Thread Content
Vortex flow meters should be installed in locations with as little vibration and impact as possible. At vibration frequencies of 5–20 Hz, the vibration acceleration should not exceed 1g; otherwise, vibration damping measures should be taken. For example, fixed support frames are installed on the pipeline where the vibration source is located at the flow meter installation site. ④ Hazardous areas: Flowmeters designed for use in hazardous areas must comply with the iaIICT1-6 explosion protection standard. Installers must unconditionally comply with the \"Regulations on Electrical Safety in Explosive Hazardous Areas of the People’s Republic of China\" and carry out their work in strict accordance with the installation requirements for explosion-proof electrical equipment. Sufficient space should be available around the installation location of the vortex flow meter; meters installed at high heights should preferably have a working platform to facilitate installation and maintenance. Furthermore, for the convenience of maintenance inspections, there should be AC 220V power sockets available nearby for measuring instruments. It is preferable to install the flow meter indoors; if installation outdoors is necessary, measures should be taken to protect it from sunlight and moisture. The flow meter should be placed away from high-power motors, frequency converters, high-power transformers, and radio transceivers, as this can prevent the instrument from functioning properly. The vortex flow meter features an on-site LCD display that shows real-time temperature, pressure, instantaneous flow rate, and cumulative flow volume. It also has temperature and pressure compensation functions. When measuring gases or steam, compensation is carried out by referring to tables based on the actual measured temperature and pressure, thereby ensuring that changes in temperature and pressure do not affect the accuracy of the flow meter due to changes in gas density. Static testing of vortex flowmeters: Measure the static current by connecting a standard resistor in series at 24V, using a digital voltmeter for measurement, or with an on-site indicator. Under conditions with no traffic signal, the static current is 4 mA, and the on-site indicator is at the 0% position. If there is a deviation, the potentiometer W1 can be adjusted. However, before making any adjustments, it is necessary to use an oscilloscope or frequency meter to check that there is no frequency signal (square wave). It is only meaningful to adjust the zero setting when the frequency-to-current converter has no input. When the coefficient board is not connected, W1 can be adjusted directly to achieve zeroing. Dynamic testing of vortex flowmeters: Dynamic testing refers to testing when the transmitter receives a signal input. Enter the upper limit flow signal; the TP will output a frequency of 41,000 Hz. At this point, the frequency-to-current conversion circuit should provide a full-scale output, and the transmitter’s output current should be 20 mA DC. If there is any deviation, the range potentiometer W2 can be adjusted to ensure that the output remains at 20 mA DC. Generally, to change the range during use, it is only necessary to calculate the KB value; by setting this value on the encoder switch, the flow range of the transmitter can be altered without the need to adjust the W2 potentiometer. Analog detection method for vortex flowmeters: When conducting circuit tests in the laboratory, the analog detection method can be used. Replace the probe signal with a frequency generator signal; the shield terminal of the frequency generator’s output should not be connected to any terminal, but rather to the common ground terminal. The signal output terminal can be connected to either terminal of the amplifier board’s input terminals. The frequency of the signal output by the frequency generator is adjusted to lie within the range specified in the transmitter’s certificate of conformity; the signal amplitude increases slightly at higher frequencies, and it is generally kept within the range of 1–2 VPP, sufficient to trigger a response from the amplification circuit.