• ¼” Tubing Connection
  • 316L Stainless Steel Sensor
  • No Moving Parts
  • Temperatures to +250F
  • Low Flow Rate Detection
  • Simple and Easy Field Calibration
  • Field Programmable for Relay Energization
  • Reliable and Cost Effective
  • Pressures to 2000 PSIG

The IM series in-line flow switch is designed to easily adapt to ¼” tubing. Please refer to the IX or FX series for larger line sizes. These switches have no moving parts exposed to the product being monitored and offer an extremely reliable and repeatable instrument for sensitive process controls. The device operates by measuring the temperature differential between a heated and a reference temperature sensor. The differential is greatest at no flow and decreases as flow is achieved across the sensor. This allows use in applications requiring a simple flow/no flow detection and for set-points at a predetermined flow rate. Different flow ranges are shown in the set-point range section for water, hydrocarbons, and air/gas.


Extremely low flow rates can be detected with a typical turn down ratio of 300:1. The no moving parts principle of operation allows this flow switch to be used in practically all liquids, gases and slurries.

The electronics are available with single or dual switch points, or an additional temperature switch may be added. The instrument can be easily field programmed to detect an increase or decrease of flow. Relay outputs are standard and are offered with several different configurations and contact ratings (3 and 10 amp).


  • Pump Verification: Verifies pump operation, able to detect flow rates down to .09cc/second in water
  • Bearing Lubrication: Detects loss of flow down to .06 cc/second in hydrocarbons
  • Seal Leakage: Verifies positive seal flow or detects excessive leakage indicating maintenance requirement
  • Chemical Feed, Dosing, and Metering Pumps: Indicates low or no flow of chemical additives to process
  • Spray Nozzles: Able to detect nozzle blockage in coating applications
  • Relief Valve/Rupture Disks: Alarms on burst or leakage of safety relief valves or rupture disks
  • Chiller Lines: Provides automatic shut down of chillers on low or no flow to prevent costly repairs
  • Analyzer/ Gas Chromatographs: Confirms continuous and/or sample flow to instruments