GB504795A - Improvements in or relating to means for absorbing noise produced in rooms or chambers containing noisy machinery - Google Patents

Abstract

504,795. Nonconducting coverings for sound; compound fabrics; silencing gaseous currents. FRANCOIS CEMENTATION CO., Ltd., NEELANDS, A. R., and KLOPSTOCK, K. Oct. 29, 1937, No. 29614. [Class 64 (ii)] [Also in Groups XXVII and VIII] A room or chamber housing noisy machinery having a ventilating air inlet and outlet is provided on its walls, ceiling and at its ventilation ports with sound-damping material to absorb medium and low frequency vibrations, the material on the ceiling and at the ventilation ports being combined with other material to absorb high - frequency vibrations. The walls 13 of the room are covered on both sides with a layer of glass wool 16, 17, and the spaces between buttresses 19 are wholly or partly filled with slag wool 22, the fibrous material being covered on the inside of the room with metal panels 24 affixed to battens 18, 20, 21. The slag wool layer 63, Fig. 8, spaced from the underside of the ceiling is combined with a layer of copper tangle 65 covered with expanded metal, layers of aluminium foil 62 and fireproof calico 64 being also arranged on either side of the slag wool if desired. A three-stage silencing arrangement is provided at the inlet and outlet ventilation ports, the sound waves first passing through a honeycomb built up of walls of mineral wool covered with metal sheets, the walls tapering to sharp edges at the entrance side of the honeycomb. The sound waves then pass through the vertical spaces between parallel curtains suspended on stanchions 42, Fig. 7, arranged in a wavy formation in the direction of movement of the waves. The curtains comprise horizontal sections carried by cross frames 43 between and attached to the stanchions; the sections consisting of woven or tangled copper wire 44, with a core of mineral wool 45 with optionally an interposed layer of asbestos cloth 48. At the bends of the wavy formation, the copper tangle is covered with steel plates, the remaining parts being enclosed by expanded metal or wire mesh 47. The sound waves finally pass through the horizontal spaces 50, Fig. 2, between sinuous mattresses composed of slag wool 53, covered on each side with fireproofed calico and then with wire netting 55, the mattresses resting on supports 52.