Mass Flow Measurement Grid

  • Volume measurement of gaseous media in ducts, especially for comdustion air for firing applications
  • With a minimum of differential pressure loss, compared to the conventional technology
  • Short length of inlet- and outlet-stretch for laminar flow. Long air-ducts are not required anymore
  • Stainless steel material
  • Basic temperature range up to 400 °C
  • Free of maintenance for use in clean air application
  • Rectangular and circular grid versions are available
  • With increased dust particles loading, flushing back can be done (option)
  • Connection to the Differential Pressure Transmitter by impulse piping or on customer‘s request
Technical Data

The grids are made by specifications of the customers. Therefore the technical data can be indicated only generally. In the case of concrete offers, and/or supplies a data sheet made particularly for the appropriate grid is provided.

MaterialStainless steel 1.4404
(other materials on request)
Pneumatic connection

Sleeve G1/4″

Installation types 
  • Flange connection
  • Welding execution
  • Clamping connection for „Jacobrohr“
Applicable temperature range+5°C…+400°C
(other temperature ranges on request)
Measuring mediaAll not aggressive, not explosive, gaseous media with well-known density
System pressure-0,5…+0,5 bar (negative/positive pressure)
Repetition accuracyGenerally repetition accuracy ≤ +/- 1% from measured value
Measuring accuracy 
  • Calibrated grids on the test assembly ≤ +/- 1% from measured value
  • Calculated grids +/- 5% from measured value
  • Calibrated grids local ≤ +/- 2% from measured value

The principle is based to the Bernoulli theory, which means, that the total kinetically energy of the flow-stream neglecting the friction, – stays the same, namely the sum of the dynamic and static pressure. The Stagnation Pressure Grid overs partially the area of the duct, so that it increases the flow-speed in reference and relation of the static pressure. This pressure is measured on special positioned openings. The on this way measured pressure difference is 2- to 3 – times higher, then the middle dynamically pressure in the duct flow-stream, for which the flow-speed has to be within of 3 and 40 m/sec.

The parallel adjusted pipes (with closed ends) build up an open grid across the duct area rectangular to the stream axis. Some of these pipes have openings to read the total pressure, other pipes are taking the reference pressure. These two pressures are feed into separate summing-pipes and also to separate connecting stubs. The pressure difference of these two values define the transmitter output signal.

Selection Criteria

standard type dimensions
grid circular:

Standard type dimensions
grid rectangular:

Selectable diameter from 100 mm to 1600Width x height in mm vonn 200 x 200 to 1100 x 1100
Duct stretch L = 100mmDiff. Pressure connection, on hight-sideconnection, piping stubs 12 mm
Material thickness 3mmSteel sheet stiffener and counter fixing for width side dimensions > 600 mm
Optional: With flange and counter flange