Related wheel leakage rate measuring method based on Fourier infrared spectrum technology

Abstract

The invention discloses a correlation wheel leak rate measuring method based on Fourier infrared spectroscopy, comprising the following steps: acquiring gas concentration C0 before aging of a correlation wheel; carrying out high-temperature aging treatment on the related wheels; acquiring the gas concentration C after the aging of the related round, and simultaneously acquiring the gas concentration difference value delta C before and after the aging of the related round; acquiring a pressure change value delta P before and after aging of a related round; and obtaining the leak rate Q after the aging of the related rounds. The leak rate of the related wheel is measured by using the spectrum method, other tracer gases are not needed, the structure of the related wheel is not damaged, the result is quantitative and accurate, and the operation is convenient.

Description

Technical Field

[0001] The invention relates to a gas optical detection technology, and in particular to a correlation wheel leakage rate measurement method based on Fourier infrared spectroscopy technology. Background Art

[0002] Non-dispersive infrared absorption technology (NDIR) is a method of material detection based on the principle that molecules absorb infrared light of a specific wavelength. It is particularly used to measure the concentration of carbon oxides (such as carbon monoxide and carbon dioxide). This method is widely used in the fields of environmental air, water quality and soil testing. The gas filter correlation (GFC) technology commonly used in NDIR has a key component, the GFC correlation wheel, which is generally composed of a measuring cell (filled with non-absorbing gas, such as N 2 ) and a reference cell (filled with high-concentration measuring gas, such as CO with a concentration of more than 60%). The stability of the gas concentration in the gas cell is one of the key factors to ensure that the measurement results do not drift. However, in fact, the relevant wheel still cannot avoid leakage during operation, resulting in a large long-term drift of the measured gas concentration, affecting the measurement accuracy. Therefore, it is very necessary to measure the leakage rate of the relevant wheel. The current methods for measuring the leakage rate mainly include differential pressure detection, such as helium mass spectrometer leak detector. The pressurization will far exceed the normal use state of the relevant wheel, and tracer gas needs to be added, which is different from the conventionally used N 2 There are differences, it is only applicable to test samples, it cannot be used in standard related wheels, and the measured leak rate may not meet the requirements of the service life of the related wheels. Summary of the invention

[0003] In order to solve the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for measuring the correlation wheel leakage rate based on Fourier transform infrared spectroscopy technology.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for measuring the correlation wheel leakage rate based on Fourier infrared spectroscopy technology, comprising the following steps:

[0005] Get the gas concentration C before the relevant wheel aging 0 ;

[0006] Carry out high temperature aging treatment on relevant wheels;

[0007] Obtain the gas concentration C of the relevant wheel after aging, and simultaneously obtain the gas concentration difference ΔC before and after aging of the relevant wheel;

[0008] Obtain the pressure change value ΔP of the relevant wheel before and after aging;

[0009] Obtain the leakage rate Q of the relevant wheel after aging;

[0010] Among them, the gas concentration difference ΔC before and after aging of the relevant wheel is obtained by the following formula:

[0011] ΔC = |C - C 0 |;

[0012] The pressure change value ΔP before and after aging of the relevant wheel is obtained by the following formula,

[0013] ΔP = ΔC * R * T,

[0014] where R is the Boltzmann constant and T is the gas temperature;

[0015] The leak rate Q is obtained by the following formula,

[0016] Q = ΔP * V / ΔT,

[0017] where V is the volume of the relevant wheel gas chamber and ΔT is the time change value.

[0018] Optionally, before obtaining the gas concentration before aging of the relevant wheel, first perform background calibration on the relevant wheel, and then perform calibration gas calibration on the relevant wheel to obtain the absorbance spectrum of the calibration gas.

[0019] Optionally, when obtaining the gas concentration before aging of the relevant wheel, according to the formula

[0020] A = log(I 0 / I)

[0021] obtain the absorbance spectrum of the gas in the gas chamber, and then perform non - linear least - squares calculation on the absorbance spectrum of the gas in the gas chamber and the absorbance spectrum of the calibration gas to obtain the gas concentration C 0 ,

[0022] where I 0 is the transmission spectrum of the measurement cell of the relevant wheel, and I is the transmission spectrum of the reference cell of the relevant wheel.

[0023] Adopting the above - mentioned technical solution, the present invention measures the leak rate of the relevant wheel by spectroscopy, does not require other tracer gases, does not damage the structure of the relevant wheel itself, the result is quantitatively accurate, and the operation is convenient. Specific Embodiments

[0024] The following further elaborates on the present application in conjunction with embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than limiting the invention.

[0025] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The following will elaborate on the present application in conjunction with embodiments.

[0026] The present invention proposes a method for measuring the leakage rate of a related wheel, which is based on a Fourier infrared spectroscopy analysis system to measure the concentration change of the related wheel before and after aging, and then calculate the leakage rate of the related wheel. Specifically, the Fourier infrared spectroscopy analysis system obtains the measured spectral data of the related wheel and processes the data to obtain the leakage rate of the related wheel.

[0027] Before measuring the leakage rate of the correlation wheel, the correlation wheel needs to be fixed, so the correlation wheel can be installed in the Fourier infrared spectroscopy analysis system so that the infrared beam is detected by the detector after passing through the correlation wheel, thereby obtaining the transmission spectrum data.

[0028] After the relevant wheel is installed, the leakage rate of the relevant wheel can be measured. The steps are as follows:

[0029] S1. Obtain the gas concentration C before the relevant wheel aging 0 .

[0030] The gas concentration C before obtaining the relevant wheel aging 0 Previously, it was necessary to perform background calibration and calibration of the relevant wheel to obtain the absorbance spectrum data of the calibration gas.

[0031] When obtaining the gas concentration before the relevant wheel aging, according to the formula

[0032] A=log(I 0 / I)

[0033] Obtain the absorbance spectrum of the gas in the gas chamber, and then perform nonlinear least squares calculation on the absorbance spectrum of the gas in the gas chamber and the absorbance spectrum of the standard gas to obtain the concentration C of the gas in the gas chamber. 0 .

[0034] Among them, I 0 is the transmission spectrum of the measuring cell of the relevant wheel, and I is the transmission spectrum of the reference cell of the relevant wheel. The measuring cell of the relevant wheel is filled with a non-absorbing gas, such as N 2 , in the reference cell of the relevant wheel, there is a high concentration measurement gas, such as CO with a concentration of more than 60%.

[0035] S2. Perform high temperature aging treatment on the relevant wheels.

[0036] S3. Obtain the gas concentration C of the relevant wheel after aging, and simultaneously obtain the gas concentration difference ΔC before and after aging of the relevant wheel.

[0037] When obtaining the gas concentration of the relevant wheel after aging, the method of step S1 is followed to finally obtain the gas concentration C of the relevant wheel after aging. The Fourier infrared spectroscopy analysis system obtains data C and C 0 After that, the concentration difference ΔC between the two is calculated, and the calculation formula is:

[0038] ΔC = |C - C 0 |.

[0039] S4. Obtain the pressure change value ΔP before and after aging of the relevant wheel.

[0040] The pressure change value ΔP before and after aging of the relevant wheel is obtained through the following formula,

[0041] ΔP = ΔC * R * T,

[0042] where R is the Boltzmann constant and T is the gas temperature;

[0043] S5. Obtain the leakage rate Q after aging of the relevant wheel.

[0044] The leakage rate Q is obtained through the following formula,

[0045] Q = ΔP * V / ΔT,

[0046] where V is the volume of the air chamber of the relevant wheel and ΔT is the time change value.

[0047] S6. After obtaining the leakage rate Q, feedback it to the Fourier transform infrared analysis system, and the Fourier transform infrared analysis system compensates the analysis results of the sample gas.

[0048] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in the present application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0049] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

[0050] Except for the technical features described in the specification, the remaining technical features are known technologies to those skilled in the art. In order to highlight the innovative features of the present invention, the remaining technical features will not be described here in detail.

Claims

1. A method for measuring the leakage rate of a related wheel based on Fourier transform infrared spectroscopy technology, characterized in that: It includes the following steps: Obtain the gas concentration C0 before aging of the relevant wheel; Conduct high-temperature aging treatment on the relevant wheel; Obtain the gas concentration C after aging of the relevant wheel, and simultaneously obtain the gas concentration difference ΔC before and after aging of the relevant wheel; Obtain the pressure change value ΔP before and after aging of the relevant wheel; Obtain the leak rate Q after aging of the relevant wheel; Among them, the gas concentration difference ΔC before and after aging of the relevant wheel is obtained by the following formula: ΔC = 丨C - C0丨; The pressure change value ΔP before and after aging of the relevant wheel is obtained by the following formula: ΔP = ΔC * R * T, In the formula, R is the Boltzmann constant, and T is the gas temperature; The leak rate Q is obtained by the following formula: Q = ΔP * V / ΔT, In the formula, V is the volume of the gas chamber of the relevant wheel, and ΔT is the time change value.

2. The method for measuring the correlation wheel leakage rate based on Fourier transform infrared spectroscopy technology according to claim 1 is characterized in that: Before obtaining the gas concentration before aging of the relevant wheel, first conduct background calibration on the relevant wheel, and then conduct standard gas calibration on the relevant wheel to obtain the absorbance spectrum of the standard gas.

3. The method for measuring the correlation wheel leakage rate based on Fourier transform infrared spectroscopy technology according to claim 2 is characterized in that: When obtaining the gas concentration before aging of the relevant wheel, according to the formula A = log (I0 / I) Obtain the absorbance spectrum of the gas in the gas chamber, and then perform nonlinear least squares calculation on the absorbance spectrum of the gas in the gas chamber and the absorbance spectrum of the standard gas to obtain the gas concentration C0 in the gas chamber. Among them, I0 is the transmission spectrum of the measurement cell of the relevant wheel, and I is the transmission spectrum of the reference cell of the relevant wheel.