Precise Flow · Calibration · Test Equipment

SNG-30 and SNG-50: galleries with critical nozzles according to DIN EN 9300

Several binary graded, critical nozzles can be connected in parallel and combined in a nozzle gallery. The air or gas flows can be adjusted with the resolution of the smallest nozzle and the approximately double flow of the largest nozzle with a wide range of flow.


A nozzle gallery of the type SNG (Sonic Nozzle Gallery) can generally be equipped with critical nozzles of different throat diameters to use them arbitrarily combined. In most cases, however, a binary approach is followed. The nominal flow of the used n nozzles is oriented to that of the smallest nozzle (Q1) while the nominal flow of the larger nozzles is two or three times (and so on) the amount up to (2n-1) times of Q1.

Product features include:

  • Nozzle gallery for flow calibration
  • Media: air and gases
  • Pressure resistance: -1 bar up to +6 bar
  • Assembly with 4 (up to maximal 8) critical nozzles
  • Inner diameter of the inlet chamber DN 30 or DN 50
  • Throat diameter from 18 μm up to 4 mm or 6 mm

Operating, valve and calibration options

  • Operating mode: suction or pressure operation
  • Medium: air or pure gases
  • Valves: controlled manually or pneumatically
  • Bloc and bleed control: 2 valves on each nozzle section
  • Certificate: factory, DAkkS/DKD or PTB calibration

Short description:

A nozzle gallery allows for calibration of measuring devices for volume or mass flow with a wide measuring range with only one, compact flow adjustment system. The galleries can be automated completely by pneumatically pre-controlled valves. They consist of inlet block, nozzle section with middle block and outlet block. There are 4 connections for sensors (2 x pressure, temperature and relative humidity) and up to 9 connections for nozzle adapters, where the connection on the (other) side of the inlet collecting block takes up the nozzle with max. throat diameter, if required. Each nozzle adapter can be equipped with a critical nozzle.

The used throat diameters should be according to standard Norm DIN EN ISO 9300 and at least 4 to 10 times smaller than the inlet diameter of 30 or 50 mm.

SNG critical nozzle galleries DN 30/50

With more than 2n-1 combinations

More information and technical details can be
found in the data sheet

Additional information
on this subject:


Flow calibration

Flow element software

To our contact page