Wellhead casing plasma cutting device

Abstract

The utility model relates to a plasma cutting device for a wellhead casing, a rotating mechanism in the plasma cutting device is provided with a turntable assembly and a turntable bracket, a plasma cutting torch is arranged in a turntable of the turntable assembly, and a butt-joint transmission chain is fixed on the outer edge of the turntable; a cutting motor and a chain wheel are mounted in the turntable bracket; the chain wheel is mounted at the top of a transmission shaft of a driven wheel mounted in a transmission shaft shell; the upper chuck and the lower chuck are fixedly connected with the transmission shaft shell; the chain wheel is meshed with the transmission chain; a rigid clamping jaw and a flexible clamping jaw in the self-positioning sleeve clamping mechanism are respectively fixed on movable nuts in the sliding table base; an output shaft of a sleeve clamping motor mounted at one end of the sliding table base is connected with one end of a lead screw mounted in the two movable nuts; the sliding table base is connected with the transmission shaft shell through a connecting support. And on the premise of ensuring reliable work and safe use of the cutting device, the labor intensity of workers can be effectively reduced, and the cutting efficiency of the wellhead casing pipe is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the cutting device of the wellhead casing of petroleum industry, more particularly to a wellhead casing plasma cutting device. BACKGROUND

[0002] In the process of oilfield drilling operation, the procedure after casing is finished and cementing operation is: cutting casing, polishing casing bevel, installing casing head and wellhead equipment such as well packer.

[0003] Before this step of cutting casing, generally need to punch the casing to discharge the internal accumulated water and silt, then use oxyacetylene cutting machine to cut the casing above the punching position, otherwise the internal pressure slurry will make oxyacetylene torch reheat, there is a security risk, its operation process is complex, and the cutting efficiency is low. The cutting quality of casing will affect the operation efficiency of subsequent polishing bevel and welding, and the casing end surface after cutting is required to obtain lower roughness and cutting angle and narrower heat affected zone width. The working environment of drilling platform is complex, the space is small, and the devices on the platform are closely spaced, so the outer dimension of the wellhead casing cutting equipment has a relatively strict requirement.

[0004] At present, the methods of cutting petroleum casing at home and abroad mainly include the following methods of abrasive water jet cutting, chemical cutting, and shaped charge cutting:

[0005] The abrasive water jet cutting technology is a cold cutting technology, which can cut metal casing. The technology realizes pressure increase by adding abrasive particles such as diamond sand and copper slag in water, and high-speed liquid flow is formed after pressure increase, and the speed of abrasive liquid flow can reach 600-1000 m / s. However, the cutting cost is high, the abrasive also accelerates the nozzle loss, and the sealing performance and requirement of the cutting system are also very strict. At the same time, in order to obtain high efficiency of cutting effect, the abrasive water jet needs to have a suitable jet speed, these factors make the structure of the system more complex, and the application is limited in the casing cutting operation.

[0006] The chemical cutting technology is to use the substance filled in the casing to generate chemical change, generate high temperature and high pressure chemical reaction and corrode and cut the casing. The casing section formed by using the chemical cutting method is relatively smooth, the pipe mouth outer diameter is relatively larger than the original outer diameter, the cutting is not limited by the casing material and size, and the cutting effect is good. However, since the liquid sprayed by the chemical cutting is fluoride, it has strong toxicity, and will cause great harm to biology, human beings and the surrounding ecological environment, so its use is also limited.

[0007] The energy-gathering explosion cutting is to cut the casing by using the energy generated by the explosion of the explosive. When cutting, the energy-gathering cutting tool is lowered to the casing to be cut, and the casing is cut by using the high-pressure gas flow generated after the explosion of the explosive. The appearance of the casing break is extremely irregular. At the same time, the amount of explosive is not easy to control. When the amount is less, the casing cannot be completely cut off; when the amount is too much, a huge amount of energy is released to impact the ecological environment around the oil well, causing serious damage.

[0008] The commonly used casing cutting methods at home and abroad have the problems of low cutting efficiency, complex cutting process, high cost and the like, and the plasma cutting with different working gases can cut various conventional cutting metals that are difficult to cut. The plasma cutting has the advantages of fast cutting speed, smooth cutting surface and small thermal deformation, but the commonly used plasma casing cutting device at home has the disadvantages of difficult positioning, time-consuming installation and unstable cutting process.

[0009] The Chinese patent authorized publication No. CN112253027B discloses a marine abandoned wellhead cutting device based on plasma arc cutting, which comprises a supporting mechanism, a rotating mechanism, a feeding mechanism, a cutting mechanism and a guiding mechanism. The supporting mechanism is used for providing downhole support for the whole device, ensuring that the lower rotating mechanism is located at the center of the casing. The rotating mechanism is used for driving the rotating of the feeding mechanism and the cutting mechanism to achieve the purpose of cutting the casing. The feeding mechanism is used for adjusting the distance between the cutting mechanism and the inner wall of the casing. The cutting mechanism is used for generating high-temperature plasma arc to realize cutting operation. The guiding mechanism provides guidance for the whole device, ensuring that the device can be smoothly lowered along the casing axis.

[0010] The above-mentioned invention is a cutting device specially used for the cutting of the marine abandoned wellhead. The device has the advantages of simple and compact structure, good stability, low equipment manufacturing cost, wide application range, small cutting force, no vibration, good economic benefit and market value. However, the device can only be used for cutting the casing of the abandoned wellhead.

[0011] There is no report on the plasma cutting device for the casing of the wellhead in the cementing operation at home and abroad at present. Therefore, it is urgent to develop a casing cutting device with high efficiency, compactness and safe working for use in the drilling operation. SUMMARY

[0012] The utility model aims at providing a wellhead casing plasma cutting device for cutting the casing of the wellhead in the cementing operation, overcoming the problems of low cutting efficiency, complex cutting process, high cost and the like in the cementing operation of the oil field. The device can be suitable for the operation space of the wellhead and meet the use regulations of the oil field production site. Under the premise of ensuring the reliable working and safe use of the cutting device, the labor intensity of workers is reduced, and the cutting efficiency of the casing of the wellhead is improved.

[0013] In order to achieve the above object, the utility model discloses the following scheme: a wellhead casing plasma cutting device is equipped with a plasma cutting torch, wherein: the rotating mechanism is equipped with a turntable assembly and a turntable support, the turntable of the turntable assembly is equipped with the plasma cutting torch, the turntable is a butt joint type disc body and is installed between the upper chuck and the lower chuck with casing inlet and outlet, the outer edge of the turntable is fixed with butt joint type transmission chain; the turntable support is equipped with a cutting motor and a sprocket, the driving wheel and the driven wheel are connected through a wheel belt, the transmission shaft top of the driven wheel installed in the transmission shaft shell is equipped with the sprocket; the upper chuck and the lower chuck are fixedly connected with the transmission shaft shell, and the sprocket is engaged with the transmission chain; the rigid clamping jaw and the flexible clamping jaw in the self-positioning casing clamping mechanism are fixed on the movable nut in the slide base respectively, and the output shaft of the casing clamping motor installed in one end of the slide base is connected with one end of the lead screw installed in the two movable nuts; the slide base and the transmission shaft shell are connected through the connecting support.

[0014] Preferably, the connecting support is a triangular support, and two right-angle sides are respectively connected with the bottom surface of the slide base and the lower end of the transmission shaft shell through bolts; and the oblique side of the connecting support faces the side of the driven wheel.

[0015] Preferably, the slide base is a U-shaped seat, the casing clamping motor is fixed in the side plate on one side of the slide base where the rigid clamping jaw is installed through bolts, and the output shaft is connected with one end of the lead screw in the movable nut where the rigid clamping jaw is fixed; the external threads at both ends of the lead screw are reverse external threads.

[0016] Preferably, the rigid clamping jaw and the flexible clamping jaw are fixedly connected on the movable nut through bolts; the reverse external threads at both ends of the lead screw are respectively connected with the reverse internal threads in the two movable nuts; the outer circle of the lead screw is a non-equal-diameter outer circle, and the large-diameter light rod section in the middle part is a locking section, and the outer diameters of the reverse thread sections on both sides are smaller than that of the locking section in the middle part.

[0017] Preferably, the rigid clamping jaw is provided with a clamping jaw clamping plate, a clamping jaw stand, a rubber pad top plate and a rigid clamping jaw rubber pad, the rubber pad top plate and the clamping jaw stand are fixedly connected with the two clamping jaw clamping plates on both sides through bolts; the two rigid clamping jaw rubber pads are fixed between the two clamping jaw clamping plates and tightly contact the upper and lower sides of the rubber pad top plate.

[0018] Preferably, the flexible jaw is provided with a photoelectric sensor, a jaw edge plate, an angle frame, a support plate, a flexible clamping block and a spring, the jaw edge plate is provided with two pieces and the lower part is provided with a jaw guide rail, the flexible clamping block is provided with a jaw sliding block on the lower part of two sides, the jaw sliding block is matched with the jaw guide rail provided on the inner side of the two jaw edge plates, the flexible clamping block can slide along the jaw guide rail, the photoelectric sensor is fixed on the upper part of the angle frame, the light shield plate of the photoelectric sensor is fixed on the upper surface of the flexible clamping block and corresponds to the photoelectric sensor, the photoelectric sensor is connected with the controller of the sleeve clamping motor through a wire, the top of the flexible clamping block is fixed with a baffle, the jaw edge plate is fixed on the outer side of the angle frame, and the angle frame and the support plate are fixed between the two jaw edge plates through bolts.

[0019] Preferably, the flexible clamping block is a U-shaped hollow block body, and a clamping pad mounting block is fixed on the plate body on the upper and lower side end faces of the U-shaped mouth through bolts, and a flexible clamping block rubber pad is further fixed on the upper end face of the clamping pad mounting block; spring stand columns are arranged on the upper and lower sides of the angle frame and correspond to the clamping pad mounting block, flanges are arranged on the front ends of the spring stand columns, and springs are arranged outside the spring stand columns between the flanges and the angle frame; the flanges can be in contact with the clamping pad mounting blocks fixed on the two sides of the front end U-shaped mouth of the flexible clamping block.

[0020] Preferably, the cutting motor is fixed in the motor seat arranged at the front end of the transmission shaft shell, and the motor seat is a right-angled triangular seat; the butt joint disc bodies of the rotating disc are connected through a connecting plate, the connecting plate is connected to the disc bodies on the two sides of the butt joint of the rotating disc through a pin shaft; the butt joint of the transmission chain corresponds to the butt joint of the rotating disc, and the butt joints of the rotating disc and the transmission chain correspond to the sleeve inlets and outlets of the upper chuck and the lower chuck.

[0021] Preferably, the outer edge of the lower chuck is provided with a clamping groove matched with a clamping table arranged on the inner edge of the rotating disc; at least one row of bolt fixing holes is arranged in the disc bodies of the upper chuck and the lower chuck and corresponds to the sleeve inlets and outlets, the bolt fixing holes are arranged in the disc bodies on the inner side of the clamping groove of the lower chuck, and the disc bodies of the upper chuck and the lower chuck are fixedly connected with the transmission shaft shell through bolts.

[0022] Preferably, more than four weight reduction holes are arranged in the disc body corresponding to the butt joint of the rotating disc, the plasma cutting torch is arranged in the plasma cutting torch mounting hole arranged in the disc body of the rotating disc, and the weight reduction holes are uniformly distributed on the two sides of the plasma cutting torch mounting hole; the mounting position of the lower end of the connecting support is higher than the lower end of the sliding table base, the mounting position of the lower end of the driving wheel and the driven wheel of the cutting motor is higher than the lower end of the connecting support; the well mouth plasma cutting device can be placed on the ground of the operation well mouth or fixed on the support on the ground of the operation well mouth.

[0023] Compared with the prior art, the main use effects of the utility model are as follows:

[0024] The utility model provides a special cutting device for wellhead casing of petroleum industry, is applicable to the narrow operation space of wellhead, accords with the use regulation of oilfield production site. Under the premise of guaranteeing that cutting device works reliably and uses safely, can effectively reduce the labor intensity of worker, improves the cutting efficiency of wellhead casing. Mainly reflects:

[0025] First, the whole disc of the device is annular, which can be split during use to facilitate installation from the side to the outside of the casing to be cut, and the disc assembly can be cut after starting the cutting motor by the ion cutting torch, achieving more stable and continuous cutting conditions.

[0026] Second, the rigid clamping jaw and flexible clamping jaw in the self-positioning casing clamping mechanism are driven by a casing clamping motor, which improves positioning accuracy and facilitates installation of the device. The rigid clamping jaw and flexible clamping jaw are combined to achieve self-positioning clamping of the casing to be cut. In addition, a photoelectric sensor is provided inside the flexible clamping jaw. During the clamping process of the casing to be cut, the clamping force is controllable as long as it does not exceed the maximum compression of the spring, preventing the motor from overheating or even being damaged due to stalling of the casing clamping motor, and improving the service life of the motor.

[0027] Third, the self-positioning casing clamping mechanism can effectively improve the positioning and clamping efficiency of the casing to be cut and the service life of the device.

[0028] Fourth, the cutting process of the casing to be cut is driven by a cutting motor, and the power is transmitted by a sprocket and a transmission chain to achieve a stable and continuous cutting process.

[0029] In summary, the utility model has significant use effects and can produce good economic and social benefits, and has good application value. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings are used to provide a further understanding of the utility model and constitute a part of the specification, which is used together with the embodiments of the utility model to explain the utility model and does not constitute a limitation on the utility model.

[0031] In the drawings: Figure 1 It is the overall structure schematic diagram of the utility model.

[0032] Figure 2 It is Figure 1 The structure schematic diagram of the rotating mechanism in

[0033] Figure 3 It is Figure 2 The structure schematic diagram of the disc assembly in

[0034] Figure 4 is Figure 2 Structure diagram of the rotating disc support.

[0035] Figure 5 is Figure 1 Structure diagram of the self-positioning sleeve clamping mechanism.

[0036] Figure 6 is Figure 5 Structure diagram of the rigid clamping jaw.

[0037] Figure 7 is Figure 5 Structure diagram of the flexible clamping jaw.

[0038] Figure 8 is Figure 7 Top view of the device.

[0039] In the figure:

[0040] Sleeve to be cut 1;

[0041] Rotating mechanism 2:

[0042] Rotating disc assembly 21: upper chuck 211, lower chuck 212, rotating disc 213, connecting rod 214, plasma cutting torch mounting hole 215, transmission chain 216, rotating disc support 22, cutting motor 221, driving wheel 222, chain wheel 223, motor base 224, transmission shaft housing 225, driven wheel 226;

[0043] Self-positioning sleeve clamping mechanism 3:

[0044] Rigid clamping jaw 31: rigid clamping jaw rubber pad 311, rubber pad top plate 312, clamping jaw stand 313, clamping jaw clamping plate 314;

[0045] Flexible clamping jaw 32: clamping jaw edge plate 321, clamping jaw guide rail 3211, clamping jaw sliding block 3212, corner bracket 322, support plate 323; flexible clamping block 324, baffle 3241, spring 325, spring stand 326, flange 327, clamping pad mounting block 328, flexible clamping block rubber pad 329;

[0046] Sleeve clamping motor 33, sliding table base 34, lead screw 35, movable nut 36;

[0047] Connecting support 4. DETAILED DESCRIPTION

[0048] The accompanying drawings are only used for reference and illustration, and do not limit the protection scope of the utility model. The technical solutions in the embodiments of the utility model will be clearly and completely described below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0049] In order to make the purpose, technical scheme and advantages of the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model.

[0050] In the description of the utility model, it should be understood that the orientation or position relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model. In addition, in the description of the utility model, the meaning of "multiple" is two or more, unless otherwise explicitly and specifically limited.

[0051] Referring to Figure 1 - Figure 8 A wellhead casing plasma cutting device is provided with a plasma cutting torch, wherein:

[0052] The rotating mechanism 2 is provided with a turntable assembly 21 and a turntable support 22, the turntable 213 of the turntable assembly 21 is provided with the plasma cutting torch, the turntable 213 is a butt joint type disc body and is installed between the upper chuck 211 and the lower chuck 212 with casing inlet and outlet on the inner side, and the outer edge of the turntable 213 is fixed with a butt joint type transmission chain 216;

[0053] The turntable support 22 is provided with a cutting motor 221 and a sprocket wheel 223, the driving wheel 222 and the driven wheel 226 are connected through a belt, the transmission shaft at the top of the driven wheel 226 installed in the transmission shaft shell 225 is provided with the sprocket wheel 223;

[0054] The upper chuck 211 and the lower chuck 212 are fixedly connected with the transmission shaft shell 225, and the sprocket wheel 223 is engaged with the transmission chain 216;

[0055] The rigid clamping jaw 31 and the flexible clamping jaw 32 in the self-positioning casing clamping mechanism 3 are fixed on the movable nuts 36 in the slide base 34 respectively, and the output shaft of the casing clamping motor 33 installed on one end of the slide base 34 is connected with one end of the lead screw 35 installed in the two movable nuts 36.

[0056] The slide base 34 is connected with the transmission shaft housing 225 through the connecting support 4.

[0057] The rotating mechanism 2 in the utility model can make the plasma cutting torch installed therein rotate cutting around the casing to be cut 1, and the self-positioning casing clamping mechanism 3 is used for clamping the casing to be cut 1. The rotating mechanism 2 and the self-positioning casing clamping mechanism 3 are fixed and connected through the connecting support 4 between the slide base 34 and the transmission shaft housing 225.

[0058] The rotating disc 213 in the utility model is a butt joint type disc body, the chuck 211 and the lower chuck 212 are provided with casing import and export, and the transmission chain 216 fixed on the outer edge of the rotating disc 213 is also a butt joint type chain; the self-positioning casing clamping mechanism 3 is provided with the rigid clamping jaw 31 and the flexible clamping jaw 32 driven by the casing clamping motor 33. The above-mentioned component features determine that the utility model can be inserted to the outside of the casing to be cut 1 in the well mouth, so that the casing to be cut 1 is placed in the device and the integrity of the transmission chain 216 on the rotating disc 213 can be ensured.

[0059] The casing clamping motor 33 drives the lead screw 35 to move, so as to drive the movable nut 36 to move, and the self-positioning casing clamping mechanism 3 can be clamped on the outside of the casing to be cut 1.

[0060] The cutting motor 221 drives the driving wheel 222 to rotate and transmits power to the sprocket wheel 223 through the driven wheel 226, the sprocket wheel 223 drives the transmission chain 216 to drive the rotating disc 213 in the rotating mechanism 2 to rotate between the upper chuck 211 and the lower chuck 212, so as to drive the plasma cutting torch in the rotating disc 213 to complete the movement around the casing to be cut 1, and the casing to be cut 1 is completely cut off.

[0061] The utility model has the advantages of reasonable structure, reliable work, small volume, and is suitable for narrow operation space of well mouth of oil well, and meets the use regulations of oil field production site. When the casing needs to be cut during the cementing operation process, the device is used for cutting operation on the casing to be cut 1, under the premise of ensuring reliable work and safe use, the labor intensity of workers can be effectively reduced, and the cutting efficiency of the casing is improved. The problems of low cutting efficiency, complex cutting process and high cost of casing cutting in the well mouth during the cementing operation process of the oil field can be overcome, and the utility model has remarkable use effect.

[0062] On the basis of the above-mentioned embodiment one, the utility model also has the following embodiments:

[0063] A preferred embodiment: Figure 1 、 Figure 4 and Figure 5 Taking the orientation shown in as an example, the connecting bracket 4 is a triangular bracket and its two right-angled sides are respectively connected to the bottom surface of the slide base 34 and the lower end of the transmission shaft housing 225 by bolts; the oblique side of the connecting bracket 4 faces the side of the driven wheel 226.

[0064] A preferred embodiment: the slide base 34 is a U-shaped seat, the sleeve clamping motor 33 is fixed by bolts in the side plate on one side of the slide base 34 on which the rigid clamping claw 31 is installed, and the output shaft is connected to one end of the screw 35 in the movable nut 36 that fixes the rigid clamping claw 31; the external threads at both ends of the screw 35 are reverse external threads.

[0065] In a preferred embodiment, the rigid clamping claw 31 and the flexible clamping claw 32 are fixedly connected to the movable nut 36 by bolts; the reverse external threads at both ends of the lead screw 35 are respectively connected to the reverse internal threads in the two movable nuts 36; the outer diameter of the lead screw 35 is non-uniform, the large diameter polished rod section in the middle is a locking section, and the outer diameter of the reverse threaded sections on both sides is smaller than the locking section in the middle. When the casing 1 to be cut needs to be clamped, the casing clamping motor 33 drives the lead screw 35 to rotate, and the movable nuts 36 connected to both sides of the lead screw 35 drive the rigid clamping claw 31 and the flexible clamping claw 32 fixed thereon to move toward the middle simultaneously, clamping the casing 1 to be cut; when the casing 1 to be cut needs to be loosened, the casing clamping motor 33 drives the lead screw 35 to rotate in the opposite direction, and the movable nuts 36 connected to both sides of the lead screw 35 drive the rigid clamping claw 31 and the flexible clamping claw 32 mounted thereon to move toward both sides, loosening the casing 1 to be cut, making the process of clamping and loosening the casing 1 to be cut more convenient and quick.

[0066] A preferred embodiment: see Figure 6 The rigid claw 31 is provided with a claw splint 314, a claw column 313, a rubber pad top plate 312 and a rigid claw rubber pad 311. The rubber pad top plate 312 and the claw column 313 are fixedly connected to the two claw splints 314 on both sides by bolts; the two rigid claw rubber pads 311 are fixed between the two claw splints 314 on the upper and lower sides of the rubber pad top plate 312. Figure 6 It is a schematic diagram of the structure after the front side claw clamping plate 314 is removed. The claw clamping plate 314 in the figure is the one installed on the other side of the rubber pad top plate 312 and the rigid claw rubber pad 311.

[0067] A preferred embodiment: the flexible jaw 32 is provided with a photoelectric sensor 320, a jaw edge plate 321, an angle frame 322, a support plate 323, a flexible clamping block 324 and a spring 325, the jaw edge plate 321 is provided with two plates, and the lower part of each plate is provided with a jaw guide rail 3211; the flexible clamping block 324 is provided with a jaw sliding block 3212 on the lower side, which is matched and installed with the jaw guide rail 3211 provided on the inner side of the two jaw edge plates 321, and the flexible clamping block 324 can slide along the jaw guide rail 3211; the photoelectric sensor 320 is fixed on the upper part of the angle frame 322, and the light shield plate 330 of the photoelectric sensor 320 is fixed on the upper surface of the flexible clamping block 324, and the photoelectric sensor 320 is connected with the controller of the sleeve clamping motor 33 through a wire; the top of the flexible clamping block 324 is fixed with a baffle 3241, and the jaw edge plate 321 is fixed on the outer side of the angle frame 322, and the angle frame 322 and the support plate 323 are fixed between the two jaw edge plates 321 through bolts.

[0068] A preferred embodiment: the flexible clamping block 324 is a U-shaped hollow block, and a clamping pad mounting block 328 is fixed on the upper surface of the plate body on the upper and lower side ends of the U-shaped opening through bolts, and a flexible clamping block rubber pad 329 is also fixed on the upper end surface of the clamping pad mounting block 328; the angle frame 322 is provided with a spring stand 326 corresponding to the clamping pad mounting block 328 on the upper and lower sides, the front end of the spring stand 326 is provided with a flange 327, and the spring 325 is installed outside the spring stand 326 between the flange 327 and the angle frame 322; the flange 327 can contact the clamping pad mounting block 328 fixed on the two sides of the front end of the U-shaped opening of the flexible clamping block 324. On the one hand, it can enhance the support strength of the clamping pad mounting block 328; on the other hand, since the light shield plate 330 of the photoelectric sensor 320 is installed on the flexible clamping block 324, when the spring 325 in the flexible jaw 32 is gradually compressed and drives the flexible clamping block 324 to slide along the jaw guide rail 3211 to the light shield plate 330 and blocks the photoelectric switch of the photoelectric sensor 320, the sleeve clamping motor 33 stops rotating, and the lead screw 35 is locked under the action of the static torque of the motor. During the entire clamping process of the to-be-cut sleeve pipe 1, as long as the maximum compression amount of the spring 325 is not exceeded, the clamping force range of the rigid jaw 31 and the flexible jaw 32 is controllable, and the sleeve clamping motor 33 will not be blocked. It can avoid the heating of the motor caused by this, and can improve the service life of the motor.

[0069] A preferred embodiment: the cutting motor 221 is fixed in the motor seat 224 provided at the front end of the transmission shaft housing 225, and the motor seat 224 is a right-angled triangular seat, which facilitates the installation of the cutting motor 221 ；The abutting disc body of the rotating disc 213 is connected through the connecting plates 214 which are connected in the two disc bodies at the abutting position of the rotating disc 213 through pin shafts; the abutting position of the transmission chain 216 corresponds to the abutting position of the rotating disc 213, and the abutting positions of the rotating disc 213 and the transmission chain 216 correspond to the sleeve inlet and outlet of the upper chuck 211 and the lower chuck 212.

[0070] A preferred embodiment: the outer edge of the lower chuck 212 is provided with a clamping groove matched with a clamping table provided in the inner edge of the rotating disc 213; at least one row of bolt fixing holes is arranged in the disc body of the upper chuck 211 and the lower chuck 212 corresponding to the sleeve inlet and outlet, the bolt fixing holes are arranged in the disc body inside the clamping groove of the outer edge of the lower chuck 212, and the disc body of the upper chuck 211 and the lower chuck 212 is fixedly connected with the transmission shaft shell 225 through bolts. In this way, the upper chuck 211 and the lower chuck 212 are fixed outside the to-be-cut sleeve 1, only the rotating disc 213 driven by the transmission chain 216 rotates and drives the plasma torch installed therein to rotate and cut together outside the to-be-cut sleeve 1.

[0071] A preferred embodiment: four or more weight reduction holes are arranged in the disc body corresponding to the abutting position of the rotating disc 213, the plasma torch is installed in the plasma torch installation hole 215 arranged in the disc body of the rotating disc 213, and the weight reduction holes are uniformly distributed on the two sides of the plasma torch installation hole 215; the installation position of the lower end of the connecting support 4 is higher than the lower end of the sliding table base 34, and the installation position of the lower end of the driving wheel 222 and the driven wheel 226 of the cutting motor 221 is higher than the lower end of the connecting support 4; the wellhead sleeve plasma cutting device can be placed on the ground at the operation wellhead or fixed on the support on the ground at the operation wellhead.

[0072] The utility model discloses through the pin shaft of pulling up two connecting plates 214 opens the abutting position of rotating disc 213, forms a gap, makes the cutting sleeve 1 with the inside of the device, and then installs two connecting plates 214, guarantees the completeness of transmission chain 216 on rotating disc 213.

[0073] Starting the sleeve clamping motor 33 drives the lead screw 35 to move, so as to drive the two movable nuts 36 to drive the rigid clamping jaw 31 and the flexible clamping jaw 32 to clamp the outside of the to-be-cut sleeve 1; the cutting motor 221 drives the driving wheel 222 to transmit power to the sprocket wheel 223 through the driven wheel 226, the sprocket wheel 223 drives the transmission chain 216 to drive the rotating disc 213 in the rotating mechanism 2 to rotate between the upper chuck 211 and the lower chuck 212, so that the plasma torch in the plasma torch installation hole 215 completes the movement of cutting a circle around the to-be-cut sleeve 1.

[0074] The utility model discloses reasonable structure, reliable work, small, be applicable to the narrow operation space of oil well wellhead, meet the use regulation of oilfield production site, when the wellhead casing needs to use plasma cutting processing, use this device, under the premise of guaranteeing reliable work and safe use, can reduce the labor intensity of worker, improve cutting efficiency.

[0075] The above-described embodiments are merely typical embodiments, but the utility model is not limited to these embodiments, and a person skilled in the art can make modifications without departing from the spirit and inspiration of the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, a person skilled in the art can modify the technical solutions recorded in the foregoing embodiments or make equivalent replacement to part of the technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and concept of the utility model should be included in the protection scope of the utility model. Therefore, the protection scope is not limited to the foregoing description.

Claims

1. A wellhead casing plasma cutting apparatus provided with a plasma torch, characterized in that: The rotating mechanism is provided with a rotating disc assembly and a rotating disc support. The rotating disc of the rotating disc assembly is provided with a plasma cutting torch. The rotating disc is a butt joint disc body and is mounted between an upper chuck and a lower chuck with a sleeve inlet and outlet. The outer edge of the rotating disc is fixed with a butt joint transmission chain. The rotating disc support is provided with a cutting motor and a sprocket. The driving wheel and the driven wheel are connected through a belt. The top of the transmission shaft of the driven wheel installed in the transmission shaft shell is provided with a sprocket. The upper chuck and the lower chuck are fixedly connected with the transmission shaft shell. The sprocket is engaged with the transmission chain. The rigid clamping jaw and the flexible clamping jaw in the self-positioning sleeve clamping mechanism are fixed on the movable nut in the slide base respectively. The output shaft of the sleeve clamping motor installed at one end of the slide base is connected with one end of the lead screw installed in the two movable nuts. The slide base is connected with the transmission shaft shell through a connecting support.

2. A wellhead casing plasma cutting apparatus as defined in claim 1 wherein, The connecting support is a triangular support, and two straight angle sides are respectively connected with the bottom surface of the slide base and the lower end of the transmission shaft shell through bolts. The inclined side of the connecting support is towards the side of the driven wheel.

3. A wellhead casing plasma cutting apparatus as claimed in claim 1 or 2, characterised in that, The slide base is a U-shaped seat. The sleeve clamping motor is fixed in the side plate on one side of the slide base where the rigid clamping jaw is installed through bolts, and the output shaft is connected with one end of the lead screw in the movable nut where the rigid clamping jaw is fixed. The external threads at both ends of the lead screw are reverse external threads.

4. A wellhead casing plasma cutting apparatus as defined in claim 3 wherein, The rigid clamping jaw and the flexible clamping jaw are fixedly connected on the movable nut through bolts. The reverse external threads at both ends of the lead screw are respectively connected with the reverse internal threads in the two movable nuts. The outer circle of the lead screw is a non-equal-diameter outer circle, and the large-diameter light rod section in the middle is a locking section. The outer diameters of the reverse thread sections on both sides are smaller than that of the locking section in the middle.

5. A wellhead casing plasma cutting apparatus as defined in claim 4 wherein, The rigid clamping jaw is provided with a clamping jaw clamping plate, a clamping jaw stand, a rubber pad top plate and a rigid clamping jaw rubber pad. The rubber pad top plate and the clamping jaw stand are fixedly connected with the two clamping jaw clamping plates on both sides through bolts. The two rigid clamping jaw rubber pads are fixed between the two clamping jaw clamping plates and tightly contact the upper and lower sides of the rubber pad top plate.

6. A wellhead casing plasma cutting apparatus as defined in claim 4 wherein, The flexible clamping jaw is provided with a photoelectric sensor, a clamping jaw edge plate, an angle bracket, a support plate, a flexible clamping block and a spring. The clamping jaw edge plate is provided with two clamping jaw edge plates, and the lower part of each clamping jaw edge plate is provided with a clamping jaw guide rail. The clamping jaw sliding blocks arranged on the lower sides of the flexible clamping block are matched and installed with the clamping jaw guide rails arranged on the inner sides of the two clamping jaw edge plates, and the flexible clamping block can slide along the clamping jaw guide rails. The photoelectric sensor is fixed on the upper part of the angle bracket. The light shield plate of the photoelectric sensor corresponds to the photoelectric sensor and is fixed on the upper surface of the flexible clamping block. The photoelectric sensor is connected with the controller of the sleeve clamping motor through a wire. The top of the flexible clamping block is fixed with a baffle. The clamping jaw edge plate is fixed on the outer side of the angle bracket. The angle bracket and the support plate are fixed between the two clamping jaw edge plates through bolts.

7. A wellhead casing plasma cutting apparatus as defined in claim 6 wherein, The flexible clamping block is a U-shaped hollow block body. The clamping pad mounting block is fixed on the plate body on the upper and lower side end faces of the U-shaped mouth through bolts. The flexible clamping block rubber pad is also fixed on the upper end face of the clamping pad mounting block. The spring stand is arranged on the upper and lower sides of the angle bracket corresponding to the clamping pad mounting block. The front end of the spring stand is provided with a flange. The spring is installed on the outside of the spring stand between the flange and the angle bracket. The flange can contact the clamping pad mounting block fixed on the two sides of the front end U-shaped mouth of the flexible clamping block.

8. A wellhead casing plasma cutting apparatus as defined in claim 1 wherein, The cutting motor is fixed in the motor seat arranged at the front end of the transmission shaft shell, and the motor seat is a right triangle seat; the butt joint disc body of the rotating disc is connected through the connecting plate, the connecting plate is connected in the two disc bodies at the butt joint of the rotating disc through the pin shaft; the butt joint of the transmission chain corresponds to the butt joint of the rotating disc, and the butt joints of the rotating disc and the transmission chain correspond to the inlet and outlet of the sleeve of the upper chuck and the lower chuck.

9. A wellhead casing plasma cutting apparatus as defined in claim 8 wherein, The outer edge of the lower chuck is provided with a clamping groove matched with the clamping table arranged at the inner edge of the rotating disc; at least one row of bolt fixing holes is arranged in the disc body of the upper chuck and the lower chuck corresponding to the inlet and outlet of the sleeve, the bolt fixing holes are arranged in the disc body inside the clamping groove of the outer edge of the lower chuck, and the disc body of the upper chuck and the lower chuck is fixedly connected with the transmission shaft shell through bolts.

10. A wellhead casing plasma cutting apparatus as defined in claim 9 wherein, Four or more weight reduction holes are arranged in the disc body corresponding to the butt joint of the rotating disc, the plasma cutting torch is arranged in the plasma cutting torch mounting hole arranged in the disc body of the rotating disc, the weight reduction holes are uniformly distributed on both sides of the plasma cutting torch mounting hole; the mounting position of the lower end of the connecting support is higher than the lower end of the sliding table base, the mounting position of the lower end of the driving wheel and the driven wheel of the cutting motor is higher than the lower end of the connecting support; the wellhead sleeve plasma cutting device can be placed on the ground of the operation wellhead or fixed on the support on the ground of the operation wellhead.

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