Orifice Meter With Corner Taps
6.3 Limitations. Prefabricated orifice meter assemblies cannot measure over
an infinite range. The turndown of an orifice meter is 3:1 and, therefore,
predetermined orifice sizing is required to obtain accurate measurement data.
6.4 Installation. Prefabricated meter assemblies are permanently installed
meters fitted in a specially designed length of pipe with permanently located
pressure taps. The complete assembly is installed in the pipe where flow is
to be measured. The prefabricated assembly is sized for a particular flow
range and is calibrated accordingly.
7. MAINTENANCE. The following procedures are the minimum required for the
most common types of units. When developing q aintenance schedules, refer to
the manufacturer's instructions. Annually disassemble meter and inspect and
perform maintenance as follows:
(a) Check orifice for wear, i.e., roundness, size, and squareness of edge.
(b) Plate should be examined for warping with a straightedge.
(c) Plate should be examined for watermarks indicating condensate damming.
(d) Check pressure taps for burrs and/or debris.