Variable-area flow meter FMIPL- BPRM-100

positive displacementdifferential pressureorifice

The Bypass flow meter consists of a mainline Orifice plate, a set of Orifice Flanges Or a carrier ring, a flow meter, range Orifice, Bypass piping with Isolation Valves. (i) Mainline Orifice Plate:- The purpose of the mainline orifice plate is to create the pressure differential. As the flow rate varies across this mainline orifice, the pressure differential across this plate also varies and it is this variation, which makes the meter function. (ii) Orifice Flanges / Carrier Ring:- Orifice flanges / carrier rings serve two functions. First, they hold the mainline orifice plate in the proper position within the pipeline. Secondly they channel a portion of the flow out of the high-pressure side of the orifice and return it again to the low-pressure side. This function may be accomplished with other than flange taps. The Bypass piping may be connected directly to the pipeline in the form of pipe taps, radius taps OR vena contracta taps. (iii) Variable Area Flow Meter:- As discussed above, a flow meter (Glass Tube Rotameter OR Metal Tube Rotameter) is placed in the Bypass piping to measure the bypass flow. (iv) Range Orifice:- The range orifice is a small orifice placed in the bypass piping either before OR after the flow meter. This orifice is sized so that the total pressure drop through the bypass-piping equals the pressure differential across the mainline orifice. (v) Bypass Piping:- The bypass piping connects the upstream side of the mainline taps to the inlet side of the flow meter and the downstream side of the mainline taps to the outlet of the flow meter.