In the measurement process of ultrasonic flowmeter, because there are many influencing factors involved in the operation process, its performance is seriously affected. Therefore, we should pay close attention to relevant contents and focus on the restriction and control of relevant influencing factors, so as to make the measurement quality and effect more accurate and give play to its due effectiveness.
Main factor affecting the performance of ultrasonic flowmeter metering system
Through the corresponding research and practical demonstration, it can be fully seen that during the operation of the ultrasonic flowmeter metering system, the factors that affect its performance and quality involve many aspects, such as noise, dirt, and a series of other related aspects. Such factors will seriously affect the accuracy and accuracy of metering, and cause serious obstacles to its normal production and operation.
Noise influencing factors
In the ultrasonic flowmeter metering system, there are many pipeline systems involved, such as valves, rectifiers, and other types of choke pipe fittings. These pipeline systems will produce noise of a certain intensity during operation. Due to the complex operating environment of the system, which is often accompanied by noise from other equipment components, it is difficult to accurately judge the on-site noise. Based on the occurrence of such problems, will have a great impact on measurement efficiency and quality. From the perspective of the noise source, it mainly includes the airflow passing through the pipeline at high speed, the probe, and rectifier, the flow regulating valve, etc.
Through the analysis of the operation principle of the flowmeter, it can be seen that when the rated and operating frequency of the ultrasonic flowmeter are kept within the same range, the quality of ultrasonic pulse detection and transmission accuracy will be seriously affected, resulting in the volume flow measurement can not be carried out normally, and even large errors. As the ultrasonic flowmeter will be particularly sensitive to the noise generated during the operation of the pressure-reducing element, some low-noise valves will have a more serious impact on the ultrasonic flowmeter, limiting its normal performance. In the practice of noise reduction, the noise is generally controlled within the acceptable range of the human ear through the application of relevant technologies. However, the range of the acoustic spectrum displayed on the ultrasonic flowmeter is different, and there are large differences, so the measurement effect is deeply affected.
Dirt accumulation factors
During the operation of the ultrasonic flow metering system, because there is a lot of water, iron sulfide powder, or other dirty natural gas on the site, these substances will flow through the ultrasonic flowmeter. In this case, the dirt will gradually accumulate in the pipe of the flowmeter body or attach to the ultrasonic probe. In this case, the measurement accuracy and accuracy of the ultrasonic will be seriously affected. Specifically, its impact is mainly reflected in the following aspects. First, the effective inner diameter of the flowmeter will be seriously reduced, causing the serious blockage, and then the specific reading of the flowmeter will be further increased.
Secondly, the accumulation of dirt on the surface of the ultrasonic probe for a long time will significantly shorten the transmission time and make the flowmeter reading higher. At the same time, if the inside of the flowmeter is seriously corroded, the inner diameter of the flowmeter will be greatly increased after cleaning. Finally, the surface roughness of the inner wall of the meter body and the upstream straight pipe section has a relatively obvious change, which will also lead to a relatively obvious change in the velocity distribution, thus greatly affecting the accuracy and stability of the flowmeter.
The accuracy of temperature and pressure measurement is also a very important factor
The components involved in the ultrasonic flowmeter metering system mainly include a flowmeter, pressure transmitter, temperature transmitter (or temperature platinum resistance), flow computer, online component analyzer, etc. By inputting components, pressure, temperature, flow computer, etc., the operating flow of the flowmeter can be converted into volume under standard reference conditions for trade measurement handover. In the ultrasonic flowmeter metering system, For the thermometers and pressure measuring instruments used on-site, can only be used after they are confirmed to be qualified through corresponding experiments and inspections.
At the same time, we should focus on doing a good job of trial operation to ensure the accuracy of measurement. However, it should be noted that in the specific operation process, it is likely that the temperature or pressure indication of the flow computer is not accurate enough and other related problems may occur. Through the corresponding experimental detection and judgment, it can be seen that because the pressure or temperature measurement is not accurate enough, there will be a large error in the volume under the condition of inaccurate standard reference.
Control measures for factors affecting the performance of ultrasonic flowmeter metering system
Effectively avoid or reduce the negative impact of noise fundamentally
First of all, in order to effectively avoid or reduce the impact of noise on the quality accuracy, in the process of designing the metering pipeline system, it is necessary to scientifically and reasonably evaluate the quality and performance of the relevant components and chokes of the whole system, and strictly detect the noise generated by them. For more special pipeline systems, they should be customized in the design process, and carry out comprehensive communication and exchange with the manufacturer, Then do a good job of targeted treatment, so as to control noise from the source. Secondly, in the process of installing the ultrasonic flowmeter and regulating valve, it is necessary to focus on the series installation. In this process, it is necessary to conduct a scientific and reasonable assessment of the noise level that may appear in the regulating valve, and then focus on consulting the manufacturer to deal with it.
Generally, if a regulating valve is installed downstream of the ultrasonic flowmeter, it may cause a lot of noise, and it is not economical and reasonable. Therefore, it is necessary to install a regulating valve upstream as far as possible. Finally, for some flow control valves, it is very likely that they will collide with the control valve during their operation and generate relatively loud noise, which exceeds the normal frequency range. This situation will seriously affect the accuracy of the metering system, making the entire instrument unable to operate safely and stably. Because such noise can pass both upstream and downstream in the process of propagation.
More effective treatment and reduction of dirt accumulation on the inner wall
First of all, the quality of natural gas should be strictly and carefully tested to further effectively define the more feasible cleaning cycle of straight pipe section and flowmeter. After cleaning the inside of the meter, if it is found that there is serious corrosion, it is necessary to further focus on re-calibration to ensure more accurate measurement results. Secondly, it is necessary to further effectively develop monitoring software suitable for the measurement site to ensure its degree of specialization. In the actual application link, such software can be used to conduct strict and detailed detection on the specific operation of the ultrasonic flowmeter, and then use relevant detection parameters to further effectively judge and evaluate the operation of the measurement system, or possible risk factors, Then make targeted treatment according to the specific situation.
Finally, if the quality of natural gas is poor, in this case, multiple ultrasonic flowmeters can be used for parallel detection to effectively realize the operation of the parallel pipeline system. This method can further effectively reduce or avoid measurement errors.
Focus on the measurement of temperature and pressure to ensure their accuracy
First of all, it is necessary to select the corresponding measuring range to effectively avoid the negative impact of the possible influencing factors during the operation of the instrument, and avoid the working range of the instrument being below 10% of the measuring range. Secondly, prior to the application of the metering system, it is necessary to focus on the detection and verification of pressure and temperature measurements on the site. Finally, the transmitter should be protected scientifically and reasonably in the outdoor process. Corresponding sunshades can be set to effectively avoid the impact of environmental temperature changes on the upper limit of its design working temperature, make its temperature close, and effectively avoid the occurrence of measurement errors.