CONICAL ENTRANCE ORIFICE PLATE
Conical orifice plate, in standards referred to as “orifice plate with conical entrance”, has a similar design of reversed centric orifice plate, whose entrance into measuring aperture is conically chamfered.
Most often conical entrance orifice plate is placed into piping in a flanged joint. Except for CSN standard, sealing surfaces of the orifice plates can be manufactured in compliance with EN, DIN, GOST, in compliance with American ASME and ANSI standards or, on specification and requirement of customer.
ISO 5167-2 and ISO/TR15377 standards define possibility to use conical entrance orifice plate for diameters up to 500 mm. Conical entrance orifice plate is manufactured in nominal diameters ranging from DN 15 up to DN 500 and it can have chamber or individual tapping similarly as centric orifice plate. Usual construction width of the orifice plate with chamber tapping is 60 mm; usual construction width of the orifice plate with individual tapping is 40 mm. For pipelines of 40 mm diameter and higher, conical entrance orifice plate is manufactured as an individual disc determined for placement between flanges with a flange tapping.
The orifice plate can be also manufactured in so-called weld-in design. It contains straight lengths of piping downstream the plate. Placement into pipe by welding has the advantages such as material savings on flanges and subsequently minimized leakage in the flanged joint. Weld-in design of orifice plates is especially convenient for high-pressure parts of piping systems and distribution or, in piping systems requiring seismic resistance.
Upon agreement with the customers, outlets of differential pressure are always customized to various options of primary element attachment to the measuring circuit.
For the production of flanges for orifice plates with chamber tapping there is mostly used carbon steel or stainless steel and the disc is made of stainless steel. For the production of orifice plate with individual tapping, there is mostly used refractory alloyed steel or stainless steel. Upon agreement, conical entrance orifice plate with both chamber and individual tapping can be made of special materials based on nickel titanium alloy or, tantalum, orifice plates are produced of plastic materials, too.
Conical entrance orifice plate is manufactured as a working meter.
Conical entrance orifice plate is used for the measurement of viscous fluid flow (e.g. oils) as well as in operating modes with low Reynolds numbers. Its advantage lies in the construction simplicity similar to centric orifice plates. Both types of orifice plates can be incorporated in vertical or horizontal piping.