Sensor for casing pipe screwing-on measurement

Abstract

The utility model relates to oil field casing drilling, in particular to a sensor for casing screwing-on measurement, and aims to solve the problem that the error correction result is inaccurate due to the temperature difference between the placement position of a temperature sensor and the patch position of a strain gauge and the self measurement error of the temperature sensor. According to the utility model, through the arrangement of the PCB groove, the radio frequency antenna groove and the battery hole, the number of turns of thread rotation in the threaded connection process of casing drilling equipment and the torque generated during thread matching can be monitored at the same time, and the quality of threaded connection between equipment can be ensured more effectively. And the design of a Wheatstone bridge temperature compensation circuit can be completed according to the sensitivity of the negative temperature coefficient of the strain gauge and the resistance change of the positive temperature coefficient. Through the feedback mechanism of the compensation circuit, the reduction of the output voltage of the strain gauge Wheatstone bridge circuit caused by the temperature can be effectively compensated.

Description

Technical Field

[0001] This utility model relates to the field of oilfield casing drilling technology, and in particular to a sensor for measuring casing thread. Background Technology

[0002] Casing drilling technology refers to a drilling method that directly uses casing to replace drill pipe in the drilling process, connecting the downhole drilling tools and utilizing the casing to transmit torque, pressure, and hydraulic pressure. This technology offers significant advantages for the oil industry, reducing construction time and costs. However, the torsional capacity of the threads used in casing drilling is one of the key factors restricting its development, and the correct connection of the casing threaded joints is crucial for the successful execution of casing drilling. Effectively ensuring the number of turns and tightness of the threads during casing connection is essential for the safety, maneuverability, and long-term correct operation of the equipment. Therefore, to meet the trend of precision control and intelligent development in drilling technology, precise thread torque and turn count measurement devices are a prerequisite for the application of new drilling technologies in the market. Furthermore, the oil extraction field involves complex operating conditions, and most extraction environments face extreme weather conditions such as high temperatures or extreme cold. Traditional torque measurement methods using Wheatstone bridge integrated systems cannot avoid the influence of temperature on strain gauge sensitivity; therefore, temperature compensation is necessary in practical applications. The commonly used solution is to add a temperature sensor near the strain gauge, which collects ambient temperature signals in real time and then uses algorithms on a host computer to correct for sensor acquisition errors. However, this strategy has a significant drawback: there is a temperature difference between the temperature sensor's location and the strain gauge's application location, and the temperature sensor's own measurement errors can also lead to inaccurate error correction results. Therefore, a better approach to temperature compensation for the sensor is to compensate for its temperature error through hardware circuit design. Utility Model Content

[0003] The purpose of this invention is to provide a sensor for measuring the buckle on a sleeve, so as to solve the problems of temperature difference between the temperature sensor placement position and the strain gauge patch position, as well as the inaccurate error correction results caused by the temperature sensor's own measurement error.

[0004] This utility model provides a sensor for measuring the buckle on a sleeve, including a strain shaft, the strain shaft body being fitted with an explosion-proof housing, the two ends of the strain shaft extending out of the explosion-proof housing having connecting threads, and the explosion-proof housing containing a power module, a signal acquisition module, a wireless transceiver module, and a control module;

[0005] There is a ring-shaped space between the strain shaft and the explosion-proof housing. The strain shaft is fitted with strain gauges that form a Wheatstone bridge and are located within this ring-shaped space.

[0006] The signal acquisition module includes a Wheatstone bridge temperature compensation circuit for strain signal acquisition and temperature compensation.

[0007] Furthermore, the strain gauges of the Wheatstone bridge are evenly distributed on the 360° strain axis at an angle of 45° to the central axis of the strain axis, and are alternately arranged with the baseline of the strain axis at angles of 45° and 135°.

[0008] Furthermore, the strain shaft body is provided with an annular groove surface, which together with the inner wall of the explosion-proof housing forms the annular space;

[0009] The explosion-proof housing is axially limited on both sides by the cooperation of the shoulders on the strain shaft and the flange.

[0010] Furthermore, the explosion-proof housing is symmetrically provided with two sets of embedded measurement system channels, each set of channels including a connected PCB slot, an RF antenna slot and a battery hole;

[0011] The PCB slot is connected to the battery hole through a through hole and leads out battery wires, and is connected to the RF antenna slot through another through hole to connect signal lines;

[0012] The PCB slot and the RF antenna slot are respectively provided with a top cover and an antenna cover.

[0013] The battery is placed inside the battery hole to form the power module, the wireless antenna is placed inside the radio frequency antenna slot to form the wireless transceiver module, and the microcontroller is placed inside the PCB slot to form the control module.

[0014] Furthermore, the battery compartment is equipped with a battery box and a battery box cover with a pull ring. The bottom of the battery box has an upper battery box plate and a lower battery box plate. The pull ring is hinged in a groove at the end of the battery box cover to facilitate unfolding and folding.

[0015] The battery box has a through hole at the bottom, and the upper bottom plate and the lower bottom plate of the battery box are sequentially assembled at both ends of the through hole at the bottom of the battery box.

[0016] The battery opening is provided with a battery cover. A buckle is provided through the outward protruding section of the battery cover. The folded surface of the buckle abuts against the axial end face of the explosion-proof shell to prevent the battery box from rotating. A through hole is provided laterally on the outward protruding section of the battery cover. A cotter pin is inserted into the through hole. A gasket is provided on the battery box. The gasket is located inside the cotter pin. A cord loop is provided on the outward side of the battery cover.

[0017] Furthermore, a flange is fitted onto the strain shaft, and a plurality of first positioning grooves are provided on the side of the flange facing the explosion-proof housing. The explosion-proof housing is provided with a second positioning groove corresponding to the first positioning groove. A positioning pin is movably provided in the space formed by the first positioning groove and the second positioning groove. The groove wall of the first positioning groove is provided with an outwardly extending positioning hole. A fastening screw for tightening the positioning pin is fitted in the positioning hole. The strain shaft is provided with a circular groove corresponding to the radial end of the positioning pin.

[0018] Fixing holes are provided on both sides of the first positioning groove, and connecting bolts for connecting with the explosion-proof shell are fitted in the fixing holes.

[0019] Furthermore, the explosion-proof housing is symmetrically provided with two grooves on its outer periphery, and a battery hole extending in the same direction and a through hole for connecting to the PCB slot are provided on one side wall of the groove.

[0020] The other side wall of the groove is provided with a machining hole for passing through the radio frequency antenna slot. The distal section of the machining hole forms a through hole for connecting the PCB slot, and the opening end of the machining hole is provided with a large threaded cap.

[0021] Furthermore, the signal acquisition module integrates a three-axis gyroscope for acquiring the number of turns of the thread;

[0022] The signal acquisition module also includes an A / D conversion circuit and a temperature sensor; these are used for analog-to-digital conversion of Wheatstone bridge signals and for real-time temperature measurement and alarm of the working area, respectively.

[0023] Furthermore, the Wheatstone bridge temperature compensation circuit includes: differential operational amplifiers A1, A2, A3, pull-up resistors R1, R2, R3, R8, strain gauges Ra, Rb, Rc, Rd, and resistors R6, R7, R4, R5, R9, R10, R11, R13.

[0024] One end of the pull-up resistor R2 is connected to the power supply, and the other end is connected to the non-inverting input of the differential operational amplifier A1; one end of the pull-up resistor R3 is connected to the non-inverting input of the differential operational amplifier A1, and the other end is grounded; one end of the pull-up resistor R1 is connected to the inverting input of the differential operational amplifier A1, one end of the strain gauge Rb, and one end of the strain gauge Rd, and the other end is grounded.

[0025] One end of resistor R6 is connected to the power supply, and the other end is connected to the non-inverting input of differential operational amplifier A2; one end of resistor R7 is connected to the power supply, and the other end is grounded; one end of resistor R4 is connected to the output of differential operational amplifier A1, and the other end is connected to the inverting input of differential operational amplifier A2; one end of pull-up resistor R8 is connected to the output of differential operational amplifier A2, and the other end is connected to pull-up resistor R1; one end of resistor R5 is connected to resistor R4, and the other end is connected to resistor R8.

[0026] One end of the strain gauge Ra is connected to the output terminal of the differential operational amplifier A1, and the other end is connected to the strain gauge Rb and the resistor R13; one end of the strain gauge Rc is connected to the output terminal of the differential operational amplifier A1, and the other end is connected to the strain gauge Rd and the resistor R9; the non-inverting input terminal of the differential operational amplifier A3 is connected to the resistor R9, the inverting input terminal is connected to the resistor R13, and one end of the resistor R10 is connected to the resistor R13, and the other end is connected to the output terminal of the differential operational amplifier A3.

[0027] This utility model has at least the following beneficial effects:

[0028] This invention proposes a sensor for measuring thread engagement on casing, which is economically effective and meets the needs of special working conditions. The solution comprises an embedded measurement system channel consisting of a PCB slot, an RF antenna slot, and a battery hole. This means the solution includes two identical embedded measurement system channels, capable of simultaneously monitoring the number of thread rotations and the torque generated during thread engagement in casing drilling equipment, thus more effectively ensuring the quality of threaded connections between equipment. Furthermore, the accuracy of the current thread engagement count and torque measurement can be determined by the difference between the measurement results of the two channels, and channel switching can be completed via program commands, further improving the equipment's endurance. It also features wireless transceiver functionality, enabling long-distance wireless transmission of data and commands, thus protecting the personal safety of operators to a certain extent. Moreover, temperature compensation for strain gauge signals is implemented through hardware circuitry, further improving the accuracy of torque acquisition signals. This is of great significance in the application of collecting thread engagement counts and thread tightening torque between oil drilling casings.

[0029] This invention proposes a sensor for measuring thread engagement on bushings. This sensor can determine the accuracy of the current number of thread turns and thread connection torque measurement by comparing the results of two measurements. Furthermore, it can perform wake-up, sleep, and switching functions between channels via program commands, further improving the device's endurance. Moreover, this invention provides a sensor for measuring thread engagement on bushings that incorporates the sensitivity of the strain gauge's negative temperature coefficient and the resistance change based on the positive temperature coefficient. Through the feedback mechanism of the compensation circuit, it can effectively compensate for the decrease in the output voltage of the strain gauge Wheatstone bridge caused by temperature.

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the mechanical structure of a sensor for measuring the buckle on a sleeve according to the present invention;

[0032] Figure 2 This is a system structure block diagram of a sensor for measuring the buckle on a sleeve according to the present invention;

[0033] Figure 3 This is a schematic diagram of a Wheatstone full-bridge circuit.

[0034] Figure 4 The mounting position of a single Wheatstone full-bridge circuit strain gauge on the strain axis;

[0035] Figure 5 This is a schematic diagram of a Wheatstone bridge temperature compensation circuit.

[0036] Figure 6 This is a top view of a sensor for measuring the threaded connection on a sleeve according to the present invention;

[0037] Figure 7 This is a top cross-sectional view of the explosion-proof housing of this utility model;

[0038] Figure 8 This is a bottom view of the flange of a sensor for measuring the threaded connection on a sleeve according to the present invention.

[0039] Figure 9 This is a flange side view of a sensor for measuring the threaded connection on a sleeve according to the present invention.

[0040] Figure 10 This is a structural diagram of the strain shaft of this utility model;

[0041] Figure 11 This is a half-sectional left view of a sensor for measuring the buckle on a sleeve according to the present invention;

[0042] Figure 12This is a bottom view of the explosion-proof housing of this utility model.

[0043] In the diagram: 1. Strain axis; 2. Explosion-proof housing; 3. Top cover; 300. Circular groove; 4. Antenna cover; 5. Battery cover; 6. Rope buckle ring; 7. Cotter pin; 8. Gasket; 9. Buckle; 10. Battery box cover; 11. Pull ring; 12. Battery box; 13. Upper base plate of battery box; 14. Lower base plate of battery box; 15. Small threaded cover; 16. Antenna frame; 17. Antenna frame plate; 18. Antenna cap; 19. Connecting bolt; 20. Flange; 200. Threaded groove; 201. Fixing hole; 202. First positioning groove; 203. Positioning hole; 204. Second positioning groove; 21. Positioning pin; 22. Fastening screw; 23. Large threaded cover; 24. PCB slot; 25. RF antenna slot; 26. Battery hole; a. Groove. Detailed Implementation

[0044] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0045] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0046] Combination Figures 1-12 This embodiment is described below.

[0047] This embodiment is a sensor for measuring the buckle on a sleeve, including a strain shaft 1, the strain shaft 1 is fitted with an explosion-proof housing 2, the two ends of the strain shaft 1 extending out of the explosion-proof housing 2 have connecting threads, and the explosion-proof housing 2 is provided with a power module, a signal acquisition module, a wireless transceiver module and a control module.

[0048] There is a ring-shaped space between the strain shaft 1 and the explosion-proof housing 2. The strain gauges that make up a Wheatstone bridge are attached to the shaft of the strain shaft 1 and are located in the ring space. A small hole facing the ring space is provided in the PCB slot. The microcontroller in the PCB slot is connected to the strain gauge signal line through this small hole.

[0049] The signal acquisition module includes a Wheatstone bridge temperature compensation circuit for strain signal acquisition and temperature compensation.

[0050] In this embodiment, the power module includes a lithium battery, a voltage conversion module, and a battery management chip. The voltage conversion module is used to convert the voltage output by the lithium battery. The lithium battery consists of two 3.6V cells, which together output a 7.2V power supply voltage. The voltage conversion module can convert the 7.2V power supply voltage to 3.3V and the 7.2V power supply voltage to 5V, thereby providing power to the various modules in the system.

[0051] During use, the voltage / current status of the power supply battery can be monitored in real time through the battery management chip. The microcontroller can directly access the data register in the battery management chip through the I2C bus to obtain the current battery power and discharge status.

[0052] In this embodiment, the wireless transceiver module uses LoRa wireless spread spectrum communication technology for data transmission. The RF antenna employs an impedance design, utilizing high-frequency inductors and capacitors to achieve an LC oscillation circuit, thereby maximizing the transmission of signal power from the source to the load. The built-in RF antenna is fixed by a bracket inside the RF antenna slot 13 of the explosion-proof housing 2. The microcontroller transmits the packaged data to the host computer via LoRa wireless spread spectrum communication technology, while simultaneously receiving register addressing commands, Flash memory read / clear commands, and low-power mode entry / wake-up commands from the host computer. LoRa wireless spread spectrum communication technology offers a longer transmission distance and encryption, resulting in higher reliability and security of the collected data during wireless signal transmission.

[0053] This invention proposes a sensor for measuring thread engagement on casing, which is economically effective and meets the needs of special working conditions. The solution comprises a PCB slot 12, an RF antenna slot 13, and a battery hole 14, forming an embedded measurement system channel. This means the solution includes two identical embedded measurement system channels, capable of simultaneously monitoring the number of thread rotations and the torque generated during thread engagement in casing drilling equipment, thus more effectively ensuring the quality of threaded connections between equipment. Furthermore, the accuracy of the current thread engagement count and torque measurement can be determined by the difference between the measurement results of the two channels, and channel switching can be completed via program commands, further improving the equipment's endurance. It also features wireless transceiver functionality, enabling long-distance wireless transmission of data and commands, thus protecting the personal safety of operators to a certain extent. Moreover, temperature compensation for strain gauge signals is implemented through hardware circuitry, further improving the accuracy of torque acquisition signals. This is of great significance in the application of collecting thread engagement counts and thread tightening torque between oil drilling casings.

[0054] This invention proposes a sensor for measuring thread engagement on sleeves. This sensor can determine the accuracy of the current number of thread turns and thread connection torque measurement by comparing the results of two measurements. It can also perform wake-up, sleep, and switching functions between channels via program commands, further improving the equipment's endurance. Furthermore, this invention provides a sensor for measuring thread engagement on sleeves that incorporates the sensitivity of the strain gauge's negative temperature coefficient and the resistance change of its positive temperature coefficient, designing a Wheatstone bridge temperature compensation circuit. Through the feedback mechanism of the compensation circuit, it can effectively compensate for the decrease in the output voltage of the strain gauge Wheatstone bridge circuit caused by temperature. In addition, this invention provides a sensor for measuring thread engagement on sleeves that has wireless transceiver capabilities, enabling long-distance wireless transmission of data and commands, thus protecting the personal safety of operators to a certain extent.

[0055] Furthermore, the strain gauges of the Wheatstone bridge are evenly distributed on the 360° axis of the strain axis 1 at an angle of 45° to the central axis of the strain axis 1, and are alternately arranged with the baseline of the strain axis 1 at angles of 45° and 135°.

[0056] In this embodiment, eight strain gauges are attached to the annular surface at the assembly point of the strain shaft 1 and the explosion-proof housing 2. The eight strain gauges are evenly distributed on the 360° annular surface at an angle of 45°, and are arranged alternately with the baseline of the strain shaft 1 at angles of 45° and 135°, together forming two sets of Wheatstone full-bridge circuits.

[0057] Furthermore, the strain shaft 1 has an annular groove surface on its shaft body, which forms an annular space with the inner wall of the explosion-proof housing 2;

[0058] The explosion-proof housing 2 is axially limited on both sides by the shoulders on the strain shaft 1 and the flange 20.

[0059] In this embodiment, the strain shaft 1 is made of high-strength, high-toughness 40CrNiMo or 40CrNi2MoA alloy. Both ends are designed with tapered external threads and tapered internal threads, respectively, enabling threaded assembly with external casing drilling equipment. This effectively transmits the torque applied by the drilling equipment and generates deformation. The explosion-proof housing 2 is made of non-magnetic alloy P550 to avoid shielding and absorption of radio electromagnetic wave signals transmitted within the antenna slot by magnetic materials. The explosion-proof housing 2 is mounted on the shoulder of the strain shaft 1, with a flange 20 located below. The shoulder of the strain shaft 1 and the flange 20 fix the explosion-proof housing 2 vertically, thereby limiting its axial movement along the strain shaft 1.

[0060] Furthermore, the explosion-proof housing 2 is symmetrically provided with two sets of embedded measurement system channels, each set of channels including a connected PCB slot 24, an RF antenna slot 25 and a battery hole 26;

[0061] The PCB slot 24 is connected to the battery hole 26 through a through hole and leads out a battery wire, and is connected to the RF antenna slot 25 through another through hole to connect a signal line;

[0062] The PCB slot 24 and the RF antenna slot 25 are respectively provided with a top cover 3 and an antenna cover 4.

[0063] The battery is placed in the battery hole 26 to form the power module, the wireless antenna is placed in the radio frequency antenna slot 25 to form the wireless transceiver module, and the microcontroller is placed in the PCB slot 24 to form the control module.

[0064] The explosion-proof housing 2 is provided with a large threaded cover 23, which is used to seal the guide hole between the PCB slot 24 and the radio frequency antenna slot 25.

[0065] In this embodiment, an antenna frame 16 is provided in the radio frequency antenna slot 25, an antenna frame plate 17 is provided at the shoulder of the antenna frame 16, an antenna cap 18 is provided on the antenna frame plate 17, and a small threaded cover 15 is provided on the explosion-proof shell 2 to achieve the sealing of the auxiliary guide hole in the antenna slot area.

[0066] The explosion-proof housing 2 has a centrally symmetrical structure. Inside the housing 2, two PCB slots 12, two RF antenna slots 13, and two battery holes 14 are arranged symmetrically in a circular pattern. The PCB slots 12, RF antenna slots 13, and battery holes 14 are used to mount hardware circuit boards, a wireless transceiver module with an RF antenna, and a power battery, respectively. The PCB slots 12, RF antenna slots 13, and battery holes 14 are interconnected through power line through-holes inside the explosion-proof housing 2, enabling the connection of signal and power lines within the embedded system. In this solution, one PCB slot 12, one RF antenna slot 13, and one battery hole 14 constitute one embedded measurement system channel. This means that the solution includes two identical embedded measurement system channels, which can simultaneously monitor the number of thread rotations and the torque generated during thread engagement in the casing drilling equipment's threaded connection, more effectively ensuring the quality of the threaded connection between devices. Furthermore, the accuracy of the current thread count and thread connection torque measurement can be determined by the difference in measurement results between the two channels, and channel switching can be completed through program commands, further improving the equipment's endurance.

[0067] In this embodiment, the microcontroller consists of a microcontroller, a crystal oscillator circuit, a reset circuit, and a program download interface. The microcontroller uses an STM32G474 chip for data processing, storage, and packaging. In this embodiment, the microcontroller also provides a choice between two modes: a working mode and a low-power shutdown mode. The crystal oscillator circuit includes a 48MHz external passive crystal oscillator and a 16MHz internal passive crystal oscillator, along with appropriate capacitors and resistors to maintain the normal operation of the microcontroller. The reset circuit includes a window watchdog timer for verifying the entire embedded system program and performing power-down reset of the microcontroller. Enabling the window watchdog timer through the microcontroller's GPIO port enables the verification of the entire embedded system program and the power-down reset function. The program download interface is an external 4×1 program download interface driven by ST-Link, with multiple download interfaces connected to the microcontroller's SWCLK, SWDIO, VCC, and GND pins respectively.

[0068] Furthermore, the battery hole 26 is provided with a battery compartment 12 and a battery compartment cover 10 with a pull ring 11. The bottom of the battery compartment 12 is provided with an upper battery compartment plate 13 and a lower battery compartment plate 14. The pull ring 11 is hinged in a groove at the end of the battery compartment cover 10 to facilitate unfolding and folding.

[0069] The battery box 12 has a through hole at the bottom, and the upper bottom plate 13 and the lower bottom plate 14 of the battery box are sequentially assembled at both ends of the through hole at the bottom of the battery box 12.

[0070] The battery hole 26 has an opening with a battery cover 5. A buckle 9 is inserted through the outward protruding section of the battery cover 5. The folded surface of the buckle 9 abuts against the axial end face of the explosion-proof shell 2 to prevent the battery box 12 from rotating. A through hole is provided laterally on the outward protruding section of the battery cover 5. A cotter pin 7 is inserted into the through hole. A gasket 8 is fitted on the battery box 12. The gasket 8 is located inside the cotter pin 7. A cord loop 6 is provided on the outward side of the battery cover 5.

[0071] In this embodiment, a battery box 12 and a battery box cover 10 with a pull ring 11 are provided inside the battery hole 26. The battery box cover 10 and the battery box 12 are assembled by threads. The battery box 12 is made of polytetrafluoroethylene with good insulation properties, and the battery box cover 10 is made of CuNi10Fe with good conductivity properties. The bottom of the battery box 12 has a stepped through hole with a small diameter in the middle and larger diameters on both sides. The upper bottom plate 13 and the lower bottom plate 14 of the battery box are sequentially assembled at both ends of the through hole at the bottom of the battery box 12. The upper bottom plate 13 and the lower bottom plate 14 of the battery box have threaded through holes in their centers. By inserting screws into these threaded through holes, the upper bottom plate 13 and the lower bottom plate 14 of the battery box can be installed and fixed to the battery box 14. The pull ring 11 is installed in the groove of the battery box cover 10. When replacing the battery, the pull ring 11 can be pulled out by hand, and the battery box cover 10 and the battery box 12 can be disassembled by twisting the pull ring 11. The battery cover 5 is threadedly connected to the explosion-proof housing 2, enabling the encapsulation of the battery area and the return flow of the negative electrode. The battery cover 5 is made of CuNi10Fe, a material with good conductivity. A buckle 9 is inserted through the outward protruding section of the battery box 12. The folded surface of the buckle 9 abuts against the axial end face of the explosion-proof housing 2 to prevent rotation of the battery box 12. The buckle 9 and the battery cover 5 are coplanar, and a gasket 8 ensures a tight fit between them. A cotter pin 7 is inserted into the transversely arranged through hole in the outward protruding section of the battery cover 5, applying a pre-tightening force to the gasket 8, thus acting as a clamp and ensuring a tight fit between the buckle 9 and the battery box 5. The folded surface of the buckle 9 self-locks with the end face of the explosion-proof housing 2 to prevent rotation of the battery box 5 and ensure threaded assembly with the explosion-proof housing 2. A threaded hole is opened in the outward protruding section of the battery cover 5. A screw is inserted into the threaded hole to assemble the rope buckle 6 with the battery cover 5.

[0072] Furthermore, a flange 20 is fitted onto the strain shaft 1. The flange 20 has a plurality of first positioning grooves 202 on the side facing the explosion-proof housing 2. The explosion-proof housing 2 has a second positioning groove 204 corresponding to the first positioning grooves 202. A positioning pin 21 is movably arranged in the space formed by the first positioning grooves 202 and the second positioning grooves 204. The groove wall of the first positioning groove 202 has an outwardly extending positioning hole 203. A fastening screw 22 for tightening the positioning pin 21 is fitted in the positioning hole 203. The strain shaft 1 has a circular groove 300 corresponding to the radial end of the positioning pin 21.

[0073] Fixing holes 201 are provided on both sides of the first positioning groove 202, and connecting bolts 19 for connecting with the explosion-proof shell 2 are fitted in the fixing holes 201.

[0074] The flange 20 has a centrally symmetrical layout with eight fixing holes 201 at its ends. Connecting bolts 19 pass through these fixing holes 201 and connect with eight corresponding threaded grooves 200 on the explosion-proof housing 2 to achieve radial fixation of the flange 20. A locating pin 21 is movably installed within the space formed by the first locating groove 202 and the second locating groove 204. It is threaded onto the flange 20 by fastening screws 22, applying a preload to the locating pin 21 so that it inserts into the circular groove 300 on the strain shaft 1, thus fixing the explosion-proof housing 2 onto the strain shaft 1.

[0075] Furthermore, the explosion-proof housing 2 is symmetrically provided with two grooves a on its outer periphery, and a battery hole 26 extending in the same direction and a through hole for connecting the PCB slot 24 are provided on one side wall of the groove a.

[0076] The other side wall of the groove a is provided with a machining hole for passing through the radio frequency antenna groove 25. The distal section of the machining hole forms a through hole for connecting the PCB groove 24. The opening end of the machining hole is provided with a large threaded cap 23.

[0077] The groove a facilitates machining along the chord direction of the explosion-proof housing 2. During machining, the groove a provides clearance, such as when drilling or turning the battery hole, preventing the drill bit from interfering with the explosion-proof housing 2. It also facilitates the machining of through holes, reducing the number of process holes machined on the outer wall of the PCB groove 24 on the explosion-proof housing 2. This improves the strength and sealing of the explosion-proof housing 2 at that location and reduces the need for sealing process holes. The principle behind the machining holes is the same, which facilitates machining, improves the strength and sealing of the PCB groove 24, and prevents the components located within the side wall of the groove a (such as cotter pins and covers) from interfering with the outside environment, thereby increasing the service life of the components during operation.

[0078] Furthermore, the signal acquisition module also includes a three-axis gyroscope, which uses an ADXRS453 angular velocity sensor and is packaged in SOIC_CAV, and is used to acquire the number of turns of the thread.

[0079] During the thread assembly of casing drilling equipment, a three-axis gyroscope is used to collect the acceleration of the equipment turning on the thread in real time. The Kalman filter algorithm and attitude fusion algorithm are used to convert the acceleration into the number of rotations, thereby realizing the acquisition of the number of turns of the thread.

[0080] In this embodiment, the gyroscope selected is the ADXRS453 angular velocity sensor. This sensor employs a differential quad-sensor design, capable of detecting angular velocities up to ±300° / s, while effectively avoiding the influence of linear acceleration. This allows it to provide high-precision sensing signals in harsh environments with shocks and vibrations. Furthermore, the ADXRS453 angular velocity sensor is packaged in SOIC_CAV, enabling it to acquire only the z-axis (yaw angle) angular velocity value, avoiding interference from signals acquired from the x-axis (pitch angle) and y-axis (roll angle).

[0081] Furthermore, the signal acquisition module also includes an A / D conversion circuit and a temperature sensor, which are used for analog-to-digital conversion of Wheatstone bridge signals and real-time temperature measurement and alarm of the working area, respectively.

[0082] The A / D conversion circuit includes a 24-bit AD conversion module, which converts the amplified analog voltage signal into a digital signal and transmits the converted data to the microcontroller via the SPI bus.

[0083] The temperature sensor uses a DS18B9 temperature sensor to collect the temperature signal of the working area in real time. The temperature sensor transmits the collected temperature data to the microcontroller via a single-bus communication protocol. Through temperature sensor settings, alarms can also be triggered when the circuit board is short-circuited or the ambient or CPU temperature is too high.

[0084] Furthermore, the Wheatstone bridge temperature compensation circuit includes: differential operational amplifiers A1, A2, A3, pull-up resistors R1, R2, R3, R8, strain gauges Ra, Rb, Rc, Rd, and resistors R6, R7, R4, R5, R9, R10, R11, R13.

[0085] One end of the pull-up resistor R2 is connected to the power supply, and the other end is connected to the non-inverting input of the differential operational amplifier A1; one end of the pull-up resistor R3 is connected to the non-inverting input of the differential operational amplifier A1, and the other end is grounded; one end of the pull-up resistor R1 is connected to the inverting input of the differential operational amplifier A1, one end of the strain gauge Rb, and one end of the strain gauge Rd, and the other end is grounded.

[0086] One end of resistor R6 is connected to the power supply, and the other end is connected to the non-inverting input of differential operational amplifier A2; one end of resistor R7 is connected to the power supply, and the other end is grounded; one end of resistor R4 is connected to the output of differential operational amplifier A1, and the other end is connected to the inverting input of differential operational amplifier A2; one end of pull-up resistor R8 is connected to the output of differential operational amplifier A2, and the other end is connected to pull-up resistor R1; one end of resistor R5 is connected to resistor R4, and the other end is connected to resistor R8.

[0087] One end of the strain gauge Ra is connected to the output terminal of the differential operational amplifier A1, and the other end is connected to the strain gauge Rb and the resistor R13; one end of the strain gauge Rc is connected to the output terminal of the differential operational amplifier A1, and the other end is connected to the strain gauge Rd and the resistor R9; the non-inverting input terminal of the differential operational amplifier A3 is connected to the resistor R9, the inverting input terminal is connected to the resistor R13, and one end of the resistor R10 is connected to the resistor R13, and the other end is connected to the output terminal of the differential operational amplifier A3.

[0088] This invention proposes a sensor for measuring thread tightening on sleeves. Internally, it employs a Wheatstone bridge temperature compensation circuit consisting of three differential operational amplifiers and adapter resistors. Through the feedback mechanism of the compensation circuit, it can effectively compensate for the strain gauge acquisition error caused by temperature, thereby improving the sensor's accuracy in acquiring thread tightening torque.

[0089] In this embodiment, eight strain gauges are uniformly bonded to the annular surface of strain shaft 1 at 45° intervals using polyacrylic acid resin. They are also alternately arranged with the baseline of strain shaft 1 at 45° and 135° angles, forming two sets of Wheatstone full-bridge circuits. When strain shaft 1 is subjected to torque, shear strain will occur along the 45° and 135° spiral directions, causing the strain gauges along the same bonding direction to experience the same minute strain, resulting in a change in resistivity.

[0090] like Figure 4 As shown, the strain gauge can be regarded as a force-sensitive resistor with an initial resistance of R. For a single Wheatstone full-bridge circuit composed of four strain gauges Ra, Rb, Rc and Rd, by providing the working voltage Ui to this bridge and acquiring the differential signal between the bridge arms, i.e. the potential difference U0, the voltage output signal corresponding to pure shear deformation under torque can be obtained.

[0091] like Figure 5 As shown, the placement of the four strain gauges on the torque axis should satisfy the placement angles shown in the figure. Strain gauges Ra and Rb on one side of the bridge arm and strain gauges Rc and Rd on the other side of the bridge arm form a parallel circuit, and the placement orientation of strain gauges Ra and Rd should be in the principal direction of the normal torque stress.

[0092] For a Wheatstone full-bridge circuit, when a torque is applied and the strain gauge resistance changes, the output voltage Uo can be obtained by measuring the difference between the potentials of the bridge arm points. Neglecting second-order minor quantities, we have:

[0093] (1)

[0094] For an equal-arm Wheatstone bridge composed of identical strain gauges, Ra = Rb = Rc = Rd = R, and the absolute values ​​of the resistance changes are equal under the same strain.

[0095] (2)

[0096] Among them, U o For the acquired full-bridge differential signal, U i Let be the power supply input voltage, k be the sensitivity factor of the strain gauge, and ε be the strain of the strain gauge. For strain axis 1 of the through hole, its polar moment of inertia... It should be:

[0097] (3)

[0098] Among them, R L Let r be the outer diameter of strain shaft 1. L Let be the diameter of the central hole of strain shaft 1. Then, the shear stress generated under the applied torque T... The size is:

[0099] (4)

[0100] Where Ip is the polar moment of inertia of the cross section of strain axis 1, and since strain axis 1 is in pure shear strain, the magnitude of the strain of strain axis 1 in the principal stress direction is:

[0101] (5)

[0102] Where ε is the strain under torque, τ is the magnitude of the shear stress on the outermost surface under torque, v is Poisson's ratio, and Ep is the Young's modulus of strain axis 1. Therefore, the relationship between strain ε and torque T is obtained as follows:

[0103] (6)

[0104] Where G is the shear modulus of strain axis 1, which is related to Poisson's ratio and Young's modulus. Therefore, the final relationship between the torque T and the differential voltage signal U0 is:

[0105] (7)

[0106] From the positive temperature characteristic of the strain gauge resistance and the negative temperature characteristic of the sensitivity, it can be seen that the total resistance of the bridge circuit increases with increasing temperature, while the sensitivity decreases with increasing temperature. Therefore, from equation (2), the differential output voltage U between the bridge arms can be determined. o The temperature decreases, causing the sensor's measured value to be smaller than the actual value, resulting in measurement error. Therefore, temperature compensation is necessary.

[0107] like Figure 6As shown, the Wheatstone bridge temperature compensation circuit consists of a constant current source circuit, a constant current source temperature compensation circuit, a differential amplifier circuit at the bridge output, and a strain acquisition circuit. The constant current source circuit is composed of differential operational amplifier A1 and surrounding adapter resistors; the constant current source temperature compensation circuit is composed of differential operational amplifier A2 and surrounding adapter resistors; the differential amplifier circuit at the bridge output is composed of differential operational amplifier A3 and surrounding adapter resistors; differential operational amplifier A1, bridge resistors R1, R2, and R3, and the Wheatstone full-bridge circuit constitute the strain acquisition circuit for constant current source excitation. Because the total resistance of the bridge increases, the output voltage Vs of the constant current source composed of differential operational amplifier A1 increases. This reduces the inverted output voltage Vt of differential operational amplifier A2, thus reducing the current across the feedback pull-up resistor R8. This feedback to the Wheatstone bridge increases the bridge current, resulting in a decrease in the differential output voltage U between the bridge arms. o The increase achieved the output voltage U of the entire Wheatstone bridge. o After temperature compensation, the measured voltage can be read after passing through differential operational amplifier A3.

[0108] A2 is a differential operational amplifier with the inverting input. According to the basic differential operational amplifier circuit, the output voltage is:

[0109] (8)

[0110] When the amplifier gain resistance ratio When it is time, we can obtain:

[0111] (9)

[0112] The constant current source consisting of differential operational amplifier A1 and its surrounding adapter resistors indicates that:

[0113] (10)

[0114] Where R is the total resistance of the Wheatstone bridge, substituting equation (9) into equation (10) gives:

[0115] (11)

[0116] Further releases:

[0117] (12)

[0118] When strain occurs and a voltage difference is generated at the bridge arm end, combining equations (2) and (12), we can know that:

[0119] (13)

[0120] In equation (13), since the Wheatstone bridge resistance R has a positive temperature coefficient and the sensing sensitivity ΔR has a negative temperature coefficient, the denominator is... It has a negative temperature coefficient. According to expression (2), by rationally designing the temperature compensation circuit and selecting the differential operational amplifier gain-to-resistance ratio i and the feedback pull-up resistor R8, the resistance of the Wheatstone bridge caused by temperature and the effect of the positive / negative temperature coefficient on the output voltage U can be offset. o This achieves the purpose of temperature compensation by mitigating the impact of temperature fluctuations.

[0121] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Terms such as "first," "second," etc., are used to denote names and do not indicate any specific order. The present invention and its embodiments have been described above illustratively, and this description is not restrictive. The present invention can be implemented in other specific forms without departing from its spirit or essential characteristics. The accompanying drawings are only one embodiment of the present invention, and the actual structure is not limited thereto. Any reference numerals in the claims should not limit the scope of the claims. Therefore, if a person skilled in the art, inspired by this description, designs a similar structure and embodiment without departing from the spirit of the invention, such design should fall within the scope of protection of this application.

Claims

1. A sensor for casing makeup measurement, characterized in that, a strain shaft (1) is sleeved with an explosion-proof shell (2), the strain shaft (1) has connecting threads at both ends of the explosion-proof shell (2), and the explosion-proof shell (2) is internally provided with a power module, a signal acquisition module, a wireless transceiver module and a control module; the strain shaft (1) and the explosion-proof shell (2) have a ring-shaped space, the strain shaft (1) is provided with strain gauges constituting a Wheatstone bridge on the shaft body and located in the ring-shaped space, wherein the signal acquisition module comprises a Wheatstone bridge temperature compensation circuit for strain signal acquisition and temperature compensation.

2. A sensor for making up measurements on a casing, according to claim 1, characterized in that, The strain gauges of the Wheatstone bridge are uniformly distributed on the 360° shaft body of the strain shaft (1) at an angle of 45° with the central axis of the strain shaft (1), and are alternately arranged at an angle of 45° and 135° with the axial baseline of the strain shaft (1).

3. The sensor for casing makeup measurement according to claim 1, characterized in that, the shaft body of the strain shaft (1) is provided with an annular recess surface, and the annular recess surface and the inner wall of the explosion-proof shell (2) form the ring-shaped space; the explosion-proof shell (2) is axially limited by the shaft shoulder on the strain shaft (1) and the flange (20) on both sides.

4. The sensor for casing makeup measurement according to claim 3, characterized in that, the explosion-proof shell (2) is symmetrically provided with two groups of embedded measurement system channels, each group of channels comprising a communicating PCB slot (24), a radio frequency antenna slot (25) and a battery hole (26); the PCB slot (24) is in communication with the battery hole (26) through a through hole and leads out the battery lead, and is in communication with the radio frequency antenna slot (25) through another through hole and leads out the signal line; the PCB slot (24) and the radio frequency antenna slot (25) are respectively provided with a top cover (3) and an antenna cover (4), wherein the battery is placed in the battery hole (26) to constitute the power module, the wireless antenna is placed in the radio frequency antenna slot (25) to constitute the wireless transceiver module, and the microcontroller is placed in the PCB slot (24) to constitute the control module.

5. The sensor for casing makeup measurement according to claim 4, characterized in that, the battery hole (26) is internally provided with a battery box (12) and a battery box cover (10) with a pull ring (11), the bottom of the battery box (12) is provided with a battery box upper bottom sheet (13) and a battery box lower bottom sheet (14); the pull ring (11) is hinged in the groove at the end of the battery box cover (10) to facilitate unfolding and folding, wherein the bottom of the battery box (12) is provided with a through hole, and the battery box upper bottom sheet (13) and the battery box lower bottom sheet (14) are sequentially assembled at both ends of the through hole in the bottom of the battery box (12). The battery hole (26) is provided with a battery cover (5), the outward protruding section of the battery cover (5) is provided with a buckle (9), the folding surface of the buckle (9) is in abutment with the axial end surface of the explosion-proof shell (2) for preventing the battery box (12) from rotating, the outward protruding section of the battery cover (5) is transversely provided with a through hole, an open pin (7) is inserted into the through hole, the battery box (12) is provided with a gasket (8), the gasket (8) is located on the inner side of the open pin (7), and the outward side of the battery cover (5) is provided with a rope buckle (6).

6. The sensor for measuring the make-up of a casing thread according to claim 1, characterized in that, The flange plate (20) is provided on the strain shaft (1), a plurality of first positioning grooves (202) are arranged on the side of the flange plate (20) facing the explosion-proof shell (2), the explosion-proof shell (2) is provided with second positioning grooves (204) corresponding to the first positioning grooves (202), a positioning pin (21) is movably arranged in the space formed by the first positioning grooves (202) and the second positioning grooves (204), the groove wall of the first positioning groove (202) is provided with an outwardly extending positioning hole (203), a fastening screw (22) for clamping the positioning pin (21) is matched in the positioning hole (203), and the strain shaft (1) is provided with a circular groove (300) corresponding to the radial end of the positioning pin (21). The first positioning grooves (202) are provided with fixing holes (201) on both sides, and the fixing holes (201) are matched with connecting bolts (19) for connecting with the explosion-proof shell (2).

7. The sensor for measuring the make-up of a casing thread according to claim 4, characterized in that, The explosion-proof shell (2) is symmetrically provided with two grooves (a) on the outer periphery, one side wall of the groove (a) is provided with a battery hole (26) extending in the same direction and a through hole for communicating with the PCB groove (24); The other side wall of the groove (a) is provided with a processing hole for penetrating the radio frequency antenna groove (25), the distal end of the processing hole forms a through hole for communicating with the PCB groove (24), and the mouth end of the processing hole is provided with a large screw cap (23).

8. The sensor for measuring the make-up of a casing thread according to claim 1, characterized in that, The signal acquisition module integrates a three-axis gyroscope for collecting the number of thread make-ups; The signal acquisition module further includes an A / D conversion circuit and a temperature sensor, which are respectively used for analog-digital conversion of the Wheatstone bridge signal and real-time temperature measurement and alarm of the working area.

9. A sensor for making up measurements on a casing, according to claim 1, characterized in that, The Wheatstone bridge temperature compensation circuit includes: differential operational amplifiers A1, A2, A3, pull-up resistors R1, R2, R3, R8, strain gauges Ra, Rb, Rc, Rd, resistors R6, R7, R4, R5, R9, R10, R11 and R13. One end of the pull-up resistor R2 is connected with the power supply, and the other end is connected with the non-inverting input terminal of the differential operational amplifier A1; one end of the pull-up resistor R3 is connected with the non-inverting input terminal of the differential operational amplifier A1, and the other end is grounded; one end of the pull-up resistor R1 is connected with the inverting input terminal of the differential operational amplifier A1, one end of the strain gauge Rb and one end of the strain gauge Rd, and the other end is grounded; One end of the resistor R6 is connected with the power supply, and the other end is connected with the non-inverting input terminal of the differential operational amplifier A2; one end of the resistor R7 is connected with the power supply, and the other end is grounded; one end of the resistor R4 is connected with the output terminal of the differential operational amplifier A1, and the other end is connected with the inverting input terminal of the differential operational amplifier A2; one end of the pull-up resistor R8 is connected with the output terminal of the differential operational amplifier A2, and the other end is connected with the pull-up resistor R1; one end of the resistor R5 is connected with the resistor R4, and the other end is connected with the resistor R8; One end of the strain gauge Ra is connected with the output terminal of the differential operational amplifier A1, and the other end is connected with the strain gauge Rb and the resistor R13; one end of the strain gauge Rc is connected with the output terminal of the differential operational amplifier A1, and the other end is connected with the strain gauge Rd and the resistor R9; the non-inverting input terminal of the differential operational amplifier A3 is connected with the resistor R9, the inverting input terminal is connected with the resistor R13, one end of the resistor R10 is connected with the resistor R13, and the other end is connected with the output terminal of the differential operational amplifier A3.

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