Model 626

Flow Switch, Inline Body, Seawater Deluge Service

The Delta Controls Model 626 Paddle Actuated Flow Switch is equipped with a body that becomes an unobstructed part of the pipeline. Model 626 is used to detect very low-flow rates in offshore deluge firewater piping systems. The Model 626 is equipped with a ‘fitted’ full swing-type paddle that fills the inside area of the in-line pipeline body under no flow conditions. It rotates 90 degrees to rest against the inside of the pipeline when the flow rate exceeds the calibrated alarm activation flow rate. The paddle has been ‘cupped’ and ‘fitted’ to fill the pipe and is flush against the pipeline’s interior curve during higher flow rates. Only the paddle’s thin edge, plus its support block, is in the flow resulting in a full pipe size open bore. Therefore during extremely high flow velocities no damage or pressure loss occurs.

For more than 15 years, the 626 has been used to detect seawater flow in deluge fire systems. It is also in service on drill ships and floating production facilities. Model 626 actuates at the very low-low rate which occurs when a single nozzle begins to operate. The paddle is magnetically connected to the output switch. A heavy-duty sealing tube separates seawater from the switch mechanism which eliminates failures occurring due to seal, diaphragm, and bellows leaks.


  • Detects a single nozzle discharging
  • No pressure loss at high flow rates
  • Full open bore, no pipeline restriction
  • Proven reliability for decades
  • Magnetic flow target to switch coupling
  • Flow powered, no other power required
  • Alloy materials suitable for seawater
  • Insensitive to seawater deposits


  • Style: Inline
  • Type: Full swing
  • Temperature: -4 °F to +400 °F (-20 °C to +204 °C)
  • Standard Pressure: ≤ +2000 psig (+137.9 bar)
  • Optional Pressure: +5000 psig (+344.7 bar)
  • Actuation:≥ 3.0 gpm (26.0 L/min) (water)
  • De-actuation: ≥ 3.9 gpm (14.8 L/min) (water)
  • Accuracy:≤ 10%
  • Output: Gold contacts; SPDT, 5 A, 220 °F max
  • Wetted Materials: 316 Stainless Steel, Monel 400, titanium, Alloy 20 (other materials available)
  • Housing Material: Stainless steel, aluminum
  • Flanged Process Connection:2 in to 6 in
  • Flange Rating: ≤ 150 lb
  • Body Gasket:Metal spiral; PTFE seal studs and bolts: A-193BB, A-194; stainless steel

Certifications & Approvals

  • Stainless Steel Housing Options Only: Third Party Listed by CSA NRTL/C (USA and Canada)

Required Ordering Information

  • Detailed model number
  • Complete application number
  • Tag or nameplate detail (if required)
  • Documentation/testing tiers (if required, refer to Additional Resources in the product catalog)

Additional Information


Flow Switch, Inline Body, Seawater Deluge Service

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