Differential Pressure Switch 381 Series Delta Mobrey

Differential Pressure Switch 381 Series Delta Mobrey

Designed in the mid-1970s and developed over subsequent years, the Performance Series switch range offers users the broadest range of options, the highest levels of set-point repeatability, and the confidence of long term performance that a mature product such as this can prove. The model 381 Differential Pressure Switch is suitable for setpoints between -12.5 mbar and 15bar with maximum working pressures up to 110bar.

The Performance Series differential pressure switches utilize a stainless steel diaphragm based sensor. This, when coupled with a precision stainless steel mechanism designed to minimize friction in the moving parts, helps deliver the market-leading performance customers have come to expect from the series.

  • Ranges available up to 15 Bar (200 psi)
  • Weatherproof IP66 enclosures in zinc alloy or stainless steel
  • ATEX and IECEx Ex d Flameproof models available
  • Environmentally and Hermetically sealed switch options
  • Set-point adjustable over the full range against a calibrated scale with the tamperproof adjuster


  • Precision stainless steel mechanism for arduous atmospheres and high humidity.
  • Setpoint adjustable over whole range against calibrated scale with the tamperproof adjuster.
  • Weatherproof and Flameproof models ATEX and IECEx
  • Safety vented or blow out the device as standard.
  • NACE MR-01-75 compatibility.
  • Hermetically sealed microswitch option.
  • Models for fixed switching differential, adjustable differential and HI-LO operation.
  • Ranges available up to 15 bar (200 psi), static pressure up to 250 bar (3500 psi).


The 381 Performance Series is suitable for a wide range of applications in:

  • Oil & Gas
  • Chemical
  • Petrochemical
  • Refining
  • Power
  • Food Industry

The choice of models available ensures that the 381 Performance Series is suitable for use in:

  • Corrosive atmospheres
  • Resistant to chemical attack


  1. Better than 1% set-point repeatability

    Users can expect a set-point repeatability performance better than 1% on all configurations with some configurations being significantly better

  2. Extensive range of options

    The Performance Series switches are available with an extensive range of materials, process connections, switch types, electrical entries, etc, and offer customers many millions of different possible configurations.

  3. More than 35 years of experience in the field

    Installed in a wide range of applications from nuclear power plants to offshore oil rigs, the Performance Series’ long experience in the field offers customers the reassurance that they can be relied upon to survive the test of time in the harshest environments.

  4. Safety

    All Performance Series models come with a safety vent to prevent the enclosure from becoming pressurized in the event that the sensor is inadvertently damaged by excessive pressure

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  • Setpoint repeatability ± 1% of span at 20°C / 68°F ambient.
  • Scale accuracy ± 3% of full scale.

Storage Temperature: -25 to +60°C / -13 to +140°F

Ambient Temperature:

  • -25 to +60°C / -13 to +140°F
  • The special build is also available for temperatures down to -60°C (-76°F) Maximum Process Temperature: Subject to appropriate installation practice, the component parts will withstand up to +60°C (+140°F). For process temperatures up to +120°C (+248°F), order WETTED PARTS Code R (Table 4). For higher temperatures, refer to SPECIAL ENGINEERING.

Enclosure classification: IP66 / NEMA 4X / Flameproof Ex d

Switch output:

  • SPDT or DPDT snap-action microswitch (standard)
  • Hermetically sealed (optional)

Process Connection: Rc 1/4 (BSP), 1/4 NPT Internal, 1/2 NPT Internal & 1/2 NPT External Approximate Weight: Enclosures: “W & N” 4.5kg / 9.9lb; “A & O” 6.4kg / 13.8lb; “H” 5.9kg/13.0lb; “K” 9.7kg/21.4lb; For range C6/CP add 0.4kg/0.9lb; For series 304 add 2.3kg/5.1lb.

Download Data Sheet: Differential Pressure Switch 381 Series

Ref: delta-mobrey.com