A main pliers hydraulic control system of an opening power pliers clamped by a hydraulic cylinder and its control method

Abstract

The present invention relates to a main clamp hydraulic control system of an open type power tong clamped by a hydraulic cylinder and a control method thereof, which comprises a tong body, a clamp head clamped by a hydraulic cylinder, a hydraulic motor, a manual reversing combined valve, a quick-connect combined assembly, a pressure relief device, a flow splitting and pressure maintaining device, a quick-connect mechanical interlock protection device, a make-up and break-out direction protection device, a quick-connect hydraulic interlock protection device and a hydraulic boosting device. The pressure relief device, the flow splitting and pressure maintaining device, the hydraulic boosting device and a male combined joint are arranged on the clamp head clamped by the hydraulic cylinder; the manual reversing combined valve, the quick-connect mechanical interlock protection device, the make-up and break-out direction protection device, the quick-connect hydraulic interlock protection device and a female combined joint are arranged on the tong body. The present invention provides a pluggable oil supply and return oil system and a pressure relief device with an accumulator for the main clamp of the open type power tong clamped by the hydraulic cylinder to meet the requirements of the rotation of the oil supply and return oil of the clamp head clamping mechanism; and adopts multi-faceted safety guarantee measures to ensure the safety and reliability of the operation, and has stable operation, safety and reliability.

Description

Technical Field

[0001] The present invention relates to a power tong for oilfield pipes, in particular to a main tong hydraulic control system of an open power tong suitable for clamping by a hydraulic cylinder, belonging to the technical field of design and manufacture of petroleum equipment. Background Art

[0002] In the make-up and break-out of the threads of oil pipes, casing pipes, and drill pipes at the oilfield wellhead, a power tong for pipes is used. It is generally divided into a main tong and a back tong. The back tong clamps the lower part of the pipe string and does not rotate, and the main tong clamps the upper part of the pipe string and rotates to perform the make-up or break-out operation. Usually, the jaws of the main tong of the power tong are driven by an eccentric wheel to clamp the pipe string to transmit torque. It climbs and clamps during the rotation process. In actual application, due to the wear of the jaws and the clamping mechanism and the dimensional deviation, the clamping reliability is unstable, and slipping often occurs. In contrast, the direct clamping structure of the hydraulic cylinder is more reliable. When using the direct clamping structure of the hydraulic cylinder, special hydraulic control is required and the operation safety needs to be ensured. Summary of the Invention

[0003] The purpose of the present invention is to provide a main tong hydraulic control system of an open power tong clamped by a hydraulic cylinder and its control method to solve the problems of hydraulic control operation and safety protection of the main tong hydraulic cylinder clamping structure of the hydraulic power tong.

[0004] To achieve the above purpose, the present invention is implemented through the following technical solutions: A main tong hydraulic control system of an open power tong clamped by a hydraulic cylinder includes a tong body, a hydraulic cylinder clamping type tong head, a hydraulic motor, a manual reversing combination valve, a quick-connect combination assembly, a pressure relief device, a flow splitting and pressure maintaining device, a quick-connect mechanical interlock protection device, a make-up and break-out direction protection device, a quick-connect hydraulic interlock protection device, and a hydraulic boosting device. The hydraulic cylinder clamping type tong head is arranged at the front of the tong body and includes a tong head opening large gear, a clamping mechanism, and a hydraulic clamping cylinder. The hydraulic clamping cylinder drives the clamping mechanism to clamp the pipe string. The hydraulic motor is arranged at the rear of the tong body to transmit power to the tong head opening large gear. The manual reversing combination valve includes a first manual reversing valve, a second manual reversing valve, and a third manual reversing valve. The quick-connect combination assembly includes a male combination joint, a female combination joint, and a wrench. By operating the wrench, the male combination joint and the female combination joint are separated or connected. The pressure relief device, the flow splitting and pressure maintaining device, and the male combination joint are arranged on the hydraulic cylinder clamping type tong head. The manual reversing combination valve, the quick-connect mechanical interlock protection device, the make-up and break-out direction protection device, the quick-connect hydraulic interlock protection device, and the female combination joint are arranged on the tong body.

[0005] The first manual reversing valve is connected to the oil port of the hydraulic motor to form a hydraulic motor control circuit to control the forward and reverse rotation of the hydraulic motor, driving the hydraulic cylinder clamping type tong head to rotate. Among them, when pushing the first manual reversing valve, the hydraulic cylinder clamping type tong head rotates in the make-up direction, and when pulling the first manual reversing valve, the hydraulic cylinder clamping type tong head rotates in the break-out direction.

[0006] The second manual reversing valve is connected with the hydraulic clamping cylinder through the quick-connect combination assembly, the flow diverter and pressure maintaining device, and the hydraulic booster to form a hydraulic clamping cylinder control circuit; the flow diverter and pressure maintaining device is arranged between one oil port of the second manual reversing valve and the rodless chamber of the hydraulic clamping cylinder, and it is composed of a flow diverter valve and a hydraulically controlled one-way valve; the hydraulic booster is arranged in parallel in the oil circuit between the flow diverter and pressure maintaining device and the male combination joint, one outlet of the male combination joint is connected with the oil inlet of the hydraulic booster, and the other outlet is connected with the oil inlet of the hydraulically controlled one-way valve in the flow diverter and pressure maintaining device; the liquid flow direction of the hydraulically controlled one-way valve points to the hydraulic clamping cylinder, and its outlet The oil port is connected with the oil inlet of the diverter valve, and its hydraulic control port is connected with the male combination joint connected to the other oil port of the second manual reversing valve. The two oil outlets of the diverter valve are respectively connected with the rodless chambers of the two hydraulic clamping cylinders, and the oil inlet of the diverter valve is simultaneously connected with the oil outlet of the hydraulic booster device; the other oil port of the second manual reversing valve is connected with the rod chamber of the hydraulic clamping cylinder through the quick-connect combination assembly; when the second manual reversing valve is pushed, the hydraulic oil is pressurized and flows to the rodless chamber of the hydraulic clamping cylinder through the diverter pressure-maintaining device, and the hydraulic clamping cylinder extends; when the second manual reversing valve is pulled, the hydraulic oil flows to the rod chamber of the hydraulic clamping cylinder, and the hydraulic clamping cylinder retracts;

[0007] The pressure relief device is arranged in the oil circuit between one oil port of the second manual reversing valve and the rodless chamber of the hydraulic clamping cylinder, forming a pressure relief circuit of the rodless chamber of the hydraulic cylinder to release the pressure in the rodless chamber of the hydraulic clamping cylinder; the pressure relief device is composed of a ball valve and a gas-isolated accumulator, wherein the oil inlet of the ball valve is connected to the oil circuit between the hydraulic-controlled one-way valve and the diverter valve in the diverter pressure-maintaining device, and the oil outlet is connected to the oil port of the gas-isolated accumulator and the rod chamber of the hydraulic clamping cylinder; the pressure relief device is to solve the problem of buckling The problem that the opening of the hydraulic cylinder clamping pliers cannot be properly centered and reset during operation: When the make-up reaches the set torque and the pipe thread has been tightened, the hydraulic cylinder clamping pliers stop rotating and stop at any position of 360°, while the hydraulic clamping cylinder is still in the pressure-maintaining state and always holds the pipe. If the opening of the hydraulic cylinder clamping pliers is to be centered, either continue to rotate beyond the set make-up torque value and damage the thread, or rotate in the opposite direction to loosen the tightened thread. Such operation is not allowed. Therefore, when the rodless chamber of the hydraulic clamping cylinder needs to be depressurized, the ball valve is opened to allow the pressure oil in the rodless chamber of the hydraulic clamping cylinder to flow to the rod chamber and the gas-isolated accumulator to unload the pressure. At this time, the clamping mechanism driven by the hydraulic cylinder is in a loosened state, thereby facilitating the operation of rotating the clamping head of the hydraulic cylinder to center the opening. After the rodless chamber of the hydraulic clamping cylinder is unloaded, the ball valve is closed to cut off the oil circuit between the rodless chamber of the hydraulic clamping cylinder and the rod chamber and the gas-isolated accumulator, and the hydraulic clamping cylinder returns to normal working state.

[0008] The quick-connect mechanical interlock protection device includes a quick-connect combination assembly, a connecting cable, a flexible shaft, a bracket, a spring, and a flexible shaft gate valve. One end of the flexible shaft is connected to the wrench in the quick-connect combination assembly through the connecting cable, and the other end is connected to the flexible shaft gate valve. The bracket is fixed to the flexible shaft gate valve. The spring is sleeved in the flexible shaft and abuts between the bracket and the flexible shaft gate valve.

[0009] The make-and-break direction protection device includes a third manual reversing valve and two pilot-operated check valves. The third manual reversing valve is included in the manual reversing combination valve. The two pilot-operated check valves are respectively connected in series at the inlet and outlet ports of the hydraulic motor in the hydraulic motor control circuit. The flow direction of the pilot-operated check valves both points to the hydraulic motor. The two oil ports of the third manual reversing valve are respectively connected to the pilot ports on the two pilot-operated check valves. When the spool in the third manual reversing valve is in the middle position, both pilot-operated check valves are in the closed state, and the oil circuit of the hydraulic motor control circuit is blocked. Push the third manual reversing valve, and the hydraulic oil flows from one working oil port of the third manual reversing valve to the pilot port of one pilot-operated check valve. This oil circuit opens a two-way passage. The pilot port of the other pilot-operated check valve is connected to the return oil of the hydraulic control system through the other working oil port of the third manual reversing valve. The oil circuit where it is located is unidirectionally closed and unidirectionally open. Only the oil circuit rotating in the make-up direction in the hydraulic motor control circuit is open, and the oil circuit rotating in the break-out direction is closed. Conversely, pull the third manual reversing valve, and only the oil circuit rotating in the break-out direction in the hydraulic motor control circuit is open, and the oil circuit rotating in the make-up direction is closed.

[0010] Another implementation scheme in the make-and-break direction protection device is that the third manual reversing valve is connected in parallel in the hydraulic motor control circuit to form a secondary control oil circuit of the hydraulic motor with the two pilot-operated check valves. The inlet and outlet ports of the third manual reversing valve are respectively connected to the inlet and return oil circuits of the hydraulic motor control circuit, and its working ports are respectively connected to the pilot ports of the two pilot-operated check valves. When the spool in the third manual reversing valve is in the middle position, both pilot-operated check valves are in the closed state, and the oil circuit of the hydraulic motor control circuit is blocked. Push the third manual reversing valve, and the hydraulic oil flows from one working oil port of the third manual reversing valve to the pilot port of one pilot-operated check valve. This oil circuit opens a two-way passage, and the pilot port of the other pilot-operated check valve is closed and blocked. The oil circuit where it is located is unidirectionally closed and unidirectionally open. Only the oil circuit rotating in the make-up direction in the hydraulic motor control circuit is open, and the oil circuit rotating in the break-out direction is closed. Conversely, pull the third manual reversing valve, and only the oil circuit rotating in the break-out direction in the hydraulic motor control circuit is open, and the oil circuit rotating in the make-up direction is closed.

[0011] The make-and-break direction protection device ensures that only one of the continuous push or pull operations of the first manual reversing valve controlling the hydraulic motor is effective. There is only an oil passage for the hydraulic motor to rotate in one direction, while the oil passage for the other rotation direction is blocked, preventing the wrong operation of reverse rotation and unthreading when pulling the first manual reversing valve before the pipe thread is tightened and the rodless cavity of the hydraulic clamping cylinder has not been depressurized during the threading operation. If it is necessary to switch to the other rotation direction, it is required to manually switch the position of the spool in the third manual reversing valve.

[0012] The quick-connect hydraulic interlock protection device includes a quick-connect combination assembly and two pilot-operated check valves in the make-and-break direction protection device. The female combination joints on the quick-connect combination assembly are respectively connected to the pilot ports of the two pilot-operated check valves and the oil return port of the hydraulic control system, and their corresponding male combination joints converge at one place and are connected. The quick-connect mechanical interlock protection device and the quick-connect hydraulic interlock protection device provide double protection for the quick-connect combination assembly: when operating the wrench to connect or separate the female combination joint and the male combination joint, when the quick-connect combination assembly is connected, the wrench pulls the flexible shaft to drive the flexible shaft gate valve to change direction, and the control circuit of the hydraulic motor is in the unloading state. At the same time, the pilot ports of the two pilot-operated check valves in the make-and-break direction protection device are connected to the oil return port of the hydraulic control system, and the two pilot-operated check valves are closed, cutting off the oil passage leading to the hydraulic motor. The control circuit of the hydraulic motor is in the unloading and locked state, ensuring that the hydraulic motor cannot rotate when the quick-connect combination assembly is connected, and avoiding potential safety hazards caused by misoperation. When the quick-connect combination assembly is separated, the spring in the quick-connect mechanical interlock protection device pushes the flexible shaft gate valve back to its original position. At the same time, the pilot ports of the two pilot-operated check valves in the make-and-break direction protection device are not affected by the quick-connect combination assembly, and the control circuit of the hydraulic motor is in the normal working state.

[0013] Preferably, a positioning device is provided on the spool of the third manual reversing valve. After operating the third manual reversing valve, its spool can be positioned at a fixed position.

[0014] Preferably, the hydraulic boosting device and the flow splitting and pressure maintaining device are integrated into an integral valve group.

[0015] Another implementation of the oil port connection of the gas isolation type accumulator in the pressure relief device is that its oil port is directly connected to the oil tank to directly release the pressure in the hydraulic clamping cylinder.

[0016] Preferably, the number of hydraulic clamping cylinders is one, two or more. When it is one, the oil outlet of the pilot-operated check valve is directly connected to the rodless cavity of the hydraulic clamping cylinder. When it is two or more, the number of oil outlets of its flow splitting valve is correspondingly two or more.

[0017] The specific operation method of this technical solution is:

[0018] Step 1. Operation of clamping the pipe string: Push the main tong of the power tong to the center of the pipe string, and then operate the wrench to connect the female combined joint with the male combined joint. At this time, protected by the double protection of the quick-connect mechanical interlock protection device and the quick-connect hydraulic interlock protection device, the control circuit of the hydraulic motor is in the unloading and locked state; Push the second manual reversing valve. After the hydraulic oil is pressurized, it is supplied to the rodless chambers of the two hydraulic clamping cylinders through the flow-dividing and pressure-holding device, driving the hydraulic cylinder clamping type tong head to clamp the pipe string; Operate the second manual reversing valve to return to the middle position. The flow-dividing and pressure-holding device keeps the pressure oil in the rodless chambers of the hydraulic clamping cylinders to maintain the clamping of the pipe string; Then operate the wrench to separate the female combined joint from the male combined joint. The quick-connect mechanical interlock protection device and the quick-connect hydraulic interlock protection device are unlocked at the same time. At this time, the rotation direction of the hydraulic motor is restricted by the make-up and break-out direction protection device, and the next make-up or break-out operation is selected according to the operation requirements.

[0019] Step 2. Make-up and break-out operation:

[0020] a. Make-up operation: Push the third manual reversing valve to the make-up control direction, and then push the first manual reversing valve. The hydraulic motor rotates, and the hydraulic cylinder clamping type tong head clamps the pipe string and rotates in the make-up direction until the make-up torque reaches the set value and stops rotating; Operate the first manual reversing valve to return to the middle position, operate the ball valve to open, unload the pressure oil kept in the rodless chamber of the hydraulic clamping cylinder and then close the ball valve, and then pull the first manual reversing valve to make the hydraulic cylinder clamping type tong head rotate in the reverse direction until its opening is centered.

[0021] b. Break-out operation: Pull the third manual reversing valve to the break-out control direction, and then pull the first manual reversing valve. The hydraulic motor rotates in the reverse direction, and the hydraulic cylinder clamping type tong head clamps the pipe string and rotates in the break-out direction until the upper and lower pipe strings are separated. Continue to pull the first manual reversing valve, and the hydraulic cylinder clamping type tong head continues to rotate until the opening is centered.

[0022] Step 3. Reset operation of the clamping mechanism: Finally, operate the wrench to connect the female combined joint with the male combined joint, pull the second manual reversing valve, supply oil to the rod chamber of the hydraulic clamping cylinder, the single rod of the hydraulic clamping cylinder retracts, and the clamping mechanism driven by the hydraulic cylinder loosens; Operate the second manual reversing valve to return to the middle position. The rodless chamber and the rod chamber of the hydraulic clamping cylinder are both connected to the return oil of the hydraulic control system, and the gas-isolated accumulator discharges the stored hydraulic oil to prepare for the next oil storage; The main tong of the power tong leaves the center of the pipe string, and one make-up or break-out operation is completed.

[0023] The present invention provides a pluggable oil supply and return system and a pressure relief device with an accumulator for the open power tong main tong clamped by a hydraulic cylinder to meet the rotation oil supply and return needs of the tong head clamping mechanism; Adopt multi-faceted safety guarantee measures to ensure the safety and reliability of the operation, with stable operation, safety and reliability, and great economic and social benefits. Description of the Drawings

[0024] Figure 1 is the front view of the present invention;

[0025] Figure 2 is the top view of the present invention;

[0026] Figure 3 is the top view (section view) of the hydraulic cylinder clamping type jaw of the present invention;

[0027] Figure 4 is the hydraulic schematic diagram of the present invention;

[0028] Figure 5 is the schematic diagram (partial view) of the quick-connect mechanical interlock protection device when the quick-connect combination assembly is separated;

[0029] Figure 6 is the schematic diagram of another implementation scheme of the make-up and break-out direction protection device of the present invention;

[0030] Figure 7 is the schematic diagram of another implementation scheme of the oil port connection of the gas isolation type accumulator in the pressure relief device of the present invention.

[0031] In the figure: 1. jaw body; 2. hydraulic cylinder clamping type jaw; 201. large gear for jaw opening; 202. clamping mechanism; 203. hydraulic clamping cylinder; 3. hydraulic motor; 4. manual reversing combination valve; 401. first manual reversing valve; 402. second manual reversing valve; 403. third manual reversing valve; 5. quick-connect combination assembly; 501. male combination joint; 502. female combination joint; 503. wrench; 6. pressure relief device; 601. ball valve; 602. gas isolation type accumulator; 7. flow splitting and pressure maintaining device; 701. flow splitting valve; 702. pilot-operated check valve; 8. quick-connect mechanical interlock protection device; 801. connecting cable; 802. flexible shaft; 803. bracket; 804. spring; 805. flexible shaft gate valve; 9. make-up and break-out direction protection device; 901. pilot-operated check valve; 10. quick-connect hydraulic interlock protection device; 11. hydraulic boosting device. Specific embodiments

[0032] The present invention will be further explained and illustrated with reference to the accompanying drawings as follows:

[0033] Such as Figures 1 - 5As shown in the figure, the present invention includes a pliers body 1, a hydraulic cylinder clamping pliers head 2, a hydraulic motor 3, a manual reversing combination valve 4, a quick-connect combination assembly 5, a pressure relief device 6, a flow splitting and pressure maintaining device 7, a quick-connect mechanical interlock protection device 8, a make-up and break-out direction protection device 9, a quick-connect hydraulic interlock protection device 10, and a hydraulic boosting device 11. The hydraulic cylinder clamping pliers head 2 is arranged at the front part of the pliers body 1 and includes a pliers head opening large gear 201, a clamping mechanism 202, and a hydraulic clamping cylinder 203. The hydraulic clamping cylinder 203 drives the clamping mechanism 202 to clamp the pipe string. The hydraulic motor 3 is arranged at the rear part of the pliers body 1 to transmit power to the pliers head opening large gear 201. The manual reversing combination valve 4 includes a first manual reversing valve 401, a second manual reversing valve 402, and a third manual reversing valve 403. The quick-connect combination assembly 5 includes a male combination joint 501, a female combination joint 502, and a wrench 503. By operating the wrench 503, the male combination joint 501 and the female combination joint 502 are separated or connected. The pressure relief device 6, the flow splitting and pressure maintaining device 7, and the male combination joint 501 are arranged on the hydraulic cylinder clamping pliers head 2. The manual reversing combination valve 4, the quick-connect mechanical interlock protection device 8, the make-up and break-out direction protection device 9, the quick-connect hydraulic interlock protection device 10, and the female combination joint 502 are arranged on the pliers body 1.

[0034] The first manual reversing valve 401 is connected to the oil port of the hydraulic motor 3 to form a hydraulic motor control circuit, which controls the forward and reverse rotation of the hydraulic motor 3 to drive the hydraulic cylinder clamping pliers head 2 to rotate. When the first manual reversing valve 401 is pushed, the hydraulic cylinder clamping pliers head 2 rotates in the make-up direction. When the first manual reversing valve 401 is pulled, the hydraulic cylinder clamping pliers head 2 rotates in the break-out direction.

[0035] The second manual reversing valve 402 is connected to the hydraulic clamping cylinder 203 through the quick-connect combination assembly 5, the flow-dividing pressure-holding device 7, and the hydraulic boosting device 11 to form a control circuit for the hydraulic clamping cylinder. The flow-dividing pressure-holding device 7 is arranged between one oil port of the second manual reversing valve 402 and the rodless cavity of the hydraulic clamping cylinder 203, and it consists of a flow-dividing valve 701 and a pilot-operated check valve 702. The hydraulic boosting device 11 is arranged in parallel in the oil circuit between the flow-dividing pressure-holding device 7 and the male combination joint 501. One outlet of the male combination joint 501 is connected to the oil inlet of the hydraulic boosting device 11, and the other outlet is connected to the oil inlet of the pilot-operated check valve 702 in the flow-dividing pressure-holding device 7. The flow direction of the pilot-operated check valve 702 points to the hydraulic clamping cylinder 203, its oil outlet is connected to the oil inlet of the flow-dividing valve 701, its pilot control port is connected to the male combination joint 501 connecting the other oil port of the second manual reversing valve 402, the two oil outlets of its flow-dividing valve 701 are respectively connected to the rodless cavities of the two hydraulic clamping cylinders 203, and the oil inlet of its flow-dividing valve 701 is simultaneously connected to the oil outlet of the hydraulic boosting device 11. The other oil port of the second manual reversing valve 402 is connected to the rod chamber of the hydraulic clamping cylinder 203 through the quick-connect combination assembly 5. When the second manual reversing valve 402 is pushed, the hydraulic oil is boosted and flows to the rodless cavity of the hydraulic clamping cylinder 203 through the flow-dividing pressure-holding device 7, and the hydraulic clamping cylinder 203 extends. When the second manual reversing valve 402 is pulled, the hydraulic oil flows to the rod chamber of the hydraulic clamping cylinder 203, and the hydraulic clamping cylinder 203 retracts.

[0036] The pressure relief device is arranged in the oil circuit between one oil port of the second manual reversing valve 402 and the rodless cavity of the hydraulic clamping cylinder 203, forming a pressure relief circuit for the rodless cavity of the hydraulic cylinder to release the pressure in the rodless cavity of the hydraulic clamping cylinder 203. The pressure relief device consists of a ball valve 601 and a gas-isolated accumulator 602. The oil inlet of the ball valve 601 is connected to the oil circuit between the hydraulic control check valve 702 and the flow dividing valve 701 in the flow dividing and pressure maintaining device 7, and its oil outlet is connected to the oil port of the gas-isolated accumulator 602 and the rodless cavity of the hydraulic clamping cylinder 203. The pressure relief device is to solve the problem that the opening of the hydraulic cylinder clamping tong head 2 cannot be normally centered and reset during the make-up operation: when the make-up reaches the set torque and the pipe thread has been made up, at this time the hydraulic cylinder clamping tong head 2 stops rotating and stops at any position of 360°, while the hydraulic clamping cylinder 203 is still in the pressure maintaining state and always holds the pipe tightly. If the opening of the hydraulic cylinder clamping tong head 2 is to be centered, either continue to rotate beyond the set make-up torque value to damage the thread, or reverse rotate to loosen the made-up thread, such operations are not allowed. Therefore, when the rodless cavity of the hydraulic clamping cylinder 203 needs to be depressurized, open the ball valve 601 to make the pressure oil in the rodless cavity of the hydraulic clamping cylinder 203 flow to the rodless cavity and the gas-isolated accumulator 602 to unload. At this time, the clamping mechanism 202 driven by the hydraulic cylinder is in the loosened state, so as to conveniently operate the rotation of the hydraulic cylinder clamping tong head 2 to center the opening. After the rodless cavity of the hydraulic clamping cylinder 203 is unloaded, close the ball valve 601 to cut off the oil circuit between the rodless cavity of the hydraulic clamping cylinder 203 and the rodless cavity and the gas-isolated accumulator 602, and the hydraulic clamping cylinder 203 returns to the normal working state.

[0037] The quick-connect mechanical interlock protection device 8 includes a quick-connect combination assembly 5, a connecting cable 801, a flexible shaft 802, a bracket 803, a spring 804 and a flexible shaft gate valve 805. One end of the flexible shaft 802 is connected to the wrench 503 in the quick-connect combination assembly 5 through the connecting cable 801, and the other end is connected to the flexible shaft gate valve 805. The bracket 803 is fixed to the flexible shaft gate valve 805, and the spring 804 is arranged in series in the flexible shaft 802 and abuts between the bracket 803 and the flexible shaft gate valve 805.

[0038] The make-and-break direction protection device 9 includes a third manual reversing valve 403 and two pilot-operated check valves 901. The third manual reversing valve 403 is included in the manual reversing combination valve 4. The two pilot-operated check valves 901 are respectively connected in series at the inlet and return oil ports of the hydraulic motor 3 in the hydraulic motor control circuit. The fluid flow directions of the pilot-operated check valves 901 both point to the hydraulic motor 3. The two oil ports of the third manual reversing valve 403 are respectively connected to the pilot ports on the two pilot-operated check valves 901. When the spool in the third manual reversing valve 403 is in the middle position, the two pilot-operated check valves 901 are both in the closed state, and the oil circuit of the hydraulic motor control circuit is not connected. Push the third manual reversing valve 403, and the hydraulic oil flows from one working oil port of the third manual reversing valve 403 to the pilot port of one pilot-operated check valve 901. This oil circuit opens for two-way flow, and the pilot port of the other pilot-operated check valve 901 is connected to the return oil of the hydraulic control system through the other working oil port of the third manual reversing valve 403. The oil circuit where it is located is unidirectionally closed for one-way flow. Only the oil circuit rotating in the make-up direction in the hydraulic motor control circuit is connected, and the oil circuit rotating in the break-out direction is closed. Conversely, pull the third manual reversing valve 403, and only the oil circuit rotating in the break-out direction in the hydraulic motor control circuit is connected, and the oil circuit rotating in the make-up direction is closed.

[0039] As Figure 6 shown, another implementation of the make-and-break direction protection device 9 is: The third manual reversing valve 403 is connected in parallel in the hydraulic motor control circuit to form a secondary control oil circuit for the hydraulic motor 3 with the two pilot-operated check valves 901. The inlet and return oil ports of the third manual reversing valve 403 are respectively connected to the inlet and return oil circuits of the hydraulic motor control circuit, and its working ports are respectively connected to the pilot ports of the two pilot-operated check valves 901. When the spool in the third manual reversing valve 403 is in the middle position, the two pilot-operated check valves 901 are both in the closed state, and the oil circuit of the hydraulic motor control circuit is not connected. Push the third manual reversing valve 403, and the hydraulic oil flows from one working oil port of the third manual reversing valve 403 to the pilot port of one pilot-operated check valve 901. This oil circuit opens for two-way flow, and the pilot port of the other pilot-operated check valve 901 is closed and not connected. The oil circuit where it is located is unidirectionally closed for one-way flow. Only the oil circuit rotating in the make-up direction in the hydraulic motor control circuit is connected, and the oil circuit rotating in the break-out direction is closed. Conversely, pull the third manual reversing valve 403, and only the oil circuit rotating in the break-out direction in the hydraulic motor control circuit is connected, and the oil circuit rotating in the make-up direction is closed.

[0040] The make and break direction protection device 9 ensures that only one of the continuous push or pull operations of the first manual reversing valve 401 that controls the hydraulic motor 3 is effective. There is only an oil passage for the hydraulic motor 3 to rotate in one direction, while the oil passage for the other rotation direction is blocked, preventing the incorrect operation of reverse rotation and unthreading when the pipe thread has been properly made up during the make-up operation, but the rodless cavity of the hydraulic clamping cylinder 203 has not been depressurized yet and the first manual reversing valve 401 is pulled. To switch to the other rotation direction, it is necessary to manually switch the position of the spool in the third manual reversing valve 403.

[0041] The quick-connect hydraulic interlock protection device 10 includes the quick-connect combination assembly 5 and two pilot-operated check valves 901 in the make and break direction protection device 9. The female combination joint 502 on the quick-connect combination assembly 5 is respectively connected to the pilot ports of the two pilot-operated check valves 901 and the oil return port of the hydraulic control system, and the corresponding male combination joints 501 converge at one place and are connected. The quick-connect mechanical interlock protection device 8 and the quick-connect hydraulic interlock protection device 10 provide double protection for the quick-connect combination assembly 5: operating the wrench 503 to connect or separate the female combination joint 502 and the male combination joint 501. When the quick-connect combination assembly 5 is connected, the wrench 503 pulls the flexible shaft 802 to drive the flexible shaft gate valve 805 to reverse, and the hydraulic motor control circuit is in the unloading state. At the same time, the pilot ports of the two pilot-operated check valves 901 in the make and break direction protection device 9 are connected to the oil return port of the hydraulic control system, and the two pilot-operated check valves 901 are closed, cutting off the oil passage leading to the hydraulic motor 3. The hydraulic motor control circuit is in the unloading and locked state, ensuring that the hydraulic motor 3 cannot rotate when the quick-connect combination assembly 5 is connected, avoiding potential safety hazards caused by incorrect operation. When the quick-connect combination assembly 5 is separated, the spring 804 in the quick-connect mechanical interlock protection device 8 pushes the flexible shaft gate valve 805 to return to its original position. At the same time, the pilot ports of the two pilot-operated check valves 901 in the make and break direction protection device 9 are not affected by the quick-connect combination assembly 5, and the hydraulic motor control circuit is in the normal working state.

[0042] As Figure 4 、 6 shown, preferably, a positioning device is provided on the spool of the third manual reversing valve 403. After operating the third manual reversing valve 403, its spool can be positioned at a fixed position.

[0043] As Figure 1 、 2 、4 shown, preferably, the hydraulic boosting device 11 and the flow dividing and pressure maintaining device 7 are integrated into an integral valve group.

[0044] As Figure 7 shown, another implementation of the oil port connection of the gas isolation type accumulator 602 in the pressure relief device 6 is that its oil port is directly connected to the fuel tank to directly release the pressure in the hydraulic clamping cylinder 203.

[0045] As Figure 4As shown, preferably, there is one, two or more hydraulic clamping cylinders 203. When there is one, the oil outlet of the pilot-operated check valve 702 is directly connected to the rodless cavity of the hydraulic clamping cylinder 203. When there are two or more, the number of oil outlets of the flow dividing valve 701 correspondingly is also two or more.

[0046] The specific operation method of this technical solution is as follows:

[0047] Step 1: Clamping the pipe string operation: Push the main clamp of the power tongs to the center of the pipe string, and then operate the wrench 503 to connect the female combination joint 502 with the male combination joint 501. At this time, protected by the double protection of the quick-connect mechanical interlock protection device 8 and the quick-connect hydraulic interlock protection device 10, the hydraulic motor control circuit is in the unloading and locking state; Push the second manual reversing valve 402. After the hydraulic oil is pressurized, it is supplied to the rodless cavities of the two hydraulic clamping cylinders 203 through the flow dividing and pressure maintaining device 7 to drive the hydraulic cylinder clamping type tong head 2 to clamp the pipe string; Operate the second manual reversing valve 402 to return to the middle position. The flow dividing and pressure maintaining device 7 keeps the pressure oil in the rodless cavities of the hydraulic clamping cylinders 203 to maintain the clamping of the pipe string; Then operate the wrench 503 to separate the female combination joint 502 from the male combination joint 501, and the quick-connect mechanical interlock protection device 8 and the quick-connect hydraulic interlock protection device 10 are unlocked simultaneously. At this time, the rotation direction of the hydraulic motor 3 is restricted by the make-up and break-out direction protection device 9. Select the next make-up or break-out operation according to the operation requirements;

[0048] Step 2: Make-up and break-out operation:

[0049] a. Make-up operation: Push the third manual reversing valve 403 to the make-up control direction, and then push the first manual reversing valve 401. The hydraulic motor 3 rotates, and the hydraulic cylinder clamping type tong head 2 clamps the pipe string and rotates in the make-up direction until the make-up torque reaches the set value and stops rotating; Operate the first manual reversing valve 401 to return to the middle position, operate the ball valve 601 to open, unload the pressure oil kept in the rodless cavity of the hydraulic clamping cylinder 203 and then close the ball valve 601, and then pull the first manual reversing valve 401 to make the hydraulic cylinder clamping type tong head 2 rotate in the reverse direction until its opening is centered;

[0050] b. Break-out operation: Pull the third manual reversing valve 403 to the break-out control direction, and then pull the first manual reversing valve 401. The hydraulic motor 3 rotates in the reverse direction, and the hydraulic cylinder clamping type tong head 2 clamps the pipe string and rotates in the break-out direction until the upper and lower pipe strings are separated. Continue to pull the first manual reversing valve 401, and the hydraulic cylinder clamping type tong head 2 continues to rotate until the opening is centered;

[0051] Step 3. Reset operation of the clamping mechanism 202: Finally, operate the wrench 503 to connect the female combined joint 502 with the male combined joint 501, pull the second manual directional control valve 402 to supply oil to the rod chamber of the hydraulic clamping cylinder 203, and the single rod of the hydraulic clamping cylinder 203 retracts, and the clamping mechanism 202 driven by the hydraulic cylinder loosens; operate the second manual directional control valve 402 to return to the middle position, the rodless chamber and the rod chamber of the hydraulic clamping cylinder 203 are both connected to the return oil of the hydraulic control system, and the gas-isolated accumulator 602 discharges the stored hydraulic oil to prepare for the next oil storage; the main tong of the power tong leaves the center of the pipe string, and one make-up or breakout operation ends.

Claims

1. A main clamp hydraulic control system for an open power tong clamped by a hydraulic cylinder, comprising a tong body, a tong head clamped by a hydraulic cylinder, a hydraulic motor, a manual reversing combination valve, a quick-connect combination assembly, a pressure relief device, a flow splitting and pressure maintaining device, a quick-connect mechanical interlock protection device, an up / down torque direction protection device, a quick-connect hydraulic interlock protection device, and a hydraulic boosting device. The tong head clamped by the hydraulic cylinder is arranged at the front of the tong body and comprises a large gear for tong head opening, a clamping mechanism, and a hydraulic clamping cylinder. The hydraulic clamping cylinder drives the clamping mechanism to clamp the pipe string. The hydraulic motor is arranged at the rear of the tong body to transmit power to the large gear for tong head opening. The manual reversing combination valve comprises a first manual reversing valve, a second manual reversing valve, and a third manual reversing valve. The quick-connect combination assembly comprises a male combination joint, a female combination joint, and a wrench. It is characterized in that: The pressure relief device, the flow splitting and pressure maintaining device, the hydraulic boosting device, and the male combination joint are arranged on the tong head clamped by the hydraulic cylinder; the manual reversing combination valve, the quick-connect mechanical interlock protection device, the up / down torque direction protection device, the quick-connect hydraulic interlock protection device, and the female combination joint are arranged on the tong body; The first manual reversing valve is connected to the oil port of the hydraulic motor to form a hydraulic motor control circuit; The second manual reversing valve is connected to the hydraulic clamping cylinder through the quick-connect combination assembly, the flow splitting and pressure maintaining device, and the hydraulic boosting device to form a hydraulic clamping cylinder control circuit. The flow splitting and pressure maintaining device is arranged between one oil port of the second manual reversing valve and the rodless cavity of the hydraulic clamping cylinder and consists of a flow splitting valve and a hydraulic control one-way valve. The hydraulic boosting device is arranged in parallel in the oil circuit between the flow splitting and pressure maintaining device and the male combination joint. One outlet of the male combination joint is connected to the oil inlet of the hydraulic boosting device, and the other outlet is connected to the oil inlet of the hydraulic control one-way valve in the flow splitting and pressure maintaining device. The liquid flow direction of the hydraulic control one-way valve points to the hydraulic clamping cylinder. Its oil outlet is connected to the oil inlet of the flow splitting valve, its hydraulic control port is connected to the male combination joint connecting the other oil port of the second manual reversing valve, the two oil outlets of the flow splitting valve are respectively connected to the rodless cavities of the two hydraulic clamping cylinders, and the oil inlet of the flow splitting valve is simultaneously connected to the oil outlet of the hydraulic boosting device. The other oil port of the second manual reversing valve is connected to the rod end cavity of the hydraulic clamping cylinder through the quick-connect combination assembly; The pressure relief device is arranged in the oil circuit between one oil port of the second manual reversing valve and the rodless cavity of the hydraulic clamping cylinder to form a pressure relief circuit for the rodless cavity of the hydraulic cylinder. The pressure relief device consists of a ball valve and a gas-isolated accumulator. The oil inlet of the ball valve is connected to the oil path between the hydraulic control one-way valve and the flow splitting valve in the flow splitting and pressure maintaining device, and its oil outlet is connected to the oil port of the gas-isolated accumulator and the rod end cavity of the hydraulic clamping cylinder; The quick-connect mechanical interlock protection device comprises a quick-connect combination assembly, a connecting cable, a flexible shaft, a bracket, a spring, and a flexible shaft gate valve. One end of the flexible shaft is connected to the wrench in the quick-connect combination assembly through the connecting cable, and the other end is connected to the flexible shaft gate valve. The bracket is fixed to the flexible shaft gate valve. The spring is arranged in series in the flexible shaft and abuts between the bracket and the flexible shaft gate valve; The make-up and break-out direction protection device includes a third manual reversing valve and two pilot-operated check valves. The third manual reversing valve is included in the manual reversing combination valve. The two pilot-operated check valves are respectively connected in series at the inlet and outlet ports of the hydraulic motor in the hydraulic motor control circuit, and the fluid flow directions of the pilot-operated check valves both point to the hydraulic motor. The two oil ports of the third manual reversing valve are respectively communicated with the pilot ports on the two pilot-operated check valves. The quick-connect hydraulic interlock protection device includes a quick-connect combination assembly and the two pilot-operated check valves in the make-up and break-out direction protection device. The female combination joints on the quick-connect combination assembly are respectively communicated with the pilot ports on the two pilot-operated check valves and the return oil port of the hydraulic control system, and the corresponding male combination joints are converged and connected.

2. The main pliers hydraulic control system of the open type power pliers clamped by a hydraulic cylinder according to claim 1, further characterized in that: The third manual reversing valve in the make-up and break-out direction protection device is arranged in parallel in the hydraulic motor control circuit and forms a secondary control oil circuit for the hydraulic motor with the two pilot-operated check valves.

3. The main pliers hydraulic control system of an open power pliers clamped by a hydraulic cylinder according to claim 1 or 2, characterized in that: A positioning device is provided on the spool of the third manual reversing valve.

4. A master clamp hydraulic control system for an open power clamp clamped by a hydraulic cylinder according to claim 1, characterized in that: The hydraulic boosting device and the flow splitting and pressure maintaining device are integrated into an integral valve group.

5. The main pliers hydraulic control system of the open power pliers clamped by a hydraulic cylinder according to claim 1 or 4, further characterized in that: The oil port of the gas isolation type accumulator in the pressure relief device is directly connected to the oil tank.

6. The main pliers hydraulic control system of an opening power pliers clamped by a hydraulic cylinder according to claim 1, characterized in that: The hydraulic clamping cylinder is one, two or more. When it is one, the outlet port of the pilot-operated check valve is directly communicated with the rodless cavity of the hydraulic clamping cylinder; when it is two or more, the number of outlet ports of its flow splitting valve is correspondingly two or more.

7. The control method of the main tong hydraulic control system of the open type power tong as claimed in claim 1, wherein: Step 1. Clamping pipe string operation: Push the main tong of the power tong to the center of the pipe string, and then operate the wrench to connect the female combination joint with the male combination joint. At this time, under the double protection of the quick-connect mechanical interlock protection device and the quick-connect hydraulic interlock protection device, the hydraulic motor control circuit is in a unloading and locked state; Push the second manual reversing valve. After the hydraulic oil is boosted, it supplies oil to the rodless cavities of the two hydraulic clamping cylinders through the flow splitting and pressure maintaining device, driving the hydraulic cylinder clamping type tong head to clamp the pipe string; Operate the second manual reversing valve to return to the middle position. The flow splitting and pressure maintaining device keeps the pressure oil in the rodless cavities of the hydraulic clamping cylinders to maintain the clamping of the pipe string; Then operate the wrench to separate the female combination joint from the male combination joint. The quick-connect mechanical interlock protection device and the quick-connect hydraulic interlock protection device are unlocked at the same time. At this time, the rotation direction of the hydraulic motor is restricted by the make-up and break-out direction protection device. Select the next make-up or break-out operation according to the operation requirements. Step 2. Make-up and break-out operation: a. Make-up operation: Push the third manual reversing valve to the make-up control direction, and then push the first manual reversing valve. The hydraulic motor rotates, and the hydraulic cylinder clamping type tong head clamps the pipe string and rotates in the make-up direction until the make-up torque reaches the set value and stops rotating; Operate the first manual reversing valve to return to the middle position, operate the ball valve to open, unload the pressure oil kept in the rodless cavity of the hydraulic clamping cylinder and then close the ball valve, and then pull the first manual reversing valve to make the hydraulic cylinder clamping type tong head rotate in the reverse direction until its opening is centered. b. Shackle operation: Pull the third manual directional control valve to the shackle control direction, then pull the first manual directional control valve. The hydraulic motor rotates in the reverse direction, and the clamping type tong head of the hydraulic cylinder clamps the pipe string and rotates along the shackle direction until the upper and lower pipe strings are disengaged. Continue to pull the first manual directional control valve, and the clamping type tong head of the hydraulic cylinder continues to rotate until the opening is centered; Step 3. Clamping mechanism reset operation: Finally, operate the wrench to connect the female combination joint and the male combination joint. Pull the second manual directional control valve to supply oil to the rod chamber of the hydraulic clamping cylinder. The single rod of the hydraulic clamping cylinder retracts, and the clamping mechanism driven by the hydraulic cylinder loosens. Manipulate the second manual directional control valve to return to the neutral position. The rodless chamber and the rod chamber of the hydraulic clamping cylinder are both connected to the return oil of the hydraulic control system. The gas isolation type accumulator discharges the stored hydraulic oil to prepare for the next oil storage. The main tong of the power tong leaves the center of the pipe string, and one make-up or unmake-up operation is completed.

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