Dust particle counter detection cavity

Abstract

The utility model discloses a dust particle counter detection cavity, which comprises a reflecting lens and an absorption sleeve, the reflecting lens and the absorption sleeve define a sealed detection cavity, an air inlet nozzle, an air outlet nozzle, a laser and a light trap are respectively arranged on a cross axis of the detection cavity, the air inlet nozzle and the air outlet nozzle are arranged on the same axis, and the laser is arranged on the light trap. The laser and the light trap are arranged on the same axis, and a photoelectric detector is arranged at the bottom of the absorption sleeve; the stray light is absorbed and collected by matching the reflecting lens and the absorbing sleeve with the grating and the light trap, so that the collection efficiency of the stray light in the detection cavity can be effectively improved, the stray light in the detection cavity is eliminated and inhibited, the detection error is reduced, the particle counting detection precision is improved, and the problem of optical system detection error caused by the stray light is solved; the whole structure is simple, the preparation cost is low, and the detection operation is convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of particle counters, in particular to a detection cavity of a dust particle counter. Background Technique

[0002] A dust particle counter is an instrument used to measure the number of dust particles per unit volume and the particle size distribution in a clean environment. When particles in the air are irradiated by light, light scattering will occur. This phenomenon is called light scattering. Light scattering is related to factors such as the particle size, the wavelength of the light wave, the refractive index of the particle, and the light absorption characteristics of the particle. However, regarding the intensity of the scattered light and the particle size, there is a basic law, that is, the intensity of the scattered light of the particle increases with the increase of the surface area of the particle. Thus, as long as the intensity of the scattered light is measured, the particle size can be inferred, which is the basic principle of a light scattering type particle counter.

[0003] When a particle counter counts dust particles using light scattering, stray light will appear. Stray light is the general term for all non-normal propagation light in an optical system, including light leakage generated by the optical system, residual reflections on the surface of optical elements, and residual reflections on non-optical surfaces, etc. As people's requirements for the accuracy of optical instruments are getting higher and higher, the influence of stray light is becoming more and more obvious. Several common methods used to reduce stray light in the system include using a diaphragm control, a light shield, and an absorbing and extinction coating. Currently, the methods used to reduce stray light in particle counters are relatively single, the inhibitory effect on stray light is limited, the detection error is large, and the detection accuracy is affected. For this reason, this application proposes a detection cavity of a dust particle counter to solve the above problems. Content of the Utility Model

[0004] The technical problem to be solved by the utility model is: to provide a detection cavity of a dust particle counter that can eliminate and suppress stray light and improve the detection accuracy.

[0005] To solve the above technical problem, the utility model includes a reflecting lens and an absorption sleeve. The reflecting lens and the absorption sleeve enclose a sealed detection cavity. An air inlet nozzle, an air outlet nozzle, a laser, and a light trap are respectively installed on the cross axis of the detection cavity. The air inlet nozzle and the air outlet nozzle are on the same axis, and the laser and the light trap are on the same axis. A photodetector is provided at the bottom of the absorption sleeve.

[0006] Preferably, it further includes a first fixed platform and a second fixed platform. The reflecting lens is installed on the first fixed platform, the absorption sleeve is installed on the second fixed platform, and the laser and the light trap are installed at both ends of the junction of the first fixed platform and the second fixed platform.

[0007] Preferably, the reflecting lens is a plano-concave spherical lens, and the concave spherical surface of the reflecting lens faces the detection cavity.

[0008] Preferably, the reflecting lens is made of frosted glass.

[0009] Preferably, light stray elimination diaphragms are provided on both sides of the top of the absorption sleeve.

[0010] Preferably, the absorption sleeve is frustum-shaped or cylindrical, and the diameter of the upper circular surface of the absorption sleeve is the same as the diameter of the concave spherical surface of the reflecting lens.

[0011] Preferably, the diameter of the lower circular surface of the absorption sleeve is larger than the width of the photodetector.

[0012] Preferably, the absorption sleeve is made of a black light-absorbing material.

[0013] Preferably, absorption and reflection surfaces are provided on both sides of the bottom surface of the absorption sleeve where it is located on both sides of the photodetector.

[0014] Preferably, the absorption and reflection surface is one of a wavy shape, a columnar shape, or a V-shaped.

[0015] The beneficial effects of the present utility model are as follows: through the cooperation of the reflecting lens, the absorption sleeve, the grating, and the light trap, the present utility model absorbs and collects stray light, which can effectively improve the collection efficiency of stray light in the detection cavity, eliminate and suppress the stray light in the detection cavity, reduce the detection error, improve the particle counting detection accuracy, solve the problem of the detection error of the optical system caused by stray light, and has a simple overall structure, low preparation cost, and convenient detection operation. Description of the Drawings

[0016] Figure 1 is a schematic diagram of the overall structure of the present utility model;

[0017] Figure 2 is Figure 1 the schematic diagram of the A-A cross-section in

[0018] Figure 3 is the schematic diagram of the overall structure of the present utility model Figure 2 ;

[0019] Figure 4 is the schematic diagram of the overall structure of the present utility model Figure 3 。

[0020] In the figure: 1, the first fixed platform; 2, the second fixed platform; 3, the reflecting lens; 4, the absorption sleeve; 5, the detection cavity; 6, the intake nozzle; 7, the exhaust nozzle; 8, the laser; 9, the light trap; 10, the photodetector; 11, the light stray elimination diaphragm; 12, the absorption and reflection surface. Detailed Embodiments

[0021] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. All directional indications (such as up, down, left, right, front, back...) in the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0022] As Figures 1-4 shown, this embodiment provides a detection cavity for a dust particle counter, which includes a first fixed platform 1, a second fixed platform 2, a reflecting lens 3, and an absorption sleeve 4. The reflecting lens 3 is installed on the first fixed platform 1, the absorption sleeve 4 is installed on the second fixed platform 2, the reflecting lens 3 and the absorption sleeve 4 enclose a sealed detection cavity 5. An air inlet nozzle 6, an air outlet nozzle 7, a laser 8, and an optical trap 9 are respectively installed on the cross axis of the detection cavity 5. The laser 8 and the optical trap 9 are installed at both ends of the junction of the first fixed platform 1 and the second fixed platform 2. The air inlet nozzle 6 and the air outlet nozzle 7 are on the same axis, so that the air enters and exits linearly. The laser 8 and the optical trap 9 are on the same axis. The optical trap 9 is used to absorb light and reduce the reflection of stray light. A photodetector 10 is provided at the bottom of the absorption sleeve 4.

[0023] The reflecting lens 3 is a plano-concave spherical lens, and the concave spherical surface of the reflecting lens 3 faces the detection cavity 5. The reflecting lens 3 is made of frosted glass. The reflecting lens 3 is used to reflect and converge light, and the reflecting lens 3 reflects the light to the photodetector 10.

[0024] Two stray light elimination diaphragms 11 are provided on both sides of the top of the absorption sleeve 4, and the stray light elimination diaphragms 11 can block part of the stray light.

[0025] The shape of the absorption sleeve 4 is a frustum or a cylinder, and the diameter of the upper circular surface of the absorption sleeve 4 is the same as the diameter of the concave spherical surface of the reflecting lens 3, so that the absorption sleeve 4 and the reflecting lens 3 can seal the detection cavity 5, and the diameter of the lower circular surface of the absorption sleeve 4 is larger than the width of the photodetector 10, which is convenient for arranging an absorbent structure outside the photodetector 10 at the bottom of the absorption sleeve 4. The absorption sleeve 4 is made of a black light-absorbing material, such as black ceramic material, black plastic, or black metal material, or a black material can also be coated on the inner surface of the absorption sleeve 4 to achieve the purpose of light absorption, so that the absorption sleeve 4 can absorb the reflected stray light.

[0026] Absorption reflecting surfaces 12 are provided on both sides of the bottom surface of the absorption sleeve 4 where the photodetector 10 is located. The absorption reflecting surfaces 12 are one of a wavy shape, a columnar shape, or a V-shaped shape, and are used to reflect and absorb stray light multiple times to improve the collection efficiency of stray light.

[0027] The working principle of the present utility model is as follows: When particles enter the detection cavity 5 through the intake nozzle 6 and are discharged from the outlet nozzle 7, most of the scattered light generated under the irradiation of the laser produced by the laser 8 reaches the photodetector 10 under the converging action of the reflecting lens 3. The photodetector 10 converts the light signal into a current-voltage signal, and the particle number is calculated based on the current-voltage signal. Part of the stray light enters the optical trap 9 under the converging action of the reflecting lens 3 and is absorbed. Part of the stray light is blocked by the stray light elimination diaphragm 11. There is also part of the stray light that is continuously reflected and attenuated between the absorption and reflection surfaces 12 under the converging and reflecting action of the reflecting lens 3 and is finally absorbed by the absorption and reflection surface 12. It can effectively improve the collection efficiency of the stray light in the detection cavity 5, eliminate and suppress the stray light in the detection cavity 5, reduce the detection error, improve the particle counting detection accuracy, solve the problem of the detection error of the optical system caused by the stray light, and the overall structure is simple, the preparation cost is low, and the detection operation is convenient.

[0028] Although the embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A detection cavity of a dust particle counter, characterized in that, It includes a reflecting lens and an absorption sleeve. The reflecting lens and the absorption sleeve enclose a sealed detection cavity. An air inlet nozzle, an air outlet nozzle, a laser and an optical trap are respectively installed on the cross axis of the detection cavity. The air inlet nozzle and the air outlet nozzle are on the same axis, and the laser and the optical trap are on the same axis. A photodetector is provided at the bottom of the absorption sleeve.

2. The dust particle counter detection cavity according to claim 1, wherein It further includes a first fixed platform and a second fixed platform. The reflecting lens is installed on the first fixed platform, the absorption sleeve is installed on the second fixed platform, and the laser and the optical trap are installed at both ends of the junction of the first fixed platform and the second fixed platform.

3. A dust particle counter detection cavity according to claim 1, wherein, The reflecting lens is a plano-concave spherical lens, and the concave spherical surface of the reflecting lens faces the detection cavity.

4. A dust particle counter detection cavity according to claim 3, wherein, The reflecting lens is made of frosted glass.

5. A dust particle counter detection cavity according to claim 1, wherein, Light shielding diaphragms are provided on both sides of the top of the absorption sleeve.

6. The detection cavity of a dust particle counter according to claim 1, wherein The shape of the absorption sleeve is a frustum of a cone or a cylinder, and the diameter of the upper circular surface of the absorption sleeve is the same as the diameter of the concave spherical surface of the reflecting lens.

7. A dust particle counter detection cavity according to claim 6, characterized in that, The diameter of the lower circular surface of the absorption sleeve is larger than the width of the photodetector.

8. A dust particle counter detection cavity according to claim 1, characterized in that, The absorption sleeve is made of a black light-absorbing material.

9. A dust particle counter detection cavity according to any one of claims 1-8, characterized in that Absorption and reflection surfaces are provided on both sides of the bottom surface of the absorption sleeve where it is located at the photodetector.

10. A dust particle counter detection cavity according to claim 9, characterized in that, The absorption and reflection surface is one of a wavy shape, a columnar shape or a V-shaped shape.

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