Averaging Pitot Tube Flow Meter
Hot-Tap Install, DN50 to DN6000+
±0.5 % of flow per ISO 5167 / GB/T 2624 conventions
PN0.6 to PN42 MPa working pressure, −200 to +800 °C medium
Approximately 5 % permanent ΔP loss vs orifice 50 to 65 %
- Insertion DP primary for cooling-water headers, main steam, HVAC chilled-water mains, compressed-air trunks, and stack / duct combustion gas
- Hot-tap retrofit on the live header: single penetration, no shutdown, no pipe-cut
- Transmitter-agnostic; pair with existing Rosemount 3051, Yokogawa EJA, or Honeywell ST3000 DP transmitter, or specify the factory-supplied DP transmitter
Multi-port averaging probe · hot-tap insertion · DP transmitter pairing
Single penetration, no shutdown, ~5 % permanent ΔP loss
The averaging pitot tube is the insertion DP primary element ProFlow Meters supplies for very-large-bore service and live-header retrofit. A multi-port averaging probe is pushed across the pipe bore through a single hot-tap penetration, sampling the velocity profile at multiple radial positions and integrating to a single differential-pressure signal. Any 4-20 mA HART DP transmitter reads it. The accuracy is ±0.5 % of flow per ISO 5167 / GB/T 2624 conventions used in AGA-3 / API 14.3 custody practice, the permanent pressure loss is approximately 5 % of dynamic head, and the scale runs DN50 to DN6000 standard with larger sizes by quote. Ships in 5–7 business days.
Benefits
- Hot-tap install on the live header: single penetration through an isolation gland, no pipe-cut, no system shutdown; the retrofit choice for power-station cooling-water and refinery utility mains.
- ±0.5 % of flow per ISO 5167 / GB/T 2624 conventions used in AGA-3 / API 14.3 custody practice; wet-flow factory-loop calibration certificate ships with each meter.
- Approximately 5 % permanent ΔP loss versus orifice 50 to 65 % and nozzle 30 to 40 %; the low-head choice for circulating cooling-water and HVAC mains.
- DN50 to DN6000 standard, larger by quote: scales to power-station main-steam, cooling-water headers, and stack / duct gas where electronic alternatives are capex-prohibitive.
- PN0.6 to PN42 MPa and −200 to +800 °C: covers superheated steam, hot flue gas, refinery hot oil, and cryogenic LNG / LH2 / LOX in one mechanical primary.
- Transmitter-agnostic DP pairing: reuse existing Rosemount 3051, Yokogawa EJA, Honeywell ST3000, or ABB 266 inventory, or specify the factory DP transmitter with 3-valve or 5-valve manifold.
- Lead time 5–7 business days from the factory; wetted-metal mill cert traceable to heat number ships with each meter.
Configure your build.
Pick DN, PN, probe material, connection, and DP transmitter option. Engineering replies with sized quote and beta-ratio within one business day.
Your Configuration
PF-LG-JS-300-2.5-316-F-N-N
DN300 averaging pitot tube primary element, PN2.5 MPa working pressure, 316 stainless probe, flange HG/T 20592 connection, primary only (buyer supplies DP transmitter).
Estimated unit price
Verified after engineering review & β-sizing
$1,800
✓ ISO 5167 / GB/T 2624 conformant primary
✓ Hot-tap valve adapter on welded-hub option
✓ Reply within 4 business hours
✓ Hot-tap valve adapter on welded-hub option
✓ Reply within 4 business hours
Typical applications
Four applications where the averaging pitot is the right pick.
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Power-station cooling-water headers
DN1000 to DN6000 condenser cooling-water mains where pump head is precious; the averaging pitot adds ~5 % permanent loss versus an orifice 50 % and retrofits without draining the loop.
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Main steam and superheated steam lines
Boiler outlet and high-pressure steam headers at PN10 to PN42 MPa and 450 to 540 °C; the 12CrMo or Cr5Mo probe holds full creep life on long-service steam service.
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HVAC chilled-water and district-energy mains
Campus and district-heat trunk headers from DN200 to DN1500 retrofit live, with the low ~5 % permanent loss protecting circulating-pump head and chiller plant efficiency.
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Stack flue gas and combustion-air ducts
Boiler primary and secondary combustion-air, induced-draft and forced-draft fans, and flue-gas stack survey on DN2000 to DN6000 ducts where no inline meter is economic and hot-tap insertion is the only retrofit path.
Specifications
| Measurement principle | Multi-port averaging pitot probe inserted across the pipe bore; multi-port sampling integrates the velocity profile to a single differential-pressure signal (Bernoulli + continuity); ΔP read by a separately mounted 4-20 mA HART DP transmitter |
|---|---|
| Accuracy | ±0.5 % of flow (primary element wet-cal); system accuracy also depends on DP-transmitter accuracy and ISO 5167 conformant install |
| Repeatability | ±0.1 % typical per ISO 5167 conformant install |
| Reference standards | Designed per ISO 5167 / GB/T 2624 conventions used in AGA-3 and API 14.3 custody practice |
| Permanent pressure loss | Approximately 5 % of dynamic head; lowest of any DP primary element (orifice 50 to 65 %, nozzle 30 to 40 %, classical venturi 10 to 15 %) |
| Turndown | 1:3 standard with 4-20 mA DP transmitter; 1:7 to 1:10 with HART smart DP transmitter (DP physics limit) |
| Line sizes | DN50 to DN6000 standard; larger sizes by quote (DN6000+ for stack / duct gas and main cooling-water headers) |
| Working pressure | PN0.6 / PN1.0 / PN1.6 / PN2.5 / PN4.0 / PN6.4 / PN10 / PN16 / PN25 / PN42 MPa |
| Medium temperature | −200 to +800 °C per probe material option (304 / 316 SS for ambient to 400 °C; 12CrMo and Cr5Mo for hot steam to 540 °C; high-grade alloys to +800 °C; cryogenic SS to −200 °C) |
| Probe material | 304 / 316 / 316L / 321 stainless steel; 1Cr18Ni9Ti; 12CrMo and Cr5Mo chrome-moly for hot-steam service; Hastelloy, Monel, Titanium for corrosive service |
| Process connection | Flange HG/T 20592 PN0.6 to PN42 MPa; ANSI 150 lb to 1500 lb; welded hub with hot-tap valve adapter for DN1000 and larger |
| Installation mode | Hot-tap retrofit through an isolation gland on the live header (signature install) or shutdown insertion through a flanged process connection on a new-build |
| Applicable media | Clean liquid, clean gas, saturated and superheated steam, natural gas, refined oil, cryogenic liquids (LNG, LN2, LOX, LH2); single-phase, full-pipe flow |
| DP transmitter pairing | Buyer-supplied Rosemount 3051, Yokogawa EJA, Honeywell ST3000, ABB 266, or any 4-20 mA HART DP transmitter; factory-supplied DP transmitter option pairs a 3051-class smart transmitter with 3-valve or 5-valve impulse-line manifold |
| DP transmitter output | 4-20 mA / HART / RS-485 Modbus RTU (transmitter-driven, separately specified) |
| Hazardous-area option | Ex d IIC T6 Gb on DP-transmitter housing; the primary element itself is passive mechanical with no electronics and Ex-exempt |
| Ingress protection | IP65 standard on DP-transmitter housing; IP66 / IP67 by special order |
| Calibration | Wet-flow factory-loop calibration; ISO 9001 calibration certificate; cert traceable to national flow standard; mill cert traceable to heat number on wetted-metal grade |
| Power supply (DP transmitter) | 24 VDC, 4-20 mA loop-powered (2-wire); 220 VAC for separately-housed signal converter on integrated build |
| Lead time | 5–7 business days from factory |
Installation
Five field rules for hot-tap insertion and a stable DP signal.
- Hot-tap valve and isolation gland welded or flanged to the live header A hot-tap valve and packing gland are first fitted to the host pipe at the chosen install point with the line still pressurized. A third-party hot-tap drilling contractor then drills the wall through the closed valve, the cut is retracted, the valve is closed, and the system is ready for probe insertion. The line never sees a shutdown.
- Probe insertion across the full pipe bore The averaging pitot probe is passed through the isolation gland and the open hot-tap valve, then pushed to its sized insertion depth across the pipe bore. The packing gland is tightened against the probe shaft to seal against working pressure. The probe orientation matches the flow direction with the high-side ports facing upstream.
- Upstream and downstream straight pipe per ISO 5167 Allow at least 22 pipe diameters upstream and 5 diameters downstream of any 90° elbow, tee, valve, or reducer (more upstream behind two elbows out-of-plane or a control valve). Less straight-pipe yields a swirling velocity profile and the multi-port averaging integral sees a biased reading. Use a flow conditioner if the layout cannot give the required run.
- Impulse-line routing to the DP transmitter 8 to 12 mm OD stainless tubing connects the high-side and low-side ports on the probe head to the DP transmitter. Route with continuous slope (1:10 minimum) downward to the transmitter on liquid service, upward to the primary on gas service. Provide isolation valves at the probe and a 3-valve or 5-valve equalizing manifold at the transmitter. Total impulse-line length should stay under 5 m to minimize lag.
- Zero-cal at commissioning with the line pressurized and flow stopped After install, with the line pressurized but flow stopped and the manifold equalizing valve open, the DP transmitter is zeroed and the offset recorded for service-life trend analysis. Isolation valves are then opened, the equalizing valve is closed, and the loop is in service. Re-zero whenever the line is drained for maintenance.
Frequently asked questions
What is an averaging pitot tube flow meter and when do I reach for one?+
An averaging pitot tube flow meter is an insertion DP primary element: a probe carrying multiple sampling ports along its length is pushed across the pipe bore through a single penetration, integrates the velocity profile by averaging across the ports, and produces a differential-pressure signal that any 4-20 mA HART DP transmitter reads. This series is sometimes called annubar after the original Rosemount design, but that name is an Emerson trademark; the generic engineering term is averaging pitot tube. You reach for the averaging pitot on three applications orifice and venturi cannot serve together: very-large-bore service from DN1000 to DN6000 where an orifice would be capex-prohibitive; live-header hot-tap retrofit on cooling-water mains and main steam where shutdown for an orifice installation is not allowed; and head-sensitive circulating service where the orifice 50 to 65 % permanent pressure loss would overwhelm available pump head. Designed per ISO 5167 / GB/T 2624 conventions used in AGA-3 / API 14.3 custody practice.
How does the averaging pitot compare to orifice, venturi, and other DP primaries?+
All four DP primary elements share the same Bernoulli physics and the same ±0.5 % of flow accuracy at this factory, but they differ on permanent pressure loss, install effort, and DN reach. Orifice is the lowest-cost primary, scales DN15 to DN6000, and is the AGA-3 / API 14.3 custody standard for natural gas, but loses 50 to 65 % of the dynamic head as permanent pressure loss. Classical venturi loses only 10 to 15 % and is the choice when permanent head is the binding constraint, but it costs more and tops out around DN1200. Flow nozzle sits in between at 30 to 40 % loss and is used in high-velocity superheated-steam lines. The averaging pitot loses approximately 5 % of dynamic head, is the only primary element that retrofits via hot-tap on a live header, and scales to DN6000 standard with larger sizes by quote. Use orifice for new-build custody, venturi for low-head new-build, nozzle for steam impact velocity, and averaging pitot for retrofit or very-large-bore service.
What is the turndown limit, and why is averaging pitot turndown narrower than vortex or ultrasonic?+
DP physics cap averaging-pitot turndown at 1:3 with a 4-20 mA DP transmitter and 1:7 to 1:10 with HART smart DP. The square-root DP-to-flow relationship means a 10 % flow drop yields 1 % DP, where noise dominates. Pick averaging pitot when you do not need turndown above 1:10 but you do need large-bore service, hot-tap install, low permanent pressure loss, or wide temperature span. If the service requires 1:20 or higher turndown, go to vortex (LUGB), ultrasonic (ULFC), or Coriolis (ZLMFM).
What ships with the averaging pitot, and where is it the wrong choice?+
Lead time is 5 to 7 business days from the factory. The kit ships with the multi-port averaging pitot probe at the specified DN, the welded-hub or flanged process connection per order, the isolation gland and packing for hot-tap or shutdown install, two impulse-line take-off ports with isolation valves, an ISO 9001 wet-flow calibration certificate, and a mill cert traceable to heat number for the wetted-metal grade. The DP transmitter and 3- or 5-valve manifold are separately specified per the previous question. The averaging pitot is the wrong choice on four applications: slurry or particulate-laden flow plugs the sampling ports within hours (go to EMF or Coriolis); pulsating flow downstream of a positive-displacement pump or reciprocating compressor (go to Coriolis); wet steam or two-phase service where the probe sees vapor-liquid mix (go to vortex or Coriolis); and applications requiring turndown above 1:10 (go to vortex, ultrasonic, or Coriolis).
Need an averaging pitot for hot-tap retrofit or large-bore service?
Send pipe DN, operating P + T, fluid, and DP transmitter status (existing stock or factory-supplied). Engineering returns a sized model code, beta-ratio recommendation, and a ship window within one business day; lead time 5–7 business days from the factory.