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EMCO Orifice Plate Series ISB/1 EP for RF Flanges


The EMCO Orifice Plate is used as a primary element in flow measurement of liquid, gas and steam applications based on the differential pressure principle. According to this working principle, the orifice plate creates a flow restriction in the pipeline to allow measurement of the resulting pressure drop and flow rate. Our orifice plates have been tested and tried for over 50 years and measure up to the highest industry and compliance standards. 

The Orifice Plate Series ISB/1 EP is especially designed for installations with limited space due to the flow conditioning effect created by the 5 hole design. The design therefore combines a traditional single bore orifice plate with a flow conditioner which can reduce the flow meter from 20 times inner pipe diameter to 5 times inner pipe diameter upstream in a straight pipe run.




Design and calculation standards
2” - 24" according to ANSI B 16.36
Pressure rating
300 - 600 lbs RF
Plate thickness
3 - 16 mm depending on plate size
β (d/D)
0,5 - 0,6
AISI 316, 22Cr Duplex 25Cr Duplex, Monel, 6Mo Hastelloy, titanium and others on request
Mounting style
Between raised face flanges according To ANSI B16.36 or DIN 19214, other standards on request
Orifice plate shapes
Square edge
With name plate in AISI 316 with the following inscription : TAG no., serial no., pressure rating, inner pipe diameter., beta equivalent, material.

Technical Data

+/- 1 %
Pressure loss
Depending on β, for β equal to 0,6 : ca. 60 % of the differential pressure measured
Limits for Reynolds No
Re > 5000
Allowable differential pressure
2,5 bar



Before installation, the orifice plate must be kept clean and protected against corrosion and physical damage. It is also important that you pay careful attention to to the sharp edge of the plate. Once ensured that it is clean, install the orifice plate carefully such that the orifice bore aligns with the centre of the pipeline. Tap location varies depending on whether it is used for liquid, gas or steam. It is not supplied with any safety devices and must not be used for higher pressure, than stated on the name plate. The pipe system must therefore be equipped with a safety device. However, this type of primary element requires no special maintenance.

Download the installation guide above for more detailed information. 

Who to contact?

Christoffer Thrane
Sales & Marketing Manager


Learn about the important difference between orifice plates and restriction plates