Product Overview
The Preso Gemini cone is Badger Meter’s self-conditioning DP element — the fix for cramped piping. A centered cone re-shapes the velocity profile as flow passes through it, creating a differential pressure proportional to flow while doing its own conditioning, so it holds ±0.5% of actual flow in as little as 0–3 pipe diameters of upstream straight run where a pitot or Venturi run will not fit. There are no moving parts and minimal wear at the cone edge, and it carries ±0.1% repeatability over a 10:1-or-better turndown. The cone spans 0.5–24 in. lines over a 0.40–0.80 beta range for clean liquid, gas or steam, in flanged, wafer, butt-weld, socket-weld and threaded NPT styles, built in 304 / 304L or 316 / 316L stainless or A106 carbon steel on RF flanges rated 150–900#. Pair it with the DP transmitter of your choice.
Key Features & Benefits
- Self-conditioning — minimal straight run — the cone does its own flow conditioning, so a meter run of just 0–3 diameters before it is enough
- ±0.5% of actual flow — with ±0.1% repeatability and a turndown of 10:1 or better
- No moving parts, low wear — measurement comes from a fixed cone, with little wear at the cone edge over service life
- Wide installation envelope — 0.5–24 in. lines across a 0.40–0.80 beta range
- Multiple body styles — flanged, wafer, butt-weld, socket-weld and threaded NPT process connections
- Stainless or carbon-steel build — austenitic 304 / 304L or 316 / 316L stainless or A106 carbon-steel bodies, on raised-face flanges to 900#
- Liquid, gas or steam — one cone element across all three phases
Specifications
- Measurement principle
- Gemini cone — a centered cone that re-shapes the velocity profile and creates a differential pressure proportional to flow; because it conditions the profile itself it needs very little straight run, and there are no moving parts, with minimal wear on the cone edge.
- Accuracy
- ±0.5% of actual flow
- Repeatability
- ±0.1%
- Turndown (rangeability)
- 10:1 or better
- Line sizes
- 0.5–24 in.
- Max pressure / temperature
- Pressure per flange class — RF flange 150–900#
- Compatible fluids
- Clean liquid, gas or steam
- Connection styles
- Flanged (1–24 in.), wafer (1–4 in.), butt-weld (0.5–24 in.), socket-weld (0.5–2 in.) and threaded NPT (0.5–2 in.)
- Materials
- 304 / 304L or 316 / 316L stainless, or A106 carbon-steel body
- Beta ratio
- 0.40–0.80
- Straight-run requirement
- Typically 0–3 pipe diameters upstream / 0–1 downstream — the answer for tight piping
Common Applications
- Tight piping where there is little straight run before the meter run
- Retrofit into runs with no room for a pitot or Venturi installation
- Clean liquid, gas and steam metering
- Compact installations and packaged skids
- Small- to mid-line process flow, 0.5–24 in.
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 Gemini Cone:
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.