CN1303017A - In-line monitor method and device for flow and concentration of dust-contained airflow - Google Patents

Abstract

An in-line monitor method and its equipment for measuring the flow and concentration of dust-contained airflow features that the said flow and concentration can be calculated according to the dynamic pressure of probe and the resistance of pipeline. The antiblocking and antiwear measures are taken for the probe and the antiblocking measure is taken for the device to measure the resistance and static pressure of pipeline. Its advantages include high correctness and reliability.

Description

The on-line monitoring method and the device of dust-contained airflow flow and concentration

The invention belongs to fields of measurement, be specifically related to the on-line monitoring method and the device of a kind of dust-contained airflow flow and concentration.

China had once done comprehensive research in the eighties to the measuring technology of Dual-Phrase Distribution of Gas olid, comprised strength method, temperature method, capacitance method, laser method, supercritical ultrasonics technology, friction electrode method, Ke's mass flowmeter meter or the like.Also have the researcher once to carry out utilizing laser velocimeter to measure the exploration of Dual-Phrase Distribution of Gas olid, but the solid concentration that adapts to is minimum, is unsuitable for the requirement that higher dust concentration (in the station boiler pulverized coal preparation system, concentration is at 0.4-0.6kg/kg) is used; The researcher once did to improve to the strength method, utilized the single-unit fluid element to measure the Dual-Phrase Distribution of Gas olid flow, delivered paper, and this method is feasible in theory, but because it additionally increases resistance greatly to measured piping system, was difficult to drop into practical application.Also once did to utilize microwave, ray, electromagnetic field etc. to carry out the trial of dusty gas concentration and velocity survey, but all do not have the result who finally is applied to industrial practice.

The object of the present invention is to provide a kind of flow, the concentration that can measure dust-contained airflow accurately, reliably, and the method for on-line monitoring dust-contained airflow flow and concentration and device.

The step that realizes this method is as follows:

1) under the pure gas state, employing conventional criteria survey wind element---pitot tube is according to the average dynamic pressure Δ of the air-flow p in the uniform cross section method measuring channel _d, the differential pressure Δ p of the pipeline of usefulness probe measurement simultaneously inner control point ₀, probe 1 is demarcated, obtain the flow calibration coefficient k of probe _KbFor: $k_{\mathrm{kb}}=\sqrt{\frac{\mathrm{\Δ}{P}_d}{\mathrm{\Δ}{P}_0}}$

2) under the pure gas state, measure the resistance of each segment pipe of tested pipeline section, calculate the coefficient of frictional resistance λ of tested pipeline section according to resistance of ducting characteristic formula ₀Coefficient of shock resistance ξ with restricting element in the pipeline section and elbow ₀

3) choose according to pipe characteristic and contain frictional resistance correction factor k under the powdery attitude _λWith shock resistance correction factor k _ξ, calculate the concentration correction coefficient k of the resistance of ducting by following formula: $k=\frac{k_{\mathrm{\λ}}{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0{k}_{\mathrm{\ξ}}}{{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0}$

4) the flow calibration coefficient k of probe _Kb, the resistance of ducting the concentration correction coefficient k all be preset in the measurement calculation procedure of computing machine 6, measuring probe 1 is inserted in the pipeline of band dust, meet a total head of measuring air-flow to air-flow, air-flow back pressure of measuring air-flow obtains exporting differential pressure Δ p dorsad ₁Resistance of ducting differential pressure Δ p with 2 outputs of two hydrostatic measuring points ₂, and obtain static pressure p in the pipeline by hydrostatic measuring point 2-2 _s, obtain temperature t in the pipeline by measuring point 3;

5) by choosing atmospheric pressure p _a, according to the static pressure p that measures _sWith temperature t be by the current density ρ that the current density formula calculates in the pipeline: $\mathrm{\ρ}=1.293\×\frac{273}{273+t}\×\frac{p_a+p_s}{101325}---\mathrm{kg}/m^3$ 6) by probe differential pressure Δ p ₁, by probe differential pressure formula $\mathrm{\Δ}{P}_1=\frac{1}{2k_{\mathrm{kb}}^2}\mathrm{\ρ}{w}^2(1+k_{\mathrm{\μ}}\×\mathrm{\μ})$ Calculate concentration and be 0 o'clock wind speed w ₁, k wherein _μBe probe differential pressure concentration correction coefficient $w_1=k_{\mathrm{kb}}\sqrt{\frac{2\mathrm{\Δ}{p}_1}{\mathrm{\ρ}(1+k_{\mathrm{\μ}}\×\mathrm{\μ})}}$

7) calculating concentration according to the drag characteristic of pipeline by resistance of ducting characteristic formula is the resistance of ducting differential pressure Δ P during the pure gas state under the wind speed that draws of 0 o'clock step 6 ₂ ⁰, $\mathrm{\Δ}{P}_2^0=\frac{1}{2}\mathrm{\ρ}{w}^2({\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0)$ Resistance ratios R=Δ P then ₂/ Δ P ₂ ⁰, calculate concentration μ by formula R=1+k μ ₁: ${\mathrm{\μ}}_1=\frac{R-1}{k}$ 8) with the concentration value μ that obtains ₁, substitution probe differential pressure type Δ P ₁= $\frac{1}{2}$ k _Kbρ w ²(1+k _μ* μ), obtain the gas velocity w under this concentration ₂, the wind speed w that uses this step to obtain ₂Repeat aforementioned calculation, obtained the concentration value μ that calculates for the second time ₂, with the speed w that obtains ₂, concentration value μ ₂Computing velocity w with last time ₁, concentration value μ ₁Relatively, if error less than 0.5%, computing machine thinks and obtained gas velocity and dust concentration accurately, otherwise repeating step 7,8 until the speed that calculates for twice, concentration error less than O.5%:

9) show measurement result in real time by the on-Line Monitoring Program in the computing machine 6, and can pass through this program inquiring historical record.

A kind of device that designs according to said method, comprise probe 1, static pressure sniffer 2, temperature detection instrument 3, differential pressure transmitter, data acquisition board 5, computing machine 6, the anti-blocking probe 1 that it is characterized in that being used for measuring the ash-laden gas flow differential pressure is connected with differential pressure transmitter 4-1,2 hydrostatic measuring point 2-1 that the segment distance of being separated by on pipeline is arranged, 2-2 is connected with differential pressure transmitter 4-2, getting static pressure signal on hydrostatic measuring point 2-2 is connected with differential pressure transmitter 4-3, probe dynamic pressure difference and differential static pressure can be converted to the differential pressure transmitter 4-1 of current signal, 4-2,4-3 is electrically connected with data acquisition board 5, and the output of data acquisition board 5 is connected with computing machine 6 by data bus.

Described anti-blocking probe 1 comprises probe arm 7, buffer container 8, high pressure clean air pipeline 11, pressure tube 12, it is characterized in that two probe arms, 7 composition dynamic pressure probes, the end of stretching in the dust-contained airflow pipeline is made into wedge shape, a probe arm is met to dust-contained airflow, another is air-flow dorsad, the afterbody of two probe arms 7 is communicated with baffle-box 8, have static pressure tapping 13 in the end that two probe arms 7 stretch to dust-contained airflow, be connected with differential pressure transmitter (4-1) respectively by pressure tube 12.Described high pressure clean air enters in the buffer container through high pressure clean air pipeline 11, sprays in the dust-contained airflow through the probe arm again.

Described static pressure sniffer 2, comprise a buffer container 14, one vibrating-wire 15 is arranged in the buffer container 14, described vibrating-wire 15 stretches out buffer container 14 and enters baroport 16 on the pipeline wall, has on the top of buffer container 14 and pressure tube 16, scavenging duct 17, the hole 19,20,21 of forcing scavenging duct 18 to be communicated with.

Described vibrating-wire 15 1 ends are fixed on the top of buffer container 14 by connector 22, the bell 23 that the other end stretches out the buffer container lower end enters the baroport 16 on the pipeline wall, the orienting lug 24 of one definite vibrating-wire 15 directions is arranged on bell 23 internal faces, and described vibrating-wire 15 has a stretch section 25.

The described hole that is communicated with scavenging duct 17 26 is micro-hole, and baroport 16 is 15～25 with the diameter ratio of micro-hole 26.Scavenging duct 17 is connected between high pressure clean air pipe 28 and the micro-hole 26, and stop valve 9 is connected on to be forced between scavenging duct 18 and the high pressure clean air pipe 28.Pressure limiting valve 27 is housed on the pressure tube 16, and the outlet of pressure limiting valve (27) is connected with differential pressure transmitter (4-2,4-3).

The present invention has the following advantages:

Measure flow, the concentration of dust-contained airflow, must guarantee accuracy, the reliability measured.The monitoring system of design is applicable to flow, the concentration on-line monitoring of dust-contained airflow according to the present invention, has adopted to prevent the probe, the hydrostatic measuring point that stop up reliably, and these anti-blocking means do not influence measuring accuracy again simultaneously; Probe adopts high-abrasive material to make, and can guarantee to work long hours in dust-contained airflow; The relation of measured differential pressure signal and air flow rate, dust concentration is stable, and irrelevant with the factor that becomes to grade of the high pressure clean air pressure that adopts, dust, the measuring accuracy height; Owing to do not have restricting element, measured piping system do not increased resistance; It is simple that this device also has equipment, operational reliability height, characteristics such as easy to maintenance.Applied widely, can be used for the piping system of various conveying dust; Measuring equipment is simple, can reduce the investment in the practical application significantly; The operational reliability height, rotation, movable part are not fragile; Do not increase the extra resistance of ducting; The influence that not changed by the dust composition; Measuring accuracy is higher, and the air quantity precision can reach 1%, and the concentration precision can reach in 5%.

Embodiments of the invention are respectively schemed referring to following:

Fig. 1 is measuring principle of measurement system figure

Fig. 2 is the block diagram of measurement mechanism

Fig. 3 is anti-blocking probe schematic diagram

Fig. 4 is a static pressure sniffer schematic diagram

Principle of the present invention is: can prevent that dust from stopping up and the probe of wearing and tearing, its output differential pressure and gas velocity, dust concentration have fixing relation, the resistance of same a certain segment pipe is also relevant with gas velocity and dust concentration, demarcate and mathematical model is set up relation between gas velocity, dust concentration and these pressure difference signals by scene or testing table, thereby become the means of measurement air flow rate and dust concentration.

The present invention proposes a kind of measurement mechanism as shown in Figure 1, 2, mainly comprise with the lower part:

An anti-blocking probe 1 that is used for measuring the dynamic pressure difference of dust-contained airflow, it adopts the high-abrasive material manufacturing, guarantee that probe is not easy to wear in dust-contained airflow, avoided the probe obstruction by adopting clean air to purge, the output of anti-blocking probe be differential pressure signal, be connected to a differential pressure transmitter 4-1 by pressure tube, this differential pressure is relevant with the speed and the concentration of air-flow.

Two hydrostatic measuring points 2 are arranged at a distance of certain distance on tested pipeline, are used for measuring the resistance and the interior static pressure of pipeline of this segment pipe, and the hydrostatic measuring point of employing can prevent to stop up through particular design; The static pressure of two static pressure measurement device outputs forms a differential pressure, and this differential pressure promptly is the resistance of measured pipeline section, is connected on the differential pressure transmitter by pressure tube.The static pressure of one of them static pressure measurement device is sent into another differential pressure transmitter.The differential pressure of two static pressure measurement device outputs is relevant with the drag characteristic of pipeline and gas velocity, concentration in the pipeline.The method that this static pressure sniffer 2 has taked clean air to purge and vibrate has prevented that the static pressure sniffer from stopping up.

Three differential pressure transmitters 4 are converted to current signal with static pressure in probe dynamic pressure difference and the resistance of ducting and the pipeline and deliver to data acquisition board 5;

A thermopair 3 that is used for temperature in the measuring channel, the voltage signal that thermocouple measurement obtains is also delivered to data acquisition board 5; For being electrically connected, data such as air-flow static pressure in gas flow temperature, the pipeline in anti-blocking probe dynamic pressure, the resistance of ducting, the pipeline are converted to digital signal and are sent to computing machine by signal cable between data acquisition board and differential pressure transmitter and the thermopair;

Computing machine (6), utilize air-flow dynamic pressure that probe measurement obtains, the resistance of ducting that hydrostatic measuring point measures and the flow of dust-contained airflow, the relation between the concentration, all measurement data are calculated, obtain flow, the concentration of air-flow, and has a real-time display result, the query history record, multiple function such as flux cumulating also can increase new function as required at any time.

In the present embodiment, described probe 1 is a kind of anti-blocking resistant wear probe, as shown in Figure 3, described device comprises probe arm 7, differential pressure transmitter 4-1, two probe arms 1 and forms the dynamic pressure probe together, the end of stretching in the dust-contained airflow pipeline is made into wedge shape, a probe arm is met to dust-contained airflow, another is air-flow dorsad, the afterbody of two probe arms 1 stretches in the baffle-box and is communicated with baffle-box 8, have static pressure tapping 13 two probe arm 1 Shens to the end of dust-contained airflow, be connected with differential pressure transmitter 4-1 respectively by pressure tube 12.

The principle of this anti-blocking resistant wear probe is to adopt the differential static pressure of the high pressure clean air relevant with tested air-flow dynamic pressure to replace the dynamic pressure of conventional probe, thus the shortcoming of easy obstruction when having avoided conventional probe to measure dust-contained airflow, and this method is referred to as the differential pressure method of substitution.

Proposed a kind of probe that is used for the dust-contained airflow flow measurement that adopts differential pressure method of substitution design, solved the problem of pressure tube obstruction, distorted signals well, mainly comprised with the lower part:

Two probe arms 1, its geometric condition is identical, and import and export resistance coefficient, coefficient of frictional resistance equate that two arms of probe are formed the dynamic pressure probe, meet a total head of measuring air-flow to air-flow, dorsad the back pressure of air-flow measurement air-flow;

The probe afterbody is provided with baffle-box, and pressure enters in the baffle-box through high pressure clean air pipe far above the high pressure clean air of air-flow total head in the tested pipeline, enters two arms of probe again with identical pressure, sprays in the dust-contained airflow continuously through the probe arm;

Head at two arms of probe is respectively equipped with static pressure tapping 13, respond to the static pressure of high pressure clean air herein, adopt pressure tube 12 that the differential pressure of static pressure tapping is caused differential pressure transmitter 13, this differential pressure is relevant in the dynamic pressure of locality with tested dust-contained airflow, can calculate the dust-contained airflow flow through demarcating the back by this differential pressure;

Hydrostatic measuring point 2 is a kind of static pressure measurement devices with multiple clogging-preventing measures, as shown in Figure 4.On the pipeline wall, have baroport 16, buffer container 14 is housed outside baroport; Be furnished with a vibrating-wire 15 in the buffer container 14, these vibrating-wire 15 1 ends are fixed on the top of buffer container 14 by connector 22, the bell 23 that the other end stretches out the buffer container lower end enters the baroport 16 on the pipeline wall, its effect is that the vibration in tube road itself will be glued near the dust that amasss baroport 16 and be hit, just in case owing to high pressure clean air circuit failure is stopped transport and vibrating-wire 15 removals can be handled when causing in the buffer container 14 a large amount of accumulated powder, for the ease of the installation and the location thereof of vibrating-wire 15, orienting lug 24 is housed in buffer container 14 bottoms; Micro-hole 20, through hole 19,21 are arranged at the top of buffer container 14, pressure tube 30 communicates with through hole 19, in the middle of the pressure tube 30 pressure limiting valve 27 is housed, prevents when baroport 16 from stopping up that the pressure in the buffer container 14 is excessive and damage pressure unit or the tensimeter that connects later; Force scavenging duct 18 two ends to communicate with high pressure clean air pipe 28 and the through hole 21 that cushions on the container 14 respectively, stop valve 29 is equipped with in the centre, and when normally moving, this valve closing opens it when needs purge to purging in the buffer container 14; One end of scavenging duct 17 is communicated with micro-hole 20 on the buffer container 14, and the other end is connected with high pressure clean air pipe 28, and a spot of high pressure clean air can enter in the buffer container 14 by micro-hole 20; On the high pressure clean air pipe 28 filtrator 26 is housed, with the impurity in the high pressure clean air (oil, water, solid particle etc.) filtering, in order to avoid stop up micro-hole 20.

General static pressure measurement device is not provided with scavenging duct 17, because buffer container 14 links to each other with pipe interior by baroport 16, so the pressure in the buffer container 14 equal the static pressure in the pipeline, and the pressure signal that pressure tube 30 is drawn also equals the interior static pressure of pipeline.In this device, pressure enters in the buffer container 14 by micro-hole 20 far above the high pressure clean air of static pressure in the pipeline, but because the diameter of micro-hole 20 is very little, resistance is very big, therefore the high pressure clean air amount that enters buffer container is also little, and these high pressure clean airs enter in the pipeline through relatively large baroport 16.Because flowing of this a small amount of high pressure clean air makes dust be difficult to enter in the baroport, the baroport place is difficult for accumulated powder; When baroport place contingency had accumulated powder, at first the bump of vibrating-wire can hit it fall, and perhaps because accumulated powder causes the baroport diameter to reduce, resistance increases, and the pressure in the buffer container raises, and accumulated powder is extruded baroport.So just guaranteed that baroport can not stop up.

Thermopair 3, differential pressure transmitter 4, data acquisition board 5, computing machine 6 are the commercially available prod, and thermopair adopts the triumphant dress thermopair of K type, and differential pressure transmitter is a Setra C264 type, and data acquisition board is an IMP 1C type, and computing machine is the compatible industrial computer of IBM.

The course of work of this method is as follows:

The method that adopts the probe dynamic pressure and the resistance of ducting to cooperate according to demarcating and the probe dynamic pressure that Theoretical Calculation obtains and the relation of the resistance of ducting and gas velocity and dust concentration, is obtained flow and concentration.

The hydrostatic measuring point that probe and measuring channel resistance are used all has clogging-preventing measures, prevents to stop up pressure port in dust-contained airflow, causes and measures failure; As the abrasionproof measure, probe is made of high-abrasive material, avoids the probe wearing and tearing to cause excessive measuring error or probe to grind away and can't normally measure.

According to the computing method of routine, probe differential pressure, the resistance of ducting and the gas velocity that measures and the pass of dust concentration are: $\mathrm{\Δ}{P}_1=\frac{1}{2k_{\mathrm{kb}}^2}\mathrm{\ρ}{w}^2(1+k_{\mathrm{\μ}}\×\mathrm{\μ})---\left(1\right)$ $\mathrm{\Δ}{P}_2=\frac{1}{2}\mathrm{\ρ}{w}^2({\mathrm{\λ}}_{\mathrm{\μ}}\frac{L}{D}+{\mathrm{\ξ}}_{\mathrm{\μ}})---\left(2\right)$

Wherein:

k _KbFor the probe calibration coefficient, draw by rating test.Scaling method is: employing standard survey wind element---pitot tube is according to the average dynamic pressure Δ of the air-flow p in the uniform cross section method measuring channel _d, the differential pressure Δ p of the pipeline of usefulness probe measurement simultaneously inner control point ₀, calculate the flow calibration coefficient: $k_{\mathrm{kb}}=\sqrt{\frac{\mathrm{\Δ}{p}_d}{\mathrm{\Δ}{p}_0}}$

k _μBe the concentration and probe concentration correction factor;

The local current density of ρ, kg/m ³, can be by atmospheric pressure p _a(Pa), static pressure p _s(Pa) and temperature t (℃) calculate: $\mathrm{\ρ}=1.293\×\frac{273}{273+t}\×\frac{p_a+p_s}{101325}---\mathrm{kg}/m^3$ W is a gas velocity, m/s; μ is a dust concentration, kg/kg; λ _μCoefficient of frictional resistance during for the band powder: λ _μ=λ ₀(1+k _λ* μ) (4) k _λBe frictional resistance concentration correction coefficient; λ ₀Coefficient of frictional resistance during for pure air;

L is a measuring section length, m; D is the measuring channel diameter, m;

Coefficient of shock resistance when ξ μ is the band powder: ξ _μ=ξ ₀(1+k _ξ* μ) (5) k _ξBe shock resistance concentration correction coefficient; ξ ₀Coefficient of shock resistance during for pure air. $\mathrm{\Δ}{P}_2=\frac{1}{2}\mathrm{\ρ}{w}^2({\mathrm{\λ}}_{\mathrm{\μ}}\frac{L}{D}+{\mathrm{\ξ}}_{\mathrm{\μ}})=\frac{1}{2}\mathrm{\ρ}{w}^2\[{\mathrm{\λ}}_0\frac{L}{D}(1+k_{\mathrm{\λ}}\×\mathrm{\μ})+{\mathrm{\ξ}}_0(1+k_{\mathrm{\ξ}}\×\mathrm{\μ})\]$ $=\frac{1}{2}\mathrm{\ρ}{w}^2\[({\mathrm{\λ}}_0\frac{L}{d}+{\mathrm{\ξ}}_0)+(k_{\mathrm{\λ}}{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0\×k_{\mathrm{\ξ}})\×\mathrm{\μ}\]---\left(6\right)$ Compare with the resistance of ducting under the pure air: $\frac{\mathrm{\Δ}{P}_2}{\mathrm{\Δ}{P}_2^0}=\frac{\frac{1}{2}\mathrm{\ρ}{w}^2\[({\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0)+(k_{\mathrm{\λ}}{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0\×k_{\mathrm{\ξ}})\×\mathrm{\μ}\]}{\frac{1}{2}\mathrm{\ρ}{w}^2({\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0)}=1+\frac{k_{\mathrm{\λ}}{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0{k}_{\mathrm{\ξ}}}{{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0}\×\mathrm{\μ}---\left(7\right)$

In the formula (6), the coefficient of concentration μ is only relevant with the structure of measuring channel, and this coefficient is defined as the concentration correction coefficient k of the resistance of ducting, under the resistance of ducting under the band powdery attitude and the pure air during identical speed the ratio of the resistance of ducting be defined as resistance ratios R, then: R=1+k _μ(8) wherein: $R=\frac{\mathrm{\Δ}{P}_2}{\mathrm{\Δ}{P}_2^0}---\left(9\right)$ $k=\frac{k_{\mathrm{\λ}}{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0{k}_{\mathrm{\ξ}}}{{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0}---\left(10\right)$

In above computing formula, for specific pipeline and measurement point, can think that except speed and concentration, other parameter is known number, measure two differential pressures after, speed and concentration can be obtained.Solution procedure can adopt iteration technique to carry out, and at first obtains gas velocity w under the initial concentration according to the probe differential pressure by formula 1 ₁, measure the resistance of pipeline section when calculating the pure gas state under this speed according to the drag characteristic of pipeline $\mathrm{\Δ}{p}_2^0,$ Obtain resistance ratios $R=\mathrm{\Δ}{p}_2/\mathrm{\Δ}{p}_2^0,$ Can draw concentration μ according to formula 8 ₁, again with μ ₁Repeat said process as initial concentration, the speed of obtaining up to twice adjacent calculation, the deviation of concentration value are enough little, promptly think to have obtained speed, concentration value accurately.

Claims (9)

1. the on-line monitoring method of dust-contained airflow flow and concentration, its step is as follows:

1) under the pure gas state, adopt conventional criteria survey the wind element one by one pitot tube according to the average dynamic pressure △ of the air-flow p in the uniform cross section method measuring channel _d, the differential pressure △ p of the pipeline of usefulness probe measurement simultaneously inner control point ₀, probe (1) is demarcated, obtain the flow calibration coefficient k of probe _KbFor: $k_{\mathrm{kb}}=\sqrt{\frac{\mathrm{\Δ}{P}_d}{\mathrm{\Δ}{P}_0}}$

2) under the pure gas state, measure the resistance of each segment pipe of tested pipeline section, calculate the coefficient of frictional resistance λ of tested pipeline section according to resistance of ducting characteristic formula ₀Coefficient of shock resistance ξ with restricting element in the pipeline section and elbow ₀

3) choose according to pipe characteristic and contain frictional resistance correction factor k under the powdery attitude _λWith shock resistance correction factor k _ξ, calculate the concentration correction coefficient k of the resistance of ducting by following formula: $k=\frac{k_{\mathrm{\λ}}{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0{k}_{\mathrm{\ξ}}}{{\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0}$

4) the flow calibration coefficient k of probe _Kb, the resistance of ducting the concentration correction coefficient k all be preset in the measurement calculation procedure of computing machine (6), measuring probe (1) is inserted in the pipeline of band dust, meet a total head of measuring air-flow to air-flow, air-flow back pressure of measuring air-flow obtains exporting differential pressure △ p dorsad ₁Resistance of ducting differential pressure △ p with two hydrostatic measuring points (2) output ₂, and obtain static pressure p in the pipeline by hydrostatic measuring point (2-2) _s, obtain the interior temperature f of pipeline by measuring point (3);

5) by choosing atmospheric pressure P _a, according to the static pressure P that measures _sWith temperature t be by the current density p that the current density formula calculates in the pipeline: $\mathrm{\ρ}=1.293\×\frac{273}{273+t}\×\frac{P_a+P_s}{101325}---\mathrm{kg}/m^3$

6) by probe differential pressure △ p ₁By probe differential pressure formula $\mathrm{\Δ}{P}_1=\frac{1}{2k_{\mathrm{kb}}^2}\mathrm{\ρ}{w}^2(1+k_{\mathrm{\μ}}\×\mathrm{\μ})$ Calculate concentration and be 0 o'clock wind speed w ₁, k wherein _μBe probe differential pressure concentration correction coefficient: $w_1=k_{\mathrm{kb}}\sqrt{\frac{2\mathrm{\Δ}{p}_1}{\mathrm{\ρ}(1+k_{\mathrm{\μ}}\×\mathrm{\μ})}}$

7) calculating concentration according to the drag characteristic of pipeline by resistance of ducting characteristic formula is 0 o'clock, is w at wind speed ₁Situation under the resistance of ducting differential pressure during pure gas state $\mathrm{\Δ}{P}_2^0$ For: $\mathrm{\Δ}{P}_2^0=\frac{1}{2}\mathrm{\ρ}{w}^2({\mathrm{\λ}}_0\frac{L}{D}+{\mathrm{\ξ}}_0)$ Resistance ratios then $R=\mathrm{\Δ}{P}_2/{\mathrm{\ΔP}}_2^0,$ Calculate concentration μ by formula R=1+k μ ₁For: ${\mathrm{\μ}}_1=\frac{R-1}{k}$

8) with the concentration value μ that obtains ₁Substitution probe differential pressure type $\mathrm{\Δ}{P}_1=\frac{1}{2}{k}_{\mathrm{kb}}\mathrm{\ρ}{w}^2(1+k_{\mathrm{\μ}}\×\mathrm{\μ}),$ Obtain the gas velocity w under this concentration ₂, the wind speed w that uses this step to obtain ₂Repeat aforementioned calculation, obtained the concentration value μ that calculates for the second time ₂, with the speed w that obtains ₂, concentration value μ ₂Computing velocity w with last time ₁, concentration value μ ₁Relatively, if error less than 0.5%, computing machine thinks and obtained gas velocity and dust concentration accurately, otherwise repeating step 7,8 until the speed that calculates for twice, concentration error less than 0.5%;

9) show measurement result in real time by the on-Line Monitoring Program in the computing machine (6), and can pass through this program inquiring historical record.

2. device that designs according to said method, comprise probe (1), static pressure sniffer (2), temperature detection instrument (3), differential pressure transmitter, data acquisition board (5), computing machine (6), the anti-blocking probe (1) that it is characterized in that being used for measuring the ash-laden gas flow differential pressure is connected with differential pressure transmitter (4-1), 2 hydrostatic measuring point (2-1 that the segment distance of being separated by on pipeline is arranged, 2-2) be connected with differential pressure transmitter (4-2), getting static pressure signal on hydrostatic measuring point (2-2) is connected with differential pressure transmitter (4-3), probe dynamic pressure difference and differential static pressure can be converted to the differential pressure transmitter (4-1 of current signal, 4-2,4-3) be electrically connected with data acquisition board (5), the output of data acquisition board (5) is connected with computing machine (6) by data bus.

3. device according to claim 2, it is characterized in that described anti-blocking probe (1) comprises probe arm (7), buffer container (8), high pressure clean air pipeline (11), pressure tube (12), two probe arms (7) are formed the dynamic pressure probe, the end of stretching in the dust-contained airflow pipeline is made into wedge shape, a probe arm is met to dust-contained airflow, another is air-flow dorsad, the afterbody of two probe arms (7) is communicated with baffle-box (8), the end of stretching to dust-contained airflow at two probe arms (7) has static pressure tapping (13), is connected with differential pressure transmitter (9) respectively by pressure tube (12).

4. device according to claim 3 is characterized in that described high pressure clean air enters in the buffer container through high pressure clean air pipeline (11), sprays in the dust-contained airflow through the probe arm again.

5. device according to claim 2, it is characterized in that described static pressure sniffer (2), comprise a buffer container (14), one vibrating-wire (15) is arranged in the buffer container (14), described vibrating-wire (15) stretches out buffer container (14) and enters baroport (16) on the pipeline wall, has on the top of buffer container (14) and pressure tube (30), scavenging duct (17), the hole (19,20,21) of forcing scavenging duct (18) to be communicated with.

6. device according to claim 5, it is characterized in that described vibrating-wire (15) one ends are fixed on the top of buffer container (14) by connector (22), the bell (23) that the other end stretches out the buffer container lower end enters the baroport (16) on the pipeline wall, the orienting lug (24) of one definite vibrating-wire (15) direction is arranged on bell (23) internal face, and described vibrating-wire (15) has a stretch section (25).

7. device according to claim 5 is characterized in that the described hole (20) that is communicated with scavenging duct (17) is micro-hole, and baroport (16) is 15～25 with the diameter ratio of micro-hole (20).

8. device according to claim 5 is characterized in that being equipped with on the pressure tube (30) pressure limiting valve (27), and the outlet of pressure limiting valve (27) is connected with differential pressure transmitter (4-2,4-3).

9. device according to claim 5, it is characterized in that scavenging duct (17) is connected between high pressure clean air pipe (28) and the micro-hole (20), stop valve (29) is connected on to be forced between scavenging duct (18) and the high pressure clean air pipe (28) filtrator (26) to be housed on the high pressure clean air pipeline.

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