IT1247598B - Circuit for controlling flow rate and pressure of a hydraulic fluid by means of controlling the opening and closing time of valves - Google Patents

Abstract

Prior art: Continuous regulation of flow rate and pressure of hydraulic and oleodynamic fluids has thus far been obtained by throttle valves that create variable load losses in the fluid passing through them. Such valves are called servovalves, proportional valves or distributors, depending on the type of electrical or manual control and their response rate. The overall yield of oleodynamic systems is actually much less, the higher the degree of variability of the load and the simultaneity of the required movement. It is therefore complex and laborious to keep the yield of acceptable values in systems in which multiple hydraulic consumers simultaneously require speed and/or flow rate control. It is not possible in the present circuits to recover the energy that the load, in the deceleration or descent phase, would be capable of returning to the system; very frequently it is therefore necessary to also supply energy in the braking phase. The hydraulic circuit of the present application permits continuous control of the pressure and flow rate of the fluid without using throttle valves and consequently without a loss of load necessary for control by means of controlling the opening time of an electric valve. A circuit that also permits recovery of energy that the load to which it is applied is capable of returning to the system in the deceleration or descent phase.