Modern flowmeters have thermoanemometer tester of air flow. It
works as: heat exchanger element from a thin platinum wire
(diameter about 0.07 mm) disposed in the flow of air The
increase of air flow leads to an increase in the electric power
for maintaining of the desired temperature difference between
the wire and wrapping it air.
amount of heat, carried away by the gas flow, depends on the
physical characteristics of a moving fluid, on the geometry and
orientation of the wire. It is known, that increasing of the
wire temperature and growing of the area of contact between the
gas and the heating elements, increases the sensitivity of
most modern meters are the film thermoanemometers. They have
heating and measuring resistors produced as a thin platinum
layers, deposited on the surface of a silicon crystal.
Using thin-film chips, created by the TAF-technology, can
further improve their sensitivity. An important feature of
offered products is not required to reduce the cross-section of
gas pipeline, when low rates flows are measured.