Orifice Flange

At Arc Alloys Ltd we can supply you with all your orifice flange needs. An orifice flange is very similar to other flanges with the exception that they have holes in the sides of the flange that are horizontal to the bolt holes. The holes are there to accommodate instrumentation items such as flow speedometers and pressure gauges.

Dimensional standards:

  • ANSI B16.5
  • 47 Series A and B16.47 Series B
  • API 6A
  • API 17D
  • BS EN 1092-1
  • BS 4504
  • BS 10
  • Din
  • JIS
  • Norsok L-005
  • Bespoke to customer drawings / design.

Standard grades:

  • ASTM / ASME A182 / SA182 F51 / F60 / 31803/ 1.4462
  • ASTM / ASME  A182 / SA182 F53/F55 / 32750 / 32760
  • ASTM  / ASME A182 / SA182  F44 / 31254
  • ASTM / ASME / B564 / SB564 UNS NO6625 / Alloy 625 / Inconel® 625
  • ASTM / ASME / B564 / SB564 UNS NO8800 / Alloy 800 / Incoloy® 800
  • ASTM / ASME / B564 / SB564 UNS NO8810 / Alloy 800H / Incoloy® 800H
  • ASTM / ASME / B564 / SB564 UNS NO8811 / Alloy 800HT / Incoloy® 800HT
  • ASTM / ASME / B564 / SB564 UNS NO6600 / Alloy 600 / Inconel® 600
  • ASTM / ASME / B564 / SB564 UNS NO6601 / Alloy 601 / Inconel® 601
  • ASTM / ASME / B564 / SB564 UNS NO8020 / Alloy 20 / Carpenter® 20
  • ASTM / ASME / B564 / SB564 UNS NO2200 / Alloy 200
  • ASTM / ASME / B564 / SB564 UNS NO2201 / Alloy 201
  • ASTM / ASME / B564 / SB564 UNS NO6625 / Alloy 400 / Monel® 400
  • ASTM / ASME / B564 / SB564 UNS NO7718 / Alloy 718
  • ASTM / ASME / B564 / SB564 UNS NO8825 / Alloy 825 / Incoloy® 825
  • ASTM / ASME / B564 / SB564 UNS NO10276 / Alloy C276 / Hastelloy®C276
  • ASTM / ASME / B564 / SB564 UNS NO6022 / Alloy 22 / Hastelloy® 22
  • ASTM / ASME / B564 / SB564 UNS NO10675 / Alloy B3 / Hastelloy® B3
  • ASTM / ASME / A182 / SA182 UNS NO8028 / Alloy 28 / Sanicro®28
  • ASTM / ASME / B564 / SB564 UNS NO5500 / Alloy K500 / Monel® K500
  • ASTM / ASME / A182 / SA182 F304 / F304L / F304H
  • ASTM / ASME / A182 / SA182 F316 / F316L / F316H
  • ASTM / ASME / A182 / SA182 F321 / F321H

Standard facings:

  • Raised face
  • Ring-type joint
  • Flat face
  • Male/female
  • Tongue/groove

Orifice flanges are used in correlation with orifice meters and are used for measuring the flow of liquids and gases and extensively used in the oil and gas industries.

How are orifice flanges used?

When two orifice flanges are used together it is described in the industry as an orifice flange union. Each individual orifice flange comes with two pipe taps which are used for measuring the pressure drop of the flow through the orifice plate. Orifice plates don’t actually come with flanges and they are sized depending on the process requirements. It is necessary to use two jack screws to spread the flanges apart so that the orifice plate can be changed.

An Orifice plate is a thin plate with a hole in the middle and it is placed in a pipe in which liquid flows. When the fluid reaches the orifice plate, the fluid goes through the small hole and the velocity and the pressure of the liquid changes. The liquid expands and the velocity and pressure changes again. If you measure the difference in liquid pressure between the normal pipe section and where it flows through the plate, the volumetric and mass flow rates can be calculated.

Orifice flanges tend to be installed in a straight run of pipe so that turbulence can be avoided at the plate.

When you are installing the orifice plate flange the pressure taps need to be at the same height to each other. When making the calculation for the orifice plate, the static head of the tubes should be the same on both sides of the orifice plate. It is advised that pressure taps should not be installed facing down because the taps could potentially become plugged with debris in the line.

The main benefits of orifice flanges include:

  • Measures the fluid flow rate in the pipe.
  • Gives highly accurate flow rate readings and is extremely reliable.
  • Gives you a cost effective ways of measuring flow rate compared to other methods.
  • There is no need to drill and make bores on pipes for inserting instrumentation probes.

Orifice Flanges generally come with either Raised Faces or RTJ (Ring Type Joint) facings and area available in different sizes and materials depending on your requirements.
To find out more about our comprehensive range of orifice flanges then please get in touch with the team at Arc Alloys Ltd and we will be happy to help