Semi-conductor laser absorption spectrum gas analyzing method

A technology of laser absorption spectroscopy and gas analysis, which is applied in the measurement of color/spectral characteristics, etc., can solve the limitation of the application field of semiconductor laser absorption spectroscopy gas analysis system, the miniaturization and portability of difficult gas analysis systems, the working current and power consumption of TEC Large and other problems, to achieve the effect of easy intrinsically safe explosion-proof and explosion-proof, portability, simple control and drive circuits

Active Publication Date: 2007-08-15
FOCUSED PHOTONICS
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  • Description
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Problems solved by technology

The coefficient of performance corresponding to the working point is only 35%. It can be seen from the above formula that the total heat dissipation power is 19W. It can be seen that an additional 14W of circuit energy is required to achieve a cooling power of 5W.
[0015] Although the working temperature of the semiconductor laser can be controlled more accurately by using a semiconductor thermoelectric cooler, this solution has the following disadvantages: 1) TEC and specially designed control and drive circuits are required, and the cost is relatively high; 2) the operating current and power of the TEC Large power consumption, low cooling efficiency, short working time when using self-contained power supply, and the large heat generated at the same time increases the complexity and difficulty of thermal design, making it difficult to realize the miniaturization and portability of the gas analysis system; 3) Many applications require the analysis system to have an explosion-proof function. The large operating current makes it impossible or difficult to realize the intrinsically safe explosion-proof design. In addition, the TEC and control and drive circuits lead to a larger volume, which will also increase the complexity of the explosion-proof design
The above shortcomings limit the application field of semiconductor laser absorption spectroscopy gas analysis system using TEC

Method used

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  • Semi-conductor laser absorption spectrum gas analyzing method
  • Semi-conductor laser absorption spectrum gas analyzing method
  • Semi-conductor laser absorption spectrum gas analyzing method

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Embodiment 1

[0043] As shown in FIG. 3 , a semiconductor laser absorption spectrum methane concentration analysis system includes a light emitting unit, a light receiving unit 11 and an analysis unit 12 . The analysis system adopts laser frequency scanning absorption spectroscopy analysis technology.

[0044] The light emitting unit includes a semiconductor laser 1 , a laser base 2 , thermistors 3 and 5 , a current source 9 , a driving circuit 8 , a control device 7 , a heating block 4 and its driving circuit 6 . The semiconductor laser 1 is installed on the laser seat 2, and the thermistor 3 is installed on the laser seat 2 close to the position of the semiconductor laser 1 to monitor the working temperature of the semiconductor laser 1, and the signal of the thermistor 3 is sent to the control device 7, and the control device 7. Control the operating current and temperature of the semiconductor laser 1 after processing. The control device 7 judges whether the laser works at a specified ...

Embodiment 2

[0092] A semiconductor laser absorption spectrum gas analysis method is applied to the flow velocity measurement of methane in pipelines. As shown in Figure 8, the difference between the flow rate measurement system and the methane concentration analysis system in Embodiment 1 is that the light emitted by the semiconductor laser 1 is injected into the measured pipeline 13 through the lens 14, and the clamp between the laser beam and the measured gas flow direction The angle is α=45°, and the laser beam is received by the light receiving unit 11 after passing through the lens 15 . The specific flow rate analysis method includes the following steps:

[0093] A. the specific process is the same as step a in Example 1;

[0094] b. the specific process is the same as step b in Example 1;

[0095] c. The working environment temperature of the semiconductor laser 1 is measured to be 35° C., which is located in the temperature range without absorption lines (30.8° C., 41.6° C.). At ...

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Abstract

This invention discloses one semi-conductor laser absorptive spectrum gas analysis method, which comprises the following steps: a, determining semi-conductor laser work temperature range and current range; b, dividing out at least two work temperature areas and at least one without absorptive area to make any one work temperature relating to at least one absorptive spectrum; c, testing the semi-conductor laser work temperature for T and accordingly determining test gas spectrum; d, according to semiconductor laser work temperature and central frequency and determining and adjusting work current; e, semiconductor laser sends light through tested gas for analysis of spectrum to get gas detector parameters for display.

Description

technical field [0001] The invention relates to a method for analyzing gas parameters, more specifically, to a method for analyzing gas parameters by using semiconductor laser gas absorption spectrum. Background technique [0002] Semiconductor laser absorption spectroscopy gas analysis technology is a widely used gas analysis technology. This technology usually uses a single-mode semiconductor laser. When the beam emitted by the single-mode semiconductor laser has the same frequency as the central frequency of an absorption line of the gas to be measured, the absorption line of the gas to be measured will affect the measurement beam. The absorption of energy results in an attenuation of the measured light intensity. The light intensity attenuation of the semiconductor laser passing through the measured gas can be accurately expressed by the Beer-Lambert relationship: [0003] I v = I v，0 T(v)=I v，0 exp[-S(T)g(v-v 0 )PXL] [0004] I v，0 and I v Respectively represen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/39
Inventor 王健顾海涛刘立鹏
Owner FOCUSED PHOTONICS
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