DOG-3 are used for noncontact fl ow measurement of gases.The medium fl ows through an orifi ce in a tube. Bypass bores are located at the sides. The dynamic pressure at the orifi ce causes part of the gas volumetric fl ow to fl ow into the bypass. The division ratio remains constant over the whole measuring range.
The bypass channel contains the Oscillator – the measuring cell itself. When the gas fl ows through the measuring cell, a gas column oscillates in a U-shaped channel mounted to the left and right. This oscillation frequency is proportional to the fl ow velocity and thus to the total volume fl ow. The oscillation frequency is sensed with a hot wire sensor. An electrical alter-nating signal is generated that is displayed in the seriescon-nected electronics.