CN103925951B - Method for monitoring air quantity passing through fan controlled by frequency converter on line - Google Patents

Abstract

The invention discloses a method for monitoring the air quantity of a fan controlled by a frequency converter on line through air quantity, which belongs to the field of air quantity measurement. Compared with the existing measuring method, the method only needs the frequency and the power measured by the frequency converter in the measuring process, does not need various sensors such as wind speed and wind volume, can effectively avoid the influence of severe measuring environment on the measuring result, and can be suitable for online measurement of the wind volume under various severe conditions including a mining dust removal fan.

Description

By the blower fan of Frequency Converter Control by air quantity on-line monitoring method

Technical field

The invention belongs to air measuring field, particularly relate to by the blower fan of Frequency Converter Control by air quantity on-line monitoring side Method.

Background technology

Air measuring is the physical quantity of the required monitoring of industrial numerous occasion, based on different measuring principles, the most domestic There are outward substantial amounts of wind speed, the property right of air flow sensor and corresponding measuring method, measurement apparatus based on principle of uniformity and method Substantially there are identical pluses and minuses.Typical air measuring method has following several:

Method one: quiet differential pressure flowmeter:

According to bernoulli equation and the principle of continuity: after fluid flows through throttling arrangement, static pressure can reduce, its decreasing value is more Greatly, the flow flowing through throttling arrangement is the biggest.Before and after differential pressure flowmeter i.e. utilizes this principle by measuring throttling element Static pressure difference calculates the size of fluid flow.

The method, due to its high stability and high precision, can be applied relatively broad in industry field, but based on this principle Effusion meter in by the existence of throttling element, fluid, after this device, has bigger permanent compression loss, and energy loss is big, because of This is not first-selected flow-measuring method in a lot of occasions.

Method two: velocity-averaging tube flow sensor:

Velocity-averaging tube flow sensor is a kind of flow transducer based on pitot tube measuring principle, by inserting in pipeline Pressure pipe obtains static pressure and the dynamic pressure of fluid, thus obtains fluid wind speed, calculated flow rate.

The method is measured flow and has the feature such as simple in construction, little, the low cost of permanent crushing, but is based on this principle and obtains Sensor requirements before and after have a straight length (generally 7 25 times of internal diameter of the pipeline) of certain length, and dust in fluid, Water smoke etc. not only can affect certainty of measurement, and can block pressure port when using for a long time.Therefore effusion meter based on this principle Often volume is big, and maintenance is big.

Method three: thermal mass flow meter:

The method is to utilize the pass between energy and the fluid mass needed for fluid temperature (F.T.) rises a certain value when adding hot fluid The mass flow of fluid is measured by system.Generally having two heat-resistant element in gasmetry section, one of them is used for temperature detection, separately One is used for heating.Temperature-sensing element be used for detected gas temperature, heater then by change electric current keep its temperature with The constant temperature difference of tested gas temperature.If after gas flow rate change, then the electric current of the constant temperature difference of thermal resistance is kept also to change, Change and the change obtaining gas mass flow according to supply electric current.

Effusion meter based on the method, if after the notable change containing water smoke and dust concentration in gas, can be because affecting thermal conductance Rate value, and dust can affect its measured value at the deposition dirt layer of tube wall, and therefore for making that dust and water smoke change greatly Should not apply with place, even if ignoring the change that dust and water smoke are equivalent to thermal conductivity, owing to the fast deposition of dust also can add The heavily maintenance workload of this effusion meter.

In sum, the method for current air measuring realizes based on wind speed, air flow sensor mostly, and these sensings Device is the most sensitive to severe measurement environment (such as aqueous, dust-laden), and Part Methods also need to when application longer before , when therefore using above measuring method under conditions of measuring bad environments, often there is certainty of measurement the highest in rear straight length, Maintenance is big, volume is excessive, be difficult to the shortcomings such as installation.

Summary of the invention

Because the drawbacks described above of prior art, the technical problem to be solved is to provide a kind of application-oriented existing , it is not necessary to straight length, to the adverse circumstances insensitive blower fan On-line Measuring Method by air quantity.

For achieving the above object, the invention provides a kind of by the blower fan of Frequency Converter Control by air quantity on-line monitoring side Method, comprises the following steps:

Step one, determining N number of windage point, determine M blower fan frequency, described M is positive integer and more than or equal to 2, and described N is Positive integer；Set blower fan frequency sets as F, $F=\left(\begin{array}{c}{f}_1\\ f_2\\ .\\ .\\ .\\ f_M\end{array}\right),$ This frequency band takes at least 2 frequency values；

For i-th windage point, measure and obtain at M power of fan corresponding to each blower fan frequency, obtain power of fan collection Close Pi；Measure and obtain in M fan delivery corresponding to each blower fan frequency, obtain fan delivery set Qi, 1≤i≤N；Described $P_i=\left(\begin{array}{c}{P}_{i1}\\ P_{i2}\\ .\\ .\\ .\\ P_{\mathrm{iM}}\end{array}\right),$ Described $Q_i=\left(\begin{array}{c}{Q}_{i1}\\ Q_{i2}\\ .\\ .\\ .\\ Q_{\mathrm{iM}}\end{array}\right);$

Blower fan frequency, power of fan and fan delivery that step 2, utilization are measured are calculated basic data；

For i-th windage point, calculate $B_i^T={\left(F_P^T{F}_P\right)}^{-1}{F}_P^T{P}_i$ Obtain the first matrix $B_i^T=\left(\begin{array}{c}{b}_{i0}\\ b_{i1}\\ .\\ .\\ .\\ b_{\mathrm{ir}}\end{array}\right);$ Described F_P For power designs matrix, described P_iFor power matrix；Described i is the positive integer less than or equal to N；

DescribedDescribed f_MFrequency for blower fan；Described 2≤r≤M；

For i-th windage point, calculateObtain the second matrix $C_i^T=\left(\begin{array}{c}{c}_{i0}\\ c_{i1}\\ .\\ .\\ .\\ c_{\mathrm{is}}\end{array}\right);$ Described F_QFor air quantity design matrix；

DescribedDescribed 2≤s≤M；

Set basic data as A_xy, calculate

Obtain basic data A_xy, described N is the most whole Number；X is integer and 1≤x≤N, and y is integer and 0≤y≤r+s；

Step 3, the running frequency measuring current blower fan and operation power；

Step 4, the running frequency setting current blower fan are P as f, the operation power of current blower fan₀, the current wind of blower fan Amount is Q_z；Set blower fan to specific power as P_z, set the contrast air quantity of blower fan as Q_v；

Calculate P_z=A_i1+A_i2f+......+A_irf^r-1Obtain P_z, 1≤z≤N；

Calculate Q_v=A_i(r+1)+A_i(r+2)f+......+A_i(r+s)f^s-1Obtain Q_v, 1≤v≤N；

Step 5, judge whether P₀＞ P_N；Work as P₀＞ P_NTime, the current air quantity Q of blower fan_z=Q_N；Work as P₀≤P_NTime, perform step Rapid six；

Step 6, judge whether P₀＜ P₁；Work as P₀＜ P₁Time, the current air quantity Q of blower fan_z=Q₁；Work as P₀≥P₁Time, perform step Rapid seven；

Step 7, set g as reduced parameter；1≤g≤N-1, determines satisfied (P₀-P_g)×(P₀-P_g+1The g of)≤0；Calculate $Q_z=\frac{Q_{g+1}-Q_g}{P_{g+1}-P_g}\×(P_0-P_g)+Q_g$ Obtain the current air quantity Q of blower fan_z。

Using above technical scheme, the present invention need not sensor outside converter, decreases line arrangement and sensing The trouble that device mounting condition limits, can be applicable to simultaneously all by the blower fan of Frequency Converter Control as the industry spot wind of power The measurement of amount, and without straight length, it is not necessary to consider whether gas contains other composition such as dust, water smoke.And the present invention makes Without carrying out the maintenances such as cleaning during with, reduce working service amount.

It is also preferred that the left described M blower fan frequency of acquisition, M power of fan and M the fan delivery measured is come by the following method Obtain:

A1, determine the main frequency section of actual condition fan operation, this frequency band takes at least 2 frequency values；

A2, windage when regulating fan operation by the method using paster to increase resistance at blower fan air intake, in each windage The power of blower fan and air quantity when being separately recorded in the frequency that step one determines.

The invention has the beneficial effects as follows: the present invention compares relative to existing air quantity testing method and mainly has the advantage that

1. need not sensor, decrease line arrangement, sensor mounting condition restriction etc. bothers.

2. can be applicable to all by the blower fan of Frequency Converter Control as the measurement of the industry spot air quantity of power, and need not Consider whether gas contains other composition such as dust, water smoke.

3., even if contain other composition such as dust, water smoke in gas, owing to there is no sensor, will not stick due to dust The factor such as attached and have influence on the precision of sensor.The most in use without carrying out the maintenances such as cleaning, it is not necessary to safeguard, save Maintenance cost.

4. the present invention is without straight length, is particularly suitable for the site of deployment of limited space.

The present invention can carry out air measuring to the industry spot that various measuring conditions are severe, solves by Frequency Converter Control The blower fan problem that air measuring precision is low when various severe measurement environment, maintenance is big.The present invention is workable, measures Accurately, using effect is good.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of the embodiment of the invention.

Detailed description of the invention

The invention will be further described with embodiment below in conjunction with the accompanying drawings:

Passed through air quantity on-line monitoring method as it is shown in figure 1, a kind of by the blower fan of Frequency Converter Control, comprise the following steps:

Step one, determining N number of windage point, determine M blower fan frequency, described M is positive integer and more than or equal to 2, and described N is Positive integer；Set blower fan frequency sets as F, $F=\left(\begin{array}{c}{f}_1\\ f_2\\ .\\ .\\ .\\ f_M\end{array}\right),$ This frequency band takes at least 2 frequency values；

For i-th windage point, measure and obtain at M power of fan corresponding to each blower fan frequency, obtain power of fan collection Close Pi；Measure and obtain in M fan delivery corresponding to each blower fan frequency, obtain fan delivery set Qi, 1≤i≤N；Described $P_i=\left(\begin{array}{c}{P}_{i1}\\ P_{i2}\\ .\\ .\\ .\\ P_{\mathrm{iM}}\end{array}\right),$ Described $Q_i=\left(\begin{array}{c}{Q}_{i1}\\ Q_{i2}\\ .\\ .\\ .\\ Q_{\mathrm{iM}}\end{array}\right).$

Blower fan frequency, power of fan and fan delivery that step 2, utilization are measured are calculated basic data；

For i-th windage point, calculate $B_i^T={\left(F_P^T{F}_P\right)}^{-1}{F}_P^T{P}_i$ Obtain the first matrix $B_i^T=\left(\begin{array}{c}{b}_{i0}\\ b_{i1}\\ .\\ .\\ .\\ b_{\mathrm{ir}}\end{array}\right);$ Described F_PFor power designs matrix, described P_iFor power matrix；Described i is the positive integer less than or equal to N；

DescribedDescribed f_MFrequency for blower fan；Described 2≤r≤M；

For i-th windage point, calculate $C_i^T={\left(F_Q^T{F}_Q\right)}^{-1}{F}_Q^T{Q}_i$ Obtain the second matrix $C_i^T=\left(\begin{array}{c}{c}_{i0}\\ c_{i1}\\ .\\ .\\ .\\ c_{\mathrm{is}}\end{array}\right);$ Institute State F_QFor air quantity design matrix；

DescribedDescribed 2≤s≤M；

Set basic data as A_xy, calculate

Obtain basic data A_xy, described N is the most whole Number；X is integer and 1≤x≤N, and y is integer and 0≤y≤r+s；

Step 3, the running frequency measuring current blower fan and operation power；

Step 4, the running frequency setting current blower fan are P as f, the operation power of current blower fan₀, the current wind of blower fan Amount is Q_z；Set blower fan to specific power as P_z, set the contrast air quantity of blower fan as Q_v；

Calculate P_z=A_i1+A_i2f+......+A_irf^r-1Obtain P_z, 1≤z≤N；

Calculate Q_v=A_i(r+1)+A_i(r+2)f+......+A_i(r+s)f^s-1Obtain Q_v, 1≤v≤N；

Step 5, judge whether P₀＞ P_N；Work as P₀＞ P_NTime, the current air quantity Q of blower fan_z=Q_N；Work as P₀≤P_NTime, perform step Rapid six；

Step 6, judge whether P₀＜ P₁；Work as P₀＜ P₁Time, the current air quantity Q of blower fan_z=Q₁；Work as P₀≥P₁Time, perform step Rapid seven；

Step 7, set g as reduced parameter；1≤g≤N-1, determines satisfied (P₀-P_g)×(P₀-P_g+1The g of)≤0；Calculate $Q_z=\frac{Q_{g+1}-Q_g}{P_{g+1}-P_g}\×(P_0-P_g)+Q_g$ Obtain the current air quantity Q of blower fan_z。

Described M blower fan frequency of acquisition, M power of fan and M the fan delivery measured obtains by the following method:

A1, determine the main frequency section of actual condition fan operation, this frequency band takes at least 2 frequency values；

A2, windage when regulating fan operation by the method using paster to increase resistance at blower fan air intake, in each windage The power of blower fan and air quantity when being separately recorded in the frequency that step one determines.Certainly, the present invention can also use additive method Windage during regulation fan operation, the such as method in the employing throttling of blower fan air intake regulates windage during fan operation, its All should be within the scope of the present invention.

Described measurement obtains M blower fan frequency and M power of fan according to the reading change of the MT159 mining dust catcher universal standard Frequently device obtains, and calculates according to the MT159 mining dust catcher universal standard described in the measurement of fan delivery.

In order to further illustrate the present invention, under the conditions of present 6 kinds of different windages, choose 5 frequencies (i.e. taking M=5) and record Power of fan and fan delivery data such as table 1.

Data list tested by table 1

The present embodiment takes N=6, r=3, s=2, can obtain, and the coefficient " B1 " of windage serial number 1 is: [13.725 ,- 1.0278,0.02559]；Coefficient " C1 " during windage serial number 1 is: [3.7,7.91].A1=[13.725 ,-1.0278, 0.02559,3.7,7.91].By that analogy, other each windage uses identical calculations method to obtain basic data as shown in table 2 Table.

Table 2 base data table

When by test above blower fan be used for certain different areas of activity time, on converter, the running frequency of blower fan of display is 46.93Hz, frequency be power of fan during 46.93Hz and fan delivery as shown in table 3.

Table 3 frequency is power during 46.93Hz and air quantity

And under this frequency, on converter display power be 22.686KW, it is known that boundary between windage 1 and windage 2, because of This carries out linear interpolation according to windage 1 with the data of windage 2 and can obtain air quantity corresponding to this power:

$Q_z=\frac{Q_{g+1}-Q_g}{P_{g+1}-P_g}\×(P_0-P_g)+Q_g=\frac{398.84-374.91}{22.84-21.85}\×(22.686-21.85)+374.91=395.12m^3/\min .$

During the present embodiment test, windage is from big to small.And actual test, coefficient calculations and air quantity measure sequence in real time Can arrange from small to large by windage.

The preferred embodiment of the present invention described in detail above.Should be appreciated that those of ordinary skill in the art without Need creative work just can make many modifications and variations according to the design of the present invention.Therefore, all technology in the art Personnel are available by logical analysis, reasoning, or a limited experiment the most on the basis of existing technology Technical scheme, all should be in the protection domain being defined in the patent claims.

Claims (2)

1. one kind is passed through air quantity on-line monitoring method by the blower fan of Frequency Converter Control, it is characterised in that comprise the following steps:

Step one, determining N number of windage point, each windage point determines M blower fan frequency, and described M is positive integer and more than or equal to 2, Described N is positive integer；Set the blower fan frequency sets of each windage point as F,This frequency band takes at least 2 Frequency values；

For i-th windage point, measure and obtain at M power of fan corresponding to each blower fan frequency, obtain power of fan set Pi； Measure and obtain in M fan delivery corresponding to each blower fan frequency, obtain fan delivery set Qi, 1≤i≤N；DescribedDescribed

Blower fan frequency, power of fan and fan delivery that step 2, utilization are measured are calculated basic data；

For i-th windage point, calculateObtain the first matrix Described F_PFor merit Rate design matrix, described P_iFor power matrix；Described i is the positive integer less than or equal to N；

DescribedDescribed f_MFrequency for blower fan；Described 2≤r≤M；

For i-th windage point, calculateObtain the second matrix Described F_Q For air quantity design matrix；

DescribedDescribed 2≤s≤M；

Set basic data as A_xy, calculate

Obtain basic data A_xy, described N is positive integer；X is Integer and 1≤x≤N, y is integer and 0≤y≤r+s；

Step 3, the running frequency measuring current blower fan and operation power；

Step 4, the running frequency setting current blower fan are P as f, the operation power of current blower fan₀, the current air quantity of blower fan is Q_z；Set blower fan to specific power as P_z, set the contrast air quantity of blower fan as Q_v；

Calculate P_z=A_i1+A_i2f+......+A_irf^r-1Obtain P_z, 1≤z≤N；

Calculate Q_v=A_i(r+1)+A_i(r+2)f+......+A_i(r+s)f^s-1Obtain Q_v, 1≤v≤N；

Step 5, judge whether P₀＞ P_N；Work as P₀＞ P_NTime, the current air quantity Q of blower fan_z=Q_N；Work as P₀≤P_NTime, perform step 6；

Step 6, judge whether P₀＜ P₁；Work as P₀＜ P₁Time, the current air quantity Q of blower fan_z=Q₁；Work as P₀≥P₁Time, perform step 7；

Step 7, set g as reduced parameter；1≤g≤N-1, determines satisfied (P₀-P_g)×(P₀-P_g+1The g of)≤0；CalculateObtain the current air quantity Q of blower fan_z。

2. passed through air quantity on-line monitoring method by the blower fan of Frequency Converter Control as claimed in claim 1, it is characterized in that: described survey Amount obtains M blower fan frequency, M power of fan and M fan delivery and obtains by the following method:

A1, determine the main frequency section of actual condition fan operation, this frequency band takes at least 2 frequency values；

A2, windage when regulating fan operation by the method using throttling to increase resistance at blower fan air intake, in each windage respectively The power of record blower fan when the frequency that step one determines and air quantity.