SANDA BUDEA, CORNELIA MARIETA CHIUJDEA POLYMER ADDITIVES IN HYDRO PRESSURE INSTALATIONS AND HYDRAULIC MACHINES The article presents the importance of using polymer additives in the hydraulic fluid flow, to reduce the friction, to reduce the linear pressure losses, to increase the flowing velocity, to reduce the pumping energy, to increase the efficiency of the hydraulic machines. The article highlights the Toms effect in hydraulic industrial applications. Its also shows experimental results on single stage centrifugal pump operating with additives in water in different poly acryl amide concentration, highlighting the significant increase of the pump efficiency when the concentration does not affect the fluid viscosity. The pump efficiency increased with 8-10% when the polymer additives concentration was 0,04%. Experiments were performed in Hydraulic Laboratory of University Politehnica of Bucharest. Enhancing theoretical and experimental research in this area, based on the viscosity and elasticity anisotropic properties of the polymer additives solutions, can be created new premises for hydrodynamics and hydro power applications.