WELDED-IN CENTRIC ORIFICE PLATE
Centric orifice plate is a thin plate with a circular orifice and its centre is placed in the axis of piping. This design contains straight lengths of piping downstream the orifice plate. Welded-in centric orifice plate has the advantages, such as material savings on the flanges and consequently minimized leakage in the flange joint.
Differential pressure tapping can be chamber, individual or flanged. Due to technology of the production of the welded-in orifice plates, chamber tapping is usually used for inside parameters ranging from DN 50 up to DN 80. Outlets of differential pressures are upon agreement with customers always customized to various options of primary element attachment to the measuring circuit.
Centric orifice plate is manufactured in the nominal sizes ranging from DN 15 up to DN 1,000, for nominal pressures up to PN 320. For the production of welded-in orifice plates there are most often used combinations of used carbon and stainless steels for the measurement of fluid flow, and refractory steel for the measurement of steam flow e.g. alloyed steels 14MoV6-3/15 128, 10CrMo9-10/11CrMo910, 13CrMo4-5, 16Mo3 and X10CrMoVNb9-1.
Centric orifice plate is manufactured either as a working meter or, as a specified meter with metrological verification complying with the technical particulars and conditions of pattern approval.
The greatest advantage of centric orifice plate is its construction simplicity and its unambiguous definition by ISO 5167-2 standard, thanks to which, it is predetermined for the widest use in all flow measurement areas. Upon agreement, welded-in centric orifice plate can be manufactured also in the range of DN and PN different than stated above.
Great operational reliability and applicability of welded-in orifice plate in measurement of fluid, gas and steam flow, is its great advantage. The welded-in design of orifice plate is especially suitable for use on high-pressure side of piping systems and distribution (high-pressure steam, feed water) or, in piping systems requiring seismic resistance.
ISO 5167-2 standard defines possibility to use centric orifice plate for diameters of piping ranging from 50 mm up to 1,000 mm. In relation to ISO/TR 15377 centric orifice plate in welded-in design can be used for piping diameters 25 – 50 mm, provide it with drainage or vent aperture.
Centric orifice plate in welded-in design can be incorporated both in the vertical and horizontal piping.