RESEARCH OF THE EXHALATION VALVE EFFECTIVENESS IN THE FILTERING HALF MASKS

Details

Parent Category: Geo-Technical Mechanics, 2014

Category: Geo-Technical Mechanics, 2014, Issue 115

UDC 614.894.28.001.5

Authors:

T.I. Dolgova, D.Sc. (Tech.), Professor,

S.I. Cheberyachko, Ph.D. (Tech.), Associate Professor

D.I. Radchuk, Ph.D. (Tech.), Associate Professor 

(SHEE «NMU»)

Abstract.

Purpose.To investigate efficiency of different exhalation valve constructions in a cyclical air stream. Methodology. Tests on determining exhalation valve leaktightness in accordance with the requirements of DSTU EN 149:2003 and GOST 17263-79; rubber elasticity was estimated in accordance with GOST 27110-86. Findings. It is stated that the leaktightness depends on the rubber thickness and elasticity and fastening of the exhalation valves. With a rubber certain elasticity, an optimum thickness of the exhalation valve petal should be observed in order to ensure maximum leaktightness. Foreign objects in or damages of the valve saddle may worsen the leaktightness, but the increased vacuum pressure of the valve of the mushroom form reduces leakage from the gap between the mask and  face. It is also stated that the maximal quantity of aerosol comes into the gap between the mask and  face during the closing of the exhalation valve in the early inhalation phase. All tested exhalation valves comply by their leaktightness with the standards. However, the best result was recorded with the valve of mushroom form and the worst – with the petal valve. Novelty. At contact of the saddle with the foreign objects, or in case of some damages caused by increased vacuum pressure, leaktightness of the exhalation valve of the mushroom form is improved thanks to the rubber elasticity as the rubber can tightly cover the objects which could get onto the saddle and, thereby, reduce size of the gap; at the same time, this characteristic worsens in the valves of the mushroom form. Practical value.It is stated that optimum value of the exhalation valve thickness is 0.4 mm with elasticity of the rubber within 50-60%.

Keywords:

exhalation valve, leaktightness , pressure drop, leakage, pressure drop, leakage.

References:

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About the authors:

Dolgova Tetiana Ivanivna, Doctor of Technical Science (D.Sc.), Professor of Ecology department, State Institution of Higher Education «National Mining University», Dnipropetrovs’k, Ukraine.

Cheberyachko Sergey Ivanovich, Candidate of Technical Science (Ph.D), Associate Professor of department Aerology and protection of labour, State Institution of Higher Education «National Mining University», Dnipropetrovs’k, Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it. .

Radchuk Dmytro Іgorovych, Candidate of Technical Science (Ph.D.), Associate Professor of department Aerology and protection of labour, State Institution of Higher Education «National Mining University», Dnipropetrovs’k, Ukraine, md2185@mail.ru

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