Multi nozzle is used for specialized test facilities in which the scope of the measured flow is set by number of open (unblinded) nozzles. In 1997 issued ISO 5801 standard is specifying geometry, way of utilization incl. assembly and operation conditions for meters used as test measuring devices for mass production of HVAC equipment.

Design of the multi nozzle is, that several nozzles (even of different diameters) are mounted on a common plate.

These flow meters have advantage of covering wide range of measurement by one measuring chamber. Based on the long-term monitoring of special Venturi tubes and multi nozzles in operation it was found out that in terms of quality of measurement, assembly, maintenance and operation these are very suitable for specialized industrial test facilities – for calibration of compressors and flow equipment as well as test meters for mass production of HVAC equipment.

Individual bodies of multi nozzles are usually made of stainless steel or aluminium alloy, or even of hardened plastic. Retaining plate of the multi nozzle is usually made of carbon steel or hardened plastic.