Product Overview
The Preso Coin segmented wedge is Badger Meter’s dirty-service DP element: a V-shaped restriction that creates a differential pressure proportional to flow while sweeping solids through the line instead of trapping them. That geometry keeps it accurate on slurries, abrasives and viscous fluids to 3,000+ cP, and it stays linear at low Reynolds numbers (down to about 300) where a pitot or orifice would foul or stall. It spans 0.5–40 in. lines to 800°F and ships in butt-weld, flanged, wafer (PCOW) and bidirectional back-to-back (PCB) styles, with Chem-Tee taps for the worst fouling duty. Accuracy is ±3% uncalibrated or ±0.5% calibrated, at ±0.2% repeatability over a 10:1 turndown. The trade-off is permanent pressure loss higher than a pitot or Venturi — the price of an element that does not clog.
Key Features & Benefits
- Self-cleaning V-restriction — the wedge sweeps solids and sediment downstream rather than building up at the element, so it holds its reading on fouling service
- Accurate at low Reynolds numbers — holds its calibration down to about Re 300, where viscous and slurry flows defeat a pitot or orifice
- Viscous-fluid capable — measures thick fluids to 3,000+ cP
- Bidirectional option — the PCB back-to-back style reads flow in either direction from one compact body with flange-integral taps
- Code-compliant construction — built to ASME, ANSI B31.1 and NACE MR-0175 where the project calls for it
- Wide install range — 0.5–40 in. lines to 800°F, in butt-weld, flanged, wafer and back-to-back styles
Specifications
- Measurement principle
- Segmented-wedge element — a V-shaped restriction set across the bore; the differential it generates tracks flow, while the open throat below the apex passes solids rather than collecting them. Built for dirty, abrasive and slurry service.
- Accuracy
- ±3% uncalibrated; ±0.5% calibrated
- Repeatability
- ±0.2%
- Turndown (rangeability)
- 10:1
- Line sizes
- 0.5–40 in.
- Max pressure / temperature
- To 800°F; pressure per flange class (RF 150–900#)
- Compatible fluids
- Dirty, abrasive, slurry and fouling liquids; viscous fluids to 3,000+ cP; stays linear in low-Reynolds flow (to about Re 300)
- Connection styles
- Butt-weld; flanged (RF 150–900#); Chem-Tee taps for slurry / fouling; NPT pressure taps; PCOW wafer (0.5–4 in., narrow face-to-face); PCB back-to-back (bidirectional, compact, with flange-integral taps)
- Materials
- Carbon steel, 304 SS or 316 SS body and throat (specify-other on request)
- Permanent pressure loss
- Higher than a pitot or Venturi — a wedge / orifice-type element
Common Applications
- Slurries and solids-laden liquids that would clog or erode other DP elements
- Abrasive and fouling process streams
- Low-Reynolds and high-viscosity flows
- High-temperature dirty lines to 800°F
- Bidirectional flow measurement (PCB back-to-back)
- Mining, wastewater and heavy process service
Design & Selection Considerations
- A primary element, paired with your transmitter — Preso supplies the DP primary element — the shaped obstruction that creates a pressure drop proportional to flow (flow tracks the square root of ΔP). You pair it with the DP transmitter and readout of your choice. One technology covers liquid, gas and steam, with no moving parts in the line.
- Choose the element by fluid, size, loss and straight run — the Ellipse averaging pitot is the low-loss insertion choice for clean fluids in large lines; a Venturi gives high accuracy with strong pressure recovery; the Coin segmented wedge handles dirty, abrasive and slurry service; the Gemini cone conditions the flow itself for tight piping. Start from the fluid and the pipe, not the model number.
- Mind the permanent pressure loss — every DP element leaves some unrecovered pressure loss that costs pumping energy over the life of the line. The averaging pitot has the lowest loss (it only samples the flow); a Venturi recovers most of its pressure; segmented-wedge and orifice-type elements run higher. Use the input form to tell us how much loss you can give up and it steers the choice.
- Match the element to the straight run you have — averaging-pitot and Venturi elements need upstream straight run to settle the flow profile. Where the piping is cramped, the Gemini cone conditions the flow as it passes and holds accuracy in as little as 0–3 pipe diameters upstream. If straight run is short, say so up front and the selection moves toward the cone.
- DP excels on steam, high temperature and high pressure — with no moving parts in the line, a DP element is often the most practical primary device for large, hot or high-pressure lines and for steam. The Ellipse handles up to about 800°F and 800 psi with dedicated steam variants; Venturi tubes and nozzles suit large high-pressure liquid, gas and steam. For saturated or superheated steam and process gas in big or hot lines, DP earns its place.
- Dirty, abrasive or slurry service → the segmented wedge — the Coin segmented wedge’s V-shaped restriction sweeps solids through instead of trapping them, staying accurate at low Reynolds numbers (down to about 300) and to 800°F — conditions that foul or erode a pitot or orifice. Averaging-pitot and Venturi elements are for cleaner fluids.
- Specify calibration and certifications up front — every element can ship with a factory 6-point ±0.5% flow calibration, 3- or 5-valve instrument manifolds, hardcoating for abrasive duty, and traceable material certifications — NACE MR-0175 / MR-0103, PMI, hydrostatic, and radiographic / magnetic-particle / dye-penetrant (NDE) examination, specified at time of quote. List the certs your project requires and they are built into the order.
To size & select the right Preso Coin Segmented Wedge:
Use the input form to tell us the line size, fluid, temperature and pressure, the straight run you have, and any material or NDE certifications — and we’ll spec the element, factory 6-point calibration, instrument manifolds and certifications for your application. Preso DP elements are engineered to your line, so each is quoted to specification.
Flow Meter Application Sheet ›Talk to an engineer directly — Scott Prater, Principal · 917-580-0878 · scott@pratertechnical.com
Specifications compiled by Prater Technical Partners from Badger Meter Preso differential-pressure flow-element datasheets.