Product Overview
The Preso Ellipse averaging pitot tube (industrial grade) is Badger Meter’s low-loss insertion DP element for clean liquid, gas and steam in large lines. A multi-port probe averages the velocity profile across the pipe to create a differential pressure proportional to flow, holding ±0.75% of reading at ±0.1% repeatability over a 17:1 turndown. Because it only samples the flow (drag coefficient ≤0.32), it leaves the lowest permanent pressure loss of any DP element — and it spans 2–72 in. pipes to about 800 psi / 800°F through a single-point pipe entry. It ships as compression and flanged (AR/AF) and as steam-rated (AS/ASF/AHS) models, with hot-tap (AHL/AHF/AHZ) and low-pressure wet-tap (AHR) variants for insertion into live, pressurized lines. The 316/316L SS sensor takes Monel, Inconel or Hastelloy probe options for aggressive service. Pair it with the DP transmitter of your choice; factory flow calibration, instrument manifolds, hardcoating and NACE / PMI / NDE certifications are available to specification.
Key Features & Benefits
- Lowest permanent pressure loss — a slim insertion probe leaves the line essentially unobstructed, so almost no pumping energy is spent on the meter
- Hot-tappable — AHL / AHF / AHZ hot-tap and AHR wet-tap models install or service under pressure, with no shutdown
- ±0.75% of reading — at ±0.1% repeatability across a 17:1 turndown
- Large-line range — 2–72 in. pipes to about 800 psi / 800°F
- Steam-ready variants — dedicated AS / ASF / AHS models for saturated and superheated steam
- Single-point pipe entry — one penetration carries DP, temperature and static-pressure sensing
- No moving parts — one element technology across liquid, gas and steam, for long, trouble-free service
Specifications
- Measurement principle
- Averaging pitot tube — a multi-ported, self-averaging insertion probe that averages the velocity profile across the pipe to create a differential pressure proportional to flow; the lowest-loss DP element, installed through a single-point pipe entry.
- Accuracy
- ±0.75% of reading
- Repeatability
- ±0.1% of reading
- Turndown (rangeability)
- 17:1, with no vacuum effect
- Line sizes
- 2–72 in. (AHS / AHS1 threaded models 2–24 in.; AHZ flanged covers the larger sizes)
- Max pressure / temperature
- Up to 800 psi / 800°F (consult factory above these)
- Compatible fluids
- Clean liquid, gas or steam (including saturated and superheated steam)
- Model variants
- AR / AF (compression & flanged, non-hot-tap); AHL / AHF / AHZ (hot-tap threaded & flanged); AS / ASF / AHS (steam); AHR (low-pressure wet-tap)
- Connection styles
- Compression, flanged, hot-tap and wet-tap; 1/2 in. FNPT or socket instrument connection; optional integral 3- or 5-valve transmitter-mount manifold and integral RTD
- Materials
- 316/316L SS Ellipse sensor standard; carbon-steel weld fitting and packing chamber; Monel, Inconel or Hastelloy probe optional
- Straight-run requirement
- Upstream straight run required to settle the flow profile (amount depends on the upstream fittings); most accurate at pipe Reynolds number above 75,000
- Permanent pressure loss
- Lowest of the DP elements — the probe only samples the flow (drag coefficient 0.32 or less; typically about 3% of the DP in a 12 in. line)
Common Applications
- Large-line liquid, gas and steam flow in plants and utilities
- Low-pressure-loss measurement where pumping energy matters
- Hot-tap retrofit into existing pressurized lines
- Steam and high-temperature service (AS / AHS variants)
- Air-handling ducts, compressed-air and process-gas mains
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 Ellipse Averaging Pitot — Industrial:
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.