Weighing of load being lifted by hydraulic cylinder

摘要

The load (28) is supported by a plate (26) on the end of the vertical piston rod (24) of the double-acting cylinder (20) which has pressure gauges (32, 33) on its feed and drain tubes (30, 31). For the weighing operation, the piston (22) is immobilised and the rate of damping of the consequent oscillation is observed. The changes of pressure on both sides of the piston are sampled during one or more cycles and averaged. The wt. is deduced from the difference between the averages with allowance for the piston areas on which the pressures are exerted.