Hydrostatic drive in temporary bridges research. Research concerning strength and service life of bridge constructions requires using an input function with quite high value. This paper describes stations for testing bridge spans. Author presents his own station with hydrostatic drive used to unload tested span of temporary bridges.

Dynamic pressure changes in the hydraulic system of powered roof support. The paper describes a preliminary study on the changes of pressure in piston rod and bottom chambers of powered roof support, occurring during hydraulic control. It was emphasized that the type of valve used in the hydraulic system of such section influences on the pressure variation. Presented results confirmed the need for careful selection of hydraulic components with respect to their characteristics.

Optimal multi-edge seal. The paper presents a new seal – third-generation DryFlex®. It has been pointed out to the universal design, combining the advantages of seals made of soft materials and metal materials. They are also suitable for flanged connections of industrial pipelines, as well as heat exchangers. The paper describes two versions of designed seal and highlights their operational advantages.

Effect of solids and water contaminations to work of mining equipment. The papers describes the phenomenon of contamination of fluids used in the mining industry as a threat to the operating machinery. It is necessary to take into account the appropriate filtration systems during the design stage. The paper presents the criteria for the selection of filtration in terms of performance, investment costs and the possibility of installation of the system.