What is a square edge orifice plate?

The square edge on the hole in an orifice plate helps to minimize contact with the fast-moving fluid stream going through the hole. Square-edged orifice plates may be installed in either direction, since the orifice plate looks exactly the same from either direction of fluid approach.

Why orifice plate is beveled?

Orifice plates are beveled on the downstream side to help minimize the plate’s contact with the flowing gas stream passing through the meter. The amount of beveling required on plates of the same thickness decreases as the meter tube inside diameter (ID) increases.

What are the different types of orifice plate?

There are 4 types of Orifice Plates that we will discuss:

• Concentric Orifice Plate (Hole is in the center)
• Eccentric Orifice Plate (Hole is off center)
• Segmental Orifice Plate.
• Others – such as Conical and Quadrant, and Edged Entrance types.

What happens if orifice plate is backwards?

Reverse installation of an orifice plate in a natural-gas orifice meter can cause a reading for calculated flow that is 15–17% less than actual. Backwards installation of the orifice plate, that is with the beveled edge upstream, will invalidate the governing calculations described in AGA`s Report No.

How do you identify an orifice in a pipeline?

An orifice tab is welded on the orifice plate which extends outer of the line giving an indication of the orifice plate.

How do you size an orifice plate?

Beta Ratio As discussed in flow instrumentation principles the beta ratio (β = d/D) is the ratio of the orifice plate bore diameter (d) and the pipe internal diameter (D). During sizing, keep your beta ratio in the range 0.3 to 0.7. This is the range of beta ratio that gives the best performance from the orifice plate.

Which way do orifice plates go?

Ideally, this edge will be knife-sharp. Looking at the side-view of this orifice plate, the intended direction of flow is left-to-right, with the sharp edge facing the incoming fluid stream and the bevel providing a non-contact outlet for the fluid.

Which is the main disadvantage of orifice meter?

Disadvantages of orifice meter: It requires the flow of axial velocity vectors. It causes a pressure drop in the fluid. Its accuracy is affected by the density, pressure and viscosity of the fluid. The range of measurement of viscosity limits of fluids.

How do you calculate orifice flow rate?

Equations for orifice plate flow rate calculation

1. Maximum flow: Max flow = K x √ΔPmax.
2. Constant: K = max flow/√ΔPmax.
3. Differential pressure: ΔP = (flow/K)²
4. Output (4-20 mA): Output mA = [(%ΔP) x 16 mA] + 4 mA.

How do you install an orifice plate?

General Installation requirements:

1. The orifice meter must be installed between two mating flanges in the pipe.
2. For liquid metering, the pipe should run full at the measuring section.
3. The diameter of the tube must be circular over the measured length.

How do you make an orifice plate?

Design Considerations of Orifice Plate

1. Square Root Relationship.
2. Density.
3. Beta (β) Ratio. β ratio < 0.2 Means: β ratio > 0.7 Means:
4. Reynolds Number.
5. Selection of Differential Pressure Transmitter Range.
6. Location of Pressure Taps. Flange Taps: Venacontractra & Radius Taps: Corner Taps:
7. Installation.