neral approach presented herein. All of these meters measure the amount of flow passing through them by Generally, pressure drop increases relative to the meter speed and the volumetric efficiency increases with increasing absolute viscosity, but not in a directly pro- portional or linear way. The maximum volumetric effi- ciency usually occurs in the middle of the range of . 14-6.2 Calibration Requirements The recommended practice is to calibrate these meters in the same fluid at the same temperature as is expected in their intended performance asme pdf test environment or ser- vice. Unlike the turbine meters, these machines are rela- tively insensitive to piping installations and otherwise poor flow conditions; in fact, they are more of a flow disturbance than practically anything else upstream or down in plant piping. If the calibration laboratory does not have the identical fluid, the next best procedure is to calibrate the meter in a similar fluid over the same cutting the fluid into chunks of known volume and range of [Eq. (14-6.2)] expected UL pdf in service. This recom- counting the volumes.
They are also called volumeters. 148 mendation implies duplicating the absolute viscosity of FLOW MEASUREMENT Outlet Housing Sliding vane Cam roller Block Cam Rotor A Inlet Main shaft Measuring chamber ASME PTC 19.5-2004 (a) Metering Chamber of a Sliding Vane Meter Measuring chambers (b) Measuring Chamber and Disk Rotating vanes Timing gears (c) Schematic Representation of the Operating Features of a Rotating Vane Meter GENERAL NOTE: Here the gears have 2 "teeth" or lobes. (d) Cross Section Through a Gear-Type Meter Fig. 14-6 Positive Displacement Volumeters 149 ASME PTC 19.5-2004 the two fluids. It has been reported [1] that temperature effects, apart from influence on viscosity, were negligible rela