• Low Cost Design for Industrial OEM and End Users
  • NEMA 4X Enclosure
  • No Moving Parts
  • 316L Stainless Steel Sensor
  • Can Detect Increase or Decrease of Flow
  • Ideal for operation in Liquids, Gases and Slurries

The FD flow switch features the same no moving part priciple of operation as is the lowest cost switch we offer. The low cost is achieved by limiting the process connection to 3/4″ MNPT and power input to 24 VDC. The sensor head is type 316L Stainless Steel and the output is an SPDT relay.

The FD flow switch works using thermal dispersion technology where the temperature of a heated sensor is compared to the temperature of an unheated sensor. This temperature difference is greatest at no flow and decreases as flow rate increases. The unheated sensor acts as a reference such that the instrument only senses flow rate changes and is unaffected by process temperature changes.

This no moving parts design provides great reliability, repeatability and ruggedness to monitor flow rates in virtually all liquids, gases and slurries. In gas applications the instrument is self compensating for changes in pressure since more heat is carried away by more gas particles coming in contact with the sensor probes.

FD Set Point Chart

Flow ranges are shown on the set-point range chart. A conversion chart is also provided in the brochure to convert volumetric flow to velocity.

The electronics feature a SPDT relay rated at 1/2 amp @ 120VAC and 2 amps @ 24VDC and operates with a power input of 24 VDC. The relay energization can be simply changed to be either energized at flow or energized at no flow. Calibration is easily performed by adjusting a potentiometer on the circuit board.

  • Protect Pumps from Low or No Flow
  • Ideal for Air Flow Monitoring
  • Detect Pump or Valve Seal Leakage
  • Moniter Bearing Lubrication Flow
  • HVAC Flow Monitor
  • Indicates or Verifies Flow
  • Chiller Lines - Automatically turns off chiller at no flow to avoid pipe breakage
  • Energy Management - Turns off pumps, heaters, chillers, heat exchanger on loss of flow
  • Safety Shower and Eye Wash Station Flow Switch