MULTISECTION SILENCER Russian patent published in 1996 - IPC

FIELD: mechanical engineering. SUBSTANCE: multisection silencer has cylindrical housing rigidly connected with inlet branch pipe which is rigidly coupled with central perforated pipe. Placed coaxially between housing and central pipe is at least one additional perforated pipe. End faces of all pipes are rigidly connected with housing by means of blind partition located at side opposite to inlet branch pipe. Other partition coupling pipe end faces is either extension of inlet branch pipe flange (as shown in drawing) or can be rigidly secured on branch pipe flange by any known method (not shown in drawing). Pipe perforation holes in peripheral parts, are made alternating in arrangement. Multisection silencer operates as follows. Sound waves, together with turbulent flow of compressed air, get into space of central perforated pipe, blind partition playing part of sound isolating screen. Resonance spaces formed by coaxially arranged pipes operate as Helmholtz resonators, holes serving as necks of resonators arranged in tandem. Helmholtz resonators can be tuned to any frequency band by selecting clearances between pipes and diameters of holes and required efficiency of noise suppression can be provided by selected number of resonators. Use of several pipes in offered silencer enhances noise suppressing capacity at direct penetration of sound waves. Resistance of silencer is relatively low owing to use of non-through holes which increases their pass-through capacity. EFFECT: enhanced quality of noise suppression. 2 cl, 1 dwg