ABSTRACT
The moving portion of the oscillating piston meter consists of a slotted cylinder that oscillates about a dividing bridge that separates the inlet port from the outlet port. It has only two moving parts: the two impellers, made out of wear-, abrasion-, and corrosion-resistant thermoplastics. A proximity switch senses the passing magnets implanted in the impeller lobes and transmits the resultant pulses to a counter. A special variety of the rotating lobe flowmeter is the ovalgeared metering elements. The flow provers that allow for inline recalibration without interruption of the process flow are described below. Dividing the volume of the prover by the time it takes to displace its volume gives the calibrated flow rate. In order to minimize the disturbance to the process flow, inline ballistic flow provers have been developed. Therefore, the prover can be permanently installed in an operating pipeline, upstream or downstream of the flowmeter which is being calibrated.
