& RTJ Plate Holders
USA Industries manufactures precision orifice plates for flow measurement and flow restriction applications — engineered to ASME, AGA, ISA, API, and AWWA standards. From Series 500 universal plates to Series 520 paddle type plates, RTJ holder plates, and restriction orifice unions, we stock the widest selection for fast delivery worldwide.
We produce Series 500 Universal Orifice Plates, Series 520 Paddle Type Plates, Series 560 and 590 Ring Type Joint (RTJ) Holder Plates, and Restriction Orifice Unions that meet or surpass AGA, ISA, ANSI, ASME, API, and AWWA standards. Stock includes plates in 304 & 316 stainless steels, with thickness options of 1/8" and 1/4".
Note: Custom manufacturing is available for plates in any material and thickness. Our in-house team of professional mechanical engineers can provide bore sizing calculation services for an extra fee if needed.
USA Industries — Orifice Plate Line Sheet
Product Reference Document- ✓Flow Measurement: Measure fluid flow rate in pipelines by constricting the flow path to create a pressure drop — flow rate can be calculated using Bernoulli's equation.
- ✓Cost-Effective: Simple, inexpensive, and reliable compared to other flow measurement devices.
- ✓Easy Installation & Maintenance: Easily integrated into pipelines with minimal upkeep and quick replacement.
- ✓Wide Compatibility: Suitable for liquids, gases, and steam across oil & gas, chemical processing, water treatment, and HVAC.
- ✓Standardized Design: Meets API and ISO guidelines for consistency and reliability.
- ✓In-house team of professional mechanical engineers runs your calculations.
- ✓Fast, accurate orifice bore sizing for your specific application.
- ✓Bore must be accurately sized and beveled for optimal plate performance.
- ✓Service available for an additional fee — contact us to get started.
Choosing the Right Orifice Plate
Orifice plate selection depends on your application — flow measurement versus flow restriction, face type, and pressure rating. Use the comparison table and quick finder below to identify the right product line before you order, or call our team to confirm.
Product Line Comparison
| Product Line | Type | Primary Use | Standards | Available |
|---|---|---|---|---|
| Series 500 Universal Plates | Concentric bore orifice plate | General flow measurement — most common configuration for liquids, gases, and steam | AGA, ISA, ASME | ✓ |
| Series 520 Paddle Type Plates | Paddle-style orifice plate with handle | Flow measurement with easy removal/insertion — common in metering runs requiring periodic access | AGA, ISA, ASME | ✓ |
| Series 560 & 590 RTJ Plates | Ring Type Joint holder plates | High-pressure metering runs requiring RTJ flange connections | ASME B16.36, API | ✓ |
| Restriction Orifice Unions | Threaded union with integral restriction | Flow restriction — controlling/limiting flow rate rather than measuring it | ASME, API | ✓ |
What Is an Orifice Plate?
An orifice plate is a thin, flat plate with a precisely machined hole (the "bore") installed in a pipeline, typically between two flanges. As fluid flows through the restricted bore, it creates a measurable pressure drop across the plate. Using Bernoulli's equation, that pressure differential can be converted into an accurate flow rate — making the orifice plate one of the simplest and most widely used flow measurement devices in industrial piping.
Orifice plates are manufactured to AGA, ISA, ANSI, ASME, API, and AWWA standards, and are also used for flow restriction applications where the goal is to limit flow rather than measure it.
Measurement vs. Restriction
It's important to understand the two different applications orifice plates serve:
- Flow measurement — A precisely sized concentric, eccentric, or paddle-style bore creates a pressure drop that's measured by instrumentation on either side of the plate, then converted to a flow rate reading. Series 500 and Series 520 plates are designed for this purpose.
- Flow restriction — A smaller bore is used specifically to limit or throttle flow rate to a desired maximum, often for safety or process control reasons. Restriction Orifice Unions are purpose-built for this application and are not intended for precision flow measurement.
Bore Sizing & Calculation
The accuracy of any orifice plate depends entirely on the precision of the bore. The bore diameter must be calculated based on pipe size, expected flow rate, fluid properties (density, viscosity, pressure, temperature), and the desired pressure differential. The bore edge typically requires a 45° bevel on the downstream side to maintain accurate flow characteristics.
USA Industries' in-house team of professional mechanical engineers offers bore sizing calculation services for an additional fee — providing fast, accurate sizing so your plate performs correctly from day one. If you already know your required bore size, we can manufacture to that specification directly.
Material Options
Orifice plates should be manufactured from a material compatible with the process fluid and operating temperature to prevent corrosion and ensure measurement accuracy over time.
- 304 Stainless Steel — Standard stocked material for general flow measurement applications
- 316 Stainless Steel — Enhanced corrosion resistance for more aggressive process fluids
- Carbon Steel — Available for compatible service conditions
- Duplex & Super Duplex Stainless — High strength and corrosion resistance for demanding environments
- Monel, Inconel, Hastelloy, Titanium — Available for extreme temperature or highly corrosive service
- Custom alloys & thicknesses — Any material and thickness available on request, beyond the stocked 1/8" and 1/4" options
Why Choose USA Industries Orifice Plates?
USA Industries manufactures orifice plates and restriction orifice unions from our facilities in Texas, Louisiana, and Oklahoma. As the manufacturer — not a distributor — we offer faster lead times, custom capabilities, and direct engineering support.
- Stock includes Series 500, 520, 560 & 590, and Restriction Orifice Unions in 304 & 316 SS
- Standard thicknesses of 1/8" and 1/4" in stock; custom thicknesses and alloys available
- In-house bore sizing calculation service by professional mechanical engineers
- Meets or exceeds AGA, ISA, ANSI, ASME, API, and AWWA standards
- ISO 9001:2015 certified manufacturing
- We ship worldwide — fast turnarounds, large inventory
- 24/7/365 emergency availability — Houston TX, Corpus Christi TX, Prairieville LA, Broken Arrow OK
Orifice Plates
