阅读说明：本技术 一种超声波燃气表超声波飞行时间校准方法 (Ultrasonic wave flight time calibration method for ultrasonic gas meter ) 是由 邹航 黄华兵 李季 于 2019-10-17 设计创作，主要内容包括：本发明提供一种超声波燃气表超声波飞行时间校准方法。本发明首先计算超声波计量通道内无气体流动时的超声波飞行时间和超声波计量通道内有气体流动时的超声波飞行时间,然后设置飞行时间的基准值,通过声速采样对超声波计量通道内进行检测,根据不同情况修正飞行时间的基准值,完成飞行时间校准。本发明方法,通过根据不同的情况修正飞行时间的基准值,以此来排除干扰,提高采样到的飞行时间的可信度,从而得到较准确的流量数据。(The invention provides an ultrasonic flight time calibration method for an ultrasonic gas meter. The method comprises the steps of firstly calculating the ultrasonic flight time when no gas flows in the ultrasonic metering channel and the ultrasonic flight time when gas flows in the ultrasonic metering channel, then setting a reference value of the flight time, detecting the ultrasonic metering channel through sound speed sampling, correcting the reference value of the flight time according to different conditions, and finishing the flight time calibration. The method of the invention eliminates the interference by correcting the reference value of the flight time according to different conditions, improves the reliability of the sampled flight time and obtains more accurate flow data.)

1. An ultrasonic wave flight time calibration method for an ultrasonic gas meter is characterized by comprising the following specific steps:

step (1), calculating the ultrasonic flight time when no gas flows in the ultrasonic metering channel:

taking the transducer A as a transmitting device, taking the transducer B as a receiving device, wherein the flight time of ultrasonic waves from the transmitting device to the receiving device is Ta, the flight time of the ultrasonic waves from the receiving device to the transmitting device is Tb, the length of an ultrasonic wave metering channel is X, and the propagation speed of the ultrasonic waves in the gas in the ultrasonic wave metering channel is v₁；

Ta＝Tb＝X/v₁

Step (2), calculating the ultrasonic flight time when gas flows in the ultrasonic metering channel:

the actual flight time of the ultrasonic waves from the transmitting device to the receiving device is TA, the actual flight time from the receiving device to the transmitting device is TB, and the flow rate of the gas is v₂t, then:

TA＝Ta+X/v₂t

TB＝Tb-X/v₂t

and (3) setting a reference value of the flight time, detecting the inside of the ultrasonic wave metering channel through sound speed sampling, correcting the reference value of the flight time according to different conditions, and finishing the flight time calibration:

sampling 10 times when the power is firstly switched on, calculating the average value of 10 times of flight time, taking the obtained average value as the reference value of the flight time when the sound velocity is firstly sampled, wherein DTa is the reference value of the flight time of the ultrasonic wave from a transmitting device to a receiving device, and DTb is the reference value of the flight time of the ultrasonic wave from the receiving device to the transmitting device, and then sampling the sound velocity once every 2 seconds;

1. when the situation that Ta and Tb change in the same direction is detected, the environment of the ultrasonic metering channel changes, and then the reference values DTa and DTb are updated simultaneously;

2. when the reverse change of Ta and Tb is detected, judging whether | | | DTa-Ta | - | DTb-Tb | | | is greater than a threshold value tau or not; when the | | DTa-Ta-DTb-Tb | | | | is less than tau, the normal flow of the ultrasonic metering channel is represented; when | | | DTa-Ta | - | DTb-Tb | | > is more than or equal to tau, eliminating interference factors in a resampling mode, sampling for 3 times again to determine that the variation of Ta and Tb really exists, if the flight time is not changed after resampling is carried out again, considering the last sampling as interference, not carrying out flow calculation, if the situation that | | | | DTa-Ta | -DTb-Tb | | > is more than or equal to tau still exists, recording the current Ta and Tb, taking the average value of | DTa-Ta | and | DTb-Tb | for the flow, and updating the reference value DTa or DTb with larger variation; the interference factors comprise unstable flow field, changed sensor characteristics, impurities in a flow channel and displacement of the sensor caused by vibration of a meter;

3. when only Ta or Tb is detected to change, eliminating interference factors in a resampling mode, conducting sampling for 3 times again, determining that the variation of Ta or Tb really exists, if the flight time is not changed after sampling is conducted again, considering the previous sampling as interference, not conducting flow calculation, and if only Ta or Tb is detected to change, considering that sensor characteristics change, and updating the changed reference value DTa or DTb.

Technical Field

The invention belongs to the technical field of intelligent control of instruments, and particularly relates to an ultrasonic flight time calibration method for an ultrasonic gas meter.

Background

The ultrasonic metering channel is provided with a transmitting sensor and a receiving sensor, the gas flow is determined by calculating the difference value of the flight time in the use process, but the sound velocity is changed due to environmental factors such as temperature and the like in the actual use process, so that the calculation of the flight time is influenced. This patent provides a method to determine environmental changes and correct for variations in flight time through software.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an ultrasonic flight time calibration method for an ultrasonic gas meter.

An ultrasonic wave flight time calibration method for an ultrasonic gas meter comprises the following specific steps:

step (1), calculating the ultrasonic flight time when no gas flows in the ultrasonic metering channel:

taking the transducer A as a transmitting device, taking the transducer B as a receiving device, wherein the flight time of ultrasonic waves from the transmitting device to the receiving device is Ta, the flight time of the ultrasonic waves from the receiving device to the transmitting device is Tb, the length of an ultrasonic wave metering channel is X, and the propagation speed of the ultrasonic waves in the gas in the ultrasonic wave metering channel is v₁；

Ta＝Tb＝X/v₁

Step (2), calculating the ultrasonic flight time when gas flows in the ultrasonic metering channel:

the actual flight time of the ultrasonic waves from the transmitting device to the receiving device is TA, the actual flight time from the receiving device to the transmitting device is TB, and the flow rate of the gas is v₂t, then:

TA＝Ta+X/v₂t

TB＝Tb-X/v₂t

and (3) setting a reference value of the flight time, detecting the inside of the ultrasonic wave metering channel through sound speed sampling, correcting the reference value of the flight time according to different conditions, and finishing the flight time calibration:

sampling 10 times when the power is firstly switched on, calculating the average value of 10 times of flight time, taking the obtained average value as the reference value of the flight time when the sound velocity is firstly sampled, wherein DTa is the reference value of the flight time of the ultrasonic wave from a transmitting device to a receiving device, and DTb is the reference value of the flight time of the ultrasonic wave from the receiving device to the transmitting device, and then sampling the sound velocity once every 2 seconds;

1. when the situation that Ta and Tb change in the same direction is detected, the environment of the ultrasonic metering channel changes, and then the reference values DTa and DTb are updated simultaneously;

2. when the reverse change of Ta and Tb is detected, judging whether | | | DTa-Ta | - | DTb-Tb | | | is greater than a threshold value tau or not; when the | | DTa-Ta-DTb-Tb | | | | is less than tau, the normal flow of the ultrasonic metering channel is represented; when | | | DTa-Ta | - | DTb-Tb | | > is more than or equal to tau, eliminating interference factors through a resampling mode, sampling for 3 times again, determining that the variation of Ta and Tb really exists, if the flight time is not changed after resampling is carried out again, considering the last sampling as interference, not carrying out flow calculation, if the situation that | | | | DTa-Ta | -DTb-Tb | | > is more than or equal to tau still exists, recording the current Ta and Tb, taking the average value of | DTa-Ta | and | DTb-Tb | for the flow, and updating the reference value DTa or DTb with larger variation. The interference factors include unstable flow field, changed sensor characteristics, impurities in the flow channel and vibration of the gauge, which causes displacement of the sensor.

3. When only Ta or Tb is detected to change, eliminating interference factors in a resampling mode, and sampling for 3 times again to determine that the variation of Ta or Tb really exists, if the flight time is not changed after sampling again, considering the last sampling as interference, not performing flow calculation, and if only Ta or Tb is detected to change, considering that the sensor characteristic changes, and updating the changed reference value DTa or DTb;

the invention has the following beneficial effects:

the method of the invention eliminates the interference by correcting the reference value of the flight time according to different conditions, improves the reliability of the sampled flight time and obtains more accurate flow data.

Drawings

FIG. 1 is a schematic diagram of the structure of an ultrasonic metering channel in the method of the present invention.

Detailed Description

The invention is further illustrated with reference to the following figures and examples, without however being limited to the scope of the invention as described below.

An ultrasonic wave flight time calibration method for an ultrasonic gas meter comprises the following specific steps:

step (1), calculating the ultrasonic flight time when no gas flows in the ultrasonic metering channel:

as shown in FIG. 1, the transducer A is used as a transmitting deviceThe energy device B is used as a receiving device, the flight time of the ultrasonic wave from the transmitting device to the receiving device is Ta, the flight time of the ultrasonic wave from the receiving device to the transmitting device is Tb, the length of the ultrasonic wave measuring channel is X, and the propagation velocity of the ultrasonic wave in the gas in the ultrasonic wave measuring channel is v₁；

Ta＝Tb＝X/v₁

Step (2), calculating the ultrasonic flight time when gas flows in the ultrasonic metering channel:

the actual flight time of the ultrasonic waves from the transmitting device to the receiving device is TA, the actual flight time from the receiving device to the transmitting device is TB, and the flow rate of the gas is v₂t, then:

TA＝Ta+X/v₂t

TB＝Tb-X/v₂t

and (3) setting a reference value of the flight time, detecting the inside of the ultrasonic wave metering channel through sound speed sampling, correcting the reference value of the flight time according to different conditions, and finishing the flight time calibration:

sampling 10 times when the power is firstly switched on, calculating the average value of 10 times of flight time, taking the obtained average value as the reference value of the flight time when the sound velocity is firstly sampled, wherein DTa is the reference value of the flight time of the ultrasonic wave from a transmitting device to a receiving device, and DTb is the reference value of the flight time of the ultrasonic wave from the receiving device to the transmitting device, and then sampling the sound velocity once every 2 seconds;

1. when the situation that Ta and Tb change in the same direction is detected, the environment of the ultrasonic metering channel changes, and then the reference values DTa and DTb are updated simultaneously;

2. when the reverse change of Ta and Tb is detected, judging whether | | | DTa-Ta | - | DTb-Tb | | | is greater than a threshold value tau or not; when the | | DTa-Ta-DTb-Tb | | | | is less than tau, the normal flow of the ultrasonic metering channel is represented; when | | | DTa-Ta | - | DTb-Tb | | > is more than or equal to tau, eliminating interference factors through a resampling mode, sampling for 3 times again, determining that the variation of Ta and Tb really exists, if the flight time is not changed after resampling is carried out again, considering the last sampling as interference, not carrying out flow calculation, if the situation that | | | | DTa-Ta | -DTb-Tb | | > is more than or equal to tau still exists, recording the current Ta and Tb, taking the average value of | DTa-Ta | and | DTb-Tb | for the flow, and updating the reference value DTa or DTb with larger variation. The interference factors include unstable flow field, changed sensor characteristics, impurities in the flow channel and vibration of the gauge, which causes displacement of the sensor.

3. When only Ta or Tb is detected to change, eliminating interference factors in a resampling mode, conducting sampling for 3 times again, determining that the variation of Ta or Tb really exists, if the flight time is not changed after sampling is conducted again, considering the previous sampling as interference, not conducting flow calculation, and if only Ta or Tb is detected to change, considering that sensor characteristics change, and updating the changed reference value DTa or DTb.