阅读说明：本技术 一种气体涡轮流量计检定的信号检测方法 (Signal detection method for gas turbine flowmeter verification ) 是由 黄智慧 章圣意 肖云巩 杨龙 于 2020-12-11 设计创作，主要内容包括：本发明公开涉及一种气体涡轮流量计检定的信号检测方法,包括标准流量计、调频风机、变频器、检测台、直管段、上位机、涡轮流量计和激光传感器,当上位机启动检定指令,开启的调频风机使气体依次经过直管段、涡轮流量计和标准表,激光传感器的激光射线通过涡轮流量计前端的整流器间隙,并照射在内部叶轮的叶片上,叶轮叶片在气体的推动下稳定旋转,快速切割激光的光线,由此,激光传感器产生与流量成正比的高频脉冲信号,并传送给上位机,进行数据处理和运算,得出流量计各流量点的误差,该新方法可使流量计在无需增加额外高频信号输出结构的基础上,实现流量计的高效检定。(The invention discloses a signal detection method for detecting a gas turbine flowmeter, which comprises a standard flowmeter, a frequency modulation fan, a frequency converter, a detection platform, a straight pipe section, an upper computer, a turbine flowmeter and a laser sensor, when the upper computer starts a verification instruction, the started frequency modulation fan enables gas to sequentially pass through the straight pipe section, the turbine flowmeter and the standard meter, the laser ray of the laser sensor passes through the rectifier gap at the front end of the turbine flowmeter, and irradiates on the blades of the inner impeller, the blades of the impeller stably rotate under the push of gas, quickly cuts the light of laser, therefore, the laser sensor generates a high-frequency pulse signal which is in direct proportion to the flow and transmits the high-frequency pulse signal to the upper computer for data processing and operation to obtain the error of each flow point of the flowmeter, the new method can realize the high-efficiency verification of the flowmeter on the basis of not increasing an additional high-frequency signal output structure.)

1. A signal detection method for detecting a gas turbine flowmeter is characterized by comprising the following steps: the method comprises the following steps:

a standard flow meter for detecting a standard flow volume;

a test stand for mounting a turbine flowmeter to be tested;

the turbine flowmeter is a detected flowmeter and is arranged on the detection platform and is connected with the standard flowmeter in series;

a frequency modulated fan for generating a negative pressure to force the gas through the turbine flow meter and the standard flow meter;

the frequency converter is used for changing the running power of the frequency modulation fan;

the straight pipe section is arranged on the front side of an air inlet of the turbine flowmeter and used for rectifying and guiding air flow;

the laser sensor is arranged on the front side of the air inlet of the straight pipe section, and the laser head faces the inside of the pipe opening of the straight pipe section and is used for measuring the number of high-frequency pulses;

the frequency modulation fan is started to generate negative pressure, so that the air flow sequentially passes through the straight pipe section, the turbine flowmeter and the standard flowmeter, a rectifier in the turbine flowmeter can rectify and accelerate the air flow, the laser sensor emits laser rays to irradiate on blades of an impeller of the turbine flowmeter, when the impeller of the turbine flowmeter rotates, the laser sensor collects high-frequency pulse signals and transmits the high-frequency pulse signals to the upper computer, and the upper computer calculates the test indication errors of all flow points required by the test through the following formula:

in the formula: e₁Relative indication error of the turbine flowmeter,%; v₁Is the cumulative flow rate value, m, of the turbine flowmeter³；V_SCumulative flow value, m, converted to state at flowmeter for standard flowmeter³(ii) a N is the high-frequency pulse number collected and measured by the laser sensor, imp/s; n is impeller blade of turbine flowmeterThe number of (c), (k) is the average meter coefficient (through the total number of revolutions of the impeller or the gear ratio per cubic meter of gas) counted by the turbine meter, (m)³)^-1。

2. A method of signal detection for a gas turbine flow meter verification as claimed in claim 1 wherein: the light emitted by the laser head is parallel to the axial lead of the straight pipe section.

3. A method of signal detection for a gas turbine flowmeter assay as claimed in claim 1 or 2, wherein: the distance between a laser head of the laser sensor and the pipe orifice of the straight pipe section is not less than 5CM, and the length of the straight pipe section is more than 3 times of the nominal diameter of the straight pipe section.

4. A method of signal detection for a gas turbine meter verification according to claim 1, 2 or 3, wherein: the light of the laser sensor passes through the grid-blade gap of the rectifier from the inlet of the turbine flowmeter and reaches the blades of the impeller, and a high-frequency signal is extracted.

Technical Field

The invention relates to the technical field of instrument detection, in particular to a signal detection method for detecting a gas turbine flowmeter.

Background

The gas turbine flowmeter has two types of intelligent type and mechanical type, wherein the mechanical type is that the rotating speed of a turbine is quantitatively reduced through gear transmission and then the working condition is output by a mechanical counterThe structural principle of flow cumulant; in use, in order to further realize temperature and pressure correction and compensation, the volume corrector is often used together, and a low-frequency reed switch module is generally arranged beside a mechanical counter of a gauge head and is used for 0.1m per pulse³、1m³Or 10m³The output form of the pulse equivalent is connected with a volume corrector, and meanwhile, the flow signal of the output module can also be used for verification; however, because the output is low-frequency pulse, according to the detection requirement of the detection regulation, each flow point obviously lengthens when enough pulse is obtained, and particularly, when the small flow point is detected, one complete detection work usually needs more than 1 h; meanwhile, after the flowmeter is calibrated for the first time, error calibration is often needed to adjust the transmission ratio, and the flowmeter needs to be calibrated and confirmed again, so that the whole calibration work consumes too long time and the efficiency is low; the problem of long verification time can be solved by adding a high-frequency module design on the flowmeter body, but the market competitiveness of the flowmeter is greatly influenced and cannot be compensated due to the extra cost of hundreds of yuan added by the high-frequency module.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects of the prior art, the invention provides a signal detection method for detecting a gas turbine flowmeter, which adopts a new method to realize the high-efficiency detection of the flowmeter on the basis of not changing the signal output structure of the flowmeter and not increasing the cost.

The invention discloses a signal detection method for detecting a gas turbine flowmeter, which is characterized by comprising the following steps: the method comprises the following steps:

a standard flow meter for detecting a standard flow volume;

a test stand for mounting a turbine flowmeter to be tested;

the turbine flowmeter is a detected flowmeter and is arranged on the detection platform and is connected with the standard flowmeter in series;

a frequency modulated fan for generating a negative pressure to force the gas through the turbine flow meter and the standard flow meter;

the frequency converter is used for changing the running power of the frequency modulation fan;

the straight pipe section is arranged on the front side of an air inlet of the turbine flowmeter and used for rectifying and guiding air flow;

the laser sensor is arranged on the front side of the air inlet of the straight pipe section, and the laser head faces the inside of the pipe opening of the straight pipe section and is used for measuring the number of high-frequency pulses;

the frequency modulation fan is started to generate negative pressure, so that the air flow sequentially passes through the straight pipe section, the turbine flowmeter and the standard flowmeter, a rectifier in the turbine flowmeter can rectify and accelerate the air flow, the laser sensor emits laser rays to irradiate on blades of an impeller of the turbine flowmeter, when the impeller of the turbine flowmeter rotates, the laser sensor collects high-frequency pulse signals and transmits the high-frequency pulse signals to the upper computer, and the upper computer calculates the test indication errors of all flow points required by the test through the following formula:

in the formula: e₁Relative indication error of the turbine flowmeter,%; v₁Is the cumulative flow rate value, m, of the turbine flowmeter³；V_SCumulative flow value, m, converted to state at flowmeter for standard flowmeter³(ii) a N is the high-frequency pulse number collected and measured by the laser sensor, imp/s; n is the number of impeller blades of the turbine flowmeter, k is the average meter coefficient (through the total number of revolutions of the impeller or the gear ratio per cubic meter of gas) counted by the turbine flowmeter, (m)³)^-1。

The invention further provides that: the light emitted by the laser head is parallel to the axial lead of the straight pipe section.

The invention further provides that: the distance between a laser head of the laser sensor and the pipe orifice of the straight pipe section is not less than 5CM, and the length of the straight pipe section is more than 3 times of the nominal diameter of the straight pipe section.

The invention further provides that: the light of the laser sensor passes through the grid-blade gap of the rectifier from the inlet of the turbine flowmeter and reaches the blades of the impeller, and a high-frequency signal is extracted.

In summary, the invention has the advantages that the gas is uniformly distributed through the rectifier to push the impeller of the turbine flowmeter to rotate, after the flow rate is stable, the rotating speed of the impeller is approximately in direct proportion to the flow rate, because the blades of the impeller of the turbine flowmeter are generally designed to be more than 10, each circle of the impeller is rotated, the laser sensor can collect more than ten pulses, even at the minimum flow point, the general frequency can reach about 50-300, the detection signal greatly shortens the effective time required by the detection, on the basis of not changing the signal output structure of the flowmeter and not increasing the cost, the novel method is adopted to realize the high-efficiency detection of the flowmeter, and the problem of long detection time of the small flow rate is well solved.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a block flow diagram of the present invention;

FIG. 3 is an exploded view of the turbine flowmeter of the present invention;

FIG. 4 is a view of the laser sensor, straight tube section, rectifier, impeller in combination in accordance with the present invention;

fig. 5 is an enlarged view of a portion a of fig. 4.

Detailed Description

The following detailed description of specific embodiments of the invention is provided in conjunction with the accompanying drawings:

V_Sthe value calculation is related to temperature and pressure, and the gas molecular distance changes along with the change of the temperature or the pressure, so the problems of temperature compensation and pressure compensation need to be considered when measuring the flow of the gas, the specific solution of the automatic temperature and pressure compensation belongs to the common knowledge of the technicians in the field, the detailed description is not provided herein, the frequency modulation fan 4 can be a centrifugal fan, and the upper computer can adopt a computer capable of directly sending an operation command.

The invention discloses a signal detection method for detecting a gas turbine flowmeter, which comprises the following steps:

a standard flow meter 1 for detecting a standard flow volume;

a test table 2 for mounting a turbine flowmeter 3 to be tested;

the turbine flowmeter 3 is a flowmeter to be detected, is arranged on the detection platform 2 and is connected with the standard flowmeter 1 in series;

a frequency modulation fan 4 for generating negative pressure to make the gas pass through the turbine flowmeter 3 and the standard flowmeter 1;

a frequency converter 5 for changing the operating power of the frequency-modulated fan 4;

the straight pipe section 6 is arranged on the front side of an air inlet of the turbine flowmeter 3 and used for rectifying and guiding air flow;

the laser sensor 7 is arranged on the front side of an air inlet of the straight pipe section 6, and a laser head faces the inside of the pipe orifice of the straight pipe section 6 and is used for measuring the number of high-frequency pulses;

the frequency modulation fan 4 is started to generate negative pressure, so that airflow sequentially passes through the straight pipe section 6, the turbine flowmeter 3 and the standard flowmeter 1, the rectifier 31 in the turbine flowmeter 3 can rectify and accelerate the airflow, the laser sensor 7 emits laser rays to irradiate on the blade 321 of the impeller 32 of the turbine flowmeter 3, when the impeller 32 of the turbine flowmeter 3 rotates, the laser sensor 7 collects high-frequency pulse signals and transmits the high-frequency pulse signals to an upper computer, and the upper computer calculates the test error rate of each flow point required by the test through the following formula:

in the formula: e₁Is the relative indication error of the turbine flowmeter 3,%; v₁Is a turbine flowCumulative flow rate value, m, of meter 3³；V_SCumulative flow value, m, converted to the state at the flowmeter, for a standard flowmeter 1³(ii) a N is the high-frequency pulse number collected and measured by the laser sensor 7, imp/s; n is the number of blades 321 of the impeller 32 of the turbine flow meter 3, k is the average meter coefficient (total number of revolutions per cubic meter of gas, impeller or gear ratio) counted by the turbine flow meter 3, (m)³)^-1。

The light emitted by the laser head 71 is parallel to the axis of the straight tube section 6.

The distance between the laser head 71 of the laser sensor 7 and the pipe orifice of the straight pipe section 6 is not less than 5CM, and the length of the straight pipe section 6 is more than 3 times of the nominal diameter of the straight pipe section.

The light of the laser sensor 7 passes through the gate-leaf gap of the rectifier 31 from the inlet of the turbine flowmeter 3 and reaches the blade 321 of the impeller 32, and a high-frequency signal is extracted.

In summary, the present invention has the advantages that the gas is uniformly distributed by the rectifier 31 to push the impeller 32 of the turbine flowmeter 3 to rotate, after the flow velocity is stable, the impeller blades 321 uniformly distributed along the circumference stably rotate under the push of the gas, rapidly cut the light of the laser, therefore, the laser sensor 7 generates a high-frequency pulse signal which is in direct proportion to the flow, the blades 321 of the impeller 32 of the turbine flowmeter 3 are generally designed to be more than 10, the laser sensor 7 can collect more than ten pulses per circle of the impeller 32, even at the minimum flow point, the general frequency can reach about 50-300, the detection signal greatly shortens the effective time required by the verification, on the basis of not changing the signal output structure of the flowmeter and not increasing the cost, the high-efficiency verification of the flowmeter is realized by adopting the new method, and the problem of long detection time of small flow is well solved.