Ultrasonic flowmeter classification
●Insert ultrasonic flowmeter: can be installed and maintained without stopping production. Ceramic sensors are used for non-stop production installation using dedicated drilling equipment. Generally for mono measurement, in order to improve measurement accuracy, three channels can be selected.
● Pipe-type ultrasonic flowmeter: It is necessary to cut the pipeline installation, but the subsequent maintenance can be stopped. Mono or 3-channel sensors are available.
● External clip-on ultrasonic flowmeter: capable of performing fixed and mobile measurements. It is installed with a special coupling agent (silicone rubber cured at room temperature or high-temperature long-chain polymer grease) and does not damage the pipeline during installation.
● Portable ultrasonic flowmeter: portable, built-in rechargeable lithium battery, suitable for mobile measurement, with magnetic sensor.
1, non-contact measurement method, small size, easy to carry
2, suitable for on-site measurement of various sizes of pipe sound guiding media
3, built-in nickel-metal hydride rechargeable battery working time of more than 20 hours
4, user interface is flexible, easy to use
5, intelligent on-site printing function to ensure the integrity of the flow data
6, equipped with an integrated aluminum alloy protective box, can be used in harsh outdoor environments
● Hand-held ultrasonic flowmeter: small size, light weight, built-in rechargeable lithium battery, hand-held, with magnetic sensor.
● Explosion-proof ultrasonic flowmeter: used for explosive liquid flow measurement, it is explosion-proof and intrinsically safe. That is, the converter is explosion-proof and the sensor is intrinsically safe.
Test equipment: one 500MΩ insulation resistance tester, one multimeter.
(1) When the pipeline is filled with medium, measure the resistance between terminals A, B and C with a multimeter. The resistance between A-C and B-C should be equal. If the difference is more than 1 time, there may be leakage of the electrode, condensation on the outer wall of the measuring tube or the junction box.
(2) In the case of lining drying, measure the insulation resistance between A-C and B-C with MΩ meter (should be greater than 200MΩ). Then use a multimeter to measure the resistance of the two electrodes in terminals A and B and the measuring tube (should be in short-circuit communication). If the insulation resistance is small, indicating that the electrode is leaking, the entire flowmeter should be returned to the factory for repair. If the insulation is reduced but there is still more than 50 MΩ and the inspection result of step (1) is normal, the outer wall of the measuring tube may be damp, and the inside of the outer casing may be dried by a hot air blower.
(3) Use a multimeter to measure the resistance between X and Y. If it exceeds 200 Ω, the excitation coil and its lead wire may be open or poorly connected. Remove the terminal block check.
(4) Check the insulation resistance between X, Y and C, which should be above 200 MΩ. If it is lowered, dry the inside of the casing with hot air. In actual operation, the decrease in coil insulation will result in increased measurement error and unstable instrument output signal.
(5) If it is determined that the sensor is faulty, please contact the manufacturer of the electromagnetic flowmeter. The general site cannot be solved and needs to be repaired by the manufacturer.
Installation of plug-in electromagnetic flowmeter
The plug-in electromagnetic flowmeter sensor installation upstream straight pipe section is not less than 5D (D means pipe diameter), the downstream straight pipe section is not less than 2D:
1. Vertical installation. When the sensor is inserted into the pipeline, it should be less than 5° from the vertical diameter of the pipeline section. It is suitable for measuring the cleaning medium with small vibration of the pipeline.
2, inclined installation, the axis of the sensor and the axis of the pipe to be tested is 45 °, suitable for large pipe diameter and measuring the flow of liquid containing other impurities in the medium, the installation method is small, not suitable for entanglement.
There are two ways to insert the insertion point of the electromagnetic flowmeter sensor: one is inserted into the central axis of the pipe to be tested (ie 1/2 times the diameter of the pipe); the other is inserted into the inner wall of the pipe at 1/4 of the pipe.
1. Clean the welding slag and burrs of the base of the pipe to be tested.
2. Turn off the upstream flow control valve or use low pressure water supply.
3. Install the DN50 ball valve on the mounting base. Pay attention to the long cavity of the ball valve. Check whether the ball valve can be fully open and fully closed. Install the screw seat, compression nut and rubber sealing ring onto the ball valve and loosen the positioning nut. Insert the sensor into the rod through the ball valve and insert it into the pipe to be tested. At the same time, it should be noted that the direction of the sensor direction indicator rod should be consistent with the flow direction of the fluid. Ordering Information Please specify the name of the tested medium, working pressure, medium temperature, flow rate (flow rate) range, pipe diameter and the pipe network to be tested.