Patent ID: 8522824

Claim:
An aseptic or sanitary diaphragm valve comprising: a flat lower plate of which an upper side has a first round opening leading to a first tubular port on a lower side of the plate, and a second opening leading to a second tubular port on the lower side of the plate; a flat upper plate generally coextensive with said lower plate and spaced above it and sealably joined thereto so as to define a sealed flow space therebetween sealed off from the ambient, the upper plate having at least one cylinder therein situated above said first opening and in register therewith, the cylinder extending upwards above the upper plate and having a lower side facing said first opening; a piston within said cylinder and movable between raised and lowered positions; a clamp removably joining the flat lower plate and the flat upper plate together in clamshell fashion to define said flow space therebetween; wherein said flat lower plate and said flat upper plate are cooperatively shaped and have respective mating circumferential flanges that permit the lower plate and upper plate to fit together in a sealed clamshell fashion with said flow space defined therebetween; a plate member affixed within said cylinder and extending across said cylinder below said piston and having a central bore therethrough; a valve member having a stem passing through the central bore of said plate member to connect to said piston, and being aligned axially with said cylinder and said first round opening, and having a lower valve plug at a lower end of said stem and aligned with said lower opening and adapted to close against same when the piston is in a lowered position and to raise away from the first round opening when the piston is in its raised position; a flexible diaphragm positioned below said plate member and extending across said cylinder above said flat upper plate, and with said stem penetrating said flexible diaphragm and being sealably affixed thereto, the flexible diaphragm being adapted to permit the piston to travel between its raised and lowered positions; and means for controllably applying a closing force to an upper surface of said first flexible diaphragm to urge the piston from the raised to its lowered position to effect seating of the valve member onto said first opening, and controllably releasing said closing force therefrom to allow the piston to rise from its lower position toward its raised position to permit lifting of the valve plug from said first opening.