Series 520 Paddle Type Orifice Plates
For raised face orifice flanges and holding blocks. CNC machined by trained mechanical engineers and skilled operators to AGA, ISA, ANSI, ASME, and API standards, in all four bore types. Need the bore sized? Our engineers will calculate it for you.
Need a Bore Calculation? We'll Run It.
An orifice plate only measures as well as its bore. Send us your process data and our trained mechanical engineers will calculate the correct bore type, size, and bevel, quickly and accurately, for a small fee. Then we machine the 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 and bevel for your application.
- We Machine the PlateYour plate is bored and beveled to the calculation and shipped.
Get a Quote or Order
Send us these details and we'll respond the same business day.
- Line size and flange rating
- Plate thickness
- Bore type and size (or request a bore calculation)
- Bevel or no bevel
- Material (304 SS, 316 SS, or other)
- Vent or drain, if needed
- Quantity and date needed
| Specification | Details |
|---|---|
| Use With | Raised face orifice flanges • Holding blocks |
| Flange Ratings | 150# • 300# • 400# • 600# • 900# • 1500# • 2500# |
| Bore Types | Concentric • Eccentric • Quadrant • Segmental |
| Stocked Materials | 304 SS • 316 SS (any alloy on request) |
| Other Alloys | Monel • Hastelloy • Copper-Nickel • More |
| Machining | Precision CNC |
| Options | Custom thickness • Bevel • Vent or drain • Coatings |
| Bore Sizing | Bore calculation service available (small additional fee) |
| Maintenance | Minimal |
| Shipping | In-stock items ship within 24 hours (same-day local delivery in Texas) |
What Is a Paddle Type Orifice Plate?
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 the line. Fluid passing through the bore creates a measurable pressure differential that a flow meter or transmitter reads to calculate flow rate.
The extended paddle handle lets you install and remove the plate without fully separating the pipeline, so inspection, cleaning, and bore changes are fast.
Also known as:
How Orifice Plates Measure Flow
Force fluid through a smaller opening and its velocity rises while its pressure drops. Machine the bore to a known diameter, measure the pressure on each side, and flow rate can be calculated to a high degree of accuracy.
- Upstream Pressure TapMeasures line pressure before the fluid passes through the bore.
- Bore RestrictionA precisely sized opening creates a controlled pressure drop.
- Downstream Pressure TapMeasures the reduced pressure after the bore.
- DP TransmitterConverts 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
Bore geometry depends on the fluid, the line condition, and the accuracy you need. We manufacture all four standard bore types.
Flange Rating & Thickness
Series 520 plates are made to match your flange rating, 150# through 2500#. Use the flange rating selector below for line size (A), handle length (HL), handle width (HW), and plate thickness (T).
Need a non-standard thickness, bore, or bevel? Send your process data and our engineers will confirm the plate design.
Material & Coating Options
Match the plate to the process fluid and line material to prevent corrosion and protect measurement accuracy.
Made, Bored & Inspected In-House
Every Series 520 plate is CNC machined and inspected in-house, with 24/7/365 emergency service from Houston TX, Corpus Christi TX, Prairieville LA, and Broken Arrow OK.
Select a Flange Rating
All sizes in inches. Additional sizes available.
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.