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On the preparation of precursors and carriers of nanoparticles by water jet technology
Sitek, Libor ; Foldyna, Josef ; Martinec, Petr ; Klich, Jiří ; Mašláň, M.
High-speed water jet expanded into many fields of human activity over three decades due to its unique properties. Besides already traditional technological processes (cutting, machining, cleaning, demolition, etc.) it begins to find its way also to the comminution of mineral particles. The paper analyzes the possibility of particle comminution using an abrasive mixing head used to generate high-speed abrasive water jet and an impact of the jet to the solid perpendicular target made 256 from tungsten carbide. Phyllosilicate (i.e. layered silicate) particles of both micron and submicron sizes were made by this method. The particles are disintegrated along the cleavage surfaces. The method avoids the formation of secondary structural defects which is in contrast to mechanical methods of particles comminution (such as planetary milling, ball milling, milling by pressure air etc.).
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Innovative Approach to Advanced Modulated Waterjet Technology
Kušnerová, M. ; Stoic, A. ; Foldyna, Josef ; Sitek, Libor ; Magurová, D. ; Harničárová, M.
The paper deals with a new formulation of theory for modulated waterjet technology by analytical model. The fundamental oscillations frequency for modulated waterjet technology has been investigated. This system generates a modulated liquid jet as a result of the resonant chamber introduction. The theoretical model was developed particularly on the basis of knowledge of the geometric dimensions of the system and the liquid pressures in order to predict the values of the fundamental frequencies of oscillations. The predicted oscillation frequencies were verified by laboratory measurements. It has been achieved a significant performance improvement in surface disintegration of material being machined.
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Water Jet 2011 - Research, Development, Applications (Proceedings of the Conference on Water Jetting Technology)
Sitek, Libor ; Zeleňák, M.
Conference Water Jet 2011 – Research, Development, Applications represents the second meeting of producers, users, designers and other people interested in technology of high speed water jet in the Czech Republic; it is a follow up to the successful first meeting held in 2009. The conference is organized by the Department of material disintegration of the Institute of Geonics of the ASCR, v. v. i. in Ostrava. With respect to the significant contribution of the International Visegrad Fund project to the activities related to the preparation and organizing of the conference, this year it was possible to hold the conference in the mountain hotel Sepetná in Ostravice at the foothill of the highest mountain in the Moravian– Silesian Beskydy Mountains – the Lysá Mountain. A wide spectrum of problems which are solved in submitted papers shows the recent trends in the application of the water jet technology in a great variety of branches of human activities. The considerable number of foreign participants of the conference proves the increasing interest in the technology in the whole Euroregion.
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Testing of Nozzles
Foldyna, Josef ; Sitek, Libor ; Ščučka, Jiří ; Klich, Jiří ; Hlaváček, Petr
Based on the request made by the company NET Ltd. Staré Město pod Sněžníkem, tests of quality of nozzles for generation of high-speed water jet were performed at the Department of material disintegration of the Institute of Geonics AS CR, v. v. i., in Ostrava. Three nozzles provided by NET were tested. The nozzles were marked as nozzle CKM – A, nozzle CKM – B, and nozzle ACMK. The nozzle quality was evaluated by the determination of their discharge coefficient at various operating pressures and by visual inspection of the quality of the nozzle and the water jet.
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New possibilities in the area of using of water jet technology for the removal of concrete surface layers
Bodnárová, L. ; Hela, R. ; Foldyna, Josef ; Sitek, Libor
The contribution deals with problems of using of water jet technology for the removal of concrete surface layers. Realized experimental tests were focused on the possibility of using of water jet technology in the stage of concrete surface preparation for the repair of concrete structures. The contribution specifies some new possibilities in the use of water jet technology for the concrete disintegration. The circumstances of surface layers removal through various types of water jet were investigated on concrete samples with different characteristics of surface layers. In the paper, possibilities of high-speed water jet technology are extended to the application of so-called flat water jet. Interesting results in relatively low energy demands can be achieved during disintegration of very hard concrete in conjunction with an acoustic pulse generator.
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