Light scattering type dust concentration sensor self-zero calibration device and method

Abstract

The invention relates to a light scattering type dust concentration sensor self-zero calibration device and method, and belongs to the field of dust sensors. The device comprises a light scattering detection unit and a shell, the light scattering detection unit is located in the shell and comprises a photoelectric sensor, a laser light source and an optical lens group, and the device is characterized by further comprising a micro fan and a replaceable filter screen; the photoelectric sensor is mounted on the left side in the shell to realize rapid detection of dust concentration; the micro fan is mounted on the right side in the shell, so that power consumption is reduced as much as possible; when on-site in-situ self-zeroing needs to be carried out, a replaceable filter screen is additionally arranged on the air inlet side of the micro fan, it is guaranteed that air blown to the photoelectric sensor after the micro fan is started is clean airflow, dust in the shell is all blown to the outside, meanwhile, it is guaranteed that external dust does not enter the shell, data of the photoelectric sensor is collected at the moment, and the self-zeroing effect is achieved. And the self-zero calibration of the light scattering type dust concentration sensor is realized. The precision of the dust concentration sensor can be improved.

Description

Technical Field

[0001] The invention belongs to the field of dust sensors and relates to a self-zeroing device and method for a light scattering dust concentration sensor. Background Art

[0002] There are many methods for detecting dust particles: weighing method, light flash method, beta ray method, micro-oscillating balance method, etc. Among these methods, light scattering method has the advantages of fast detection speed, good repeatability, and timely data processing, and is widely used in dust concentration detection.

[0003] Light scattering refers to the phenomenon that light deviates from its original propagation direction and spreads in all directions when passing through an uneven medium. Dust particles will produce scattered light when they are irradiated by light. The scattered light signal is strong when the particles are large, and the intensity of the scattered light is proportional to the particle size. When light waves pass through air with suspended particles, they will have characteristics such as refraction and absorption, resulting in energy dissipation and light intensity attenuation.

[0004] The patent with publication number CN108169089A discloses a laser dust sensor and a dust concentration sampling and zeroing measurement method. Specifically, the dust concentration is detected in a darkroom structure using the laser scattering principle. The dust concentration value is collected once per second, and the collection is divided into two time periods per second, one is the collection with laser irradiation and the other is the collection without laser irradiation. The signal collected without light irradiation is used as the zeroing signal and regarded as a dust-free environment. Then, the signal collected with light irradiation is compared with the zeroing signal each time, thereby realizing real-time calibration of the sensor. There are certain defects in the zeroing of this method. The dust zero point is the scattered light intensity (also called background scattered light intensity) when there is no dust under laser irradiation. There is no scattered light intensity (background scattered light intensity) without laser irradiation. The zero point calibration performed in this way is inaccurate.

[0005] Therefore, in order to further improve the accuracy of the light scattering dust concentration sensor, it is urgent to design a zero calibration method. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a self-zeroing device and method for a light scattering dust concentration sensor, which adds a self-zeroing device based on an unpowered dust concentration detection structure, thereby realizing self-zeroing calibration of the dust concentration sensor while reducing the power consumption of the entire machine, thereby improving the accuracy of the dust concentration sensor.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A light scattering dust concentration sensor self-zeroing device, comprising a micro fan, a replaceable filter, a light scattering detection unit and a housing; the light scattering detection unit is located in the housing, and specifically comprises a photoelectric sensor, a laser light source and an optical lens group; the device also comprises;

[0009] The photoelectric sensor is installed on the left side of the housing to achieve rapid detection of dust concentration; the micro fan is installed on the right side of the housing to reduce power consumption as much as possible;

[0010] When on-site in-situ self-calibration is required, a replaceable filter is added to the air inlet side of the micro fan to ensure that the air blowing to the photoelectric sensor after the micro fan is turned on is clean airflow, which will blow all the dust inside the casing to the outside while ensuring that the external dust does not enter the casing. At this time, the data of the photoelectric sensor is collected to realize the self-calibration of the light scattering dust concentration sensor.

[0011] Furthermore, the device combines the dust concentration detection algorithm to design an in-situ self-calibration zeroing algorithm for dust concentration. The specific self-calibration zeroing algorithm is:

[0012] Calculate the measured dust concentration C:

[0013]

[0014] Among them, λ is the wavelength of incident light, I0 is the incident light intensity, d is the diameter of dust particles, ρ is the true density, and m is the refractive index, all of which are considered constants; θ is the scattering angle of the monitoring point, and I is the scattered light intensity of the monitoring point;

[0015] When C < 10 of the minimum value -1 At this time, C is returned to 0, and the dust concentration sensor achieves self-calibration of zero.

[0016] The beneficial effects of the present invention are:

[0017] (1) The optical detection unit of the device of the present invention adopts a non-powered dust concentration detection structure, which can greatly reduce the power consumption of the whole machine and improve the field applicability of the sensor.

[0018] (2) The device of the present invention adds a micro fan and a quickly replaceable filter to the unpowered dust concentration detection structure to achieve self-zero calibration of the dust concentration sensor, thereby improving the accuracy of the dust concentration sensor.

[0019] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0021] Figure 1 It is a schematic diagram of the structure of the self-zeroing device of the light scattering dust concentration sensor of the present invention. DETAILED DESCRIPTION

[0022] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0023] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0024] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0025] The present invention adopts a technical solution based on the characteristics of the light scattering dust concentration sensor. Figure 1 The optical detection unit adopts a non-powered dust concentration detection structure, which can greatly reduce the power consumption of the whole machine and improve the field applicability of the sensor.

[0026] A photoelectric sensor is still used on the left side of the light scattering detection unit to achieve rapid detection of dust concentration, while a micro fan is used on the right side to minimize power consumption; when on-site in-situ self-calibration is required, a replaceable filter is added to the front end of the micro fan to ensure that the air blowing to the photoelectric sensor after the micro fan is turned on is clean airflow, which will blow all the dust inside the optical detection unit to the outside, while ensuring that the external wind and dust do not enter the optical detection unit. At this time, the data of the photoelectric sensor is collected to achieve self-calibration of the light scattering dust concentration sensor. Combined with the dust concentration detection algorithm, the dust concentration in-situ self-calibration zero algorithm is studied to further improve the detection accuracy of dust concentration.

[0027] The algorithm for self-calibration is as follows:

[0028] Calculate the measured dust concentration C:

[0029]

[0030] Among them, λ is the wavelength of incident light, I0 is the incident light intensity, d is the diameter of dust particles, ρ is the true density, and m is the refractive index, all of which are considered constants; θ is the scattering angle of the monitoring point, and I is the scattered light intensity of the monitoring point;

[0031] When C < 10 of the minimum value -1 At this time, C is returned to 0, and the dust concentration sensor achieves self-calibration of zero.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A self-zeroing device for a light scattering dust concentration sensor, comprising a light scattering detection unit and a housing, wherein the light scattering detection unit is located within the housing and specifically comprises a photoelectric sensor, a laser light source, and an optical lens assembly, characterized in that: The device also includes a micro-blower and replaceable filters; The photoelectric sensor is installed on the left side of the housing to achieve rapid detection of dust concentration; the micro fan is installed on the right side of the housing; When on-site in-situ self-calibration is required, a replaceable filter is added to the air inlet side of the micro fan to ensure that the air blowing to the photoelectric sensor after the micro fan is turned on is clean airflow, which blows all the dust inside the shell to the outside while ensuring that the external dust does not enter the shell. At this time, the data of the photoelectric sensor is collected to realize the self-calibration of the light scattering dust concentration sensor.

2. The self-zeroing device for a light scattering dust concentration sensor according to claim 1, characterized in that: The device combines the dust concentration detection algorithm to design the dust concentration in-situ self-calibration zero algorithm. The specific self-calibration zero algorithm is: Calculate the measured dust concentration C: Where λ is the wavelength of incident light, I0 is the incident light intensity, d is the diameter of dust particles, ρ is the true density, and m is the refractive index; θ is the scattering angle of the monitoring point, and I is the scattered light intensity at the monitoring point; When C < 10 of the lowest value -1 At this time, C is returned to 0, and the dust concentration sensor achieves self-calibration zero calibration.

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