Inclined incidence type particulate matter concentration detection device
Through the tilt incident design, the combination of collimating lens and receiving lens is used to solve the problem of multiple reflections of incident light and long light paths in the light scattering method, and the signal quality and optical path collimation of particulate concentration measurement are improved.
Patent Information
- Application Number
- CN202510019377.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2025-03-04
AI Technical Summary
In the measurement of particle concentration, the existing light scattering method results in poor signal-to-noise ratio due to multiple reflections and scattering of incident light, and the long light path leads to difficulty in collimation of the optical path and poor back-blowing cleaning effect.
The tilt incident design is adopted. After the light emitted by the laser is collimated into a parallel beam through the collimating lens, it is tilted on the particle sample. The scattered signal generated is converged onto the photodetector through the receiving lens, avoiding the problem of multiple reflections of incident light and long light paths.
It effectively solves the scattered signal interference caused by multiple reflections of incident light in the reverse direction, improves the signal-to-noise ratio, and avoids the problems of difficulty in optical path collimation and low backblowing cleaning efficiency.
Smart Images
Figure CN119555563A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of particle measurement, and in particular to an oblique-incidence particle concentration detection device. Background Art
[0002] At present, the main methods for measuring the concentration of environmental pollution particles are filter membrane weighing method, micro-oscillating balance method, β-ray absorption method and light scattering method. Among them, light scattering method is a relatively mature and easy-to-use detection method. It has the advantages of high sensitivity, fast measurement speed and good real-time performance, and is used for online detection of particles in the atmospheric environment and industrial solid pollution sources.
[0003] The light scattering particle concentration measurement device continuously collects particle samples into the sample pool, and the sample pool usually adopts a round or square glass tube. Generally, the optical axis of the incident light is placed perpendicular to the axis of the glass tube. Therefore, the glass tube wall placed perpendicular to the optical axis of the incident light will reflect the incident light multiple times, and the reflected light repeatedly irradiates the sample to cause complex scattering, resulting in non-unique angular distribution of received scattered light and poor signal-to-noise ratio; or the incident light axis is placed coaxially with the axis of the glass tube, but a light trap needs to be set on the opposite side, otherwise the measurement will be affected by multiple reflections and scattering. At the same time, due to the long optical path, it will cause problems such as difficulty in optical path alignment and poor backblowing cleaning effect. Summary of the invention
[0004] The present invention provides an oblique-incidence particle concentration detection device to solve the problem of multiple scattering or too long light path caused by multiple irradiation of incident light on a particle sample measurement area.
[0005] The present invention specifically adopts the following technical means:
[0006] An oblique-incidence particle concentration detection device comprises a laser 1, a collimating lens 2, a sample pool 3, a particle sample 4, a receiving lens 5, and a photoelectric detector 6.
[0007] The measuring light is emitted by the laser 1, and after being collimated into a parallel beam by the collimating lens 2, it is incident on the sample pool 3, and irradiates the particle sample 4 to cause scattering. The generated scattered signal is focused on the photodetector 6 through the receiving lens 5, and the particle concentration information is obtained through signal collection and processing.
[0008] Furthermore, the angle θ1 between the meridian plane of the laser 1 and the optical axis of the receiving lens 5 is 45° to 60°.
[0009] Furthermore, the angle θ2 between the optical axis of the laser 1 and the cross section of the sample cell 3 is 30° to 45°.
[0010] Furthermore, the collimating lens 2 is coaxial with the laser 1 and is used to collimate the light emitted by the laser 1 into a parallel light beam.
[0011] Furthermore, the optical axis of the receiving lens 5 is placed perpendicular to the axis of the sample pool 3, and the angle θ3 between the optical axis of the laser 1 and the projection of the optical axis of the receiving lens 5 on the cross section of the sample pool 3 is 35° to 45°.
[0012] Furthermore, the signal collected by the photoelectric detector 6 is collected and processed by a computer to obtain particle concentration information.
[0013] Advantages and positive effects of the present invention:
[0014] When the incident light is collimated as parallel light and irradiates the particle sample 4, the incident light inclined to the axis of the sample cell is reflected multiple times on the wall of the sample cell instead of being reflected in the opposite direction, and finally emitted from the other end of the sample cell 3, thus solving the problem of multiple scattering of the particle sample 4 caused by multiple reflections of the incident light in the opposite direction and interference with the reception of the scattered signal. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a schematic structural diagram of an oblique-incidence particle concentration detection device provided by the present invention, wherein 1 is a laser, 2 is a collimating lens, 3 is a sample pool, 4 is a particle sample, 5 is a receiving lens, and 6 is a photoelectric detector.
[0016] Figure 2 This is a top view of an oblique-incidence particle concentration detection device provided by the present invention, wherein 1 is a laser, 2 is a collimating lens, 3 is a sample pool, 4 is a particle sample, 5 is a receiving lens, and 6 is a photoelectric detector. DETAILED DESCRIPTION
[0017] The following specific implementations are only some examples for describing the present invention in detail and should not be construed as limiting the present invention. The structure and principle of the present invention are described in detail below in conjunction with the accompanying drawings:
[0018] An oblique-incidence particle concentration detection device, such as Figure 1 As shown, it includes a laser 1, a collimating lens 2, a sample pool 3, a particle sample 4, a receiving lens 5, and a photodetector 6. The laser 1 is coaxial with the collimating lens 2. The light emitted by the laser 1 is collimated into parallel light by the collimating lens 2 and then irradiated on the particle sample 4. The angle θ1 between the meridian plane of the laser 1 and the optical axis of the receiving lens 5 is 45° to 60°, and the angle θ2 between the optical axis of the laser 1 and the cross section of the sample pool 3 is selected to be an angle between 30° and 45° according to the particle size. The receiving lens 5 is coaxial with the photodetector 6 and is placed perpendicular to the axis of the sample pool 3. At this time, there is an angle θ3 between the optical axis of the laser 1 and the projection of the optical axis of the receiving lens 5 on the cross section of the sample pool 3. θ3 can be calculated based on θ1 and θ2, and θ3 is 35° to 45°.
[0019] In the embodiment, the angle θ1 between the meridian plane of the laser 1 and the optical axis of the receiving lens 5 is 45°, the angle θ2 between the optical axis of the laser 1 and the cross section of the sample pool 3 is 30°, and the angle θ3 between the optical axis of the laser 1 and the projection of the optical axis of the receiving lens 5 on the cross section of the sample pool 3 is 35°.
[0020] Specifically, the sample flue gas is sent into the sample pool 3 from the air inlet and flows out from the air outlet. The light emitted by the laser 1 is collimated into a parallel beam by the collimating lens 2 and then incident on the sample pool 3, and irradiates the particle sample 4 to cause scattering. The receiving lens 5 converges the scattered signal onto the photodetector 6, which is coaxial with the receiving lens 5. The scattered signal collected by the photodetector 6 is obtained through signal collection and processing to obtain the actual particle concentration information.
[0021] When the device provided by the present invention is used to detect the concentration of particulate matter, the light emitted by the laser 1 is collimated into a parallel beam by a collimating lens, and then irradiated obliquely on the particle sample 4 to cause scattering. Compared with the prior art, during the measurement process, the oblique incident light will be reflected multiple times on the sample pool wall and emitted from the sample pool 3, but will not be reflected in the reverse direction of the original light, and will not be repeatedly irradiated on the particle sample 4 to cause scattering superposition. Compared with the method in which the incident light is incident perpendicular to the sample pool wall, the problem of multiple reflections of the incident light in the reverse direction in the sample pool 3 interfering with the collection of the scattering signal is solved; at the same time, the problem of difficulty in light path alignment and low backwashing cleaning efficiency due to the long light path is avoided.
Claims
1. An oblique-incidence particle concentration detection device, characterized in that: The invention comprises a laser (1), a collimating lens (2), a sample pool (3), a particle sample (4), a receiving lens (5), and a photoelectric detector (6). The light emitted by the laser (1) is collimated into parallel light by the collimating lens (2) and then irradiated onto the particle sample (4) to cause scattering, wherein the angle between the meridian plane of the laser (1) and the optical axis of the receiving lens (5) is θ1, and the angle between the optical axis of the laser (1) and the cross section of the sample pool (3) is θ2. The scattered light signal generated by the particle is converged by the receiving lens (5) onto the photoelectric detector (6), and the particle concentration information is obtained through signal collection and processing. The optical axis of the receiving lens (5) is placed perpendicular to the axis of the sample pool (3), and the angle between the optical axis of the receiving lens (5) and the projection of the optical axis of the laser (1) on the cross section of the sample pool (3) is θ3.
2. According to the oblique-incidence particle concentration detection device of claim 1, the angle θ1 between the optical axis of the receiving lens (5) and the meridian plane of the laser (1) is 45° to 60°.
3. According to the oblique-incidence particle concentration detection device of claim 1, the angle θ2 between the optical axis of the laser (1) and the sample pool (3) is 30° to 45°.
4. According to the oblique-incidence particle concentration detection device of claim 1, the angle θ3 between the optical axis of the receiving lens (5) and the projection of the optical axis of the laser (1) on the cross section of the sample pool (3) is 35° to 45°.