Pressure detection assembly for malleable cast iron pipe fitting

Abstract

The utility model relates to a pressure detection assembly for malleable cast iron pipe fittings, and belongs to the technical field of malleable cast iron pipe fitting processing. Comprising a square fixing frame; a downward pressing cylinder is arranged on a top plate of the fixed frame; an upper pressing die is fixedly arranged at the end part of a piston rod of the downward pressing cylinder; a lower pressing die is fixedly arranged on the upper end face of a bottom plate of the fixing frame and comprises a lower fixing plate and a lower pressing die body, a mounting groove is formed in the center of the upper end face of the lower fixing plate, the lower pressing die body is arranged in the mounting groove and comprises a base, and the base is clamped in the mounting groove. A left side bottom plate and a right side bottom plate are fixedly arranged in a V-shaped groove in the upper end of the base, a left side supporting plate is slidably arranged on the left side bottom plate, and a right side supporting plate is slidably arranged on the right side bottom plate. The problem that the cost is too high due to the fact that all pressure detection pressing dies of existing malleable cast iron pipe fittings need to be replaced when flaws occur is solved.

Description

Technical Field

[0001] This utility model belongs to the field of malleable iron pipe fittings processing technology, specifically relating to a pressure testing component for malleable iron pipe fittings. Background Technology

[0002] After malleable iron pipe fittings are manufactured, they need to be tested for defects such as pinholes that could cause leaks. This testing requires clamping and fixing the fitting in place. Current pressure testing methods use two moving molds to hold the fitting in place, then inflate it with air to check for leaks. However, these molds are integrally formed, meaning that even minor defects require replacement to avoid affecting subsequent pressure tests, resulting in excessively high testing costs. Utility Model Content

[0003] This invention overcomes the shortcomings of the prior art by proposing a pressure testing assembly for malleable iron pipe fittings; it solves the problem that the pressure testing molds for malleable iron pipe fittings need to be completely replaced when defects occur, resulting in excessive costs.

[0004] To achieve the above objectives, this utility model is implemented through the following technical solution.

[0005] A pressure testing assembly for malleable iron pipe fittings includes a square fixed frame; a pressure cylinder is provided on the top plate of the fixed frame, and an upper pressure mold is fixedly provided at the end of the piston rod of the pressure cylinder; a lower pressure mold is fixedly provided on the upper surface of the bottom plate of the fixed frame, the lower pressure mold includes a lower fixed plate and a lower pressure mold body, an installation groove is provided at the center of the upper surface of the lower fixed plate, the lower pressure mold body is provided inside the installation groove, the lower pressure mold body includes a base, the base is snapped into the installation groove, a left bottom plate and a right bottom plate are fixedly provided in the V-shaped groove at the upper end of the base respectively, a left support plate is slidably provided on the left bottom plate, and a right support plate is slidably provided on the right bottom plate.

[0006] Furthermore, the piston rod of the pressing cylinder is vertically downward, the cylinder body of the pressing cylinder is fixedly connected to the upper end face of the top plate of the fixed frame, and the piston rod of the pressing cylinder passes vertically downward through the top plate of the fixed frame; a horizontal upper fixing plate is fixedly installed at the end of the piston rod of the pressing cylinder, and the center of the upper end face of the upper fixing plate is fixedly connected to the end of the piston rod of the pressing cylinder.

[0007] Furthermore, two vertical guide rods are symmetrically arranged on the left and right sides of the upper end face of the upper fixed plate, and two left and right symmetrical guide cylinders are arranged on the top plate of the fixed frame. The guide cylinders are provided with guide holes that run vertically through them, and the upper ends of the two guide rods are respectively inserted into the guide holes of the guide cylinders on the same side.

[0008] Furthermore, the upper mold includes a fixed base, a left fixed piece, and a right fixed piece; the fixed base is a square block structure, the upper end face of the fixed base is fixedly connected to the center of the lower end face of the upper fixed plate, and a square fixing groove is symmetrically arranged on the left and right end faces of the fixed base. Both fixing grooves are connected to the lower end face of the fixed base, and two internal threaded holes are provided on the bottom surface of the two fixing grooves.

[0009] Furthermore, the left and right fixing plates are symmetrically arranged in the two fixing slots of the fixing base. Both the left and right fixing plates include a vertical section and an inclined section. The vertical section is located inside the fixing slot and has two countersunk holes. The two countersunk holes on the vertical section correspond to two internal threaded holes on the bottom surface of the fixing slot. Two screws pass through the countersunk holes on the vertical section and are screwed into the internal threaded holes on the bottom surface of the fixing slot.

[0010] Furthermore, the lower edge of the inclined section is inclined towards the inside of the fixed base, and the angle between the inclined section and the vertical section is 135°. A semi-circular locking groove is provided at the center of the lower edge of the inclined section.

[0011] Furthermore, the lower fixing plate is fixed to the upper surface of the bottom plate of the fixing frame, and a square mounting groove is provided at the center of the upper surface of the lower fixing plate. The lower end of the base is a square columnar structure, and the lower end of the base is engaged inside the mounting groove. The lower end surface of the base is in contact with the inner bottom surface of the mounting groove, and the outer side surface of the lower end of the base is in contact with the inner side surface of the mounting groove.

[0012] Furthermore, both the left and right base plates maintain a 45° angle with the horizontal plane, and the left and right base plates are perpendicular to each other. A dovetail block is fixedly installed on the upper surface of both the left and right base plates along the middle of the front-rear direction, with the two dovetail blocks perpendicular to each other and their lower edges fixedly connected. A dovetail groove with both ends through is provided on the lower surface of the left support plate, and a dovetail groove with both ends through is provided on the lower surface of the right support plate. The dovetail block on the left base plate slides into the dovetail groove of the left support plate, and the dovetail block on the right base plate slides into the dovetail groove of the right support plate. The right end face of the left support plate and the left end face of the right support plate are in contact with each other and remain vertical.

[0013] Furthermore, a circular slot is provided at the center of the upper surface of the left and right support plates. A cylindrical rubber block is fixed inside the slot, and the outer end of the rubber block extends beyond the opening of the slot. The outer end of the rubber block is parallel to the upper surface of the left and right support plates.

[0014] Furthermore, a transverse channel is provided inside the left support plate, which is connected to the front end face of the left support plate; a longitudinal channel is provided inside the rubber block of the left support plate, which is connected to the center of the outer end face of the rubber block; one inner end of the transverse channel is connected to one inner end of the longitudinal channel; an air pipe connector is fixedly installed at one outer end of the transverse channel, which is connected to the pressure detection tube. A pressure detection valve is installed on the pressure detection tube, which is connected to the air storage tank. A digital pressure switch is connected to the inside of the pressure detection tube through a pipeline.

[0015] The beneficial effects of this utility model compared to the prior art are as follows:

[0016] (1) The pressure testing assembly for malleable iron pipe fittings provided by this utility model is designed with the lower pressure mold as a partially replaceable structure. When the left or right support plate is defective, it can be replaced separately, while the base and the other support plate are retained, without having to replace the entire lower pressure mold, thereby reducing the cost of using the entire pressure testing assembly.

[0017] (2) The pressure testing component for malleable iron pipes provided by this utility model has a special design for the upper pressure mold. The locking grooves on the left and right fixing plates are semi-circular arcs. Even if the malleable iron pipe is placed at a slightly misaligned angle on the lower pressure mold body, the locking groove can be corrected during the contact process with the malleable iron pipe. This ensures that the posture of the malleable iron pipe meets the requirements during the final pressure test and will not cause air leakage due to the posture problem of the malleable iron pipe, thus affecting the final test result. This ensures the accuracy of the posture of the malleable iron pipe during the pressure test and thus ensures the accuracy of the final pressure test. Attached Figure Description

[0018] The present invention will now be described in further detail with reference to the accompanying drawings:

[0019] Figure 1 This is a front view of the entire utility model;

[0020] Figure 2 This is a three-dimensional schematic diagram of the entire utility model;

[0021] Figure 3 This is a schematic diagram of the connection between the upper pressure die and the malleable iron pipe fitting. Figure 1 ;

[0022] Figure 4 This is a schematic diagram of the connection between the upper pressure die and the malleable iron pipe fitting. Figure 2 ;

[0023] Figure 5 This is a three-dimensional schematic diagram of the pressing die;

[0024] Figure 6 It was an explosion of the lower die. Figure 1;

[0025] Figure 7 It was an explosion of the lower die. Figure 2 ;

[0026] Among them, 1 is the fixed frame, 2 is the lower pressure cylinder, 3 is the upper fixed plate, 4 is the guide rod, 5 is the guide cylinder, 6 is the upper pressure mold, 7 is the lower pressure mold, 8 is the pressure testing tube, 9 is the malleable iron pipe fitting, 10 is the fixed seat, 11 is the left fixed plate, 12 is the right fixed plate, 13 is the vertical section, 14 is the inclined section, 15 is the snap-fit ​​groove, 16 is the lower fixed plate, 17 is the base, 18 is the left bottom plate, 19 is the right bottom plate, 20 is the left support plate, 21 is the right support plate, 22 is the dovetail groove, 23 is the dovetail block, 24 is the rubber block, 25 is the air pipe connector, 26 is the transverse channel, and 27 is the longitudinal channel. Detailed Implementation

[0027] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, this utility model will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it. The technical solution of this utility model will be described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0028] like Figure 1 As shown in Figure 7, this utility model provides a pressure testing assembly for malleable iron pipe fittings, including a square fixing frame 1, with both the front and rear ends of the fixing frame 1 remaining open. A downward pressure cylinder 2 is provided on the top plate of the fixing frame 1, and an upper pressure mold 6 is fixedly provided at the end of the piston rod of the downward pressure cylinder 2; a downward pressure mold 7 is fixedly provided on the upper surface of the bottom plate of the fixing frame 1.

[0029] The piston rod of the downward-pressing cylinder 2 points vertically downwards. The cylinder body of the downward-pressing cylinder 2 is fixedly connected to the upper end face of the top plate of the fixed frame 1. The piston rod of the downward-pressing cylinder 2 passes vertically downwards through the top plate of the fixed frame 1. A horizontal upper fixed plate 3 is fixedly installed at the end of the piston rod of the downward-pressing cylinder 2, and the center of the upper end face of the upper fixed plate 3 is fixedly connected to the end of the piston rod of the downward-pressing cylinder 2. Two vertical guide rods 4 are symmetrically arranged on the left and right sides of the upper end face of the upper fixed plate 3. Two left-right symmetrical guide cylinders 5 are provided on the top plate of the fixed frame 1. The guide cylinders 5 have guide holes that run vertically through them. The upper ends of the two guide rods 4 are respectively inserted into the guide holes of the guide cylinders 5 on the same side. When the piston rod of the downward-pressing cylinder 2 extends or retracts, it drives the upper fixed plate 3 to move up and down inside the fixed frame 1. When the upper fixed plate 3 rises and falls, it drives the two guide rods 4 to slide inside the guide holes, ensuring the stability of the upper fixed plate 3 when it rises and falls.

[0030] The upper mold 6 includes a fixed base 10, a left fixed piece 11, and a right fixed piece 12. The fixed base 10 is a square block structure. The upper end face of the fixed base 10 is fixedly connected to the center of the lower end face of the upper fixed plate 3. A square fixing groove is symmetrically arranged on the left and right end faces of the fixed base 10. Both fixing grooves are connected to the lower end face of the fixed base 10. Two internal threaded holes are provided on the bottom surface of each fixing groove. The left fixed piece 11 and the right fixed piece 12 are symmetrically arranged in the two fixing grooves of the fixed base 10. Both the left fixed piece 11 and the right fixed piece 12 include a vertical section 13 and an inclined section 14. Both the vertical section 13 and the inclined section 14 are square plate structures. The lower edge of the vertical section 13 is fixedly connected to the upper edge of the inclined section 14. The vertical section 13 is located inside the fixing groove, and its upper edge contacts the upper edge of the fixing groove. Two countersunk holes are provided on the vertical section 13, corresponding to two internally threaded holes on the bottom surface of the fixing groove. Two screws pass through the countersunk holes on the vertical section 13 and are screwed into the internally threaded holes on the bottom surface of the fixing groove, thereby fixing the left fixing piece 11 and the right fixing piece 12 to the fixing groove of the fixing seat 10. The lower edge of the inclined section 14 is inclined towards the inside of the fixing seat 10, and the angle between the inclined section 14 and the vertical section 13 is 135°. A semi-circular locking groove 15 is provided at the center of the lower edge of the inclined section 14.

[0031] The lower mold 7 includes a lower fixing plate 16 and a lower mold body. The lower fixing plate 16 is fixed to the upper surface of the bottom plate of the fixing frame 1. A square mounting groove is provided at the center of the upper surface of the lower fixing plate. The lower mold body is disposed inside the mounting groove at the center of the upper surface of the lower fixing plate 16.

[0032] The lower mold body includes a base 17, a left bottom plate 18, a right bottom plate 19, a left support plate 20, and a right support plate 21. The lower end of the base 17 is a square columnar structure, and the lower end of the base 17 is engaged inside the mounting groove. The lower end surface of the base 17 is in contact with the inner bottom surface of the mounting groove, and the outer sides of the lower end of the base 17 are in contact with the inner sides of the mounting groove.

[0033] A V-shaped groove is provided on the upper side of the base 17, which is continuous from front to back, and the included angle of the V-shaped groove is 90°. A left base plate 18 and a right base plate 19 are fixedly installed inside the V-shaped groove. Both the left base plate 18 and the right base plate 19 are at a 45° angle to the horizontal plane. The left base plate 18 and the right base plate 19 are perpendicular to each other, and the lower edge of the left base plate 18 is fixedly connected to the lower edge of the right base plate 19.

[0034] A dovetail block 23 is fixedly installed on the upper surface of the left base plate 18 and the right base plate 19 along the middle part of the front-back direction. The two dovetail blocks 23 are perpendicular to each other, and the lower edges of the two dovetail blocks 23 are fixedly connected to each other.

[0035] A left support plate 20 is slidably connected to the upper surface of the left base plate 18, and a right support plate 21 is slidably connected to the upper surface of the right base plate 19. A dovetail groove 22, with both ends passing through, is provided on the lower surface of the left support plate 20 and the right support plate 21. A dovetail block 23 on the left base plate 18 is slidably inserted into the dovetail groove 22 of the left support plate 20, and a dovetail block 23 on the right base plate 19 is slidably inserted into the dovetail groove 22 of the right support plate 21. The right end face of the left support plate 20 and the left end face of the right support plate 21 are in contact with each other and remain vertical.

[0036] A circular slot is provided at the center of the upper surface of the left support plate 20 and the right support plate 21. A cylindrical rubber block 24 is fixed inside the slot. The outer end face of the rubber block 24 extends beyond the opening of the slot and is parallel to the upper surface of the left support plate 20 and the right support plate 21.

[0037] A transverse channel 26 is provided inside the left support plate 20, and the transverse channel 26 is connected to the front end face of the left support plate 20. A longitudinal channel 27 is provided inside the rubber block 24 of the left support plate 20, and the longitudinal channel 27 is connected to the center of the outer end face of the rubber block 24. One inner end of the transverse channel 26 is connected to one inner end of the longitudinal channel 27. An air pipe connector 25 is fixedly installed at one outer end of the transverse channel 26, and is connected to the pressure detection tube 8 through the air pipe connector 25. The pressure detection tube 8 is equipped with a pressure detection valve and is connected to the air storage tank. A digital pressure switch is connected to the inside of the pressure detection tube 8 through a pipeline, and the pressure value inside the pressure detection tube 8 is detected by the digital pressure switch.

[0038] The working principle of this utility model is as follows:

[0039] Before testing, the left support plate 20 and the right support plate 21 are first installed on the left base plate 18 and the right base plate 19, respectively. The dovetail groove 22 and the dovetail block 23 ensure the fitting accuracy between the support plate and the base plate, and also facilitate assembly. The pressure testing tube 8 is then connected to the air pipe connector 25 on the left support plate 20.

[0040] Before testing, the lower cylinder 2 is in a retracted state, placing the malleable iron pipe 9 on the lower mold body, so that the two pipe openings of the malleable iron pipe 9 are in contact with the rubber blocks 24 on the left support plate 20 and the right support plate 21. The two rubber blocks 24 seal the two pipe openings of the malleable iron pipe 9, ensuring that the outer end of the longitudinal channel 27 inside the rubber block 24 on the left support plate 20 is located inside the pipe opening of the malleable iron pipe 9.

[0041] Then, the piston rod of the lower cylinder 2 extends, controlling the upper mold 6 to descend. The left fixing plate 11 and the right fixing plate 12 of the upper mold 6 descend synchronously, and the locking grooves 15 on the left fixing plate 11 and the right fixing plate 12 gradually engage with the two perpendicular outer sections of the malleable iron pipe fitting 9. Since the locking grooves 15 on the left fixing plate 11 and the right fixing plate 12 are semi-circular arcs, even if the malleable iron pipe fitting 9 is slightly misaligned on the lower mold body, the locking grooves 15 can be corrected during contact with the malleable iron pipe fitting 9, ensuring that the malleable iron pipe fitting 9 meets the requirements in posture during the final pressure test, and will not cause air leakage due to the posture problem of the malleable iron pipe fitting 9, thus affecting the final test results.

[0042] When the lower pressure cylinder 2 is fully extended, the upper pressure mold 6 and the lower pressure mold body completely clamp the malleable iron pipe 9, and the two pipe openings of the malleable iron pipe 9 are completely sealed by the rubber blocks 24 on the left support plate 20 and the right support plate 21 of the lower pressure mold body.

[0043] Then, the pressure detection valve is opened, and compressed air is introduced into the pipe fitting through the air tank and pressure detection pipe 8, so that the inside of the malleable iron pipe fitting 9 is at a set air pressure value. The pressure value inside the malleable iron pipe fitting 9 is monitored by a digital display pressure switch. If the malleable iron pipe fitting 9 has defects such as sand holes, air leakage will occur, causing the air pressure value inside the malleable iron pipe fitting 9 to drop and fail to maintain the set value. In this case, the digital display pressure switch will detect the change in the air pressure value inside the malleable iron pipe fitting 9 and transmit the change signal to the controller. The controller can then determine that the current malleable iron pipe fitting 9 is a defective product. If the malleable iron pipe fitting 9 does not have defects such as sand holes, there will be no air leakage inside the malleable iron pipe fitting 9, and the air pressure value inside the malleable iron pipe fitting 9 will remain at the set value. When the digital display pressure switch detects that the air pressure value inside the malleable iron pipe fitting 9 has not changed within a set time period, it will output a no-change signal to the controller, and the controller can then determine that the current malleable iron pipe fitting 9 is a qualified product.

[0044] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A pressure testing assembly for malleable iron pipe fittings, characterized in that: The frame includes a square fixed frame (1); a lower pressure cylinder (2) is provided on the top plate of the fixed frame (1), and an upper pressure mold (6) is fixedly provided at the piston rod end of the lower pressure cylinder (2); a lower pressure mold (7) is fixedly provided on the upper surface of the bottom plate of the fixed frame (1). The lower pressure mold includes a lower fixed plate (16) and a lower pressure mold body. An installation groove is provided at the center of the upper surface of the lower fixed plate (16). The lower pressure mold body is provided inside the installation groove. The lower pressure mold body includes a base (17). The base (17) is snapped into the installation groove. A left bottom plate (18) and a right bottom plate (19) are fixedly provided in the V-shaped groove at the upper end of the base (17). A left support plate (20) is slidably provided on the left bottom plate (18), and a right support plate (21) is slidably provided on the right bottom plate (19).

2. A pressure testing assembly for malleable iron pipe fittings according to claim 1, characterized in that: The piston rod of the pressing cylinder (2) is vertically downward, and the cylinder body of the pressing cylinder (2) is fixedly connected to the upper surface of the top plate of the fixed frame (1). The piston rod of the pressing cylinder (2) passes vertically downward through the top plate of the fixed frame (1). A horizontal upper fixed plate (3) is fixedly installed at the end of the piston rod of the pressing cylinder (2). The center of the upper surface of the upper fixed plate (3) is fixedly connected to the end of the piston rod of the pressing cylinder (2).

3. A pressure testing assembly for malleable iron pipe fittings according to claim 2, characterized in that: Two vertical guide rods (4) are symmetrically arranged on the left and right sides of the upper end face of the upper fixed plate (3). Two left and right symmetrical guide cylinders (5) are arranged on the top plate of the fixed frame (1). The guide cylinders (5) are provided with guide holes that run through the top and bottom. The upper ends of the two guide rods (4) are respectively inserted into the guide holes of the guide cylinders (5) on the same side.

4. A pressure testing assembly for malleable iron pipe fittings according to claim 2, characterized in that: The upper mold (6) includes a fixed base (10), a left fixed piece (11), and a right fixed piece (12). The fixed base (10) is a square block structure. The upper end face of the fixed base (10) is fixedly connected to the center of the lower end face of the upper fixed plate (3). A square fixing groove is symmetrically provided on the left and right end faces of the fixed base (10). Both fixing grooves are connected to the lower end face of the fixed base (10). Two internal threaded holes are provided on the bottom surface of the two fixing grooves.

5. A pressure testing assembly for malleable iron pipe fittings according to claim 4, characterized in that: The left fixing plate (11) and the right fixing plate (12) are symmetrically arranged in the two fixing slots of the fixing base (10). The left fixing plate (11) and the right fixing plate (12) both include a vertical section (13) and an inclined section (14). The vertical section (13) is located inside the fixing slot. Two countersunk holes are provided on the vertical section (13). The two countersunk holes on the vertical section (13) correspond to the two internal threaded holes at the bottom surface of the fixing slot. Two screws pass through the countersunk holes on the vertical section (13) and are screwed into the internal threaded holes at the bottom surface of the fixing slot.

6. A pressure testing assembly for malleable iron pipe fittings according to claim 5, characterized in that: The lower edge of the inclined section (14) is inclined towards the inside of the fixed seat (10), and the angle between the inclined section (14) and the vertical section (13) is 135°. A semi-circular snap-fit ​​groove (15) is provided at the center of the lower edge of the inclined section (14).

7. A pressure testing assembly for malleable iron pipe fittings according to claim 1, characterized in that: The lower fixing plate (16) is fixed to the upper surface of the bottom plate of the fixing frame (1). A square mounting groove is provided at the center of the upper surface of the lower fixing plate. The lower end of the base (17) is a square column structure. The lower end of the base (17) is engaged in the inside of the mounting groove. The lower end surface of the base (17) is in contact with the inner bottom surface of the mounting groove. The outer side surface of the lower end of the base (17) is in contact with the inner side surface of the mounting groove.

8. A pressure testing assembly for malleable iron pipe fittings according to claim 7, characterized in that: The left base plate (18) and the right base plate (19) are both at a 45° angle to the horizontal plane, and the left base plate (18) and the right base plate (19) are perpendicular to each other; a dovetail block (23) is fixedly installed on the upper end face of the left base plate (18) and the right base plate (19) along the middle part of the front-back direction, the two dovetail blocks (23) are perpendicular to each other, and the lower edges of the two dovetail blocks (23) are fixedly connected to each other; a dovetail groove with both ends through is provided on the lower end face of the left support plate (20). (22) A dovetail groove (22) with both ends through is provided at the lower end face of the right support plate (21). The dovetail block (23) on the left bottom plate (18) is slidably inserted into the dovetail groove (22) of the left support plate (20). The dovetail block (23) on the right bottom plate (19) is slidably inserted into the dovetail groove (22) of the right support plate (21). The right end face of the left support plate (20) and the left end face of the right support plate (21) are in contact with each other and both remain vertical.

9. A pressure testing assembly for malleable iron pipe fittings according to claim 8, characterized in that: A circular slot is provided at the center of the upper surface of the left support plate (20) and the right support plate (21). A cylindrical rubber block (24) is fixed inside the slot. The outer end face of the rubber block (24) extends beyond the opening of the slot. The outer end face of the rubber block (24) is parallel to the upper surface of the left support plate (20) and the right support plate (21).

10. A pressure testing assembly for malleable iron pipe fittings according to claim 9, characterized in that: A transverse channel (26) is provided inside the left support plate (20), and the transverse channel (26) is connected to the front end face of the left support plate (20); a longitudinal channel (27) is provided inside the rubber block (24) of the left support plate (20), and the longitudinal channel (27) is connected to the center of the outer end face of the rubber block (24); one inner end of the transverse channel (26) is connected to one inner end of the longitudinal channel (27); a tracheal connector (25) is fixedly provided at one outer end of the transverse channel (26), and is connected to the pressure detection tube (8) through the tracheal connector (25). A pressure detection valve is provided on the pressure detection tube (8), and the pressure detection tube (8) is connected to the gas storage tank. A digital pressure switch is connected to the inside of the pressure detection tube (8) through a pipeline.

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