The non-proportional flow problem of hydraulic pumps with constant pressure regulator in case of simultaneous work in Power Pack Unit with advanced multipump structure in open supply system is presented in the paper. Main parts of...

The efficiency problem of hydraulic pump units with advanced double structures with constant pressure regulators with different linear characteristics in the case of work in an open supply system is presented in the paper. The main parts of the hydraulic power pack structure and pressure controller functions are described. The equation is given for the calculation of energy losses in particular pumps and the whole multi-pump power pack unit. The difference between the efficiency of particular pumps and the hydraulic pump unit was discussed.

The corrosion influence on hydraulic pipelines safety mounted on product and chemical tankers has been presented in this paper. The issue of axial forces in pipelines mounted along ship open decks, resulting from ship hull deformations in waves, is highlighted. Corrosion degradation phenomena of hydraulic pipelines on open deck is described. The analysis of degradation effect on thickness of carbon steel material of pipes is given and influence of the effect on stress level increase in hydraulic pipelines during exploitation at sea is focused. The discussion about fighting against corrosion in hydraulic pipelines on open decks is performed. All the problems analyzed in the paper are based on examples of events observed on product and chemical tankers built in Szczecinska Shipyard, Szczecin, Poland.

The paper presents the results of experimental studies on distortion of the fixed plate edge due to formation of a butt joint. This is a hidden form of weld distortion present in structural nodes and identified at the ship hull pre-fabrication stages. The investigations were performed according to a design of experiment (DoE) approach in laboratory conditions resembling those encountered in the shipbuilding industry. The presented analysis includes the technological–construction parameters influencing the evaluated distortion shape. The implemented method of experimental results evaluation allows the utilisation of the approximation dependence to predict the fixed plate edge distortion in large-scale steel structures.