Model 626

Flow Switch, Inline Body, Seawater Deluge Service

The Delta Controls Model 626 Target Actuated Flow Switch is equipped with a body that fits into, and becomes part of the pipeline. It 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 target that fills the inside area of the inline pipeline body under no flow conditions. It rotates back 90 degrees to rest against the inside of the pipeline when the flow rate exceeds the calibrated alarm activation flow rate. The target has been ‘cupped’ and ‘fitted’ so that it fills the inside pipe area and is flush against the interior curve of the pipeline during higher flow rates. Only the thin edge of the target, plus its support block is in the flow. The inside area of the pipeline is not restricted and the result is a full pipe size open bore. This design allows extremely high flow velocities without damage or pressure losses.

The 626 has been used to detect seawater flow in deluge fire systems for more than 15 years. It has been used on offshore oil platforms in the North Sea, the Gulf of Mexico, the Persian Gulf, as well as near Australia, Indonesia, and Russia. It is also in service on drill ships and floating production facilities. The 626 can actuate at the very low-low rate which occurs when a single nozzle has begun to operate. Connection of the target to the output switch is done magnetically. A heavy-duty solid sealing tube separates the seawater from the switch mechanism. Failures which can occur due to seal, diaphragm, and bellows leaks are eliminated.


  • 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)
  • Pressure:
  • Standard: ≤ +2000 psig (+68.9 bar +137.9 bar)
  • Optional:+5000 psig (+344.7 bar)
  • Actuation:≥ 3.0 gpm (26.0 L/min) (water)
  • Deactuation: ≥ 3.9 gpm (14.8 L/min) (water)
  • Accuracy:≤ 10%
  • Output: Gold contacts; SPDT, 5 A, 220 °F max
  • Available Wetted Materials: 316 Stainless Steel, Monel, titanium, Alloy 20 Other materials available
  • Housing: Stainless steel, aluminum
  • Flanged:2 in to 6 in
  • 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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