• Fast Response for Time Critical Applications
  • No Moving Parts
  • NEMA 4X Explosion Proof Enclosures
  • Threaded, Flanged, or Retractable Probes
  • Low Flow Rate Detection
  • 316L Stainless Steel Sensor/Nickel Braze
  • Temperatures to +350F
  • Field Calibration is Simple and Easy
  • Pressures to 2000 PSIG

The QX series flow switch offers the same reliability as our FX series and also offers a faster response time. These fast response flow switches are used when the response time in detecting the increase or decrease of flow is critical. With no moving parts exposed to the process they will provide extremely reliable and repeatable operation in virtually all liquids, gases, and slurries.

The sensor head employs two temperature sensors with a constant very low power heating source physically attached to one of the temperature sensors. The second temperature sensor is isolated from the heating source and provides compensation for changing process temperatures. As the rate of flow changes so does the temperature differential. This allows the device to be used as a flow/no flow sensor, or to switch at any velocity shown in the flow switch range chart. The dual set point option provides two separately adjustable switch points.


Extremely low flow rates can be detected with rangeability up to 300:1. This instrument is ideal for use in virtually all liquids, gases, and slurries. No moving parts exposed to the process provide end users with an extremely reliable and repeatable flow switch even in viscous or corrosive applications.

The electronics are available with single or dual switch points. A SPDT 3 amp Relay output is standard and are offered with several different configurations and contact ratings. Temperature monitoring is also available with either a switch output or a linear 4-20 mA output.

Remote mounting of the electronics is also available for hard to reach or high temperature applications.

  • Pump Protection: Automatic shut down on low or no flow
  • Bearing Lubrication: Can quickly and reliably detect loss of flow even with very low flow rates
  • Seal Leakage: Verifies positive seal flow or detects excessive leakage indicating maintenance requirement
  • Chemical Feed and Metering Pumps: Indicates low or no flow of chemical additives to process
  • Safety Shower/Eye Wash Station: Automatic annunciation of potential danger to plant personnel
  • Analyzer/ Gas Chromatographs: Confirms continuous sample flow to instruments
  • Control Rooms: Automates verification of flow when fans, pumps or valves are energized
  • Purge Air: Fast response on loss of flow for process or plant safety
  • Spray Nozzles: Detects nozzle blockage in coating applications
  • Relief Valve/Rupture Disks: Quickly alarms on flow or leakage of safety relief valves or rupture disks
  • Chiller Lines: Automatic shut down of chillers on low or no flow
  • Heater Burnout Prevention: Heater shutdown on loss of flow to prevent overheating of elements
  • Tank Car Loading: Quickly senses dry line or phase change from liquid to nitrogen gas flow
  • Drain Line Sensor: Capable of detecting flow in partially filled lines
  • Agitation Monitor: Positive indication of agitation in tanks