SELECTIVE FILTERING OF TOBACCO SMOKE BY ENHANCED FILTRATION EFFICIENCY

摘要

SELECTIVE FILTERING OF TOBACCO SMOKE BY ENHANCED FILTRATION EFFICIENCY The specification discloses structure where by applying modulated selectivity constituents are separated from tobacco smoke by stimulated coagulation and adsorption. An ultrasonic generating disc (30) is disposed in the flowstream of the tobacco smoke for generating an ultrasonic field having frequencies up to about 1 MHz to cause coagulation and adsorption of constituents in the flow. The disc (30) includes a ring of semicircular cavities (56), having sharp edges (54) defined on the boundary thereof, which form essentially a ring of vibrojet whistles facing into the flow. The vibrojet whistles are driven by the flow to produce high frequency vortices in the cavities (56). The cavities (56) resonate in phase to create disturbances downstream of the disc 130) which constructively interfere to create a high energy ultrasonic field in the flow. The cavities (56) are arranged so that the energy of the sonic field is directed into a relatively small region thereby inducing coagulation and adsorption.