Meriam 951 Orifice Plate User Manual

Model 951, Orifice plates concentric-segmental-eccentric, Orifice plates design criteria & tolerances

Meriam Process Technologies

www.meriam.com ph: 800.817.7849 fax: 216.281.0228

Model 951

Orifice Plates

Concentric-Segmental-Eccentric

The most common primary flow element is the concentric orifice plate,

often called the “sharp-edged” orifice plate. Its main advantages are: low

cost, accuracy, ease of installation, variety of construction material and

quick delivery. Much test data has been compiled about orifice plates

and, with the necessary information, an exacting design can be made

providing for excellent metering accuracy.

Engineered for each application, Meriam orifice plates are precision bored

to exact dimensions with a sharp upstream edge to ensure accuracy.

Orifice information is stamped on the unique handle. This handle is

designed to facilitate storage of the plate without damage to the orifice

bore.

Standard Meriam orifice plates are 304 Stainless Steel. Monel, brass, P.V.C.,

316 Stainless Steel and other materials are available. Meriam orifice plate

dimensions meet ISA specifications. Meriam can provide blank orifice

plates for your own boring, too.

Orifice Plates Design Criteria & Tolerances

Standards and specifications for orifice plates are listed by the ISA, AGA and

ASME.

All of these do not agree in all ways. Please indicate which specifications you

require so we will provide your orifice plates the way you want them.

Edges – Square and sharp, will not reflect a beam of light when viewed with-

out magnification.
Finish – 15-32 micro-inch roughness
Flatness – Flatness within 0.010 inches, per inch of dam height.
Bore – Orifice bore tolerance in strict accordance with AGA. Gas Measure-

ment Committee Report No. 3, ASME Fluid Meters Committee Report, and

with other societies’ recommendations.
Meriam has furnished many orifice plates for nuclear and fossil fired power

plants, chemical plants, refineries, steel mills and to original equipment

manufacturers for incorporation in their equipment and systems.

Meriam can also provide readout instruments and accessories for complete

flow metering installation.

Line Pipe Size

½”-1½”

2” - 3”

3½”-6”

8”-12” 14”-36”

Orifice Edge

Thickness “e”

”

¼”

Orifice Edge Thickness