Proportional pneumatic solenoid valve

A pneumatic solenoid valve comprising:

• at least two paths including a first inlet connected to a first pressure source and an outlet connected to a chamber at controlled pressure;
• a hollow body into which emerges each of the paths which communicate selectively with at least one other path;
• and an electromagnet secured to the body and including a core plunger capable of actuating means suitable for establishing said selective communication;
• and a second inlet connected to a second pressure source,
• the pressure of the first pressure source being relatively high, and the pressure of the second pressure source relatively low, and the means suitable for establishing said selective communication comprising a stationary valve and a movable valve housed in the hollow body, the stationary valve being open when the movable valve is closed, and vice-versa, characterized in that the second inlet is located beyond the first inlet with respect to the outlet and in that the means suitable for establishing the selective communication further comprises:
• a shaft formed inside the hollow body along an axis in an extension of the outlet and carrying a first valve element of annular shape pointing towards the outlet, extending in a plane which is substantially perpendicular to the axis and intended to interact with a second valve element to form with the second valve element said stationary valve;
• a third valve element formed at the periphery of a sealed surface and capable of being displaced by the core plunger of the electromagnet, along the axis and toward the outlet, so as to interact with a fourth valve element and to constitute with the fourth valve element said movable valve, the third valve element extending in a plane which is distant from the stationary valve and substantially perpendicular to the axis, and;
• a tubular and movable stopper member a first end of which carries said second valve element and a second end of which carries said fourth valve element, the second valve element being urged in the direction of the first valve element at least by a return spring and toward a position for closing the stationary valve in which the stationary valve, the shaft, and the stopper member together prevent any communication between the first inlet and the outlet while, in the absence of actuation of the electromagnet, allowing a communication between the second inlet and the outlet through the movable valve and, with the third valve element urged by actuation of the electromagnet, in the direction of the fourth valve element, into a position for closing the movable valve in which the movable valve and the sealed surface prevent any communication between the second inlet and the outlet while allowing, at least for a minimum predetermined actuation force of the electromagnet, a communication between the first inlet and the outlet through the stationary valve, the stopper member in any position preventing any communication between the two inlets.