The oscillating piston flowmeter is the underlying principle of our PD flowmeters. The PD meter consists of a measurement chamber or flow tube in which a piston made of high durable and inert plastic is housed. The chamber is of a known volume and one revolution of the piston from mean position means a sweep of known cyclic volume. Therefore, when there is no flow in the line, the pis... https://www.fluidyne.co.in/Products/liquid-level-transmitters/oscillating-piston-flowmeter