The most efficient hydraulic power source is a variable displacement pump. Figure 1 shows a diagrammatic arrangement of a pressure compensated variable displacement pump which supplies fluid to the system at constant pressure and varying flow. In a variable displacement pump the rate of flow is controlled by operating the delivery control lever which in [...]
A more efficient supply system employing some additional components, is shown in Fig. 1. The additional components are: an accumulator, an off loading valve and a non-return valve. On start up the bypass line is closed and, as the pump charges the accumulator, system pressure rises; when the pressure reaches a value corresponding to the [...]
Typical arrangements of a constant pressure supply are shown in Figs 1. In its simplest form, shown in Fig. 1, the power unit consists of a fixed displacement pump, a pressure relief valve and a reservoir. As the pump delivers fluid at a constant rate. The supply pressure is determined by the setting of the [...]