraulic or nitrogen control system is not needed, the condition that hydraulic oil or nitrogen is lack of pressure due to leakage does not exist, medium gas cannot be discharged into the atmosphere, influence on environment and safety is not generated, the medium gas cannot enter a control chamber, and influence on product performance and function due to impurities contained in the medium gas is avoided.

Drawings

Fig. 1 is a schematic structural diagram of embodiment 1 of the present invention.

Fig. 2 is a schematic structural diagram of embodiment 2 of the present invention.

Fig. 3 is a schematic structural diagram of embodiment 3 of the present invention.

Fig. 4 is a schematic structural diagram of embodiment 4 of the present invention.

FIG. 5 is a schematic diagram of the normal operation condition of embodiment 5 of the present invention.

Fig. 6 is a schematic view of an under-voltage cutoff condition in embodiment 5 of the present invention.

Fig. 7 is a schematic view of an overpressure cutoff condition in embodiment 5 of the present invention.

Fig. 8 is a schematic structural view of a locking mechanism in embodiment 5 of the present invention.

Fig. 9 is a schematic structural view of a power assisting mechanism in embodiment 5 of the present invention.

Fig. 10 is a schematic structural view of a reset mechanism in embodiment 5 of the present invention.

Fig. 11 is a schematic structural view of a power assisting mechanism in embodiment 6 of the present invention.

Fig. 12 is a schematic structural view of a locking mechanism according to embodiment 7 of the present invention.

FIG. 13 is a schematic diagram of the normal operation condition of embodiment 7 of the present invention.

FIG. 14 is a schematic view of an under-pressure or over-pressure cut-off condition in accordance with embodiment 7 of the present invention.

Fig. 15 is a schematic structural view of a reset mechanism in embodiment 8 of the present invention.

In the figure: 1. the main valve 2, the high-low pressure pilot valve 3, the locking mechanism 4, the boosting mechanism 5, the reset mechanism 6, the upstream pipeline 7, the downstream pipeline 201, the cut-off valve 202, the pilot housing 203, the high-pressure piston 204, the low-pressure piston 205, the high-low pressure control box 206, the high-pressure control spring 207, the low-pressure control spring 208, the traction lock pendulum rod 209, the high-pressure pilot housing 210, the high-pressure control box 211, the low-pressure pilot housing 212, the low-pressure control box 213, the high-pressure slender rod 214, the high-pressure slender rod clamp 215, the low-pressure slender rod cage 216, the low-pressure slender rod 217, the low-pressure slender rod clamp 301, the traction lock 302, the locking mechanism box 303, the locking element 304, the locking swing arm bearing 305, the locking swing arm 306, the locking element bearing 307, the slider 308, the slider guide slot 401, the low-pressure slender rod clamp holder 401, the low-pressure slender rod clamp 302, the locking mechanism box 303, the locking element bearing 306, the locking swing arm bearing 307, the locking element bearing 307, the slider 308, the slider guide slot 401, the locking mechanism guide slot 401, the high-low-pressure control box, the high-pressure control box, the low pressure control box, the, The hydraulic power assisting device comprises a power assisting mechanism box body 402, a power assisting spring 403, a spring pull rod 404, a shifting fork 405, a shifting fork roller 406, a gear 407, a rack 501, a hand wheel 502, a screw rod 503, an oil storage tank 504, a manual pump 505, a hydraulic pipeline 506 and a hydraulic cylinder.

Detailed Description

The invention is described in detail below with reference to the drawings and specific examples.

Example 1

As shown in fig. 1, a high-low pressure pilot valve, including high-pressure control box, low-pressure control box and guide's casing, guide's casing includes high-pressure guide's casing and low-pressure guide's casing, the high-pressure control box passes through high-pressure guide's casing and connects on the pipeline, the low-pressure control box passes through low-pressure guide's casing and connects on the pipeline, be provided with high-pressure piston between high-pressure control box and the high-pressure guide's casing, the one end of high-pressure piston is equipped with high pressure and holds the unit of holding power, be provided with the low pressure piston between low-pressure control box and the low-pressure guide's casing, the one end of low pressure piston is equipped with low pressure and holds the unit of holding power, low pressure piston and high-pressure piston contact with traction lock pendulum rod respectively.

The high-pressure power storage unit is a high-pressure control spring which is fixed on the high-pressure control box body through an adjusting nut.

The low-pressure power storage unit is a low-pressure control spring which is fixed on the low-pressure control box body through an adjusting nut.

A cut-off valve is arranged between the pilot shell and the pipeline.

Under normal working conditions, the upward thrust of the medium pressure to the low-pressure piston is greater than or equal to the spring force of the low-pressure control spring, the upward thrust of the medium pressure to the high-pressure piston is less than or equal to the spring force of the high-pressure control spring, and the system is kept stable at the moment. When the medium pressure is higher than the set pressure, the upward thrust of the medium pressure to the high-pressure piston is larger than the spring force of the high-pressure control spring, so that the high-pressure piston is displaced.

The accurate control of the set pressure is achieved by selecting control springs of different models to be matched with the fine adjustment of the adjusting nut.

Example 2

As shown in fig. 2, a high-low pressure pilot valve, including high-pressure control box, low-pressure control box and guide's casing, guide's casing includes high-pressure guide's casing and low-pressure guide's casing, the high-pressure control box passes through high-pressure guide's casing and connects on the pipeline, the low-pressure control box passes through low-pressure guide's casing and connects on the pipeline, be provided with high-pressure piston between high-pressure control box and the high-pressure guide's casing, the one end of high-pressure piston is equipped with high pressure and holds the unit of holding power, be provided with the low pressure piston between low-pressure control box and the low-pressure guide's casing, the one end of low pressure piston is equipped with low pressure and holds the unit of holding power, low pressure piston and high-pressure piston contact with traction lock pendulum rod respectively.

The high-pressure power storage unit is a high-pressure slender rod, and the high-pressure slender rod is fixed with the high-pressure control box body through a high-pressure slender rod clamp.

The low-pressure power storage unit is a low-pressure control spring which is fixed on the low-pressure control box body through an adjusting nut.

A cut-off valve is arranged between the pilot shell and the pipeline.

Under normal working conditions, the upward thrust of the medium pressure to the low-pressure piston is greater than or equal to the spring force of the low-pressure control spring, the upward thrust of the medium pressure to the high-pressure piston is less than or equal to the rated load of the high-pressure slender rod, and the system is kept stable at the moment. When the medium pressure is higher than the set pressure, the upward thrust of the medium pressure to the high-pressure piston is larger than the rated load of the high-pressure slender rod, and the high-pressure slender rod bends to enable the high-pressure piston to displace.

The accurate control of the set pressure is achieved by selecting control springs of different models to match with the fine adjustment of the adjusting nut and selecting different models of the slender rod.

Example 3

As shown in fig. 3, a high-low pressure pilot valve, including high-pressure control box, low-pressure control box and guide's casing, guide's casing includes high-pressure guide's casing and low-pressure guide's casing, the high-pressure control box passes through high-pressure guide's casing and connects on the pipeline, the low-pressure control box passes through low-pressure guide's casing and connects on the pipeline, be provided with high-pressure piston between high-pressure control box and the high-pressure guide's casing, the one end of high-pressure piston is equipped with high pressure and holds the unit of holding power, be provided with the low pressure piston between low-pressure control box and the low-pressure guide's casing, the one end of low pressure piston is equipped with low pressure and holds the unit of holding power, low pressure piston and high-pressure piston contact with traction lock pendulum rod respectively.

The high-pressure power storage unit is a high-pressure slender rod, and the high-pressure slender rod is fixed with the high-pressure control box body through a high-pressure slender rod clamp.

The low-pressure power storage unit is a low-pressure control spring which is fixed on the low-pressure control box body through an adjusting nut.

A low-pressure slender rod cage is arranged below the low-pressure pilot shell, the low-pressure piston penetrates through the low-pressure pilot shell and extends into the low-pressure slender rod cage, a low-pressure slender rod is fastened at the other end of the low-pressure piston, and the low-pressure slender rod is fixed with the low-pressure slender rod cage through a low-pressure slender rod holder.

This is not a physical mechanism, as the rod instability is induced by high pressure, but not by low pressure. The control of the low pressure shut off function is controlled by the low pressure elongated stem and the low pressure control spring together. Under normal working conditions, the sum of the upward thrust of the medium pressure to the low-pressure piston and the rated load of the slender rod is greater than or equal to the spring force of the low-pressure control spring, and at the moment, the system is kept stable. When the medium pressure is lower than the set pressure, the sum of the upward thrust of the medium pressure on the low-pressure piston and the rated load of the slender rod is smaller than the spring force of the low-pressure control spring, and the spring force bends the slender rod and enables the low-pressure piston to displace under the thrust of the low-pressure control spring.

A cut-off valve is arranged between the pilot shell and the pipeline.

Example 4

As shown in fig. 4, a high-low pressure pilot valve, includes high-low pressure control box, high-low pressure control box is connected with the pipeline through guide's casing, be equipped with high-pressure piston and low pressure piston between high-low pressure control box and the guide's casing, high-pressure piston one end is equipped with high pressure control spring, low pressure piston one end is equipped with low pressure control spring, low pressure piston and high pressure piston contact with traction lock pendulum rod respectively.

The high-pressure piston is nested outside the low-pressure piston, and the high-pressure control spring is nested outside the low-pressure control spring; or the low-pressure piston is nested outside the high-pressure piston, and the low-pressure control spring is nested outside the high-pressure control spring.

A cut-off valve is arranged between the pilot shell and the pipeline.

The high-pressure control spring is fixed on the high-pressure control box body through an adjusting nut.

And the low-pressure control spring is fixed on the low-pressure control box body through an adjusting nut.

Under normal working conditions, the upward thrust of the medium pressure to the low-pressure piston is greater than or equal to the spring force of the low-pressure control spring, the upward thrust of the medium pressure to the high-pressure piston is less than or equal to the spring force of the high-pressure control spring, and the system is kept stable at the moment. When the medium pressure is higher than the set pressure, the upward thrust of the medium pressure to the high-pressure piston is larger than the spring force of the high-pressure control spring, so that the high-pressure piston is displaced.

The accurate control of the set pressure is achieved by selecting control springs of different models to be matched with the fine adjustment of the adjusting nut.

Example 5

As shown in fig. 5 to 7, a high-low pressure emergency cut-off device for a pipeline includes a high-low pressure pilot valve and a main valve according to one of embodiments 1 to 4, wherein two sides of the main valve are respectively connected to an upstream pipeline and a downstream pipeline, the high-low pressure pilot valve is connected to the downstream pipeline, a traction lock swing rod in the high-low pressure pilot valve is connected to a locking mechanism through a traction lock, the locking mechanism is connected to a power-assisted mechanism, and the power-assisted mechanism is connected to the main valve.

As shown in fig. 8, the locking mechanism includes a locking mechanism box, two locking swing arms and a locking element, one ends of the two locking swing arms are locked with the spring pull rod of the power-assisted mechanism, the other ends of the two locking swing arms are in contact with the locking element through locking swing arm bearings, and the locking element is connected with the traction lock.

As shown in fig. 9, the power assisting mechanism is an angular travel power assisting mechanism, the angular travel power assisting mechanism includes a power assisting mechanism box, a spring pull rod is arranged in the power assisting mechanism box, a power assisting spring is sleeved on the spring pull rod, a shifting fork roller is installed on the spring pull rod, a shifting fork is arranged on the shifting fork roller, the shifting fork is connected to a main valve (an angular travel switch valve, such as a ball valve and a butterfly valve), and the locking swing arm is used for maintaining the deformation state of the spring.

As shown in fig. 10, the power assisting mechanism is provided with a reset mechanism, the reset mechanism comprises a hand wheel and a screw rod, and the screw rod is connected with the spring pull rod.

Example 6

In contrast to example 5: as shown in fig. 11, assist drive includes assist drive box, the assist drive box is internal to be equipped with the spring pull rod, the cover has helping hand spring on the spring pull rod, install the rack on the spring pull rod, the rack cooperatees with the gear, gear connection is on the main valve, the locking swing arm is used for maintaining the deformation state of spring.

Example 7

In contrast to example 5: as shown in fig. 12, the locking mechanism includes a locking mechanism box and a locking element, one end of the locking element is axially fixed in the locking mechanism box, the other end of the locking element is provided with a locking element bearing, the locking element bearing contacts with one end of the slide block guide groove, the other end of the slide block guide groove is axially fixed in the locking mechanism box, a slide block is arranged in the slide block guide groove, the slide block is installed at the tail end of a spring pull rod of the power assisting mechanism, and the locking element is connected with the traction lock.

As shown in fig. 13-14, the power-assisted mechanism is a linear stroke power-assisted mechanism, and comprises a power-assisted mechanism box body, a spring pull rod is arranged in the power-assisted mechanism box body, a power-assisted spring is sleeved on the spring pull rod, the spring is compressed between the power-assisted mechanism box body and the spring pull rod, and the spring pull rod is connected with a main valve (a linear stroke switch valve, such as a gate valve).

Example 8

In contrast to example 5: as shown in fig. 15, be equipped with canceling release mechanical system on the assist drive device, canceling release mechanical system includes batch oil tank, hand pump, hydraulic pressure pipeline, install the hand pump on the hydraulic pressure pipeline, the one end of hydraulic pressure pipeline is located the batch oil tank, the first section of hydraulic pressure pipeline is connected with the pneumatic cylinder, the assist drive device box constitutes the pneumatic cylinder with spring pull rod top.