ST – Restriction Orifice Multi Plate Spools

Restriction Orifice Multi Plate Spools are used as a means of controlling line pressure in systems using pressure critical componentry when a single Restriction plate is not adequate. The design is based on a series of Restriction Orifice Plates welded into a custom made pipe spool which creates an overall pressure drop and in turn provides the required downstream pressure.

Each restriction orifice is calculated and designed taking into account the medium characteristics, the pressure loss and the process data into account.

The use of multi-holed plates is often used if the noise at each plate is above the industry accepted 85dB.

For liquid restriction applications the spool is normally the same line size. For gas restriction applications the multi plate spool is sometimes required to expand across pressure drop stages due to the expansion of the gas under the reduced pressures.

Contact us for more information.


  • Spool Facing: Raised Face ‘RF’, Ring Type Joint
  • ‘RTJ’ or BX ring (API 6A) – serrated machined face to ASME B16.5
  • A data plate is affixed to the spool containing TAG, ANSI Class, Size (in DN), Material & Part number
  • Plate bores are advised during the engineering phase
  • Materials: Carbon Steel, Stainless Steel 304 & 316, Duplex, Super Duplex, Monel, Inconel
  • Sizes: 0.5” to 24” (15DN to 600DN) – other sizes available upon request
  • ANSI Class: 150-2500 ANSI & 4,000 to 10,000 PSI

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