Restriction Orifice Unions
One-piece stainless steel orifice plates shaped to the union seat, ball to cone, so no gaskets are needed. Precision CNC machined, simple to use, and easy to troubleshoot. Need the bore sized? Our engineers will calculate it for you.
*6,000 PSIG available on request.
Need a Bore Calculation? We'll Run It.
A restriction orifice only controls flow as well as its bore is sized. Send us your process data and our staff engineers will calculate the correct bore size, quickly and accurately, for a small fee. Then we bore the union plate to match.
Bore Calculation Service
- Send Your Process DataFill out the bore calculation form for your project.
- Our Engineers Size the BoreWe calculate the correct bore size for your application.
- We Machine the PlateYour union plate is bored to the calculation and shipped.
Precise Flow Control, No Gaskets
Applications:
Get a Quote or Order
Send us these details and we'll respond the same business day.
- Line size (1/4" to 2")
- Connection: female NPT or socket weld
- Body: carbon or stainless steel
- Pressure rating (3,000 or 6,000 PSIG)
- Plate type: recessed, pressed, or tabbed
- Bore size (or request a bore calculation)
- Quantity and date needed
Restriction Orifice Union Dimensions
| SizePipe Size | ADim. A | BDim. B | CDim. C |
|---|---|---|---|
| 1/4" | 1-3/4" | 1/4" | 1-3/8" |
| 3/8" | 1-7/8" | 3/8" | 1-5/8" |
| 1/2" | 2" | 1/2" | 1-3/4" |
| 3/4" | 2-1/4" | 3/4" | 2-3/16" |
| 1" | 2-9/16" | 1" | 2-9/16" |
| 1-1/4" | 2-7/8" | 1-1/4" | 3-1/16" |
| 1-1/2" | 3-1/8" | 1-1/2" | 3-7/16" |
| 2" | 3-1/2" | 2" | 4" |
All dimensions in inches. Chart DS-ROU-001. ASME compliant.
Restriction Orifice Union FAQ
Can you determine what bore size I need?
Yes. We usually work from the bore calculations you provide, but our engineers can run them for a small additional fee. Request a bore calculation.
Can I buy just the orifice plates for my unions?
Yes. We sell all three plate types, bored to your specs or as blanks.
Are the unions rated only for 3,000#?
No. 6,000# is also available on request.
Which orifice plate option is right for my union?
It depends on your application, and the choice is yours to make. Recessed, pressed, and pressed with tab are all available.
Can I get NPT or socket weld connections?
Yes. Female NPT and socket weld are both available.
What materials are available for the plates?
We stock 304 and 316 stainless steel, and make plates in any material requested, from monel to hastelloy to copper-nickel alloys and more.
Can you apply custom coatings?
Yes. We regularly coat orifice plates. Tell us what you need.
How quickly can I get restriction orifice unions?
In-stock items ship within 24 hours. As the manufacturer, we can also customize or rush an order through our facility, and with large in-stock inventories we can hit almost any deadline.
Why USA Industries?
40+ years of manufacturing excellence and innovation
Fastest Turnaround
Same-day shipping available on stock items. Custom orders in days, not weeks.
Manufactured In-House
U.S. produced steel, PMI verified, QC certified.
ISO 9001:2015 Certified
Quality-driven manufacturing process ensures excellence.
Engineering Innovation
Precision-Engineered Industrial Solutions — Delivered Fast!
100% USA Materials
All raw materials sourced from American mills.