Abstract: A pressure intensifier for a fluid comprises at least three piston assemblies disposed along mutually parallel axes equiangularly disposed with respect to a central axis of the intensifier and radially equidistant therefrom. Each piston assembly has two opposed high pressure cylinders and low pressure cylinders. Fluid is supplied to the low pressure cylinders and discharged through a low pressure valve operatively coupled by a swash plate to the pistons of each assembly so as to be driven thereby. A high pressure collector, optionally in the form of a closed circuit, is provided for receiving high pressure fluid from the high pressure cylinders.