Particle counting sensor

Abstract

The utility model discloses a particle counting sensor which comprises a shell and a laser used for emitting light beams, a scattering space is formed in the shell, a light path channel is formed in the shell in the X-th direction, a scattered light collecting and receiving channel is formed in the shell in the Y-th direction, and a gas path channel is formed in the shell in the Z-th direction. The light path channel, the scattered light collecting and receiving channel and the gas path channel all penetrate through the shell, and the light path channel, the scattered light collecting and receiving channel and the gas path channel intersect in the scattering space. According to the utility model, stray light on a light path channel can be reduced, and the extinction effect of a light trap is improved, so that the generated stray light is reduced to the maximum extent.

Description

TECHNICAL FIELD

[0001] The utility model relates to the related technical field of optical detection device, more accurate to say relates to a particle counting sensor. BACKGROUND

[0002] The basic principle of the particle counter is that the scattered light of the detection laser of the optical sensor scattered by the dust particle is received by the photosensitive element and generates a pulse signal, the pulse signal is output and amplified, then digital signal processing is carried out, comparison with the standard particle signal is carried out, and the comparison result is expressed by different parameters. The particles in the air will scatter under the irradiation of light, which is called light scattering. The amount of scattered light scattered by light is related to particle size, light wavelength, particle refractive index and particle absorption characteristics. However, in terms of scattered light intensity and particle size, there is a basic rule that the amount of particle scattering light increases with the increase of the surface area of the particle. In this way, the size of the particle can be inferred by measuring the amount of scattered light. In fact, the scattered light intensity generated by each particle is very weak, which is a very small light pulse. The light pulse needs to be converted into an electric pulse with larger signal amplitude through the amplification of the photoelectric converter, and then further amplified and distinguished by the circuit system, so as to complete the counting work of a large number of electric pulses. At this time, the number of electric pulses corresponds to the number of particles, and the amplitude of the electric pulse corresponds to the size of the particle, which is the basic principle of the light scattering particle counter.

[0003] The particle counter has been committed to maximizing the removal of stray light on the light path formed by the light beam emitted by the laser. Usually, technicians take two approaches, one is to converge and collimate the light beam to reduce the stray light that escapes due to the divergence angle, and the other is to absorb the stray light that escapes.

[0004] Therefore, how to maximize the removal of stray light on the light path formed by the light beam emitted by the laser is an important problem that needs to be solved in the industry. UTILITY MODEL CONTENT

[0005] Therefore, the utility model aims to provide a particle counting sensor.

[0006] To achieve the above purpose, the utility model adopts the technical scheme of:

[0007] A particle counting sensor comprises a housing and a laser for emitting a light beam, a scattering space is formed in the housing, a light path channel is formed in the housing along a first X direction, a scattering light collection receiving channel is formed in the housing along a first Y direction, and an air path channel is formed in the housing along a first Z direction, the light path channel, the scattering light collection receiving channel and the air path channel all pass through the housing, and the light path channel, the scattering light collection receiving channel and the air path channel meet in the scattering space;

[0008] The laser is arranged on the light path channel at the end of the housing, a lens assembly and a light trap are arranged along the light beam propagation path in the light path channel, the light beam passes through the lens assembly and the scattering space in sequence and is absorbed by the light trap, an air path assembly for the flow of the air to be measured is arranged on the air path channel, and a scattering light collection assembly is arranged on the scattering light collection receiving channel.

[0009] Holes are formed in the housing in front of and behind the scattering space, the groove body of the hole partially overlaps the light path channel, a plug is arranged at the opening of the hole, the hole communicates with the light path channel and forms a pit on the inner side of the light path channel.

[0010] Further, the hole comprises a first hole and a second hole, the plug comprises a first plug and a second plug, the first hole is sleeved with the first plug at the opening thereof, and the second hole is sleeved with the second plug at the opening thereof.

[0011] Further, the light trap at least partially extends into the second hole, the light trap comprises a third plug sleeved with the light path channel and a third light extinction sheet arranged obliquely at the end of the third plug close to the scattering space.

[0012] The included angle θ1 between the surface of the third light extinction sheet and the end surface of the second plug close to the light path channel is 40°-50°, and the incident angle θ2 of the light on the optical axis of the light beam on the third light extinction sheet is 40°-50°.

[0013] Further, the opening directions of the first hole and the second hole are opposite.

[0014] Further, the first plug is provided with a first light extinction sheet at the end close to the light path channel, and / or the second plug is provided with a second light extinction sheet at the end close to the light path channel.

[0015] Further, the light beam passes through the lens assembly, the first hole, the scattering space and the second hole in the light path channel in sequence and is received by the light trap.

[0016] Further, the lens assembly comprises a first cylindrical lens and a second cylindrical lens, the convex surface of the first cylindrical lens faces the convex surface of the second cylindrical lens; the normal line of the first cylindrical lens and the normal line of the second cylindrical lens are perpendicular to each other.

[0017] Further, the scattered light collection assembly comprises a mirror and a photodetector, the mirror and the photodetector are arranged at two ends of the scattered light collection receiving channel respectively.

[0018] Further, the gas path assembly comprises an air inlet pipe and an air outlet pipe arranged at two ends of the gas path channel, the to-be-measured gas enters the scattering space through the air inlet pipe and is discharged through the air outlet pipe.

[0019] Further, the surfaces of the light path channel, the scattered light collection receiving channel, the gas path channel and the hole groove are provided with light absorption layers.

[0020] Compared with the prior art, the utility model has the advantages that the light path channel, the scattered light collection receiving channel and the gas path channel are arranged in the X direction, the Y direction and the Z direction inside the shell respectively, the three channels meet in the scattering space, the hole groove is arranged in the shell along the direction of the light path channel, the stray light on the light path channel is reduced, the extinction effect of the light trap is improved, and the generated stray light is maximized. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] ATTACHED Figure 1 It is the principle view of a kind of particle counter of the application.

[0023] The reference signs and component parts involved in the drawings are explained as follows:

[0024] 1, shell; 2, laser; 3, light path channel; 4, scattered light collection receiving channel; 5, gas path channel; 6, lens assembly; 61, first cylindrical lens; 62, second cylindrical lens; 7, light trap; 8, gas path assembly; 9, scattered light collection assembly; 91, mirror; 92, photodetector; 10, first hole groove; 11, second hole groove; 12, first blocking piece; 13, second blocking piece; 14, first extinction sheet; 15, second extinction sheet; 16, third blocking piece; 17, third extinction sheet; 18, scattering space. DETAILED DESCRIPTION

[0025] The technical solutions of the utility model will be described clearly and completely through specific embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model, not all. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.

[0026] Referring to the accompanying drawings Figure 1 As shown in the drawings, a particle counting sensor of the application comprises a shell 1 and a laser 2 for emitting a light beam, a scattering space 18 is formed in the shell 1, in other embodiments, the selection of the type of laser 1 has multiple options for the consideration of cost and measurement accuracy, which can be a semiconductor laser, a fiber laser. Figure 1 The horizontal direction is the X direction, the vertical direction is the Y direction, and the Z direction is perpendicular to the X direction and the Y direction; the shell 1 is internally provided with a light path channel 3 along the X direction, a scattered light collection receiving channel 4 along the Y direction, and a gas path channel 5 along the Z direction; the light path channel 3, the scattered light collection receiving channel 4 and the gas path channel 5 all pass through the shell 1, and the light path channel 3, the scattered light collection receiving channel 4 and the gas path channel 5 meet in the scattering space 18; in this embodiment, the X direction, the Y direction and the Z direction are perpendicular to each other. The laser 2 is arranged on the light path channel 3 at the end of the shell 1, and a lens assembly 6 and a light trap 7 are arranged along the light propagation path in the light path channel 3; the light beam emitted by the laser 2 is sequentially received by the lens assembly 6 and the light trap 7 after passing through the lens assembly 6 and the scattering space. At the same time, the gas path channel 5 is provided with a gas path assembly 8 for the flow of the measured gas flow, and the scattered light collection receiving channel 4 is provided with a scattered light collection assembly 9.

[0027] In order to reduce stray light on the light path and improve the extinction effect of the light trap, maximize the reduction of stray light, one or more holes are formed in the shell 1, which overlap with the light path channel 4 and are arranged on the front and rear sides of the scattering space along the light beam propagation direction; the opening of the hole is provided with a plug matched with the opening; the hole is communicated with the light path channel 3 and forms a pit on the inner side of the light path channel 3. The hole of the embodiment comprises a first hole 10 and a second hole 11, the opening of the first hole 10 is provided with a sleeved first plug 12, and the first hole 10 forms a pit on one side or both sides of the light path channel 4 after being plugged by the first plug 12; similarly, the opening of the second hole 11 is provided with a sleeved second plug 13, and a pit is also formed on one side or both sides of the light path channel 4.

[0028] The light trap 7 extends at least partially into the second hole slot 11, and the light trap 7 comprises a third block 16 which is sleeved with the light path channel 3, and a third light extinction sheet 17 which is obliquely arranged at one end of the third block 16 close to the scattering space 18. The angle θ1 between the surface of the third light extinction sheet 17 and the end surface of the second block 13 close to the light path channel 3 is 40°-50°, preferably 45°, and the angle θ2 of the light on the optical axis of the light beam on the third light extinction sheet 17 is 40°-50°, preferably 45°. The light beam is attenuated after being incident to the third light extinction sheet 17 after passing through the scattering space 18, and part of the light which is not attenuated is reflected to the end surface of the second block 13.

[0029] Preferably, referring to the accompanying drawings, the first block 12 in the embodiment is provided with a first light extinction sheet 14 at one end close to the light path channel 3. Preferably, the second block 13 is provided with a second light extinction sheet 15 at one end close to the light path channel 3. When the second block 13 is provided with the second light extinction sheet 15 at one end close to the light path channel 3, i.e. the angle between the second light extinction sheet 15 and the third light extinction sheet 17 is 40°-50°, the light which is not attenuated is received and attenuated by the second light extinction sheet 15. Figure 1

[0030] The opening directions of the first hole slot 10 and the second hole slot 11 are opposite. Along the propagation direction of the light beam, the first hole slot 10 and the second hole slot 11 are respectively arranged at both sides of the scattering space 18 along the propagation direction of the light beam of the laser 2. The first hole slot 10 is arranged after the lens assembly 6 along the propagation direction of the light beam, so that the light beam is sequentially absorbed by the light trap 7 after passing through the lens assembly 6, the first hole slot 11, the scattering space 18 and the second hole slot 12 along the light path channel 3. Here, the laser 2, the lens assembly 6 and the light trap 7 are installed and arranged on the light path channel 3, and the laser 3 and the light trap 7 are respectively installed and arranged at both ends of the light path channel 3.

[0031] ​The lens assembly 6 inside the light path channel 4 includes a first cylindrical lens 61 and a second cylindrical lens 62, the convex surface of the first cylindrical lens 61 faces the convex surface of the second cylindrical lens 62, the normal line of the first cylindrical lens 61 is perpendicular to the normal line of the second cylindrical lens 62, for example, the first cylindrical lens 61 collimates the fast axis of the light beam, and the second cylindrical lens 62 collimates the slow axis of the light beam. The light beam emitted by the laser 2 is incident from the plane of the first cylindrical lens 61, is emitted from the convex surface of the first cylindrical lens 61, is compressed and collimated in the fast axis direction of the light beam, is then incident from the convex surface of the second cylindrical lens 62, and is emitted from the plane of the second cylindrical lens 62, is compressed and collimated in the slow axis direction of the light beam. The lens assembly 6 of the particle counter in this embodiment uses cylindrical lenses with convex surfaces arranged opposite to each other to shape the light beam. By shaping the light beam, that is, compressing and collimating the light beam in the fast axis and slow axis directions, the light beam is guided to the scattering space. This enables the particle counter to obtain a more uniform flat-top light beam, so that the spot light intensity in the scattering space is more uniform, and also reduces stray light during the process of removing the light beam from the laser to the light trap.

[0032] The scattering light collection assembly 9 in the scattering light collection channel 4 includes a mirror 91 and a photodetector 92, the mirror 91 and the photodetector 92 are respectively arranged at two ends of the scattering light collection receiving channel 4, and are both arranged in combination with the shell wall of the shell 1. The mirror 91 collects the scattering light of the particles to be measured and reflects it to the photodetector 92, and the photodetector 92 converts the received scattering light of the particles to be measured into an electrical signal. The photodetector 92 and the mirror 91 are arranged to satisfy a geometric optical relationship, and the scattering light of the particles to be measured can be directly received by the photodetector 92 in part, and the other part is collected by the mirror 91 and then delivered to the photodetector 92. The photodetector 92, such as a photodiode or a photomultiplier tube, converts the received light signal into an electrical signal.

[0033] The gas flow to be measured flows into the scattering space from the gas path channel 5, and the gas path assembly 8 arranged in the gas path channel 5 includes an air inlet pipe and an air outlet pipe arranged in combination with the two ends of the gas path channel 5. The gas flow to be measured enters the inside of the shell 1 through the air inlet pipe, passes through the overlapping area of the light path channel 3, the scattering light collection receiving channel 4 and the gas path channel 5 to form a scattering space, and is then discharged through the air outlet pipe. The air outlet of the air inlet pipe and the air inlet of the air outlet pipe are coaxial, and the air outlet of the air inlet pipe is smaller than the air inlet of the air outlet pipe. Here, the light beam and the gas flow to be measured form a light-sensitive area, and the particles in the gas flow to be measured excite the scattering light of the particles in the light-sensitive area. The light-sensitive area is located between the air outlet of the air inlet pipe and the air inlet of the air outlet pipe.

[0034] The third light extinction sheet 17 can be arranged on the side of the housing 1 facing the gas path assembly 8, and can be arranged on the side of the housing 1 facing the inlet pipe or the outlet pipe. It can be understood that the third block 16 has an inclined end surface close to the scattering space, and the third light extinction sheet 17 can be arranged obliquely.

[0035] The first / second / third light extinction sheet is an attenuation sheet, and the light effective attenuation rate is greater than 99%.

[0036] Preferably, referring to FIG. 1, the light path channel 3, the scattered light collection and receiving channel 4, the gas path channel 5, and the surface of the hole groove are provided with a light absorption layer. Figure 1 Preferably, referring to FIG. 1, the light path channel 3, the scattered light collection and receiving channel 4, the gas path channel 5, and the surface of the hole groove are provided with a light absorption layer.

[0037] Preferably, referring to FIG. 1, the light path channel 3, the scattered light collection and receiving channel 4, the gas path channel 5, and the surface of the hole groove are provided with a light absorption layer. Figure 1 Preferably, referring to FIG. 1, the light path channel 3, the scattered light collection and receiving channel 4, the gas path channel 5, and the surface of the hole groove are provided with a light absorption layer.

[0038] In the present application, the light beam and the scattered light are processed by using a light processing structure including lenses, mirrors, and detectors. The first cylindrical lens 61 and the second cylindrical lens 62 are used for receiving and / or projecting the light beam. The mirror 91 and the detector are used for receiving and / or projecting the light beam excited by the particles in the measured gas flow to emit the scattered light. As an implementable manner, the position relationship between the mirror, the condenser lens, and the detector satisfies the object-image relationship of the optical system. For example, the detector is arranged at the focal point or the near focal point of the corresponding mirror.

[0039] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A particle counting sensor, characterized by, The application relates to a laser device for measuring gas flow, which comprises a shell and a laser for emitting a light beam, wherein a scattering space is formed in the shell, a light path channel is formed in the shell along an X direction, a scattering light collecting and receiving channel is formed in the shell along a Y direction, and a gas path channel is formed in the shell along a Z direction; the light path channel, the scattering light collecting and receiving channel and the gas path channel all pass through the shell and meet in the scattering space. The laser is arranged on the light path channel at the end of the shell, a lens assembly and a light trap are arranged along a light beam propagation path in the light path channel, the light beam is sequentially passed through the lens assembly and the scattering space and is absorbed by the light trap; a gas path assembly for the flow of a to-be-measured gas flow is arranged on the gas path channel, and a scattering light collecting assembly is arranged on the scattering light collecting and receiving channel. Holes are formed in the front and rear of the scattering space of the shell, the hole groove partially overlaps with the light path channel, a plug block is arranged at the opening of the hole groove, and the hole groove is communicated with the light path channel and forms a pit on the inner side of the light path channel.

2. A particle counting sensor according to claim 1, wherein, The hole groove comprises a first hole groove and a second hole groove, the plug block comprises a first plug block and a second plug block, the first plug block is sleeved on the opening of the first hole groove, and the second plug block is sleeved on the opening of the second hole groove.

3. A particle counting sensor according to claim 2, wherein, The light trap at least partially extends into the second hole groove, the light trap comprises a third plug block which is sleeved with the light path channel, and a third light extinction sheet which is arranged in a slanting manner at one end of the third plug block close to the scattering space. The included angle theta1 between the surface of the third light extinction sheet and the end surface of the second plug block close to the light path channel is 40-50 degrees, and the incidence angle theta2 of the light on the optical axis of the light beam on the third light extinction sheet is 40-50 degrees.

4. A particle counting sensor according to claim 2, wherein, The opening directions of the first hole groove and the second hole groove are opposite.

5. A particle counting sensor according to claim 2, wherein, The first plug block is provided with a first light extinction sheet at one end close to the light path channel, and / or the second plug block is provided with a second light extinction sheet at one end close to the light path channel.

6. A particle counting sensor according to claim 2, wherein, The light beam sequentially passes through the lens assembly, the first hole groove, the scattering space and the second hole groove along the light path channel and is received by the light trap.

7. A particle counting sensor according to claim 1, wherein, The lens assembly comprises a first cylindrical lens and a second cylindrical lens, the convex surface of the first cylindrical lens faces the convex surface of the second cylindrical lens, and the normal line of the first cylindrical lens is perpendicular to the normal line of the second cylindrical lens.

8. A particle counting sensor according to claim 1, wherein, The scattering light collecting assembly comprises a reflecting mirror and a photodetector, and the reflecting mirror and the photodetector are arranged at two ends of the scattering light collecting and receiving channel respectively.

9. A particle counting sensor according to claim 1, wherein, The gas path assembly comprises an air inlet pipe and an air outlet pipe which are arranged in combination with two ends of the gas path channel, and the to-be-measured gas flow enters the scattering space through the air inlet pipe and is discharged through the air outlet pipe.

10. A particle counting sensor according to claim 1, wherein, Surfaces of the light path channel, the scattering light collecting and receiving channel, the gas path channel and the hole groove are all provided with light absorption layers.

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