Accuracy assurance measures for metal tube float flowmeters

Thread Content

1. The fluid flows through the flow meter from bottom to top. Metal tube float flow meters are generally installed vertically, with a verticality of less than 2°; when installed horizontally, the horizontal angle should also be less than 2°, so as not to disrupt production during troubleshooting or cleaning. Metal tube float flowmeters installed on process pipelines should be equipped with bypasses. 2. There should be a 250 mm straight pipe section at the outlet, and at the inlet of the metal tube float flow meter, there should be a straight pipe section with a length of at least 5 times the pipe diameter. To ensure the accuracy of instrument measurements. 3. If the medium contains ferromagnetic materials, it is advisable to consider installing a magnetic filter between the valve and the straight pipe section. 4. When used for gas measurement, it is necessary to ensure that the pipeline pressure is at least 5 times the pressure loss of the flow meter, so as to allow the float to operate stably. When thermal insulation measures are necessary, and if the temperature of the medium being measured is above 220°C or if the fluid temperature is too low to prevent crystallization, a jacketed type should be used to enable cooling or heat retention. 5. The pipeline flanges, fasteners, gaskets must meet the same standards as those of the flow meter in order to ensure proper installation and operation of the instrument. 6. This product requires no maintenance once the device is operating properly. Failures often occur shortly after the device starts operating, due to incomplete cleaning of the pipes, which causes the float to get stuck by solid particles; in such cases, the pointer of the indicator stays fixed at a certain position. At this point, the valves on both sides of the flow meter should be closed first, the flow meter removed, the float taken out for cleaning, and then reinstalled. 7. The flanges of the process piping must be coaxial with and parallel to the flange of the flow meter, in order to avoid deformation of the flow meter caused by the piping. Appropriately increase pipe supports to avoid pipe vibration and reduce the axial load on the flow meter. 8. To ensure the performance of the instrument, no ferromagnetic materials are allowed within at least 100 mm around the instrument, as it transmits signals through magnetic coupling. 9. Instruments for measuring gases, which are calibrated at specific pressures, will experience a pressure drop at the float if the outlet is directly connected to the atmosphere, resulting in data distortion ； Under such operating conditions, a control valve should be installed at the outlet of the instrument. 10. Due to the deformation of PTFE under uneven pressure when installing instruments lined with PTFE, the flange nuts should be tightened in a uniform and symmetrical manner.