Side wall air inlet/outlet infrared air sensor

[0032] figure 1 It shows the internal structure of the sensitive head of the infrared gas sensor with side wall inlet/outlet provided by the embodiment of the present invention. The dust cover 1 is made of 60-80 mesh stainless steel powder and sintered with a stainless steel shell. The outer diameter is 40mm, the inner diameter is 34.5mm, and the height is 18mm cylinder; the dust cover 1 is embedded with a cylinder with a diameter of 34mm and a height of 16mm. -Shaped brass cavity 2; the right end of the cavity 2 is provided with a first through hole 10 with a diameter of 5mm at the right end, a condenser 7 is arranged at the rear end of the first through hole 10 at the right end, and an infrared light source 6 is installed in the condenser 7, and a first through hole at the right end At least two vent holes 14 with a diameter of 1-3mm are opened on the side wall of the cavity 2; a second through hole 11 with a diameter of 5mm is opened at the front end of the cavity 2, and the second through hole 11 at the front end is 90 degrees from the first through hole 10 at the right end. The right first reflector 3 is placed in the first groove 17 on the intersecting surface, and the bottom surface of the groove 17 forms an angle of 45 degrees with the first through hole 10 at the right end and the second through hole 11 at the front end, respectively. At least two vent holes 15 with a diameter of 1-3mm are opened on the side wall of the second through hole 11 at the front end; the left end of the cavity 2 is opened with a third through hole 12 at the left end with a diameter of 6mm. A through hole 10 is parallel to the second through hole 11 at an angle of 90 degrees. A groove 18 is cut on the intersecting surface to place the left second reflector 4, and the bottom surface of the cut groove 18 is respectively connected to the front end of the second through hole 11 and The third through hole 12 at the left end forms an included angle of 45 degrees, the rear end of the third through hole 12 at the left end is equipped with a thermopile detector 5, and at least two vent holes 16 with a diameter of 1-3 mm are opened on the side wall of the third through hole 12 ; A groove 19 is opened at the bottom of the cavity 2 and a heating resistor 8 is placed. As an embodiment of the present invention, the first through hole 10, the second through hole 11, the third through hole 12, and the inner wall of the condenser 7 are polished to achieve a smoothness of 0.1, and the inner wall is gold-plated to improve the reflectivity of infrared light , And play a role in preventing oxidation and corrosion of copper.

[0033] The thermopile detector used in the present invention is the dual-channel thermopile infrared detector developed by the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences or the TPS2534 series dual-channel thermopile detector 5 produced by PerkinElmer, Germany, with X.Xμm and Y.Yμm two filters, the thermopile output signal corresponding to the X.Xμm wavelength is the measurement signal, and the thermopile output signal corresponding to the Y.Yμm wavelength is the reference signal; the detector is equipped with a thermistor to provide The temperature signal required for sensor temperature compensation. The output of the thermopile detector includes measurement signal, reference signal and temperature signal.

[0034] figure 2 It shows a schematic diagram of the working principle of the infrared gas sensor with air inlet/outlet on the side wall of the present invention. The air carrying flammable and explosive gas waiting to be measured diffuses into and fills the air chamber through the vent holes 14, 15, 16 on the side wall of the sensor. The modulated infrared light emitted by the infrared light source 6 passes through the right first through hole 10 and is reflected by the right first reflector 3, then enters the front second through hole 11, and reaches the left second reflector 4 along the front second through hole 11, and is reflected Then it enters the third through hole 12 at the left end. The infrared light is reflected multiple times, absorbed by the gas to be measured, and selectively absorbed by the filter, and finally reaches the surface of the thermopile chip, the core component of the dual-channel thermopile detector 5, and is The stack senses and absorbs and converts it into electrical signals. The two signals output by the thermopile detector are amplified by the amplifier circuit 9 to obtain a stable signal, which is then collected by the A/D signal acquisition module and sent to the signal processing module. The signal processing module analyzes the two signals with the help of the single-chip microcomputer and the corresponding program After processing, the concentration of the gas to be measured in the air is obtained, which is displayed intuitively by the signal display module.

[0035] The infrared light source 6 used in the infrared gas sensor for gas inlet/outlet from the side wall of the present invention can be, but is not limited to, IRL715 of PerkinElmer.

[0036] The right first reflector 3 and the left second reflector 4 used in the infrared gas sensor with side wall inlet/outlet of the present invention are sputtered on silicon but not limited to sputtering 200 nm gold, and the right first reflector 3 and The size of the left second mirror 4 is the same as the size of the bottom surface of the first cut groove 17 and the second cut groove 18 respectively.

[0037] The infrared gas sensor with gas inlet/outlet on the side wall of the present invention can realize the monitoring of different gases by replacing the thermopile detector encapsulated with absorption wavelength filters with different characteristics. Among them, the center wavelength of the reference filter can be selected but not limited to 3.9μm, 4.0μm, etc.; the characteristic absorption peaks of common gases can be seen but not limited to the following table:

[0038]

[0039] Finally, it should be emphasized that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the embodiments describe the present invention in detail, those skilled in the art can still modify the technical solutions of the present invention. Or partial replacement, any modification or replacement of the scheme that does not depart from the spirit of the technical scheme of the present invention shall be included in the protection scope of the present invention.