Leader of work: assistent Vovna Alexander

Abstract

Introduction

Urgency

Communication of work with scientific programs, plans, themes

The work purpose

Work problems

Scientific novelty

The basic material of work

Conclusions

Literature

Introduction

On collieries of Ukraine annually there are tens flashes and methane explosions. Consequences of the big explosions is both considerable number of human victims, and a huge loss of property. The biggest accidents in a world history of mining have been caused by explosions of methane and a coal dust. In this connection introduction of actions for prevention of explosions of miner atmosphere has indisputable social and economic benefit.

Principal cause of explosions is high concentration of methane which is supervised by means of special devices. Methods which exist today, and gauges of concentration of methane do not provide necessary speed of devices of measurement of concentration of methane in atmosphere of coal mines.

Urgency

With increase in depth of workings out of coal increases газоносность developments, intensity and frequency газодинамических displays that is in turn interfaced to danger increase at conducting mountain works increases. Hence necessity for re-equipment of collieries by continuously operating means of the automatic control of concentration increases in such conditions gas a component of the raised speed. Methods and means which exist today, do not provide necessary speed and demanded accuracy of devices of measurement of concentration of methane in atmosphere of coal mines. The measuring instrument should be quick-response with a wide dynamic range and tolerant to influence of the basic revolting factors of miner atmosphere of coal mines. Thus detailed studying and working out of ways of increase of speed is necessary at demanded accuracy of the control of concentration of methane with indemnification of influence of the basic destabilising factors of miner atmosphere of coal mines.

Communication of work with scientific programs, plans, themes

 Master's work is executed within the limits of state budgetary research themes of the State higher educational institution «Donetsk national technical university» D-14-07 «Development of fast-acting measuring instrument of concentration of methane for system of gas protection of coal mines»

The work purpose

The purpose of works: increase of speed of measurement of methane in coal mines with use of the system approach, by application optical absorption a quality monitoring of concentration of methane from indemnification of dynamic indignations of the environment influencing results of measurements.

Work problems

 For realisation of idea and purpose achievement магистерской works are put following problems:

· to analyse methods of measurement of concentration of methane in the conditions of coal mines and a way of improvement of their metrological characteristics, to reveal the factors influencing indicators of accuracy optical absorption of method, and to develop principles of their indemnification;

· to develop mathematical model of the channel of measuring instrument of concentration of methane on a basis optical absorption method with use of the optical channel and the method of indemnification eliminating dynamic indignations of environment, measurements influencing results;

· to prove the structurally-algorithmic methods providing demanded accuracy of measurements, high speed of the device of measurement of concentration of methane in the conditions of collieries.

The decision of the given problems - a basis for working out of the block diagramme of the high-speed device of measurement of concentration of methane for system of gas protection of collieries.

Planned result - the block diagramme of the developed device constructed on the basis of developed mathematical model

Scientific novelty

During work new results will be developed and received:

·  further development optical absorption  quality monitoring of concentration of methane in coal mines, on the basis of use of the open optical measuring channel that has allowed to raise speed of measuring instruments of concentration of methane at demanded accuracy of the control is had.

·  structurally-algorithmic methods providing demanded accuracy of measurements, high speed of the device of measurement of concentration of methane in the conditions of coal mines are developed

  The basic material of work

The analysis of existing methods of measurement of concentration of methane

Having analyzed merits and demerits of existing methods of measurement of concentration of methane, has been chosen optical absorption  measurement method. The optical absorption  method of the gas analysis is based on the selective absorption of radiant energy defined by components of analyzed gas mixes [3]. The mine devices based on this method, work in infra-red area of a spectrum with use of the optiko-acoustic phenomenon (occurrence of acoustic fluctuations in gas at absorption by the given gas of a faltering stream of radiant energy). Therefore the mine gas analyzers based on optical absorption  measurement method principle, name either opticс-acoustic, or infra-red gas analyzers.

Now in overwhelming majority gas analyzers infra-red radiation in a range 2-10 microns is used. Molecules of all gases (except for some two-nuclear - Na2, О2, Н2, etc., which molecules have dipole no moment) possess ability to absorb infra-red radiation. Thus each gas has the (characteristic only for it) absorption areas.

The review of the cores a component and the generalised block diagramme of a spectral infra-red gas analyzer

In structure of the typical spectral device enter (fig. 1) a source of the radiation 1, transferring optical system 2, dispersion the device 3 (the device for radiation decomposition into a spectrum), reception optical system 4, the receiver of radiation 5 and the registering device 6.

Figure 1 - The generalized block diagramme of the spectral device

Working out of the optical scheme of a measuring instrument of concentration of methane

Having analysed merits and demerits of existing measuring instruments gas a component, based on optical absorption measurement method we will develop the functional optical scheme of a measuring instrument of concentration of methane for conditions of coal mines of Donbass which is resulted in drawing (fig. 2)

Figure 2 - The functional optical scheme of a measuring instrument

Concentration of methane

  The source radiations (ИИ) forms with lens(Л1) the directed uniform stream of radiation which takes place the open optical channel (ОК) with measured concentration of methane (ССН4) in atmosphere of collieries. On focusing lens (Л2) the weakened stream of radiation by processes of absorption of infra-red radiation which bears the information on concentration of methane in OK. Lens Л2 arrives focuses a radiation stream in a window of a photo of the receiver (ФП) which will transform the received stream to an electric signal. The electric signal from ФП which contains the information on concentration of methane, arrives on measuring system (ИС) a developed gas analyzer.

Conclusions

Methods existing today and gauges of concentration of methane do not provide necessary speed of devices of measurement of concentration of methane in atmosphere of coal mines. Use optical absorption method and as modern means of optics and microelectronics will allow to create the high-speed device for definition of concentration of methane with the improved metrological and operational characteristics.

Literature

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http://www.uran.donetsk.ua/~masters/2004/kita/pogorzhelskiy/diss/index.htm

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