The Hedland Flow Meter for Petroleum Fluids is a rugged, yet low cost variable area flow meter. These in-line flow rate indicators are industrial class and are ideal for petroleum and petroleum-based fluids. They feature quality metal construction in aluminum, brass, or stainless steel, with port sizes ranging from 1/4 to 3 inches .

The aluminum and brass models are rated for operating pressures up to 3500 PSI/241 bar maximum with a 3:1 safety factor. The stainless steel model is pressure rated for 6,000 psi/414 bar maximum (5,000 psi/345 bar maximum for 3/4" to 1-1/2" series) with a 3:1 safety factor. Temperature range options include standard -20 to 240°F and high temperature up to 500°F for intermittent applications .

All Hedland variable area flow meters use a sharp-edged annular orifice, formed between the open-centered piston and a contoured metering cone. The piston is held in a "no flow" position by a calibrated retention spring. Flow creates differential pressure, moving the piston against the spring. The indicator is magnetically-coupled to the moving piston and read against a graduated flow scale. The design offers direct reading, installation in any position, 360° rotatable guard/scale, no flow straighteners required, relative insensitivity to shock/vibration, and good viscosity stability .

Applications include hydraulic fluid power systems and petroleum-based fluids. The meters are calibrated for 0.876 S.G. and provide ±2% full scale accuracy with ±1% repeatability .