CN115371902A - Detection system and method for inner pipe leakage hole of vacuum heat insulation pipeline of test station - Google Patents
Detection system and method for inner pipe leakage hole of vacuum heat insulation pipeline of test station Download PDFInfo
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- CN115371902A CN115371902A CN202210971343.7A CN202210971343A CN115371902A CN 115371902 A CN115371902 A CN 115371902A CN 202210971343 A CN202210971343 A CN 202210971343A CN 115371902 A CN115371902 A CN 115371902A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
- G01M3/22—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators
- G01M3/222—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material for pipes, cables or tubes; for pipe joints or seals; for valves; for welds; for containers, e.g. radiators for tubes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
- G01M3/202—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material using mass spectrometer detection systems
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
- G01M3/202—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material using mass spectrometer detection systems
- G01M3/205—Accessories or associated equipment; Pump constructions
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- Examining Or Testing Airtightness (AREA)
Abstract
The invention relates to a detection system for a leak hole in an inner pipe of a vacuum heat insulation pipeline of a test station, which comprises a vacuum heat insulation pipeline used for transmitting low-temperature liquid generated by a low-temperature refrigerator to a distribution valve box, wherein the vacuum heat insulation pipeline is connected with at least one helium mass spectrometer leak detector; the vacuum heat insulation pipeline is formed by welding a plurality of prefabricated sections through corresponding transition sections, each prefabricated section comprises an inner pipeline, an outer pipeline and a vacuum interlayer between the inner pipeline and the outer pipeline, a vacuum safety plug is arranged on the outer pipeline of each prefabricated section, and at least one prefabricated section is connected with an auxiliary evacuation system. The invention also relates to a method for detecting the inner pipe leak of the vacuum heat-insulating pipeline of the test station. The invention realizes the detection of the inner pipes of the vacuum heat insulation pipeline one by one and in sections, can accurately and quickly determine the inner pipe with the leak hole, quickly and accurately position the range of the leak hole, and improves the detection efficiency and the detection accuracy.
Description
Technical Field
The invention relates to a detection technology of a low-temperature heat-insulation vacuum pipeline, in particular to a detection system and a detection method of an inner pipe leak hole of a vacuum heat-insulation pipeline of a test station, which are used for quickly positioning a weld leak point of an inner pipe.
Background
A low-temperature distribution and transmission system is arranged between the superconducting test platform and the low-temperature system, and comprises a low-temperature valve box and a transmission pipeline. In order to smoothly convey and use the low-temperature fluid and provide a stable 2K experimental environment for a superconducting high-frequency test platform, the total leakage rate of the vacuum heat-insulating pipeline at normal temperature is required to be less than 1.0E -9 Pa·m 3 /s。
The vacuum heat insulation pipeline is formed by assembling a plurality of prefabricated sections on site, the inner pipe comprises hundreds of butt welding seams, the possible leakage rate value is qualified when the installation is finished, but after low-temperature super-flow helium is conveyed for a period of time, the inner pipe can cause material fatigue to cause the tensile fracture of the welding seams due to the fact that the inner pipe is subjected to a plurality of times of cold and heat alternate changes, the leakage phenomenon is caused, and the low-temperature device cannot recycle cooling working media.
In the traditional vacuum helium mass spectrometer leak detection, if a leak hole exists, negative pressure needs to be pumped again and pressure maintaining needs to be continued. This method is time-consuming and does not allow the specific positioning of the leak holes of the inner tube. The helium mass spectrometer leak detection positive pressure method is suitable for detecting leak holes of an outer pipe of a vacuum heat insulation pipeline, all transition sections need to be removed when the inner pipe is the largest, leak detection can be carried out, the workload is large, and the operation time is long. As the problem of leakage hole can not be solved, the pipelines with value of tens of millions are always scrapped. Therefore, it is necessary to develop a quick and effective leak detection scheme to determine the position of the inner pipe leak hole so as to timely remedy when the equipment is shut down, so that the vacuum heat insulation pipeline reaches the normal use level, and the huge loss of a low-temperature system is avoided.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a system and a method for detecting the inner pipe leakage hole of the vacuum heat insulation pipeline of the test station, which can realize the quick and accurate positioning of the inner pipe leakage hole of the vacuum heat insulation pipeline.
The invention provides a detection system for a leak hole in an inner pipe of a vacuum heat insulation pipeline of a test station, which comprises the vacuum heat insulation pipeline used for transmitting low-temperature liquid generated by a low-temperature refrigerator to a distribution valve box, wherein the vacuum heat insulation pipeline is connected with at least one helium mass spectrometer leak detector; the vacuum heat insulation pipeline is formed by welding a plurality of prefabricated sections through corresponding transition sections, each prefabricated section comprises an inner pipeline, an outer pipeline and a vacuum interlayer between the inner pipeline and the outer pipeline, a vacuum safety plug is arranged on the outer pipeline of each prefabricated section, and at least one prefabricated section is connected with an auxiliary evacuation system.
Further, the vacuum safety plug is provided with a matched safety plug tool, and the helium mass spectrometer leak detector is connected with the safety plug tool in a sealing mode through a corrugated pipe.
Further, the diameter of the bellows is the same as the diameter of the exhaust port of the helium mass spectrometer leak detector.
Further, the corrugated pipe is in the form of a stainless steel corrugated pipe KF interface.
Further, the auxiliary evacuation system comprises a first vacuum unit acting on the vacuum interlayer and a second vacuum unit acting on the inner conduit.
Furthermore, the first vacuum unit comprises a vacuum valve and a first vacuum pump group which are sequentially connected with the vacuum interlayer through a first air exhaust branch, a vacuum gauge is connected on a section of first air exhaust branch between the vacuum interlayer and the vacuum valve, and a nitrogen storage tank is connected on a section of first air exhaust branch between the vacuum valve and the first vacuum pump group.
Further, the vacuum gauge is connected to the first branch of bleeding through the angle valve, first nitrogen gas storage tank is connected to the first branch of bleeding through nitrogen gas supply branch road, just be equipped with manometer and block valve on the nitrogen gas supply branch road.
Furthermore, the second vacuum unit comprises a plurality of inner pipe branches respectively connected with the inner pipelines, and the inner pipe branches are connected with the second vacuum pump set through a second air exhaust branch, connected with the recovery air bag through a helium recovery branch and connected with the helium storage tank through a helium supply branch.
Further, a pump switching valve is arranged on the second air exhaust branch, an air bag on-off valve is arranged on the helium recovery branch, a storage tank on-off valve is arranged on the helium supply branch, and an inner pipe process valve is arranged on the inner pipe branch.
The invention also provides a method for detecting the inner pipe leak of the vacuum heat insulation pipeline of the test station, which comprises the following steps:
step S1, providing a detection system for the inner pipe leakage hole of the vacuum heat insulation pipeline of the test station;
s2, starting a second vacuum pump set of a second vacuum unit, and evacuating the inner pipeline of the vacuum heat insulation pipeline to below 5 Pa;
s3, closing the second vacuum pump group, opening a first vacuum pump group and a nitrogen storage tank of a first vacuum unit, performing nitrogen replacement on a vacuum interlayer of the vacuum heat insulation pipeline for a plurality of times, evacuating to below 5Pa each time, and cleaning helium impurities remained in the vacuum interlayer;
s4, closing the first vacuum pump group and the nitrogen storage tank, communicating the vacuum heat insulation pipeline with a helium mass spectrometer leak detector, performing vacuum negative pressure leak detection on an inner pipeline of the vacuum heat insulation pipeline, and determining the inner pipeline with a leak hole;
s5, carrying out vacuum negative pressure leak detection on each transition section corresponding to the internal pipeline with the leak hole, and determining the transition section of the internal pipeline with the leak hole;
s6, starting the nitrogen storage tank, filling nitrogen into a vacuum interlayer of the vacuum heat insulation pipeline, and removing a shell of a transition section where the leakage hole is located;
and S7, starting a helium storage tank, filling helium into the internal pipeline with the leak holes of the vacuum heat insulation pipeline, surrounding all or part of the transition section of the internal pipeline with the leak holes by using a helium cover, and determining the real leak points by using a suction gun mode of the helium mass spectrometer leak detector.
The system and the method for detecting the leak holes in the inner pipe of the vacuum heat insulation pipeline of the test station realize the detection of the inner pipe of the vacuum heat insulation pipeline one by one and in a segmented manner, can accurately and quickly determine the inner pipe with the leak holes, quickly and accurately position the range of the leak holes, and improve the detection efficiency and the detection accuracy.
Drawings
FIG. 1 is a schematic diagram of a test system for detecting leaks in pipes in a vacuum insulated pipeline of a test station according to the present invention.
Fig. 2 is a schematic view showing the structure of an inner pipe of the vacuum insulation line of fig. 1.
FIG. 3 is an explanatory view showing leak detection by the method for detecting a leak in a piping in a vacuum insulated line of a test station according to the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
As shown in fig. 1, the present invention provides a system for detecting a leak in a vacuum insulated pipeline of a test station, which includes a vacuum insulated pipeline 3 for transferring cryogenic liquid generated by a cryocooler 1 to a distribution valve box 2, wherein the vacuum insulated pipeline 3 is connected to at least one helium mass spectrometer leak detector 4. The vacuum heat insulation pipeline 3 is formed by welding a plurality of prefabricated sections 31 through corresponding transition sections 32 (namely, the long-distance vacuum heat insulation pipeline 3 is formed by welding a plurality of short-distance prefabricated sections 31 on site, each transition section 32 is used as a connecting section when each prefabricated section 31 is welded on site), each prefabricated section 31 comprises a plurality of inner pipelines, an outer pipeline and a vacuum interlayer between the inner pipeline and the outer pipeline, the outer pipeline of each prefabricated section 31 is provided with a vacuum safety plug 5 with the same specification, and at least one prefabricated section 31 is connected with an auxiliary evacuation system. It will be appreciated that the inner and outer conduits of adjacent pre-fabricated sections 31 are all in communication to form the complete vacuum insulated pipeline 3.
The vacuum safety plug 5 of each prefabricated section 31 is provided with a matched safety plug tool to control the connection and disconnection of the vacuum heat insulation pipeline 3 and an external device and/or system, and the helium mass spectrometer leak detector 4 is connected with the safety plug tools in a sealing mode through a corrugated pipe. The diameter of the bellows is the same as the diameter of the exhaust port of the helium mass spectrometer leak detector 4 and in this embodiment the bellows takes the form of a stainless steel bellows KF interface. It should be noted that if a certain prefabricated section is subjected to leak detection, the vacuum heat insulation pipeline 3 only needs to be connected with one helium mass spectrometer leak detector; if a certain transition section is subjected to leak detection, the vacuum heat insulation pipeline 3 needs to be connected with two helium mass spectrometer leak detectors; when two helium mass spectrometer leak detectors are connected, the corrugated pipes used are of the same specification.
The auxiliary evacuation system has the functions of pre-vacuumizing, gas diversion, reduction of the reaction time and the clearing time of the leakage-indicating gas and the like, and has the function of accelerating the rhythm of leakage detection, and comprises a first vacuum unit 61 acting on a vacuum interlayer and a second vacuum unit 62 acting on an inner pipeline (see fig. 2).
The first vacuum unit 61 comprises a vacuum valve 612 and a first vacuum pump group 613 which are sequentially connected with the vacuum interlayer through a first pumping branch 611, and a vacuum gauge 614 is connected to a section of the first pumping branch 611 between the vacuum interlayer and the vacuum valve 612 and is used for monitoring the vacuum pressure in the vacuum interlayer; and a section of the first pumping branch 611 between the vacuum valve 612 and the first vacuum pump group 613 is connected with a nitrogen storage tank 615 for charging nitrogen into the vacuum interlayer. The vacuum gauge 614 is connected to the first pumping branch 611 through an angle valve 616, the nitrogen storage tank 615 is connected to the first pumping branch 611 through a nitrogen supply branch 617, and a pressure gauge 618 for monitoring real-time supply pressure and an isolating valve 619 for controlling on-off of a pipeline are arranged on the first nitrogen supply branch 617.
As shown in fig. 2 (a to E show 5 inner pipes in the vacuum heat insulation line), the second vacuum unit 62 includes a plurality of inner pipe branches 33 connected to the respective inner pipes, and the inner pipe branches 33 are connected to the second vacuum pump group 622 through the second pumping branch 621, connected to the recovery gas bag 624 through the helium recovery branch 623, and connected to the helium storage tank 626 through the helium supply branch 625. The recovery gas bag 624 recovers helium in the internal pipe through the helium recovery branch 623, and the helium storage 626 charges helium into the internal pipe through the helium supply branch 625. And, a pump switching valve 627 is disposed on the second pumping branch 621 for controlling the connection and disconnection between the second vacuum pump set 622 and all internal pipelines. An air bag on-off valve 628 is arranged on the helium recovery branch 623 and is used for controlling the on-off of the recovery air bag 624 and all internal pipelines. A storage tank on-off valve 629 is provided on the helium supply branch 625 for controlling the on-off of the helium storage tank 626 and all internal pipes. In addition, each inner pipe branch 33 is provided with an inner pipe process valve 34 for controlling the independent on-off of each inner pipe branch 33.
The leak rates of all the lines and the connecting portions of the helium mass spectrometer leak detector 4 and the auxiliary evacuation system are less than 1.0E -9 Pa·m 3 /s。
Based on the detection system, the invention also provides a method for detecting the inner pipe leak of the vacuum heat insulation pipeline of the test station, which comprises the following steps:
step S1, providing the detection system for the inner pipe leakage hole of the vacuum heat insulation pipeline of the test station.
In step S2, the second vacuum pump group 622 of the second vacuum unit 62 is started to evacuate the inner pipe of the vacuum heat insulation line 3 to below 5 Pa.
And S3, closing the second vacuum pump unit 622, starting the first vacuum pump unit 613 and the nitrogen storage tank 615 of the first vacuum unit 61, performing nitrogen replacement on the vacuum interlayer of the vacuum heat insulation pipeline 3 for a plurality of times, evacuating to below 5Pa each time, and cleaning residual helium impurities in the vacuum interlayer.
And S4, closing the first vacuum pump group 613 and the nitrogen storage tank 615, communicating the vacuum heat insulation pipeline 3 with the helium mass spectrometer leak detector 4, performing vacuum negative pressure leak detection on the inner pipeline of the vacuum heat insulation pipeline 3, and determining the inner pipeline with a leak hole.
Step S4 specifically includes:
step S41, connecting a helium mass spectrometer leak detector 4 to a vacuum safety plug on an external pipeline, operating the helium mass spectrometer leak detector 4, and waiting for the background leak rate of the helium mass spectrometer leak detector 4 to be stable;
step S42, helium is sequentially filled into each internal pipeline by using a helium storage tank 626, the leakage rate value of the helium mass spectrometer leak detector 4 is observed after the helium is filled, and if the leakage rate value exceeds 1.0E -9 Pa·m 3 And/s, indicating that the corresponding inner pipeline has a leak hole. It should be noted that when helium is filled, the pressure of the inner pipe is kept lower than a gauge pressure, and the concentration of helium in the inner pipe is 10%～30％。
And S5, carrying out vacuum negative pressure leak detection on each transition section corresponding to the internal pipeline with the leak hole, and determining the transition section with the leak hole. Specifically, another helium mass spectrometer leak detector 4 with the same specification is sequentially connected to other vacuum safety plugs on the external pipeline, after each connection, when the background leak rate of the helium mass spectrometer leak detector 4 is stable, helium is filled into the internal pipeline with the leak hole by using a helium storage tank 626, and the transition section where the leak hole is located is determined according to the leak rate values of the two helium mass spectrometer leak detectors 4.
It should be noted that, before vacuum negative pressure leak detection is performed on the internal pipe and the transition section, the helium mass spectrometer leak detector needs to be calibrated.
And S6, starting a nitrogen storage tank 615, filling nitrogen into the vacuum interlayer of the vacuum heat insulation pipeline 3, and removing the shell of the transition section where the leak hole is located.
And S7, surrounding all or part of the transition section of the internal pipeline where the leak hole is located by using a helium cover, and determining a real leak point by using a suction gun mode of the helium mass spectrometer leak detector 4. Specifically, a suction gun is inserted into a helium cover, helium is filled into an internal pipeline, a stable leak rate value of the helium mass spectrometer leak detector 4 is observed after a certain time, and the whole leak rate range of the transition section is preliminarily judged; and taking off the helium cover, sequentially detecting the leakage of the suspicious part of the transition section by using a suction gun, and when the leakage rate of a certain position is approximately the same as the whole leakage rate range of the transition section, determining the position as a real leakage point. It should be noted that, the principle of from top to bottom, from far to near, and slow moving speed is usually adopted in the suction gun leak detection, and when the suction gun moves to a real leak point, the signal of the helium mass spectrometer leak detector 4 is obviously enhanced. In order to shorten the leakage detection time, the suction gun is a shorter suction gun hose, such as a metal hose or a plastic hose.
After the actual leakage point is found, the leak hole can be repaired. After the repair is finished, the internal pipeline is filled with helium with high concentration and high pressure (the helium concentration is more than or equal to 50 percent, and the pressure is more than or equal to 2 bar) for leak detection. And (3) firstly, a suction gun leakage detection method is adopted for detection, and when suspicious leakage points cannot be detected by the suction gun leakage detection method, the transition section is subjected to leakage detection alone by combining the vacuum negative pressure leakage detection method. After the leak detection is finished, helium gas filled in all the internal pipelines is recovered to the recovery gas bag 624, and the vacuum interlayer of the vacuum heat insulation pipeline 3 is vacuumized.
Through the steps, the method for detecting the inner pipe leak hole of the vacuum heat insulation pipeline of the test station comprises the steps of firstly connecting all required devices, then evacuating by using an auxiliary evacuation system to enable a vacuum interlayer of the tested heat insulation vacuum pipeline to reach a required vacuum environment, sequentially filling helium gas into the inner pipe of the heat insulation multilayer pipeline after connecting the helium mass spectrometer leak detector, and determining the inner pipeline where the leak hole is located through the output of the helium mass spectrometer leak detector. The invention has the advantages of clarity, clearness, convenience, practicability, simple required equipment and high leak detection efficiency.
The method for detecting the inner pipe leakage hole of the vacuum insulation pipeline of the test station according to the present invention is further explained by a specific example in conjunction with fig. 2 and 3. In fig. 3, a to h represent the numbers of the vacuum relief plugs, and a 'to I' represent the numbers of the respective transition sections.
Step S1, in the detection system of the inner pipe leakage hole of the vacuum heat insulation pipeline of the test station, after the vacuum heat insulation pipeline is used for a long time, five inner pipes A, B, C, D and E are filled with helium at a normal temperature region, and then the vacuum heat insulation pipeline is connected with a helium mass spectrometer leak detector for negative pressure leak detection, wherein the detected leakage rate value is 7.9E -6 Pa·m 3 The vacuum value was 1.01 Pa/s.
In step S2, the second vacuum pump group 622 of the second vacuum unit 62 is activated to evacuate the internal pipes of the vacuum insulation line 3 from a, B, C, D, E to 1.01Pa.
And S3, closing the second vacuum pump unit 622, starting the first vacuum pump unit 613 and the nitrogen storage tank 615 of the first vacuum unit 61, performing nitrogen replacement on the vacuum interlayer of the vacuum heat insulation pipeline 3 for 3-4 times, evacuating to below 5Pa each time, cleaning residual helium impurities in the interlayer, and evacuating to 1.01Pa of the vacuum interlayer before the last replacement.
S4, closing the first vacuum pump group 613 and the nitrogen storage tank 615, connecting and operating the helium mass spectrometer leak detector 4 at the vacuum safety plug a of the vacuum heat insulation pipeline 3, and enabling the background leak rate of the helium mass spectrometer leak detector 4 to be stable and displaying that the local leak rate is less than or equal to 1.0E -13 Pa·m 3 S, use ofHelium storage tank 626 sequentially fills inner pipelines A, B, C, D and F with mixed helium. During inflation, the concentration of helium in the internal pipeline is 10% -30%, and the pressure is 1000Pa. According to the output response of the helium mass spectrometer leak detector 4, the leakage rate change is fast when the tube B is introduced with the mixed helium gas, and the maximum leakage rate is increased to 2.9E -5 Pa·m 3 The/s @1.01Pa, thereby determining that the leakage hole is on the B pipe.
And S5, after the leakage hole of the tube B is determined, connecting the helium mass spectrometer leak detector 4 with the same specification at the rest of safety plugs in sequence through DN25 corrugated pipelines with the length of 500 mm. When the background leak rate of helium mass spectrometer leak detector 4 is stable, helium storage tank 626 is used to pressurize the B tube at a pressure below a gauge pressure. The output response of the helium mass spectrometer leak detector 4 is used for determining which transition section has a leak hole. The specific leak detection sequence is as follows:
1) Arranging helium mass spectrometer leak detectors at a point a of the vacuum plug and a point h of the vacuum plug, and detecting helium leakage before the point a is found at the point h;
2) Transferring the helium mass spectrometer leak detector from the point a to the point b, and detecting helium leakage before the point b by finding the point h;
3) Transferring the helium mass spectrometer leak detector from the point b to a point c, and detecting helium leakage from the point h to the point c;
4) Transferring the helium mass spectrometer leak detector from the point c to the point d, and detecting helium leakage from the point h before the point d;
5) And transferring the helium mass spectrometer leak detector from the point d to the point g, finding that helium leakage is detected at the point g and the point d basically and simultaneously, and determining that the leak hole is in the transition section I' if the leak rate value h is approximately equal to g, d, c, b and a.
And S6, starting a nitrogen storage tank 615, filling nitrogen into the vacuum interlayer of the vacuum heat insulation pipeline 3, and removing the shell of the transition section I'.
And S7, adjusting the helium mass spectrometer leak detector to a suction gun mode, wrapping the suspicious part of the transition section of the inner pipe pipeline or the whole transition section part by using a helium cover, and inserting a suction gun connected with the helium mass spectrometer leak detector into the helium cover. Filling helium gas of 2bar into the tube B, waiting for a certain reaction time, and observing a stable leakage rate value read by the helium mass spectrometer leak detector; then taking off heliumAnd (4) sequentially detecting the leakage of the suspicious part of the transition section I by using a suction gun. When the signal of the helium mass spectrometer leak detector is obviously enhanced, the maximum leak rate of the suction gun is 5.0 multiplied by 10 -6 Pa·m 3 And/s, accurately finding out the real leak point with the length of 1-2 mm.
And after the actual leakage point is found, repairing or replacing the leakage hole. And after repairing, filling helium with high concentration and high pressure (the helium concentration is more than or equal to 50 percent, and the pressure is more than or equal to 2 bar) into the tube B for leak detection. And (3) firstly, a suction gun leakage detection method is adopted for detection, and when suspicious leakage points cannot be detected by the suction gun leakage detection method, the transition section is subjected to leakage detection alone by combining a vacuum negative pressure leakage detection method. After the leak detection is finished, helium gas filled in all the internal pipelines is recovered to the recovery gas bag 624, and the vacuum interlayer of the vacuum heat insulation pipeline 3 is vacuumized.
The invention realizes the detection of the inner pipes of the vacuum heat insulation pipeline one by one and in sections, can accurately and quickly determine the inner pipe with the leak hole, quickly and accurately position the range of the leak hole, and improves the detection efficiency and the detection accuracy. The position of the transition section where the leak hole is located can be roughly determined by the negative pressure helium mass spectrometer leak detection method, the method has the advantages of high sensitivity and low cost, the specific position of the leak hole can be well detected by combining the positive pressure suction gun leak detection method, and the operation is simple, convenient and quick. In the leak detection process, the leak detector and the auxiliary nitrogen and helium sources are controlled simultaneously, the leak rate change, the data analysis, the feedback operation and the like are observed in time, and a plurality of operators work in a cooperative manner. Through the practical application of the vacuum heat insulation pipeline of the test station, the invention can accurately and effectively determine the position range and the leakage rate of the leakage point.
The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.
Claims (10)
1. A detection system for a leak hole in an inner pipe of a vacuum heat insulation pipeline of a test station is characterized by comprising a vacuum heat insulation pipeline for transmitting low-temperature liquid generated by a low-temperature refrigerator to a distribution valve box, wherein the vacuum heat insulation pipeline is connected with at least one helium mass spectrometer leak detector; the vacuum heat insulation pipeline is formed by welding a plurality of prefabricated sections through corresponding transition sections, each prefabricated section comprises an inner pipeline, an outer pipeline and a vacuum interlayer between the inner pipeline and the outer pipeline, a vacuum safety plug is arranged on the outer pipeline of each prefabricated section, and at least one prefabricated section is connected with an auxiliary evacuation system.
2. The system of claim 1, wherein the vacuum safety plug has a matching safety plug fixture, and the helium mass spectrometer leak detector is sealingly connected to the safety plug fixture by a bellows.
3. The test station vacuum insulated line inline leak detection system of claim 1, wherein the diameter of the bellows is the same as the diameter of the exhaust port of the helium mass spectrometer leak detector.
4. The test station vacuum insulated pipeline leak detection system of claim 1, wherein the bellows is in the form of a stainless steel bellows KF interface.
5. A test station vacuum insulated line duct leak detection system according to claim 1, characterized in that the auxiliary evacuation system comprises a first vacuum unit acting on the vacuum interlayer and a second vacuum unit acting on the inner duct.
6. The system for detecting the inner pipe leakage hole of the test station vacuum insulation pipeline as claimed in claim 5, wherein the first vacuum unit comprises a vacuum valve and a first vacuum pump set which are sequentially connected with the vacuum interlayer through a first pumping branch, a vacuum gauge is connected to a section of the first pumping branch between the vacuum interlayer and the vacuum valve, and a nitrogen storage tank is connected to a section of the first pumping branch between the vacuum valve and the first vacuum pump set.
7. The system for detecting the leak hole in the pipe inside the vacuum insulation pipeline of the test station as claimed in claim 6, wherein the vacuum gauge is connected to the first pumping branch through an angle valve, the nitrogen storage tank is connected to the first pumping branch through a nitrogen supply branch, and a pressure gauge and a block valve are arranged on the nitrogen supply branch.
8. The system of claim 5, wherein the second vacuum unit comprises a plurality of inner tube branches respectively connected to the inner tubes, the inner tube branches being connected to the second vacuum pump set through a second air suction branch, to the recovery air bag through a helium recovery branch, and to the helium storage tank through a helium supply branch.
9. The system of claim 8, wherein the second pumping branch comprises a pump switching valve, the helium recovery branch comprises an air bag on-off valve, the helium supply branch comprises a storage tank on-off valve, and the inner tube branch comprises an inner tube process valve.
10. A method for detecting inner pipe leakage holes of a vacuum heat insulation pipeline of a test station is characterized by comprising the following steps:
step S1, providing a detection system for a leak hole of an inner pipe of a vacuum insulated pipeline of a test station according to claims 1-9;
s2, starting a second vacuum pump set of a second vacuum unit, and evacuating the inner pipeline of the vacuum heat insulation pipeline to below 5 Pa;
s3, closing the second vacuum pump set, starting the first vacuum pump set and the nitrogen storage tank of the first vacuum unit, performing nitrogen replacement on the vacuum interlayer of the vacuum heat insulation pipeline for a plurality of times, evacuating to below 5Pa each time, and cleaning helium impurities remained in the vacuum interlayer;
s4, closing the first vacuum pump group and the nitrogen storage tank, communicating the vacuum heat insulation pipeline with a helium mass spectrometer leak detector, performing vacuum negative pressure leak detection on an inner pipeline of the vacuum heat insulation pipeline, and determining the inner pipeline with a leak hole;
s5, performing vacuum negative pressure leak detection on each transition section corresponding to the internal pipeline with the leak hole, and determining the transition section of the internal pipeline with the leak hole;
s6, starting the nitrogen storage tank, filling nitrogen into a vacuum interlayer of the vacuum heat insulation pipeline, and removing a shell of a transition section where the leakage hole is located;
and S7, starting a helium storage tank, filling helium into the inner pipeline with the leak holes of the vacuum insulation pipeline, surrounding all or part of the transition section of the inner pipeline with the leak holes by adopting a helium cover, and determining a real leak point by utilizing a suction gun mode of the helium mass spectrometer leak detector.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210971343.7A CN115371902A (en) | 2022-08-12 | 2022-08-12 | Detection system and method for inner pipe leakage hole of vacuum heat insulation pipeline of test station |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210971343.7A CN115371902A (en) | 2022-08-12 | 2022-08-12 | Detection system and method for inner pipe leakage hole of vacuum heat insulation pipeline of test station |
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| CN115371902A true CN115371902A (en) | 2022-11-22 |
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| CN202210971343.7A Pending CN115371902A (en) | 2022-08-12 | 2022-08-12 | Detection system and method for inner pipe leakage hole of vacuum heat insulation pipeline of test station |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117168713A (en) * | 2023-11-03 | 2023-12-05 | 安徽诺益科技有限公司 | Helium-hydrogen mass spectrometer leak detector signal rapid processing system and method |
| CN117506105A (en) * | 2023-11-27 | 2024-02-06 | 盐城芯丰微电子有限公司 | Preventive maintenance device for gold-palladium-copper eutectic welding upper control console |
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2022
- 2022-08-12 CN CN202210971343.7A patent/CN115371902A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117168713A (en) * | 2023-11-03 | 2023-12-05 | 安徽诺益科技有限公司 | Helium-hydrogen mass spectrometer leak detector signal rapid processing system and method |
| CN117168713B (en) * | 2023-11-03 | 2024-02-13 | 安徽诺益科技有限公司 | Helium-hydrogen mass spectrometer leak detector signal rapid processing system and method |
| CN117506105A (en) * | 2023-11-27 | 2024-02-06 | 盐城芯丰微电子有限公司 | Preventive maintenance device for gold-palladium-copper eutectic welding upper control console |
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