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Noise Control for the Pneumatic Rock Drill.

Authors
Visnapuu-A; Jensen-JW
Source
Ann Mtg SME AIME Chicago Illinois SME Preprint 73-Au-62 Feb 25 - 1973 Mar; :17 pages
Link
NIOSHTIC No.
10010613
Abstract
Unmodified pneumatic rock drills may have noise levels of 115 to 130 db at the operator's position. Experimental modifications have been made to a standard drill to suppress the noise from the three main sources: the air exhaust noise, the noise radiated from the drill, and the resonance noise of the steel drill rods. A prototype model developed at the Bureau of Mines, Rolla Metallurgy Research Center, operates at a noise level below 100 db. A close-fitting case and muffler unit, consisting of a metallic skeleton filled with viscoelastic absorber and having a durable cover, provided both muffling and noise absorption. Damping alloys were used at strategic points in the drill. Drill steel resonance noise was reduced by a constrained-layer treatment on the outside of the drill rod. The singular and combined effects of the treatments are presented in detail.
Publication Date
19730301
Document Type
OP;
Fiscal Year
1973
NTIS Accession No.
NTIS Price
Identifying No.
OP 50-73
NIOSH Division
RORC;
Source Name
Ann. Mtg., SME, AIME, Chicago, Illinois, SME Preprint 73-Au-62, Feb. 25 - Mar. 1, 1973
State
IL;
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