Search Results

You are looking at 1 - 5 of 5 items for

  • Author: Pavel Prokop x
Clear All Modify Search
Open access

Pavel Zapletal, Pavel Prokop and Vítězslav Košňovský

Abstract

The main subject of this paper focuses on scientific and research activities conducted in the Institute of Mining Engineering and Safety of the VŠB-Technical University of Ostrava. Cooperation between the VŠB-Technical University of Ostrava and OKD A.S., the only representative of coal mining in the Ostrava-Karviná coal basin, has recently begun to develop again. This paper describes an example discussed in a certain study, which has been undertaken for the Paskov mine, OKD a.s., dealing specifically with the evolution of microclimate parameters in mines that depend on the progress of mining activity at deeper levels over a period of several years. To this end, a special program, aimed at determination of the necessary refrigerating capacity, was established at the VŠB-Technical University of Ostrava.

Open access

Pavel Zapletal, Pavel Prokop and Václav Dorazil

Abstract

The regulation of mine ventilation by changing the operation of the main fan (HV) has both positive and negative aspects. One of the positive aspects is that this regulation can be made directly on the mine surface without lowering into the mine, namely by turning the fan blades from the minimum to maximum position. This regulation can be performed either from the control room or directly at the fan.

The utilization of this control method in the mine ventilation (the reducing or increasing of the depression of main fans) brings with also certain disadvantages. By the overall regulation of the depression of main fans we influence the overall mine ventilation network. The HV regulation can without further interventions cause problems in other part of the mine. Therefore, to eliminate the negative effects we have to do partial steps in the regulation of ventilation in the ventilation network to achieve the desired effect in a specific part of the mining field and prevent the unwanted effect in other parts of the ventilation network. In this article we deal with the negative effects on a face worked under the main haulage level

Open access

Aleš Prokop, Kamil Řehák, Martin Zubík and Pavel Novotný

Abstract

The noise, vibration and harshness (NVH) plays an important role in the transmission area of automotive industry. To understand all the impacts on the gearbox’s global dynamic behavior it is necessary to gain information from a simplified model, create methods and get an appropriate and well correlated results with the experiment. The method itself can be afterwards reused for more complex transmission, which could be supported by other measurements. This paper deals with creation of a gearbox’s simplified model, including essential mechanisms as gear mesh stiffness, backlash, bearing stiffness and modal properties of the main components. Except for the presented model, more models with different difficulty levels are used. Numerical results are compared with data from experiment with good correlation.

Open access

Pavel Zapletal, Pavel Prokop, Martin Štemberka, Beáta Gibesová, Eva Vavříková and Helena Trčková

Abstract

The Paskov Mine belongs to the company OKD, a.s. with the production of hard coking coal from 1970. The applied mining method is the slabbing method in controlled caving, excavating the coal pillar by means of coal plough equipment loading mine run on rake conveyers and securing the excavation area with individual hydraulic or mechanical supports. The coal face is planned as one of the coal faces in continuous extraction of the seam by a shearer.

Using the shearer at mines in the Paskov Mine is not a novelty. Shearer mining represents some problems. Besides the hazard of methane-air ignition, there is a mixture of coal dust - methane - air, which is more dangerous even in the case of lower concentrations of dust and methane than their individual lower limits of explosiveness. A decision was made then that shearers would gradually be replaced with coal ploughs in all coal faces.

The article contains the calculation of the volume of methane emitted as a result of excavation, determining methane concentration during excavation, lowering the hazard of methane layers being formed, and finally evaluating the suitability of the proposed system of the coal face ventilation.

Open access

Pavel Novotný, Václav Píštěk, Lubomír Drápal and Aleš Prokop

Shrnutí

Vývoj moderních pohonných jednotek vyžaduje využívání pokročilých výpočtových metod, nutných k požadovanému zkrácení času tohoto vývoje společně s minimalizací nákladů na něj. Moderní výpočtové modely jsou stále složitější a umožnují řešit mnoho různých fyzikálních problémů. V případě dynamiky pohonných jednotek a životnosti jejich komponent lze využít několik různých přístupů. Prvním z nich je přístup zahrnující samostatné řešení každého subsystému pohonné jednotky. Druhý přístup využívá model pohonné jednotky obsahující všechny hlavní subsystémy, jako klikový mechanismus, ventilový rozvod, pohon rozvodů nebo vstřikovací čerpadlo, a řeší všechny tyto subsystémy současně i s jejich vzájemným ovlivněním. Cílem článku je pomocí vybraných výsledků prezentovat silné a slabé stránky obou přístupů. Výpočty a experimenty jsou prováděny na traktorovém vznětovém šestiválcovém motoru.