Double membrane valve with interposed ring

A pneumatically actuated valve, comprising:

• a valve body including a shut off valve disposed therein;
• the valve body having a first shell and a second shell;
• an inlet duct extending from the first shell of the valve body and having an end wall open to an exterior of the valve body, the inlet duct configured for connection to a product source;
• an outlet duct extending from the first shell of the valve body orthogonally to the inlet duct;
• the shut-off valve acting to selectively interrupt or allow a connection between the inlet duct and the outlet duct;
• a control chamber defined between the first shell and the second shell of the valve body, and including:
• a first deformable membrane and a second deformable membrane which are adapted to form a flexible wall delimiting a closed, sealed space inside the control chamber and which operate on the shut-off valve;
• the first deformable membrane being rigidly coupled to the first shell;
• the second deformable membrane being rigidly coupled to the second shell;
• a spacing element interposed between the first deformable membrane and the second deformable membrane to define an intermediate chamber between the first deformable membrane and the second deformable membrane, the intermediate chamber being without fluid sealing;
• wherein the spacing element includes a plurality of through holes to promote a flow of fluid from the intermediate chamber to an external environment;
• wherein the shut-off valve further comprises:
• a shutter which acts on the end wall of the inlet duct to open and close the inlet duct and the shutter is operatively coupled to the first and second deformable membranes,
• a spring acting on the first and second deformable membranes for at least one chosen from returning the shutter to and holding the shutter at a position for closing the inlet duct;
• a stem including the shutter at a stem first end and the stem operatively connected to the first and second deformable membranes at a stem second end, and wherein the spring comprises a helical spring with a spring first end abutted against an inner side of the first shell and with a spring second end abutted against a side of one of either the first or the second deformable membrane facing the stem via the stem second end;
• wherein the inlet duct has a first end and an opposite second end defining the end wall, the first end facing towards one of the first and second deformable membranes and wherein the shutter acts on the inlet duct, at the second end;
• wherein the through holes are radial holes;
• wherein the through holes are configured to prevent negative pressure from being formed between the first deformable membrane and the second deformable membrane so that the first deformable membrane and the second deformable membrane do not adhere to each other;
• a mechanical coupling connecting the first shell to the second shell;
• the mechanical coupling including protrusions on one of the first shell and the second shell configured to mate with insertion holes on the other of the first shell and the second shell, the mechanical coupling being a non-fluid sealed coupling;
• and
• wherein the stem extends into the inlet duct and the shutter extends past the end wall of the inlet duct to the exterior.