Model 623

SKU: 623

Flow Switch, Low Flow, Safety Shower and Eye Wash Station Service

The Delta Controls Model 623 Dual Stage Flow Switch actuates at low-flow rates and prevents high pressure drops at 50 times the actuation rate. The switch output is used for alarm or control. The 623 consists of two sections: a flow sensing paddle and a pressure operated flow bypass valve.

As the flow rate increases from zero, the fluid flows through a restriction nozzle and impinges against a paddle, which rotates at the specified rate. The switch is magnetically coupled to the paddle and actuates as the rotation occurs. When the actuation rate is exceeded, the flow bypass valve opens to allow the additional fluid flow to bypass the restriction nozzle. The pressure drop is limited to a low value at highflow rates.


  • Ideal alarm for reactor cooling water loss, eye wash station, or similar
  • Low flow rate alarm in high velocity lines
  • Batch process completion
  • Dual Stage


  • Style: Inline
  • Type: Piston
  • Temperature: ≤ +220 °F (+104 °C)
  • Pressure: ≤ +1200 psig (+83 bar)
  • Actuation: ≥ 0.9 gpm (3.4 L/min) (water)
  • De-actuation: ≥ 0.5 gpm (1.9 L/min) (water)
  • Accuracy: ≤ 10%
  • Output: SPDT or DPDT, 5 A
  • Wetted Material: 300 Stainless Steel
  • Housing Material: 316 Stainless Steel, aluminum
  • Threaded Process Connection: 1 in to 2 in FPT
  • Flanged Process Connection: 1 in to 2 in
  • Flange Rating: ≤ 150 lb

Certifications & Approvals

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

Required Ordering Information

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

Additional Information


Flow Switch, Low Flow, Safety Shower and Eye Wash Station Service

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