Paddle-Type Orifice Plates
Product Resources
Paddle-Type Orifice Plates
Our paddle-type orifice plates are precision-machined primary flow elements engineered for dependable differential-pressure measurement and flow control. Designed to be used with orifice flanges, our plates are built by skilled craftsmen using state-of-the-art machining practices to deliver repeatable performance and long service life. Every plate we produce is manufactured to meet or exceed the stringent requirements of API 14.3, ISO 5167, and ISA RP3.2 for geometry, flatness, edge preparation, and dimensional tolerance. We deliver consistent quality you can specify, install, and trust.
Standards & Compliance
We align our manufacturing and inspection processes with the industry’s most widely recognized standards. By building to API 14.3, ISO 5167, and ISA RP3.2, we help ensure the orifice geometry, bore concentricity, and sharp-edge integrity required for accurate, standards-based flow calculations. Our standard surface finish is 30 RMS to support a clean, sharp orifice edge and predictable boundary-layer behavior. If your application requires an alternate finish, we will machine to your specified value and verify it during final inspection.
Materials, Thicknesses & Sizes
We stock plates from 1/8″ to 1/2″ thick in 304 and 316 stainless steel to cover a wide range of service conditions and common flange ratings. Standard line sizes range from 1/2″ to 36″, with additional sizes and materials available on request. When conditions call for alternate alloys—such as duplex or super duplex stainless, nickel alloys, or coated carbon steels—we work with you to match material selection to process fluid, temperature, corrosion allowance, and pressure class.
Plate Styles & Edge Configurations
We offer the plate styles most commonly specified by measurement professionals:
- Concentric: The industry workhorse for clean liquids, gases, and steam where solids are minimal.
- Eccentric: Bore offset toward the bottom (or top) to allow entrained gas or solids to pass, mitigating buildup and improving signal stability.
- Segmental: A segment-shaped opening for higher solids loading or fibrous slurries where a self-scouring jet is beneficial.
- Quadrant-Edge: A radiused inlet for low Reynolds number service to improve discharge coefficient stability at low flow.
Within each style, our edge preparation and bevel orientation follow ISO 5167/ASME/API guidance. We maintain a sharp upstream edge for concentric plates and orient bevels correctly relative to flow direction (especially important for eccentric and segmental designs). If you need a specific bevel angle, inlet radius (quadrant), or tolerance on bore roundness and thickness, we will document and deliver to your print.
Sizing, Beta Ratio & Bore Selection
Correct bore sizing is essential for accuracy, rangeability, and permanent pressure loss. We routinely manufacture bores to support beta ratios (β = d/D) from approximately 0.2 to 0.75, depending on line size and application constraints. Our team can reference your operating envelope—fluid properties, pressure/temperature, expected Reynolds number, desired differential, and allowable head loss—to recommend a bore that balances accuracy with turndown. On request, we can incorporate your meter run details (upstream/downstream straight lengths, taps, and fittings) into the selection to help you meet installation requirements from ISO 5167 and API 14.3.
Surface Finish & Machining Quality
Our standard 30 RMS surface finish provides the right balance of edge sharpness and plate flatness for most services. We machine the plate faces, bore, and bevel with close control of burrs and recast layers, then inspect the orifice edge under magnification to ensure a crisp entrance. Flatness across the sealing surface and paddle is held tight to prevent flange gasket leakage and to maintain parallelism between the plate and flange faces.
Identification & Documentation
Each plate can be clearly marked on the paddle tab with the critical information you specify—line size, ANSI rating, thickness, bore diameter, material grade/heat, flow direction, and serial number for traceability. If you need additional identifiers (beta ratio, calculation basis, tag numbers), we’ll add them per your request. We can also provide dimensional inspection summaries and other supporting documentation upon request.
Installation & Orientation
Our paddle-type plates are designed for straightforward insertion between matched orifice flanges. We machine the paddle for an easy, positive grip during installation, and we can include flow-direction arrows and “UP” orientation marks where applicable. For eccentric and segmental bores, proper orientation relative to solids or gas pockets is critical; we can supply orientation drawings or stamped indicators to simplify field work. When used with the correct gasket materials and tap configuration (corner, flange, or pipe taps), our plates deliver stable, repeatable differential signals.
Quality Assurance
Quality begins with material verification and ends with final inspection before shipment. We verify alloy grade and thickness, confirm bore diameter and concentricity, and check surface finish and edge condition. Our processes ensure that every plate leaving our facility is consistent with your purchase order and the referenced standards. If your project requires additional testing (hardness checks, PMI, or special NDE on request), we will coordinate those services and retain records for your files.
Typical Applications
Our paddle-type orifice plates serve in a broad range of industries and media:
- Oil & Gas: Natural gas custody transfer measurement (with appropriate meter runs), fuel gas, produced water, flare and vent monitoring.
- Refining & Petrochemical: Liquid hydrocarbons, steam balancing, utility systems, process gases.
- Power Generation: Boiler feedwater, condensate, auxiliary steam, air service.
- Water & Wastewater: Raw water intake, treated effluent, chemical dosing, aeration air.
- Pulp & Paper / Mining / Food: Services where segmental or eccentric plates help maintain signal quality in the presence of solids.
Ordering Information
To ensure a perfect fit, please include the following in your order:
- Size (nominal pipe size)
- ANSI Rating (to match your orifice flange class)
- Thickness (1/8″ to 1/2″ standard; others on request)
- Bore Diameter (or desired beta ratio/target flow)
- Material (304 or 316 stainless standard; others on request)
Helpful additions include plate style (concentric, eccentric, segmental, quadrant-edge), flow direction, tap style, anticipated operating conditions, and any special marking or documentation you require. If you prefer, we’ll size the bore from your process data and provide a recommendation aligned with API 14.3/ISO 5167 methodology.
Customization Options
Every application is unique. We can tailor:
- Alternate alloys and coatings for corrosion, erosion, or temperature resistance.
- Special edge treatments (e.g., quadrant radius) and custom bevel angles.
- Enhanced flatness or parallelism for demanding gasket/seal requirements.
- Engraved or stamped identification to match plant standards.
- Surface finishes other than 30 RMS when specified by procedure or test plan.
Handling, Maintenance & Lifecycle
Orifice plates are measurement instruments and sealing components. We recommend handling them with clean gloves, protecting edges from nicks, and storing plates in protective sleeves or cases. During routine maintenance, inspect the upstream edge for wear or rounding, confirm the bore is free of deposits, and verify orientation marks remain legible. When process conditions change significantly—such as fluid properties or turndown requirements—consider a re-evaluation of the bore to maintain accuracy and signal strength.
Why Choose Our Plates
- Standards-Driven Accuracy: Built to meet or exceed API 14.3, ISO 5167, and ISA RP3.2.
- Reliable Materials: 304 and 316 stainless steel in stock, with other alloys available.
- Precision Machining: Consistent 30 RMS finish as standard, with tight control of bore and edge quality.
- Ease of Use: Clear identification, proper orientation markings, and straightforward installation.
- Responsive Support: Engineering assistance for plate selection, documentation, and customization.
Put Our Experience to Work
Whether you need a single replacement plate or a full set for a new measurement program, our team is ready to help. Share your size, ANSI rating, thickness, bore diameter, and material, and we’ll deliver a plate that integrates seamlessly with your orifice flanges and measurement approach. If you’d like us to recommend the bore, send your process conditions, and we’ll size it to the standards you specify. Our goal is simple: provide paddle-type orifice plates that install easily, perform predictably, and serve reliably across the life of your system.