Proportional Valve With Axial Flow And Rotational Metering

This paper presents a new concept hydraulic valve that tries to overcome a well-known poser affecting the pilot operated proportional valves, the flow forces. Despite of the traditional compensated profile spool valves, the basic idea is to design a valve that has as few mobile surfaces as possible. This assumption modifies the traditional valve design method and opens to new possibilities for the proportional valves. The solution presented in this paper uses an axial flow valve, where the oil gets through the valve across its axis, with two rotating surfaces causing a rotational metering. The result of this new design approach shows several advantages with respect to the common spool valves, such as the extremely compact size and the device versatility. This particular valve can realize the majority of the functions achievable using a two-way two-position proportional valve piloted by two pressure signals (for example a pressure compensated valve); the axial flow and the "built-in" metering edges yield the possibility to produce this valve as a cartridge component, whit all the advantages incidental to this type of devices. Some Computational Fluid Dynamics Analysis confirm the prediction of a low affection of this valve by flow forces, this attitude makes the axial Flow and Rotational Metering Valve particularly suitable for the local compensation in Flow Sharing Load Sensing distributors.