CN110725978A - Quick automatic shut-off device and natural gas wellhead emergency cut-off device - Google Patents

Abstract

The invention relates to a device that can quickly and automatically close a valve when a trigger condition occurs, and belongs to the technical field of safety protection. The invention utilizes technical means such as overpressure control pilot valve, underpressure control pilot valve, and oil circuit design, and utilizes piston movement to effectively avoid the replacement process of the blasting needle, which not only saves the cost of consumables, but also saves time. In addition, in the present invention, the force of the medium pressure on the overpressure control pilot valve and the underpressure control pilot valve is directly used to realize overpressure triggering and underpressure triggering, which not only does not require other converters, but is more direct and sensitive, and has a faster response speed. quick. At the same time, the present invention can use a spring preload regulator at the springs of the overpressure control pilot valve and the underpressure control pilot valve, thereby making the threshold value control of overpressure and underpressure more convenient and accurate.

Description

Quick automatic shut-off device and natural gas wellhead emergency cut-off device

technical field

The invention relates to a device that can quickly and automatically close a valve under triggering conditions, in particular to a device that can quickly and automatically closes and a natural gas wellhead emergency cut-off device, which belongs to the technical field of safety assurance.

Background technique

Due to the change of pressure during the transportation of gas or liquid, there may be a safety hazard in the entire transportation process. Therefore, in general, devices are installed on the pipeline to control the flow of gas or liquid, so as to avoid safety accidents caused by pressure changes in the pipeline. A common method is to provide an actuator for these devices, so that the device can be closed quickly and sensitively.

For example, in the construction of natural gas acquisition projects, such pressure-sensitive devices are usually installed, which can quickly and emergency cut off when the pressure exceeds the set range. When the wellhead medium pressure exceeds the preset high pressure limit, the device can be quickly and automatically shut down to prevent downstream equipment from being damaged due to pressure overload; at the same time, when the wellhead medium pressure is lower than the preset low pressure limit, the device can also be quickly and automatically shut down , the placement system equipment is destroyed.

The inventor of the present invention discloses a natural gas wellhead emergency cut-off device in CN207246497U. In this patent, the blasting needle is used as the trigger element, which can cut off the gas passage of the natural gas wellhead with high precision and fast.

However, during use, we found that this device still has some shortcomings. For example, the blasting needle used as the trigger element is damaged during the triggering process, which makes it impossible to use it repeatedly. After the device is triggered, it must be The reset can only be done by replacing the blasting needle, which not only increases the cost of consumables, but also increases the time cost of reset. At the same time, since the gas-liquid conversion system needs to be used in the design, the overall structure is relatively complicated, and the cost is relatively high.

Therefore, how to solve these problems actually generated in the application, and to propose a more optimized design and solution, is the direction that the inventor has been working hard to research.

SUMMARY OF THE INVENTION

The purpose of the invention is to find a new technical solution, which can optimize the reset link and reduce the cost of consumables and time for reset after triggering.

In order to achieve this purpose of the invention, the present invention discloses a device that can be quickly and automatically closed for emergency shut-off of natural gas wellheads. The device includes an on-off valve and a single-acting actuator for controlling the on-off valve, wherein the single-acting actuator is hydraulic The oil-controlled single-acting actuator also includes an oil storage tank, the piston cavity of the single-acting actuator and the oil storage tank are communicated through the actuator oil filling pipeline, and also includes an overpressure control pilot valve and an underpressure control pilot valve, Both sides of the side wall of the overpressure control pilot valve are correspondingly provided with an overpressure oil injection hole and an overpressure oil outlet hole, and the piston rod of the overpressure control pilot valve is provided with two annular grooves, which are respectively the overpressure passage grooves. and overpressure closed-circuit groove, the overpressure oil injection hole (or overpressure oil outlet hole) is always located at the overpressure passage groove, and the overpressure oil outlet hole (rear overpressure oil injection hole) is located at the spring static state. The overpressure closed-circuit groove is located at the overpressure passage groove when the spring is compressed; the underpressure control pilot valve is provided with underpressure oil injection holes and underpressure oil outlet holes correspondingly on both sides of the side wall of the underpressure control pilot valve. There are two annular grooves on the piston rod of the pilot valve, which are the underpressure passage groove and the underpressure closed circuit groove respectively. The underpressure oil outlet (or underpressure oil injection hole) is always located at the underpressure passage groove , the under-pressure oil injection hole (or under-pressure oil outlet hole) is located at the under-pressure closed-circuit groove when the spring is compressed, and is located at the under-pressure channel groove when the spring returns to a static state; the over-pressure oil injection hole and The oil storage tanks are connected through the oil filling pipeline of the overpressure control pilot valve, the underpressure oil filling hole and the oil storage tank are connected through the oil filling pipeline of the underpressure control pilot valve, and the overpressure oil outlet hole and the oil storage tank are connected by the oil filling pipeline. The overpressure oil return pipeline is connected, the underpressure oil outlet hole and the oil storage tank are connected through the underpressure oil return pipeline, the overpressure control pilot valve oil injection pipeline and the underpressure control pilot valve oil injection pipeline are connected in parallel, And after they are connected in parallel, they are connected in parallel with the oil filling pipeline of the execution structure to form a main oil filling pipeline, and the overpressure oil return pipeline is connected in parallel with the underpressure oil return pipeline.

Further preferably, the overpressure control pilot valve and the underpressure control pilot valve are respectively provided with a spring preload regulator, the spring preload regulator includes a spring connection block, and the spring connection block is provided with a bolt hole. , and also includes a spring preload adjustment bolt, the spring preload adjustment bolt is installed in the bolt hole, the spring connection block is located in the piston housing, and the spring preload adjustment bolt is exposed outside the piston housing.

Further preferably, a pressure relief bypass is also provided on the main oil supply pipeline, and the pressure relief bypass is formed by a pressure relief pipe connected to the oil storage tank at one end and connected to the main oil supply pipeline at the other end. A pressure relief valve is provided.

In a preferred technical solution, the single-acting actuator is a fork-type single-acting actuator.

In addition, in a preferred technical solution, a manual pressure test pump is also included, and the manual pressure test pump includes a pressure test oil barrel and a pressure test handle, and the pressure test oil barrel is connected with the pressure test handle through a connecting rod, so One end of the pressure test handle is fixed, and the other end rotates with the fixed point as the axis, and a check valve is also arranged at the outlet of the manual pressure test pump.

An oil storage tank is a natural gas wellhead emergency shut-off device equipped with the aforementioned device that can be quickly and automatically closed. The on-off valve is installed on a natural gas pipeline, the upstream pipeline is located upstream of the on-off valve, and the downstream pipeline is located downstream of the on-off valve. The upstream pipeline It communicates with the overpressure control pilot valve and the underpressure control pilot valve through the first sampling line and the second sampling line, respectively.

In a preferred technical solution, a first manual cut-off valve and a second manual cut-off valve are respectively provided on the first sampling line and the second sampling line.

It is necessary to explain the several structures mentioned above. First of all, it is a single-acting actuator. The single-acting actuator is generally pneumatic, that is, driven by an air source, but in the present invention, it is hydraulic. Oil controlled single acting actuator. The position where the hydraulic oil acts is the piston cavity of the single-acting actuator.

Specifically, a fork-type single-acting actuator is preferably used in the present invention, including a piston rod, a fork mechanism, a spring and an outer casing. One end of the fork mechanism is fixed by a shaft, and the shaft is fixed in the outer casing. The other end of the fork mechanism is fixed on the piston rod, one end of the piston rod is fixed with the inner side of the outer casing by a spring, and the other end of the piston rod cooperates with the casing to form a piston cavity. In the static state, the piston cavity is filled with oil, so pressure is generated on the spring to make it in a compressed state, and the fork mechanism is in the first position (that is, the opening and closing position of the switch valve). When it is opened, the oil in the piston cavity returns to the oil cylinder, the pressure on the spring disappears, the spring returns to the non-compressed state due to its own restoring force, and the fork mechanism rotates to the second position (that is, the on-off valve closed position).

Another structure that needs to be explained is the overpressure control pilot valve and the underpressure control pilot valve. The pilot valve is composed of a piston rod and a piston sleeve that is airtightly matched with the piston rod. One end of the piston rod is fixed to the piston sleeve by a spring. On the inner wall, the other end of the piston rod cooperates with the piston sleeve to form a piston cavity, and the sliding of the piston rod in the piston sleeve can be realized by the change in magnitude between the pressure in the piston cavity and the rebound force of the spring. When two through holes at different levels are opened on the side wall of the piston sleeve, the opening and closing of the piston passage can be realized by combining the movement of the piston rod with the annular groove formed on the pilot valve. Specifically explained here, when the through holes at different levels are in an annular groove at the same time, the passage is opened; when the through holes at different levels are not in an annular groove at the same time, the passage is closed at this time.

After the technical solution disclosed in the present invention is adopted, since the overpressure control pilot valve or the underpressure control pilot valve is the piston movement during the triggering process, when the system pressure returns to normal, it can be automatically reset to the static original position due to the action of the spring , thereby avoiding the replacement process of the blasting needle, saving not only the cost of consumables but also the cost of time. In addition, in the present invention, the force of the medium pressure on the overpressure control pilot valve and the underpressure control pilot valve is directly used to realize overpressure triggering and underpressure triggering, which not only does not require other converters, but is more direct, sensitive, and has a faster response speed. faster. In addition, since the present invention can utilize spring preload regulators at the springs of the overpressure control pilot valve and the underpressure control pilot valve, the threshold value control of overpressure and underpressure can be more convenient and accurate.

Description of drawings

FIG. 1 is a schematic diagram of the static state of the device that can be quickly and automatically shut down installed at the natural gas wellhead.

Figure 2 is an enlarged view of the overpressure control pilot valve and the underpressure control pilot valve.

Figure 3 is a schematic diagram of the overpressure state of the device that can be quickly and automatically shut down installed at the natural gas wellhead.

FIG. 4 is a schematic diagram of the underpressure state of the device that can be quickly and automatically shut down installed at the natural gas wellhead.

Detailed ways

For a better understanding of the present invention, the present invention will be further described below with reference to specific embodiments.

As shown in Fig. 1, a device that can be quickly and automatically closed for emergency cut-off of natural gas wellheads includes an on-off valve 1 and a single-acting actuator 2 for controlling the on-off valve. The single-acting actuator is a hydraulic oil-controlled single-acting actuator. The acting actuator also includes an oil storage tank 3, the piston cavity 201 of the single-acting actuator and the oil storage tank 3 are communicated with the oil filling pipeline 4 of the execution structure, and also includes an overpressure control pilot valve 5 and an underpressure control pilot valve 6. Looking at Fig. 2, both sides of the side wall of the overpressure control pilot valve 5 are correspondingly provided with an overpressure oil injection hole 501 and an overpressure oil outlet hole 502, and the piston rod of the overpressure control pilot valve is provided with two There are two annular grooves, which are respectively the overpressure passage groove 503 and the overpressure closed circuit groove 504. The overpressure oil injection hole 501 is always located at the overpressure passage groove 503, and the overpressure oil outlet hole 502 is in the static state of the spring. The bottom is located at the overpressure closed-circuit groove 504 (in the state of Fig. 2), and is located at the overpressure passage groove 503 when the spring is compressed. With reference to Fig. 2, when the piston rod is pushed and moved upward, the spring is compressed. At this time The overpressure passage groove 503 located below is communicated with the overpressure oil outlet hole 502, so that the overpressure oil injection hole 501 and the overpressure oil outlet hole 502 are all communicated with the overpressure passage groove 503, thereby forming an oil passageway; In Fig. 2, the underpressure control pilot valve 6 is provided with underpressure oil filling 601 and underpressure oil outlet 602 correspondingly on both sides of the side wall of the underpressure control pilot valve 6. The piston rod of the underpressure control pilot valve is provided with two annular grooves, respectively For the under-pressure passage groove 603 and the under-pressure closed-circuit groove 604, the under-pressure oil outlet hole 602 is always located at the under-pressure passage groove 603, and the under-pressure oil injection hole 604 is in the state of being compressed by the spring (shown in FIG. 2 ). In the state shown) at the underpressure closed-circuit groove 604, and at the underpressure passage groove 603 when the spring returns to rest state, with reference to Figure 2, when the piston rod moves downward under the action of the spring's resilience, the elastic potential energy of the spring At this time, the underpressure passage groove 603 located at the top moves downward and communicates with the oil injection hole 601, so that the underpressure oil injection hole 601 and the underpressure oil outlet hole 602 are connected with the underpressure passage groove 603 to form oil. 1 below, the overpressure oil filling hole 501 and the oil storage tank 3 are connected through the overpressure control pilot valve oil filling pipeline 7, and the underpressure oil filling hole 601 and the oil storage tank 3 are controlled by the underpressure control The pilot valve oil filling line 8 is connected, the overpressure oil outlet hole 502 and the oil storage tank 3 are connected through the overpressure oil return line 9, and the underpressure oil outlet hole 602 and the oil storage tank 3 are connected through the underpressure oil return pipe The oil filling line 7 of the overpressure control pilot valve and the oil filling line 8 of the underpressure control pilot valve are connected in parallel, and after they are connected in parallel, they are connected in parallel with the oil filling line 4 of the actuator to form the main oil filling line 11. The overpressure oil return pipeline 9 is connected in parallel with the underpressure oil return pipeline 10 .

In this embodiment, it is further preferred that the overpressure control pilot valve and the underpressure control pilot valve are respectively provided with spring preload regulators, the spring preload regulators include a spring connection block 12 , and the spring connection block There is a bolt hole on the upper part, and also includes a spring preload adjustment bolt 13, the spring preload adjustment bolt is installed in the bolt hole, the spring connection block is located in the piston housing, and the spring preload adjustment bolt is exposed on the piston housing. in vitro.

At the same time, as shown in FIG. 1 , the main oil supply pipeline 11 is also provided with a pressure relief bypass 14 , the pressure relief bypass is connected to the oil storage tank 3 at one end, and the other end is connected to the pressure relief pipe of the main oil supply pipeline The pressure relief pipe is also provided with a pressure relief valve 15.

As shown in FIGS. 1-4 , the single-acting actuator is a fork-type single-acting actuator. Referring to Fig. 1 in particular, we can see that the fork-type single-acting actuator includes a piston rod 201, a fork mechanism 202, a spring 203 and an outer casing 204, and one end of the fork mechanism is fixed by a shaft, as shown in Fig. 1 At point A, the shaft is fixed in the outer casing, and the other end of the fork mechanism is fixed on the piston rod, as shown in point B in Figure 1, one end of the piston rod is fixed to the inner side of the outer casing through a spring, and the other end of the piston rod is fixed to the casing The fit forms the piston cavity 205 . In the static state, the piston cavity is filled with oil, so pressure is generated on the spring to make it in a compressed state, and the fork mechanism is in the first position (that is, the opening and closing position of the switch valve). When it is opened, the oil in the piston cavity returns to the oil cylinder, the pressure on the spring disappears, the spring returns to the non-compressed state due to its own restoring force, and the fork mechanism rotates to the second position (that is, the on-off valve closed position).

In this embodiment, we further disclose a preferred technical solution, which further includes a manual pressure test pump. The manual pressure test pump includes a pressure test oil barrel 1701 and a pressure test handle 1702. The pressure test oil barrel passes through the The connecting rod 1703 is connected with the pressure test handle, one end of the pressure test handle is fixed, and the other end rotates with the fixed point as the axis. The outlet of the manual pressure test pump is also provided with a one-way valve 16 .

In this embodiment, we further disclose a natural gas wellhead emergency shut-off device equipped with the aforementioned device that can be quickly and automatically closed. As shown in Figures 1 to 4, the switch valve 1 is installed on the natural gas pipeline, located at the switch The upstream pipeline 18 is upstream of the valve, and the downstream pipeline 19 is located downstream of the on-off valve. The upstream pipelines communicate with the overpressure control pilot valve 5 and the underpressure control pilot valve 6 through the first sampling line 20 and the second sampling line 21, respectively. .

It is further preferred that in a preferred technical solution, the first sampling line 20 and the second sampling line 21 are further provided with a first manual cut-off valve 22 and a second manual cut-off valve 23, respectively.

Below, we will explain how the device disclosed in the present invention quickly realizes the cut-off of the on-off valve in the state of overpressure and underpressure with reference to Fig. 1 , Fig. 3 and Fig. 4 .

First, what is shown in Figure 1 is the position of each component of the device under normal system pressure. We see that in this state, both the overpressure control pilot valve and the underpressure control pilot valve are in a closed state, that is, a cut-off state, and the spring in the single-acting actuator is compressed due to the action of hydraulic oil. In the energy storage state, the on-off valve is in the open state, and the natural gas flows into the downstream pipeline through the upstream pipeline through the on-off valve, and the whole system operates normally.

Then we refer to Figure 3 to illustrate how to achieve a quick shut-off in overpressure conditions. As shown in Figure 3, when the pressure in the upstream line is higher than the set high pressure threshold, the pressure pushes the piston in the overpressure control pilot valve to move upward. The overpressure passage groove located below is connected with the overpressure oil outlet hole, so that the overpressure oil injection hole and the overpressure oil outlet hole are connected with the overpressure passage groove, so that the oil passageway is conducted, and the piston cavity of the single-acting actuator is connected. The hydraulic oil inside flows back to the oil cylinder through the oil passage. At the same time, because the hydraulic oil in the piston cavity flows back to the oil storage tank through the passage, its force on the spring disappears, and the spring is compressed from the compression force under the action of the restoring force. When the state is released, the piston rod moves to the right, and makes the fork mechanism rotate 90°, so that the switch valve is switched to the closed state, and the purpose of fast cutting is realized.

Then we refer to Figure 4 to illustrate how to achieve a quick cut off in the underpressure condition. As shown in Figure 4, when the pressure in the upstream line is lower than the set low pressure threshold, the balance between this pressure and the spring in the underpressure control piston is broken, and the spring pushes the piston downward under the action of the restoring force , as shown before, in this state, the underpressure passage groove located above moves down and communicates with the oil injection hole, so that the underpressure oil injection hole and the underpressure oil outlet hole are connected with the underpressure passage groove, so that the oil The hydraulic oil in the piston cavity of the single-acting actuator circulates and returns to the oil storage tank through the oil passage. When the force disappears, the spring is released from the compressed state under the action of the restoring force, the piston rod moves to the right, and the fork mechanism rotates 90°, so that the on-off valve is switched to the closed state to achieve the purpose of fast cutting.

When the pressure returns to the normal range, only the hydraulic oil in the oil storage tank needs to be re-injected into the piston cavity of the single-acting actuator through the manual pressure test pump, and the whole device can be returned to the state shown in Figure 1.

The whole process is not only fast, but also easy to restore, without the need to replace accessories.

The above are specific embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims (7)

1. Device that can fast self-closing, its characterized in that: the device comprises a switch valve, a single-action executing mechanism for controlling the switch valve, an oil storage tank and a hydraulic oil control system, the piston cavity of the single-action actuating mechanism is communicated with the oil storage tank through an actuating mechanism oil injection pipeline, and the single-action actuating mechanism also comprises an overpressure control pilot valve and a pressure loss control pilot valve, an overpressure oil injection hole and an overpressure oil outlet hole are correspondingly arranged at two sides of the side wall of the overpressure control pilot valve, two annular grooves are arranged on a piston rod of the overpressure control pilot valve and respectively are an overpressure passage groove and an overpressure closed-circuit groove, the overpressure oil hole (or overpressure oil outlet hole) is always positioned at the overpressure passage groove, the overpressure oil outlet hole (rear overpressure oil inlet hole) is positioned at the overpressure closed-circuit groove in the static state of the spring, and the overpressure passage groove is positioned in the compressed state of the spring; the two sides of the side wall of the pressure-deficient control pilot valve are correspondingly provided with a pressure-deficient oil injection hole and a pressure-deficient oil outlet, a piston rod of the pressure-deficient control pilot valve is provided with two annular grooves which are a pressure-deficient passage groove and a pressure-deficient closed-circuit groove respectively, the pressure-deficient oil outlet (or pressure-deficient oil injection hole) is always positioned at the pressure-deficient passage groove, the pressure-deficient oil injection hole (or pressure-deficient oil outlet) is positioned at the pressure-deficient closed-circuit groove under the state that a spring is compressed, and is positioned at the pressure-deficient passage groove under the state that the spring returns to a static state; the oil injection device is characterized in that the overpressure oil injection hole is communicated with the oil storage tank through an overpressure control pilot valve oil injection pipeline, the pressure loss oil injection hole is communicated with the oil storage tank through a pressure loss control pilot valve oil injection pipeline, the overpressure oil outlet hole is communicated with the oil storage tank through an overpressure oil return pipeline, the pressure loss oil injection hole is communicated with the oil storage tank through a pressure loss oil return pipeline, the overpressure control pilot valve oil injection pipeline is connected with the pressure loss control pilot valve oil injection pipeline in parallel, and after the overpressure control pilot valve oil injection pipeline is connected in parallel, the overpressure control pilot valve oil injection pipeline is connected with the actuator oil injection pipeline in parallel to form a main oil injection pipeline, and the overpressure oil return pipeline is connected with the pressure loss oil return pipeline.

2. The device capable of being automatically and rapidly closed according to claim 1, wherein: the overpressure control pilot valve and the pressure loss control pilot valve are respectively provided with a spring pre-tightening regulator, the spring pre-tightening regulator comprises a spring connecting block, a bolt hole is formed in the spring connecting block, the spring pre-tightening regulating device further comprises a spring pre-tightening regulating bolt, the spring pre-tightening regulating bolt is arranged in the bolt hole, the spring connecting block is located in the piston shell, and the spring pre-tightening regulating bolt is exposed outside the piston shell.

3. The device capable of being automatically and rapidly closed according to claim 1, wherein: the oil supply main pipeline is further provided with a pressure relief bypass, the pressure relief bypass is formed by connecting one end of the pressure relief bypass with the oil storage tank and communicating the other end of the pressure relief bypass to the pressure relief pipe of the oil supply main pipeline, and the pressure relief pipe is further provided with a pressure relief valve.

4. A device capable of being automatically and rapidly closed according to any one of claims 1 to 3, wherein: the single-action actuating mechanism is a shifting fork type single-action actuating mechanism.

5. A device capable of being automatically and rapidly closed according to any one of claims 1 to 3, wherein: still including manual pressure testing pump, manual pressure testing pump includes pressure testing oil drum, pressure testing handle, the pressure testing oil drum passes through the connecting rod and is connected with the pressure testing handle, pressure testing handle one end is fixed, and the other end uses this fixed point to rotate as the axle center, manual pressure testing pump's exit still is provided with the check valve.

6. A natural gas wellhead emergency shut-off device equipped with the device capable of rapid automatic closing according to any one of claims 1 to 5, characterized in that: the switching valve device is arranged on the natural gas pipeline, an upstream pipeline is positioned on the upstream of the switching valve, a downstream pipeline is positioned on the downstream of the switching valve, and the upstream pipeline is respectively communicated with the overpressure control pilot valve and the pressure-loss control pilot valve through a first sampling pipeline and a second sampling pipeline.

7. A natural gas wellhead emergency shut-off device having a device for rapid automatic shut-off according to claim 6, wherein: and the first sampling pipeline and the second sampling pipeline are respectively provided with a first manual cut-off valve and a second manual cut-off valve.

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