A kelly cock valve remote control system with a check valve

Abstract

The present application relates to the technical field of oil and gas drilling control, and discloses a kelly cock valve remote control system with a check valve, which comprises a kelly cock valve body, a pneumatic actuator, a solenoid valve, a PLC controller, a computer terminal and a check valve; the kelly cock valve body is coaxial (integral or separate) with the downstream check valve and is connected in series; the output shaft of the pneumatic actuator is in transmission connection with the valve stem of the kelly cock valve body, and the solenoid valve is in communication with the gas inlet of the pneumatic actuator; the PLC controller is connected with the control coil inside the solenoid valve and the computer terminal; when the downhole fluid upwells reversely, the check valve preferentially closes to block the high-pressure fluid, thereby reducing the working pressure difference in the kelly cock valve body and the closing torque; the operator issues an instruction through the computer terminal, the solenoid valve is triggered to switch the gas circuit through the PLC controller, and the pneumatic actuator is driven to complete the remote closing of the kelly cock valve. The closing resistance of the valve under pressure is reduced, the size of the driving device is reduced, and safe remote well control operation is realized.

Description

Technical Field

[0001] This invention relates to the field of oil and gas drilling control technology, specifically to a remote control system for a square drill pipe plug valve with a one-way valve. Background Technology

[0002] In oil and gas drilling operations, the quay pipe plug valve is a key well control tool installed on the drill string to prevent backflow of fluids in the well and control blowouts. During normal drilling, the plug valve remains open to establish a circulation channel for drilling fluid; in emergency situations such as well kicks or reverse flow of formation fluids, the plug valve needs to be quickly closed to cut off the fluid passage inside the tubing string.

[0003] Current angular drill pipe plug valves have certain limitations in practical applications. When high-pressure fluid flows upwards from the well and acts directly on the plug valve, a high working pressure difference is formed between the upper and lower ends of the valve core. This pressure difference causes the valve core to press tightly against the side sealing seat, resulting in a significant increase in the mechanical friction resistance when the valve core rotates to close. The driving torque required to close the valve also increases accordingly, and in severe cases, it can cause the valve to jam. To overcome this high shut-off torque, a large power actuator is usually required for the plug valve, which takes up too much of the limited working space at the wellhead on the drilling rig. In emergency situations, relying solely on operators to manually close the valve using auxiliary tools near the wellhead not only results in low overall shut-off efficiency but also seriously threatens the personal safety of on-site personnel in the event of a blowout. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a remote control system for a square drill pipe plug valve with a one-way valve. This system solves the problems of existing square drill pipe plug valves, such as increased closing torque due to excessive internal pressure difference when dealing with high-pressure backflushing fluids downhole, easy mechanical jamming, and safety hazards posed by manual shut-off.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a remote control system for a square drill pipe plug valve with a check valve, comprising a square drill pipe plug valve body, a pneumatic actuator, a solenoid valve, a PLC controller, a computer terminal, and a check valve; The square drill pipe plug valve body and the check valve are coaxially (integrated or separate) connected in series to form a downhole fluid channel. The check valve is located downstream of the fluid discharge side of the square drill pipe plug valve body. The pneumatic actuator is installed on the outer housing of the square drill pipe plug valve body, and the output shaft of the pneumatic actuator is connected to the valve stem of the square drill pipe plug valve body. The solenoid valve is installed on the outside of the pneumatic actuator, and the air source output end of the solenoid valve is connected to the air inlet of the pneumatic actuator; The PLC controller's network communication interface is connected to the computer to establish a wired communication link, and the PLC controller's signal output terminal is connected to the control coil inside the solenoid valve.

[0006] As a further improvement of the present invention, a filter pressure reducing valve is also included, wherein the outlet of the filter pressure reducing valve is connected to the air source input pipeline of the solenoid valve.

[0007] As a further improvement of the present invention, the one-way valve includes a one-way valve body, a one-way valve core, a spring, and a spring seat; the one-way valve body has a through-hole forming a valve cavity that connects the upstream and downstream, and the inner wall of the valve cavity is provided with a break at the section contraction near the fluid inlet; the one-way valve core is coaxially disposed inside the valve cavity, and a circular through hole is opened on the one-way valve core; the two ends of the spring abut against the one-way valve core and the spring seat respectively.

[0008] As a further improvement of the present invention, when the one-way valve core is set away from the shut-off port, there is a flow gap between the end face of the one-way valve core and the shut-off port, and the circular through hole is not blocked by the inner wall of the one-way valve body.

[0009] As a further improvement of the present invention, when the one-way valve core is positioned close to the shut-off port, the end face of the one-way valve core and the shut-off port form a surface fit, and the circular through hole is blocked by the inner wall of the one-way valve body.

[0010] As a further improvement of the present invention, the outer side of the spring seat is machined with an external thread, and the inner wall of the tail of the one-way valve body is machined with a matching internal thread. The spring seat is connected to the tail of the one-way valve body by the engagement of the external thread and the internal thread.

[0011] As a further improvement of the present invention, the pneumatic actuator housing is provided with an air inlet A and an air inlet B on both sides respectively; the pneumatic actuator is provided with a piston and a gear; the side of the piston is machined with a rack structure, which physically meshes with the gear; the center hole of the gear is rigidly connected to the output shaft.

[0012] As a further improvement of the present invention, a limit screw is fitted at the end of the housing of the pneumatic actuator, and the end of the limit screw extends into the cylinder of the pneumatic actuator and forms mechanical interference with the end face of the piston.

[0013] As a further improvement of the present invention, the angular drill pipe plug valve body includes a valve body, a valve stem, a valve core, and a connecting thread; the valve core is disposed inside the valve body, and one end of the valve stem is connected to the valve core; the connecting thread at the end of the one-way valve is fixedly connected to the connecting thread at the bottom of the angular drill pipe plug valve body.

[0014] As a further improvement of the present invention, the solenoid valve is provided with a moving iron core component with a piston inside, and the moving iron core component with the piston is located within the working magnetic field range of the control coil.

[0015] This invention provides a remote control system for a square drill pipe plug valve with a one-way valve. It has the following advantages: 1. This invention connects a one-way valve coaxially (integrated or separate) downstream of the angular drill pipe plug valve body. Utilizing the cooperative structure of the one-way valve core and spring, it automatically resets when encountering reverse upward flow of downhole fluid to preferentially block high-pressure fluid. This reduces the fluid pressure differential inside the angular drill pipe plug valve body, decreases the mechanical drive torque required to rotate the valve core, reduces the frictional resistance and sealing surface wear when the valve core rotates and closes, and prevents the valve from jamming under pressure.

[0016] 2. This invention uses a pneumatic actuator to drive the valve stem of the angular drill pipe plug valve through an internal gear and rack structure. Because the downstream front-mounted check valve reduces the closing torque requirement of the plug valve, the system can select a pneumatic actuator with a smaller cylinder volume and conventional thrust parameters. This effectively reduces the overall external size and weight of the control equipment, making it easier to install and arrange in environments with limited space at the wellhead of the drilling platform.

[0017] 3. This invention constructs a system that combines wired communication link with pneumatic control by configuring a PLC controller, solenoid valve, and computer terminal. In the event of an emergency blowout prevention situation, the operator can directly issue commands from the computer terminal far away from the danger zone. The PLC controller triggers the solenoid valve to complete the air circuit switching, and then uses air pressure to automatically close the plug valve. This changes the traditional operation mode that requires manual operation close to the wellhead to manually turn the valve, eliminating the safety hazards of close-range operation. Attached Figure Description

[0018] Figure 1 This is a system architecture diagram of the present invention; Figure 2 This is a flowchart of the method of the present invention; Figure 3 This is a schematic diagram showing the connection between the pneumatic actuator and the square drill pipe plug valve of the present invention; Figure 4 This is a structural diagram of the one-way valve assembly of the present invention; Figure 5 This is a cross-sectional view of the normal operating structure of the one-way valve assembly of the present invention; Figure 6 This is a cross-sectional view of the reverse shut-off structure of the one-way valve assembly of the present invention.

[0019] The components are as follows: 1. Square drill pipe plug valve body; 2. Pneumatic actuator; 3. Solenoid valve; 4. PLC controller; 5. Filter pressure reducing valve; 6. Computer terminal; 7. Check valve; 11. Valve body; 12. Valve stem; 13. Valve core; 14. Connecting thread; 21. Output shaft; 22. Air inlet A; 23. Air inlet B; 24. Limit screw; 25. Piston; 71. Check valve body; 72. Check valve core; 73. Spring; 74. Spring seat. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] See attached document Figure 1 , attached Figure 1 This is a schematic diagram of the overall structure of a remote control system for a square drill pipe plug valve with a check valve according to an embodiment of the present invention; see attached diagram. Figure 3 , attached Figure 3 This is a schematic diagram showing the connection between a pneumatic actuator and a angular drill pipe plug valve according to an embodiment of the present invention. The present invention provides a remote control system for an angular drill pipe plug valve with a check valve, comprising: an angular drill pipe plug valve body 1, a pneumatic actuator 2, a solenoid valve 3, a PLC controller 4, a filter pressure reducing valve 5, a computer terminal 6, and a check valve 7.

[0022] In this embodiment, the angular drill pipe plug valve body 1 and the check valve 7 are coaxially (integrated or separate) connected in series to form a downhole fluid channel. The check valve 7 is located downstream of the fluid discharge side of the angular drill pipe plug valve body 1. The pneumatic actuator 2 is mounted on the outer housing of the angular drill pipe plug valve body 1 via a mechanical flange and bolt fasteners. The solenoid valve 3 is fixedly mounted on the outside of the pneumatic actuator 2. The filter pressure reducing valve 5 is used to connect the external air source and the solenoid valve 3. The communication terminal of the PLC controller 4 is connected to the computer terminal 6, and the control terminal is connected to the solenoid valve 3.

[0023] In terms of mechanical assembly and connection, the connecting thread 14 at the end of the one-way valve 7 is fixedly connected to the connecting thread 14 at the bottom of the square drill pipe plug valve body 1. The output shaft 21 of the pneumatic actuator 2 is drivenly connected to the valve stem 12 of the square drill pipe plug valve body 1, and is used to transmit the driving torque to the internal valve core 13.

[0024] Regarding the air circuit connection and distribution, an external compressed air source pipeline is connected to the inlet of the filter and pressure reducing valve 5. The outlet of the filter and pressure reducing valve 5 is connected to the air source input pipeline of the solenoid valve 3. The air source output of the solenoid valve 3 is connected to the air inlet of the pneumatic actuator 2, forming the drive air circuit system.

[0025] In terms of electrical signal connection networking, the signal output terminal of PLC controller 4 is connected to the control coil inside solenoid valve 3 via a cable. The network communication interface of PLC controller 4 establishes a wired communication link with computer terminal 6 via a network cable.

[0026] See attached document Figure 2 , attached Figure 2This is a flowchart illustrating the steps of a remote control method for a square drill pipe plug valve with a one-way valve according to an embodiment of the present invention; see attached... Figure 4 , attached Figure 4 This is a structural diagram of a one-way valve assembly according to an embodiment of the present invention; see attached diagram. Figure 5 , attached Figure 5 This is a cross-sectional view of the normal operating structure of a one-way valve assembly according to an embodiment of the present invention; see attached... Figure 6 , attached Figure 6 This is a cross-sectional view of the reverse shut-off structure of a one-way valve assembly according to an embodiment of the present invention. The present invention provides a remote control method for a square drill pipe plug valve with a one-way valve, comprising the following steps: S10, In the normal drilling circulation process, the drilling fluid flows downward in one direction from the upper fluid inlet. The fluid pressure applied by the drilling fluid to the inside of the one-way valve 7 overcomes the preload thrust of the spring 73, forcing the valve core 72 of the one-way valve to produce axial displacement. The internal flow channel of the one-way valve 7 is in a conducting state. The square drill pipe plug valve body 1 is in the open position under the maintenance of the pneumatic actuator 2, and the overall drilling fluid channel remains connected. S20, in the emergency shutdown process of a well kick, the downstream downhole fluid pressure surges upward in the opposite direction. The reverse fluid pressure and the preload of spring 73 work together to act on the one-way valve core 72. The one-way valve core 72 returns to its axial position towards the shut-off point and forms a fit, sealing the fluid channel. The one-way valve 7 first blocks the high-pressure fluid flowing upward in the opposite direction, cutting off most of the reverse flow pressure. S30, the operator issues a valve closing command through the control software in computer terminal 6, and computer terminal 6 sends the command data to PLC controller 4; S40, PLC controller 4 receives and parses instruction data, outputs trigger electrical signal to solenoid valve 3, the internal control coil of solenoid valve 3 is energized to generate magnetic force, attracts the internal component with piston 25 to move, and switches the internal gas flow channel. S50, after the gas flow channel is switched, the compressed air output by the filter pressure reducing valve 5 enters the designated chamber inside the pneumatic actuator 2 through the solenoid valve 3. The introduced compressed air drives the piston 25 inside the pneumatic actuator 2 to perform linear reciprocating motion. S60, the internal transmission mechanism of the pneumatic actuator 2 converts the linear motion of the piston 25 into the rotational motion of the output shaft 21. The output shaft 21 drives the valve stem 12 of the square drill pipe plug valve body 1 to rotate, and the valve stem 12 drives the valve core 13 to rotate synchronously to close the flow channel of the valve cavity, thus completing the remote shut-off action of the square drill pipe plug valve body 1.

[0027] See attached document Figure 2 , attached Figure 2 This is a flowchart illustrating the steps of a remote control method for a square drill pipe plug valve with a one-way valve according to an embodiment of the present invention; see attached... Figure 4 , attached Figure 4This is a structural diagram of a one-way valve assembly according to an embodiment of the present invention; see attached diagram. Figure 5 , attached Figure 5 This is a cross-sectional view of the normal working structure of a one-way valve assembly according to an embodiment of the present invention. In the remote control method for a square drill pipe plug valve with a one-way valve provided by the present invention, step S10 specifically includes the following sub-steps: S110, in this embodiment, the physical structure of the one-way valve 7 provides a basic channel for the forward flow of the system. The one-way valve 7 includes a one-way valve body 71, a one-way valve core 72, a spring 73, and a spring seat 74. The one-way valve body 71 forms a valve chamber that connects the upstream and downstream sides. The top of the valve chamber corresponds to the fluid inlet, and the bottom corresponds to the fluid outlet. A break is provided at the section contraction point of the inner wall of the valve chamber near the fluid inlet. The one-way valve core 72 is coaxially disposed inside the valve chamber in a manner that allows it to slide axially. The spring 73 is a wave spring, with its two ends abutting against the one-way valve core 72 and the spring seat 74, respectively. Compared with ordinary cylindrical helical springs, wave springs can effectively reduce the axial assembly height of the spring itself while providing the same preload and compression displacement. Using wave springs can effectively shorten the overall axial dimension of the one-way valve 7, which not only meets the overall goal of miniaturizing the square drill pipe plug valve system of this invention, but also effectively reduces the difficulty of installation and layout in the confined space of the wellhead. As a preferred approach, the adjustable preload of spring 73 can be achieved by machining an external thread on the outside of spring seat 74 and a matching internal thread on the inner wall of the tail of check valve body 71. By rotating to change the axial depth of spring seat 74 screwed into check valve body 71, the compression of spring 73 can be changed, thereby changing the initial axial preload of spring 73 applied to check valve core 72.

[0028] S120, During normal drilling circulation operations, drilling fluid enters the check valve body 71 from top to bottom through the fluid inlet. The drilling fluid generates a downward fluid thrust on the pressure-bearing surface at the top of the check valve core 72. According to the principle of force balance, the force condition for the positive opening of the check valve 7 satisfies the following relationship: ; in, The positive pressure of the drilling fluid at the fluid inlet; The effective cross-sectional area at the top of the check valve core 72 that bears the fluid pressure; The upward mechanical preload of spring 73; This refers to the frictional resistance generated between the valve core 72 of the one-way valve and the inner wall of the valve body when the valve core slides axially within the valve cavity.

[0029] This force condition expression clarifies the physical causal relationship between fluid pressure difference and internal mechanical resistance, with fluid pressure difference acting as a passive driving force. Typically, the setting of the forward opening pressure threshold is primarily based on the rated displacement of the mud pump and the bottom hole circulation conditions during drilling operations, achieved by adjusting the aforementioned mechanical preload. The value of is determined so that the system can trigger a mechanical response when the preset pressure threshold is reached.

[0030] S130, under continuous positive hydraulic pressure exceeding the preload, the check valve core 72 overcomes the spring force of the spring 73 and undergoes axial displacement downwards. At this time, a flow gap is established between the sealing side of the top of the check valve core 72 and the shut-off port in the valve cavity. After the drilling fluid passes through the shut-off port from the fluid inlet, it flows into the internal channel through the circular through-hole on the side wall of the check valve core 72 and is guided to the fluid outlet. Since the valve core 13 of the square drill pipe plug valve body 1 remains fully open at the top, and the check valve 7 remains open at the bottom due to the flow pressure, the overall fluid channel remains connected.

[0031] Considering that during normal drilling circulation, drilling fluid continuously flows over the shut-off point and into the circular through-hole on the side of the check valve core 72 at high speed, the drilling fluid containing solid rock cuttings will exert a strong scouring and cavitation effect on the outer surface of the check valve core 72. Therefore, its outer surface is covered with a wear-resistant layer. This wear-resistant layer effectively improves the surface's anti-wear capability, preventing surface deformation or damage to the check valve core 72 due to long-term scouring. This ensures that even in the event of an emergency well kick, the check valve core 72 can still form a tight seal after resetting to the shut-off point, guaranteeing the sealing reliability of the first cut-off barrier.

[0032] See attached document Figure 2 , attached Figure 2 This is a flowchart illustrating the steps of a remote control method for a square drill pipe plug valve with a one-way valve according to an embodiment of the present invention; see attached... Figure 4 , attached Figure 4 This is a structural diagram of a one-way valve assembly according to an embodiment of the present invention; see attached diagram. Figure 6 , attached Figure 6 This is a cross-sectional view of the reverse shut-off structure of a one-way valve assembly according to an embodiment of the present invention. In the remote control method for a square drill pipe plug valve with a one-way valve provided by the present invention, step S20 specifically includes the following sub-steps: S210, in this embodiment, when drilling operations encounter abnormal conditions such as well kick or blowout, the downhole fluid flow direction reverses, and the downstream high-pressure fluid flows upward back into the bottom region of the check valve body 71. At this time, the hydrodynamic force state of the check valve core 72 changes accordingly. To achieve the flow-closing response, a cooperative work mechanism of reverse fluid pressure and mechanical elasticity is established inside the check valve 7. Specifically, the closing driving force for the upward reset of the check valve core 72 satisfies the following relationship: ; in, The total closing driving force for driving the valve core 72 of the one-way valve to move upward to reset; The pressure of the fluid flowing upwards in the reverse direction from the wellbore; The effective cross-sectional area at the bottom of the one-way valve core 72 that bears the reverse flow pressure; This is the upward mechanical preload of spring 73.

[0033] This formula shows that under emergency conditions, the operation logic of the one-way valve 7 does not rely on external power input, but directly utilizes the reverse upward fluid pressure combined with the elastic restoring force of the spring 73 as the power source, forming a passive closing physical mechanism. In practical applications, The value of is usually determined by the abnormal high pressure of the formation and the pressure difference of the fluid column in the wellbore. Those skilled in the art can calibrate and match the relevant mechanical parameters of the above-mentioned closed driving force for blowout prevention based on the geological pressure prediction profile of the target drilling block.

[0034] S220, under the continuous action of the aforementioned total closing driving force, the one-way valve core 72 slides upward along the inner wall of the valve cavity. With this displacement, the top solid end face of the one-way valve core 72 advances to the shut-off position and forms surface contact with it. Accompanying this axial displacement, the circular through hole on the side of the one-way valve core 72 is blocked by the inner wall of the one-way valve body 71, thus disengaging from the fluid flow path. Based on this, the upstream and downstream fluid channels are physically isolated, and the one-way valve 72 thus forms a reverse shut-off state to intercept the reverse high-pressure fluid downhole.

[0035] S230, because the one-way valve 7 provides pre-cutoff capability, the pressure environment of the angular drill pipe plug valve body 1 is changed. After the one-way valve 7 establishes a flow barrier, the high-pressure fluid is isolated in the area below the one-way valve 7, so that the interior of the angular drill pipe plug valve body 1 is no longer directly exposed to the reverse high-pressure impact of the well blowout fluid. At this time, the working pressure difference in the valve cavity of the angular drill pipe plug valve body 1 is limited to the range of normal operating conditions. According to the valve fluid control principle, the frictional resistance between the valve core 13 and the sealing seat is mainly determined by the lateral positive pressure caused by the fluid working pressure difference. Therefore, the mechanical torque required for valve opening and closing is positively correlated with the fluid pressure difference borne by the internal valve core 13. Due to the decrease in the pressure difference across the valve core 13, the static overcoming torque required to drive the valve stem 12 to rotate is correspondingly reduced.

[0036] Based on the aforementioned correlation mechanism between fluid pressure load and mechanical actuation load, the pneumatic actuator 2 does not require a larger drive structure for extreme reverse high-pressure conditions. As a preferred option, the system can utilize a conventional double-acting pneumatic actuator 2 with a smaller cylinder volume and lower thrust parameters, coupled with a solenoid valve 3 for remote control. The pre-positioned unidirectional blowout preventer design avoids the system's peak torque requirements, reduces the overall size of external components, and lowers the total installation weight of the complete system. This optimized architecture not only facilitates wellhead space layout but also reduces fluid impact and internal component stress under extreme pressure conditions, thereby ensuring the square drill pipe plug valve body 1 has a stable and reliable shut-off capability under emergency conditions.

[0037] See attached document Figure 2 , attached Figure 2 This is a flowchart illustrating the steps of a remote control method for a square drill pipe plug valve with a one-way valve according to an embodiment of the present invention; see attached... Figure 3 , attached Figure 3 This is a schematic diagram showing the connection between a pneumatic actuator and a square drill pipe plug valve according to an embodiment of the present invention. In the remote control method for a square drill pipe plug valve with a check valve provided by the present invention, step S30 specifically includes the following sub-steps: S310, In this embodiment, based on the passive interception mechanism response, the system supports active control procedures executed through external manual intervention. The operator initiates the operation using a computer terminal 6 located far from the wellhead. A wired communication link is established between the network communication interface of the computer terminal 6 and the PLC controller 4 via an industrial network cable (e.g., based on Profinet or Modbus TCP industrial communication protocols). Considering the presence of electromagnetic interference sources such as motor start-stop at the drilling site, the wired communication architecture can shield external interference signals and maintain the stability of control data packet transmission. Compared to the shortcomings of wireless signals, which are prone to attenuation or disconnection in complex metal structures and large motor operating environments, the aforementioned wired communication architecture ensures that valve closing commands can be delivered to the field equipment with extremely low latency and zero packet loss rate in emergency situations. Based on this physical link, the operator can completely leave the dangerous wellhead area and, with only one person in front of a safe computer terminal, can reliably initiate control and confirm the status in real time, greatly ensuring personnel safety and the rapidity of system response.

[0038] In the S320 system deployment phase, technicians configure and compile the control program using computer terminal 6. The compiled preset control program is downloaded and stored in PLC controller 4 via the aforementioned wired communication link. As a preferred embodiment, this preset control program incorporates a logic conversion function to parse network instruction data from computer terminal 6 into corresponding underlying hardware trigger signals. For specific programming rules and the invocation of internal instruction blocks, those skilled in the art can refer to industrial control programming standards, which are well-known technologies in the field and will not be elaborated upon here.

[0039] In S330, during active flow control, the operator issues a valve closing command through the human-machine interface of computer terminal 6. Computer terminal 6 converts this command into a data message and sends it to PLC controller 4. Relying on online monitoring capabilities, the system synchronously establishes a status feedback mechanism. Computer terminal 6 periodically reads the internal status data of PLC controller 4 through the communication link, displaying the communication handshake status and command issuance feedback information on the interface. Based on the data interaction process, the system provides operators with confirmation of command execution status, achieving visualized monitoring of the system control process.

[0040] See attached document Figure 2 , attached Figure 2 This is a flowchart illustrating the steps of a remote control method for a square drill pipe plug valve with a one-way valve according to an embodiment of the present invention; see attached... Figure 3 , attached Figure 3 This is a schematic diagram showing the connection between a pneumatic actuator and a square drill pipe plug valve according to an embodiment of the present invention. In the remote control method for a square drill pipe plug valve with a check valve provided by the present invention, step S40 specifically includes the following sub-steps: S410, in this embodiment, after receiving the instruction data message from the computer terminal 6, the PLC controller 4 initiates the decoding process. Its internal microprocessor performs logical parsing of the instruction data according to a pre-set program. Based on the parsing result, the PLC controller 4 generates a corresponding trigger electrical signal through its internal digital output module, such as a 24V DC voltage signal commonly used in industrial control. This trigger electrical signal is transmitted via a laid control cable to the control terminal of the solenoid valve 3 installed outside the pneumatic actuator 2, thereby establishing an electrical connection between the control network and the field actuator.

[0041] S420. Considering the flammable gas environment at drilling sites, as a preferred approach, both the solenoid valve 3 and the pneumatic actuator 2 are designed with an explosion-proof structure. The pneumatic actuator 2 is a double-acting rack and pinion pneumatic actuator that meets explosion-proof requirements. The control coil and electrical contacts inside the solenoid valve 3 are encapsulated within a metal housing that meets explosion-proof requirements. When a trigger signal is applied to the terminals of the solenoid valve 3, the internal control coil is energized due to the current flowing through it, establishing a working magnetic field in the surrounding space. This process converts the control signal into magnetic force that drives the mechanical components.

[0042] S430, under the electromagnetic attraction generated by the working magnetic field, the moving iron core component with a piston inside the solenoid valve 3 is attracted. The generated electromagnetic attraction overcomes the fluid back pressure at the end of the component and the mechanical resistance of the internal spring 73, driving the moving iron core component to undergo axial displacement. Accompanying the displacement of the moving iron core component, its outer sealing structure and the inner wall of the valve body 11 undergo relative movement, thereby blocking the original exhaust channel and opening a new air inlet channel. Through this change in the internal coordination, the communication state between the various air inlets and exhaust ports inside the solenoid valve 3 is changed, completing the switching of the internal gas flow channels. The output direction of the air source is thus changed, guiding the control air pressure to the designated output channel. For the internal magnetic circuit design and specific sealing form of the solenoid valve, those skilled in the art can make conventional selections according to the required switching frequency and flow parameters, which are well known in the art and will not be described in detail here.

[0043] See attached document Figure 2 , attached Figure 2 This is a flowchart illustrating the steps of a remote control method for a square drill pipe plug valve with a one-way valve according to an embodiment of the present invention; see attached... Figure 3 , attached Figure 3 This is a schematic diagram showing the connection between a pneumatic actuator and a square drill pipe plug valve according to an embodiment of the present invention. In the remote control method for a square drill pipe plug valve with a check valve provided by the present invention, step S50 specifically includes the following sub-steps: S510, in this embodiment, considering the pressure fluctuations of the external compressed air source at the drilling site, a filter pressure reducing valve 5 is configured at the front end of the system for air source pretreatment. After the external compressed air source pipeline is connected to the inlet of the filter pressure reducing valve 5, the gas passes through the internal filter element to remove small solid particles and droplets, and then flows through the pressure reducing valve chamber. Through the mechanical balance between the force-bearing area of ​​the internal diaphragm and the elastic force of the pressure regulating spring 73, the gas with pressure fluctuations at the front end is converted into a low-pressure control air source that meets the set parameters. The processed compressed air is discharged from the outlet of the filter pressure reducing valve 5 to maintain the stability of the pressure at the inlet of the solenoid valve 3. As for the specific pressure regulating and filtering structure inside the filter pressure reducing valve, those skilled in the art can make conventional selections according to the on-site air source conditions, which are well known technologies in the field and will not be described in detail here.

[0044] S520, after the gas flow channel switching, the compressed air output from the filter pressure reducing valve 5 enters the designated chamber inside the pneumatic actuator 2 via the solenoid valve 3. Since the pneumatic actuator 2 adopts a double-acting cylinder structure, compressed air is alternately introduced and discharged through the air inlets A22 and B23 distributed on both sides of the housing. Specifically, the air inlet A22 of the pneumatic actuator 2 is connected to the air source output terminal OUT1 of the solenoid valve 3, and the air inlet B23 is connected to the air source output terminal OUT2 of the solenoid valve 3. A working pressure difference is established on both sides of the piston 25, driving the piston 25 to reciprocate linearly along the cylinder axis. During this process, the effective driving force generated by the pneumatic drive of the piston 25 satisfies the following relationship: ; in, This is the effective driving force for the axial movement of piston 25; This represents the absolute pressure of the compressed air currently in the intake chamber; This refers to the effective pressure-bearing area of ​​piston 25 on the intake side. This refers to the back pressure in the other chamber that is in the exhaust state; This refers to the effective pressure-bearing area of ​​piston 25 on the exhaust side. This is the frictional resistance between the piston 25 and the cylinder wall during linear motion.

[0045] This formula reflects the balance between work done and resistance within the pneumatic actuator. In practical applications, the air supply pressure set by the filter pressure reducing valve 5... It is necessary to overcome the system's no-load frictional resistance. The calculated effective driving force is based on the load force required for subsequent transmission by the mechanism. It's enough to propel the piston 25 forward.

[0046] S530, as a preferred embodiment, to limit the linear motion range of the piston 25, the end of the housing of the pneumatic actuator 2 is fitted with two limiting screws 24. When the piston 25 moves towards the end cover under pneumatic drive to the end of its stroke, the end face of the piston 25 will mechanically interfere with the end of the limiting screw 24 screwed into the cylinder, limiting further displacement of the piston 25. By externally adjusting the thread depth of the limiting screw 24, the position of the interference point inside the cylinder can be changed, thereby calibrating the mechanical stroke of the piston 25.

[0047] See attached document Figure 2 , attached Figure 2This is a flowchart illustrating the steps of a remote control method for a square drill pipe plug valve with a one-way valve according to an embodiment of the present invention; see attached... Figure 3 , attached Figure 3 This is a schematic diagram showing the connection between a pneumatic actuator and a square drill pipe plug valve according to an embodiment of the present invention. In the remote control method for a square drill pipe plug valve with a check valve provided by the present invention, step S60 specifically includes the following sub-steps: S610, in this embodiment, the linear motion of the piston 25 needs to be converted into a rotary motion for closing the valve. Based on the gear and rack transmission principle, the pneumatic actuator 2 is equipped with a corresponding transmission mechanism. The piston 25 has a rack structure machined on its side, which physically meshes with the gear in the center. As the piston 25 moves axially under pneumatic drive, the linear thrust of the rack forces the gear to rotate. This transmission process converts the effective driving force generated by the cylinder into rotational torque. To avoid limiting the protection range with a single mathematical expression, a specific formula is not used here. In essence, the magnitude of the mechanical torque output by the gear depends on the effective driving force of the piston 25 moving axially, the pitch circle radius of the gear, and the mechanical efficiency during the gear and rack meshing transmission process. In actual engineering, considering the machining accuracy of the tooth surface and the internal lubrication condition, the value of this mechanical transmission efficiency is usually set between 0.90 and 0.98. In practical implementation, those skilled in the art can reasonably select the pitch circle diameter of the gear and the corresponding rack parameters according to the required shut-off torque of the square drill pipe plug valve body 1 under normal pressure conditions, so as to ensure that the output torque covers the resistance requirements for valve closure.

[0048] S620, the central hole of the gear is mechanically connected to the valve stem 12 of the square drill pipe plug valve body 1 via a keyway or spline, establishing a detachable rigid connection to achieve circumferential positioning and ensure the stability of power transmission. As a preferred method, the internal axial mechanical stroke of the pneumatic actuator 2 is systematically matched with the pitch circle parameters of the gear; that is, the maximum linear displacement of the piston 25 is designed to be equal to 1 / 4 of the circumference of the gear's pitch circle. Through this geometric mapping relationship, the complete stroke of the piston 25 from the cylinder's starting end to the position of the limit screw 24 corresponds to a transmission displacement that is precisely converted into a 90° angular displacement of the gear and valve stem 12. Based on the rotation of the valve stem 12, the valve core 13 located inside the square drill pipe plug valve body 1 rotates synchronously. For the dynamic sealing support structure between the valve stem 12 and the valve body 11, those skilled in the art can use conventional O-rings or V-type combination seals, which are well-known technologies in the field and will not be elaborated upon here.

[0049] In S630, with the 90° rotation of valve core 13, its internal central flow channel intersects with the drilling fluid flow direction. The solid side of valve core 13 gradually covers and fits against the flow hole of the valve seat, thereby cutting off the internal main fluid channel. At this stage, because the check valve has already acted and intercepted the reverse high-pressure fluid when encountering abnormal downhole conditions, the fluid pressure difference between the upper and lower ends of valve core 13 during the rotation and closing process is limited to the normal safe range. This load decoupling condition avoids interference and severe friction on the sealing surface caused by high pressure difference, reduces the mechanical wear rate of valve core 13 and related transmission components, and ensures the operational reliability of the angular drill pipe plug valve under pressure.

Claims

1. A remote control system for a square drill pipe plug valve with a one-way valve, characterized in that, It includes a square drill pipe plug valve body (1), a pneumatic actuator (2), a solenoid valve (3), a PLC controller (4), a computer terminal (6), and a check valve (7); The square drill pipe plug valve body (1) and the one-way valve (7) are coaxially connected in series to form a downhole fluid channel. The one-way valve (7) is located downstream of the fluid discharge side of the square drill pipe plug valve body (1). The pneumatic actuator (2) is installed on the outer housing of the square drill pipe plug valve body (1), and the output shaft (21) of the pneumatic actuator (2) is connected to the valve stem (12) of the square drill pipe plug valve body (1). The solenoid valve (3) is installed on the outside of the pneumatic actuator (2), and the air source output end of the solenoid valve (3) is connected to the air inlet of the pneumatic actuator (2). The network communication interface of the PLC controller (4) is connected to the computer (6) to establish a wired communication link, and the signal output terminal of the PLC controller (4) is connected to the control coil inside the solenoid valve (3).

2. The remote control system for a square drill pipe plug valve with a one-way valve according to claim 1, characterized in that, It also includes a filter pressure reducing valve (5), the outlet of which is connected to the air source input pipeline of the solenoid valve (3).

3. The remote control system for a square drill pipe plug valve with a one-way valve according to claim 1, characterized in that, The one-way valve (7) includes a one-way valve body (71), a one-way valve core (72), a spring (73), and a spring seat (74). The valve body (71) of the one-way valve has a through-hole forming a valve cavity that connects the upstream and downstream. The valve cavity has a break at the section contraction near the fluid inlet on the inner wall. The one-way valve core (72) is coaxially disposed inside the valve cavity, and a circular through hole is provided on the one-way valve core (72); The two ends of the spring (73) abut against the one-way valve core (72) and the spring seat (74), respectively.

4. The remote control system for a square drill pipe plug valve with a one-way valve according to claim 3, characterized in that, When the one-way valve core (72) is located away from the shut-off port, there is a flow gap between the end face of the one-way valve core (72) and the shut-off port, and the circular through hole is not blocked by the inner wall of the one-way valve body (71).

5. A remote control system for a square drill pipe plug valve with a one-way valve according to claim 3, characterized in that, When the one-way valve core (72) is positioned close to the shut-off port, the end face of the one-way valve core (72) and the shut-off port form a surface fit, and the circular through hole is blocked by the inner wall of the one-way valve body (71).

6. The remote control system for a square drill pipe plug valve with a one-way valve according to claim 3, characterized in that, The spring seat (74) has an external thread on its outer side, and the inner wall of the tail of the one-way valve body (71) has a matching internal thread. The spring seat (74) is connected to the tail of the one-way valve body (71) by the external thread and the internal thread.

7. The remote control system for a square drill pipe plug valve with a one-way valve according to claim 1, characterized in that, The pneumatic actuator (2) has an air inlet A (22) and an air inlet B (23) on both sides of its housing. The pneumatic actuator (2) is equipped with a piston (25) and a gear inside; The piston (25) has a rack structure machined on its side, and the rack structure physically meshes with the gear; The central hole of the gear is rigidly connected to the output shaft (21).

8. A remote control system for a square drill pipe plug valve with a one-way valve according to claim 7, characterized in that, The housing end of the pneumatic actuator (2) is fitted with a limiting screw (24), the end of which extends into the cylinder of the pneumatic actuator (2) and forms mechanical interference with the end face of the piston (25).

9. A remote control system for a square drill pipe plug valve with a one-way valve according to claim 1, characterized in that, The square drill pipe plug valve body (1) includes a valve body (11), a valve stem (12), a valve core (13), and a connecting thread (14). The valve core (13) is disposed inside the valve body (11), and one end of the valve stem (12) is connected to the valve core (13); The connecting thread (14) at the end of the one-way valve (7) is fixedly connected to the connecting thread (14) at the bottom of the square drill pipe plug valve body (1).

10. A remote control system for a square drill pipe plug valve with a one-way valve according to claim 1, characterized in that, The solenoid valve (3) is provided with a moving iron core component with a piston inside, and the moving iron core component with a piston is located within the working magnetic field range of the control coil.

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