Multi-hole orifice plate is similar to centric orifice plate however, in its disc there are more orifice holes. Use of multi-hole orifice plate is limited by β = d/D, the orifice plate is made for β = 0.4 up to 0.65. This orifice plate is mostly placed in a flanged joint. Except for CSN, sealing surfaces of the orifice plates can be manufactured also in compliance with EN, DIN, GOST standards, American ASME and ANSI standards or, on request and specification of the customer.

Multi-hole orifice plate can be manufactured in so-called weld-in design, too. Weld-in design of the multi-hole orifice plate contains straight lengths of piping downstream the disc. Weld placement into the pipe has the advantages such as material savings on the flanges and subsequently minimized leakage in the flanged joint.

Multi-hole orifice plates are manufactured according to type of differential pressure tapping:

• Orifice plates with corner tapping, i.e. orifice plates with chamber or individual tapping
• Orifice plates with pressure tapping D “downstream” and D/2 “upstream” the disc
• Orifice plates with flanged tapping

Chamber orifice plates, i.e. orifice plates with chamber corner tapping, are manufactured in nominal diameters ranging from DN 15 up to DN 1,000 for nominal pressures up to PN 40, max. up to PN 100. Use of chamber orifice plates for higher pressures is not recommended due to its design. Orifice plate with chamber tapping consists of these main parts: a two-piece flange with annular chamber and a disc. The disc is clamped between two pieces of flanges and attached by a sealing. The pressure tapping outlets are led out of the flanges. The disc is replaceable. Usual construction width of the orifice plate with chamber tapping is 60 mm.

For the production of flanges in orifice plate with chamber tapping there is mostly used carbon or stainless steel. The disc is made of stainless steel. On agreement the multi-hole orifice plate can with chamber tapping can be made of special materials based on nickel and titanium alloys or, tantalum. Orifice plates are made of plastic materials, too.

Multi-hole 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.

Except for advantages of centric orifice plates (such as simplicity, replaceability and reliability), multi-hole orifice plates also have the advantage of smaller installation length enabling wider possibilities of their use. Passage of the measured fluid through several tapered cross-sections reduces demand on minimal straight lengths of piping downstream and upstream the orifice plate necessary for proper functioning of this type of meter. Multi-hole orifice plate design enables use of straight lengths of piping “downstream” the orifice plate min. 4D long. Design of orifice plate with chamber tapping can be manufactured in DN and PN ranges different than stated above. Multi-hole orifice plate can be incorporated both in vertical and horizontal piping.