Series 520
Paddle Type Plates
CNC
MACHINING
- Line Size
- Plate Thickness
- Bore Size
- Bevel / No Bevel
- Material Type (Stainless Steel - 304, 316, Other)
- Quantity Needed
- Necessary Delivery Date
| Product Features & Specifications | |
|---|---|
| Meets or exceeds AGA, ISA, ANSI, ASME & API standards | |
| Precision CNC machining for superior accuracy and quality control | |
| Simple to use and easy to troubleshoot | |
| Minimal maintenance required | |
| Stocked materials: 304/316 Stainless Steel — available in any alloy upon request | |
| Fast and accurate orifice bore calculation services available | |
| Custom coatings available upon request | |
Produced on cutting-edge CNC machines by trained mechanical engineers and skilled CNC operators — our Series 520 Paddle-Type Orifice Plates adhere to the strictest manufacturing processes and achieve optimal accuracy standards for differential pressure flow measurement.
NEED A BORE CALCULATION?
Let USA Industries' engineers calculate the correct bore size based on process data for the project.
What Is a Paddle-Type Orifice Plate?
A paddle-type orifice plate — Series 520 — is a thin, precision-machined plate with a circular bore at its center, installed between a pair of raised face orifice flanges to create a calibrated restriction in a pipeline. As fluid passes through the bore, it creates a measurable pressure differential across the plate, which is read by a flow meter or transmitter to calculate flow rate. The "paddle" design includes an extended handle, allowing the plate to be installed and removed from the flange assembly without fully separating the pipeline — making inspection, cleaning, and bore changes fast and straightforward.
Series 520 plates are machined on CNC equipment to meet AGA, ISA, ANSI, ASME, and API standards for differential pressure flow measurement, and are stocked in 304 and 316 stainless steel with custom alloys and coatings available on request.
Get an Orifice Plate Quote
Tell us your line size, flange rating, bore type, and material — we'll respond same business day.
Get A Quick Quote 📞 (800) 456-8721Quick Specs
How Orifice Plates Measure Flow
Orifice plate flow measurement works on a simple principle: when fluid is forced through a smaller opening, its velocity increases and its pressure drops. By precisely machining the orifice bore to a known diameter and measuring the pressure difference between the upstream and downstream sides of the plate, flow rate can be calculated to a high degree of accuracy.
- Upstream pressure tap — Measures line pressure before the fluid passes through the bore
- Bore restriction — A precisely sized opening creates a controlled pressure drop
- Downstream pressure tap — Measures the reduced pressure after the bore
- Differential pressure transmitter — Converts the pressure difference into a flow rate reading
Because the relationship between bore size, pressure differential, and flow rate is well-documented in AGA and ISA standards, orifice plates remain one of the most widely used and cost-effective flow measurement devices in the industry.
Bore Types Compared
The bore geometry is selected based on the fluid type, line condition, and measurement accuracy required. USA Industries manufactures all four standard bore types:
| Bore Type | Description | Best For |
|---|---|---|
| Concentric | Bore centered on the plate — the most common configuration | Clean, single-phase fluids (gas, liquid, steam) under normal flow conditions |
| Eccentric | Bore offset toward the top or bottom of the plate | Fluids carrying entrained solids, condensate, or gas bubbles that need to pass beneath or above the bore |
| Quadrant Edge | Rounded (quarter-circle) upstream edge instead of a sharp edge | Low Reynolds number / high-viscosity flows where a sharp-edged bore would be unreliable |
| Segmental | Bore is a segment (partial circle) rather than a full circle, set at the bottom or top of the pipe | Slurries, dirty fluids, or two-phase flow where debris or liquid needs an unobstructed path |
Not sure which bore type fits your application? Call our team or use our Bore Calculation Form and our engineers will confirm the correct bore type and size for your process conditions.
Choosing the Right Flange Rating & Thickness
Series 520 paddle orifice plates are manufactured to match the flange rating of your existing piping system — from 150# through 2500#. Use the interactive flange rating selector above to find the line size (A), handle length (HL), handle width (HW), and plate thickness (T) for your specific rating.
- Lower pressure classes (150#–300#) — Standard 1/8" to 1/4" plate thickness covers most line sizes
- Mid-range classes (400#–900#) — Plate thickness increases with line size to maintain rigidity under higher differential pressure
- High pressure classes (1500#–2500#) — Thicker plates and shorter handle lengths are standard; larger sizes (22"+) may not be available in 900# and above — call to confirm availability for your size
If your application requires a non-standard thickness, bore size, or bevel configuration, USA Industries can manufacture to your exact specification — just provide your process data and our engineers will confirm the correct plate design.
Material & Coating Options
The plate material should be compatible with the process fluid and line material to prevent corrosion and ensure long-term measurement accuracy.
- 304 & 316 Stainless Steel — Standard stocked materials; corrosion-resistant and suitable for most process fluids
- Monel, Hastelloy, Copper-Nickel — Available for highly corrosive or specialty chemical service
- Custom alloys — Manufactured to your specification for unique process requirements
- Custom coatings — Available upon request for additional corrosion or wear resistance
Why Choose USA Industries for Orifice Plates?
USA Industries manufactures Series 520 paddle-type orifice plates on cutting-edge CNC equipment, with every plate produced and inspected in-house from our facilities in Texas, Louisiana, and Oklahoma.
- Precision CNC machining — meets AGA, ISA, ANSI, ASME & API standards
- Stocked in 304/316 stainless steel — any alloy available upon request
- All four bore types — concentric, eccentric, quadrant, and segmental
- Fast, accurate bore calculation services from trained mechanical engineers
- Custom coatings, thicknesses, and bevels manufactured to spec
- In-stock items ship within 24 hours — same-day local delivery available in Texas
- ISO 9001:2015 certified manufacturing
- 24/7/365 emergency availability — Houston TX, Corpus Christi TX, Prairieville LA, Broken Arrow OK
Orifice Plates
Select Flange Rating to See Specifications
All sizes in inches • Additional sizes available
Orifice Plates
Frequently Asked Questions
Yes, we typically use the bore calculations provided to us by the customer, but we can do the bore calculations upon request for a small additional fee.
Yes, our four bore options are concentric, eccentric, quadrant and segment.
Yes, we're happy to engineer in a vent or drain. Let us know your specs and we'll manufacture it to meet your exact needs.
Yes, we can completely customize your orifice plates to your unique needs.
We stock our orifice plates in 304 & 316 stainless steel, but they are available in any material requested. We have produced orifice plates for clients in everything from monel to hastelloy to copper-nickel alloys and more!
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.