Lee Kwang-Kil
(Dept. of Safety Engineering Research Occupational Safety & Health Research Institute)
,
Kim Kwang-Jong
(Korea Occupational Safety and Health Agency)
,
Lee Gwan-Hyung
(Korea Occupational Safety and Health Agency)
,
Park Jae-Suk
(Korea Occupational Safety and Health Agency)
,
Son Doo-ik
(Dept. of Safety Engineering, Korea Occupational Safety and Health Atency)
,
Kim Bong-Ki
(Acoustics Group, Korea Institute of Machinery and Materials)
,
Lee Dong-Ju
(Dept. of Mechanical Eng., Chungnam National University)
This paper deals with the noise evaluation technique of a reciprocating air-compressor and its noise reduction. The reciprocating air-compressors are widely used in the small, medium sized industrial firms, and lots of their employees are affected and irritated by their noise in the workplace. Thus,...
This paper deals with the noise evaluation technique of a reciprocating air-compressor and its noise reduction. The reciprocating air-compressors are widely used in the small, medium sized industrial firms, and lots of their employees are affected and irritated by their noise in the workplace. Thus, noise control actions should be taken appropriately by considering the hearing loss due to the occupational noise exposure. Lead-wrapping techniques are employed to identify the contribution of principal noise sources which are generally known as motor, belts, suction/discharge valves, moving pistons, and flow-induced noise caused by edges or discontinuities along the flow path e.g. expansions, contractions, junctions and bends etc .. As a result, main noise sources of the air-compressor can be categorized by the suction/discharge noise, valve noise, and compressed-air tank noise. Based on the investigations, mufflers are designed to reduce both the suction/discharge noise and the compressed-air tank noise. Instead of the conventional valve plate, polyethylene resin is used as a new one for the reduction of valve impact noise. In addition, attempts are made to reduce the valve noise propagation to the cylinder head and the compressor tank by using the insulation casings. As a result of the countermeasure plans, it can be achieved that the noise reduction of the air-compress is up to 10dB.
This paper deals with the noise evaluation technique of a reciprocating air-compressor and its noise reduction. The reciprocating air-compressors are widely used in the small, medium sized industrial firms, and lots of their employees are affected and irritated by their noise in the workplace. Thus, noise control actions should be taken appropriately by considering the hearing loss due to the occupational noise exposure. Lead-wrapping techniques are employed to identify the contribution of principal noise sources which are generally known as motor, belts, suction/discharge valves, moving pistons, and flow-induced noise caused by edges or discontinuities along the flow path e.g. expansions, contractions, junctions and bends etc .. As a result, main noise sources of the air-compressor can be categorized by the suction/discharge noise, valve noise, and compressed-air tank noise. Based on the investigations, mufflers are designed to reduce both the suction/discharge noise and the compressed-air tank noise. Instead of the conventional valve plate, polyethylene resin is used as a new one for the reduction of valve impact noise. In addition, attempts are made to reduce the valve noise propagation to the cylinder head and the compressor tank by using the insulation casings. As a result of the countermeasure plans, it can be achieved that the noise reduction of the air-compress is up to 10dB.
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문제 정의
Here, the goal of the study is to find the contributions of the reciprocating air-compressor noise sources and then to reduce its noise. For these purposes, noise mea surements of a reciprocating air-compressor are carried out to verify the principal noise characteristics.
가설 설정
2. Evaluations of (a) intake noise, (b) motor noise.
제안 방법
2(a), air compressor noise was measured during the operation and compared with the test result of normal operation. At the same time, attaching the microphones to the near-field of suction noise, measurement was carried out to measure the intake noise characteristics. The intake noise has low frequency components between 125-315 Hz corresponding to the harmonic orders of moving piston.
In this paper, the noise contribution analysis of a reciprocating air-compressor was performed. In order to obtain each noise so니rce characteristic, the selective opera tion and lead wrapping techniques are employed during the operations and the contribution of each noise source was obtained.
Selective operation technique was performed for eval uation of motor noise by removing the belts. There was an assumption that no appreciable change in operation and performance of the motor would occur due to the disconnection.
참고문헌 (4)
ISO 1680/1-1986, 'Acoustics-test code for the mea-surement of airbome noise emitted by rotating electri-cal machinery - Part 1: Engineering method for free-field conditions over a reflecting plane.'
Leo L. Beranek, Noise and Vibration Control, McGraw-Hill, 1971
MIL-STD-740-1(SH)-1986, 'Airbome sound measure-ments and acceptance criteria of shipboard equipment
M. L. Munjal, Acoustics of Ducts and Muffters, John Wiley & Sons, Inc., 1987
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