A method for establishing a standard curve of helium content in neon gas, a method for detecting helium content in neon gas, and a detection device

Abstract

The present invention provides a method for establishing a standard curve of helium content in neon gas, a method for detecting the helium content in neon gas, and a detection device, which relate to the technical field of analytical detection. The method for establishing a standard curve of helium content in neon gas provided by the present invention includes the following steps: mixing the neon gas to be measured and a helium standard gas in neon to obtain a series of helium standard gases with different concentrations; the concentration difference between the series of helium standard gases with different concentrations and the neon gas to be measured is the increased concentration of helium; using a helium mass spectrometer leak detector to detect the series of helium standard gases with different concentrations to obtain the response values of the series of helium standard gases with different concentrations; taking the increased concentration of helium as the abscissa and the response values of the series of helium standard gases with different concentrations as the ordinate to obtain a standard curve of the response value and the increased concentration of helium. The standard curve established by using the method provided by the present invention can achieve a detection limit of 0.1 ppm, and has high accuracy and good precision.

Description

Technical Field

[0001] The present invention relates to the technical field of analytical detection, and particularly relates to a method for establishing a standard curve of helium content in neon gas, a method for detecting helium content in neon gas, and a detection device. Background Art

[0002] Neon is a colorless, odorless, non-flammable noble gas with the chemical formula Ne. Usually, neon can be used as the filling gas for colored neon lights for outdoor advertising displays, and can also be used for visible light-emitting indicator lights, voltage regulation, and components of laser mixtures.

[0003] The preparation method of neon is the air separation method: crude helium and neon mixture are extracted from the air separation device. The crude helium and neon mixture is obtained with a pure neon-helium mixture with a purity of more than 99.95% after removing hydrogen and nitrogen, and high-purity neon with a purity of 99.99% can be prepared through separation and purification.

[0004] Helium is an inert gas with the chemical formula He. At room temperature, it is an extremely light colorless, odorless, and tasteless monatomic gas. The chemical properties of helium are very inactive, and it is difficult to react with other substances under normal conditions. Therefore, as an impurity existing in neon gas, the main removal method of helium is the rectification method, and it is difficult to remove through a purifier or adsorbent.

[0005] At present, the determination of helium content in neon gas is mainly the thermal conductivity detector gas chromatography method, which requires the use of neon as the carrier gas. However, helium in neon cannot be further removed, which affects the accuracy of the determination result. At the same time, limited by the sensitivity of the thermal conductivity detector, it is difficult to meet the current standards and customer requirements for the detection of helium in neon in terms of both detection limit and accuracy (the detection lower limit of helium content in neon gas detected by the thermal conductivity detector is basically above 2 ppm). Therefore, there is an urgent need for a new and efficient detection method to determine the helium content in neon gas. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for establishing a standard curve of helium content in neon gas, a method for detecting helium content in neon gas, and a detection device. The detection method provided by the present invention can accurately determine the helium content in neon gas, has high sensitivity, high accuracy, and good precision, has a fast response speed, and is simple, quick, and reproducible in operation.

[0007] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0008] The present invention provides a method for establishing a standard curve of helium content in neon gas, including the following steps:

[0009] Mix the neon gas to be measured with the helium standard gas in neon to obtain a series of helium standard gases with different concentrations; the concentration difference between the series of helium standard gases with different concentrations and the neon gas to be measured is the increased concentration of helium.

[0010] Use a helium mass spectrometer leak detector to detect the series of helium standard gases with different concentrations to obtain the response values of the series of helium standard gases with different concentrations.

[0011] Take the increased concentration of helium as the abscissa and the response values of the series of helium standard gases with different concentrations as the ordinate to obtain the standard curve of the response value versus the increased concentration of helium.

[0012] Preferably, the concentration of helium in the helium standard gas in neon is 50 - 1000 ppm.

[0013] Preferably, the series of helium standard gases with different concentrations also includes the neon gas to be measured.

[0014] Preferably, the linear range of the standard curve of the response value versus the increased concentration of helium is 0.1 - 100 ppm.

[0015] The present invention provides a method for detecting the helium content in neon gas, including the following steps:

[0016] Obtain the standard curve of the response value versus the increased concentration of helium according to the method for establishing the standard curve of the helium content in neon gas described in the above technical solution;

[0017] The intercept of the standard curve is the helium content in the neon gas to be measured.

[0018] The present invention provides a method for detecting the helium content in neon gas, including the following steps:

[0019] Use a helium mass spectrometer leak detector to detect the neon gas to be measured to obtain the response value of the neon gas to be measured.

[0020] Substitute the response value of the neon gas to be measured into the standard curve of the response value versus the increased concentration of helium described in the above technical solution to obtain the helium content in the neon gas to be measured.

[0021] The present invention provides a device for detecting the helium content in neon gas, including a neon gas bottle 1 to be measured, a helium standard gas bottle 2 in neon, a gas diluter 3, a high-pressure buffer 4, and a helium mass spectrometer leak detector 5;

[0022] The neon gas bottle 1 to be measured is communicated with the balance gas inlet of the gas diluter 3; the helium standard gas bottle 2 in neon is communicated with the diluting gas inlet of the gas diluter 3;

[0023] The outlet of the gas diluter 3 is communicated with the inlet of the high-pressure buffer 4;

[0024] The detection port of the high-pressure buffer 4 is connected to the gas inlet of the helium mass spectrometer leak detector 5.

[0025] Preferably, a first pressure reducer 6 is further provided between the neon gas cylinder 1 to be measured and the gas dilutor 3; a second pressure reducer 7 is further provided between the helium-in-neon standard gas cylinder 2 and the gas dilutor 3.

[0026] Preferably, the detection device further includes a vacuum pump 9, and the gas inlet of the vacuum pump 9 is connected to the evacuation port of the high-pressure buffer 4.

[0027] Preferably, the helium mass spectrometer leak detector 5 is a helium vacuum mass spectrometer leak detector.

[0028] The present invention provides a method for establishing a standard curve of the helium content in neon gas, including the following steps: mixing the neon gas to be measured and the helium-in-neon standard gas to obtain a series of helium standard gases with different concentrations; the concentration difference between the series of helium standard gases with different concentrations and the neon gas to be measured is the increased concentration of helium; using a helium mass spectrometer leak detector to detect the series of helium standard gases with different concentrations to obtain the response values of the series of helium standard gases with different concentrations; taking the increased concentration of helium as the abscissa and the response values of the series of helium standard gases with different concentrations as the ordinate to obtain the standard curve of the response value and the increased concentration of helium. The standard curve of the helium content in neon gas established by the method provided by the present invention can reach a detection limit of 0.1 ppm, and has high sensitivity, high accuracy and good precision.

[0029] The present invention also provides two detection methods for the helium content in neon gas. The detection methods provided by the present invention can accurately determine the helium content in neon gas, have high sensitivity, high accuracy and good precision, fast response speed, and are simple and quick to operate.

[0030] The present invention provides a detection device for the helium content in neon gas. The present invention uses a gas dilutor to mix the neon gas to be measured and the helium-in-neon standard gas to prepare a series of helium standard gases with different concentrations of the background of the neon gas to be measured, uses a high-pressure buffer to keep the pressure of the neon gas to be measured and the series of helium standard gases with different concentrations always at atmospheric pressure (gauge pressure is 0), and then uses a helium mass spectrometer leak detector to accurately measure the helium content in the series of helium standard gases with different concentrations. The present invention can accurately determine the helium content in neon gas, has high sensitivity, high accuracy and good precision, fast response speed, and is simple and quick to operate, with good accuracy and reproducibility. Description of the Drawings

[0031] Figure 1 It is a detection device for the helium content in neon gas. Figure 1Among them, 1 is the neon gas cylinder to be measured, 2 is the helium in neon standard gas cylinder, 3 is the gas diluter, 4 is the high-pressure buffer, 5 is the helium mass spectrometer leak detector, 6 is the first pressure reducer, 7 is the second pressure reducer, 8 is the switching valve, 9 is the vacuum pump, and 10 is the three-way valve. Specific implementation mode

[0032] The present invention provides a method for establishing a standard curve of the helium content in neon gas, comprising the following steps:

[0033] Mix the neon gas to be measured and the helium in neon standard gas to obtain a series of helium standard gases with different concentrations; the concentration difference between the series of helium standard gases with different concentrations and the neon gas to be measured is the increased concentration of helium.

[0034] Detect the series of helium standard gases with different concentrations by using a helium mass spectrometer leak detector to obtain the response values of the series of helium standard gases with different concentrations.

[0035] Take the increased concentration of helium as the abscissa and the response values of the series of helium standard gases with different concentrations as the ordinate to obtain the standard curve of the response value and the increased concentration of helium.

[0036] In the present invention, the neon gas to be measured and the helium in neon standard gas are mixed to obtain a series of helium standard gases with different concentrations; the concentration difference between the series of helium standard gases with different concentrations and the neon gas to be measured is the increased concentration of helium. In the present invention, the concentration of helium in the helium in neon standard gas is preferably 50-1000 ppm, more preferably 100-200 ppm. In the present invention, the series of helium standard gases with different concentrations preferably have no less than 5 points. In the present invention, the series of helium standard gases with different concentrations preferably further include the neon gas to be measured. In the present invention, the increased concentration of helium is preferably 0.1-100 ppm. In the present invention, the increased concentration of helium is preferably directly obtained by a gas diluter.

[0037] In the present invention, the pressures of the neon gas to be measured and the helium in neon standard gas are preferably 0.3 MPa.

[0038] In a specific embodiment of the present invention, the neon gas to be measured and the helium in neon standard gas are mixed in a gas diluter. In the present invention, the purge flow rate of the gas diluter is preferably 0.5-3 L / min, more preferably 1-2 L / min; the purge time is preferably 1-5 min, more preferably 2-3 min, so as to ensure the accuracy of the test results. As an embodiment of the present invention, before the neon gas to be measured is introduced into the gas diluter, its pressure is first reduced to 0.3 MPa; before the helium in neon standard gas is introduced into the gas diluter, its pressure is first reduced to 0.3 MPa.

[0039] After obtaining a series of helium standard gases with different concentrations, the present invention uses a helium mass spectrometer leak detector to detect the series of helium standard gases with different concentrations, and obtains the response values of the series of helium standard gases with different concentrations; taking the increased concentration of helium as the abscissa and the response values of the series of helium standard gases with different concentrations as the ordinate, a standard curve of the response value versus the increased concentration of helium is obtained. In a specific embodiment of the present invention, before the series of helium standard gases with different concentrations are detected, it further includes keeping the pressure of the series of helium standard gases with different concentrations at atmospheric pressure all the time. In a specific embodiment of the present invention, the helium mass spectrometer leak detector is a helium vacuum mass spectrometer leak detector.

[0040] In the present invention, the detection conditions of the helium mass spectrometer leak detector preferably include: the molecular turbo pump speed is 1500 r / s, the display lower limit is (set value) 1.0×10 -13 Pa·m 3 / s, the machine factor (set value) is 1.0, the trigger value is 1.0×10 - 6 Pa·m 3 / s, and the indicated value after zeroing in air is less than 1.0×10 -8 Pa·m 3 / s.

[0041] In the present invention, the response value refers to the vacuum degree value of helium response.

[0042] In the present invention, the linear range of the standard curve of the response value versus the increased concentration of helium is preferably 0.1 - 100 ppm.

[0043] In a specific embodiment of the present invention, the linear regression equation of the standard curve is as shown in Equation I:

[0044] y = 2.9428x + 5.005 Equation I;

[0045] x is the increased concentration of helium, with the unit of ppm;

[0046] y is the response value, with the unit of 10 -8 Pa·m 3 / s.

[0047] In the present invention, the R 2 of the standard curve is preferably > 0.99, and more preferably 0.9999.

[0048] The present invention provides a method for detecting the helium content in neon gas, including the following steps:

[0049] Obtain the standard curve of the response value versus the increased concentration of helium according to the method for establishing the standard curve of the helium content in neon gas as described in the above technical solution;

[0050] The intercept of the standard curve is the helium content in the neon gas to be measured.

[0051] In a specific embodiment of the present invention, the intercept 5.005 of the standard curve shown in Formula I is the helium content in the neon gas to be measured, and the unit is ppm.

[0052] The present invention also provides a method for detecting the helium content in neon gas, comprising the following steps:

[0053] Using a helium mass spectrometer leak detector to detect the neon gas to be measured to obtain the response value of the neon gas to be measured;

[0054] Substituting the response value of the neon gas to be measured into the standard curve of the response value and the concentration increase of helium in the above technical solution to obtain the helium content in the neon gas to be measured.

[0055] The present invention provides a device for detecting the helium content in neon gas, comprising a neon gas cylinder to be measured, a standard helium-in-neon gas cylinder, a gas diluter, a high-pressure buffer, and a helium mass spectrometer leak detector;

[0056] The neon gas cylinder to be measured is connected to the balance gas inlet of the gas diluter; the standard helium-in-neon gas cylinder is connected to the diluting gas inlet of the gas diluter;

[0057] The outlet of the gas diluter is connected to the inlet of the high-pressure buffer;

[0058] The detection port of the high-pressure buffer is connected to the inlet of the helium mass spectrometer leak detector.

[0059] As an embodiment of the present invention, the detection device further includes a first pressure reducer disposed between the neon gas cylinder to be measured and the gas diluter for reducing the pressure of the neon gas to be measured.

[0060] As an embodiment of the present invention, the detection device further includes a second pressure reducer disposed between the standard helium-in-neon gas cylinder and the gas diluter for reducing the pressure of the standard helium-in-neon gas.

[0061] As an embodiment of the present invention, the detection device further includes a switching valve disposed between the gas diluter and the high-pressure buffer for controlling the gas flow rate.

[0062] In the present invention, the volume of the high-pressure buffer is preferably 0.5 - 10 L, more preferably 1 - 2 L. As an embodiment of the present invention, the high-pressure buffer is further provided with an automatic pressure exhaust valve for automatically exhausting when the pressure is higher than the atmospheric pressure. As an embodiment of the present invention, the high-pressure buffer is further provided with a pressure gauge.

[0063] As an embodiment of the present invention, the detection device further includes a vacuum pump, and the air inlet of the vacuum pump is communicated with the evacuation port of the high-pressure buffer. The present invention utilizes the vacuum pump to evacuate the gas in the high-pressure buffer, quickly replace the gas in the high-pressure buffer, and ensure the accuracy and precision of the test results. As an embodiment of the present invention, the detection device further includes a three-way valve disposed between the vacuum pump and the high-pressure buffer. In the present invention, the function of the three-way valve is to quickly relieve the pressure of the high-pressure buffer cavity and protect the vacuum pump.

[0064] As an embodiment of the present invention, the detection device further includes a switching valve disposed between the high-pressure buffer and the helium mass spectrometer leak detector for controlling the gas flow rate.

[0065] In the present invention, the helium mass spectrometer leak detector is preferably a helium vacuum mass spectrometer leak detector. In the present invention, the response value range of the helium mass spectrometer leak detector is 10 -5 ~10 -13 Pa·m 3 / s. In the present invention, the gas inlet of the helium mass spectrometer leak detector is preferably the air inlet of the suction gun.

[0066] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0067] Example 1

[0068] (1) Connect the outlet of the neon gas cylinder 1 to be tested to the first pressure reducer 6, and perform replacement on the first pressure reducer 6 by means of lifting and lowering the pressure, with the replacement times being 10 times. Connect the 100 ppm helium in neon standard gas cylinder 2 to the second pressure reducer 7, and perform the same replacement on the second pressure reducer 7;

[0069] (2) Connect the outlet end of the first pressure reducer 6 to the balance gas inlet of the gas dilutor 3, connect the outlet end of the second pressure reducer 7 to the diluting gas inlet of the gas dilutor 3, and connect the outlet of the gas dilutor 3 to the gas inlet of the high-pressure buffer 4 with a volume of 1 L;

[0070] (3) Open the cylinder valves of the neon gas cylinder 1 to be tested and the helium standard gas cylinder 2 in 100 ppm neon. Use the first pressure reducer 6 and the second pressure reducer 7 to adjust the pressure to 0.3 MPa. Turn on the power of the gas diluter 3 and prepare a series of helium standard gases with different concentrations according to the operation of the gas diluter 3. The increased concentration of helium compared to the neon gas to be tested is shown in Table 1. Then, successively introduce the series of helium standard gases with different concentrations into the high-pressure buffer 4 and perform replacement through the evacuation port. First, evacuate for 30 s before replacement, then turn off the vacuum pump 9. The replacement flow rate is 2 L / min. Open the three-way valve 10 and repeat the evacuation and replacement 3 times, then perform stable purging for 2 min, and then adjust the inlet gas flow rate of the high-pressure buffer 4 to 100 mL / min.

[0071] (4) Connect the suction gun of the helium vacuum mass spectrometer leak detector 5 to the detection port of the high-pressure buffer 4, and detect the series of helium standard gases with different concentrations according to the above operations. Record the response values and establish a standard curve based on the helium concentration values and response values of the series of helium standard gases with different concentrations, so as to obtain the helium content in the neon gas to be tested.

[0072] 1. Experimental results

[0073] Obtained from the intercept of the standard curve.

[0074] 2. Linearity experiment

[0075] Perform a linearity experiment with 11 concentration points using the method in Example 1. The correlation coefficient R 2 = 0.9998. The measured helium content in neon is 5.00 ppm. The experimental data for 11 concentration points are shown in Table 1.

[0076] Table 1 Experimental data for 11 concentration points

[0077]

[0078] 3. Accuracy verification

[0079] Use the 20 ppm helium standard gas (actual concentration is 25.00 ppm) diluted in Example 1 as the gas to be measured, and use the method in GB / T 17873-2014 Pure Neon and High-Purity Neon to test the helium content in neon. The test result is 26 ppm.

[0080] It can be seen that the test results obtained by using the method in the national standard and the test results obtained by using the method of the present invention are very close, indicating that the method of the present invention is accurate and reliable and can be used instead of the method in the above standard.

[0081] The detection method provided by the present invention has high sensitivity and low detection limit for helium in neon. The lower detection limit reaches 0.1 ppm, which is better than 0.5 ppm of the national standard method. Moreover, no carrier gas is required, the response time can be as low as 5 s, and it also has high stability and response speed, and is easy to operate and implement.

[0082] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for establishing a standard curve of helium content in neon gas, characterized in that, it includes the following steps: Mix the neon gas to be measured and the helium standard gas in neon to obtain a series of helium standard gases with different concentrations; the concentration difference between the series of helium standard gases with different concentrations and the neon gas to be measured is the increased concentration of helium; Use a helium mass spectrometer leak detector to detect the series of helium standard gases with different concentrations to obtain the response values of the series of helium standard gases with different concentrations; Take the increased concentration of helium as the abscissa and the response values of the series of helium standard gases with different concentrations as the ordinate to obtain the standard curve of the response value and the increased concentration of helium; The device used in the establishment method includes a neon gas cylinder to be measured (1), a helium standard gas cylinder in neon (2), a gas diluter (3), a high-pressure buffer (4) and a helium mass spectrometer leak detector (5); The equilibrium gas inlet of the neon gas cylinder to be measured (1) is connected to the equilibrium gas inlet of the gas diluter (3); the dilution gas inlet of the helium standard gas cylinder in neon (2) is connected to the dilution gas inlet of the gas diluter (3); The gas outlet of the gas diluter (3) is connected to the gas inlet of the high-pressure buffer (4); The detection port of the high-pressure buffer (4) is connected to the gas inlet of the helium mass spectrometer leak detector (5).

2. The method for establishing a standard curve of helium content in neon gas according to claim 1, characterized in that, the concentration of helium in the helium standard gas in neon is 50 - 1000 ppm.

3. The method for establishing a standard curve of helium content in neon gas according to claim 1, characterized in that, the series of helium standard gases with different concentrations further includes the neon gas to be measured.

4. The method for establishing a standard curve of helium content in neon gas according to claim 1, characterized in that, the linear range of the standard curve of the response value and the increased concentration of helium is 0.1 - 100 ppm.

5. The method for establishing a standard curve of helium content in neon gas according to claim 1, characterized in that, it further includes a first pressure reducer (6) arranged between the neon gas cylinder to be measured (1) and the gas diluter (3); it further includes a second pressure reducer (7) arranged between the helium standard gas cylinder in neon (2) and the gas diluter (3).

6. The method for establishing a standard curve of helium content in neon gas according to claim 1, characterized in that, it further includes a vacuum pump (9), and the intake port of the vacuum pump (9) is connected to the evacuation port of the high-pressure buffer (4).

7. The method for establishing a standard curve of helium content in neon gas according to claim 1, characterized in that, the helium mass spectrometer leak detector (5) is a helium vacuum mass spectrometer leak detector.

8. A method for detecting the helium content in neon gas, characterized in that, it includes the following steps: Use a helium mass spectrometer leak detector to detect the neon gas to be measured to obtain the response value of the neon gas to be measured; Substitute the response value of the neon gas to be measured into the standard curve of the response value and the increased concentration of helium according to any one of claims 1 - 7 to obtain the content of helium in the neon gas to be measured.

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