First, the selection of gas flowmeter
Gas measurement is a difficult point in gas flow measurement, because in addition to gas components such as CO, CO2, CH4, H4, and air in the gas medium, there are also solid impurities such as moisture and naphthalene, tar, dust, and corrosive substances. It has a great impact on the primary detection element. Generally, there are both furnace gas and coke oven gas; both for production and domestic use, coupled with the need for thick transmission pipelines and low gas pressure, etc., have increased the difficulty of selecting the flowmeter.
用于煤气计量的优点 Advantages of gas ultrasonic flowmeter for gas measurement
From the working principle of the gas ultrasonic flowmeter, it can be known that the gas flow rate is only related to the parameters of the measurement pipeline and has nothing to do with the nature of the gas, that is, it is not affected by the gas composition, density, temperature, etc., so it is unique in gas composition with complex composition and configuration. The advantages. Because the lower limit of the flow rate required by the gas ultrasonic flowmeter is relatively low, it is more suitable for large-diameter, low-flow gas measurement. In addition, the gas ultrasonic flowmeter has the following unique metrological advantages:
1. The probe is only inserted into the pipe wall of the gas pipeline, so there is no resistance, no pressure loss, no moving parts, no wear and no hidden dangers during the measurement process. This is unmatched by other flowmeters. It is especially valuable today.
2. It can be installed and disassembled continuously, and it is extremely convenient for on-line maintenance and maintenance. It is very important for continuous production and gas metering which is difficult to stop. It also avoids the waste of personnel and property to clean the pipeline after gas stop.
3. It is suitable for various working environments, and can work stably for a long time under the environment of dirt, corrosion, stickiness, high temperature, cold, vibration, etc .; it is very suitable to use in the corrosive and dirty medium such as gas and the environment with explosion danger. .
4. The measurement accuracy is high, and it can reach a high accuracy of 1% under complete compensation.
Application of gas ultrasonic flowmeter in gas measurement
In the process of measuring the gas flow rate of gas ultrasonic flowmeters, we also found that the gas ultrasonic flowmeters have different effects in different gas media. The effect of gas metering for furnace gas is better than that of coke oven gas.
The gas ultrasonic flowmeter has the best measurement effect for generating furnace gas. It can be used continuously for more than two years if the probe is cleaned once every three months.
检修维护的经验： Extensive experience in the maintenance of gas ultrasonic flowmeters :
(1) When the gas ultrasonic flowmeter is used for the first time, it is necessary to ensure that the parameter settings are accurate and the waveform is adjusted to the best state.
(2) The probe must be cleaned regularly, especially when used for coke oven gas measurement.
(3) The flowmeter must be reliably grounded to prevent surrounding electromagnetic interference from ultrasonic signals.
(4) The upstream and downstream gas pipes of the flowmeter probe should be drained frequently to ensure the cleanness of the measurement location.
(5) In order to ensure the accuracy of measurement, be sure to add on-line compensation devices for gas temperature and pressure.
(6) The secondary meter should be installed indoors to prevent gas corrosion in the environment and affect its service life.
后，进行安装时，会遇到很多问题，我公司技术人员将一些常见的问题归纳如下，并予以解答： After purchasing the ultrasonic flowmeter , users will encounter many problems during the installation. Our technicians summarize some common problems as follows and answer them:
1. When installing an ultrasonic flowmeter, why should it be reliably grounded?
(1) Eliminate hidden dangers and increase safety factor.
(2) Eliminate the electrostatic interference of the meter itself.
(3) Eliminate the interference of external space on the instrument.
2. How to solve when there is frequency conversion on site?
(1) Separate the power supply of the ultrasonic flowmeter from the variable frequency power supply to avoid power supply interference.
(2) Make the ultrasonic flowmeter a different room from the inverter to avoid space interference.
(3) The ground wire of the ultrasonic flowmeter must be well connected, and the cable shield must be connected.
(4) If an output port is selected, a shielded wire should be used for reliable grounding.
3. How to detect when the ultrasonic flowmeter is connected to the power without display?
(1) Check for AC voltage input on the power supply board of the flowmeter.
(2) Check the main board of the flowmeter to see if the power board has a DC voltage output.
(3) Open the panel to see if the socket is tightly inserted.
4. How to choose the installation point?
(1) Select straight pipe sections filled with liquid.
(2) The measurement point should be 10D upstream and 5D downstream without any valve interference.
(3) Ensure that the temperature of the measurement point is within the working range.
(4) Select pipe sections that are uniform and dense and easy for ultrasonic transmission.
(5) Avoid installing ultrasonic flowmeters in pumps, high-power radio stations, and locations with magnetic and vibration interference