CN217384614U

CN217384614U - Pipeline air tightness detection device

Info

Publication number: CN217384614U
Application number: CN202221251704.2U
Authority: CN
Inventors: 杨文贵; 黎文彬; 刘生君
Original assignee: Jiaxing Da Ding Automation Technology Co ltd
Current assignee: Jiaxing Da Ding Automation Technology Co ltd
Priority date: 2022-05-19
Filing date: 2022-05-19
Publication date: 2022-09-06
Anticipated expiration: 2032-05-19

Abstract

The utility model discloses a pipeline air tightness detection device, which comprises a frame, a plurality of differential pressure detection combined isolating valves and a plurality of differential pressure detection sensors, wherein standard pipelines which are in one-to-one correspondence with each pipeline to be detected are fixed on the frame; a plurality of pairs of pipeline end part sealing connection devices are installed on the rack, each pipeline end part sealing unit is used for being in sealing connection with one end of a detected pipeline at a corresponding position, the other pipeline end part sealing unit in each pair of pipeline end part sealing connection devices is connected with a first air outlet channel in a corresponding pressure difference detection combined type isolating valve, the other end of each standard pipeline is connected with a second air outlet channel in a corresponding pressure difference detection combined type isolating valve, and two air inlet ends of each air pressure difference detection sensor are respectively connected with the first air outlet channel and the second air outlet channel in the corresponding pressure difference detection combined type isolating valve; the utility model discloses can carry out automated inspection to the gas tightness of being surveyed the pipeline.

Description

Pipeline air tightness detection device

Technical Field

The utility model relates to an air tightness check out test set technical field, concretely relates to pipeline air tightness check out test set.

Background

After the pipeline production is finished, the air tightness of the pipeline needs to be detected, and the main purpose of the air tightness detection is to detect whether the pipeline leaks; the current method for detecting the air tightness of the pipeline is as follows: firstly, plugging one end of a pipeline to be detected and one end of a standard pipeline, then connecting one sealing joint with the other end of the pipeline to be detected in a sealing way, connecting the other sealing joint with the other end of the standard pipeline in a sealing way, then connecting one sealing joint with the air outlet end of one air valve through one connecting pipe, connecting the other sealing joint with the air outlet end of the other air valve through the other connecting pipe, then connecting the air inlet ends of the two air valves with an air inlet pipe, communicating one air inlet end of an air pressure difference detection sensor with one connecting pipe, communicating the other air inlet end of the air pressure difference detection sensor with the other connecting pipe, electrically connecting the air pressure difference detection sensor with a controller, and opening the two air valves to enable the air inlet pipe to fill compressed air into the pipeline to be detected and the standard pipeline when detection is started, after the inflation is finished, the two air valves are closed, then the air pressure difference detection sensor starts to detect the air pressure difference between one connecting pipe and the other connecting pipe, if the air pressure difference between one connecting pipe and the other connecting pipe is smaller than a preset value, the situation that the detected pipeline does not leak is indicated, and if the air pressure difference between one connecting pipe and the other connecting pipe is larger than the preset value, the situation that the detected pipeline leaks is indicated, so that the air tightness of the detected pipeline is detected; however, in the above detection process, whether the air inflation of the detected pipeline and the standard pipeline is required to be independently controlled through two air valves, so that the defects of complex control and structure exist.

SUMMERY OF THE UTILITY MODEL

To the not enough of prior art, the utility model provides a pipeline gas tightness check out test set, it can simultaneous control to the aerifing and stop aerifing of surveyed pipeline and standard pipeline to have the simple advantage of control, and can simplify pipeline gas tightness check out test set's structure.

The utility model discloses a pipeline air tightness detection device, including frame, a plurality of differential pressure detection combination formula block valve and a plurality of differential pressure detection sensor all with every pipeline one-to-one under test, be fixed with the standard pipeline with every pipeline one-to-one under test in the frame; a plurality of pairs of pipeline end part sealing and connecting devices are arranged on the rack, two pipeline end part sealing units in each pair of pipeline end part sealing and connecting devices are respectively arranged on the rack at the positions of two end parts of the corresponding detected pipeline, each pipeline end part sealing unit is used for being in sealing connection with one end of the detected pipeline at the corresponding position, one pipeline end part sealing unit in each pair of pipeline end part sealing and connecting devices is used for plugging one end of the detected pipeline, the other pipeline end part sealing unit in each pair of pipeline end part sealing and connecting devices is connected with a first air outlet channel in a corresponding pressure difference detection combined isolating valve, one end of each standard pipeline is plugged, the other end of each standard pipeline is connected with a second air outlet channel in the corresponding pressure difference detection combined isolating valve, and two air inlet ends of each air pressure difference detection sensor are respectively connected with the first air outlet channel and the second air outlet channel in the corresponding pressure difference detection combined isolating valve Connecting the channels; in above-mentioned structure, getting to every pipeline under test can adopt independent electro-magnet to adsorb, for example erection bracing frame on the manipulator, the bottom installation and every pipeline under test one-to-one electro-magnet of support frame, when the electro-magnet circular telegram, the electro-magnet can magnetic adsorption by the pipeline under test, when the electro-magnet outage, the electro-magnet can release by the pipeline under test, so, can conveniently realize the removal to the pipeline under test.

The utility model discloses a pipeline air tightness detection device, wherein, each pressure difference detection combined isolating valve comprises a base, a first valve seat, a first cylinder and a first piston; the lower end of the first valve seat is fixed on the base, a first sealing structure is arranged between the lower end of the first valve seat and the base, a cavity is formed between the first valve seat and the base, a first air cylinder is fixed at the upper end of the first valve seat, a first piston is vertically and slidably arranged in the first valve seat in a penetrating manner, the lower end of the first piston extends into the cavity, a second sealing structure is arranged between the first piston and the first valve seat, the upper end of the first piston is connected with the driving end of the first air cylinder, an air inlet channel, a first air outlet channel and a second air outlet channel are arranged in the base, one end of the air inlet channel, one end of the first air outlet channel and one end of the second air outlet channel are communicated with the cavity, the other end of the air inlet channel is used for being connected with an air inlet pipe, and the other end of the first air outlet channel is used for being connected with another pipe end sealing unit in the corresponding pipe end sealing connection device, the other end of the second air outlet channel is used for being connected with the other end of the corresponding standard pipeline, a sealing gasket is embedded at the lower end of the first piston, after the first piston is driven by the first cylinder to move downwards, the sealing gasket is used for abutting against the upper end face of the base and used for sealing one end of the first air outlet channel and one end of the second air outlet channel, a first air vent and a second air vent are further arranged on the base, one end of the first air vent and one end of the second air vent are respectively communicated with the first air outlet channel and the second air outlet channel, the other end of the first air vent is used for being connected with one air inlet end of the corresponding air pressure difference detection sensor, and the other end of the second air vent is used for being connected with the other air inlet end of the corresponding air pressure difference detection sensor; after the differential pressure detection combined type block valve is adopted, the inflation of the detected pipeline and the standard pipeline can be controlled and stopped at the same time.

The pipeline air tightness detection equipment of the utility model is characterized in that the outer edge of one end of the first air outlet channel and the outer edge of one end of the second air outlet channel are both protruded out of the upper end surface of the base; after the outer edge of one end of the first air outlet channel and the outer edge of one end of the second air outlet channel are both arranged to be protruded out of the upper end face of the base, the outer edge of one end of the first air outlet channel and the outer edge of one end of the second air outlet channel can better extrude the sealing gasket after the first piston is driven by the first cylinder to move downwards, and therefore the sealing gasket can more reliably seal one end of the first air outlet channel and one end of the second air outlet channel; the first sealing structure comprises a first sealing ring, an annular boss is arranged on the lower end face of the first valve seat, a first annular groove is arranged on the upper end face of the base, the first sealing ring is embedded in the first annular groove, the annular boss is inserted into the first annular groove and used for pressing the first sealing ring, and the first sealing ring, the first annular groove and the annular boss are tightly attached and sealed; by adopting the first sealing structure, after the first valve seat is assembled on the base, the lower end of the first valve seat and the base can be reliably sealed; the second sealing structure comprises a plurality of second sealing rings distributed along the axial direction of the first piston, first annular caulking grooves corresponding to the second sealing rings one by one are arranged on the outer wall of the first piston, each second sealing ring is embedded in the first annular caulking groove at the corresponding position, and each second sealing ring is tightly attached and sealed with the inner wall of the first valve seat and the first annular caulking groove at the corresponding position; by adopting the second sealing structure, the sealing between the first piston and the first valve seat can be reliably realized; a T-shaped clamping groove is formed in the upper end of the first piston, a T-shaped clamping block is arranged on the driving end of the first cylinder, and the clamping block is matched and clamped with the clamping groove; after adopting this kind of structure, the upper end of first piston can link together with the drive end of first cylinder reliably, and when the drive end of first cylinder contracts, first cylinder can drive first piston and shift up, and when the drive end of first cylinder extended, first cylinder can drive first piston and move down.

The pipeline air tightness detection device of the utility model, wherein, the pressure difference detection combined type isolating valve also comprises a second valve seat, a second cylinder and a second piston, the lower end of the second valve seat is fixed on the base, the second cylinder is fixed with the upper end of the second valve seat, the second piston is vertically slidably arranged in the second valve seat, the upper end of the second piston is fixed with the driving end of the second cylinder, the lower end of the second piston is provided with an inserted bar with the outer diameter smaller than that of the second piston, the outer part of the inserted bar is sleeved with a first sealing ring, a third vent hole is arranged in the base, one end of the third vent hole is communicated with the first air outlet channel, after the second piston is driven by the second cylinder to move downwards, the lower end of the inserted bar is inserted into the other end of the third vent hole, the first sealing ring is used for abutting against the upper end surface of the base and blocking the third vent hole, the side wall of the second valve seat is connected with an exhaust joint, after the second cylinder drives the second piston to move upwards, the exhaust joint is used for being communicated with the third vent hole through the second valve seat; by adopting the structure, after the detected pipeline is detected, when the second cylinder drives the second piston to move upwards, the sealing ring can remove the blockage of the third vent hole, and at the moment, the compressed air filled in the detected pipeline can be discharged through the first air outlet channel, the third vent hole, the second valve seat and the exhaust joint in sequence, so that when the exhaust joint is connected with one end of the air blow pipe and one end of the air blow pipe is arranged in the pipeline end chamfering mechanism, the compressed air blown out by the air blow pipe can blow off metal debris in the pipeline end chamfering mechanism, namely the compressed air is reused, and the purpose of saving energy is achieved; the outer edge of the other end of the third vent hole protrudes out of the upper end face of the base; after adopting this kind of structure, after second cylinder drive second piston moves down, the outward flange of third ventilation hole other end can realize the extrusion to first sealing washer better, so, first sealing washer can realize the shutoff to third ventilation hole better.

The pipeline air tightness detection equipment of the utility model is characterized in that the base is also provided with a fourth vent hole, one end of the fourth vent hole is communicated with the first air outlet channel, and the other end of the fourth vent hole is used for being connected with a barometer; by adopting the structure, the staff can clearly know the real-time air pressure in the first air outlet channel through the air pressure meter.

When the pressure difference detection combined type block valve works, the driving end of the first cylinder drives the first piston to move downwards to enable the first sealing ring to block the third vent hole, then the driving end of the first cylinder drives the first piston to move upwards to enable the sealing gasket to unblock one end of the first air outlet channel and one end of the second air outlet channel, at the moment, compressed air from the air inlet pipe can enter the cavity through the air inlet channel, the compressed air entering the cavity can be filled into the tested pipeline through the first air outlet channel, the compressed air entering the cavity can be filled into the standard pipeline through the second air outlet channel, after the tested pipeline and the standard pipeline are filled with air (generally, the tested pipeline and the standard pipeline can be filled with air in an extended time mode), the driving end of the first cylinder drives the first piston to move downwards to enable the sealing gasket to block one end of the first air outlet channel and one end of the second air outlet channel, at this moment, the air inlet channel, one end of the first air outlet channel and one end of the second air outlet channel are not communicated with each other, then, the air pressure difference detection sensor starts to detect the air pressure difference between the first air outlet channel and the second air outlet channel, if the air pressure difference between the first air outlet channel and the second air outlet channel is smaller than a preset value, the situation that the detected pipeline has no leakage (the situation that the standard pipeline has no leakage) is indicated, and if the air pressure difference between the first air outlet channel and the second air outlet channel is larger than the preset value, the situation that the detected pipeline has leakage (the situation that the standard pipeline has no leakage) is indicated, so that the detected pipeline is unqualified, and the unqualified pipeline can be placed in an unqualified area in the subsequent working process of the pipeline air tightness detection equipment; after the detection is completed, the second cylinder can drive the second piston to move upwards, when the second piston moves upwards, the first sealing ring can remove the blockage of the third vent hole, at the moment, the compressed air filled in the detected pipeline can be discharged through the first air outlet channel, the third vent hole, the second valve seat, the exhaust joint and the air blowing pipe in sequence, and therefore the compressed air blown out through the air blowing pipe can blow off metal scraps in the pipeline end chamfering mechanism, namely the compressed air is recycled, and the purpose of saving energy is achieved.

The pipeline air tightness detection device of the utility model, wherein, each pipeline end sealing unit comprises a sliding seat and a third cylinder, the sliding seat is connected on the frame through a sliding rail component in a sliding way, the third cylinder is fixed on the frame, the sliding seat is fixed with the piston rod of the third cylinder, each pipeline end sealing unit also comprises an outer wrapping type pipeline end sealing joint or an inner expanding type pipeline end sealing joint which is fixed on the inner end surface of the sliding seat, the third cylinder is used for driving the sliding seat to move along the axial direction of the pipeline to be detected so as to enable the outer wrapping type pipeline end sealing joint or the inner expanding type pipeline end sealing joint to be close to or far away from the pipeline to be detected, when the outer wrapping type pipeline end sealing joint or the inner expanding type pipeline end sealing joint is close to the pipeline to be detected, the outer wrapping type pipeline end sealing joint or the inner expanding type pipeline end sealing joint is used for being in sealing connection with the end of the pipeline to be measured; one of the outer-wrapping type pipeline end sealing joint or the inner-expanding type pipeline end sealing joint in each pair of pipeline end sealing connecting devices is used for plugging one end of the tested pipeline, and the other outer-wrapping type pipeline end sealing joint or the inner-expanding type pipeline end sealing joint in each pair of pipeline end sealing connecting devices is connected with a first air outlet channel in the corresponding differential pressure detection combined type isolating valve; after adopting this kind of structure, after the piston rod of third cylinder extends, the third cylinder can drive the sliding seat and slide so that install the sealed joint of outer envelope formula pipeline end or the sealed joint of interior expanding pipeline end on the sliding seat and be connected with the tip sealing of pipeline under test, after the piston rod shrink of third cylinder, the third cylinder can drive the sliding seat and slide so that install the sealed joint of outer envelope formula pipeline end or the sealed joint of interior expanding pipeline end on the sliding seat and break away from the pipeline under test.

The utility model discloses a pipeline air tightness detection device, wherein, the outer wrapping type pipeline end part sealing joint comprises a first connecting seat, a first connecting joint, a third piston and a sealing ring group; a sliding cavity is arranged in one end of the first connecting seat, a third piston is slidably arranged in the sliding cavity, a third sealing structure is arranged between the third piston and the sliding cavity, a protruding part with the outer diameter smaller than that of the third piston is integrally formed at one end of the third piston, a concave cavity for the protruding part to insert and slide is arranged in the other end of the first connecting seat, a fourth sealing structure is arranged between the protruding part and the concave cavity, one end of the first connecting head is inserted into the sliding cavity, an annular convex edge is arranged on the outer wall of the other end of the first connecting head and fixed with the end part of one end of the first connecting seat, a first annular step is arranged on the inner wall of one end of the first connecting head, a sealing ring group is embedded in the first annular step and abuts against the first annular step, and the other end of the third piston is inserted into the first annular step and is used for extruding the sealing ring group when the third piston moves towards one side of the first connecting head, the first connector is provided with a jack for inserting one end of a pipeline to be detected, the other end of the third piston is provided with a slot for inserting one end of the pipeline to be detected when the third piston moves towards one side of the first connector, the other end of the first connector is provided with an inflation hole, the bulge is internally provided with an air guide channel which penetrates through the bulge and the third piston and is used for communicating the inflation hole with the jack, an annular first sealing cavity is formed between the third sealing structure and the fourth sealing structure, the first connector is internally provided with a first air inlet hole, one end of the first air inlet hole is communicated with the first sealing cavity, the other end of the first air inlet hole forms a first air inlet, when compressed air enters the first air inlet hole, the third piston is used for moving towards one side of the first connector and pressing the sealing ring group to enable the sealing ring group to deform and then to be tightly expanded with the inner wall of the first connector and the outer wall of the pipeline to be detected, the air inlet pressure of the first air inlet is greater than the air inlet pressure of the air filling hole, the air filling hole in one outer-wrapping type pipeline end sealing joint in each pair of pipeline end sealing connecting devices is plugged through a plug, and the air filling hole in the other outer-wrapping type pipeline end sealing joint in each pair of pipeline end sealing connecting devices is connected with a first air outlet channel in the corresponding differential pressure detection combined type isolating valve; this outer cladding formula pipeline end sealing joint is when carrying out sealing connection with the tip of being surveyed the pipeline, the tip of being surveyed the pipeline can insert first connector and sealing washer group, and under the effect of third piston, the third piston can push away the sealing washer group so that the sealing washer group produces the inner wall of deformation back with first connector and the outer wall of being surveyed the pipeline is bloated tightly, so, compare with the sealing mode that the tradition adopted tip to lean on, have with the end sealing of being surveyed the pipeline effectual and the high advantage of reliability, can effectively avoid appearing the condition of revealing between the tip of first connector and being surveyed the pipeline promptly, thereby can improve the precision and the reliability of the gas tightness detection to being surveyed the pipeline.

The pipeline air tightness detection device of the utility model is characterized in that the end face of the other end of the third piston is provided with an annular convex rib which is used for abutting against the sealing ring group and extruding the sealing ring group; after the annular convex rib is arranged at the other end of the third piston, when the third piston moves towards one side of the sealing ring group, the annular convex rib can extrude the sealing ring group, so that the sealing ring group can be better deformed, and the sealing ring group can be better expanded with the inner wall of the first connector and the outer wall of the pipeline to be measured; a support ring which is made of metal materials and used for allowing one end of a measured pipeline to penetrate is embedded between the inner bottom of the first annular step and the sealing ring group, one side of the support ring abuts against the inner bottom of the first annular step, the other side of the support ring abuts against the sealing ring group, and the support ring is used for supporting the sealing ring group; through the arrangement of the support ring, when the third piston moves towards one side of the sealing ring group and extrudes the sealing ring group, the sealing ring group can be better deformed, and thus, the sealing ring group can be better expanded with the inner wall of the first connector and the outer wall of the pipeline to be measured; the sealing ring group comprises a plurality of coaxially arranged second sealing rings, the plurality of second sealing rings are embedded in the first annular step, and every two adjacent second sealing rings are abutted against each other; after the sealing ring group is adopted, when the third piston moves towards one side of the sealing ring group and extrudes the sealing ring group, the sealing ring group can be well expanded with the inner wall of the first connector and the outer wall of the pipeline to be detected, and the sealing effect between the first connector and the pipeline to be detected can be improved; the third sealing structure comprises a third sealing ring, a second annular caulking groove is formed in the outer wall of the third piston, the third sealing ring is embedded in the second annular caulking groove, and the third sealing ring, the second annular caulking groove and the inner wall of the sliding cavity are tightly attached and sealed; by adopting the third sealing structure, reliable sealing can be realized between the third piston and the first connecting seat; a fifth air vent is arranged on the side wall of the first connecting seat and is used for being communicated with a sliding cavity between the third sealing ring and the first connecting head; through the arrangement of the fifth vent hole, when the third piston moves towards one side of the sealing ring group and extrudes the sealing ring group, air in the sliding cavity between the third sealing ring and the first connecting head can be discharged through the fifth vent hole, and similarly, when the third piston moves towards one side far away from the sealing ring group, air in the external environment can enter the sliding cavity between the third sealing ring and the first connecting head through the fifth vent hole, so that the balance of air pressure in the sliding cavity between the third sealing ring and the first connecting head can be ensured, and the third piston can move in the sliding cavity more smoothly; the fourth sealing structure comprises a fourth sealing ring and a fifth sealing ring, a third annular caulking groove and a fourth annular caulking groove are formed in the outer wall of the protruding portion and distributed along the axial direction of the protruding portion, the fourth sealing ring and the fifth sealing ring are respectively embedded in the third annular caulking groove and the fourth annular caulking groove, the fourth sealing ring, the third annular caulking groove and the inner wall of the cavity are tightly attached and sealed, and the fifth sealing ring, the fourth annular caulking groove and the inner wall of the cavity are tightly attached and sealed; by adopting the fourth sealing structure, reliable sealing can be realized between the convex part and the concave cavity; a second annular groove is formed in the outer wall of the protruding portion located between the third annular caulking groove and the fourth annular caulking groove, and a sixth vent hole is formed in the side wall of the first connecting seat and is used for being communicated with the second annular groove; through the arrangement of the sixth vent hole, when the third piston slides in the sliding cavity, air in the second annular groove can be discharged out of the first connecting seat through the sixth vent hole, or air in the external environment can enter the second annular groove through the sixth vent hole, so that the balance of air pressure between the fourth sealing ring and the fifth sealing ring can be ensured, and the third piston can move in the sliding cavity more smoothly; the annular convex edge is provided with a plurality of arc-shaped holes which are uniformly distributed in the circumferential direction, the end part of one end of the first connecting seat is provided with threaded holes which are in one-to-one correspondence with the arc-shaped holes, one end of each arc-shaped hole is provided with a small-hole diameter part, the other end of each arc-shaped hole is provided with a large-hole diameter part, the first connecting head is fixed with the first connecting seat through bolts which are arranged in the small-hole diameter parts in a penetrating mode and in threaded connection with the threaded holes, the inner diameter of each small-hole diameter part is larger than the outer diameter of the screw part of each bolt and smaller than the outer diameter of the head of each bolt, and the inner diameter of each large-hole diameter part is larger than the outer diameter of the head of each bolt; by adopting the structure, after each bolt is unscrewed, each large diameter part can be aligned with the bolt at the corresponding position by rotating the first connecting head, and because the inner diameter of each large diameter part is larger than the outer diameter of the head part of the bolt, the first connecting head can be detached from the first connecting seat by pulling the first connecting head, so that the replacement of the sealing ring group can be conveniently realized; after the sealing ring group is replaced, one end of the first connecting head can be inserted into the sliding cavity again, the head of each bolt penetrates through the large-hole part on the corresponding position, then the first connecting head is rotated to enable each small-hole part to be aligned with the bolt on the corresponding position, and finally each bolt is screwed down to enable the first connecting head and the first connecting seat to be fixed again; the inner wall of one end of the jack, which is far away from the first annular step, is provided with an annular conical surface, and the annular conical surface is used for being matched with the end part of the measured pipeline to guide so that the end part of the measured pipeline can be inserted into the jack and penetrates through the jack; after the annular conical surface is arranged on the inner wall of one end, far away from the first annular step, of the insertion hole, when the end part of the measured pipeline is to be inserted into the insertion hole, the end part of the measured pipeline can be guided in a matched mode with the annular conical surface so that the end part of the measured pipeline can be inserted into the insertion hole and penetrates through the insertion hole.

When the end part sealing joint of the outer wrapping type pipeline is used, firstly, the end part of a tested pipeline is inserted into the first connecting joint and the sealing ring group, then, compressed air is input into the first air inlet hole through the compressed air supply pipe, when compressed air enters the first air inlet hole, the compressed air can enter the first sealing cavity, at the moment, the third piston can move towards one side of the sealing ring group and extrude the sealing ring group to enable the sealing ring group to be tightly expanded with the inner wall of the first connecting joint and the outer wall of the tested pipeline after being deformed, and at the moment, the first connecting joint can be in sealing connection with the end part of the tested pipeline; when the compressed air supply pipe that is connected with first air inlet stops to supply compressed air to first air inlet in, and first air inlet when disappointing through the snuffle valve, under the effect of the resilience force of sealing washer group, the third piston can slide towards the one side of keeping away from sealing washer group and reset, so, sealing washer group can relieve the inner wall with first connector and the outer wall of being surveyed the pipeline is bloated tight, can relieve sealedly between first connector and the being surveyed pipeline, make at last the tip of being surveyed the pipeline deviate from sealing washer group and first connector can.

The utility model discloses a pipeline airtightness detection device, wherein, the inner expansion type pipeline end sealing joint comprises a second connecting seat, a second connecting head, a sliding sleeve and a third sealing ring; a seventh vent hole is formed in the second connecting seat, an eighth vent hole is coaxially formed in the second connecting seat, one end of the second connecting seat is inserted into the second connecting seat and fixed with the second connecting seat, a fifth sealing structure is arranged between one end of the second connecting seat and the second connecting seat, the other end of the second connecting seat is used for being inserted into one end of a pipeline to be tested, one end of the seventh vent hole is communicated with one end of the eighth vent hole, and an inflation port is formed at the other end of the seventh vent hole; a second annular step is arranged on the outer wall of the other end of the second connector, and a third sealing ring is sleeved outside the other end of the second connector and abuts against the second annular step; one end of the sliding sleeve is slidably sleeved outside the second connector and a sixth sealing structure is arranged between the sliding sleeve and the second connector, and the other end of the sliding sleeve is slidably sleeved outside the second connecting seat and a seventh sealing structure is arranged between the sliding sleeve and the second connecting seat; a second sealing cavity in an annular shape is defined by the fifth sealing structure, the sixth sealing structure and the seventh sealing structure, a second air inlet is formed in the second connecting seat, one end of the second air inlet is communicated with the second sealing cavity, and a second air inlet is formed at the other end of the second air inlet; the air inlet pressure of the second air inlet is greater than the air inlet pressure of the inflation inlet, the inflation inlet in one of the internal expansion type pipeline end sealing joints in each pair of pipeline end sealing connecting devices is plugged through a plug, and the inflation inlet in the other internal expansion type pipeline end sealing joint in each pair of pipeline end sealing connecting devices is connected with the first air outlet channel in the corresponding differential pressure detection combined type isolating valve; after adopting this kind of interior expanding pipeline end sealing joint, when interior expanding pipeline end sealing joint carries out sealing connection with the tip of being surveyed the pipeline, the other end of second connector can insert in the tip of being surveyed the pipeline, and under the effect of sliding sleeve, the sliding sleeve can push away the third sealing washer so that the outer wall that produces deformation back and second connector and the inner wall of being surveyed the pipeline expand tightly, so, compare with the sealing method that the tradition adopted tip to lean on, have with the end seal of being surveyed the pipeline effectual and the high advantage of reliability, can effectively avoid appearing revealing the condition between the tip of second connector and being surveyed the pipeline promptly, thereby can improve the precision and the reliability of the gas tightness detection to being surveyed the pipeline.

The utility model discloses a pipeline airtightness detection device, wherein, one end of the second connector is coaxially provided with a screwed joint with the outer diameter smaller than that of the second connector, the inner wall of the second connecting seat is provided with internal threads, and the screwed joint is connected with the internal threads in a threaded manner; by adopting the structure, one end of the second connector can be reliably and fixedly connected with the first connecting seat; a countersunk head part in a regular hexagon shape is arranged on the inner wall of the other end of the second connector; after the inner wall of the other end of the second connector is provided with the regular hexagonal countersunk head part, when one end of the second connector is in threaded connection with the second connecting seat, the external hexagonal wrench can be inserted into the countersunk head part and the second connector is screwed by the external hexagonal wrench, so that one end of the second connector can be conveniently in threaded connection with the second connecting seat; an annular chamfer surface which is used for being matched and guided with the inner wall of the measured pipeline so as to facilitate the other end of the second connector to be inserted into the measured pipeline is arranged on the outer wall of the other end of the second connector; after the annular chamfer surface is arranged on the outer wall of the other end of the second connector, the annular chamfer surface can be matched with the inner wall of the pipeline to be detected to guide in the process that the other end of the second connector is inserted into the pipeline to be detected so as to facilitate the insertion of the other end of the second connector into the pipeline to be detected; the fifth sealing structure comprises a sixth sealing ring, a fifth annular caulking groove is formed in the outer wall of one end of the second connector, the sixth sealing ring is embedded in the fifth annular caulking groove, and the sixth sealing ring, the fifth annular caulking groove and the second connecting seat are tightly sealed; by adopting the fifth sealing structure, reliable sealing can be realized between one end of the second connector and the second connecting seat; the sixth sealing structure comprises a seventh sealing ring, a sixth annular caulking groove is formed in the inner wall of one end of the sliding sleeve, the seventh sealing ring is embedded in the sixth annular caulking groove, and the seventh sealing ring, the sixth annular caulking groove and the outer wall of the second connector are tightly attached and sealed; by adopting the sixth sealing structure, reliable sealing can be realized between one end of the sliding sleeve and the outer wall of the second connector; the seventh sealing structure comprises an eighth sealing ring, a seventh annular caulking groove is formed in the outer wall of the second connecting seat, the eighth sealing ring is embedded in the seventh annular caulking groove, and the eighth sealing ring, the seventh annular caulking groove and the inner wall of the other end of the sliding sleeve are tightly attached and sealed; by adopting the seventh sealing structure, reliable sealing can be realized between the other end of the sliding sleeve and the second connecting seat; a pushing sleeve made of a metal material is slidably sleeved outside a second connector positioned between the third sealing ring and the sliding sleeve, one end of the pushing sleeve is used for abutting against the third sealing ring, and the other end of the pushing sleeve is used for abutting against one end of the sliding sleeve; after the pushing sleeve made of a metal material is sleeved outside the second connector between the third sealing ring and the sliding sleeve, when the sliding sleeve moves towards one side of the third sealing ring, the sliding sleeve can push the pushing sleeve, and the pushing sleeve can reliably push the third sealing ring.

When the internal expansion type pipeline end part sealing joint is used, firstly, the other end of the second connector and a third sealing ring positioned at the other end of the second connector are inserted into the end part of a pipeline to be measured, then, a compressed air supply pipe inputs compressed air into a second air inlet hole, when the compressed air enters the second air inlet hole, the compressed air can enter a second sealing cavity, at the moment, one end of the sliding sleeve can move towards one side of the third sealing ring and extrude the third sealing ring to enable the third sealing ring to be tightly expanded with the outer wall of the second connector and the inner wall of the pipeline to be measured after being deformed, and at the moment, the second connector and the end part of the pipeline to be measured can be in sealing connection; when the compressed air supply pipe that is connected with the second air inlet stops to supply compressed air to in the second air inlet, and the second air inlet when disappointing through the snuffle valve, under the effect of the resilience force of third sealing washer, push away cover and sliding sleeve and can slide towards the one side of keeping away from the third sealing washer and reset, so, the third sealing washer can relieve with the outer wall of second connector and the bloated tightness of the inner wall of pipeline under test, can relieve sealedly between second connector and the pipeline under test promptly, make the other end of second connector and the third sealing washer that is located second connector other end department deviate from the tip of pipeline under test at last.

The utility model has the advantages that through the arrangement of a plurality of differential pressure detection combined type isolating valves, each differential pressure detection combined type isolating valve can simultaneously control the inflation and the stop of the inflation of a detected pipeline and a standard pipeline, thereby having the advantage of simple control and simplifying the structure of pipeline air tightness detection equipment; furthermore, the utility model discloses can carry out automated inspection to the gas tightness of being surveyed the pipeline, have degree of automation height and detect convenient advantage to being surveyed the pipeline gas tightness.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

fig. 1 is a schematic perspective view of the present invention;

FIG. 2 is an enlarged view of the structure at A in FIG. 1;

FIG. 3 is a schematic diagram of a first perspective view of a differential pressure sensing block valve;

FIG. 4 is a schematic diagram of a second perspective view of a differential pressure sensing block valve;

FIG. 5 is a schematic front view of a pressure differential sensing block valve;

FIG. 6 is a first schematic cross-sectional side view of a differential pressure sensing block valve;

FIG. 7 is a second schematic perspective cross-sectional view of a differential pressure sensing block valve;

FIG. 8 is a cross-sectional structural schematic view of a differential pressure sensing block valve;

FIG. 9 is an enlarged view of the structure at B in FIG. 8;

FIG. 10 is an enlarged view of the structure at C in FIG. 8;

FIG. 11 is a partially exploded perspective view of a pressure differential sensing block valve;

FIG. 12 is a first perspective view of the overwrap pipe end seal;

FIG. 13 is a second perspective view of the overwrap pipe end seal;

FIG. 14 is a cross-sectional structural schematic view of an overwrap pipe end seal joint;

FIG. 15 is an enlarged view of D of FIG. 14;

FIG. 16 is a first perspective view of an end seal joint of an internally expanding conduit;

FIG. 17 is a second perspective view of the sealing joint at the end of the internally expanding conduit;

fig. 18 is a cross-sectional view of an end seal joint of an internal expansion type pipe.

Detailed Description

In the following description, numerous implementation details are set forth in order to provide a more thorough understanding of the present invention. It should be understood, however, that these implementation details should not be used to limit the invention. That is, in some embodiments of the invention, details of these implementations are not necessary. In addition, some conventional structures and components are shown in simplified schematic form in the drawings.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for description purposes, not specifically referring to the order or sequence, and are not intended to limit the present invention, but only to distinguish the components or operations described in the same technical terms, and are not to be construed as indicating or implying any relative importance or implicit indication of the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

As shown in fig. 1-18, the pipeline air-tightness detecting device of the present invention comprises a frame 1, a plurality of pressure difference detecting combined type block valves 2 and a plurality of pressure difference detecting sensors, wherein the pressure difference detecting combined type block valves 2 and the pressure difference detecting sensors are respectively in one-to-one correspondence with each detected pipeline 3, and a standard pipeline 4 in one-to-one correspondence with each detected pipeline 3 is fixed on the frame 1; a plurality of pairs of pipeline end part sealing connection devices are installed on the rack 1, two pipeline end part sealing units in each pair of pipeline end part sealing connection devices are respectively installed on the rack 1 at the positions of two end parts of the corresponding detected pipeline 3, each pipeline end part sealing unit is used for being in sealing connection with one end of the corresponding detected pipeline 3, one pipeline end part sealing unit in each pair of pipeline end part sealing connection devices is used for plugging one end of the detected pipeline 3, the other pipeline end part sealing unit in each pair of pipeline end part sealing connection devices is connected with a first air outlet channel in the corresponding pressure difference detection combined type isolating valve 2, one end of each standard pipeline 4 is plugged, the other end of each standard pipeline 4 is connected with a second air outlet channel in the corresponding pressure difference detection combined type isolating valve 2, and the other end of each standard pipeline can be communicated with a second air outlet channel in the corresponding pressure difference detection combined type isolating valve through a pipeline The two air inlet ends of each air pressure difference detection sensor are respectively connected with a first air outlet channel and a second air outlet channel in the corresponding pressure difference detection combined type block valve 2; in the structure, the independent electromagnets can be adopted to adsorb each measured pipeline in a pick-and-place mode, for example, a support frame is arranged on a manipulator, the electromagnets which correspond to each measured pipeline in a one-to-one mode are arranged at the bottom of the support frame, when the electromagnets are electrified, the electromagnets can adsorb the measured pipelines in a magnetic mode, and when the electromagnets are powered off, the electromagnets can release the measured pipelines, so that the measured pipelines can be conveniently moved.

Each differential pressure detection combined type block valve 2 comprises a base 21, a first valve seat 22, a first air cylinder 23 and a first piston 24; the lower end of the first valve seat 22 is fixed on the base 21, a first sealing structure is arranged between the lower end of the first valve seat 22 and the base 21, a cavity 25 is formed between the first valve seat 22 and the base 21, the first cylinder 23 is fixed at the upper end of the first valve seat 22, the first piston 24 is vertically slidably arranged in the first valve seat 22 in a penetrating manner, the lower end of the first piston 24 extends into the cavity 25, a second sealing structure is arranged between the first piston 24 and the first valve seat 22, the upper end of the first piston 24 is connected with the driving end of the first cylinder 23, the base 21 is provided with an air inlet channel 211, a first air outlet channel 212 and a second air outlet channel 213, one end of the air inlet channel 211, one end of the first air outlet channel 212 and one end of the second air outlet channel 213 are all communicated with the cavity 25, the other end of the air inlet channel 211 is used for being connected with an air inlet pipe, the other end of the first air outlet channel 212 is used for being connected with another pipe end sealing unit in the corresponding pipe end sealing connection device, the other end of the second air outlet channel 213 is used for being connected with the other end of the corresponding standard pipeline 4, a sealing gasket 241 is embedded at the lower end of the first piston 24, after the first piston 24 is driven by the first air cylinder 23 to move downwards, the sealing gasket 241 is used for abutting against the upper end surface of the base 21 and used for sealing one end of the first air outlet channel 212 and one end of the second air outlet channel 213, the base 21 is further provided with a first air vent 214 and a second air vent 215, one end of the first air vent 214 and one end of the second air vent 215 are respectively communicated with the first air outlet channel 212 and the second air outlet channel 213, the other end of the first air vent 214 is used for being connected with one air inlet end of the corresponding air pressure difference detection sensor, and the other end of the second air vent 215 is used for being connected with the other air inlet end of the corresponding air pressure difference detection sensor; after the differential pressure detection combined type block valve is adopted, the inflation of the detected pipeline and the standard pipeline can be controlled and stopped at the same time.

The outer edge of one end of the first air outlet channel 212 and the outer edge of one end of the second air outlet channel 213 both protrude from the upper end surface of the base 21; after the outer edge of one end of the first air outlet channel and the outer edge of one end of the second air outlet channel are both arranged to be protruded out of the upper end face of the base, the outer edge of one end of the first air outlet channel and the outer edge of one end of the second air outlet channel can better extrude the sealing gasket after the first piston is driven by the first cylinder to move downwards, and therefore the sealing gasket can more reliably seal one end of the first air outlet channel and one end of the second air outlet channel; the first sealing structure comprises a first sealing ring 221, an annular boss 222 is arranged on the lower end face of the first valve seat 22, a first annular groove 216 is arranged on the upper end face of the base 21, the first sealing ring 221 is embedded in the first annular groove 216, the annular boss 222 is inserted into the first annular groove 216 and used for pressing the first sealing ring 221, and the first sealing ring 221, the first annular groove 216 and the annular boss 222 are tightly sealed; by adopting the first sealing structure, after the first valve seat is assembled on the base, the lower end of the first valve seat and the base can be reliably sealed; the second sealing structure comprises a plurality of second sealing rings 242 distributed along the axial direction of the first piston 24, first annular embedding grooves 243 corresponding to the second sealing rings 242 one by one are arranged on the outer wall of the first piston 24, each second sealing ring 242 is embedded in the first annular embedding groove 243 at the corresponding position, and each second sealing ring 242 is tightly attached and sealed with the inner wall of the first valve seat 22 and the first annular embedding groove 243 at the corresponding position; by adopting the second sealing structure, the first piston and the first valve seat can be reliably sealed; a T-shaped clamping groove 244 is formed in the upper end of the first piston 24, a T-shaped clamping block 231 is arranged at the driving end of the first air cylinder 23, and the clamping block 231 is matched and clamped with the clamping groove 244; after adopting this kind of structure, the upper end of first piston can link together with the drive end of first cylinder reliably, and when the drive end of first cylinder contracts, first cylinder can drive first piston and shift up, and when the drive end of first cylinder extended, first cylinder can drive first piston and move down.

The pressure difference detection combined type block valve 2 further comprises a second valve seat 26, a second cylinder 27 and a second piston 28, the lower end of the second valve seat 26 is fixed on the base 21, the second cylinder 27 is fixed with the upper end of the second valve seat 26, the second piston 28 is vertically slidably mounted in the second valve seat 26, the upper end of the second piston 28 is fixed with the driving end of the second cylinder 27, the lower end of the second piston 28 is provided with an insertion rod 281 with an outer diameter smaller than that of the second piston 28, the outside of the insertion rod 281 is sleeved with a first sealing ring 282, the base 21 is internally provided with a third vent hole 217, one end of the third vent hole 217 is communicated with the first vent channel 212, after the second cylinder 27 drives the second piston 28 to move downwards, the lower end of the insertion rod 281 is used for being inserted into the other end of the third vent hole 217, the first sealing ring 282 is used for abutting against the upper end face of the base 21 and sealing off the third vent hole 217, the side wall of the second valve seat 26 is connected with an exhaust joint 261, after the second cylinder 27 drives the second piston 28 to move up, the exhaust joint 261 is used for communicating with the third vent hole 217 through the second valve seat 26; by adopting the structure, after the detected pipeline is detected, when the second cylinder drives the second piston to move upwards, the sealing ring can remove the blockage of the third vent hole, and at the moment, the compressed air filled in the detected pipeline can be discharged through the first air outlet channel, the third vent hole, the second valve seat and the exhaust joint in sequence, so that when the exhaust joint is connected with one end of the air blow pipe and one end of the air blow pipe is arranged in the pipeline end chamfering mechanism, the compressed air blown out by the air blow pipe can blow off metal debris in the pipeline end chamfering mechanism, namely the compressed air is reused, and the purpose of saving energy is achieved; the outer edge of the other end of the third vent hole 217 protrudes out of the upper end face of the base 21; after adopting this kind of structure, after second cylinder drive second piston moves down, the outward flange of third ventilation hole other end can realize the extrusion to first sealing washer better, so, first sealing washer can realize the shutoff to third ventilation hole better.

A fourth air vent 218 is further arranged on the base 21, one end of the fourth air vent 218 is communicated with the first air outlet channel 212, and the other end of the fourth air vent 218 is used for being connected with a barometer; by adopting the structure, the staff can clearly know the real-time air pressure in the first air outlet channel through the air pressure meter.

When the pressure difference detection combined type block valve works, the driving end of the first cylinder drives the first piston to move downwards to enable the first sealing ring to block the third vent hole, then the driving end of the first cylinder drives the first piston to move upwards to enable the sealing gasket to unblock one end of the first air outlet channel and one end of the second air outlet channel, at the moment, compressed air from the air inlet pipe can enter the cavity through the air inlet channel, the compressed air entering the cavity can be filled into the tested pipeline through the first air outlet channel, the compressed air entering the cavity can be filled into the standard pipeline through the second air outlet channel, after the tested pipeline and the standard pipeline are filled with air (generally, the tested pipeline and the standard pipeline can be filled with air in an extended time mode), the driving end of the first cylinder drives the first piston to move downwards to enable the sealing gasket to block one end of the first air outlet channel and one end of the second air outlet channel, at this moment, the air inlet channel, one end of the first air outlet channel and one end of the second air outlet channel are not communicated with each other, then, the air pressure difference detection sensor starts to detect the air pressure difference between the first air outlet channel and the second air outlet channel, if the air pressure difference between the first air outlet channel and the second air outlet channel is smaller than a preset value, the situation that the detected pipeline has no leakage (the situation that the standard pipeline has no leakage) is indicated, and if the air pressure difference between the first air outlet channel and the second air outlet channel is larger than the preset value, the situation that the detected pipeline has leakage (the situation that the standard pipeline has no leakage) is indicated, so that the detected pipeline is unqualified, and the unqualified pipeline can be placed in an unqualified area in the subsequent working process of the pipeline air tightness detection equipment; after the detection is finished, the second cylinder can drive the second piston to move upwards, when the second piston moves upwards, the first sealing ring can remove the blockage of the third vent hole, at the moment, the compressed air filled in the detected pipeline can be discharged through the first air outlet channel, the third vent hole, the second valve seat, the exhaust joint and the air blowing pipe in sequence, and therefore the compressed air blown out through the air blowing pipe can blow off metal fragments in the chamfering mechanism at the end part of the pipeline, namely, the compressed air is recycled, and the purpose of saving energy is achieved.

Each pipeline end sealing unit comprises a sliding seat 51 and a third air cylinder 52, the sliding seat 51 is connected to the rack 1 in a sliding mode through a sliding rail assembly 53, the third air cylinder 52 is fixed to the rack 1, the sliding seat 51 is fixed to a piston rod of the third air cylinder 52, each pipeline end sealing unit further comprises an outer wrapping type pipeline end sealing joint 6 or an inner expanding type pipeline end sealing joint 7 fixed to the inner end face of the sliding seat 51, the third air cylinder 52 is used for driving the sliding seat 51 to move along the axial direction of the pipeline 3 to be tested so that the outer wrapping type pipeline end sealing joint 6 or the inner expanding type pipeline end sealing joint 7 can be close to or far away from the pipeline 3 to be tested, when the outer wrapping type pipeline end sealing joint 6 or the inner expanding type pipeline end sealing joint 7 is close to the pipeline 3 to be tested, the outer wrapping type pipeline end sealing joint 6 or the inner expanding type pipeline end sealing joint 7 is used for being connected with the end of the tested pipeline 3 in a sealing mode; one of the outer-wrapping type pipeline end sealing joint 6 or the inner-expanding type pipeline end sealing joint 7 in each pair of pipeline end sealing connecting devices is used for plugging one end of the tested pipeline 3, and the other outer-wrapping type pipeline end sealing joint 6 or the inner-expanding type pipeline end sealing joint 7 in each pair of pipeline end sealing connecting devices is connected with the corresponding first air outlet channel 212 in the differential pressure detection combined type isolating valve 2; after adopting this kind of structure, after the piston rod of third cylinder extends, the third cylinder can drive the sliding seat and slide so that install the sealed joint of outer envelope formula pipeline end or the sealed joint of interior expanding pipeline end on the sliding seat and be connected with the tip sealing of pipeline under test, after the piston rod shrink of third cylinder, the third cylinder can drive the sliding seat and slide so that install the sealed joint of outer envelope formula pipeline end or the sealed joint of interior expanding pipeline end on the sliding seat and break away from the pipeline under test.

The overclad tube end seal joint 6 comprises a first connection seat 61, a first connection head 62, a third piston 63 and a seal ring set 64; a sliding cavity 611 is formed in one end of the first connecting seat 61, the third piston 63 is slidably installed in the sliding cavity 611, a third sealing structure is arranged between the third piston 63 and the sliding cavity 611, a protruding portion 631 having an outer diameter smaller than that of the third piston 63 is integrally formed at one end of the third piston 63, a concave cavity 612 into which the protruding portion 631 is inserted and slides is formed in the other end of the first connecting seat 61, a fourth sealing structure is formed between the protruding portion 631 and the concave cavity 612, one end of the first connecting head 62 is inserted into the sliding cavity 611, an annular convex edge 621 is formed on an outer wall of the other end of the first connecting head 62, the annular convex edge 621 is fixed to an end of one end of the first connecting seat 61, a first annular step 622 is formed on an inner wall of one end of the first connecting head 62, a sealing ring group 64 is embedded in the first annular step 622 and abuts against the first annular step 622, and the other end of the third piston 63 is inserted into the first annular step 622 and used when the third piston 63 moves toward one side of the first connecting head 62 In the packing group 64, the first connector 62 is provided with an insertion hole 623 for inserting one end of the pipe 3 to be tested, the other end of the third piston 63 is provided with an insertion groove 632 for inserting one end of the pipe to be tested when the third piston 63 moves towards one side of the first connector 62, the other end of the first connector 61 is provided with an inflation hole 613, the protrusion 631 is provided with an air guide channel 633 penetrating the protrusion 631 and the third piston 63 and communicating the inflation hole 613 with the insertion hole 623, an annular first sealing cavity 65 is formed between the third sealing structure and the fourth sealing structure, the first connector 61 is provided with a first air inlet 614, one end of the first air inlet 614 is communicated with the first sealing cavity 65, the other end of the first air inlet 614 forms a first air inlet 615, when compressed air enters the first air inlet 615, the third piston 63 is used for moving towards one side of the first connector 62 and pressing the packing group 64 to deform the packing group 64 and then the first connector The inner wall of the joint 62 and the outer wall of the pipeline 3 to be detected are expanded tightly, the air inlet pressure of the first air inlet 615 is greater than the air inlet pressure of the air charging hole 613, the air charging hole 613 in one outer-wrapping type pipeline end sealing joint 6 in each pair of pipeline end sealing connecting devices is plugged by a plug, the air charging hole 613 in the other outer-wrapping type pipeline end sealing joint 6 in each pair of pipeline end sealing connecting devices is connected with the first air outlet channel 212 in the corresponding differential pressure detection combined type isolating valve 2, and the air charging hole can be connected with the first air outlet channel by adopting a pipeline; this outer packet of formula pipeline tip sealing joint is when carrying out sealing connection with the tip of being surveyed the pipeline, the tip of being surveyed the pipeline can insert first connector and sealing washer group, and under the effect of third piston, the third piston can push away the sealing washer group so that the sealing washer group produce after deformation expand tightly with the inner wall of first connector and the outer wall of being surveyed the pipeline, so, compare with the sealing method that the tradition adopted tip to counterbalance, have with the tip of being surveyed the pipeline sealed effectual and the high advantage of reliability, can effectively avoid appearing the condition of revealing between the tip of first connector and being surveyed the pipeline promptly, thereby can improve precision and the reliability of the gas tightness detection to being surveyed the pipeline.

An annular convex rib 634 is arranged on the end face of the other end of the third piston 63, and the annular convex rib 634 is used for abutting against the sealing ring group 64 and extruding the sealing ring group 64; after the annular convex rib is arranged at the other end of the third piston, when the third piston moves towards one side of the sealing ring group, the annular convex rib can extrude the sealing ring group, so that the sealing ring group can be better deformed, and the sealing ring group can be better expanded with the inner wall of the first connector and the outer wall of the pipeline to be measured; a support ring 66 which is made of metal materials and is used for allowing one end of a measured pipeline to pass through is embedded between the inner bottom of the first annular step 622 and the seal ring group 64, one side of the support ring 66 abuts against the inner bottom of the first annular step 622, the other side of the support ring 66 abuts against the seal ring group 64, and the support ring 66 is used for supporting the seal ring group 64; through the arrangement of the support ring, when the third piston moves towards one side of the sealing ring group and extrudes the sealing ring group, the sealing ring group can be better deformed, and thus, the sealing ring group can be better expanded with the inner wall of the first connector and the outer wall of the pipeline to be measured; the sealing ring group 64 includes a plurality of coaxially disposed second sealing rings 641, the plurality of second sealing rings 641 are embedded in the first annular step 622, and every two adjacent second sealing rings 641 are abutted against each other; after the sealing ring group is adopted, when the third piston moves towards one side of the sealing ring group and extrudes the sealing ring group, the sealing ring group can be well expanded with the inner wall of the first connector and the outer wall of the pipeline to be detected, and the sealing effect between the first connector and the pipeline to be detected can be improved; the third sealing structure comprises a third sealing ring 67, a second annular caulking groove 635 is formed in the outer wall of the third piston 63, the third sealing ring 67 is embedded in the second annular caulking groove 635, and the third sealing ring 67, the second annular caulking groove 635 and the inner wall of the sliding cavity 611 are tightly attached and sealed; by adopting the third sealing structure, reliable sealing can be realized between the third piston and the first connecting seat; a fifth vent hole 616 is formed in the side wall of the first connecting seat 61, and the fifth vent hole 616 is used for communicating with a sliding cavity 611 between the third sealing ring 67 and the first connecting head 62; through the arrangement of the fifth vent hole, when the third piston moves towards one side of the sealing ring group and extrudes the sealing ring group, air in the sliding cavity between the third sealing ring and the first connecting head can be discharged through the fifth vent hole, and similarly, when the third piston moves towards one side far away from the sealing ring group, air in the external environment can enter the sliding cavity between the third sealing ring and the first connecting head through the fifth vent hole, so that the balance of air pressure in the sliding cavity between the third sealing ring and the first connecting head can be ensured, and the third piston can move in the sliding cavity more smoothly; the fourth sealing structure comprises a fourth sealing ring 68 and a fifth sealing ring 69, a third annular caulking groove 636 and a fourth annular caulking groove 637 are arranged on the outer wall of the projecting part 631, the third annular caulking groove 636 and the fourth annular caulking groove 637 are distributed along the axial direction of the projecting part 631, the fourth sealing ring 68 and the fifth sealing ring 69 are respectively embedded in the third annular caulking groove 636 and the fourth annular caulking groove 637, the fourth sealing ring 68, the third annular caulking groove 636 and the inner wall of the cavity 612 are tightly sealed, and the fifth sealing ring 69, the fourth annular caulking groove 637 and the inner wall of the cavity 612 are tightly sealed; by adopting the fourth sealing structure, reliable sealing can be realized between the convex part and the concave cavity; a second annular groove 638 is formed in the outer wall of the projection 631 located between the third annular groove 636 and the fourth annular groove 637, a sixth vent hole 617 is formed in the side wall of the first connecting seat 61, and the sixth vent hole 617 is used for communicating with the second annular groove 638; through the arrangement of the sixth vent hole, when the third piston slides in the sliding cavity, air in the second annular groove can be discharged out of the first connecting seat through the sixth vent hole, or air in the external environment can enter the second annular groove through the sixth vent hole, so that the balance of air pressure between the fourth sealing ring and the fifth sealing ring can be ensured, and the third piston can move in the sliding cavity more smoothly; a plurality of arc-shaped holes 624 are uniformly distributed in the circumferential direction in the annular convex edge 621, a threaded hole 618 corresponding to each arc-shaped hole 624 one to one is arranged at the end part of one end of the first connecting seat 61, a small hole radial part 6241 is arranged at one end of each arc-shaped hole 624, a large hole radial part 6242 is arranged at the other end of each arc-shaped hole 624, the first connecting head 62 is fixed with the first connecting seat 61 through a bolt which is arranged in the small hole radial part 6241 in a penetrating manner and is in threaded connection with the threaded hole 618, the inner diameter of each small hole radial part 6241 is larger than the outer diameter of the screw part of the bolt and smaller than the outer diameter of the head of the bolt, and the inner diameter of each large hole radial part 6242 is larger than the outer diameter of the head of the bolt; by adopting the structure, after each bolt is unscrewed, each large diameter part can be aligned with the bolt at the corresponding position by rotating the first connecting head, and because the inner diameter of each large diameter part is larger than the outer diameter of the head part of the bolt, the first connecting head can be detached from the first connecting seat by pulling the first connecting head, so that the replacement of the sealing ring group can be conveniently realized; after the sealing ring group is replaced, one end of the first connecting head can be inserted into the sliding cavity again, the head of each bolt penetrates through the large-hole part on the corresponding position, then the first connecting head is rotated to enable each small-hole part to be aligned with the bolt on the corresponding position, and finally each bolt is screwed down to enable the first connecting head and the first connecting seat to be fixed again; the inner wall of the insertion hole 623 at one end far away from the first annular step 622 is provided with an annular conical surface 6231, and the annular conical surface 6231 is used for being matched and guided with the end part of the measured pipeline 3 so as to facilitate the end part of the measured pipeline 3 to be inserted into the insertion hole 623 and penetrate through the insertion hole 623; after the annular conical surface is arranged on the inner wall of one end, far away from the first annular step, of the insertion hole, when the end part of the measured pipeline is to be inserted into the insertion hole, the end part of the measured pipeline can be guided in a matched mode with the annular conical surface so that the end part of the measured pipeline can be inserted into the insertion hole and penetrates through the insertion hole.

When the end part sealing joint of the outer wrapping type pipeline is used, firstly, the end part of a tested pipeline is inserted into the first connecting joint and the sealing ring group, then, compressed air is input into the first air inlet hole through the compressed air supply pipe, when compressed air enters the first air inlet hole, the compressed air can enter the first sealing cavity, at the moment, the third piston can move towards one side of the sealing ring group and extrude the sealing ring group to enable the sealing ring group to be tightly expanded with the inner wall of the first connecting joint and the outer wall of the tested pipeline after being deformed, and at the moment, the first connecting joint can be in sealing connection with the end part of the tested pipeline; when the compressed air supply pipe connected with the first air inlet stops supplying compressed air into the first air inlet, and the first air inlet is deflated through the air escape valve, the third piston can slide towards one side far away from the sealing ring group to reset under the action of resilience force of the sealing ring group, so that the sealing ring group can release the expansion of the inner wall of the first connecting head and the outer wall of the pipeline to be detected, namely the sealing between the first connecting head and the pipeline to be detected can be released, and finally the end part of the pipeline to be detected can be separated from the sealing ring group and the first connecting head; in addition, the externally wrapped type pipeline end sealing joint can be suitable for a tested pipeline with a smaller outer diameter.

The inner expansion type pipeline end sealing joint 7 comprises a second connecting seat 71, a second connecting head 72, a sliding sleeve 73 and a third sealing ring 74; a seventh vent hole 711 is formed in the second connecting seat 71, an eighth vent hole 721 is coaxially formed in the second connecting head 72, one end of the second connecting head 72 is inserted into the second connecting seat 71 and fixed with the second connecting seat 71, a fifth sealing structure is arranged between one end of the second connecting head 72 and the second connecting seat 71, the other end of the second connecting head 72 is used for being inserted into one end of the measured pipeline 3, one end of the seventh vent hole 711 is communicated with one end of the eighth vent hole 721, and an inflation port 712 is formed at the other end of the seventh vent hole 711; a second annular step 722 is arranged on the outer wall of the other end of the second connector 72, and the third sealing ring 74 is sleeved outside the other end of the second connector 72 and abuts against the second annular step 722; one end of the sliding sleeve 73 is slidably sleeved outside the second connector 72 and a sixth sealing structure is arranged between the sliding sleeve 73 and the second connector 72, and the other end of the sliding sleeve 73 is slidably sleeved outside the second connecting seat 71 and a seventh sealing structure is arranged between the sliding sleeve 73 and the second connecting seat 71; the fifth sealing structure, the sixth sealing structure and the seventh sealing structure enclose an annular second sealing cavity 75, a second air inlet 713 is formed in the second connecting seat 71, one end of the second air inlet 713 is communicated with the second sealing cavity 75, the other end of the second air inlet 713 forms a second air inlet 714, when compressed air enters the second air inlet 714, one end of the sliding sleeve 73 is used for moving towards one side of the third sealing ring 74 and pressing the third sealing ring 74 so that the third sealing ring 74 deforms and then expands tightly with the outer wall of the second connecting head 72 and the inner wall of the measured pipeline 3; the air inlet pressure of the second air inlet 714 is greater than the air inlet pressure of the air charging port 712, the air charging port 712 in one inward-expanding type pipeline end sealing joint 7 in each pair of pipeline end sealing connecting devices is plugged by a plug, the air charging port 712 in the other inward-expanding type pipeline end sealing joint 7 in each pair of pipeline end sealing connecting devices is connected with the first air outlet channel 212 in the corresponding differential pressure detection combined type isolating valve 2, and the air charging port and the first air outlet channel can be connected by adopting a pipeline; after adopting this kind of interior expanding pipeline end sealing joint, when interior expanding pipeline end sealing joint carries out sealing connection with the tip of being surveyed the pipeline, the other end of second connector can insert in the tip of being surveyed the pipeline, and under the effect of sliding sleeve, the sliding sleeve can push away the third sealing washer so that the outer wall that produces deformation back and second connector and the inner wall of being surveyed the pipeline expand tightly, so, compare with the sealing method that the tradition adopted tip to lean on, have with the end seal of being surveyed the pipeline effectual and the high advantage of reliability, can effectively avoid appearing revealing the condition between the tip of second connector and being surveyed the pipeline promptly, thereby can improve the precision and the reliability of the gas tightness detection to being surveyed the pipeline.

One end of the second connector 72 is coaxially provided with a threaded connector 723 with the outer diameter smaller than that of the second connector 72, the inner wall of the second connecting seat 71 is provided with internal threads 715, and the threaded connector 723 is in threaded connection with the internal threads 715; by adopting the structure, one end of the second connector can be reliably and fixedly connected with the first connecting seat; a countersunk head 724 in a regular hexagon shape is arranged on the inner wall of the other end of the second connector 72; after the inner wall of the other end of the second connector is provided with the regular hexagonal countersunk head part, when one end of the second connector is in threaded connection with the second connecting seat, the external hexagonal wrench can be inserted into the countersunk head part and the second connector is screwed by the external hexagonal wrench, so that one end of the second connector can be conveniently in threaded connection with the second connecting seat; an annular chamfer surface 725 which is used for being matched and guided with the inner wall of the measured pipeline 3 so as to facilitate the other end of the second connector 72 to be inserted into the measured pipeline 3 is arranged on the outer wall of the other end of the second connector 72; after the annular chamfer surface is arranged on the outer wall of the other end of the second connector, the annular chamfer surface can be matched with the inner wall of the pipeline to be detected to guide in the process that the other end of the second connector is inserted into the pipeline to be detected so as to facilitate the insertion of the other end of the second connector into the pipeline to be detected; the fifth sealing structure comprises a sixth sealing ring 76, a fifth annular caulking groove 726 is arranged on the outer wall of one end of the second connector 72, the sixth sealing ring 76 is embedded in the fifth annular caulking groove 726, and the sixth sealing ring 76, the fifth annular caulking groove 726 and the second connecting seat 71 are tightly attached and sealed; by adopting the fifth sealing structure, reliable sealing can be realized between one end of the second connector and the second connecting seat; the sixth sealing structure comprises a seventh sealing ring 77, a sixth annular caulking groove 731 is arranged on the inner wall of one end of the sliding sleeve 73, the seventh sealing ring 77 is embedded in the sixth annular caulking groove 731, and the seventh sealing ring 77, the sixth annular caulking groove 731 and the outer wall of the second connector 72 are tightly attached and sealed; by adopting the sixth sealing structure, reliable sealing can be realized between one end of the sliding sleeve and the outer wall of the second connector; the seventh sealing structure comprises an eighth sealing ring 78, a seventh annular caulking groove 716 is formed in the outer wall of the second connecting seat 71, the eighth sealing ring 78 is embedded in the seventh annular caulking groove 716, and the eighth sealing ring 78, the seventh annular caulking groove 716 and the inner wall of the other end of the sliding sleeve 73 are tightly attached and sealed; by adopting the seventh sealing structure, reliable sealing can be realized between the other end of the sliding sleeve and the second connecting seat; a pushing sleeve 79 made of a metal material is slidably sleeved outside the second connector 72 between the third sealing ring 74 and the sliding sleeve 73, one end of the pushing sleeve 79 is used for abutting against the third sealing ring 74, and the other end of the pushing sleeve 79 is used for abutting against one end of the sliding sleeve 73; after the pushing sleeve made of a metal material is sleeved outside the second connector between the third sealing ring and the sliding sleeve, when the sliding sleeve moves towards one side of the third sealing ring, the sliding sleeve can push the pushing sleeve, and the pushing sleeve can reliably push the third sealing ring.

When the internal expansion type pipeline end part sealing joint is used, firstly, the other end of the second connector and a third sealing ring positioned at the other end of the second connector are inserted into the end part of a pipeline to be measured, then, a compressed air supply pipe inputs compressed air into a second air inlet hole, when the compressed air enters the second air inlet hole, the compressed air can enter a second sealing cavity, at the moment, one end of the sliding sleeve can move towards one side of the third sealing ring and extrude the third sealing ring to enable the third sealing ring to be tightly expanded with the outer wall of the second connector and the inner wall of the pipeline to be measured after being deformed, and at the moment, the second connector and the end part of the pipeline to be measured can be in sealing connection; when the compressed air supply pipe connected with the second air inlet stops supplying compressed air into the second air inlet and the second air inlet is deflated through the air escape valve, the pushing sleeve and the sliding sleeve can slide and reset towards one side far away from the third sealing ring under the action of the resilience force of the third sealing ring, so that the third sealing ring can relieve the expansion with the outer wall of the second connector and the inner wall of the measured pipeline, namely the sealing between the second connector and the measured pipeline can be relieved, and finally the other end of the second connector and the third sealing ring positioned at the other end of the second connector are separated from the end part of the measured pipeline; in addition, the internal expansion type pipeline end sealing joint can be suitable for a tested pipeline with a smaller outer diameter.

When the utility model needs to detect the sealing performance of the detected pipeline, each pair of the third cylinders in the pipeline end sealing connection device can drive the sliding seat to move towards one side of the detected pipeline so as to enable the outer wrapping type pipeline end sealing joint or the inner expanding type pipeline end sealing joint arranged on the sliding seat to be in sealing connection with the end of the detected pipeline on the corresponding position, then the driving end of the second cylinder in each pressure difference detection combined type partition valve drives the second piston to move downwards so as to enable the first sealing ring to realize the plugging of the third vent hole, then the driving end of the first cylinder in each pressure difference detection combined type partition valve drives the first piston to move upwards so as to enable the sealing gasket to remove the plugging of one end of the first vent channel and one end of the second vent channel, at the moment, the compressed air from the air inlet pipe can enter the cavity through the air inlet channel, the compressed air entering the cavity can be filled into the corresponding detected pipeline through the first vent channel, and the compressed air entering the cavity can be filled into the corresponding standard pipeline through the second air outlet channel, after the inflation of the tested pipeline and the standard pipeline is finished (generally, the inflation of the tested pipeline and the standard pipeline can be ensured to be finished by adopting a time delay mode), the driving end of the first air cylinder in each pressure difference detection combined type partition valve drives the first piston to move downwards so as to enable the sealing gasket to realize the plugging of one end of the first air outlet channel and one end of the second air outlet channel, at the moment, the air inlet channel, one end of the first air outlet channel and one end of the second air outlet channel are not communicated with each other, then, each air pressure difference detection sensor starts to detect the air pressure difference between the first air outlet channel and the second air outlet channel in the corresponding pressure difference detection combined type partition valve, and if the air pressure difference between the first air outlet channel and the second air outlet channel is smaller than a preset value, if the air pressure difference between the first air outlet channel and the second air outlet channel is larger than a preset value, the detected pipeline is indicated to have the leakage condition (because the standard pipeline does not have the leakage condition), and thus the detected pipeline is unqualified, and the unqualified detected pipeline can be placed in an unqualified area in the subsequent working process of the pipeline air-tightness detection device; after the detection is finished, the second air cylinder in each differential pressure detection combined type isolating valve can drive the second piston to move upwards, when the second piston moves upwards, the first sealing ring can remove the blockage of the third vent hole, at the moment, the compressed air filled in the tested pipeline can be discharged through the first air outlet channel, the third vent hole, the second valve seat, the exhaust joint and the air blowing pipe in sequence, thus, the compressed air blown out by the air blowing pipe can realize the blowing of the metal scraps in the pipeline end chamfering mechanism, the compressed air is recycled to achieve the purpose of energy conservation, and finally, the two third air cylinders in each pair of pipeline end sealing connecting devices can drive the sliding seat to move towards one side far away from the measured pipeline so that the outer wrapping type pipeline end sealing joint or the inner expanding type pipeline end sealing joint arranged on the sliding seat is separated from the end part of the measured pipeline at the corresponding position; after the detected pipeline air tightness detection is completed, the manipulator can place the detected pipeline which is qualified in detection into a qualified area, and can place the detected pipeline which is unqualified into an unqualified area.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A pipeline airtightness detection apparatus is characterized in that: the device comprises a rack (1), a plurality of differential pressure detection combined type isolating valves (2) and a plurality of differential pressure detection sensors, wherein the differential pressure detection combined type isolating valves (2) and the differential pressure detection sensors are respectively in one-to-one correspondence with each pipeline (3) to be detected, and standard pipelines (4) which are in one-to-one correspondence with each pipeline (3) to be detected are fixed on the rack (1); a plurality of pairs of pipeline end part sealing and connecting devices are installed on the rack (1), two pipeline end part sealing units in each pair of pipeline end part sealing and connecting devices are respectively installed on the rack (1) at the positions of two end parts of a corresponding pipeline (3) to be detected, each pipeline end part sealing unit is used for being in sealing connection with one end of the pipeline (3) to be detected at the corresponding position, one pipeline end part sealing unit in each pair of pipeline end part sealing and connecting devices is used for plugging one end of the pipeline (3) to be detected, the other pipeline end part sealing unit in each pair of pipeline end part sealing and connecting devices is connected with a first air outlet channel in a corresponding differential pressure detection combined type isolating valve (2), one end of each standard pipeline (4) is plugged, and the other end of each standard pipeline (4) is connected with a second air outlet channel in the corresponding differential pressure detection combined type isolating valve (2), two air inlet ends of each air pressure difference detection sensor are respectively connected with a first air outlet channel and a second air outlet channel in the corresponding pressure difference detection combined type isolating valve (2).

2. The piping airtightness detection apparatus according to claim 1, wherein each of the differential pressure detection combined block valves (2) includes a base (21), a first valve seat (22), a first cylinder (23), and a first piston (24); the lower end of the first valve seat (22) is fixed on the base (21), a first sealing structure is arranged between the lower end of the first valve seat (22) and the base (21), a cavity (25) is formed between the first valve seat (22) and the base (21), the first air cylinder (23) is fixed at the upper end of the first valve seat (22), the first piston (24) can vertically penetrate through the first valve seat (22) in a sliding mode, the lower end of the first piston (24) extends into the cavity (25), a second sealing structure is arranged between the first piston (24) and the first valve seat (22), the upper end of the first piston (24) is connected with the driving end of the first air cylinder (23), an air inlet channel (211), a first air outlet channel (212) and a second air outlet channel (213) are arranged in the base (21), one end of the air inlet channel (211) is connected with the driving end of the first air cylinder (23), and the other end of the air outlet channel (211) is connected with the air inlet channel(s), One end of a first air outlet channel (212) and one end of a second air outlet channel (213) are both communicated with a cavity (25), the other end of the air inlet channel (211) is used for being connected with an air inlet pipe, the other end of the first air outlet channel (212) is used for being connected with another pipe end sealing unit in a corresponding pipe end sealing connecting device, the other end of the second air outlet channel (213) is used for being connected with the other end of a corresponding standard pipe (4), a sealing gasket (241) is embedded at the lower end of a first piston (24), a first air cylinder (23) drives the first piston (24) to move downwards, the sealing gasket (241) is used for abutting against the upper end face of a base (21) and used for sealing one end of the first air outlet channel (212) and one end of the second air outlet channel (213), and a first vent hole (214) and a second vent hole (215) are further arranged on the base (21), one end of the first vent hole (214) and one end of the second vent hole (215) are respectively communicated with the first air outlet channel (212) and the second air outlet channel (213), the other end of the first vent hole (214) is used for being connected with one air inlet end of the corresponding air pressure difference detection sensor, and the other end of the second vent hole (215) is used for being connected with the other air inlet end of the corresponding air pressure difference detection sensor.

3. The pipe airtightness detection apparatus according to claim 2, wherein an outer edge of one end of the first gas outlet channel (212) and an outer edge of one end of the second gas outlet channel (213) each protrude from an upper end face of the base (21); the first sealing structure comprises a first sealing ring (221), an annular boss (222) is arranged on the lower end face of the first valve seat (22), a first annular groove (216) is arranged on the upper end face of the base (21), the first sealing ring (221) is embedded in the first annular groove (216), the annular boss (222) is inserted in the first annular groove (216) and used for pressing the first sealing ring (221), and the first sealing ring (221), the first annular groove (216) and the annular boss (222) are tightly sealed; the second sealing structure comprises a plurality of second sealing rings (242) distributed along the axial direction of the first piston (24), first annular embedding grooves (243) which are in one-to-one correspondence with the second sealing rings (242) are formed in the outer wall of the first piston (24), each second sealing ring (242) is embedded in the corresponding first annular embedding groove (243), and each second sealing ring (242) is tightly attached and sealed with the inner wall of the first valve seat (22) and the corresponding first annular embedding groove (243); the upper end of the first piston (24) is provided with a T-shaped clamping groove (244), the driving end of the first air cylinder (23) is provided with a T-shaped clamping block (231), and the clamping block (231) is matched and clamped with the clamping groove (244).

4. The pipeline airtightness detection apparatus according to claim 2 or 3, wherein the differential pressure detection combined type block valve (2) further comprises a second valve seat (26), a second cylinder (27), and a second piston (28), a lower end of the second valve seat (26) is fixed on the base (21), the second cylinder (27) is fixed with an upper end of the second valve seat (26), the second piston (28) is vertically slidably installed in the second valve seat (26), an upper end of the second piston (28) is fixed with a driving end of the second cylinder (27), a lower end of the second piston (28) is provided with an insert rod (281) having an outer diameter smaller than that of the second piston (28), a first seal ring (282) is sleeved outside the insert rod (281), a third vent hole (217) is provided in the base (21), one end of the third vent hole (217) is communicated with the first vent channel (212), after the second piston (28) is driven by the second cylinder (27) to move downwards, the lower end of the inserting rod (281) is used for being inserted into the other end of the third vent hole (217), the first sealing ring (282) is used for abutting against the upper end face of the base (21) and sealing the third vent hole (217), the side wall of the second valve seat (26) is connected with an exhaust joint (261), after the second piston (28) is driven by the second cylinder (27) to move upwards, the exhaust joint (261) is used for being communicated with the third vent hole (217) through the second valve seat (26); the outer edge of the other end of the third vent hole (217) protrudes out of the upper end face of the base (21).

5. The pipeline airtightness detection apparatus according to claim 4, wherein a fourth air vent (218) is further provided in the base (21), one end of the fourth air vent (218) is communicated with the first air outlet channel (212), and the other end of the fourth air vent (218) is used for connecting with a barometer.

6. The pipeline airtightness detection apparatus according to claim 2, wherein each of the pipeline end sealing units includes a sliding seat (51) and a third cylinder (52), the sliding seat (51) is slidably connected to the machine frame (1) via a slide rail assembly (53), the third cylinder (52) is fixed to the machine frame (1), the sliding seat (51) is fixed to a piston rod of the third cylinder (52), each of the pipeline end sealing units further includes an outer wrapping pipeline end sealing joint (6) or an inner expanding pipeline end sealing joint (7) fixed to an inner end face of the sliding seat (51), the third cylinder (52) is configured to drive the sliding seat (51) to move in an axial direction of the pipeline (3) to be tested so that the outer wrapping pipeline end sealing joint (6) or the inner expanding pipeline end sealing joint (7) approaches or moves away from the pipeline (3) to be tested, when the outer wrapping type pipeline end sealing joint (6) or the inner expanding type pipeline end sealing joint (7) is close to the tested pipeline (3), the outer wrapping type pipeline end sealing joint (6) or the inner expanding type pipeline end sealing joint (7) is used for being in sealing connection with the end of the tested pipeline (3); one outer-wrapping type pipeline end sealing joint (6) or inner-expanding type pipeline end sealing joint (7) of each pair of pipeline end sealing connecting devices is used for plugging one end of the tested pipeline (3), and the other outer-wrapping type pipeline end sealing joint (6) or inner-expanding type pipeline end sealing joint (7) of each pair of pipeline end sealing connecting devices is connected with a first air outlet channel (212) of the corresponding differential pressure detection combined type isolating valve (2).

7. The pipe air-tightness detection device according to claim 6, characterized in that said overwrapped pipe end sealing joint (6) comprises a first connection seat (61), a first connection joint (62), a third piston (63) and a set of sealing rings (64); a sliding cavity (611) is arranged inside one end of the first connecting seat (61), the third piston (63) is slidably mounted in the sliding cavity (611), a third sealing structure is arranged between the third piston (63) and the sliding cavity (611), a protruding part (631) with the outer diameter smaller than that of the third piston (63) is integrally formed at one end of the third piston (63), a concave cavity (612) for the protruding part (631) to insert and slide is arranged inside the other end of the first connecting seat (61), a fourth sealing structure is arranged between the protruding part (631) and the concave cavity (612), one end of the first connecting seat (62) is inserted into the sliding cavity (611), an annular convex edge (621) is arranged on the outer wall of the other end of the first connecting seat (62), the annular convex edge (621) is fixed with the end part of one end of the first connecting seat (61), and a first annular step (622) is arranged on the inner wall of one end of the first connecting seat (62), the sealing ring group (64) is embedded in the first annular step (622) and is abutted against the first annular step (622), the other end of the third piston (63) is inserted into the first annular step (622) and is used for extruding the sealing ring group (64) when the third piston (63) moves towards one side of the first connecting head (62), an insertion hole (623) for inserting one end of the measured pipeline (3) is arranged in the first connecting head (62), the other end of the third piston (63) is provided with an insertion groove (632) for inserting one end of the measured pipeline when the third piston (63) moves towards one side of the first connecting head (62), the other end of the first connecting seat (61) is provided with an inflation hole (613), an air guide channel (633) which penetrates through the protruding part (631) and the third piston (63) and is used for communicating the inflation hole (613) with the insertion hole (623) is arranged in the protruding part (631), a first sealing cavity (65) in an annular shape is formed between the third sealing structure and the fourth sealing structure, a first air inlet hole (614) is arranged in the first connecting seat (61), one end of the first air inlet hole (614) is communicated with the first sealing cavity (65), the other end of the first air inlet hole (614) forms a first air inlet (615), when compressed air enters the first air inlet (615), the third piston (63) is used for moving towards one side of the first connecting head (62) and pressing the sealing ring group (64) to enable the sealing ring group (64) to be expanded and tightened with the inner wall of the first connecting head (62) and the outer wall of the tested pipeline (3) after deformation, the air inlet pressure of the first air inlet (615) is larger than the air inlet pressure of the air filling hole (613), the air filling hole (613) in one of the outer wrapping type pipeline end sealing joints (6) in each pair of pipeline end sealing joints is sealed by a plug, the gas filling hole (613) in the other outer wrapping type pipeline end sealing joint (6) in each pair of pipeline end sealing connecting devices is connected with the first gas outlet channel (212) in the corresponding differential pressure detection combined type isolating valve (2).

8. The pipe airtightness detection apparatus according to claim 7, wherein an annular rib (634) is provided on an end surface of the other end of the third piston (63), the annular rib (634) being adapted to abut against the seal ring group (64) and press the seal ring group (64); a support ring (66) which is made of metal materials and is used for allowing one end of a measured pipeline to penetrate through is embedded between the inner bottom of the first annular step (622) and the sealing ring group (64), one side of the support ring (66) is abutted against the inner bottom of the first annular step (622), the other side of the support ring (66) is abutted against the sealing ring group (64), and the support ring (66) is used for supporting the sealing ring group (64); the sealing ring group (64) comprises a plurality of coaxially arranged second sealing rings (641), the plurality of second sealing rings (641) are embedded in the first annular step (622), and every two adjacent second sealing rings (641) are abutted against each other; the third sealing structure comprises a third sealing ring (67), a second annular caulking groove (635) is formed in the outer wall of the third piston (63), the third sealing ring (67) is embedded in the second annular caulking groove (635), and the third sealing ring (67), the second annular caulking groove (635) and the inner wall of the sliding cavity (611) are tightly attached and sealed; a fifth air vent (616) is formed in the side wall of the first connecting seat (61), and the fifth air vent (616) is used for being communicated with a sliding cavity (611) between the third sealing ring (67) and the first connecting head (62); the fourth sealing structure comprises a fourth sealing ring (68) and a fifth sealing ring (69), a third annular caulking groove (636) and a fourth annular caulking groove (637) are formed in the outer wall of the protruding portion (631), the third annular caulking groove (636) and the fourth annular caulking groove (637) are distributed along the axial direction of the protruding portion (631), the fourth sealing ring (68) and the fifth sealing ring (69) are respectively embedded in the third annular caulking groove (636) and the fourth annular caulking groove (637), the inner walls of the fourth sealing ring (68), the third annular caulking groove (636) and the cavity (612) are tightly sealed, and the inner walls of the fifth sealing ring (69), the fourth annular caulking groove (637) and the cavity (612) are tightly sealed; a second annular groove (638) is formed in the outer wall of the projection (631) between the third annular caulking groove (636) and the fourth annular caulking groove (637), a sixth vent hole (617) is formed in the side wall of the first connecting seat (61), and the sixth vent hole (617) is used for being communicated with the second annular groove (638); a plurality of arc-shaped holes (624) which are uniformly distributed in the circumferential direction are formed in the annular convex edge (621), threaded holes (618) which correspond to the arc-shaped holes (624) one to one are formed in the end portion of one end of the first connecting seat (61), small hole diameter portions (6241) are formed in one end of each arc-shaped hole (624), a large hole diameter portion (6242) is formed in the other end of each arc-shaped hole (624), the first connecting head (62) is fixed with the first connecting seat (61) through bolts which penetrate through the small hole diameter portions (6241) and are in threaded connection with the threaded holes (618), the inner diameter of each small hole diameter portion (6241) is larger than the outer diameter of the screw portion of each bolt and smaller than the outer diameter of the head of each bolt, and the inner diameter of each large hole diameter portion (6242) is larger than the outer diameter of the head of each bolt; the inner wall of one end, away from the first annular step (622), of the insertion hole (623) is provided with an annular conical surface (6231), and the annular conical surface (6231) is used for being matched and guided with the end of the measured pipeline (3) so that the end of the measured pipeline (3) can be inserted into the insertion hole (623) and penetrates through the insertion hole (623).

9. The pipe air-tightness detecting apparatus according to claim 6, wherein said expanding-in pipe end sealing joint (7) comprises a second coupling seat (71), a second coupling head (72), a sliding sleeve (73) and a third sealing ring (74); a seventh vent hole (711) is formed in the second connecting seat (71), an eighth vent hole (721) is coaxially formed in the second connecting head (72), one end of the second connecting head (72) is inserted into the second connecting seat (71) and fixed with the second connecting seat (71), a fifth sealing structure is arranged between one end of the second connecting head (72) and the second connecting seat (71), the other end of the second connecting head (72) is used for being inserted into one end of the measured pipeline (3), one end of the seventh vent hole (711) is communicated with one end of the eighth vent hole (721), and an inflation port (712) is formed at the other end of the seventh vent hole (711); a second annular step (722) is arranged on the outer wall of the other end of the second connector (72), and the third sealing ring (74) is sleeved outside the other end of the second connector (72) and abuts against the second annular step (722); one end of the sliding sleeve (73) is slidably sleeved outside the second connector (72) and a sixth sealing structure is arranged between the sliding sleeve (73) and the second connector (72), the other end of the sliding sleeve (73) is slidably sleeved outside the second connecting seat (71) and a seventh sealing structure is arranged between the sliding sleeve (73) and the second connecting seat (71); the fifth sealing structure, the sixth sealing structure and the seventh sealing structure enclose a ring-shaped second sealing cavity (75), a second air inlet hole (713) is formed in the second connecting seat (71), one end of the second air inlet hole (713) is communicated with the second sealing cavity (75), a second air inlet (714) is formed at the other end of the second air inlet hole (713), and when compressed air enters the second air inlet (714), one end of the sliding sleeve (73) is used for moving towards one side of the third sealing ring (74) and extruding the third sealing ring (74) to enable the third sealing ring (74) to deform and then expand tightly with the outer wall of the second connecting head (72) and the inner wall of the pipeline to be tested (3); the air inlet pressure of the second air inlet (714) is larger than the air inlet pressure of the air charging port (712), the air charging port (712) in one inward-expanding type pipeline end sealing joint (7) in each pair of pipeline end sealing connecting devices is sealed by a plug, and the air charging port (712) in the other inward-expanding type pipeline end sealing joint (7) in each pair of pipeline end sealing connecting devices is connected with the first air outlet channel (212) in the corresponding differential pressure detection combined type isolating valve (2).

10. The pipeline airtightness detection apparatus according to claim 9, wherein one end of the second connector (72) is coaxially provided with a threaded joint (723) having an outer diameter smaller than that of the second connector (72), an inner wall of the second connection seat (71) is provided with an internal thread (715), and the threaded joint (723) is threadedly connected with the internal thread (715); a hexagonal countersunk head part (724) is arranged on the inner wall of the other end of the second connector (72); an annular chamfer surface (725) which is used for being matched with the inner wall of the measured pipeline (3) to guide so that the other end of the second connector (72) can be inserted into the measured pipeline (3) is arranged on the outer wall of the other end of the second connector (72); the fifth sealing structure comprises a sixth sealing ring (76), a fifth annular caulking groove (726) is formed in the outer wall of one end of the second connector (72), the sixth sealing ring (76) is embedded in the fifth annular caulking groove (726), and the sixth sealing ring (76), the fifth annular caulking groove (726) and the second connecting seat (71) are tightly attached and sealed; the sixth sealing structure comprises a seventh sealing ring (77), a sixth annular caulking groove (731) is formed in the inner wall of one end of the sliding sleeve (73), the seventh sealing ring (77) is embedded in the sixth annular caulking groove (731), and the seventh sealing ring (77), the sixth annular caulking groove (731) and the outer wall of the second connector (72) are tightly attached and sealed; the seventh sealing structure comprises an eighth sealing ring (78), a seventh annular caulking groove (716) is formed in the outer wall of the second connecting seat (71), the eighth sealing ring (78) is embedded in the seventh annular caulking groove (716), and the eighth sealing ring (78), the seventh annular caulking groove (716) and the inner wall of the other end of the sliding sleeve (73) are tightly attached and sealed; an ejector sleeve (79) made of metal materials is slidably sleeved outside the second connector (72) positioned between the third sealing ring (74) and the sliding sleeve (73), one end of the ejector sleeve (79) is used for abutting against the third sealing ring (74), and the other end of the ejector sleeve (79) is used for abutting against one end of the sliding sleeve (73).