Case studies
Sound damping of vibrating shake-out line in the foundry
In the foundry of grey cast iron a line for production of castings was put into operation. In the final stage of the technological process the castings must be removed from moulds – and it is a very noisy procedure. The management of the firm decided, in the framework of ecological program, to improve living and working environment of employees by reducing the noisiness of the line.
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Result:
Reduction of noise level L(A) radiated by the line by 7 dB
Summary:
The whole project was a “long-distance race”, the resulting effect of our supplementary noise-damping measures, however, was at least partially achieved – the noise level in the place of operators of the line was reduced. The working environment of employees is better and their hearing is not attacked by such high noise levels as in the beginning. Further improvement of noise parameters of the working environment in this foundry will be achieved by reduction of noise of surrounding technological equipment in the production shop.
(taken from Center of environmental hygiene of State Health Institute Prague)
Noise is every unwanted sound that is disturbing or troublesome or that affects adversely human health. Negative effects of noise on human health are partly specific ones, presented by disorders of the function of acoustic analyzer, partly non-specific ones (extra hearing), when functions of various systems of the organism are affected. These non-specific system effects appear almost in the whole range of noise intensities, frequently they are accompanied by stress reaction and impact on neurohumoral a neurovegetative regulation, biochemical reactions, sleep, higher nervous functions, such as learning and memory, impact on sensory motoric functions and coordination.
…(more…)Authors:
RNDr. B. Madejewski,CSc., Ing. V. Kotrba, CSc.
The article describes the design, calculation and test results noise attenuation of the noise hood for large industrial compressors driven by electric motors. Predicted noise attenuation (software UTLUM) has been validated by practical measurements at the customer¢s place.
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