Hastelloy C276 Nickel Alloy Flanges Concentric Orifice Plate Eccentric Orifice Plate

Hastelloy C276 Nickel Alloy Flanges Concentric orifice plate Eccentric orifice plate

1. The orifice plate is one of the simplest devices that can be easily introduced to the flow system. Itfrequently used than any other flow meter. It acts as a primary device for measuring flow rate. Thisdevice works on the same principle as that of venturi meter. Orifice meter causes a significant amountof pressure drops compared to venturi. So orifice plates often used as restriction plates.

2. Types of orifice plates

. The typical designs of orifice plates are

. Concentric orifice plate. Eccentric orifice plate.Segmental orifice plate

. Quadrant edge orifice plate

Concentric orifice plate

A concentric sharp edged orifice plate is the simplest and least expensive of the head meters. It isusually made of stainless steel. Other materials like nickel, Monel, etc. used when it is needed a goodcorrosive resistant property. The accuracy of these type orifice is very high.

Eccentric orifice plate

It is similar to the concentric orifice plate except for the offset hole which is bored tangential to acircle. Location of the bore prevents accumulation of solid materials or foreign particles and makes ituseful for measuring fluids containing suspended solid particles. The eccentric orifice is less accurateand has a high number of uncertainty when to compare to the concentric orifice plate. It is used whenliquid consists of a large amount of gas dissolved in it.Segmental orifice plate

This is used for the same type of services as an eccentric orifice plate. It has a hole which is a segmentof a circle. It is used with fluid containing more solid particles in it. They are more expensive than theeccentric orifice.

Quadrant edge orifice plate

This type is used for flaws of dense fluid such as crudes, slurries, and viscous flows. Its edges are rounded to form a quarter circle. They are useful in the pipe have a low diameter (less than 2 inches).The drain hole is provided or located the bottom when gases are measured, to allow condensate topass in order to prevent its building up at the Orifice plate. Similarly, a vent hole is located at the topwhen liquids are measured so that gases can pass and thus avoid gas pocket.

3. Advantages and disadvantages of orifice plate

Advantages

1. Simple in construction, the standards for construction and calibration are readily available.2. They are cheap; their price does not increase dramatically with size.3. Easy to install and remove.

4. They are efficient and reliable for many years.

5. Available in many materials.

6. Easy to measure flow rate, because it produces the considerable pressure drop across the orifice.

7. They can be used in a wide range of sizes.

8. Their characteristics are well known and predictable.

Disadvantages

1. Relatively high permanent pressure drop.

2. Their characteristic may change due to erosion and corrosion.

3. It may cause clogs in slurries. Not good with fluid having high viscosity.4. The fluid must be in single phase and homogeneous.5. Square root characteristics.

Coefficient of discharge of the orifice is about 0.6 - 0.75, and it causes loss of head about 60 - 70%

4. ASTM B564 Hastelloy® C276 Forgings Chemical Composition

5. ASME SB564 Hastelloy Alloy C-276 Forgings Mechanical Properties

6. Equivalent Grades for C276 Hastelloy Industrial Pipe Flanges

7. Application:

• Used for measurement of flow for fluids containing solids and slurries.
• It is also used for vapors and gases where condensation is present