| 摘要 |
1,206,307. Silencing gaseous flow. RHONEPOULENC S.A. Nov. 20, 1968 [Nov. 21, 1967], No.55151/68. Heading F1B. Apparatus for smoothing pressure variations in gaseous flow comprises a tubular wall having an inlet and an outlet, at least a portion of the wall being elastically deformable under the influence of variations in dynamic pressure, substantially proportional to such variations, and axially spaced apart baffles extending inwardly from the deformable portion of the wall and each leaving a free passage for flow having an area equal to at least half of the cross-sectional area of the deformable portion at the location of such baffle. The I. C. engine silencer shown comprises an elasticity deformable wall 2 in the form of a conical bellows of increasing diameter in the direction of flow and having annular or helical corrugations. Helically wound springy steel wires may be embedded in helical corrugations. The wall 2 carries baffles 6, 7, 8 which may be annular with the internal diameter of successive baffles decreasing in the direction of flow but preferably are semi-circular and staggered as shown. Each baffle closes off not more than half the flow area. The baffles may be prolongations of the edges of certain corrugations or may coincide with the edges of these corrugations. The wall 2 is followed by a cylindrical part 3 and a profiled part 4, which parts may be lined with silicone foam or roughened to maintain an appropriate boundary layer or vibration damping zone. At least the wall 2 but preferably the entire assembly is made of a silicone elastomer, reinforced where necessary. Metals and natural and synthetic rubbers (which may be cloth-covered or reinforced) and fluorinated elastomers may be used. The part 3 may be a metal sleeve. In a pulsation damper for the discharge from a compressor, a cylindrical bellows may be used. To enable the bellows to withstand the internal pressure, the damper may be enclosed in a metal tube in which is set up a pressure of the same order of magnitude as that within the damper. |
