Leakage rate detection device and method for bolted flange connection system under multiple working conditions

Abstract

The application discloses a kind of simulation under multi-working condition bolt flange connection system leakage rate detection device and method.The device includes medium supply system, medium sealing system, leakage rate detection system, load applying system, heating temperature regulating system and data acquisition analysis system.The application adopts vacuum heat insulation sealing structure, forms the set leakage cavity with good sealing performance.Load applying system adopts electro-hydraulic servo actuator and load loading arm, and vibration and bending moment are applied to bolt flange connection system.The application can simulate multiple actual working conditions, measures the leakage rate of bolt flange connection system under temperature fluctuation, medium pressure fluctuation, bending moment and mechanical vibration and other conditions by collecting leakage medium, and the measurement precision is higher than that of common pressure drop method.The device is used to measure the leakage rate of bolt flange connection system, and monitor and evaluate the stress condition of bolt and sealing performance, so as to predict the service life, and ensure the safety of bolt flange connection system.

Description

TECHNICAL FIELD

[0001] The application provides a device and a method for detecting the leakage rate of a bolted flange connection system under multiple working conditions, which are suitable for detecting the leakage rate of the bolted flange connection system under the conditions of temperature fluctuation, medium pressure fluctuation, and external bending moment and mechanical vibration, and can be used for evaluating the sealing performance of the bolted flange connection system and predicting the service life thereof. BACKGROUND

[0002] The bolted flange connection is a commonly used connection mode in equipment and pipelines, and is widely used in petrochemical, chemical, nuclear power, metallurgy, pharmaceutical and other industries due to the advantages of easy disassembly and installation. In production and construction, the temperature and medium pressure fluctuate due to the influence of external environment, and therefore the flange may change in deflection, warping, creep, crack propagation and the like, and the stress of each part of the flange changes complexly. When there is an external bending moment or vibration, the stress characteristics of each part of the flange will also change greatly, and the deflection, warping and crack may aggravate the leakage. The flange device may also have phenomena such as bolt loosening, fatigue and stress relaxation, which may bring safety hazards to the normal operation of the equipment. According to statistics, the leakage of the bolted flange connection system is one of the main reasons for major accidents in petrochemical and other enterprises. Therefore, the influence of temperature and medium pressure fluctuation and the application of external bending moment and mechanical vibration on the tightness of the bolted flange connection system is an urgent problem to be solved in engineering practice at present.

[0003] From the development status at home and abroad, the research on the sealing performance of the bolted flange connection system under the action of external bending moment and vibration environment only stays in the mechanical analysis of the failure of the bolted flange under static load, and the sealing performance of the flange is improved by changing the machining process and material performance of the flange and gasket. At present, the theoretical analysis of the failure and leakage of the bolted flange connection system under the action of external bending moment and vibration load is not mature. Although some people abroad have carried out experiments on the loosening of a single bolt under vibration, there is no relevant patent to analyze the failure of the bolted flange connection system under vibration in detail, so the time standard for the failure of the bolted flange connection system under the action of external bending moment and vibration cannot be given.

[0004] At present, there is no corresponding standard for the measurement method of the leakage rate of the bolted flange connection system under the action of temperature and medium pressure fluctuation, and external bending moment and mechanical vibration. In actual production, the occurrence time of the leakage of the bolted flange connection system caused by external load and the size of the leakage rate are not clear. In view of the above actual problems, the existing detection device is improved. SUMMARY

[0005] The present application aims at the problem that the load of the bolt flange connection system is complex under actual working conditions and the leakage rate is difficult to measure, and provides a device for measuring the leakage rate of the bolt flange connection system under multiple working conditions.

[0006] Based on the above detection device, the present application further provides a method for measuring the leakage rate of the bolt flange connection system under multiple working conditions.

[0007] The specific technical scheme adopted by the present application is as follows:

[0008] A device for measuring the leakage rate of the bolt flange connection system under multiple working conditions, comprising a medium supply system, a medium sealing system, a leakage rate detection system, a load application system, a heating and temperature adjusting system and a data acquisition and analysis system.

[0009] The medium sealing system comprises a bolt flange connection system, a sealing outer cover and a sealing inner cover, the sealing outer cover covers the sealing inner cover, and a sealing test cavity is formed between the two covers; the sealing outer cover is provided with an upper pipeline and a lower pipeline, which are connected through the bolt flange connection system, and a test gasket is arranged at the flange matching position.

[0010] The leakage rate detection system comprises a leakage collection cover, a leakage collection sealing assembly, a gas leakage detection pipeline and a leakage detection device, the leakage collection cover covers the outside of the bolt flange connection system, the upper end of the leakage collection cover is connected to the upper pipeline of the sealing outer cover through the leakage collection sealing assembly, the lower end of the leakage collection cover is sealingly connected to the leakage collection cover rack through the leakage collection cover bolt, and the leakage collection cover rack is welded to the outside of the lower pipeline of the sealing outer cover.

[0011] The load application system is used for applying mechanical vibration and external bending moment to the bolt flange connection system, and comprises an electro-hydraulic servo actuator and two load loading arms, the two load loading arms are connected to the upper pipeline and the lower pipeline of the sealing outer cover respectively, and the bottom of the pipeline lower head of the lower pipeline is further provided with a universal wheel for rolling support.

[0012] Further, the leakage collection sealing assembly of the leakage rate detection system comprises a vacuum heat insulation sleeve, an insulation sleeve, an O-shaped sealing ring and an O-ring pressing sleeve, the vacuum heat insulation sleeve is welded to the outside of the upper pipeline of the sealing outer cover, a vacuum heat insulation cavity is arranged in the vacuum heat insulation sleeve, an insulation sleeve is arranged on the outside of the vacuum heat insulation sleeve, O-shaped ring pressing grooves are arranged on the mating surfaces of the insulation sleeve and the O-ring pressing sleeve respectively, the O-shaped sealing ring is installed between the insulation sleeve and the O-ring pressing sleeve through the O-shaped ring pressing grooves, and the outside of the O-ring pressing sleeve is welded to the leakage collection cover as a whole.

[0013] Further, the medium supply system is used for conveying gaseous medium to the medium sealing system and realizing the rise and fall of medium pressure; comprising a gas cylinder, a pressure reducing valve, a pressure stabilizing tank, an intelligent electric control valve and an air inlet pipeline which are sequentially communicated; the air inlet pipeline is welded on the lower pipeline and located between the load loading arm and the fixed support.

[0014] Further, the heating and temperature regulating system comprises a temperature controller and a resistance wire heater arranged in the sealed inner cover body; the resistance wire heater is inserted into the sealed inner cover body from top to bottom and installed at the top end of the upper pipeline; the heating and temperature regulating system heats the gaseous medium through the resistance wire heater and adjusts the temperature of the gaseous medium of the medium sealing system through the temperature controller so as to simulate the fluctuation of the medium temperature of the bolt flange connection system under real working conditions.

[0015] Further, the data acquisition and analysis system comprises a first temperature sensor arranged outside the test gasket, a second temperature sensor arranged at the inlet of the heat exchanger, a third temperature sensor arranged at the outlet of the heat exchanger and strain gauges arranged on the bolt flange connection system.

[0016] Further, the strain gauges are eight in total and are welded on the eight flange bolts of the bolt flange connection system respectively and are used for measuring the bolt stress of each flange bolt under loading.

[0017] A method for simulating the leakage rate of a bolt flange connection system under multiple working conditions, based on the above-mentioned device for simulating the leakage rate of a bolt flange connection system under multiple working conditions, is used for simulating the running state of the bolt flange connection system under multiple working conditions such as temperature fluctuation, medium pressure fluctuation, outer bending moment change and different frequency mechanical vibration and measuring the leakage rate, comprising the following steps:

[0018] Step 1), installation of the measuring device:

[0019] 1.1) installing a ball universal shaft at the bottom of the lower head of the lower pipeline and then installing universal wheels;

[0020] 1.2) installing a test gasket on the lower flange of the bolt flange connection system;

[0021] 1.3) installing an upper flange on the lower flange;

[0022] 1.4) installing strain gauges and a first temperature sensor; the connecting wires of the strain gauges and the first temperature sensor are led out through the wire outlet hole A at the bottom of the collection cover stand;

[0023] 1.5) installing a collection cover gasket on the collection cover stand;

[0024] 1.6) Install the collecting leakage cover, place the O-shaped sealing ring in the O-shaped sealing ring pressing groove, press it through the heat insulation sleeve and the O-shaped ring pressing sleeve, and seal the leakage of the wire outlet hole A at the bottom of the collecting leakage cover rack with sealant, so as to ensure good sealing performance of the collecting leakage cover;

[0025] 1.7) The fixing support includes upper and lower fixing supports. The left sides of the upper and lower fixing supports are fixed with the steel frame. Then the device installed above is moved into the clasp of the fixing support, and the clasp is fixed to ensure good stability of the device and prepare for subsequent application of bending moment and mechanical vibration;

[0026] 1.8) Install the electro-hydraulic servo actuator on the steel frame;

[0027] 1.9) Fix the clasp of the load loading arm on the upper and lower pipes, and install the load loading arm on the electro-hydraulic servo actuator;

[0028] 1.10) Insert the resistance wire heater into the sealed inner cover body from top to bottom, and install it at the top end of the upper pipe, with the wire leading out from the top;

[0029] 1.11) Connect the connecting wires of the strain gauges and temperature sensors to the data collector, connect the liquid crystal control panel to the electro-hydraulic servo actuator, and connect the wires of the resistance wire heater to the temperature controller;

[0030] 1.12) Connect the medium supply system to the inlet pipe;

[0031] 1.13) Connect the leakage rate detection system to the gas leak detection pipe;

[0032] Step 2), gas medium supply:

[0033] 2.1) Open the gas cylinder valve to make the gas medium flow into the pipe;

[0034] 2.2) Open the pressure reducing valve to reduce the pressure of the gas medium, make the gas medium flow into the pressure stabilizing tank, and stabilize the pressure of the gas medium;

[0035] Step 3), test condition adjustment:

[0036] 3.1) Turn on the electro-hydraulic servo actuator and the liquid crystal control panel. The electro-hydraulic servo actuator applies a predetermined size of external force to the bolt flange connection system through the load loading arm, as well as a vibration with a predetermined frequency and amplitude;

[0037] 3.2) Calibrate the volume of the sealing leakage cavity to obtain the volume V1 of the sealing leakage cavity, the volume V2 of the pipe between the gas leak detection pipe and the inlet side of the heat exchanger, and the volume V3 of the pipe between the outlet side of the heat exchanger and the three-way valve;

[0038] 3.3) Turn on the data acquisition and analysis system to ensure that each sensor is working properly;

[0039] 3.4) Turn on the resistance wire heater, and adjust the resistance wire heater through the temperature controller to heat the sealed test chamber;

[0040] 3.5) Adjust the medium supply system, and adjust the intelligent electric control valve to make the pressure in the medium sealing system reach the preset pressure, and achieve the fluctuation of the pressure in the medium sealing system;

[0041] Step 4), leakage medium measurement:

[0042] 4.1) Collect the temperature data of each temperature sensor in the analysis system, and the bolt load data measured by the strain gauges on each flange bolt;

[0043] 4.2) According to the leakage rate, select one of the three leakage measurement methods of helium mass spectrometry, U-tube leak detection method and cavity pressurization method for measurement;

[0044] Step 5), end the experiment:

[0045] 5.1) After the experiment is completed, first close the medium supply system, and then exhaust the high-pressure gas in the sealing system;

[0046] 5.2) Turn off the power supply and cool down the device;

[0047] 5.3) Remove the heating and temperature control system, load application system and medium sealing system to replace the test gasket for the next test.

[0048] Further, the helium mass spectrometry method includes the following steps:

[0049] 1) Open the exhaust passage of the three-way valve to exhaust the leakage gas medium from the three-way valve exhaust passage to the outside;

[0050] 2) Open the second exhaust valve and close the first exhaust valve and the third exhaust valve;

[0051] 3) Open the three-way valve to connect the front and rear gas leak detection pipelines, and the gas medium is sucked into the helium mass spectrometer through the gas leak detection pipeline by the suction nozzle of the helium mass spectrometer;

[0052] 4) Observe the change of the helium mass spectrometer leak rate reading and record the leakage rate.

[0053] Further, the cavity pressurization method includes the following steps:

[0054] 1) Open the exhaust passage of the three-way valve to exhaust the leakage gas medium from the three-way valve exhaust passage to the outside;

[0055] 2) opening the third exhaust valve, closing the first exhaust valve and the second exhaust valve;

[0056] 3) opening the three-way valve to make the front and rear gas leak detection pipe communicate, and starting timing, and using the micro pressure sensor to measure the pressure of the medium at the outlet of the gas leak detection pipe;

[0057] 4) the first temperature sensor measures the temperature T1 of the test gasket;

[0058] 5) the second temperature sensor measures the gas medium temperature T2 at the inlet of the heat exchanger;

[0059] 6) the third temperature sensor measures the gas medium temperature T3 at the outlet of the heat exchanger;

[0060] 7) collecting data through the data collector in the data acquisition analysis system, and recording the test data;

[0061] 8) substituting the volumes V1, V2 and V3 and the temperatures T1, T2 and T3 into the ideal gas state equation, first obtaining the total number of moles of gas in the sealed leak-free cavity according to the ideal gas state equation, and then converting the number of moles of leaked medium into the volume under standard conditions, so as to measure the size of the gas volume leakage rate per unit time.

[0062] Further, the U-shaped tube leak detection method comprises the following steps:

[0063] 1) opening the exhaust passage of the three-way valve, so that the leaked gas medium is discharged from the exhaust passage of the three-way valve to the outside;

[0064] 2) opening the first exhaust valve, closing the second exhaust valve and the third exhaust valve;

[0065] 3) opening the three-way valve to make the front and rear gas leak detection pipe communicate, and starting timing, and observing the height difference of the U-shaped tube on both sides;

[0066] 4) calculating the size of the leakage rate by observing the change of the liquid height difference of the U-shaped tube on both sides.

[0067] Compared with the prior art, the present application has the following beneficial effects:

[0068] 1) The present application can simulate various actual working conditions, and measures the leakage rate of the bolt flange connection system under the conditions of temperature fluctuation, medium pressure fluctuation, bending moment and mechanical vibration by collecting the leaked medium, so as to study the influence of different working conditions on the leakage rate of the bolt flange connection system, and the present application has a wider application range than the conventional measurement method and is closer to the actual situation.

[0069] 2、The leakage rate detection device of the present application is used for measuring the leakage rate of the bolt flange connection system, monitoring the stress of the bolt and evaluating the sealing performance, so as to predict the service life and ensure the safety of the bolt flange connection system.

[0070] 3、The present application adopts the vacuum heat insulation sealing structure to form the leakage collection cavity with good sealing performance. The leakage rate detection system adopts the leakage collection sealing assembly to effectively seal the leakage collection cover and the sealing outer cover body. The leakage collection sealing assembly sequentially adopts the vacuum heat insulation sleeve, the heat insulation sleeve, the O-shaped sealing ring and the O-shaped ring pressing sleeve. The vacuum heat insulation sleeve is heat insulated, the heat insulation sleeve is further heat insulated and insulated, and the O-shaped sealing ring plays a sealing role. The heat insulation sleeve and the O-shaped ring pressing sleeve are both provided with the O-shaped ring pressing groove, the O-shaped sealing ring is arranged in the pressing groove, and the sealing effect is enhanced. The vacuum heat insulation sleeve is welded on the upper pipeline, the inside is a vacuum environment, and the heat insulation effect is achieved. The outer layer of the heat insulation sleeve is composed of the heat insulation material, and the purpose is to prevent metal heat conduction and further play a heat insulation role, prevent the high temperature working condition from affecting the sealing performance of the O-shaped sealing ring, and improve the measurement accuracy.

[0071] 4、The design of the load applying system of the present application can apply vibration and bending moment to the bolt flange connection system respectively, or simultaneously apply vibration and bending moment. Compared with the existing device which only applies bending moment and measures the leakage rate by the pressure drop method, the measurement accuracy is higher. The pressure drop method has low measurement accuracy due to the influence of leakage at other positions. The present application designs the leakage collection sealing assembly for sealing and measures the leakage rate by collecting the leakage medium, and the measurement accuracy is higher.

[0072] 5、The leakage collection cover in the device not only plays a role in collecting the leakage medium, but also can prevent the explosion of the test gasket from causing harm to the instrument and personnel, and has high safety. BRIEF DESCRIPTION OF DRAWINGS

[0073] The present application will be further described below in combination with the drawings and examples:

[0074] Figure 1 It is a structural schematic diagram of the device of the present application;

[0075] Figure 2 It is Figure 1 It is an enlarged view of B in the middle;

[0076] Figure 3 It is a structural schematic diagram of the leakage detection device in the present application;

[0077] In the figure: 1. upper pipe, 2. vacuum insulation sleeve, 3. insulation sleeve, 4. O-ring compression sleeve, 5. upper flange, 6. lower flange, 7. flange bolt, 8. leak collection cover bolt, 9. leak collection cover gasket, 10. leak collection cover stand, 11. gas leak detection pipe, 12. leak detection device, 13. gas cylinder, 14. pressure reducing valve, 15. pressure stabilizing tank, 16. intelligent electric control valve, 17. gas inlet pipe, 18. pipe lower head, 19. ball universal shaft, 20. universal wheel, 21. resistance wire heater, 22. lower pipe, 23. test gasket, 24. first temperature sensor, 25. strain gauge, 26. data acquisition device, 27. lower fixing support, 28. computer, 29. steel frame, 30. electro-hydraulic servo actuator, 31. liquid crystal control panel, 32. leak collection cover, 33. O-ring, 34. load loading arm, 35. sealed inner cover body, 36. upper fixing support, 37. temperature controller, 38. second temperature sensor, 39. heat exchanger, 40. third temperature sensor, 41. three-way valve, 42. first exhaust valve, 43. U-shaped tube, 44. micro pressure sensor, 45. second exhaust valve, 46. helium mass spectrometer leak detector, 47. third exhaust valve. DETAILED DESCRIPTION

[0078] The present application will be further described below in conjunction with the accompanying drawings:

[0079] Example 1:

[0080] In Figure 1 the present application, the simulated multi-condition bolt flange connection system leak rate detection device includes six systems, which are: medium supply system, medium sealing system, leak rate detection system, load application system, heating and temperature control system and data acquisition and analysis system.

[0081] The medium supply system is used to transport gas medium to the medium sealing system. The intelligent electric control valve 16 in the system can adjust the delivery pressure of the gas medium in a short time to realize the rise and fall of the pressure, simulating the pressure fluctuation of the medium.

[0082] The medium sealing system is used to seal the test medium; it includes a bolt flange connection system, a sealing outer cover body and a sealing inner cover body 35. The sealing outer cover body is covered outside the sealing inner cover body 35, and a sealed test cavity is formed between the two cover bodies. The sealing outer cover body is provided with an upper pipe 1 and a lower pipe 22, which are connected through the bolt flange connection system and provided with a test gasket 23 at the flange matching position.

[0083] A leak rate detection system for measuring the leakage rate of a medium leaking from a sealed test chamber; comprising a leak collection cover 32, a leak collection seal assembly, a gas leak detection pipeline 11, and a leak detection device 12. The leak collection cover 32 is covered on the outside of the bolt flange connection system. The upper end of the leak collection cover 32 is connected to the upper pipeline 1 of the sealed outer cover body through the leak collection seal assembly. The lower end of the leak collection cover 32 is sealedly connected to the leak collection cover stand 10 via leak collection cover bolts 8. The leak collection cover stand 10 is welded to the outside of the lower pipeline 22 of the sealed outer cover body.

[0084] like Figure 2 As shown, the leakage collection and sealing assembly of the leakage rate detection system includes a vacuum insulation sleeve 2, an insulating sleeve 3, an O-ring 33 and an O-ring compression sleeve 4. The vacuum insulation sleeve 2 is welded to the outside of the upper pipe 1 of the sealed outer cover. A vacuum insulation cavity is provided in the vacuum insulation sleeve 2, and an insulating sleeve 3 is provided on the outside thereof. The mating surfaces of the insulating sleeve 3 and the O-ring compression sleeve 4 are respectively provided with O-ring compression grooves. The O-ring 33 is installed between the insulating sleeve 3 and the O-ring compression sleeve 4 through the O-ring compression groove. The outer side of the O-ring compression sleeve 4 is welded to the leakage collection cover 32 as a whole.

[0085] The load application system, used to apply mechanical vibration and external bending moment to the bolted flange connection system, includes an electro-hydraulic servo actuator 30 and two load-applying arms 34. The electro-hydraulic servo actuator 30 is fixedly supported by a steel frame 29. The sealing outer cover of the media sealing system is also mounted on the steel frame 29 via a fixed bracket. The two load-applying arms 34 are respectively connected to the upper pipe 1 and lower pipe 22 of the sealing outer cover. The bottom of the lower pipe head 18 of the lower pipe 22 is also equipped with a universal wheel 20 for rolling support.

[0086] The heating and temperature control system is used to adjust and control the temperature of the medium sealing system and simulate temperature fluctuations. It includes a temperature controller 37 and a resistance wire heater 21 arranged in the sealed inner cover 35. The resistance wire heater 21 is inserted into the sealed inner cover 35 from top to bottom and is placed on the top of the upper pipe 1 through the flange structure of the resistance wire heater 21. The heating and temperature control system heats the gas medium through the resistance wire heater 21 and adjusts the gas medium temperature of the medium sealing system through the temperature controller 37 to simulate the fluctuation of the medium temperature of the bolt flange connection system under real working conditions.

[0087] The data acquisition and analysis system is used to acquire and process the detection data of each sensor, and obtain the bolt stress of the bolt flange connection system, the temperature data of the sealing test cavity, and the temperature and pressure changes at the gas leak detection pipeline. The data acquisition and analysis system comprises a first temperature sensor 24 arranged outside the test gasket 23, a second temperature sensor 38 arranged at the inlet of the heat exchanger 39, a third temperature sensor 40 arranged at the outlet of the heat exchanger 39, and a strain gauge 25 arranged at the bolt flange connection system. The data acquisition and analysis system can further comprise a data collector 26, a computer 28, and a liquid crystal control panel 31 connected to the electro-hydraulic servo actuator 30. The strain gauge 25 has a total of 8, and is welded on the 8 flange bolts 7 of the bolt flange connection system, respectively, for measuring the bolt stress of each flange bolt 7 during loading; the data collector 26 is connected with the temperature sensor, the strain gauge 25, the micro pressure sensor 44 and the computer 28, respectively, for measuring the temperature and pressure changes of the medium, and providing temperature data for calculating the leakage rate of the leak collection cavity.

[0088] Embodiment two:

[0089] The leakage rate detection device in the example comprises a medium supply system, a medium sealing system, a leakage rate detection system, a load applying system, a heating and temperature adjusting system, and a data acquisition and analysis system, and the specific structure is shown in Figure 1 .

[0090] The medium supply system is used to transport the gas medium to the medium sealing system, and to realize the increase and decrease of the medium pressure; and comprises a gas cylinder 13, a pressure reducing valve 14, a pressure stabilizing tank 15, an intelligent electric control valve 16 and an air inlet pipeline 17 which are sequentially communicated. The air inlet pipeline 17 is welded on the lower pipeline 22 and located between the load loading arm 34 and the fixed support. The test gas medium can adopt helium, which is safe and convenient for testing. The gas medium is transported from the gas cylinder 13 to the pressure stabilizing tank 15 through the pressure reducing valve 14, and then passes through the intelligent electric control valve 16. The intelligent electric control valve 16 adopts a ball valve, which can adjust the delivery pressure of the medium gas in a short time, realize the increase and decrease of the medium pressure, simulate the fluctuation of the gas medium pressure under the actual working condition of the bolt flange connection system, and finally enter the air inlet pipeline 17. The gas medium enters the medium sealing system.

[0091] The medium sealing system comprises a bolt flange connection system, a sealing inner cover 35 and a sealing outer cover. The bolt flange connection system comprises an upper flange 5, a test gasket 23, a lower flange 6 and a flange bolt 7; the upper flange 5 of the bolt flange connection system is welded with the upper pipeline 1, and the lower flange 6 is welded with the lower pipeline 22, and the lower end of the lower pipeline 22 is welded with the pipeline lower head 18, thereby forming the sealing outer cover; the cavity between the inner cover and the outer cover forms the sealing test cavity. In this example, the sealing inner cover 35 is made of metal material for better heat conduction.

[0092] The leakage rate detection system comprises a vacuum insulation sleeve 2, an insulation sleeve 3, an O-shaped sealing ring 33, an O-shaped ring pressing sleeve 4, a leakage collection cover 32, a leakage collection cover rack 10, a leakage collection cover gasket 9, a leakage collection cover bolt 8, a gas leakage detection pipeline 11 and a leakage detection device 12. The leakage collection cover rack 10 is in a circular cross section and is arranged at a position below the welding position of the lower flange 6 and the lower pipeline 22. The leakage collection cover 32 is arranged outside the bolt flange connection system and is fixedly installed on the leakage collection cover rack 10 through the leakage collection cover bolt 8, the leakage collection cover gasket 9 and the leakage collection cover rack 10. The upper end of the leakage collection cover 32 is welded with the O-shaped ring pressing sleeve 4, and the vacuum insulation sleeve 2 is welded at a position above the welding position of the upper flange 5 and the upper pipeline 1. The vacuum insulation sleeve 2 is in a vacuum environment and has a certain heat insulation effect. A layer of insulation sleeve 3 is wrapped outside the vacuum insulation sleeve 2, and the insulation sleeve 3 is composed of heat insulation materials and prevents heat transfer of the metal, thereby further playing a heat insulation effect. The insulation sleeve 3 and the O-shaped ring pressing sleeve 4 are provided with O-shaped sealing ring pressing grooves. The O-shaped sealing ring 33 is arranged in the O-shaped sealing ring pressing groove and is pressed by the insulation sleeve 3 and the O-shaped ring pressing sleeve 4, thereby achieving a sealing effect. The leakage collection cover 32, the vacuum insulation sleeve 2, the insulation sleeve 3, the O-shaped sealing ring 33 and the O-shaped ring pressing sleeve 4 form a leakage collection cavity with the leakage collection cover rack 10. The bottom of the leakage collection cover rack 10 is provided with the gas leakage detection pipeline 11, the gas leakage detection pipeline 11 transports the leaked medium gas to the leakage detection device 12, and the leakage detection device 12 comprises a second temperature sensor 38, a heat exchanger 39, a third temperature sensor 40 and a three-way valve 41 in sequence, and is then divided into three paths. One path is transported to the U-shaped pipe 43 through the first exhaust valve 42; another path is connected with the third exhaust valve 47 and the micro-pressure sensor 44; and the last path is sequentially connected with the second exhaust valve 45 and the helium mass spectrometric leak detector 46. Therefore, one of the three leakage detection modes can be selected according to the leakage rate to measure the leakage rate. The other side of the bottom of the leakage collection cover rack 10 is provided with a wire arranging hole A, and the wires of the strain gauge 25 and the first temperature sensor 24 pass through the wire arranging hole A and are connected with the data collector 26. After the wires are arranged, the wire arranging hole A is sealed with sealing glue to ensure the good sealing performance of the leakage collection cavity.

[0093] The load applying system includes an electro-hydraulic servo actuator 30, a load applying arm 34, an upper fixing support 36, a lower fixing support 27 and a universal wheel 20. The electro-hydraulic servo actuator 30 is fixed on the steel frame 29, and can adjust the external force applied on the upper pipe 1 and the lower pipe 22, the frequency, amplitude and other parameters of the vibration through the liquid crystal control panel 31, and then apply the vibration and bending moment to the bolted flange connection system through the load applying arm 34. There is a load applying arm 34 between the upper fixing support 36 and the upper flange 5 and between the lower fixing support 27 and the lower flange 6. There is a fixing support connected with the steel frame 29 between the load applying arm 34 and the top of the upper and lower pipes, so as to fix the device. The fixing support and the load applying arm 34 interact, so as to apply the required bending moment and vibration of different frequencies and amplitudes. There is a universal wheel 20 at the bottom of the device, which can rotate 360°, and can facilitate the movement of the device and support the measuring device. The load applying system is used to simulate the mechanical vibration and external bending moment of the bolted flange connection system in the actual working condition.

[0094] The heating and temperature adjusting system includes a resistance wire heater 21 and a temperature controller 37 arranged in the sealed inner cover 35. The resistance wire heater 21 is inserted into the sealed inner cover 35 from top to bottom, and is placed on the top of the upper pipe 1 through the flange structure of the resistance wire heater 21, and the lead wire is led out from the top and connected with the temperature controller 37. The heating and temperature adjusting system heats the gas medium through the resistance wire heater 21, and adjusts the temperature of the gas medium of the medium sealing system through the temperature controller 37, so as to simulate the fluctuation of the medium temperature of the bolted flange connection system in the actual working condition.

[0095] The data acquisition and analysis system comprises a first temperature sensor 24 arranged outside the test gasket 23, a second temperature sensor 38 arranged at the inlet of the heat exchanger 39, a third temperature sensor 40 arranged at the outlet of the heat exchanger 39, and a strain gauge 25 arranged on the flange bolt 7, and can further comprise a data collector 26, a computer 28, and a liquid crystal control panel 31. The bolt flange connection system comprises eight sets of bolt flange structures, and the strain gauges 25 are 8 in total and are welded on the flange bolts 7 respectively, for measuring the bolt stress of each flange bolt 7 under loading, ensuring the accuracy of bolt force loading, and further measuring the bolt stress change of the flange bolt 7 under vibration and bending moment. The liquid crystal control panel 31 is connected with the electro-hydraulic servo actuator 30 through wires, for displaying the external force applied on the upper pipeline 1 and the lower pipeline 22, and the frequency, amplitude and other information of the vibration. The data collector 26 is connected with the first temperature sensor 24, the second temperature sensor 38, the third temperature sensor 40, the strain gauges 25, the micro pressure sensor 44 and the computer 28 respectively, for measuring the temperature change and pressure change of the medium, and providing the temperature change and gas medium pressure data for calculating the leakage rate of the leak collection cavity pressurization method. The system takes the computer 28 as the core, various sensors convert various measured parameters into analog voltage signals, the signals are amplified or attenuated through an amplifier, and are converted into digital quantities through an A / D converter, and are connected with the computer 28 through an input interface. The test results can be output in different forms such as data, tables, curves or fitting formulas through peripheral devices.

[0096] Example three

[0097] Further design of the embodiment is that the bolt flange connection system leakage rate measuring device under the action of vibration and bending moment in the example simulates the medium pressure fluctuation of the bolt flange connection system under actual working conditions; the load applying system simulates the bending moment action and mechanical vibration of different sizes received by the bolt flange connection system under actual working conditions; and the heating and temperature adjusting system simulates the temperature fluctuation received by the bolt flange connection system under actual working conditions. Through the measurement of the leakage rate of the bolt flange connection system under actual working conditions, the accuracy of the evaluation of the sealing performance and the prediction of the service life of the bolt flange connection system is improved.

[0098] The measuring device can further carry out single factor or multi-factor (temperature fluctuation, medium pressure fluctuation, mechanical vibration of different frequencies and amplitudes, bending moment of different sizes) influence test on the leakage rate of the bolt flange connection system. The leakage rate of the bolt flange connection system under the conditions of temperature fluctuation, medium pressure fluctuation, bending moment and mechanical vibration is measured, so as to study the influence of different working conditions on the leakage rate of the bolt flange connection system.

[0099] Example four

[0100] The application simulates the bolt flange connection system leakage rate detection method under multiple working conditions, and comprises the following steps:

[0101] Step 1), installation of the measuring device:

[0102] 1.1) Install the ball universal shaft 19 at the bottom of the lower head 18 under the lower pipeline, and then install the universal wheel 20;

[0103] 1.2) Install the test gasket 23 on the lower flange 6 of the bolt flange connection system;

[0104] 1.3) Install the upper flange 5 on the lower flange 6;

[0105] 1.4) Install the strain gauge 25 and the first temperature sensor 24, and the connecting wires of the strain gauge 25 and the first temperature sensor 24 are led out through the wire outlet hole A at the bottom of the drain cover rack 10;

[0106] 1.5) Install the drain cover gasket 9 on the drain cover rack 10;

[0107] 1.6) Install the drain cover 32, place the O-shaped sealing ring 33 in the O-shaped sealing ring pressing groove, press it through the heat insulation sleeve 3 and the O-shaped ring pressing sleeve 4, and seal the wire outlet hole A at the bottom of the drain cover rack 10 to ensure the good sealing performance of the drain cover 32;

[0108] 1.7) Fix the bracket including the upper and lower fixing brackets, fix the left sides of the upper fixing bracket 36 and the lower fixing bracket 27 with the steel frame 29, then move the above-mentioned installed device into the clasp of the fixing bracket, fix the clasp to ensure the good stability of the device and prepare for subsequent application of bending moment and mechanical vibration;

[0109] 1.8) Install the electro-hydraulic servo actuator 30 on the steel frame 29;

[0110] 1.9) Fix the clasp of the load loading arm 34 on the upper pipeline 1 and the lower pipeline 22, and install the load loading arm 34 on the electro-hydraulic servo actuator 30;

[0111] 1.10) Insert the resistance wire heater 21 into the sealed inner cover body 35 from top to bottom, and place it on the top end of the upper pipeline 1 by means of the flange structure of the resistance wire heater 21, and the wire is led out from the top;

[0112] 1.11) Connect the connecting wires of the strain gauge 25 and each temperature sensor with the data collector 26, connect the liquid crystal control panel 31 with the electro-hydraulic servo actuator 30, and connect the wire of the resistance wire heater 21 with the temperature control instrument 37;

[0113] 1.12) Connect the medium supply system with the inlet pipeline 17;

[0114] 1.13) Connect the leak rate detection system to the gas leak detection pipeline 11;

[0115] Step 2, gas medium supply:

[0116] 2.1) Open the valve of the gas cylinder 13 to make the gas medium flow into the pipeline;

[0117] 2.2) Open the pressure reducing valve 14 to reduce the pressure of the gas medium, make the gas medium flow into the pressure stabilizing tank 15, and stabilize the pressure of the gas medium;

[0118] Step 3, test condition adjustment:

[0119] 3.1) Open the electro-hydraulic servo actuator 30 and the liquid crystal control panel 31, the electro-hydraulic servo actuator 30 applies a predetermined size of external force to the bolt flange connection system through the load loading arm 34, and a vibration with a predetermined frequency and amplitude;

[0120] 3.2) Calibrate the volume of the sealed leak collection cavity to obtain the volume V1 of the sealed leak collection cavity, the pipeline volume V2 between the gas leak detection pipeline 11 and the inlet side of the heat exchanger 39, and the pipeline volume V3 between the outlet side of the heat exchanger 39 and the three-way valve 41;

[0121] 3.3) Open the data acquisition and analysis system to ensure that each sensor is operating normally;

[0122] 3.4) Connect the resistance wire heater 21 to the power supply, and adjust the resistance wire heater 21 through the temperature controller 37 to heat the sealed test cavity;

[0123] 3.5) Adjust the medium supply system to make the pressure in the medium sealing system reach the preset pressure and realize the fluctuation of the pressure in the medium sealing system by adjusting the intelligent electric control valve 16;

[0124] Step 4, leakage medium measurement:

[0125] 4.1) Collect and analyze the temperature data of each temperature sensor in the system, and the bolt load data measured by the strain gauge 25 on each flange bolt 7;

[0126] 4.2) Select the appropriate leak detection method according to the size of the leakage rate, such as helium mass spectrometry leak detection method, U-tube leak detection method or leak collection cavity pressurization method;

[0127] Step 5, end the experiment:

[0128] 5.1) After the test is completed, first close the medium supply system, and then exhaust the high-pressure gas in the sealing system;

[0129] 5.2) Turn off the power supply and cool down the device;

[0130] 5.3) Remove the heating temperature control system, load applying system and medium sealing system to replace the test gasket 23 for the next test.

[0131] The simulated bolted flange connection system of the present application is used to simulate the real working condition of the bolted flange connection system under the temperature, medium pressure fluctuation, external bending moment and vibration, and the leakage rate is measured, which can guide the replacement cycle of the gasket in industry.

[0132] Example Five:

[0133] A further optional design of the present example is that, in the Figure 3 , the test steps measured by the helium mass spectrometry leak detection method are as follows:

[0134] 1) Open the exhaust passage of the three-way valve 41 to discharge the leakage gas medium from the exhaust passage of the three-way valve 41 to the outside;

[0135] 2) Open the second exhaust valve 45, and close the first exhaust valve 42 and the third exhaust valve 47;

[0136] 3) Open the three-way valve 41 to connect the front and rear gas leak detection pipelines 11, and the gas medium is sucked into the helium mass spectrometry leak detector 46 through the gas leak detection pipeline 11 by the suction nozzle of the helium mass spectrometry leak detector 46;

[0137] 4) Observe the reading change of the helium mass spectrometry leak detector 46 and record the leakage rate.

[0138] Example Six:

[0139] A further optional design of the present example is that, since the present application needs to simulate the high temperature working condition, and the accuracy of the pressure drop method will be affected under the high temperature working condition, the collection of leakage cavity pressurization method is more accurate to measure the leakage rate. In the Figure 3 , the test steps measured by the collection of leakage cavity pressurization method of the present example are as follows:

[0140] 1) Open the exhaust passage of the three-way valve 41 to discharge the leakage gas medium from the exhaust passage of the three-way valve 41 to the outside;

[0141] 2) Open the third exhaust valve 47, and close the first exhaust valve 42 and the second exhaust valve 45;

[0142] 3) Open the three-way valve 41 to connect the front and rear gas leak detection pipelines 11, and start timing, and use the micro pressure sensor 44 to measure the pressure of the medium at the outlet of the gas leak detection pipeline 11;

[0143] 4) The first temperature sensor 24 measures the temperature T1 of the test gasket 23;

[0144] 5) The second temperature sensor 38 measures the temperature T2 of the gas medium at the inlet of the heat exchanger 39;

[0145] 6) The third temperature sensor 40 measures the temperature T3 of the gas medium at the outlet of the heat exchanger 39;

[0146] 7) The data collector 26 in the data acquisition and analysis system collects data and records the test data;

[0147] 8) The volumes V1, V2 and V3 and the temperatures T1, T2 and T3 are substituted into the ideal gas state equation, the total number of moles of the sealed set leakage cavity is obtained according to the ideal gas state equation, and the number of moles of the leaked medium is converted into the volume under standard conditions, so as to measure the size of the gas volume leakage rate per unit time.

[0148] Example Seven:

[0149] The further optional design of the example is that, in the Figure 3 , the test steps measured by the U-shaped tube leak detection method are as follows:

[0150] 1) Open the exhaust passage of the three-way valve 41, so that the leaked gas medium is discharged from the exhaust passage of the three-way valve 41 to the outside;

[0151] 2) Open the first exhaust valve 42, and close the second exhaust valve 45 and the third exhaust valve 47;

[0152] 3) Open the three-way valve 41 to make the front and rear gas leak detection pipelines 11 communicate, start timing, and observe the height difference between the two sides of the U-shaped tube 43;

[0153] 4) The size of the leakage rate is calculated by observing the change of the liquid height difference between the two sides of the U-shaped tube 43.

Claims

1. A device for detecting the leakage rate of a bolted flange connection system under simulated multiple working conditions, comprising a medium supply system, a medium sealing system, a leakage rate detection system, a load application system, a heating and temperature control system, and a data acquisition and analysis system, characterized in that: The medium sealing system comprises a bolt flange connection system, a sealing outer cover and a sealing inner cover (35), wherein the sealing outer cover covers the outside of the sealing inner cover (35), and a sealing test chamber is formed between the two covers; the sealing outer cover is provided with an upper pipe (1) and a lower pipe (22), which are connected by the bolt flange connection system, and a test gasket (23) is provided at the flange matching position; The leakage rate detection system comprises a leakage collecting cover (32), a leakage collecting sealing assembly, a gas leakage detection pipeline (11) and a leakage detection device (12); the leakage collecting cover (32) is covered on the outside of the bolt flange connection system; the upper end of the leakage collecting cover (32) is connected to the upper pipeline (1) of the sealing outer cover body through the leakage collecting sealing assembly; the lower end of the leakage collecting cover (32) is sealedly connected to the leakage collecting cover stand (10) through the leakage collecting cover bolts (8); and the leakage collecting cover stand (10) is welded to the outside of the lower pipeline (22) of the sealing outer cover body; The load application system is used to apply mechanical vibration and external bending moment to the bolt flange connection system, and includes an electro-hydraulic servo actuator (30) and two load loading arms (34). The two load loading arms (34) are respectively connected to the upper pipe (1) and the lower pipe (22) of the sealed outer cover. The bottom of the pipe lower head (18) of the lower pipe (22) is also provided with a universal wheel (20) for rolling support. The leakage collection and sealing component of the leakage rate detection system comprises a vacuum insulation sleeve (2), an insulation sleeve (3), an O-ring (33) and an O-ring pressing sleeve (4); the vacuum insulation sleeve (2) is welded to the outside of the upper pipe (1) of the sealing outer cover; a vacuum insulation cavity is provided in the vacuum insulation sleeve (2); an insulation sleeve (3) is provided on the outside of the vacuum insulation sleeve; O-ring pressing grooves are provided on the mating surfaces of the insulation sleeve (3) and the O-ring pressing sleeve (4); the O-ring (33) is installed between the insulation sleeve (3) and the O-ring pressing sleeve (4) through the O-ring pressing groove; and the outside of the O-ring pressing sleeve (4) is welded to the leakage collection cover (32) as a whole; The heating and temperature control system comprises a temperature controller (37) and a resistance wire heater (21) arranged in a sealed inner cover (35). The resistance wire heater (21) is inserted into the sealed inner cover (35) from top to bottom and is installed at the top of the upper pipe (1).

2. The device for detecting leakage rate of a bolted flange connection system under simulated multiple working conditions according to claim 1, characterized in that: The medium supply system is used to deliver gaseous medium to the medium sealing system, and comprises a gas cylinder (13), a pressure reducing valve (14), a pressure stabilizing tank (15), an intelligent electric control valve (16) and an air intake pipe (17) which are connected in sequence.

3. The device for detecting leakage rate of a bolted flange connection system under simulated multiple working conditions according to claim 2, characterized in that: The data acquisition and analysis system includes a first temperature sensor (24) arranged outside a test gasket (23), a second temperature sensor (38) arranged at an inlet of a heat exchanger (39), a third temperature sensor (40) arranged at an outlet of the heat exchanger (39), and a strain gauge (25) arranged in a bolt flange connection system.

4. The device for detecting leakage rate of a bolted flange connection system under simulated multiple working conditions according to claim 3 is characterized in that: There are eight strain gauges (25) in total, which are respectively welded on eight flange bolts (7) of the bolt flange connection system and are used to measure the bolt stress of each flange bolt (7) when loaded.

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