Orifice flanges
The most commonly used meter due to its quality/price ratio and versatility. It consists of an orifice plate with a calibrated bore enclosed between two flanges. Holes for measuring the differential pressure value are provided on the flanges, commonly called “pressure taps” in the types specified by the reference standard.
They can be supplied in a wide range of materials and ratings.
Orifice flanges with annular chamber
Where it is not possible to take pressure readings directly on the flanges, the orifice plate can be enclosed between two annular chambers (or ring-type chambers). These rings are then enclosed between common line flanges.
This type of meter is also used in gas measurement where greater stability is required, as the static pressure read will be the average of the values present around the pipe wall.
Meter run
PFor measurements on piping with a diameter smaller than DN50 (2″), the orifice plate is calculated according to a dedicated ASME standard. Generally, for this type of meter, in addition to the orifice plate with its containment flanges, a straight section of piping both upstream and downstream, with flanged or weld-on ends, is also supplied.
Calibrated meter sections
Where high measurement accuracy is required, for example for custody transfer or performance tests, a complete meter is supplied, including straight pipe sections upstream and downstream. These pipe sections are internally machined to guarantee the characteristics required by the reference standard. The complete meter is subsequently sent to an accredited laboratory for calibration aimed at improving its accuracy.
Upon request, these meters can also be supplied complete with accessories such as flow straighteners, thermowells, valves, and supplementary connections.
