FLOWTECH Variable Area Flow Meters TINY ROTAMETERS are intended for general in line metering applications (i.e. for Gas & Liquid) for low flow measurement and for purging applications. These are available in Acrylic Body Tube and Glass Tube design. These are working on the principle of Variable Area. The float moves freely up and down tapered Acrylic Body Tube OR Glass Tube with fluid flow from bottom to top. The float takes up a position where buoyancy forces and the float weight are balanced in proportion to flow rate. The Vertical position of the float as indicated by scale is the measure of the instantaneous flow rate