DETECTION METHOD FOR CONCENTRATION OF FLUID PARTICULATE MATTER

Abstract

A method for detecting the concentration of particles in a fluid is disclosed. The method comprises the steps of: S1: introducing a pure fluid into a detection device to obtain a scatter background noise value U noise output by the detection device; S2: introducing a fluid to be detected into the detection device, obtaining scatter signals output by the detection device, and obtaining voltage signals of standard particles; S3: sampling signals of the fluid in a certain period of time, extracting effective signals, carrying out threshold value analysis on the effective signals Ux obtained by sampling, and obtaining the number of particles present in the period of time; and S4: obtaining the concentration of the particles in the fluid according to the number of particles in S3. According to this method, the accuracy in calculation of the concentration of particles in a fluid can be effectively improved.

Claims

1. A method for detecting concentration of particles in a fluid, comprising steps of: S1: introducing a pure fluid into a detection device to obtain a scatter background noise value U.sub.background noise output by the detection device; S2: introducing a fluid to be detected into the detection device, obtaining scatter signals output by the detection device, and obtaining voltage signals of standard particles; S3: sampling signals of the fluid in a period of time, extracting effective signals, carrying out a threshold value analysis on the effective signals U.sub.x obtained by sampling, and obtaining a number of particles present in the period of time; and S4: obtaining concentration of the particles in the fluid according to the number of the particles in S3.

2. The method according to claim 1, wherein the standard particles are selected from particles having a diameter of 10 m, with a corresponding voltage signal of U.sub.10 m.

3. The method according to claim 1, wherein the effective signals is extracted by comparing sampled signals with the scatter background noise value, and selecting signals greater than the scatter background noise value as the effective signals.

4. The method according to claim 1, wherein the step of obtaining the number of the particles through the threshold analysis in S3 comprises step of: comparing the obtained signal U.sub.x with the background noise value U.sub.background noise, if U.sub.xU.sub.background noise>0, adding 1 to a count, and if U.sub.xU.sub.background noise<0, the count being zero.

5. The method according to claim 1, wherein the step for obtaining the particle concentration in S4 comprises steps of: S41: calculating volume V.sub.x of the particles: $V_x=K{V}_{10.Math.\mathrm{.Math.m}}\sqrt{\frac{U_x-U_{\mathrm{background}.Math..Math.\mathrm{noise}}}{U_{10.Math..Math.m}-U_{\mathrm{background}.Math..Math.\mathrm{noise}}}}$ where V.sub.x represents volume of unknown particles; K represents a sensor correction coefficient; V.sub.10 m represents volume of the standard particles; U.sub.x represents output voltage amplitude of an unknown volume of the particles; U.sub.10 m represents output voltage amplitude of the standard particles; and S42: obtaining the concentration of the particles in the fluid: obtaining fluid flow velocity v, cross-sectional area S of the detection pipeline, converting number and volume of the particles passing through the pipeline in a period of time t into a total mass m, and obtaining particle concentration c through the following formula: $c=\frac{m}{vtS}.Math.\left(\mathrm{.Math.g}/m^3\right)$

Description

DETAILED DESCRIPTION

[0035] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0036] In order to further illustrate the technical means of the present invention for achieving the intended purposes thereof as well as effects, the following detailed description is made, taken in conjunction with the accompanying drawings and preferred embodiments, to illustrate specific embodiments, structures, features and efficacy thereof according to the present invention.

[0037] The invention discloses a method for detecting the concentration of particles in a fluid, comprises the steps of:

[0038] S1: introducing a pure fluid into a detection device to obtain a scatter background noise value U.sub.background noise output by the detection device;

[0039] S2: introducing a fluid to be detected into the detection device, obtaining scatter signals output by the detection device, and obtaining voltage signals of standard particles;

[0040] S3: sampling signals of the fluid in a certain period of time, extracting effective signals, carrying out threshold value analysis on the effective signals U.sub.x obtained by sampling, and obtaining the number of particles present in the period of time; and

[0041] S4: obtaining the concentration of the particles in the fluid according to the number of particles in S3.

[0042] A scatter background noise value U.sub.background noise output by a detection device is obtained, and the influence caused by the background noise value in a subsequent detection calculation process is removed, thereby improving the accuracy of the detection and calculation of the concentration of particles in the fluid.

[0043] In combination with the above embodiments, in one preferred embodiment thereof, the standard particles are selected from particles having a diameter of 10 m, with a corresponding voltage signal of U.sub.10 m.

[0044] In the actual selection process of the standard particles, if the particles are too large, the detection accuracy for the subsequent concentration calculation is decreased, and if the particles are too small, the detection sensitivity of the device is decreased, as a result the particle detection may fail. Therefore, the detection accuracy and the detection sensitivity can be effectively balanced by taking particles with a diameter of 10 m as standard particles by the inventor, on one hand the detection accuracy can be improved, and on the other hand the detection sensitivity can be improved.

[0045] In combination with the above embodiments, in one preferred embodiment thereof, the effective signal is extracted by comparing the sampled signals with the scatter background noise value, and selecting signals greater than the scatter background noise value as effective signals.

[0046] The sampled signals are compared with the previously obtained scatter background noise value, and signals greater than the scatter background noise value are used as the effective signals, so that the sampled signals show more practicability, and the subsequent measurement result is more accurate.

[0047] In combination with the above embodiments, in one preferred embodiment thereof, the step of obtaining the number of particles through a threshold analysis in S3 comprises the step of:

[0048] comparing the obtained signal U.sub.x with a background noise value U.sub.background noise, if U.sub.xU.sub.background noise>0, adding 1 to the count, and if U.sub.xU.sub.background noise<0, the count being zero.

[0049] In this step, as to the counting method, the inventor chooses preferably to compare the signal value with the background noise value instead of directly taking read-out values of the signal as the count, so that errors caused by the background noise value can be eliminated, that is, only signals when U.sub.xU.sub.background noise>0 are counted as representing particles, thereby rendering a more accurate detection result and an improved detection accuracy of the concentration of the particles.

[0050] In combination with the above embodiments, in another preferred embodiment, the step to obtain the particle concentration in S4 comprises the steps of:

[0051] S41: calculating the volume V.sub.x of the particles:

[00003]$V_x=K{V}_{10.Math.\mathrm{.Math.m}}\sqrt{\frac{U_x-U_{\mathrm{background}.Math..Math.\mathrm{noise}}}{U_{10.Math..Math.m}-U_{\mathrm{background}.Math..Math.\mathrm{noise}}}}$

[0052] where V.sub.x represents volume of unknown particles; K represents a sensor correction coefficient; V.sub.10 m represents standard particle volume; U.sub.x represents output voltage amplitude of an unknown volume of particles; U.sub.10 m represents output voltage amplitude of standard particles; and

[0053] S42: obtaining the concentration of the particles in the fluid:

[0054] Obtaining the fluid flow velocity v, the cross-sectional area S of the detection pipeline, converting the number and volume of particles passing through the pipeline in a period of time t into a total mass m, and obtaining the particle concentration c through the following formula:

[00004]$c=\frac{m}{vtS}.Math.\left(\mathrm{.Math.g}/m^3\right)$

[0055] In this step, elimination the influence of the background noise value is also taken into consideration, so that the detection result is more accurate. As in the above-mentioned calculation formula of the particles, factors of subtracting U.sub.background noise from U.sub.x and subtracting U.sub.background noise from U.sub.10 m, thereby rendering a calculated volume of the particles closer to the actual value, and improving the calculation accuracy of the concentration of the particles in the fluid.

[0056] The total mass m is calculated as follows:

[0057] Calculation of the mass of a single particle

m=V

[0058] The particle herein is regarded by default as a common particle in the fluid, a relative density of the particle is substituted into the above formula and the mass of a single particle can be obtained through conversion.

[0059] Accumulation of masses of particles in a period of time is performed on the basis of calculation of the mass of a single particle to obtain the total mass of the particles in the current period of time:

[00005]$M=\underset{i=1}{\overset{N}{.Math.}}.Math.m_i$

[0060] Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word about or approximately in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice; material, manufacturing, and assembly tolerances; and testing capability.

[0061] As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean at least one of A, at least one of B, and at least one of C.

[0062] The above-described embodiments are merely preferred embodiments of the present invention, and thus do not limit the scope of the present invention, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are intended to be within the scope of the present invention.