Plastic Rotame is the most widely used variable area flow meter

  •   The working principle of Plastic Rotameter

        Plastic Rotameter is the most widely used variable area flow meter. It consists of a tapered tube; when fluid passes through the tube, it raises the float. A larger volume flow puts more pressure on the float, raising it higher. In the liquid, the speed of the flowing liquid is combined with the buoyancy to make the float rise; for gas, the buoyancy is negligible, and the height of the float is mainly set by the speed of the gas and the subsequent pressure.

      Generally, the pipe is installed vertically; when there is no flow, the float stays at the bottom, but once the fluid flows upward from the bottom of the pipe, the float will start to rise. Ideally, the height that the float moves through is proportional to the fluid velocity and the annular area between the float and the pipe wall. As the float rises, the size of the annular opening increases, thereby reducing the pressure difference across the float.

      The system reaches equilibrium and the float reaches a fixed position. When the upward force exerted by the fluid flow balances with the weight of the float-the float is suspended by the fluid flow. You can then read the flow rate of a specific fluid density and viscosity. Of course, the size and composition of the rotameter will depend on the application; if everything is properly calibrated and sized, the flow can be read directly from the scale according to the position of the float. Some rotameters will allow you to manually adjust the flow using a valve. Early designs had free floats that could rotate with changes in gas and fluid pressure; because of their rotation, these devices were called rotameters.

      Plastic Rotameter usually provides calibration data and direct reading scales for common fluids (air and water). To determine the size of a rotameter used with other fluids needs to be converted to one of these standard formats; for liquids, water equivalent in gpm; for gases, equivalent air in standard cubic feet per minute (scfm) flow. Calibration tables for these standard flow values, combined with slide rules, nomograms, or computer software used to determine the size of the rotameter, are usually provided by the manufacturer.

      Panel Flow Meter is also our product, welcome to consult and purchase.