Dust monitor and its working method

Abstract

The present invention provides a dust monitor and a working method thereof, wherein the working method of the dust monitor comprises a measuring stage and a calibration stage; the calibration stage is as follows: a light source emits a measuring light; a rotating part of a calibration chamber rotates to a first working state, the measuring light is blocked by an optical window having a zero transmittance to the measuring light on the rotating part, the light emitted from the calibration chamber enters a detector, and a zero point calibration is performed according to an output signal of the detector; as the rotating part rotates, the measuring light passes through optical windows having different transmittances to the measuring light in different time periods, the transmittance of the optical windows to the measuring light is between 0 and 100%, and then passes through the interior of the calibration chamber and an exit window, the scattered light emitted from the calibration chamber enters the detector, and a range and linear calibration is performed according to the output signal of the detector. The present invention has the advantages of convenient and accurate calibration.

Description

Technical Field

[0001] The invention relates to dust detection, in particular to a dust monitor and a working method thereof. Background Art

[0002] Sulfur dioxide, nitrogen oxides and inhalable particulate matter are the main components of haze. The first two are gaseous pollutants, and the last particulate matter is the culprit that aggravates haze weather pollution. There are many types of particulate matter suspended in the air. A large amount of data shows that the length of exposure to an environment with excessive concentration of particulate matter is closely related to various health indicators of the human body. At the same time, suspended particulate matter scatters and blocks the radiation of sunlight to the earth, hindering part of the solar energy and affecting the temperature; in addition, dust particles also have varying degrees of influence on the pH value of precipitation and the growth and photosynthesis of plants. Particle monitoring is the basic work of environmental protection and the technical basis for environmental law enforcement supervision. Monitoring data can be used as a legal basis for environmental law enforcement supervision, and its technical level plays a vital role in grasping the current status of pollution and predicting development trends.

[0003] At present, the measurement of particle concentration is divided into two categories: sampling method and non-sampling method. The sampling method, also known as the filtration weighing method, is a national standard method; the non-sampling method is a method of indirectly measuring the concentration of smoke dust by using the attenuation and scattering phenomena produced by the interaction of smoke dust particles with rays, light, etc. Among the non-sampling methods, the light scattering method can be monitored online, which is convenient for real-time measurement and is widely used in industry. In the dust monitor of the light scattering method, the calibration of the instrument plays a vital role in the measurement results of the particle matter.

[0004] At present, the zero-point and range calibration schemes of dust monitors based on the laser backscattering method generally use structural parts inserted into the instrument to realize the calibration function, but the structural parts require manual operation and cannot automatically realize the calibration function. Although the zero-point calibration and range calibration in some instruments can be automated, the zero-point calibration uses the laser-off scheme, and the laser is turned on for range calibration. It takes a certain amount of time for the laser to be turned on and the power is constant. The process is time-consuming, and this method easily ignores the impact of the laser circuit or laser noise on the detection results.

[0005] During range calibration, optical reflectors or optical fibers are used to change the optical path so that the laser light is reflected directly into the detector without passing through the flue. The installation and fixation of the reflectors and optical fibers have strict requirements on the angles, which increases the complexity and cost of the instrument. In addition, when this solution calibrates multiple detectors at the same time, it is necessary to use a beam splitter (beam splitter or Y-type optical fiber) to divide the laser light into several parts and then introduce them into the detector. The optical path is complex and costly, and the optical fiber is easily affected by the environment and is unstable.

[0006] At present, the calibration methods of most dust monitors in China mainly include zero point calibration and range calibration, but do not include linear calibration. Dust monitors such as SICK and DRUGE abroad are equipped with linear calibration function, which can effectively improve the linearity of the instrument and improve the accuracy of measurement. However, linear calibration requires manual installation of attenuation sheets with different transmittances for calibration, which is cumbersome. Summary of the invention

[0007] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a calibration method for a dust monitor.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] The working method of the dust monitor includes a measurement phase and a calibration phase; the calibration phase is:

[0010] The light source emits a measuring light;

[0011] The rotating part of the calibration chamber rotates to a first working state, the measuring light is blocked by an optical window on the rotating part whose transmittance to the measuring light is zero, the light emitted from the calibration chamber enters the detector, and zero point calibration is performed according to the output signal of the detector;

[0012] The rotating part rotates to the second working state, the measuring light passes through the optical window with a transmittance of 100% for the measuring light on the rotating part, the interior of the calibration chamber and the exit window, the light exiting from the calibration chamber enters the detector, and the range calibration is performed according to the output signal of the detector; the exit window is fixedly arranged, and the standard scatterer is arranged at the exit window;

[0013] As the rotating part rotates, the measuring light passes through optical windows with different transmittances to the measuring light in different time periods, and the transmittance of the optical windows to the measuring light is between 0 and 100%, and then passes through the interior of the calibration chamber and the exit window. The light exiting from the calibration chamber enters the detector, and linear calibration is performed based on the output signal of the detector. The standard scatterer is arranged at the exit window.

[0014] Another object of the present invention is to provide a dust monitor for implementing the working method of the present invention, and the object of the invention is achieved through the following technical solutions:

[0015] A dust meter for implementing the working method of the dust meter of the present invention, the dust meter comprises a light source and a detector, the light source is used to emit measurement light; the dust meter also comprises:

[0016] A calibration chamber, the calibration chamber comprising a rotating part and a fixed part, one end of the rotating part is arranged on a bracket, and the rotating part and the fixed part form a closed cavity; the radial part of the rotating part has a plurality of optical windows with different transmittances to the measuring light, and the radial part of the fixed part has an exit window and a central through hole;

[0017] a first driving unit, the first driving unit being used to drive the rotating part to rotate;

[0018] A shielding component, on which a standard scatterer is arranged;

[0019] A second driving unit, wherein the second driving unit is used to use the shielding component to shield the central through hole as needed, and to make the standard scatterer shield the exit window.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] An optical window with different transmittances for measuring light is arranged on the rotating part of the calibration room. As the rotation occurs, the measuring light is incident on the optical window with different transmittances at different times. A standard scatterer is arranged at the emission window of the fixed part of the calibration room as required. Zero point calibration, range calibration and linear calibration are performed according to the light received by the detector.

[0022] 1. The calibration function is concentrated in one calibration room with high integration, including zero point calibration, range calibration, linear calibration and measurement functions. The calibration is realized automatically without manual replacement of filters, which simplifies the calibration process.

[0023] 2. The stepper motor drives the rotating part, so that each optical window can be accurately positioned, improving the calibration accuracy and repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings:

[0025] Figure 1 Schematic diagram of the structure of the calibration method of the dust monitor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Figure 1The following description describes the optional embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to explain the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional embodiments, but is only limited by the claims and their equivalents.

[0027] Example 1.

[0028] Figure 1 A schematic diagram of a calibration method for a dust monitor according to an embodiment of the present invention is provided. Figure 1 As shown, the working method of the dust monitor includes a measurement phase and a calibration phase; the calibration phase is:

[0029] The light source emits a measuring light;

[0030] The rotating part of the calibration chamber rotates to a first working state, the measuring light is blocked by an optical window on the rotating part whose transmittance to the measuring light is zero, the light emitted from the calibration chamber enters the detector, and zero point calibration is performed according to the output signal of the detector;

[0031] The rotating part rotates to the second working state, the measuring light passes through the optical window with a transmittance of 100% for the measuring light on the rotating part, the interior of the calibration chamber and the exit window, the light exiting from the calibration chamber enters the detector, and the range calibration is performed according to the output signal of the detector; the exit window is fixedly arranged, and the standard scatterer is arranged at the exit window;

[0032] As the rotating part rotates, the measuring light passes through optical windows with different transmittances to the measuring light in different time periods, and the transmittance of the optical windows to the measuring light is between 0 and 100%, and then passes through the interior of the calibration chamber and the exit window. The light exiting from the calibration chamber enters the detector, and linear calibration is performed based on the output signal of the detector. The standard scatterer is arranged at the exit window.

[0033] In order to realize the measurement automatically, further, the measurement stage is:

[0034] The light source emits a measuring light;

[0035] The rotating part of the calibration chamber rotates to the second working state, and the measuring light passes through the optical window with a transmittance of 100% on the rotating part, the interior of the calibration chamber and the exit window, and then enters the area to be measured. The scattered light in the area to be measured passes through the interior of the calibration chamber and is then received by the detector.

[0036] In order to accurately drive the rotating part to rotate, further, the rotating part enters the working state in the following manner:

[0037] The driving unit drives the part with a larger inner diameter to rotate, and drives the part with a smaller inner diameter to rotate on the bracket, so that the rotating part rotates to a working state, and the scattered light passes through the optical channel in the part with a smaller inner diameter and is received by the detector.

[0038] In order to form a closed space in the calibration chamber, further, during the rotation of the rotating part, the open end of the rotating part is located in the fixed part of the calibration chamber, the exit window is arranged on the fixed part, and the fixed part has a central through hole allowing external scattered light to pass through.

[0039] In order to switch between the calibration phase and the measurement phase, further, in the calibration phase, the central through hole is blocked, and in the measurement phase, the central through hole is opened, and the scattered light of the area to be measured passes through the central through hole.

[0040] A dust meter for implementing a dust meter calibration method, the dust meter comprising a light source and a detector, the light source being used to emit a measuring light; the dust meter further comprising:

[0041] A calibration chamber, the calibration chamber comprising a rotating part and a fixed part, one end of the rotating part is arranged on a bracket, and the rotating part and the fixed part form a closed cavity; the radial part of the rotating part has a plurality of optical windows with different transmittances to the measuring light, and the radial part of the fixed part has an exit window and a central through hole;

[0042] a first driving unit, the first driving unit being used to drive the rotating part to rotate;

[0043] A shielding component, on which a standard scatterer is arranged;

[0044] A second driving unit, wherein the second driving unit is used to use the shielding component to shield the central through hole as needed, and to make the standard scatterer shield the exit window.

[0045] In order to form a closed space in the calibration room, further, the rotating part includes:

[0046] A portion with a smaller inner diameter and a portion with a larger inner diameter, wherein the portion with a smaller inner diameter is rotatably arranged on a bracket and connected to the portion with a larger inner diameter; and a plurality of optical windows are arranged on the radial side of the portion with a larger inner diameter.

[0047] For accurate calibration, further, the central axes of the smaller inner diameter portion, the larger inner diameter portion and the central through hole are collinear, and the center point of the optical window in working state and the center point of the exit window are collinear with the incident measuring light.

[0048] In order to automatically drive the shielding component, further, the shielding component rotates around a rotation axis, and the rotation axis is arranged on the fixed part; the second driving unit adopts a solenoid.

[0049] In order to form a scattered light channel, further, the external scattered light passes through the central through hole, the interior of the larger inner diameter part and the smaller inner diameter part in sequence, and is then received by the detector.

[0050] Example 2.

[0051] An application example of the dust monitor and the working method thereof according to embodiment 1 of the present invention.

[0052] In this application example, Figure 1 As shown, the working method of the dust monitor includes a measurement phase and a calibration phase; the calibration phase is:

[0053] The light source emits a measuring light;

[0054] The rotating part of the calibration chamber rotates to a first working state, the measuring light is blocked by an optical window on the rotating part whose transmittance to the measuring light is zero, and under the drive of the second driving unit, the shielding component blocks the central through hole of the fixed part, and at the same time, the standard scatterer is arranged at the exit window of the fixed part; the light emitted from the calibration chamber enters the detector, and a zero point calibration is performed according to the output signal of the detector;

[0055] The rotating part rotates to the second working state, the measuring light passes through the optical window on the rotating part with a transmittance of 100% for the measuring light, the interior of the calibration chamber and the exit window, the shielding component blocks the central through hole of the fixed part, and at the same time, the standard scatterer is arranged at the exit window of the fixed part; the light emitted from the calibration chamber enters the detector, and the range calibration is performed according to the output signal of the detector;

[0056] As the rotating part rotates, the measuring light passes through the optical windows with different transmittances to the measuring light in different time periods, and the transmittances of the optical windows to the measuring light are between 0 and 100%, such as 20%, 50%, and 80%, and then passes through the inside of the calibration chamber and the exit window, and the shielding component blocks the central through hole of the fixed part. At the same time, the standard scatterer is arranged at the exit window of the fixed part; the light emitted from the calibration chamber enters the detector, and linear calibration is performed according to the output signal of the detector;

[0057] The measurement phase is:

[0058] The light source emits measuring light; driven by the second driving unit, the shielding component rotates, the central through hole of the fixed part opens, allowing the external scattered light to pass through the central through hole without obstruction, and at the same time, the standard scatterer is separated from the exit window;

[0059] The rotating part of the calibration chamber rotates to a second working state, and the measuring light passes through the optical window with a transmittance of 100% on the rotating part, the interior of the calibration chamber and the exit window, and then enters the area to be measured. The scattered light in the area to be measured passes through the central through hole and the interior of the calibration chamber (including the interior of the part with a larger inner diameter and the part with a smaller inner diameter) in sequence, and then is received by the detector;

[0060] In the above work, the rotating part enters the working state in the following manner:

[0061] The first driving unit drives the portion with a larger inner diameter of the rotating part to rotate, and drives the portion with a smaller inner diameter of the rotating part to rotate on the bracket, so that the rotating part rotates to a working state.

[0062] The dust monitor for implementing the dust monitor calibration method according to the embodiment of the present invention comprises a light source and a detector, wherein the light source is used to emit measurement light; the dust monitor further comprises:

[0063] A calibration chamber, the calibration chamber comprising a rotating part and a fixed part, one end of the rotating part is arranged on a bracket, and the rotating part and the fixed part form a closed cavity; the rotating part comprises a part with a smaller inner diameter and a part with a larger inner diameter, the part with a smaller inner diameter is rotatably arranged on the bracket and connected to the part with a larger inner diameter; a plurality of optical windows with different transmittances to the measuring light are arranged on the radial side of the part with a larger inner diameter; the radial part of the fixed part has an exit window and a central through hole; the central axes of the part with a smaller inner diameter, the part with a larger inner diameter and the central through hole are collinear, and the center point of the optical window in a working state and the center point of the exit window are collinear with the light of the incident measuring light.

[0064] a first driving unit, using a stepping motor and a belt, wherein the belt is wound around the stepping motor and the portion with a larger inner diameter, thereby driving the rotating portion to rotate;

[0065] A shielding component, on which a standard scatterer is arranged; the shielding component rotates around a rotation axis, and the rotation axis is arranged on the fixed part;

[0066] The second driving unit adopts a solenoid, and is used for using the shielding component to shield the central through hole as needed, and for making the standard scatterer shield the exit window.

Claims

1. A working method of a dust monitor, the working method of the dust monitor comprising a measurement phase and a calibration phase; characterized in that: The calibration phase is: The light source emits a measuring light; The rotating part of the calibration chamber rotates to a first working state, the measuring light is blocked by an optical window on the rotating part whose transmittance to the measuring light is zero, the light emitted from the calibration chamber enters the detector, and zero point calibration is performed according to the output signal of the detector; The rotating part rotates to a second working state, the measuring light passes through the optical window on the rotating part with a transmittance of 100% for the measuring light, the interior of the calibration chamber and the exit window, the light from the calibration chamber enters the detector, and the range calibration is performed according to the output signal of the detector; the exit window is fixedly arranged, and the standard scatterer is arranged at the exit window; As the rotating part rotates, the measuring light passes through optical windows with different transmittances to the measuring light in different time periods, and the transmittance of the optical windows to the measuring light is between 0 and 100%, and then passes through the interior of the calibration chamber and the exit window. The light exiting from the calibration chamber enters the detector, and linear calibration is performed based on the output signal of the detector. The standard scatterer is arranged at the exit window.

2. The working method of the dust monitor according to claim 1, characterized in that: The measurement phase is: The light source emits a measuring light; The rotating part of the calibration chamber rotates to the second working state, and the measuring light passes through the optical window with a transmittance of 100% on the rotating part, the interior of the calibration chamber and the exit window, and then enters the area to be measured. The scattered light in the area to be measured passes through the interior of the calibration chamber and is then received by the detector.

3. The working method of the dust monitor according to claim 1, characterized in that: The way in which the rotating part enters the working state is: The driving unit drives the part with a larger inner diameter to rotate, and drives the part with a smaller inner diameter to rotate on the bracket, so that the rotating part rotates to a working state, and the scattered light passes through the optical channel in the part with a smaller inner diameter and is received by the detector.

4. The working method of the dust monitor according to claim 1, characterized in that: During the rotation of the rotating part, the open end of the rotating part is located in the fixed part of the calibration chamber, the exit window is arranged on the fixed part, and the fixed part has a central through hole allowing external scattered light to pass through.

5. The working method of the dust monitor according to claim 4, characterized in that: In the calibration phase, the central through hole is blocked, and in the measurement phase, the central through hole is opened, and scattered light of the area to be measured passes through the central through hole.

6. A dust monitor for implementing the working method of the dust monitor according to any one of claims 1 to 5, the dust monitor comprising a light source and a detector, the light source being used to emit measurement light; characterized in that: The dust monitor also includes: A calibration chamber, the calibration chamber comprising a rotating part and a fixed part, one end of the rotating part is arranged on a bracket, and the rotating part and the fixed part form a closed cavity; the radial part of the rotating part has a plurality of optical windows with different transmittances to the measuring light, and the radial part of the fixed part has an exit window and a central through hole; a first driving unit, the first driving unit being used to drive the rotating part to rotate; A shielding component, on which a standard scatterer is arranged; A second driving unit, wherein the second driving unit is used to use the shielding component to shield the central through hole as needed, and to make the standard scatterer shield the exit window.

7. The dust monitor according to claim 6, characterized in that: The rotating part comprises: A portion with a smaller inner diameter and a portion with a larger inner diameter, wherein the portion with a smaller inner diameter is rotatably arranged on a bracket and connected to the portion with a larger inner diameter; and a plurality of optical windows are arranged on the radial side of the portion with a larger inner diameter.

8. The dust monitor according to claim 6, characterized in that: The central axes of the smaller inner diameter portion, the larger inner diameter portion and the central through hole are collinear, and the center point of the optical window in working state and the center point of the exit window are collinear with the incident measuring light.

9. The dust monitor according to claim 6, characterized in that: The shielding component rotates around a rotation axis, and the rotation axis is arranged on the fixed part; the second driving unit adopts a solenoid.

10. The dust monitor according to claim 7, characterized in that: The external scattered light passes through the central through hole, the interior of the part with a larger inner diameter and the part with a smaller inner diameter in sequence, and is then received by the detector.

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