Helium leak detection device and method for molten salt check valve

Abstract

The invention discloses a molten salt check valve helium leak detection device and method, and belongs to the technical field of molten salt check valves. The problems that in the prior art, leakage rate detection is inaccurate, and the leakage position is difficult to find are solved. According to the technical scheme, a helium source is sequentially connected with a first pressure gauge and a spray gun, the left side of a fused salt check valve is connected with a helium mass spectrometer leak detector and an auxiliary vacuum pump, and the right side of the fused salt check valve is sequentially connected with a second pressure gauge, a second electric stop valve, a second quick cut-off valve and a second release valve; and a calibration leak hole is formed in the fused salt check valve. According to different use conditions, a proper detection method can be selected to determine the leakage amount of a leakage point, and if a vacuum leakage detection test exceeds the standard, the method is continued to find out the position of the leakage point, so that repair is facilitated; detection cost is low, and equipment is simple; detection results are visual, and leakage positions are easy to judge.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of molten salt check valve, in particular to a device and method for helium leak detection of molten salt check valve. BACKGROUND

[0002] The molten salt is generally sodium nitrate and potassium nitrate mixed in a ratio of 6:4, which is used as a high-temperature heat storage medium and widely applied in the fields of photo-thermal power generation, nuclear industry, chemical high-temperature reaction system, etc. The working temperature of the molten salt is usually 200-600℃, and the molten salt has the characteristics of strong corrosion, high viscosity, etc. The molten salt solidifies below 220℃ and has strong oxidizing property at high temperature. The molten salt check valve is a key component for preventing medium backflow and protecting equipment safety in the system. Once a leakage occurs, it will cause multi-dimensional and chain-type hazards.

[0003] The check valve belongs to the automatic valve type, which is opened and closed by relying on the flow of the medium itself to overcome the gravity of the valve disc, and is a valve for preventing fluid medium backflow. The check valve is widely applied in the fields of thermal power, nuclear power, petroleum, etc. According to the movement form of the valve disc, the check valve can be divided into the lift check valve and the swing check valve.

[0004] The existing molten salt check valve detection technology needs to stop and disassemble the valve, which affects the continuous operation of the system. The water pressure gas test can only detect macroscopic leakage and cannot find small leakage. After detection, the inside of the valve needs to be dried, which increases the process and requires high skills of the operator. Moreover, the dynamic leakage in the running state cannot be detected. The inside leakage of the valve cannot be detected, only the external leakage can be monitored. The installation and maintenance are complex, the sensors need to be arranged around the valve, and the service life of the sensors is short in the high-temperature environment. The offline detection affects the operation efficiency, and the online detection is high in cost and easy to be disturbed.

[0005] Therefore, it is urgent to provide a device and method for helium leak detection of molten salt check valve to solve the problems of inaccurate leakage rate detection and difficult leakage position finding in the prior art. SUMMARY

[0006] In view of the above facts, the present application is designed to solve the problems of inaccurate leakage rate detection and difficult leakage position finding in the prior art, and further provides a device and method for helium leak detection of molten salt check valve.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0008] Scheme one: a device for helium leak detection of molten salt check valve, comprising a helium source, a first pressure gauge, a spray gun, a second pressure gauge, a helium mass spectrometer leak detector;

[0009] The helium source is connected with the first pressure gauge and the spray gun in sequence. The left side of the molten salt check valve is connected with the helium mass spectrometer leak detector and an auxiliary vacuum pump. The right side of the molten salt check valve is connected with the second pressure gauge, a second electric shut-off valve, a second quick shut-off valve and a second relief valve in sequence.

[0010] The calibration leak hole is arranged on the molten salt check valve.

[0011] Further, the first stop valve is arranged between the helium source and the first pressure gauge, and the first pressure gauge is sequentially arranged between the first spray gun and the first relief valve, the first quick cut-off valve and the first electric stop valve.

[0012] Further, the calibration leak hole is a helium permeation type standard leak hole.

[0013] Scheme two: a method for helium leak detection of a molten salt check valve, using a device for helium leak detection of a molten salt check valve as described in scheme one, specifically:

[0014] Step one: connect the molten salt check valve with the helium leak detection device, start the helium mass spectrometer leak detector, adjust the parameters to make it in working condition, and start the auxiliary vacuum pump to pump the molten salt check valve to vacuum;

[0015] Step two: open the leak detection valve of the helium mass spectrometer leak detector to make the helium mass spectrometer leak detector communicate with the molten salt check valve, and record the value after the output of the helium mass spectrometer leak detector is stable, which is the background I0;

[0016] Step three: after the background I0 measurement is completed, open the calibration leak hole, and record the value after the output of the helium mass spectrometer leak detector is stable, which is the calibration leak hole leak rate I1;

[0017] Step four: after the calibration leak hole leak rate I1 measurement is completed, close the calibration leak hole, and use the helium blowing method to detect the molten salt check valve, record the value after the output of the helium mass spectrometer leak detector is stable, which is the stable value I2, I2-I0 is the leak gas signal generated by the leak point, and the leakage rate is calculated.

[0018] Further, in step one, if the helium mass spectrometer leak detector cannot start normally, the auxiliary vacuum pump needs to be started, and the auxiliary vacuum pump is closed as small as possible under the premise that the helium mass spectrometer leak detector works normally.

[0019] Further, in step four, when the molten salt check valve is detected by the helium blowing method, the detection is from top to bottom, the helium blowing direction is opposite to the moving direction of the spray gun, the spray gun is upward, and the horizontal leak point is detected from near to far.

[0020] Further, the moving speed of the spray gun is less than 3 times the reaction time, and the moving speed is less than 3 mm / s.

[0021] The distance between the spray gun and the detected surface is within 3 mm.

[0022] Further, before the leak detection, the inner and outer surfaces of the molten salt check valve are cleaned, the oxide scale is removed and the passivation treatment is performed, the grease is removed and kept dry, and the inside is dried by oil-free hot air or surface heat.

[0023] Further: in the fourth step, when the helium mass spectrometer output indicates rising, immediately move away the spray gun, and after the output indicates falling, spray helium again, and confirm and observe whether the output indicates rising again, and repeat several times to verify whether there is leakage, and if a leakage point is found, mark beside the leakage point.

[0024] Further: in the fourth step, the formula for calculating the leakage rate Q is:

[0025] ;

[0026] Q0=7.5*10-6Pa·m3 / s. -10 3

[0027] The beneficial effects of the present application are:

[0028] 1. The present application can select appropriate detection methods according to different use conditions to determine the leakage amount of the leakage point, and if the vacuum leakage detection test is out of standard, continue the method to find the leakage point position, and facilitate repair.

[0029] 2. The present application has low detection cost and simple equipment.

[0030] 3. The detection result of the present application is intuitive and easy to judge the leakage position. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the overall structure diagram of the present application;

[0032] Figure 2 is the device diagram of example 3.

[0033] In the figure: 1-helium source, 2-first stop valve, 3-first pressure gauge, 4-first bleed valve, 5-first quick cut-off valve, 6-first electric stop valve, 7-spray gun, 8-fused salt check valve, 9-second pressure gauge, 10-second electric stop valve, 11-second quick cut-off valve, 12-second bleed valve, 13-assistant vacuum pump, 14-helium mass spectrometer. DETAILED DESCRIPTION

[0034] In order to enable the personnel in the technical field to better understand the present application scheme, the technical scheme in the present application embodiment will be described clearly and completely in combination with the drawings in the present application embodiment. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor shall belong to the scope of protection of the present application.

[0035] ​​The terms "set", "connected", "fixed" should be interpreted broadly. For example, "connected" can be fixed connection, detachable connection, or integral structure; can be mechanical connection, can be directly connected, or indirectly connected through intermediate medium, or internal communication between two devices, elements or components. The specific meaning of the above terms in the present application can be understood according to the specific circumstances by those skilled in the art.

[0036] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0037] The preferred embodiments of the present application will be described in detail below with reference to the drawings.

[0038] Embodiment 1: Reference Figure 1 To explain this embodiment in detail, the device for helium leak detection of a fused salt check valve in this embodiment comprises a helium source 1, a first pressure gauge 3, a spray gun 7, a second pressure gauge 9, a helium mass spectrometer leak detector 14;

[0039] The helium source 1 is connected to the first pressure gauge 3 and the spray gun 7 in sequence, the left side of the fused salt check valve 8 is connected to the helium mass spectrometer leak detector 14 and an auxiliary vacuum pump 13, and the right side of the fused salt check valve 8 is connected to the second pressure gauge 9, a second electric shut-off valve 10, a second quick shut-off valve 11 and a second relief valve 12 in sequence.

[0040] A calibrated leak hole is arranged on the fused salt check valve 8.

[0041] More specifically, the first shut-off valve 2 is arranged between the helium source 1 and the first pressure gauge 3, and a first relief valve 4, a first quick shut-off valve 5 and a first electric shut-off valve 6 are arranged between the first pressure gauge 3 and the spray gun 7 in sequence.

[0042] More specifically, the calibrated leak hole is a helium permeation type standard leak hole.

[0043] Embodiment 2: A method for helium leak detection of a fused salt check valve, which adopts the device for helium leak detection of a fused salt check valve as described in embodiment 1, specifically:

[0044] Step one: connect the fused salt check valve 8 with the helium leak detection device, start the helium mass spectrometer leak detector 14, adjust the parameters to make it in working condition, and start the auxiliary vacuum pump 13 to vacuumize the fused salt check valve 8;

[0045] Step two: open the leak detection valve of the helium mass spectrometer leak detector 14 to make the helium mass spectrometer leak detector 14 communicate with the fused salt check valve 8, and record the value after the output of the helium mass spectrometer leak detector 14 is stable, which is the background I0.

[0046] Step three: after the background I0 measurement is completed, open the calibration leak, and record the value output by the helium mass spectrometer 14 after it stabilizes, which is the calibration leak rate I1;

[0047] Step four: after the calibration leak rate I1 measurement is completed, close the calibration leak, and use the helium sparging method to detect the molten salt check valve 8, and record the value output by the helium mass spectrometer 14 after it stabilizes, which is the stable value I2, I2-I0 is the leak gas signal generated by the leak point, and the leakage rate is calculated.

[0048] More specifically: in step one, if the helium mass spectrometer 14 cannot start normally, the auxiliary vacuum pump 13 needs to be turned on, and the auxiliary vacuum pump 13 is turned off as much as possible under the premise that the helium mass spectrometer 14 works normally.

[0049] More specifically: in step four, when the helium sparging method is used to detect the molten salt check valve 8, it is detected from top to bottom, the helium sparging direction is opposite to the moving direction of the spray gun 7, the spray gun 7 is upward, and the horizontal leak point is detected from near to far.

[0050] More specifically: the moving speed of the spray gun 7 is less than 3 times the reaction time, and the moving speed is less than 3 mm / s.

[0051] More specifically: the distance between the spray gun 7 and the detected surface is within 3 mm.

[0052] More specifically: in step four, when the output of the helium mass spectrometer 14 indicates an increase, immediately move the spray gun 7 away, and then spray helium after the output indicates a decrease, confirm and observe whether the output indicates an increase again, and repeatedly verify whether there is a leak. If a leak point is found, mark beside the leak point.

[0053] More specifically: in step four, the formula for calculating the leakage rate Q is:

[0054] ;

[0055] Wherein: Q0 is the leakage rate of the calibration leak, which is 7.5x10 -10 Pa·m 3 / s.

[0056] More specifically: before leak detection, clean the inner and outer surfaces of the molten salt check valve 8, remove the oxide scale and passivate, remove grease and keep dry, and use oil-free hot air drying or surface heat drying inside.

[0057] More specifically: after passing the required water pressure test or air pressure test, only when the design specifies, the molten salt check valve 8 can be evacuated, and the opening of the molten salt check valve 8 and the sealing plate or blind plate of the measuring device should meet the same sealing requirements as the molten salt check valve 8 itself;

[0058] The molten salt check valve 8 and the measuring device should be cleaned inside and outside, and the inner and outer surfaces should be degreased and dried.

[0059] More specifically, the helium gas is an industrial helium with a concentration of 97%.

[0060] In step four, helium gas blowing method can be used to detect leaks in the molten salt check valve 8, or the molten salt check valve 8 and the helium leak detection device are completely put into the plastic bag filled with helium, or the suspicious area is packaged with a plastic bag filled with helium, and the three methods are combined two by two or from the whole to the local and then the accurate detection is carried out.

[0061] Example 3: Test of the molten salt check valve 8 Figure 2 Test whether there is a leak between the valve body and the valve cover of the valve, and the measured I0 is 3.7x10 -10 Pa·m 3 / s, I1 is 4.3x10 -10 Pa·m 3 / s, I2 is 6.2x10 -10 Pa·m 3 / s, and the formula gives Q as 3.1x10 - 9 Pa·m 3 / s.

[0062] Finally, it should be pointed out that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, the technical solutions described in the foregoing examples can be modified, or some or all of the technical features can be replaced by equivalents; as long as there is no structural conflict, each feature in the specific embodiments disclosed in the present application can be used in combination with any other feature, and the corresponding technical solution will not deviate from the scope of the technical solutions of the present application.

[0063] In addition, it should be understood that although the present specification is described in terms of embodiments, each embodiment does not contain only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be combined appropriately to form other embodiments that those skilled in the art can understand.

Claims

1. A device for helium leak detection of a molten salt check valve, comprising: It comprises a helium source (1), a first pressure gauge (3), a spray gun (7), a second pressure gauge (9), a helium mass spectrometer leak detector (14); The helium source (1) is sequentially connected with the first pressure gauge (3) and the spray gun (7), the left side of the molten salt check valve (8) is connected with the helium mass spectrometer leak detector (14) and an auxiliary vacuum pump (13), and the right side of the molten salt check valve (8) is sequentially connected with the second pressure gauge (9), a second electric shut-off valve (10), a second quick cut-off valve (11) and a second relief valve (12). A calibration leak hole is arranged on the molten salt check valve (8).

2. The device for helium leak detection of a fused salt check valve according to claim 1, wherein, The first shut-off valve (2) is arranged between the helium source (1) and the first pressure gauge (3), the first pressure gauge (3) and the spray gun (7) are sequentially provided with a first relief valve (4), a first quick cut-off valve (5) and a first electric shut-off valve (6).

3. The device for helium leak testing of a molten salt check valve of claim 1, wherein, The calibration leak hole adopts a helium permeation type standard leak hole.

4. A method for helium leak detection of a molten salt check valve using the apparatus for helium leak detection of a molten salt check valve according to claim 1, wherein Specifically, Step one: connect the molten salt check valve (8) with the helium leak detection device, start the helium mass spectrometer leak detector (14), adjust the parameters to make it in the working state, and start the auxiliary vacuum pump (13) to vacuumize the molten salt check valve (8); Step two: open the leak detection valve of the helium mass spectrometer leak detector (14) to make the helium mass spectrometer leak detector (14) communicate with the molten salt check valve (8), and record the output of the helium mass spectrometer leak detector (14) after it is stabilized, which is the background I0; Step three: after the background I0 is measured, open the calibration leak hole, and record the output of the helium mass spectrometer leak detector (14) after it is stabilized, which is the calibration leak hole leak rate I1; Step four: after the calibration leak hole leak rate I1 is measured, close the calibration leak hole, and use the helium blowing method to detect the molten salt check valve (8), record the output of the helium mass spectrometer leak detector (14) after it is stabilized, which is the stable value I2, I2-I0 is the leakage signal of the leak point, and the leakage rate is calculated.

5. The method of claim 4, wherein the molten salt check valve is helium leak tested. In step one, if the helium mass spectrometer leak detector (14) cannot normally start working, the auxiliary vacuum pump (13) needs to be started, and the auxiliary vacuum pump (13) is as small as possible under the premise that the helium mass spectrometer leak detector (14) normally works.

6. The method of claim 4, wherein the molten salt check valve is helium leak tested. In step four, when the molten salt check valve (8) is detected by the helium blowing method, it is detected from top to bottom, the helium blowing direction is opposite to the moving direction of the spray gun (7), the spray gun (7) faces upward, and the horizontal leak point is detected from near to far.

7. The method of claim 6, wherein the molten salt check valve is helium leak tested. The moving speed of the spray gun (7) is less than 3 times the reaction time, and the moving speed is less than 3 mm / s. The distance between the spray gun (7) and the detected surface is within 3 mm.

8. The method of claim 4, wherein the molten salt check valve is helium leak tested. Before leak detection, the inner and outer surfaces of the molten salt check valve (8) are cleaned, the oxide scale is removed, and the passivation treatment is performed, the grease is removed and kept dry, the inside is dried by oil-free hot air or the surface is heated.

9. The method of claim 4, wherein the molten salt check valve is helium leak tested. In step four, when the output of the helium mass spectrometer leak detector (14) indicates an increase, the spray gun (7) is immediately moved away, the helium is sprayed again after the output indicates a decrease, it is confirmed and observed whether the output indicates an increase again, and it is repeatedly verified whether there is a leak, and if a leak point is found, it is marked beside the leak point.

10. The method of claim 4, wherein the molten salt check valve is helium leak tested. In step four, the formula for calculating the leakage rate Q is: ； wherein: Q0 is the calibrated leak rate of the leak, which is 7.5 x 10 -10 Pa·m 3 / s.

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