Orifice Plates Manufacturer

Q1. What is an orifice plate?

An orifice plate is a thin, precision-bored metal plate clamped between a pair of orifice flanges to measure flow by differential pressure. As fluid passes through the calibrated bore it accelerates and its pressure drops; the pressure difference across the plate, sensed through the flange tappings, is proportional to the flow rate. It is the most common primary element in flow measurement.

Q2. What are the types of orifice plate?

Concentric (round centred bore — the standard for clean fluids), eccentric (bore offset to the wall, for fluids with entrained gas or solids), segmental (part-circle opening, for slurries), and quadrant/conical-edge (for viscous, low-Reynolds-number flow). The type is chosen for the fluid and any second phase.

Q3. How does an orifice plate work?

It restricts the flow, so the fluid speeds up through the bore and its static pressure drops downstream. A differential-pressure transmitter reads the pressure difference between the upstream and downstream flange tappings, and the flow rate is calculated as proportional to the square root of that differential pressure, following ISO 5167.

Q4. Which way does an orifice plate face?

The sharp (square) edge of the bore must face upstream, into the flow, with the bevel (if any) downstream. The stamped tab should be readable, the vent hole positioned at the top (to pass gas in a liquid line) and the drain hole at the bottom (to pass condensate in a gas line). Installing the plate backwards causes large measurement errors.

Q5. What are the vent and drain holes for?

A small vent hole at the top of the bore lets trapped gas pass in a liquid line, and a drain hole at the bottom lets condensate pass in a gas line, preventing a second phase from building up against the plate and disturbing the measurement. The hole is sized and positioned per the service.

Q6. What standard governs orifice plates?

ISO 5167 is the principal standard for orifice-plate flow measurement (bore, edge sharpness, tappings, and calculation), often used with AGA 3 for gas. The plate is dimensioned to fit ASME B16.5 orifice flanges. We manufacture plates to ISO 5167 / ASME with the bore calculated for your flow data.

Q7. What materials are orifice plates made from?

SS 304/316/316L and 321, Monel, Inconel, Hastelloy, and carbon steel (A105). The grade is chosen for the fluid, pressure, and temperature — for example SS 321 for high-temperature steam and Monel/Inconel/Hastelloy for corrosive flows.

Q8. Do orifice plates come with orifice flanges?

They work as a set: the orifice flanges hold the plate and carry the pressure tappings, and the orifice plate is the bored primary element. We supply plates and flanges separately or as a complete metering assembly with bolting, gaskets, and the calculated bore, certified with EN 10204 3.1 MTC.