How to deal with difficult flow applications

Transit time flow meters are an innovative technology and available in a variety of different formats including wall mount and DIN rail mount.


  • Works with all liquids that conduct sound – with no aeration and solids <20000ppm                                  
  • Bi-directional +/- 16m/sec with totalisation
  • Install and maintain without dismantling pipe systems
  • Pipe sizes from 15mm to 6000mm
  • Suits many pipe materials: SS, steel, copper, plastic, cement and in many cases with linings
  • High pressure, aggressive liquids, sterile/hygienic applications
  • Temperatures to 160C with high temperature sensors
  • High accuracy of +/- 1%; repeatability 0.2%  when applied correctly

These flow meters are available in different formats including wall mount, DIN rail mount and portable with power supplies from 12-36VDC as well as AC and including battery and solar powered installations. Download the datasheet for more information.

How does it work?

Transit time flow meters measure the time a soundwave takes to travel between two sensors (with the flow and against the flow) and the difference is used to calculate the average fluid velocity and flow. Sensors may be strapped on to existing pipework, inserted in existing pipework, or fabricated into pipe sections in the same way as many other styles of meter – for example between flanges.

The sensors interface with intelligent electronics in different formats – DIN rails mount, wall mount or portable, and these devices are set up reflecting the exact geometry, the fluid type, the pipe wall thickness and material.  Flow will then be calculated and outputs generated as programmed.

What applications does it suit?

The technology works in most situations. There are variations in sensor arrangement, and sensors for direct contact with the fluid for increased sensitivity. Set-up menus give choice of materials and geometry

For temporary tests, longer term data logging, and testing before installation of a fixed system, portable TTFM kits are available – such as TDS100H (shown above).