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 piston is stationary. When liquid begins flowing, the piston displaces liquid from inlet to outlet with a constant cyclic volume per position.
This revolution is read by an electronic transducer which converts mechanical motion to electric signal. Consequently the k factor or calibration factor is also unique for different sizes of meters. The k factor is essentially a correlation between cyclic volume and electric signal.