SELECTIVE GAS PICKUP Russian patent published in 2008 - IPC B81B1/00 

FIELD: measuring technique.

SUBSTANCE: selective gas pickup comprises oscillating member that oscillates at natural frequencies, means for exciting mechanical oscillations of the member, and means of detecting event of transformation of mechanical oscillations of the oscillating member into the resonance mechanical vibrations. The oscillating member is made of conducting nano-fiber whose ends are locked, and the nano-fiber itself is suspended or a number of oscillating member made of a number of conducting nano-fibers are used. The nano-fibers differ in length, diameter, structure and/or type of surface. The means for exciting mechanical vibrations have members for control of tension force of the nano-fibers and at least one control electrode connected with at least one nano-fiber and is capable to affect it by means of the Coulomb force. The means for detecting the event of transformation of mechanical vibrations of individual nano-fiber into resonance mechanical vibrations has devices for measuring modulation of electric current in the circuit of the appropriate nano-fiber caused by the deformation of the nano-fiber itself and modulation of its contact resistances and device for determining the excitation frequency corresponding to the peak of a given modulation of current. The pickup also has means for control of the rate of gas desorption and time of regeneration of the sensing element which has means for flowing current through the individual nano-fibers and/or heater that is external with respect to the nano-fibers, means for calculating relationships between the gas adsorption corresponding to nano-fiber having different properties (length, diameter, structure, surface) and/or under various conditions, means for measuring dynamical and static characteristics of individual nano-fibers, means for detecting of variations of characteristics due to the gas adsorption, and structural members made of selective materials that provide predominant access of the gases of a given type to at least one nano-fiber. The pickup is additionally provided with unit for calculating characteristics of nano-fibers from the shifts of resonance frequencies caused by changes in their temperature due to change of temperature of ambient gas or flowing current through them.

EFFECT: enhanced sensitivity and reduce sizes.

2 cl, 1 dwg, 1 ex