Orifice Plates Unions & RTJ Plate Holders
Precision orifice plates for flow measurement and flow restriction, engineered to ASME, AGA, ISA, API, and AWWA standards. From Series 500 universal plates to restriction orifice unions, we stock the widest selection for fast delivery worldwide.
Orifice Plates & Unions
Series 500, 520, 560 & 590 plates and restriction orifice unions that meet or surpass AGA, ISA, ANSI, ASME, API, and AWWA standards. Stocked in 304 & 316 stainless, 1/8" and 1/4" thick, and custom made in any material and thickness.
Need a Bore Calculation? We'll Run It.
An orifice plate only measures as well as its bore. Our in-house team of professional mechanical engineers runs fast, accurate bore sizing for your application for an additional fee. Already know your bore size? We'll machine to it directly.
Bore Calculation Service
- Send Your Process DataLine size, flow rate, fluid properties, and the pressure differential you need.
- Our Engineers Size the BoreWe calculate the bore diameter and the downstream 45° bevel for your application.
- We Machine the PlateYour plate is bored and beveled to the calculation and shipped.
Why Orifice Plates
Choosing the Right Orifice Plate
Selection depends on your application: flow measurement or flow restriction, face type, and pressure rating. Compare the product lines below, or call our team to confirm before you order.
| Product Line | Type | Primary Use | Standards |
|---|---|---|---|
| Series 500 Universal Plates | Concentric bore orifice plate | General flow measurement. The most common configuration for liquids, gases, and steam. | AGA, ISA, ASME |
| Series 520 Paddle Type Plates | Paddle-style plate with handle | Flow measurement with easy removal and insertion, common in metering runs that need periodic access. | AGA, ISA, ASME |
| Series 560 & 590 RTJ Plates | Ring type joint holder plates | High-pressure metering runs that need RTJ flange connections. | ASME B16.36, API |
| Restriction Orifice Unions | Threaded union with integral restriction | Flow restriction: controlling or limiting flow rate rather than measuring it. | ASME, API |
Not Sure What You Need?
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 bore, it creates a measurable pressure drop across the plate. Using Bernoulli's equation, that differential converts to an accurate flow rate, making the orifice plate one of the simplest and most widely used flow measurement devices in industrial piping.
Measurement vs. Restriction
Bore Sizing & Calculation
An orifice plate is only as accurate as its bore. The bore diameter is calculated from pipe size, expected flow rate, fluid properties (density, viscosity, pressure, temperature), and the desired pressure differential. The bore edge typically needs a 45° bevel on the downstream side to keep flow characteristics accurate.
Match the Plate to the Process
Choose a material compatible with the process fluid and operating temperature to prevent corrosion and keep measurements accurate over time.
The Manufacturer, Not a Distributor
We make orifice plates and restriction orifice unions in Texas, Louisiana, and Oklahoma, so you get faster lead times, custom capabilities, and direct engineering support.
- Series 500, 520, 560 & 590 and restriction orifice unions stocked in 304 & 316 SS
- 1/8" and 1/4" thick in stock; custom thicknesses and alloys available
- In-house bore sizing by professional mechanical engineers
- Meets or exceeds AGA, ISA, ANSI, ASME, API, and AWWA standards
- ISO 9001:2015 certified manufacturing
- 24/7/365 emergency availability: Houston TX, Corpus Christi TX, Prairieville LA, Broken Arrow OK
Get an Orifice Plate Quote
Tell us your line size, flow data, and material, and we'll respond the same business day.
- Product line and line size
- Flow data, or your required bore size
- Material and thickness
- Quantity and date needed
| Specification | Details |
|---|---|
| Product Lines | Series 500 • 520 • 560 & 590 • Restriction Orifice Unions |
| Stocked Material | 304 / 316 SS |
| Stocked Thickness | 1/8" • 1/4" |
| Custom Options | Any alloy and thickness |
| Standards | AGA • ISA • ANSI • ASME • API • AWWA |
| Bore Sizing | In-house engineering (additional fee) |
| Shipping | Worldwide |
| Certification | ISO 9001:2015 |
| Emergency | 24 / 7 / 365 |
Why Choose USA Industries
From pipe blinds to heat exchanger tools, we deliver custom-engineered products with the fastest turnaround times in the industry.
Fastest Turnaround
Available 24/7 - 365 days a year with same-day shipping available on stock items. Custom orders in days, not weeks.
Direct Pricing
No middlemen markup. Buy direct from the manufacturer with 40+ years of industry excellence and save.
Custom Engineering
Custom solutions designed to your exact specifications.
ISO Certified Quality
A quality driven ISO 9001:2015 certified manufacturer ensures consistent excellence.
BBB A+ Rated
The highest grade awarded, signifying USAI operates with high integrity and a strong commitment to resolving customer issues.