Auxiliary excitation device for drilling jar

Abstract

The present invention provides a drilling jar auxiliary excitation device, comprising: three layers from the inside to the outside, namely a mandrel assembly, an inner cylinder, and an outer cylinder; wherein the mandrel assembly and the inner cylinder are both provided with a plurality of pressure transmission holes for a drilling mud pump to pump mud into the drilling tool water hole to generate pressure; a longitudinal inner gap is provided between the mandrel assembly and the inner cylinder, and the inner gap forms a pressure transmission channel between the mandrel assembly and the inner cylinder; a longitudinal outer gap is provided between the inner cylinder and the outer cylinder, and the outer gap forms a pressure transmission channel between the inner cylinder and the outer cylinder. Through this device, the jar can be activated in a short time when the drill is stuck, so as to release the stuck drill.

Description

Technical Field

[0001] The invention relates to the technical field of drilling, and in particular to an auxiliary excitation device for a drilling jar. Background Art

[0002] In actual application, the drilling jar cannot work 100%, and in large displacement wells and wells with complex borehole conditions, the jar cannot work, which greatly increases the risk of drilling tool stuck. There are two reasons for the failure to work. The first is due to wellbore problems (wellbore collapse or excessive rock debris causing sand bridge stuck). When the drilling tool is lifted and lowered, the tension given by the drilling rig mainly overcomes the resistance of the wellbore, and the axial force transmitted to the jar cannot make the jar work; the second point is that when the stuck point is above the jar, the axial tension or pressure applied by the drilling rig cannot be transmitted to the jar, so it cannot work. Summary of the invention

[0003] The purpose of the present invention is to solve the defects of the above-mentioned prior art and provide a drilling jar auxiliary excitation device. When the drill bit is stuck, the device can operate normally and the jar cannot work. Then, the jar is given an upward or downward axial force by pump pressure boosting, thereby assisting or directly stimulating the jar to work.

[0004] A drilling jar auxiliary excitation device comprises: three layers from the inside to the outside, namely a mandrel assembly, an inner tube and an outer tube; wherein the mandrel assembly and the inner tube are both provided with a plurality of pressure transmission holes for a drilling mud pump to pump mud into the drilling tool water hole to generate pressure; a longitudinal inner gap is provided between the mandrel assembly and the inner tube, and the inner gap forms a pressure transmission channel between the mandrel assembly and the inner tube; a longitudinal outer gap is provided between the inner tube and the outer tube, and the outer gap forms a pressure transmission channel between the inner tube and the outer tube.

[0005] Further, in the drilling jar auxiliary excitation device as described above, the spindle assembly comprises, from top to bottom, an upper spindle joint, a valve seat spindle, a piston spindle, and a lower spindle which are threadedly connected in sequence;

[0006] The outer circumference of the upper spindle joint is provided with a spline, and the spline cooperates with the spline groove provided on the inner cylinder to transmit torque;

[0007] The valve seat spindle is provided with a valve block, a valve block bracket, a through hole, a shear pin and a stopper;

[0008] The top of the valve block bracket is fixedly connected to the valve block by a C-shaped retaining ring, and the lower end thereof is provided with an annular retaining ring, which is fixed by the shear pin, and a spring is placed in the gap between the valve block bracket and the annular retaining ring;

[0009] The stopper is arranged below the annular stop ring; when the spring is in an uncompressed state, the valve block blocks the through hole, and when the spring is in a compressed state, the through hole is opened;

[0010] The piston spindle is provided with two upper and lower sealing rings, which are tightly attached to the inner wall of the inner cylinder and combined with the inner cylinder to form a piston structure; a pressure transmission hole is distributed on the piston structure, and the pressure transmission hole is arranged on the inner cylinder;

[0011] The lower spindle is provided with a pressure transmission hole, and when the pressure transmission hole is connected with the pressure transmission hole on the inner cylinder, the pressure is released.

[0012] Furthermore, in the auxiliary excitation device for the drilling jar as described above, there are multiple piston spindles, which can be combined with the inner cylinder to form multiple piston structures, and one of the pressure transmission holes is distributed on each piston structure.

[0013] Further, in the auxiliary excitation device for the drilling jar as described above, the inner tube comprises, from top to bottom, an inner tube upper joint, an inner tube valve seat section, an inner tube piston section, an inner tube pressure release section, and an inner tube lower joint which are threadedly connected in sequence;

[0014] The upper joint of the inner cylinder is an irregular annular component, and a spline groove is arranged on its inner circumference to cooperate with the spline to transmit torque; threads are distributed on its outer circumference, and the upper half of the thread is threadedly connected to the upper end of the outer cylinder, and the lower half of the thread is threadedly connected to the upper end of the valve seat section of the inner cylinder;

[0015] A pressure transmission hole is arranged on the inner cylinder valve seat section, and a sealing ring is arranged on the pressure transmission channel formed between the valve seat spindle and the inner cylinder valve seat section, and the sealing ring divides the pressure transmission channel into two upper and lower sealing chambers;

[0016] The inner cylinder piston section is a cylindrical structure with different inner diameters, and is also provided with a pressure transmission hole; the inner cylinder piston section has sealing rings at both ends, and cooperates with the piston spindle to form a piston structure;

[0017] A pressure transmission hole is arranged at the lower part of the inner cylinder pressure release section; the inner cylinder pressure release section cooperates with the lower spindle to form a piston structure;

[0018] The inner tube lower joint is used to connect the outer tube and the lower drilling tool.

[0019] Further, in the auxiliary excitation device for the drilling jar as described above, the outer tube comprises: an outer tube upper joint, an outer tube middle section, an outer tube pressure release section, and an outer tube lower sealing joint;

[0020] The upper half of the outer tube upper joint is threadedly connected to the inner tube upper joint, and the lower half is threadedly connected to the middle section of the outer tube;

[0021] The middle section of the outer cylinder and the inner cylinder together form a pressure transmission channel, and the upper and lower ends of the channel are connected by threads;

[0022] The outer cylinder pressure release section and the inner cylinder pressure release section form a pressure channel, and are threadedly connected at the top and bottom;

[0023] A sealing ring is provided on the sealing joint at the lower part of the outer cylinder, which is used to seal the inner cylinder and the outer cylinder.

[0024] Beneficial effects:

[0025] The auxiliary excitation device for the drilling jar provided by the present invention is mainly used in complex wells and horizontal wells. When there is a high risk of failure and the torque and axial force cannot be transmitted from the wellhead to the jar, the jar can be activated in a short time after the drill is stuck to release the stuck drill. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the auxiliary excitation device of the drilling jar according to the present invention;

[0027] Figure 2 Schematic diagram of the upper spindle joint structure;

[0028] Figure 3 It is a schematic diagram of the valve seat spindle structure;

[0029] Figure 4 It is a schematic diagram of the spindle piston structure;

[0030] Figure 5 It is a schematic diagram of the joint structure on the inner tube;

[0031] Figure 6 It is a schematic diagram of the structure of the inner cylinder valve seat section;

[0032] Figure 7 It is a schematic diagram of the structure of the inner cylinder piston section;

[0033] Figure 8 It is a schematic diagram of the structure of the pressure release section of the inner cylinder;

[0034] Fig. 9 It is a schematic diagram of the structure of the lower joint of the inner tube;

[0035] Fig.10 It is a schematic diagram of the joint structure on the outer tube;

[0036] Fig.11 It is a schematic diagram of the structure of the middle section of the outer cylinder;

[0037] Fig.12 It is a schematic diagram of the structure of the outer cylinder release section;

[0038] Fig.13It is a schematic diagram of the structure of the lower joint of the outer tube; Description of the drawings:

[0040] 1-upper spindle joint, 2-valve seat spindle, 3-piston spindle, 4-lower spindle, 5-inner tube upper joint, 6-inner tube valve seat section, 7-inner tube piston section, 8-inner tube pressure release section, 9-inner tube lower joint, 10-outer tube upper joint, 11-outer tube middle section, 12-outer tube pressure release section, 13-outer tube lower sealing joint, 14-pressure transmission hole, 15-spline, 16-pressure ring, 17-valve block, 18-valve block bracket, 19-through hole, 20-shear pin, 21-stopper, 22-seal ring 1, 23-seal ring 2, 24-spline groove. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] like Figure 1 As shown, the drilling jar auxiliary excitation device provided by the present invention is composed of three layers from the inside to the outside, namely a core shaft assembly-an inner cylinder-an outer cylinder, and the inner cylinder and the outer cylinder are connected together.

[0043] The spindle assembly includes: an upper spindle joint 1, a valve seat spindle 2, a piston spindle 3, and a lower spindle 4; the upper spindle joint 1, the valve seat spindle 2, the piston spindle 3, and the lower spindle 4 are connected in sequence by threaded connection. The inner tube includes: an inner tube upper joint 5, an inner tube valve seat section 6, an inner tube piston section 7, an inner tube pressure release section 8, and an inner tube lower joint 9; the inner tube upper joint 5, the inner tube valve seat section 6, the inner tube piston section 7, the inner tube pressure release section 8, and the inner tube lower joint 9 are all connected in sequence by threads. The outer tube includes: an outer tube upper joint 10, an outer tube middle section 11, an outer tube pressure release section 12, and an outer tube lower sealing joint 13; the outer tube upper joint 10, the outer tube middle section 11, the outer tube pressure release section 12, and the outer tube lower sealing joint 13 are threadedly connected in sequence, and the outer tube upper section head 10 is threadedly connected to the outer side of the inner tube upper joint 5. A longitudinal gap is provided between the spindle assembly and the inner cylinder, and the gap forms a pressure transmission channel between the spindle assembly and the inner cylinder, and a plurality of pressure transmission holes are distributed on the gap; a longitudinal gap is also provided between the inner cylinder and the outer cylinder, and the gap forms a pressure transmission channel between the inner cylinder and the outer cylinder.

[0044] like Figure 2As shown, the lower end of the upper spindle joint 1 is provided with a spline 15 and a pressure ring 16; the spline 15 is used to transmit the torque between the spindle and the inner tube; the pressure ring 16 is used to transmit the weight of the drill string and is an annular pressure-bearing component with a limiting function.

[0045] like Figure 3 As shown, the valve seat spindle 2 includes: a valve block 17, a valve block bracket 18, a through hole 19, a shear pin 20, and a stopper 21;

[0046] The top of the valve block bracket 18 is fixedly connected to the valve block 17 via a C-shaped retaining ring, and an annular retaining ring is provided at the lower end thereof, and the annular retaining ring is fixed via the shear pin 20, and a spring is placed in the gap between the valve block bracket 18 and the annular retaining ring;

[0047] The stopper 21 is arranged below the annular stop ring; when the spring is in an uncompressed state, the valve block 17 blocks the through hole 19, and when the spring is in a compressed state, the through hole 19 is opened.

[0048] The valve block 17 and the valve block bracket 18 constitute a valve seat; the valve seat spindle 2 is a two-stage reducer, and a shear pin is provided at the bottom to fix the spring base. The device generates pressure by using a drilling mud pump to pump mud into the drilling tool water hole. When the generated pressure is greater than the elastic force of the valve seat spring, the valve seat moves downward, and the mud can flow out of the pressure transmission hole. Specifically, when the iron ball is lowered from the drilling tool water hole to this point, the valve block 17 moves downward, so that the through hole 19 is opened, and the mud flows out from the through hole 19, and the pressure is transmitted from the through hole of the inner tube. The block 21 is used to prevent the valve seat from falling into the lower part after being sheared off.

[0049] Specifically, the shear pin fixes the annular baffle, and the baffle and the valve block bracket 18 are connected by spring support. In the first stage, a large ball is first put in, which can just block the center of the valve seat spindle 2. Then, when the large ball falls to the valve block 17, under the action of the pump pressure, the valve block 17 and the valve block bracket 18 are pushed down together, thereby compressing the spring, the through hole 19 is opened, and the pressure is transmitted to the lower part. When circulation is needed after unblocking, two relatively small iron balls are put in (after the two iron balls fall into the center of the valve seat spindle 2, they can just block the two through holes 19 under the action of pump pressure, and it is necessary to calculate here so that the diameter of the small iron balls put in is 1 / 2 of the inner diameter of the valve seat spindle 2), thereby closing the two through holes 19. When the high pump pressure is continued to be pressurized so that the pressure of the high-pressure pump reaches the preset value, the shear pin 20 is sheared off, and the annular baffle fixed by the shear pin 20 falls off to the block 21. At the same time, the valve block 17 falls to the upper end of the block 21, where the inner diameter is larger than the outer diameter of the valve block 17, so that the mud can pass through the gap between the valve block 17 and the upper end of the block 21, and finally the mud flows through the center of the spindle assembly, thereby achieving the purpose of circulation.

[0050] like Figure 4 As shown, two upper and lower sealing rings are arranged on the piston spindle 3, namely sealing ring 1 22 and sealing ring 2 23; the piston spindle 3 can be connected in series in multiples in the device of the present invention, and the upper and lower connections are API threads. Only one is drawn in this figure.

[0051] like Figure 1 As shown, the main function of the lower mandrel 4 is mandrel movement and pressure release, which can provide continuous axial force. A pressure transmission hole is provided on the lower mandrel 4. When the pressure transmission hole is connected to the pressure transmission hole on the inner cylinder pressure release section 8, the pressure is released.

[0052] like Figure 5 and Figure 1 , Figure 2 As shown, the inner tube upper joint 5 is an irregular annular component, with threads arranged on its outer circumference and spline grooves 24 arranged on its inner circumference for use in conjunction with the splines 15 of the spindle upper joint 1 to transmit torque.

[0053] like Figure 6 As shown, the inner cylinder valve seat section 6 is provided with a pressure transmission hole 14. Figure 3 The valve seat spindle 3 shown is used in combination.

[0054] like Figure 7 As shown, the inner cylinder piston section 7 is a cylindrical structure with different inner diameters, and a pressure transmission hole 14 is also provided on it; the inner cylinder piston section 7 has sealing rings at both ends. Figure 4 The piston spindle 3 shown cooperates to enable the piston to move in a sealed manner.

[0055] like Figure 8 As shown, a pressure transmission hole 14 is also provided at the lower part of the inner cylinder pressure release section 8. The inner cylinder pressure release section 8 cooperates with the lower mandrel 4. When the pressure transmission hole 14 of the inner cylinder pressure section is connected with the pressure transmission hole 14 on the lower mandrel 4, the pressure is released and the tool is reset.

[0056] like Fig. 9 As shown, the inner tube lower joint 9 is used to connect the outer tube and the lower drilling tool. The upper and lower connections are threaded connections.

[0057] like Fig.10 As shown, the outer tube upper joint 10 is used to connect the outer tube and the inner tube, and its upper part is threadedly connected to the inner tube upper joint 5, and its lower part is threadedly connected to the outer tube middle section 11.

[0058] like Fig.11 As shown, the middle section 11 of the outer tube and the inner tube together form a pressure transmission channel for pressure transmission. The upper and lower connections are threaded connections.

[0059] like Fig.12 As shown, the outer cylinder pressure release section 12 and the inner cylinder pressure release section 8 form a pressure channel, which are threadedly connected at the top and bottom.

[0060] like Fig.13 As shown, the sealing joint 13 at the lower part of the outer cylinder is used to seal the inner cylinder and the outer cylinder. The upper part of the connection is a threaded connection, and the body is provided with a sealing ring.

[0061] The working principle of the device provided by the present invention is as follows: because the working principle of the drilling jar is to stretch or compress the internal mechanism of the jar through the change of the axial force of the drill bit, when the critical value of the tension is reached, the locking mechanism of the jar is suddenly released, the striking structure inside the jar collides, causing shock, and the generated vibration wave is transmitted to the stuck point, which finally unblocks the stuck point; the tool is installed at the upper and lower positions of the jar, and during drilling, the torque and drilling pressure can be smoothly transmitted through the upper spindle joint 1, and the spline 15 at the lower part of the upper spindle joint 1 and the corresponding spline groove 24 of the inner tube form a torque transmission device; the lower part of the upper spindle joint 1 is provided with an anti-slip device and a load-bearing ring 16, so that the movement of the upper drilling tool can be smoothly transmitted to the lower drilling tool through the tool.

[0062] The device provides axial tension or pressure to the drill string through the pump pressure provided by the drilling pump, thereby assisting or directly stimulating the drilling jar.

[0063] When it is necessary to provide an upward axial force: an iron ball is inserted to close the valve seat above the mandrel, the water eye of the mandrel is blocked, and the pump pressure is transmitted to each piston through the pressure transmission hole of the inner tube, so that the force on the drill string is upward, causing the mandrel to move upward. When the pump pressure reaches the set value, the pressure relief hole (pressure transmission hole 14) on the mandrel moves upward to connect to the lower water eye, the pressure drops, and the mandrel moves downward again. When the pump pressure rises, the mandrel moves up again, and this is repeated until the jam is released by shock. After the jam is released, the pump pressure is increased to the set value, the valve seat is sheared off, the circulation is resumed, and drilling is started.

[0064] When it is necessary to provide a downward axial force: an iron ball is inserted to close the valve seat below the mandrel, the water eye of the mandrel is blocked, and the pump pressure is transmitted to each piston through the liquid inlet hole (pressure transmission hole 14) of the inner tube, so that the force on the drill string is downward, causing the mandrel to move downward. When the pump pressure reaches the set value, the pressure relief hole on the mandrel moves downward to connect to the lower water eye, the pressure drops, and the mandrel moves upward. When the pump pressure rises, the mandrel moves downward again, and this is repeated until the jam is released by shock. After the jam is released, the pump pressure is increased to the set value, the valve seat is sheared off, the circulation is resumed, and the drilling is started.

[0065] That is, according to the principle of axial force generation, the energy is mainly provided by the drilling mud pump - pump pressure. The pump pressure works with the inner tube and the mandrel, causing the mandrel to move downward, driving the drill tool connected to the inner tube to move upward, generating axial force, so that the jar obtains an upward pulling force. When it is necessary to jar downward, activate the tool lowered by the jar, the pump pressure works with the mandrel and the inner tube, the mandrel moves upward, the inner tube moves downward, and the jar connects to the mandrel, so that the jar obtains a downward pulling force.

[0066] In practical applications, multiple groups of pistons are selected to be connected in series according to the weight and connection method of the drilling tool and the working requirements of the jar to provide sufficient axial force to enable the jar to work.

[0067] The working process of the device provided by the present invention is as follows: the tool is respectively installed above and below the jar, the tool can realize the transmission of the suspended weight and torque of the drill tool, and can be used in the normal drilling process. When the drill tool is stuck, the jar is first used to release the jam through conventional operations. If the jar cannot release the jam normally, the jar needs to be struck up or down according to the actual situation; if the jar is struck up, an iron ball is put in to make the excitation tool above the jar work, and the drilling team's mud pump is used to pressurize so that the iron ball enters through the water hole of the drill tool After the ball seat, the spindle valve seat opens, and the drilling pump continues to be used to pressurize. The pressure is transmitted from the pressure transmission hole to between the valve seat spindle 2 and the inner tube valve seat section 6, and then transmitted to between the inner tube and the outer tube through the inner tube pressure transmission hole 14. The pressure is then transmitted to the upper part of the piston spindle 3 through the pressure transmission hole at the inner tube piston section 7, pushing the spindle downward, and the reaction force acts on the inner tube at the inner tube piston section 7, causing the inner tube to move upward. The inner tube is connected to the jar through the inner tube lower joint 9, so that the jar spindle moves upward to achieve a jarring effect. As the spindle moves downward, when the pressure transmission hole at the lower spindle 4 is connected with the pressure transmission hole at the pressure release section 8 of the inner tube, the pressure drops, the spindle resets, and a stroke is completed; the pump is turned on to increase the pressure again, the pressure rises, and the shock continues; if the drill bit is unstuck and circulation needs to be established, two small iron balls are sent through the drill bit water hole to block the pressure transmission holes on both sides of the ball seat, the pump is turned on to hold the pressure to a fixed value, the ball seat spring seat slides to the bottom of the valve seat spindle 2, the water eye is unblocked, and circulation is established.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drilling jar auxiliary excitation device, characterized in that: include: From the inside to the outside, it includes three layers, namely, the mandrel assembly, the inner cylinder, and the outer cylinder; wherein, the mandrel assembly and the inner cylinder are both provided with a plurality of pressure transmission holes for the drilling mud pump to pump mud into the drilling tool water hole to generate pressure; a longitudinal inner gap is provided between the mandrel assembly and the inner cylinder, and the inner gap constitutes a pressure transmission channel between the mandrel assembly and the inner cylinder; a longitudinal outer gap is provided between the inner cylinder and the outer cylinder, and the outer gap constitutes a pressure transmission channel between the inner cylinder and the outer cylinder; The spindle assembly comprises, from top to bottom, an upper spindle joint (1), a valve seat spindle (2), a piston spindle (3), and a lower spindle (4) which are threadedly connected in sequence; The outer circumference of the upper spindle joint (1) is provided with a spline (15), and the spline (15) cooperates with the spline groove provided on the inner cylinder to transmit torque; The valve seat spindle (2) is provided with a valve block (17), a valve block bracket (18), a through hole (19), a shear pin (20), and a stopper (21); The top end of the valve block bracket (18) is fixedly connected to the valve block (17) via a C-shaped retaining ring, and the lower end thereof is provided with an annular retaining ring, which is fixed by the shear pin (20), and a spring is placed in the gap between the valve block bracket (18) and the annular retaining ring; The stopper (21) is arranged below the annular stopper ring; when the spring is in an uncompressed state, the valve block (17) blocks the through hole (19); when the spring is in a compressed state, the through hole (19) is opened; The piston spindle (3) is provided with two upper and lower sealing rings, which are tightly attached to the inner wall of the inner cylinder and are combined with the inner cylinder to form a piston structure; a pressure transmission hole (14) is distributed on the piston structure and is arranged on the inner cylinder; The lower spindle (4) is provided with a pressure transmission hole, and when the pressure transmission hole is connected with the pressure transmission hole (14) on the inner cylinder, the pressure is released; There are multiple piston spindles (3), which are combined with the inner cylinder to form multiple piston structures, and each piston structure is provided with a pressure transmission hole; The inner tube comprises, from top to bottom, an inner tube upper joint (5), an inner tube valve seat section (6), an inner tube piston section (7), an inner tube pressure release section (8), and an inner tube lower joint (9) which are threadedly connected in sequence; The inner tube upper joint (5) is an irregular annular component, and a spline groove (24) is provided on its inner circumference for cooperating with the spline (15) to transmit torque; threads are distributed on its outer circumference, the upper half of the thread is threadedly connected to the upper end of the outer tube, and the lower half of the thread is threadedly connected to the upper end of the inner tube valve seat section (6); A pressure transmission hole (14) is provided on the inner cylinder valve seat section (6), and a sealing ring is provided on the pressure transmission channel formed between the valve seat core shaft (2) and the inner cylinder valve seat section (6), and the sealing ring divides the pressure transmission channel into two upper and lower sealing chambers; The inner cylinder piston section (7) is a cylindrical structure with different inner diameters, and is also provided with a pressure transmission hole (14); the inner cylinder piston section (7) has sealing rings at both upper and lower ends, and cooperates with the piston spindle (3) to form a piston structure; A pressure transmission hole (14) is provided at the lower part of the inner cylinder pressure release section (8); the inner cylinder pressure release section (8) cooperates with the lower spindle (4) to form a piston structure; The inner tube lower joint (9) is used to connect the outer tube and the lower drilling tool.

2. The drilling jar auxiliary excitation device according to claim 1, characterized in that: The outer cylinder comprises: an outer cylinder upper joint (10), an outer cylinder middle section (11), an outer cylinder pressure release section (12), and an outer cylinder lower sealing joint (13); The upper part of the outer tube upper joint (10) is threadedly connected to the inner tube upper joint (5), and the lower part is threadedly connected to the outer tube middle section (11); The middle section (11) of the outer cylinder and the inner cylinder together form a pressure transmission channel, and the upper and lower ends thereof are both connected by threaded connection; The outer cylinder pressure release section (12) and the inner cylinder pressure release section (8) form a pressure channel, and are threadedly connected at the top and bottom. A sealing ring is provided on the sealing joint (13) at the lower part of the outer cylinder, which is used to seal the inner cylinder and the outer cylinder.

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