Variable Area flow meters measure volumetric flow of liquids and gases. This technology is based on the variable area principle, where flow raises a float in a tube, increasing the area for passage of the fluid through the meter.

Measuring Principle
Variable area meters measure volumetric flow of liquids and gases. An orifice is positioned within the piston assembly and forms an annular opening with the contoured metering cone. The piston assembly carries a cylindrical ceramic magnet that is coupled to an external flow indicator that moves precisely in direct response to the piston movement. A calibrated spring opposes flow in the forward direction, decreasing viscosity sensitivity.