Orifice Plates

Product Summary

· Built to the recommendations of ASA, ISA, ASME and ISO

· Concentric, Eccentric, Quadrant edge, Bore with Counter bore and Segmental

· Plates are made in 304 and 316 SST, Monel, Hastelloy C and B, Alloy 20 and Teflon

The orifice meter consists of a flat orifice plate with a circular hole drilled in it. There is a pressure tap upstream from the orifice plate and another just downstream. There are in general three methods of placing the taps. The coefficient of the meter depends upon the position of taps.

· Vena contracta location - Tap location 1 pipe diameter (actual inside) upstream and 0.3 to 0.8 pipe diameter downstream from face of orifice

· Flange location - Tap location 1 inch upstream and 1 inch downstream from face of orifice

· Pipe location - Tap location 2.5 times nominal pipe diameter upstream and 8 times nominal pipe diameter downstream from face of orifice

The discharge coefficient - c_d - varies considerably with changes in area ratio and the Reynolds number. A discharge coefficient - c_d - of 0.60 may be taken as standard, but the value varies noticeably at low values of the Reynolds number.

The pressure recovery is limited for an orifice plate and the permanent pressure loss depends primarily on the area ratio. For an area ratio of 0.5, the head loss is about 70 - 75% of the orifice differential.

· The orifice meter is recommended for clean and dirty liquids and some slurry services.

· The rangeability is 4 to 1

· The pressure loss is medium

· Typical accuracy is 2-4% of full scale

· The required upstream diameter is 10 to 30

· The viscosity effect is high.

· The relative cost is low.

Orifice Plates

Product Detail– Orifice Plates

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