Deadweight Testers & Gauges
The most accurate instrument available for the measurement of pressure above a few psig is the Hydraulic Deadweight Gauge. This type of gauge operates on the principle of balancing a known mass against the force exerted by an unknown pressure on a piston of known area. When an exact balance is achieved, the unknown pressure "P" is equal to the mass "M" of the weights divided by the area "A" of the piston, according to the formula "P" = "M" / "A". In us, weights are removed or added from the piston's table, as with a double-pan balance until the piston "floats" without net vertical movement.
