The noise deteriorating effect on the efficiency of labour and human health is commonly known. In the past decades the noise quieting problem in developed nations of the world, and our country as well, has become a top-ranking one.
The noise effect on the worker´s body goes beyond the influence on the organ of hearing only. Hygienists have found out that in some noisy branches the general morbidity rate rises by (10...15)%. It is proved that even the levels of (40...70) dBA have an effect on the vegetative nervous system irrespective of the subjective noise perception of the person. The habituation of the person to noise is illusive, as noise affects even the sleeping person.
The action of noise is often coupled with the effect of other destructive for human health factors: vibrations, irradiations, dust and gas content, etc. It also accentuates the requirements to restrict noise exposure and promotes the untimely retirement benefits.
It must be emphasized that the USSR was the first in the world to initiate the noise attack by law (The Resolution of the Council of Ministers of the USSR 1960, 1969, 1973).
In 1971 the "Sanitary standards of industrial institutions" CH 245 - 71 and "Hygienic standards of sound pressure and volume tolerance levels at work places" ГН 1004 - 73 were developed. The Committee of Measures and Active Measuring Instruments at the Council of Ministers of the USSR established a series of Noise National Standards included into the "System of Labour Safety Standards". Nowadays the sanitary norms СН 2.2.4/2.1.8.562 - 96 work, where the noise norm for working places makes 80 dBA on the sound level.
The requirement toughening for noise from 90 dBA (according to СН 245 - 71) up to 80 dBA forced us to work in 3 directions in this problem solution [1 - 6].
1. The investigation of noise, causes and noise making objective laws of active processing equipment as part of processing lines and departments. The saw and woodworking equipment is, as is known, characterized by a high efficiency, at which one has to appoint process speeds from 40 to 100 (and even faster) m/sec with feed velocities up to 150 m/min.
Let us note that the quantity of working tools (saws, shaft arbors) to provide the efficiency achieves the number of 4-10 and more in one machine. For the moment of our works starting (meeting of 60-70s of the past century) there was no slightest hint in the operating equipment and technological designs to any noise reducing solutions in the constructions, working areas, plant and seliteb (by-plant) territories. On the active processing equipment, at the minimal interference with the construction, we developed the devices with due consideration of rather various methods of noise control: the acoustic suppression in the generation places, sound protection and absorption, acoustic shielding and noise localization methods. A noticeable (5...10 dBA) effect was obtained. In some instances we managed to interfere with the mainstream technology as well, when the equipment location was determined by the technology requirements only. The shop drawings of the devices were sent by us in a great amount at the request of numerous enterprises (not only saw and woodworking industries).
The dominant requirement, which would exclude the rejection of antinoise devices by the workers, was sustained by us in the direction of technological capabilities non-reduction of a machine or aggregate.
2. The results of theoretic and experimental research have served the foundation for the leading engineering materials complex development for production workers, design engineers, original equipment (methods, guidance, instructions, drawing albums) manufacturers. All of them have come through the stages of reconciliation with the State design institutes of the branch, production engineering design consultancies, main engineering department on woodworking processing equipment design, Research and development institutes of the branch and original equipment manufacturers, trade union Central Committee of the branch before the approval of the Ministry of Forest Industry. So that the design engineers "were not afraid" of acoustic designs (and it would be a novelty for them), we carried out a week training. The following years of communication with engineering designers testified that necessary theoretical knowledge on noise, methods of design policy for all possible technological situations, types of shop floors and equipment stock, illustrated with plenty of numerical examples, allow them to lead acoustic designs without any difficulties.
With the appearance of data-flow computers we created the computation algorithms and programs included into 2 instructions on computer-aided acoustic design systems application.
3. The work with the Machine-tool Industry Ministry, its plants and development laboratories promoted the operating equipment modernization positive results shift to the series-produced one.
Let us note that many technological solutions were performed by us taking into account the world´s patent novelty. It, naturally, promoted a more active advance of research ideas into production.
References:
- Cheremnykh N.N. Noise reducing devices for woodworking equipment / Cheremnykh N.N., Chizhevsky M.P. // Design Atlas. Issue 1, - M.: Ministry of Forest Industry of USSR, 1974 - p. 70, Issue 2, 1978 - p. 15.
- Chizhevsky M.P. Conducting materials on noisiness calculation and anitinoise measures planning at saw and woodworking industries [text]/ Chizhevsky M.P., Cheremnykh N.N.// - M.: Ministry of Forest Industry of USSR, 1978 - p. 367.
- Cheremnykh N.N. Methods of noise reducing devices construction for radial saw machines of longitudinal and cross sawing with all kinds of actuating elements thrust [text] - M.: Ministry of Forest and Paper Industry of USSR, 1982 - p. 97.
- Cheremnykh N.N. Scientific basis of noise reducing devices of saw and woodworking industries equipement [text] // Collection of materials of international scientific- technical conference "Social-economical and ecological problems of forest complex" - Ekaterinburg: USFEU, 2003 - pp. 168-170.
- Sannikov A.A. Vibration and noise of production machines and equipment of forest complex branches [text] / Sannikov A.A., Starzhinsky V.N., Kutsubina N.V., Cheremnykh N.N., Sivakov V.P., Vikharev S.N. - Ekaterinburg: USFEU, 2006 - p. 484.
- Cheremnykh N.N. Nonregistered accountable factors at reduced noise formation production machines set-up [text] // Cheremnykh N.N., Shestakov A.N. / Woodworking industry, 2007, №4, с. 18-19.
The work was submitted to international scientific conference «Engineering sciences and present-day production», China (November, 26 - December, 4, 2007, came to the editorial office 03.12.2007.