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Dall Tubes

Dall Tubes

Flow Measurement Excellence

Widely recognized by the Oil, Gas & Petrochemical industries worldwide, Solartron ISA offers more than 45 years experience in the design and
manufacture of primary Differential Pressure flow meter devices.

Dall Tubes have the lowest permanent pressure loss of any primary Differential Pressure flow element. Up to 97% of the DP generated can be recovered.

Dall tubes are suitable for a number of process conditions and are particularly suited for gas transmission pipelines, where significant pressure loss is not tolerated.

The design configuration of the Dall Tube is ideal for clean fluids. It is not suited for fluids with suspended solids.

Solartron ISA offer a range of Dall Tube designs including flanged and insert types to suit various pipe-work configurations, overall length requirements, orientations and end connections. Lines size available range from 50mm up to 1200mm.

We provide complete Engineering support from initial design and sizing concepts to manufactured final products.


  • Proven flow metering technology and robust design
  • Very low permanent pressure loss saving energy
  • Accurate flow metering of clean gases and liquids
  • Negligible wear and erosion with less maintenance/inspection required
  • Shorter overall lengths compared to alternative DP flow elements

  • Specifications +

    • Hydrocarbon, Liquid & Gas Process
    • Gas Transmission
    • Process Measurement

    Key Parameters
    • Proven Technology
    • Robust Design
    • Low Permanent Pressure Loss
    • Accurate Flow Measurement
    • Suitability for Most Process Conditions
    • Minimal Upstream Lengths

    Functional Specifications
    Line Size
    DN50 (1") to DN1200 (48"), Larger lines sizes available on request
    Pressure Ratings Ranging from ANSI 150# to API 15K PSI
    Types of Flow Nozzles Flanged, Butt-Weld, Hub, Insert, Further connections are available on request
    Types of Tappings
    Flanged / NPT / Socket Weld / Thread O’let / Socket O’let, Further types are available on request
    Beta Ratio 0.3 to 0.8 (Dall Tube Type Dependant)
    Reynolds Number ≥ 104

    Accuracy Typically ±3% un-calibrated, ±1% calibrated
    NDT Testing Hydro-testing, Dye Penetrant, Radiography
    Additional options:
    Magnetic Particle, PMI, Gas and Water Calibrations, Further testing is available on request
    Flow Turndown Typically >10:1, depending on Transmitter configuration
    Dall Tube Material Carbon Steel, Low Temperature Carbon Steel, Stainless Steel, Chrome Moly Steel, Duplex, Super Duplex, 6 Mo, Aluminum
    Further materials are available on request

  • Downloads +

  • Guidelines +

    Flowstream Dall Tubes

    ISA Standard Design

    ASME B31.3


    PED 97/23/EC

  • DP Flow Questionnaire +