"At a higher flow rate more area (between the float and the tube) is needed to accommodate the flow, so the float rises. The float hooks into spiral grooves on the glass (to stabilize the float) causing the float to rotate as it moves up or down. One edge of the float is compared with graduations on the glass to measure the flow rate of the fluid." . "Qualified" . "ROTAMETER FLOW METER" . "ROTAMETER FLOW METER" . "RDS882719" . "A variable area flow meter which consists of a tapered tube of glass with a float inside that is pushed up by flow and pulled down by gravity." . "u20683" . "2006.06.08" . .