Orifice Flanges Guide
Orifice flanges are specialized flanges designed for flow measurement in piping systems. They work in conjunction with an orifice plate to create a pressure differential that can be measured and converted to flow rate.
What Are Orifice Flanges
Orifice flanges consist of a matched pair of flanges with an orifice plate sandwiched between them. The orifice plate has a precisely machined hole that creates a restriction in the flow stream.
How They Work
- Flow Restriction: Fluid passes through the orifice plate opening
- Pressure Drop: Velocity increases, creating pressure differential
- Measurement: Pressure taps measure upstream and downstream pressure
- Calculation: Flow rate calculated using Bernoulli equation
Key Components
- Orifice Plate: Precision machined plate with concentric or eccentric bore
- Flange Pair: Matched flanges with pressure tap connections
- Pressure Taps: Located at flange, vena contracta, or pipe taps
- Gaskets: Special gaskets with tabs for plate alignment
- Jack Screws: For easy plate removal and maintenance
Types of Orifice Plates
| Tipo | Application |
|---|---|
| Concentric | Clean liquids, gases, and steam |
| Eccentric | Liquids with solids or gases with liquids |
| Segmental | Slurries and dirty fluids |
| Quadrant Edge | Low Reynolds number flows |
Applicazioni
- Natural gas flow measurement
- Steam flow monitoring
- Water and wastewater treatment
- Chemical process control
- Petroleum refining
- HVAC system balancing
Vantaggi
- Simple, proven technology
- No moving parts
- Wide range of sizes and materials
- Relatively low cost
- Easy to install and maintain
- Interchangeable orifice plates
Limitations
- Permanent pressure loss (energy cost)
- Limited turndown ratio (typically 3:1 to 5:1)
- Requires straight pipe runs upstream and downstream
- Accuracy affected by wear and erosion
- Not suitable for dirty or abrasive fluids
Installation Requirements
- Minimum 10-20 pipe diameters straight run upstream
- Minimum 5-10 pipe diameters straight run downstream
- Proper gasket alignment (no gasket protrusion into flow)
- Correct orifice plate orientation (bevel downstream)
- Pressure tap lines properly purged and filled
Standard e specifiche
- ASME MFC-3M: Measurement of fluid flow in closed conduits
- ISO 5167: Orifice plates, nozzles, and Venturi tubes
- AGA Report No. 3: Natural gas flow measurement
- ASME B16.36: Orifice flanges
Accuracy Considerations
Typical accuracy ranges from 0.5% to 2% of full scale, depending on:
- Orifice plate machining tolerance
- Pressure tap location accuracy
- Differential pressure transmitter accuracy
- Installation conditions
- Fluid properties and flow regime
Orifice flanges remain one of the most widely used flow measurement devices in process industries due to their simplicity, reliability, and cost-effectiveness.
WhatsApp: +86-18658777855
E-mail: 1007788887@qq.com
Ti potrebbe interessare anche
DIN Flanges vs ANSI Flange: ANSI Class 150, PN Rating and Selection Guide
A practical guide comparing DIN flanges and ANSI flange standards, including ANSI Class 150, PN meaning, flange rating ANSI systems, bolt patterns, dimensions and selection tips.
Flange Coupling Guide: Coupling Flange Type, Flanged Coupler and Shaft Applications
A practical guide to flange coupling, coupling flange type selection, flanged coupler structure, flange shaft coupling applications, installation and maintenance.
What Is an Orifice Flange? Orifice in Piping, Orifice Pipe and Flow Measurement Guide
A practical guide explaining what an orifice flange is, how an orifice in piping works, orifice pipe flow measurement, pressure taps, orifice plates and selection tips.