Detection and alarm device for tubing coupling

Abstract

The utility model discloses a tubing coupling detection alarm device which is characterized in that detection flashboards are symmetrically arranged in an inner cavity of an alarm device body, flashboard grooves are respectively formed in the middle parts of the opposite ends of the two detection flashboards, coupling detection wheels are respectively mounted in the two flashboard grooves, and V-shaped grooves are respectively formed in the middle parts of the peripheries of the coupling detection wheels; an oil pipe lifting channel is formed between the V-shaped grooves of the two coupling detection wheels, side covers are fixed to ports of the two sides of the alarm device body respectively, alarm signal rods are symmetrically connected to the sides, close to the side covers, of the detection gate plates, and the middles of the alarm signal rods extend out of guide holes of the side covers respectively. The center of the side, facing the side cover, of the detection gate plate is fixedly connected with a buffer sleeve, the center of the inner end face of the detection gate plate is provided with a sinking groove allowing the outer end of the buffer sleeve to be embedded, the outer end of the buffer sleeve is embedded in the inner stepped hole of the corresponding side cover, and a buffer spring is arranged in an inner cavity of the buffer sleeve. The device can prevent the sealing flashboard from being damaged in the process of lifting the pipe column under pressure, and can avoid the engineering accident that the pipe column falls into a well.

Description

Technical Field

[0001] The utility model relates to an oil pipe coupling detection and alarm device, belonging to the technical field of oilfield downhole operation equipment, and is used for blowout prevention and pollution prevention at the wellhead during major overhaul rotary drilling and milling in downhole operations. Background Technique

[0002] The workover technology with pressure control has been continuously developed in recent years and has played an important role in oilfield development. However, there are still some problems that have not been solved. During construction, the oil pipe passes through the blowout preventer above the wellhead four-way and is lifted out of the wellhead. Since the outer diameter of the coupling connecting the oil pipes is larger than the outer diameter of the oil pipe, when the coupling reaches below the blowout preventer, it is necessary to give an alarm in time to open the blowout preventer. After the coupling passes over the blowout preventer, the blowout preventer should be closed in time to reduce the wellhead overflow.

[0003] During the actual operation process, no good method has been found for the judgment of the coupling, which restricts the improvement of the workover level with pressure control. In the past, a detection device, a non-contact magnetic induction type coupling alarm, was equipped. Before each operation, it needed to be debugged for a long time, and it required personnel with a certain technical level to judge and identify, with a high false alarm rate, so it was difficult to popularize and apply.

[0004] Due to the extremely harsh work environment of workover with pressure control, which is full of many impurities such as sediment, stones, and oil stains, it has a great impact on the extraction of signals. Therefore, whether the coupling alarm can give an accurate alarm is an urgent problem to be solved, and it is required to be able to give an accurate alarm even under harsh environmental conditions such as the presence of oil stains and sand and gravel.

[0005] At present, during the production operation of lifting and lowering oil pipes in oil and gas fields, the lifting of the oil pipe mainly depends on the experience or visual inspection of the driller to open and close the sealing ram in time. If the ram is opened too early, there will be more overflow; if it is opened too late, the coupling will hit the sealing ram of the wellhead blowout preventer, causing damage to the sealing ram and even causing an engineering accident such as the pipe string falling into the well.

[0006] The Chinese invention patent with the publication number of CN 108729907B discloses an intelligent combined coupling alarm device and its usage method. The alarm device includes a movable slip, an oil pipe position prediction assembly, a first cross beam, a second cross beam, a lifting cylinder displacement detection assembly, a single ram blowout preventer, a coupling detection assembly, a third cross beam, a three-ram blowout preventer, and a fourth cross beam. The oil pipe position prediction assembly can detect the position of the coupling, so as to calculate the position of the next coupling; the lifting cylinder displacement detection assembly can measure the distance that the oil pipe moves upward driven by the lifting cylinder; the electrical signals generated by the oil pipe position prediction assembly, the lifting cylinder displacement detection assembly, and the coupling detection assembly are all transmitted to the controller for processing, and the processed signals are transmitted to the single ram blowout preventer. This technical solution has a relatively high degree of intelligence, but it is prone to failure in the harsh on-site working environment, has relatively high requirements for operators, and on-site operators cannot directly observe. Summary of the Invention

[0007] The purpose of this part is to outline some aspects of the embodiments of the present utility model and briefly introduce some preferred embodiments. Simplifications or omissions may be made in this part, as well as in the abstract and the title of the specification of this application, but such simplifications or omissions shall not be used to limit the scope of the present utility model.

[0008] In view of the above-mentioned and / or problems existing in the prior art regarding the hanging and bumping of the gate valve during the tubing string lifting under pressure, the present utility model is proposed.

[0009] The purpose of the present utility model is to overcome the problems existing in the prior art and provide an oil tubing coupling detection and alarm device, which can avoid damage to the sealing gate valve during the tubing string lifting under pressure and prevent engineering accidents such as tubing string falling into the well. At the same time, it has reliable operation, convenient construction, and high economy and practicability.

[0010] To solve the above technical problems, an oil tubing coupling detection and alarm device of the present utility model includes an alarm device body that penetrates vertically. The inner cavity of the alarm device body is symmetrically provided with detection gate valves. The middle parts of the opposite ends of the two detection gate valves are respectively provided with gate valve grooves. Rotatable coupling detection wheels are respectively installed in the two gate valve grooves. The middle parts of the outer circumferences of the two coupling detection wheels are respectively provided with V-shaped grooves. A hoisting and lowering channel for the oil tubing to pass through is formed between the V-shaped grooves of the two coupling detection wheels. Side covers are respectively fixed at the two side ports of the alarm device body. Alarm signal rods are symmetrically connected to the side of the detection gate valve close to the side cover. The middle parts of the alarm signal rods respectively extend out from the guiding holes of the side cover.

[0011] Furthermore, both ends of the central hole of the coupling detection wheel are respectively supported in the middle of the wheel shaft through bearings, and both ends of the wheel shaft are respectively inserted into the shaft holes of the detection gate valve.

[0012] Furthermore, a buffer sleeve is fixedly connected to the center of the side of the detection gate valve facing the side cover. A sinking groove for the outer end of the buffer sleeve to be embedded is provided at the center of the inner end face of the detection gate valve. The outer end of the buffer sleeve is embedded in the inner stepped hole of the corresponding side cover, and a buffer spring is arranged in the inner cavity of the buffer sleeve.

[0013] Furthermore, protective covers are respectively fixed at the centers of the outer end faces of the two side covers, and adjusting shafts are respectively arranged in the protective covers; the inner ends of the buffer springs respectively abut against the centers of the outer end faces of the corresponding detection gate valves, and the outer ends of the buffer springs respectively abut against the inner end faces of the adjusting shafts.

[0014] Further, an enlarged-diameter adjustment shaft flange is provided at the inner end of the adjustment shaft. The adjustment shaft flange is embedded on the inner step at the outer end of the buffer sleeve and is in clearance fit with the inner hole of the buffer sleeve. An annular gap is provided between the outer periphery of the buffer sleeve and the inner step hole of the side cover, and a discharge hole is provided in the middle section of the buffer sleeve and communicates with the annular gap.

[0015] Further, a shaft seal is embedded on the inner wall of the central hole of the side cover to seal the outer periphery of the adjustment shaft.

[0016] Further, an adjustment shaft cap is screwed onto the outer periphery of the outer end of the adjustment shaft. The outer port of the adjustment shaft cap abuts against the inner side of the inner step of the protective cover, and the outer periphery of the adjustment shaft cap is in clearance fit with the inner hole of the protective cover.

[0017] Further, an adjustment shaft screw hole is provided at the center of the outer end of the adjustment shaft. An adjustment screw rod is screwed into the adjustment shaft screw hole. The middle section of the adjustment screw rod is supported by a bearing in the outer port of the protective cover and is axially fixed. The outer end of the adjustment screw rod passes through the central hole of the lock nut and is provided with a square tenon or a hexagonal head, and the lock nut is screwed onto the outer end of the protective cover.

[0018] Further, a locking screw is screwed onto the circumference of the lock nut, and the inner end of the locking screw abuts against the outer wall of the adjustment screw rod.

[0019] Further, a flange integrally connected therewith is provided at the lower port of the alarm device body, and an internal thread interface is provided at the upper end of the alarm device body.

[0020] Further, alarm switch brackets are respectively fixed on the outer periphery of the protective cover, and alarm switches corresponding to the outer ends of the alarm signal rods are respectively fixed at the free ends of the alarm switch brackets.

[0021] Further, the alarm switch is a travel switch or a proximity switch, and the normally open contact of the alarm switch is connected in series in the control circuit of the alarm horn.

[0022] Compared with the prior art, the present utility model has achieved the following beneficial effects: 1. The device mainly consists of an in-cavity detection mechanical alarm system. The in-cavity detection system is a contact-type collar detection tool. The detection rollers are made of wear-resistant materials, and the two side collar detection wheels are of a "V" type structure. The radian is consistent with the oil pipe body, and they fit and roll, with small friction, not easily damaged, and having a function of straightening and centering the oil pipe; a semi-closed gate structure is adopted for symmetrical detection on the left and right to meet the anti-deviation requirement;

[0023] 2. The mechanical force alarm method is adopted to improve the success rate and reliability. The telescopic indicating rod is used as the signal sending structure, which is convenient for the wellhead operator to directly observe. At the same time, the signal sending signal controls the alarm explosion-proof electric horn to sound, realizing double alarm;

[0024] 3. The overall internal detection mechanism can be fully opened, retracted into the inner cavity, maintaining the original upper and lower internal diameters, without affecting the passage of large-diameter tools in the well.

[0025] 4. The two alarm signal rods on each side of the detection mechanism are convenient for the operator to directly observe. They can also cooperate with the alarm probes to remotely judge according to the movement situation in the monitoring operation room, and combined with the sound and light alarm, the detection success rate reaches 100%.

[0026] 4. This device is of mechanical structure, with high reliability, practicability and low maintenance cost. Through on-site trial, it is proved that it is easy to install, has simple operation and reliable effect, and is deeply welcomed by the downhole operation site. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings. The drawings are only for reference and explanation, and are not used to limit the present invention. Among them:

[0028] Figure 1 is the front view of the tubing coupling detection and alarm device of the present invention;

[0029] Figure 2 is Figure 1 the half-sectional view of;

[0030] Figure 3 is the working state diagram of the tubing coupling detection and alarm device of the present invention;

[0031] Figure 4 is the open state diagram of the tubing coupling detection and alarm device of the present invention;

[0032] Figure 5 is the installation state diagram of the present invention at the wellhead;

[0033] In the figure: 1. Adjusting screw rod; 2. Locking nut; 3. Alarm switch bracket; 4. Alarm switch; 5. Alarm signal rod; 6. Side cover; 7. Alarm device body; 8. Coupling detection wheel; 9. Wheel shaft; 10. Detection gate; 11. Buffer sleeve; 12. Buffer spring; 13. Adjusting shaft; 14. Adjusting shaft cap; 15. Protective cover; 16. Locking screw; 17. Alarm horn; 18. Tubing.

[0034] 19. Full blowout preventer; 20. Spare half blowout preventer; 21. Safety slips; 22. Lower half blowout preventer; 23. Balanced four-way; 24. Hydraulic flat valve; 25. Upper half blowout preventer; 26. Annular blowout preventer; 27. Fixed slips; 28. Top self-sealing; 29. Movable slips; 30. Support column; 31. Cross beam; 32. Lifting cylinder. Detailed implementation manners

[0035] In the following description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating that the device must have a specific orientation.

[0036] In order to make the technical means, creative features, achieved purposes and functions of the present invention easy to understand, the present invention will be further described below in conjunction with specific drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0038] As Figures 1 to 4 shown, the tubing coupling detection and alarm device of the present invention includes an alarm device body 7 that penetrates vertically. A flange is provided at the lower end of the alarm device body 7, and a flange is integrally connected to the lower port of the alarm device body 7. An internal thread interface is provided at the upper end of the alarm device body 7, and a flange nipple is screwed into the internal thread interface, that is, the lower end is an external thread joint and the upper end is a flange, so as to reduce the overall height of the alarm device.

[0039] Detection gates 10 are symmetrically arranged in the inner cavity of the alarm device body 7. Openings facing each other are respectively provided in the middle of the opposite ends of the two detection gates 10, and rotatable coupling detection wheels 8 are respectively installed in the two gate grooves. V-shaped grooves are respectively provided in the middle of the outer circumferences of the two coupling detection wheels 8, and a hoisting and lowering channel for the tubing 18 to pass through is formed between the V-shaped grooves of the two coupling detection wheels 8. Side covers 6 are respectively fixed at the two side ports of the alarm device body 7. Alarm signal rods 5 are symmetrically connected to the side of the detection gate 10 close to the side cover 6, and the middle parts of the alarm signal rods 5 respectively extend out from the guiding holes of the side cover 6.

[0040] The outer diameter of the tubing 18 is 73 mm. The tubings 18 are connected to each other through couplings. The outer diameter of the couplings is 89 mm. When the tubing moves upward, the coupling detection wheels 8 on both sides abut against both sides of the tubing. The V-shaped grooves on the left and right sides support both sides of the tubing. With four-point support and a straightening effect, it is convenient for the coupling detection wheels 8 on both sides to translate symmetrically. When the coupling moves upward and contacts the coupling detection wheels 8, while the coupling detection wheels 8 roll, they squeeze the coupling detection wheels 8 on both sides, causing the coupling detection wheels 8 on both sides to be forced to retract simultaneously, driving the detection gate 10 to move away from the axis of the tubing. The detection gate 10 drives the alarm signal rod 5 to extend outward. Since the upward speed of the tubing is relatively slow, when the wellhead operator observes the outer end of the alarm signal rod 5 extending out, they can pause lifting the tubing, or perform operations to avoid the coupling while slowly lifting the tubing, so as to avoid damaging the gate of the blowout preventer.

[0041] Both ends of the central hole of the coupling detection wheel 8 are respectively supported in the middle of the wheel shaft 9 through bearings. Both ends of the wheel shaft 9 are respectively inserted into the shaft holes of the detection gate 10. The shaft holes penetrate the width direction of the detection gate 10. The left and right wheel shafts 9 are parallel to each other. The two coupling detection wheels 8 can respectively roll freely around the wheel shaft 9, reducing the contact force when encountering a coupling.

[0042] A buffer sleeve 11 is fixedly connected to the center of the side of the detection gate 10 facing the side cover 6. The inner end of the buffer sleeve 11 is embedded in the central counterbore of the detection gate 10 to achieve accurate central positioning. A flange is provided on the outer periphery of the inner end of the buffer sleeve 11. Through holes are evenly provided along the circumference of the flange. Each screw passes through the corresponding through hole and is screwed into the threaded hole of the detection gate 10 to fix the buffer sleeve 11.

[0043] A buffer spring 12 is placed in the inner cavity of the buffer sleeve 11. The centers of the outer end faces of the two side covers 6 are respectively fixed with a protective cover 15. An adjusting shaft 13 is respectively provided in the protective cover 15; the inner ends of the buffer spring 12 respectively abut against the centers of the outer end faces of the corresponding detection gates 10, and the outer ends of the buffer spring 12 respectively abut against the inner end faces of the adjusting shafts 13.

[0044] The tension of the buffer spring 12 causes the V-shaped grooves of the coupling detection wheels 8 to maintain a certain contact force on the tubing. When the tubing coupling contacts the coupling detection wheels 8 and the coupling detection wheels 8 are forced to yield, the detection gate 10 translates outward and compresses the buffer spring 12; when the coupling passes over this device, the buffer spring 12 extends to reset the detection gate 10, causing the coupling detection wheels 8 to resume holding both sides of the tubing.

[0045] A counterbore is provided at the center of the inner end face of the detection gate 10, as Figure 4 shown. When the outer end of the buffer sleeve 11 is embedded in the central counterbore of the inner end face of the detection gate 10, the opening between the two coupling detection wheels 8 reaches the maximum, making the passage reach the same 186 mm diameter as the wellhead blowout preventer group, facilitating the entry of other tools or instruments into the well.

[0046] The inner end of the adjusting shaft 13 is provided with an adjusting shaft flange with an enlarged diameter. The adjusting shaft flange is embedded in the inner step at the outer end of the buffer sleeve 11. At this time, the buffer spring 12 is in the maximum elongation state and the adjusting shaft 13 is prevented from being disengaged from the buffer sleeve 11. The adjusting shaft flange is in clearance fit with the inner hole of the buffer sleeve 11, so that the adjusting shaft flange can slide in the inner cavity of the buffer sleeve 11 to compress the buffer spring 12.

[0047] There is an annular gap between the outer periphery of the buffer sleeve 11 and the inner step hole of the side cover 6. A discharge hole is provided in the middle section of the buffer sleeve 11 and communicates with the annular gap to prevent pressure buildup when the adjusting shaft flange compresses the buffer spring 12.

[0048] A shaft seal device is embedded in the inner wall of the central hole of the side cover 6. The shaft seal device holds the outer periphery of the adjusting shaft 13, and the adjusting shaft 13 always maintains a sealed state when translating in the central hole of the side cover.

[0049] An adjusting shaft cap 14 is screwed on the outer periphery of the outer end of the adjusting shaft 13. The outer port of the adjusting shaft cap 14 abuts against the inner side of the inner step of the protective cover 15. The outer periphery of the adjusting shaft cap 14 is in clearance fit with the inner hole of the protective cover 15, which not only enables the adjusting shaft cap 14 to slide along the inner wall of the protective cover 15, but also plays a guiding role. The inner step of the protective cover 15 limits the maximum stroke of the adjusting shaft 13.

[0050] The center of the outer end of the adjusting shaft 13 is provided with an adjusting shaft screw hole. An adjusting screw rod 1 is screwed in the adjusting shaft screw hole. The middle section of the adjusting screw rod 1 is supported in the outer port of the protective cover 15 by two bearings. The two bearings are respectively located on both sides of the adjusting screw rod convex ring. A lock nut 2 is screwed on the outer end of the protective cover 15 and presses on the outer side of the bearing to axially position the adjusting screw rod 1 and enable it to rotate.

[0051] The outer end of the adjusting screw rod 1 passes through the central hole of the lock nut 2 and is provided with a square tenon or a hexagon head. By rotating the adjusting screw rod 1 through the square tenon or the hexagon head, since the adjusting screw rod 1 is axially positioned, the external thread section of the adjusting screw rod 1 pulls the adjusting shaft 13 to translate along its own axis to adjust the opening size between the two collar detection wheels 8.

[0052] A locking screw 16 is screwed on the circumference of the lock nut 2. When the adjusting screw rod 1 is adjusted in place, the locking screw 16 is tightened so that its inner end abuts against the outer wall of the adjusting screw rod 1 to fix the adjusting screw rod 1 and prevent it from rotating after multiple operations.

[0053] Alarm switch brackets 3 are respectively fixed on the outer periphery of the protective cover 15. Alarm switches 4 corresponding to the outer ends of the alarm signal rods 5 are respectively fixed at the free ends of the alarm switch brackets 3. The alarm switch 4 is a travel switch or a proximity switch, and the normally open contact of the alarm switch 4 is connected in series in the control circuit of the alarm horn 17.

[0054] The outer end of the alarm signal rod 5 extends out, not only allowing the operator to directly observe, but also triggering the alarm switch 4 to act, closing the normally open alarm contact, connecting the control circuit of the alarm horn 17 to make the alarm horn 17 sound. The alarm horn 17 uses an explosion-proof electric horn for alarms.

[0055] As Figure 5 shown, a full-closed blowout preventer 19, a spare half-closed blowout preventer 20, a safety slip 21, a lower half-closed blowout preventer 22, a balance cross 23, an upper half-closed blowout preventer 25, an annular blowout preventer 26, a fixed slip 27, and a top self-sealing device 28 are successively installed above the wellhead four-way. A movable slip 29 is located above the top self-sealing device 28. Support columns 30 are respectively arranged on both sides of the wellhead. The support columns 30 are connected by several cross beams 31. A lifting cylinder 32 is located between the support columns 30 and the wellhead tools and is used to lift the wellhead blowout preventer group during installation.

[0056] Hydraulic flat valves 24 are respectively installed on both sides of the balance cross 23. During installation, the coupling alarm device is installed under the lower half-closed blowout preventer 22 in the wellhead blowout preventer group. After installing the coupling alarm device; when the lower half-closed blowout preventer 22 is in a state of sealing and clamping the oil pipe; at the same time, adjust the adjusting screw rod 1 of the coupling alarm device, and after the coupling detection wheel 8 contacts the oil pipe, turn it back 1 / 5 of a turn; and lock the locking screw 16 to lock the adjusting screw rod 1.

[0057] During the process of pulling out the oil pipe, after the oil pipe coupling contacts the coupling detection wheel 8, the coupling detection wheel 8 will move outward, pushing the coupling detection gate 10 and the alarm signal rod 5 to also move outward, triggering the alarm switch 4, connecting the circuits of the two explosion-proof electric horns for alarms, and the explosion-proof electric horns for alarms sound. The two explosion-proof electric horns for alarms are installed at the operator's hand according to the on-site requirements.

[0058] The coupling detection wheels 8 on both sides are of a "V" type structure and have the function of straightening the oil pipe; the connection between the detection gate 10 and the adjusting shaft 13 is a buffer type and is equipped with a buffer spring 12, thereby ensuring the effectiveness of coupling detection.

[0059] When the lower half-closed blowout preventer 22 is opened, the upper half-closed blowout preventer 25 is in a closed state; when the coupling passes over the lower half-closed blowout preventer 22, the lower half-closed blowout preventer 22 is closed, and when the coupling reaches the upper half-closed blowout preventer 25, it is opened, thus reducing the wellhead overflow.

[0060] The above are only the preferred and feasible embodiments of the present utility model, which illustrate and describe the basic principles, main features and advantages of the present utility model. However, the patent protection scope of the present utility model is not limited thereby. Those skilled in the art should understand that the present utility model is not restricted by the above embodiments. Except for the above embodiments, without departing from the spirit and scope of the present utility model, the present utility model may have other implementation manners. The present utility model will also have various changes and improvements. Any technical solutions formed by equivalent substitution or equivalent transformation shall fall within the protection scope required by the present utility model. The protection scope required by the present utility model is defined by the appended claims and their equivalents. The technical features not described in the present utility model can be realized by or adopt the prior art, and will not be elaborated herein.

Claims

1. An oil pipe coupling detection and alarm device, comprising an alarm device body that penetrates vertically, and is characterized in that: The inner cavity of the alarm device body is symmetrically provided with detection gate plates. In the middle of the facing ends of the two detection gate plates, gate plate grooves are respectively provided. Rotatable coupling detection wheels are respectively installed in the two gate plate grooves. In the middle of the outer circumferences of the two coupling detection wheels, V-shaped grooves are respectively provided. A tripping channel for the oil pipe to pass through is formed between the V-shaped grooves of the two coupling detection wheels. Side covers are respectively fixed at the two side ports of the alarm device body. Alarm signal rods are symmetrically connected to one side of the detection gate plate close to the side cover. The middle parts of the alarm signal rods respectively extend out from the guiding holes of the side cover.

2. The tubing coupling detection and alarm device according to claim 1, characterized in that: Both ends of the central hole of the coupling detection wheel are respectively supported in the middle of the wheel shaft through bearings. Both ends of the wheel shaft are respectively inserted into the shaft holes of the detection gate plate.

3. The tubing coupling detection and alarm device according to claim 1, characterized in that: A buffer sleeve is fixedly connected to the center of one side of the detection gate plate facing the side cover. A sink is provided at the center of the inner end face of the detection gate plate for the outer end of the buffer sleeve to be embedded. The outer end of the buffer sleeve is embedded in the inner stepped hole of the corresponding side cover. A buffer spring is arranged in the inner cavity of the buffer sleeve.

4. The tubing coupling detection and alarm device according to claim 3, wherein: Protective covers are respectively fixed at the centers of the outer end faces of the two side covers. Adjusting shafts are respectively arranged in the protective covers. The inner ends of the buffer springs respectively abut against the centers of the outer end faces of the corresponding detection gate plates. The outer ends of the buffer springs respectively abut against the inner end faces of the adjusting shafts.

5. The tubing coupling detection and alarm device according to claim 4, wherein: The inner end of the adjusting shaft is provided with an enlarged adjusting shaft flange. The adjusting shaft flange is embedded on the inner stepped portion of the outer end of the buffer sleeve and is in clearance fit with the inner hole of the buffer sleeve. An annular gap is provided between the outer circumference of the buffer sleeve and the inner stepped hole of the side cover. A discharge hole is provided in the middle section of the buffer sleeve and communicates with the annular gap.

6. The tubing coupling detection and alarm device according to claim 4, characterized in that: A shaft seal is embedded on the inner wall of the central hole of the side cover to seal with the outer circumference of the adjusting shaft.

7. The tubing coupling detection and alarm device according to claim 4, characterized in that: An adjusting shaft cap is screwed on the outer circumference of the outer end of the adjusting shaft. The outer port of the adjusting shaft cap abuts against the inner side of the inner step of the protective cover. The outer circumference of the adjusting shaft cap is in clearance fit with the inner hole of the protective cover.

8. The tubing coupling detection and alarm device according to claim 7, wherein: An adjusting shaft screw hole is provided at the center of the outer end of the adjusting shaft. An adjusting screw rod is screwed in the adjusting shaft screw hole. The middle section of the adjusting screw rod is supported in the outer port of the protective cover through a bearing and is axially fixed. The outer end of the adjusting screw rod passes through the central hole of the lock nut and is provided with a square tenon or a hexagon head. The lock nut is screwed on the outer end of the protective cover.

9. The tubing coupling detection and alarm device according to claim 8, characterized in that: A locking screw is screwed on the circumference of the lock nut. The inner end of the locking screw abuts against the outer wall of the adjusting screw rod.

10. The tubing coupling detection and alarm device according to claim 1, characterized in that: A flange integrally connected therewith is provided at the lower port of the alarm device body. An internal thread interface is provided at the upper end of the alarm device body.

11. The tubing coupling detection and alarm device according to claim 4, wherein: Alarm switch brackets are respectively fixed on the outer circumferences of the protective covers. Alarm switches corresponding to the outer ends of the alarm signal rods are respectively fixed at the free ends of the alarm switch brackets.

12. The tubing coupling detection and alarm device according to claim 11, wherein: The alarm switch is a travel switch or a proximity switch. The normally open contact of the alarm switch is connected in series in the control circuit of the alarm horn.

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