CN117030136A - Pump body pressure maintaining equipment and method - Google Patents

Abstract

The invention discloses pump body pressure maintaining equipment and a pump body pressure maintaining method, and relates to the field of pump body detection, wherein the equipment comprises a rack, and an equipment platform is arranged on the rack and used for installing a water tank; the sealing base is fixed on the water tank and used for positioning the lower end face of the workpiece to be measured; the water supply system is respectively communicated with a water outlet and a water injection port which are formed in the water tank and used for controlling water injection and water drainage of the water tank; the support component is arranged in the sealing base and used for supporting a workpiece to be tested; the inlet sealing cylinder is arranged above the inlet of the workpiece to be tested and is used for compressing the inlet to enable the lower end face to be sealed relative to the sealing base; and the inflation assembly is fixed on the water tank and is used for compressing and sealing an outlet of the workpiece to be tested and simultaneously inflating compressed air into the inner cavity of the workpiece to be tested. The pressure maintaining method comprises the following steps: sealing, pressure maintaining test and drainage. According to the invention, the cylinder is adopted for plugging and sealing, so that the time is saved compared with manual screw thread sealing; when the gas is pressurized, the leakage condition is observed in the liquid, and the leakage effect is more obvious than that observed by the water pressure.

Description

Pump body pressure maintaining equipment and method

Technical Field

The invention relates to the field of pump body detection, in particular to pump body pressure maintaining equipment and method.

Background

In the prior art, after the pump body is machined, leakage detection can be carried out on the pump body, and water injection and pressure maintaining detection or barometer pressure difference detection can be carried out. When the water pressure is adopted in the pump body part, the pressure is maintained, the pressure is required to be high, the time is long, and when the water pressure is low, the slight leakage point (water drop sweat) is not easy to observe; in addition, for the pump body part with multiple holes, the sealing plugs are required to be manually installed on part of the holes, so that the detection efficiency is low. If the pressure difference detection of the barometer is adopted, specific leakage points cannot be found in the observation, and the detection is not easy to find for slight leakage.

In addition, there is the size deviation usually after the pump body part processing, when pump body part put into pressurize (sealing) equipment, because the size cooperation deviation, the difficult problem of part taking in the pressurize process can appear, leads to detection efficiency low, influences follow-up processing. Moreover, the punched pump body is easy to bear pressure in pressure maintaining, so that the pump body is deformed, even damaged, and the workpiece is scrapped.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides pump body pressure maintaining equipment and a pump body pressure maintaining method, wherein the sealing is sealed by adopting an air cylinder seal, so that the time is saved compared with manual screw thread sealing; when the gas is used for maintaining pressure, the leakage condition is observed in the liquid, and the leakage effect is more obvious than that of the water pressure observation; the water is pumped by adopting a large-flow pump, so that the water inlet and water discharge time before and after pressure maintaining of single part can be greatly reduced; the cellular water injection and drainage can greatly reduce the influence of water fluctuation on the pressure maintaining observation of the parts; the whole part pressure maintaining test link is mechanically operated except for observing leakage, taking and one-key operation, so that the standardization and stability of the pressure maintaining process of the workpiece to be tested are ensured.

The invention aims at being completed by the following technical scheme: this kind of pump body pressurize equipment includes:

the rack is provided with an equipment platform for installing a pool;

the sealing base is fixed on the water tank and used for positioning the lower end face of the workpiece to be measured;

the water supply system is respectively communicated with a water outlet and a water injection port which are formed in the water tank and is used for controlling water injection and water drainage of the water tank;

the support component is arranged in the sealing base and used for supporting a workpiece to be tested;

the inlet sealing cylinder is arranged above the inlet of the workpiece to be tested and is used for compressing the inlet and sealing the lower end face relative to the sealing base; and

and the inflation assembly is fixed on the water tank and is used for selectively pressing and tightly sealing an outlet of the workpiece to be tested and simultaneously inflating compressed air into the inner cavity of the workpiece to be tested.

As a further technical scheme, the inflation assembly comprises an outlet sealing cylinder fixed on the water tank, an inflation sealing head is arranged on a piston rod of the outlet sealing cylinder, the inflation sealing head is driven by the outlet sealing cylinder to compress the sealing outlet, and compressed air is filled into the inner cavity of the workpiece to be tested.

As a further technical scheme, the device further comprises a gas-discharging sealing cylinder and a water-discharging sealing cylinder, both of which are fixed on the water tank, wherein the gas-discharging sealing cylinder is used for selectively pressing and tightly sealing a gas discharging port of a workpiece to be tested, and the water-discharging sealing cylinder is used for selectively pressing and tightly sealing a water discharging port of the workpiece to be tested.

As a further technical scheme, the supporting component comprises a supporting column and a supporting spring sleeved on the supporting column, the inlet stretches into the inner cavity of the workpiece to be tested to form an inner end face, the supporting spring provides elasticity for the inner end face, and when the inlet sealing cylinder compresses the inlet, the inner end face is propped against the supporting column; a positioning groove is formed in the sealing base and used for being embedded into a positioning protrusion at the lower end of the support column; a central hole is formed in the support column in an axial penetrating mode, the central hole is communicated with a side hole formed in the radial direction of the support column, and when the inner end face abuts against the support column, the inlet is communicated with the inner cavity of the workpiece to be detected through the central hole and the side hole.

As a further technical scheme, a plurality of locating pins are arranged at the matching position of the sealing base and the lower end face along the circumferential direction, and the workpiece to be detected is located.

As a further technical scheme, the water supply system comprises a water tank, a drainage pump, a water injection pump and a water tank, wherein the water tank, the drainage pump, the water injection pump and the water tank are arranged below the equipment platform, the drainage port and the water injection port are respectively communicated with one water tank, the water tank is communicated with the water tank below the drainage port through the drainage pump, and the water tank is communicated with the water tank below the water injection port through the water injection pump; the water outlet and the water injection port are composed of a plurality of water inlet and outlet small holes which are distributed in a honeycomb mode.

The movable door is driven by the air cylinder, is arranged on the taking and placing opening of the rack in a vertically sliding mode and is used for controlling the opening or closing of the taking and placing opening, and the movable door is limited by a moving door limiting block arranged on the equipment platform, so that at least one part of the taking and placing opening is not shielded by the movable door; the movable door is made of transparent materials.

As a further technical scheme, the automatic air charging system further comprises a control console, wherein a button and a PLC (programmable logic controller) are arranged on the control console and are used for manually or automatically controlling the water supply system, the inlet sealing cylinder and the air charging assembly to work.

The pump body pressure maintaining method adopts the pump body pressure maintaining equipment and comprises the following steps:

step one, sealing: starting a control console, lifting a movable door to open a taking and placing opening, placing a workpiece to be tested into a sealing base, positioning the lower end face through a positioning pin, then pressing down an inlet of the workpiece to be tested by an inlet sealing cylinder until the inner end face abuts against a supporting column, and after a certain delay, simultaneously starting an outlet sealing cylinder, a deflation sealing cylinder and a water discharging sealing cylinder to respectively press an outlet, a deflation opening and a water discharging opening of the workpiece to be tested;

step two, pressure maintaining test: the movable door descends to close the taking and placing opening, compressed air is filled into the outlet through the air filling sealing head, meanwhile, the water filling pump fills water into the water tank through the water filling opening until the water quantity is over the inlet of the workpiece to be tested, the water tank is kept for a certain time, whether bubbling phenomenon exists at each welding position of the workpiece to be tested is observed, if bubbling exists, the welding is bad, and if no bubbling exists, the part is qualified;

step three, draining: after the test is finished, the drainage pump is started, water in the water tank is discharged through the drainage port, when the liquid level descends below the sealing base, the outlet sealing cylinder, the air release sealing cylinder and the water release sealing cylinder are simultaneously started to retract, after a certain delay, the inlet sealing cylinder ascends to open the inlet, the workpiece to be tested is sprung up under the action of the supporting spring and is separated from the supporting column, and meanwhile, the movable door ascends to open the taking and placing port, and the workpiece to be tested can be taken out from the sealing base to finish the detection.

As a further technical scheme, in the first step, the delay time is 0.5s; in the second step, the air pressure of the compressed air is 0.4-0.7 Mpa, and the dwell time is 15s; in the third step, the delay time is 0.5s.

The beneficial effects of the invention are as follows:

1. each inlet and outlet of the workpiece (pump body) to be tested is plugged and sealed through an air cylinder, so that time is saved and detection efficiency is improved compared with manual screw thread sealing;

2. when the air is pressurized, the leakage condition is observed in the liquid, the effect is more obvious than that of water pressure leakage (water drop sweat) observation, and slight leakage is easier to find;

3. the spring compression and rebound modes are adopted, so that workpieces to be tested under different tolerances rebound after the testing is finished, and the workpieces are convenient to take;

4. the movable door is controlled by air pressure (air cylinder), so that the manual frequent repeated operation is solved; the limiting block is arranged below the movable door, so that the problem of clamping hands caused by improper operation of equipment is avoided, and the safety of the equipment is improved;

5. the water draining and filling port adopts a plurality of honeycomb small holes, so that the stable rising and stable falling of the liquid level are ensured when the large-flow water pump rapidly fills water, and the adverse effect on observation and equipment caused by severe fluctuation of the liquid level is reduced;

6. the cylindrical pin is arranged on the sealing base to position the workpiece to be measured, so that the positioning problem when the workpiece is placed is solved;

7. the range of the air filling pressure is adjustable, and the pressure grade problem of pressure maintaining requirements of different workpieces is solved.

Drawings

Fig. 1 is a schematic diagram of a front view structure of the present invention.

Fig. 2 is a schematic perspective view of the present invention.

FIG. 3 is a schematic view of the installation structure of the equipment platform and the pool in the invention.

Fig. 4 is a schematic diagram of an installation structure of a water tank and an equipment platform in the present invention.

Fig. 5 is a schematic perspective view of a pool according to the present invention.

Fig. 6 is a schematic diagram of an assembly structure of a support column and a sealing base in the present invention.

Fig. 7 is a schematic view 1 of a structure of a workpiece (pump body) to be measured in the present invention.

Fig. 8 is a schematic view 2 of the structure of a workpiece (pump body) to be measured in the present invention.

Reference numerals illustrate: the water tank comprises an inlet sealing cylinder 1, a water tank 2, a workpiece 3 to be tested, an inlet 3a, an outlet 3b, a gas discharge port 3c, a water discharge port 3d, a lower end surface 3e, an inner end surface 3f, an outlet sealing cylinder 4, an inflatable sealing head 4a, a gas discharge sealing cylinder 5, a water discharge port 6, a sealing base 7, a positioning groove 7a, a sealing ring 7b, a water discharge sealing cylinder 8, a water injection port 9, a control console 10, an equipment platform 11, a moving door 12, a supporting column 13, a central hole 13a, a side hole 13b, a positioning protrusion 13c, a supporting spring 14, a positioning pin 15, a rack 16, a taking and placing port 16a, a water tank 17, a drainage pump 18, a water injection pump 19, a water tank 20, a water baffle 21, a water inlet and outlet small hole 22 and a moving door positioning block 23.

Detailed Description

The invention will be described in detail below with reference to the attached drawings:

examples: as shown in fig. 1 to 8, the pump body pressure maintaining device comprises an inlet sealing cylinder 1, a water tank 2, a workpiece to be measured 3, an inlet 3a, an outlet 3b, a vent 3c, a water drain 3d, a lower end face 3e, an inner end face 3f, an outlet sealing cylinder 4, an inflatable sealing head 4a, a deflation sealing cylinder 5, a water outlet 6, a sealing base 7, a positioning groove 7a, a sealing ring 7b, a water discharge sealing cylinder 8, a water injection port 9, a control console 10, a device platform 11, a movable door 12, a support column 13, a central hole 13a, a side hole 13b, a positioning protrusion 13c, a support spring 14, a positioning pin 15, a rack 16, a taking and placing port 16a, a water tank 17, a drainage pump 18, a water injection pump 19, a water tank 20, a water baffle 21, a water inlet and outlet small holes 22 and a movable door positioning block 23.

Referring to fig. 1 and 2, a rack 16 is disposed outside the apparatus, an apparatus platform 11 is formed in the middle of the rack 16, a pick-and-place opening 16a is disposed on the front of the rack 16 near the apparatus platform 11, and a moving door 12 is disposed on the pick-and-place opening 16a in a sliding manner, and the moving door 12 is driven to lift by an air cylinder and is controlled by the console 10. The movable door 12 can control the opening or closing of the access opening 16a when lifting, preferably, the movable door 12 is limited by a movable door limiting block 23 arranged on the equipment platform 11, so that at least a part of the lower part of the access opening 16a is not shielded by the movable door 12, the problem of clamping hands caused by improper operation of workers is avoided, and the safety of the equipment is improved. Further, the sliding door 12 is made of transparent material (acrylic) so as to facilitate observation of the internal condition of the device.

As shown in fig. 3 and 4, a water tank 2 is installed in the middle of the equipment platform 11, and preferably, a water baffle 21 is installed at the edge of the water tank 2 to prevent the test water from leaking. Further, the sealing base 7 is fixed in the middle of the water tank 2, a supporting component is installed in the sealing base 7 and used for supporting the workpiece 3 to be detected, the lower end face 3e of the workpiece 3 to be detected is positioned on the sealing base 7, and a plurality of positioning pins 15 (shown in fig. 6) are arranged at the matching position of the sealing base 7 and the lower end face 3e along the circumferential direction, so that the workpiece 3 to be detected can be positioned. Referring to fig. 5 and 6, the support assembly includes a support column 13 and a support spring 14 sleeved on the support column 13, as shown in fig. 7 and 8, a portion of the inlet 3a extending into the inner cavity of the workpiece 3 to be measured forms an inner end surface 3f, when the workpiece 3 to be measured is placed on the seal base 7, the support spring 14 contacts with the workpiece 3 to be measured first and provides elastic force to the inner end surface 3f, when the inlet seal cylinder 1 compresses the inlet 3a (the workpiece 3 to be measured), the support spring 14 is compressed, and meanwhile, the inner end surface 3f abuts against the support column 13, so that the workpiece 3 (the pump body) to be measured is not easy to deform when being compressed. Further, a positioning groove 7a is formed in the center of the sealing base 7 and is used for being embedded into a positioning protrusion 13c at the lower end of the mounting support column 13, a central hole 13a is formed in the support column 13 in an axial penetrating mode, the central hole 13a is communicated with a side hole 13b formed along the radial direction of the support column 13, when the inner end face 3f abuts against the support column 13, the inlet 3a is communicated with the inner cavity of the workpiece 3 to be tested through the central hole 13a and the side hole 13b (air pressure balance), the inner cavity cannot be adsorbed by the sealing base 7 and the support column 13 due to water sealing, and meanwhile the fact that the upper portion of the support column 13 (namely the space between the inner end face 3f and the inlet 3 a) is in a pressure maintaining state is guaranteed.

As shown in fig. 3 and 5, the inlet seal cylinder 1 is disposed above the inlet 3a (seal base 7) of the workpiece 3 to be measured, and the inlet seal cylinder 1 is used for pressing the inlet 3a so as to seal the lower end face 3e of the workpiece 3 to be measured against the seal base 7, preferably, as shown in fig. 6, a seal ring 7b is disposed on the seal base 7 inside the positioning pin 15, and can be matched with the lower end face 3e to realize pressing seal.

The outlet sealing cylinder 4 is fixed on the water tank 2, the outlet sealing cylinder 4 can compress and seal the outlet 3b of the workpiece 3 to be tested under the control of the control console 10, the piston rod of the outlet sealing cylinder 4 is provided with an air filling sealing head 4a, one end of the air filling sealing head 4a is externally connected with compressed air, the other end of the air filling sealing head is used for communicating the outlet 3b, and the air filling sealing head 4a compresses the sealing outlet 3b under the drive of the outlet sealing cylinder 4 and fills the compressed air into the inner cavity of the workpiece 3 to be tested. The outlet sealing cylinder 4 and the air filling sealing head 4a form an air filling assembly together. As shown in fig. 7 and 8, the work 3 (pump body) to be measured is provided with a vent port 3c and a water discharge port 3d in addition to the top inlet 3a, the left outlet 3b, and the lower end surface 3 e. Further, the air release sealing cylinder 5 and the water discharge sealing cylinder 8 are both fixed on the water tank 2, wherein the air release sealing cylinder 5 can compress and seal the air release port 3c of the workpiece 3 to be tested under the control of the control console 10, and the water discharge sealing cylinder 8 can compress and seal the water discharge port 3d of the workpiece 3 to be tested under the control of the control console 10. Preferably, buffer sealing gaskets are arranged at the contact positions of the four cylinders of the inlet sealing cylinder 1, the outlet sealing cylinder 4, the air release sealing cylinder 5 and the water release sealing cylinder 8 and the workpiece 3 (pump body) to be tested, so that the air tightness is ensured.

As shown in fig. 3, 4 and 5, a water tank 17, a drainage pump 18, a water injection pump 19, a water tank 20 and a plurality of connecting pipelines are arranged below the equipment platform 11 to form a water supply system together, the lower parts of the drainage port 6 and the water injection port 9 are respectively communicated with one water tank 17, the water tank 20 is communicated with the water tank 17 below the drainage port 6 through the drainage pump 18, and the water tank 20 is communicated with the water tank 17 below the water injection port 9 through the water injection pump 19 to realize water injection and drainage circulation. Preferably, the drainage pump 18 and the water injection pump 19 are large-flow water pumps, the drainage port 6 and the water injection port 9 are composed of a plurality of water inlet and outlet small holes 22 distributed in a honeycomb shape, so that the stable rising and stable falling of the liquid level are ensured when the large-flow water pumps rapidly fill water, and the adverse effects on observation and equipment caused by severe fluctuation of the liquid level are reduced; preferably, a check valve is also arranged on the pipeline of the water injection pump 19 to ensure that the water injection port 9 does not have the condition of water backflow.

Further, as shown in fig. 1 and 2, a console 10 is disposed on the right side of the frame 16, and a plurality of buttons and a PLC controller are disposed on the console 10, so that the operation of the water supply system, the inlet seal cylinder 1, the outlet seal cylinder 4, the air release seal cylinder 5, the water discharge seal cylinder 8 and the air inflation seal head 4a can be manually or automatically controlled by the console 10.

Example 2: the pump body pressure maintaining method adopts the pump body pressure maintaining equipment in the embodiment 1, and comprises the following steps:

step one, sealing: starting the control console 10, automatically lifting the movable door 12 to open the taking and placing opening 16a, placing the workpiece 3 to be tested into the sealing base 7 by an operator, positioning the lower end face 3e through the positioning pin 15, supporting the workpiece 3 to be tested by the supporting spring 14, then starting the inlet sealing cylinder 1 and pressing down the inlet 3a of the workpiece 3 to be tested until the inner end face 3f is propped against the supporting column 13, at the moment, compressing the supporting spring 14 and sealing the lower end face 3e by matching with the sealing ring 7b, and after a certain delay (preferably, the delay time is 0.5 s), starting the outlet sealing cylinder 4, the air discharging sealing cylinder 5 and the water discharging sealing cylinder 8 simultaneously, and respectively pressing the outlet 3b, the air discharging opening 3c and the water discharging opening 3d of the workpiece 3 to be tested, so that all openings of the workpiece 3 to be tested are sealed;

step two, pressure maintaining test: the movable door 12 automatically descends to the position of the movable door limiting block 23, the taking and placing opening 16a is closed, a gap (about 15 cm) is reserved for preventing clamping operators, then compressed air is filled into the outlet 3b (the inner cavity of the workpiece 3 to be tested) through the airtight sealing head 4a (the air pressure of the compressed air is 0.4-0.7 Mpa, the air pressure can be adjusted through an air pressure stabilizing and adjusting valve arranged on the back of the equipment so as to adapt to pressure-maintaining requirement pressure levels of different workpieces), meanwhile, the water injection pump 19 injects water into the water tank 2 through the water injection port 9 until the water quantity is over the inlet 3a of the workpiece 3 to be tested, the water is kept for a certain time (preferably, the pressure-maintaining time is 15 s), and whether bubbling phenomena exist at each welding position of the workpiece 3 to be tested, if bubbling exists, the bubbling is bad, and the non-bubbling indicates that the part is qualified;

step three, draining: after the test is finished, the drainage pump 18 is started to drain water in the water tank 2 through the drainage port 6, when the liquid level is lowered below the sealing base 7, the outlet sealing cylinder 4, the air release sealing cylinder 5 and the water release sealing cylinder 8 are started to retract simultaneously, after a certain delay (the delay time is 0.5 s), the inlet sealing cylinder 1 is lifted to open the inlet 3a, the workpiece 3 to be tested is lifted up under the action of the supporting spring 14 and separated from the supporting column 13, meanwhile, the movable door 12 is lifted up to open the taking and placing port 16a, and an operator can take the workpiece 3 to be tested out of the sealing base 7 to finish the detection.

The invention adopts a mode of combining water and compressed air, and the inspection and observation of the water leakage phenomenon possibly existing in the welded pump shell process are more careful; the sealing treatment of the joint is carried out by adopting polyurethane, rubber and other materials matched with a cylinder in a compacting manner, and the joint can be quickly replaced; the spring compression and rebound modes are adopted, so that workpieces to be tested under different tolerances rebound after the testing is finished, and the workpieces are convenient to take; when the movable door moves, the cylinder movement and limit are adopted, so that the manual operation and the operation safety are reduced; the PLC is adopted for automatic control, and a control mode of combining a button and a touch screen is adopted, so that the operation of the whole equipment is changed into one-key operation; the structure of the acrylic and aluminum alloy frame is adopted, so that observation and water resistance are convenient; the water inlet and the water outlet adopt honeycomb design, so that the stable rising and stable falling of the liquid level are ensured, and the adverse effect of severe fluctuation of the liquid level on observation and equipment is reduced.

The test procedure is summarized as follows:

1, manually loading a pump shell into a tool;

2, in an automatic state, starting a switch button;

3, descending a gate cylinder;

4, the pump shell is pressed by the pressing cylinder;

5 three groups of sealing cylinders extend out simultaneously;

the water injection time for starting the water inlet pump can be set;

7, opening a compressed air test air inlet electromagnetic valve;

8, after water injection of the water inlet pump is completed, the pressure maintaining test time is timed, and the time is adjustable; manually observing whether the air leakage is finished;

9, the water discharge electromagnetic valve is opened, the water discharge pump starts water discharge, and the time can be set;

10, closing a compressed air test electromagnetic valve;

11. three groups of sealing cylinders retract simultaneously;

12. the pump shell is pressed and assembled with the cylinder to ascend and reset;

and (13) lifting and resetting the gate cylinder to finish a set of actions.

It should be understood that equivalents and modifications to the technical scheme and the inventive concept of the present invention should fall within the scope of the claims appended hereto.

Claims (10)

1. The utility model provides a pump body pressurize equipment which characterized in that includes:

a frame (16) on which an equipment platform (11) is arranged for installing the pool (2);

the sealing base (7) is fixed on the water tank (2) and is used for positioning the lower end face (3 e) of the workpiece (3) to be measured;

the water supply system is respectively communicated with a water outlet (6) and a water injection port (9) which are arranged on the water tank (2) and is used for controlling water injection and water drainage of the water tank (2);

the supporting component is arranged in the sealing base (7) and is used for supporting the workpiece (3) to be tested;

the inlet sealing cylinder (1) is arranged above the inlet (3 a) of the workpiece (3) to be tested and is used for compressing the inlet (3 a) and sealing the lower end surface (3 e) relative to the sealing base (7); and

the inflation assembly is fixed on the water tank (2) and is used for selectively pressing and tightly sealing an outlet (3 b) of the workpiece (3) to be tested and simultaneously inflating compressed air into the inner cavity of the workpiece (3) to be tested.

2. Pump body pressure maintaining device according to claim 1, characterized in that: the inflation assembly comprises an outlet sealing cylinder (4) fixed on the water tank (2), an inflation sealing head (4 a) is arranged on a piston rod of the outlet sealing cylinder (4), the inflation sealing head (4 a) compresses a sealing outlet (3 b) under the driving of the outlet sealing cylinder (4), and compressed air is filled into an inner cavity of a workpiece (3) to be tested.

3. Pump body pressure maintaining device according to claim 1, characterized in that: the automatic sealing device is characterized by further comprising a gas discharging sealing cylinder (5) and a water discharging sealing cylinder (8), wherein the gas discharging sealing cylinder (5) and the water discharging sealing cylinder (8) are both fixed on the water tank (2), the gas discharging sealing cylinder (5) is used for selectively pressing and tightly sealing a gas discharging opening (3 c) of the workpiece (3) to be tested, and the water discharging sealing cylinder (8) is used for selectively pressing and tightly sealing a water discharging opening (3 d) of the workpiece (3) to be tested.

4. Pump body pressure maintaining device according to claim 1, characterized in that: the supporting assembly comprises a supporting column (13) and a supporting spring (14) sleeved on the supporting column (13), the inlet (3 a) stretches into the inner cavity of the workpiece (3) to be tested to form an inner end face (3 f), the supporting spring (14) provides elasticity for the inner end face (3 f), and when the inlet sealing cylinder (1) presses the inlet (3 a), the inner end face (3 f) is propped against the supporting column (13); a positioning groove (7 a) is formed in the sealing base (7) and is used for being embedded into a positioning protrusion (13 c) at the lower end of the supporting column (13); a central hole (13 a) is formed in the support column (13) in a penetrating mode along the axial direction, the central hole (13 a) is communicated with a side hole (13 b) formed in the radial direction of the support column (13), and when the inner end face (3 f) abuts against the support column (13), the inlet (3 a) is communicated with the inner cavity of the workpiece (3) to be detected through the central hole (13 a) and the side hole (13 b).

5. Pump body pressure maintaining device according to claim 1, characterized in that: the matching part of the sealing base (7) and the lower end face (3 e) is provided with a plurality of positioning pins (15) along the circumferential direction, and the workpiece (3) to be detected is positioned.

6. Pump body pressure maintaining device according to claim 1, characterized in that: the water supply system comprises a water tank (17), a drainage pump (18), a water injection pump (19) and a water tank (20) which are arranged below the equipment platform (11), wherein the drainage port (6) and the water injection port (9) are respectively communicated with the water tank (17), the water tank (20) is communicated with the water tank (17) below the drainage port (6) through the drainage pump (18), and the water tank (20) is communicated with the water tank (17) below the water injection port (9) through the water injection pump (19); the water outlet (6) and the water injection port (9) are composed of a plurality of water inlet and outlet small holes (22) which are distributed in a honeycomb shape.

7. Pump body pressure maintaining device according to claim 1, characterized in that: the movable door (12) is driven by an air cylinder, is arranged on a picking and placing port (16 a) of the rack (16) in a vertically sliding mode and is used for controlling the picking and placing port (16 a) to be opened or closed, and the movable door (12) is limited by a moving door limiting block (23) arranged on the equipment platform (11), so that at least one part of the picking and placing port (16 a) is not blocked by the movable door (12); the sliding door (12) is made of transparent materials.

8. Pump body pressure maintaining device according to claim 1, characterized in that: the automatic air charging system further comprises a control console (10), wherein a button and a PLC controller are arranged on the control console (10) and are used for manually or automatically controlling the water supply system, the inlet sealing air cylinder (1) and the air charging assembly to work.

9. A pump body pressure maintaining method using the pump body pressure maintaining apparatus according to any one of claims 1 to 8, comprising the steps of:

step one, sealing: starting a control console (10), lifting a movable door (12) to open a taking and placing opening (16 a), placing a workpiece (3) to be tested into a sealing base (7), positioning a lower end face (3 e) through a positioning pin (15), then pressing down an inlet (3 a) of the workpiece (3) to be tested by an inlet sealing cylinder (1) until an inner end face (3 f) abuts against a supporting column (13), and starting an outlet sealing cylinder (4), a deflation sealing cylinder (5) and a water discharging sealing cylinder (8) at the same time after a certain delay, and respectively pressing an outlet (3 b), a deflation opening (3 c) and a water discharging opening (3 d) of the workpiece (3) to be tested;

step two, pressure maintaining test: the movable door (12) descends to close the taking and placing opening (16 a), compressed air is filled into the outlet (3 b) through the air filling sealing head (4 a), meanwhile, the water injection pump (19) injects water into the water tank (2) through the water injection opening (9) until the water quantity is over the inlet (3 a) of the workpiece (3) to be tested, the water tank is kept for a certain time, whether bubbling phenomena exist at each welding position of the workpiece (3) to be tested is observed, if bubbling is bad, the welding is bad, and if no bubbling exists, the part is qualified;

step three, draining: after the test is finished, the drainage pump (18) is started to drain water in the water tank (2) through the drainage port (6), when the liquid level descends below the sealing base (7), the outlet sealing cylinder (4), the air release sealing cylinder (5) and the water release sealing cylinder (8) are started to retract simultaneously, after a certain delay, the inlet sealing cylinder (1) ascends to open the inlet (3 a), the workpiece (3) to be detected is sprung up under the action of the supporting spring (14) and separated from the supporting column (13), and meanwhile, the movable door (12) ascends to open the taking and placing opening (16 a), and the workpiece (3) to be detected can be taken out from the sealing base (7) to finish detection.

10. The pump body pressure maintaining method according to claim 9, characterized in that: in the first step, the delay time is 0.5s; in the second step, the air pressure of the compressed air is 0.4-0.7 Mpa, and the dwell time is 15s; in the third step, the delay time is 0.5s.