How to install and use a glass rotameter

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A rotameter is an indicating instrument that directly measures the flow rate of fluid in a pipe by means of a conical glass tube marked with a flow scale and the height position of a float inside the tube. It is used to measure the flow rate of unclouded liquids, gases, and other unidirectional media; it is more convenient and intuitive than other instruments. Therefore, it is widely used in various industrial sectors and research institutions. Before using and installing a glass rotameter, it is necessary to check its technical parameters such as the measurement range, accuracy class, rated operating pressure, temperature, and other factors to ensure that they meet the requirements for use. Before installation, the lining material in the flow meter that serves as protection during transportation should also be removed. Also check whether the cone tube is damaged and whether the float can move up and down freely; installation can proceed only after confirming that everything is normal. The newly installed piping should be flushed thoroughly before installing the glass rotameter. The minimum division value of the rotameter should be positioned at the lower end; it must be installed vertically on a vibration-free pipeline, with the angle between the rotameter’s center line and the vertical line not exceeding 5 degrees. Due to their heavy weight, large-diameter flowmeters may require measures such as reinforced supports when necessary to prevent pipe bending. During installation, it is also necessary to prevent the rotameter from being subjected to excessive forces such as tension, compression, and torsion. To avoid excessive external force that could damage the cone tube. Depending on the various operating conditions, a filter should be installed upstream of the rotameter when necessary, to prevent impurities from contaminating and clogging it. If the fluid is unstable and exhibits pulsating flow, a buffer can be installed to ensure accurate measurement by the rotameter, thereby eliminating the pulsations. When using a rotameter, first slowly open the control valve on the pipeline upstream of the meter, and then adjust the flow rate using the control valve, in order to prevent sudden opening from causing the float to rise rapidly and damage the cone-shaped tube. To ensure the measurement accuracy of the rotameter during use, it is recommended that the flow rate of the fluid being measured be at least 60% of the upper limit of the rotameter’s calibrated flow rate.