Semi-conductor laser absorption spectrum gas analyzing method

A technology of laser absorption spectroscopy and analysis method, which is applied in the field of gas parameter analysis using semiconductor laser measurement gas absorption spectroscopy, can solve the problems of miniaturization and portability, high power consumption, inability of difficult gas analysis systems, and achieves miniaturization and Portability, low operating current and power consumption, and the effect of expanding application fields

Active Publication Date: 2007-08-01
FOCUSED PHOTONICS
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Problems solved by technology

[0009] 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 needs to be used and special control and drive circuits are designed, and the cost is relatively high; 2) the working current and power of TEC The power consumption is large, especially when cooling, and the working time is short when using self-contained power supply. At the same time, the large heat generated increases the complexity and difficulty of thermal design, making it difficult to realize the miniaturization of the gas analysis system. 3) Many applications require the analysis system to have an explosion-proof function, and the large operating current makes it impossible or difficult to realize the intrinsically safe explosion-proof design. In addition, the TEC and the drive circuit lead to a larger volume, which will also increase the explosion-proof design. complexity of
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

Examples

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Embodiment 1

[0037] As shown in FIG. 2 , a semiconductor laser oxygen concentration analysis system includes a light emitting unit, a light receiving unit 7 (a sensor is used in this embodiment) and an analysis unit 9 . The analysis system uses frequency sweep analysis technology.

[0038] The light emitting unit includes a semiconductor laser 1 , a laser base 2 , a thermistor 3 , a current source 4 , a driving circuit 5 and a control device 6 . The semiconductor laser 1 is installed on the laser seat 2, and the thermistor 3 is installed on the laser seat 2 near 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 6, and the control device 6. Control the operating current of the semiconductor laser 1 after processing. The working current of the semiconductor laser 1 is provided by the current source 4 , and the driving circuit 5 of the current source 4 is composed of a DC...

Embodiment 2

[0084] A semiconductor laser absorption spectrum gas analysis method is applied to the flow rate measurement of oxygen in pipelines. As shown in Figure 6, the difference between the flow velocity measurement system and the oxygen concentration analysis system in Embodiment 1 is that the light emitted by the semiconductor laser 1 enters the measured pipeline 10 through the lens 11, and the clamp between the laser beam and the measured gas flow direction The angle is α=45°, and the laser beam passes through the lens 12 and is received by the sensor 7 . The specific flow rate analysis method includes the following steps:

[0085] A. The specific method is the same as step a in Example 1;

[0086] B. The specific method is the same as step b in Example 1;

[0087] c. It is measured that the operating temperature of semiconductor laser 1 is 35°C, which is located in the operating temperature range from 32.5°C to 37.5°C. The absorption line corresponding to this operating temperat...

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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 current range; b, dividing the range into at least two work temperature area to make responding to at least one absorptive spectrum line; c, testing semi-conductor laser work temperature range; d, according to the work temperature and step c determining and adjusting semi-conductor laser work current; e, semi-conductor laser sends out light through tested gas to analysis the light signal to get tested gas 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 lasers to measure gas absorption spectra. 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 Respectivel...

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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