The Sigma 400 series

Sigma 400 flow / consumption sensor (insertion type)



The Sigma 400 series flow sensor  is based on the thermal mass flow principle. It measures volumetric standard flow over a wide measuring range. The result is pressure and temperature independent.

The sensor installation into the pipe is done through a ½” ball valve. This makes it possible to do the installation under pressure without shutting down the compressed air line.The sensor is available in two measuring ranges and with or without display. The version with display shows the actual volumetric flow and the total consumption. Via the keyboard tube diameters and the consumption counter can be set.

Every sensor includes an analogue output (4…20mA) for flow and an isolated pulse output for the consumption counter.

Special Features

  • Integrated display for m3/h and m3
  • Depth scale for accurate installation
  • Usable from 1/2” to 12” (DN 300)
  • Easy installation under pressure
  • 4...20 mA analogue output for m3/h resp. m3/min
  • Pulse output for m3
  • Inner diameter adjustable via keypad
  • Consumption counter resetable
  • Insertion type sensor for installations under pressure
  • Thermal mass flow, independent of pressure and temperature changes


Technical data

S400  Measured unit  m3/h, m3/min, l/min, cfm  

Accuracy  +- (3% of measured value + 0.3% full scale)  

Medium  Air, gas, non explosive  

Operating temperature   -30 ... 140 ºC probe tube                                  

 -30 ... 70 ºC casing  

Operating pressure  Up to 50 bar  

Analogue output : 4 ... 20 mA Scaling:   0 ... max range  

Pulse output  1 pulse per m3  

Power supply  12 ... 30 VDC, 100 mA

Volumetric Flow ranges

Inch mm Standard [m3/h] Max [m3/h]
1" 27.3  
0.5...150  0.6....320 
2" 53.1 
3" 84.9  5...1600 7....3400
4" 100.3 9...2700 12....5700
5" 133.7 13...4000 18....8400 
6" 162.3 18...5800 25...12000
200.0 26...8800 33...18000
250.0 40...13700 52...29000
300.0 60...19800  80...40000
The stated flow rates are standard flows at 20 ºC and 1000 mbar  

Applications (*)


  • compressed air
  • nitrogen
  • argon
  • helium
  • CO2

(*) state type of gas on order



Precise installation and removal under pressure


Alignment aid

Precise installation with alignment aid

included in set



Sigma 430 is an insertion type flow meter using the pitot tube principle, designed for flow and consumption measurement in wet air, high mass flow or high velocity applications. Installation requires a G3/4″ connection and the mounting stem is graduated to simplify centering the sensor tip for pipe sizes up to 12″ diameter (DN300). Contact us for larger diameters

Sigma 430 has a new 3 line colour display displaying flow, velocity and pressure with bluetooth interface for remote sensor configuration. Sigma 430 offers a choice of communication options including 4-20mA, pulse and SDI (our Digital Interface), Modbus/RTU and MBUS.

Pressure range up to 1.6MPa
Output 4-20mA, SDI, Modbus/RTU, MBUS
Optional colour display
Bluetooth interface

Sigma 430 is ideal for measuring at the compressor outlet as the pitot tube design is not damaged by the very wet gas unlike thermal mass flow sensors which cannot be used here. Sigma 430 offers FAD calculation facilities for accurate measurement of compressor performance.