Kofloc FM31 Series Small Karman Vortex Flowmeter

General Information

Kofloc FM31 Series Small Karman Vortex Flowmeter employs the following principle for measurement of flows When a columnar object (object that generates vortices) is placed in the flow path of a fluid, regular channels of vortices, called Karman vortex channels, are generated at the back of the object.

Since the frequency of a vortex generated is linearly proportional to the flow velocity within a given range, the flow amount can be measured by counting the number of vortices. When the frequency of each vortex generated is detected by the incorporated vortex detector (piezoelectric device), the signal processing circuit outputs a signal which is linearly proportional to volume flow.

Kofloc FM31 Series Feature

  • Because of no moving part, the meter has superior reliability and durability and no error in mounting position is produced.
  • Simple construction (its flow path of fluid contains a columnar object and a vortex detector only) ensures low-pressure loss and low liquid leak. In addition, the detector does not get into contact with the fluid running through the path, therefore, it is ideal for process monitoring of various liquids.
  • Two types of particle-free body materials (PPS and PFA) are available for choice according to your needs.
  • Global specifications (Certification for CE Marking already acquired)
  • Since Teflon is the material for the entire wetted part and no O-ring is in use, the Model31 Series Karman Vortex Flow Meter is optimum for monitoring liquid flows in the manufacturing process of semiconductors.


    • FA instruments
    • Semiconductor manufacturing
    • LCD
    • Housing material production
    • Medicine production
    • Chemical industry
    • Biomedical applications
    • Environment systems
    • Food processing
    • Agricultural/Botanical applications

Kofloc FM31 Series Specification

Item FM3101 FM3102 FM3103 FM3104
Flow range (L/min) 0.4-4 Feb-20 Mei-50 10-100
Connection 3/8” 1/2” 3/4” 1”
Pipe end Pipe end Pipe end Pipe end
Fluids for measurement Ultrapure water, chemicals, and other liquids
Measuring accuracy ±3.0%+ 1 digit
Repeatability Within ±0.5% F.S.
Liquid temperature range 0-90℃ (No bedewing, no boiling)
Amb. temperature range 0-50℃
Outputs With indicator LED display in 3 digits
Current output: 4-20 mA (linear)
Alarm output: Open collector (2 LEDs; 80 mA, 30 VDC max.)
W/o indicator Current output: 4-20 mA (linear)
Pulse output: Open collector (10 mA, 30 VDC max.)
Supply voltage 12-24VDC
Materials Body All Teflon® (PFA), without O-rings
Cover Polybutylene terephthalate (PBT) resin
Cable 2 meters long; Conductor: Tinned bare annealed copper wire;
Sheath: Heat-/cold-resistant polyvinyl chloride (POC)

Download Datasheet: Kofloc FM31 small vortex flowmeter

Kofloc Product