The metal tube float flowmeter is a variable area flow measuring instrument commonly used in industrial automation process control. It has the characteristics of small size, large detection range and convenient use. It can be used to measure the flow of liquid, gas and steam, and is especially suitable for medium flow measurement with low flow velocity and small flow. In the course of use, we often encounter phenomena such as indication failure. How to solve these uncomplicated faults, the following is a brief analysis for everyone:Specific phenomenon 1: The actual flow is inconsistent with the indicated valueCauses of failure: due to corrosion, changes in float flow, volume, and maximum diameter; changes in the inner diameter of the tapered pipe. Solution: Change to corrosion-resistant materials. If the size of the float is the same as before the replacement, it can be converted or re-calibrated according to the new weight and density; if the size is also different, it must be re-calibrated. When the maximum diameter of the cylinder surface of the float is worn and the surface is rough, which affects the measured value, replace the rotor with a new one. Floats made of or lined with engineering plastics may swell and change in maximum diameter and volume. Use a float of a suitable material.Specific phenomenon 2: The actual flow is inconsistent with the indicated valueThe cause of the failure: foreign matter layers such as scale and dirt attached to the float and tapered tube. Solution: cleaning to prevent damage to the inner surface of the conical tube and the maximum diameter cylindrical surface of the float, and maintain the original surface roughness.Specific phenomenon 3: The actual flow is inconsistent with the indicated valueThe cause of the failure: changes in temperature and pressure of gas, steam, and compressive fluids. Solution: Convert and amend according to the new conditions.Specific phenomenon 4: The actual flow is inconsistent with the indicated valueCauses of failure: fluid pulsation, rapid changes in gas pressure, and fluctuations in the indicated value. Solution: install a buffer tank or switch to an instrument with a damping mechanism.Specific phenomenon 5: The actual flow is inconsistent with the indicated valueThe cause of the failure: There are bubbles in the liquid and droplets in the gas. Solution: Eliminate bubbles or droplets.Specific phenomenon 6: The actual flow is inconsistent with the indicated valueThe cause of the failure: when used in liquids, gas is trapped in the dead corner of the instrument, which affects the buoyancy of the float. Solution: It has a significant impact on small flow meters and when operating at low flow rates, and remove the gas.Specific phenomenon 7: The flow rate of the metal tube float flowmeter changes and the float or pointer moves sluggishlyThe cause of the failure: there is foreign matter such as particles between the float and the guide shaft, or the guide shaft is stuck due to bending. Solution: disassemble and clean, remove foreign matter or fixed layer, straighten the guide shaft, the bending of the guide shaft is mostly caused by the rapid opening and closing of the solenoid valve, the rapid rise of the float, and the change of operation mode.Specific phenomenon 8: The flow changes and the float or pointer moves sluggishlyThe cause of the failure: the iron powder or particles attached to the magnet with the magnetic coupling float assembly indicates that the connecting rod or the pointer is stuck. Solution: disassemble and clear, and use bypass pipe to fully clean the pipeline in the early stage of operation. Install a motion link that connects the filter manually with the magnet on the front of the instrument, and adjust it if there is a stuck part. Check whether there is any foreign matter obstructing the movement between the rotating shaft and the bearing, remove or replace the parts.Specific phenomenon 9: The flow rate changes and the float or pointer moves sluggishlyCause of failure: Engineering plastic floats and tapered pipes are swollen or stuck due to thermal expansion. Solution: Replace parts with corrosion-resistant materials. For higher temperature media, try not to use plastics, and use corrosion-resistant metal parts.Specific phenomenon 10: The flow changes and the float or pointer moves sluggishly
The cause of the failure: the magnetically coupled magnet has decreased. Solution: Remove the meter, move the float up and down by hand, confirm that the pointer of the indicating part is moving smoothly; if it does not follow or follows unstable, replace with new parts or magnetize. In order to prevent the weakening of magnetism, it is forbidden for the two coupling parts to strike each other.
Post time: 21-09-21