Pneumatic Incremental Proportional Valve

Abstract

Performant actuating systems use both classic and proportional valves. Proportional valves are based on an electro-mechanical actuator. The characteristic of the electro-mechanic actuator $x_{ia} = f\left( {x_{i} } \right)$ may be continuous or discontinuous. This influences the characteristic of the whole device. The use of a discontinuous actuator has some advantages, as: it can be used in open loop, it allows starting, stopping and inverting the rotating direction without losing steps, it memorizes the position and it is compatible with the numerical technique. The paper proposes a proportional valve containing a classic pneumatic control valve with preferential position and electric control, and a proportional device with a special construction. The proposed construction and the functioning of the device are described, and the flowing area variation is calculated. The static characteristic of the proposed valve is determined, and the real profile of the control cam is calculated.