The Venturi gas meter used is made according to ISO 5167 standards.
This kind of gas meter gives many advantages compared to other flow measurement systems: the measures stability in the long term, the capability of being used with all weather conditions, a reduced sensitivity to stain thanks to the gas meter self cleaning profile and the absence of elements which are sensitive once in contact with inhaled air.
The flow measure and regulation in relation to actual condition, make ECHO Hi-Vol a unique instrument.
This feature allows the user to change the sample head and flow rate without re-calibrating the flow meter.
ECHO Hi-Vol is equipped with a three stages brushless blower, practically maintenance free, and its averaged life is higher than 20000 hours (more than 2 non-stop operating years).

Two sampling inlets are available, PUF and TSP. These are freely interchangeable.
The PUF sampling module with filter holder of 102 mm and adsorbing cartridge (for PUF or XAD2) of 58 x 125 mm allows simultaneous sampling of
particulate and gas fractions with flow rate between 180 and 220 l/min.
In alternative a filter holder for total particulate (TSP) on membrane of 150 mm diam. is available.
This is required for working up to a 500 l/min flow.