Diaphragm valve

摘要

The valve comprises a first rigid layer, a second rigid layer and a flexible layer positioned between the first and second surfaces of first and second layers. A valve chamber is demarcated by a concave surface in the planar first surface and one surface of the flexible layer and at least one first fluid passageway in the first rigid layer opens into the valve chamber at the concave surface to alternatively apply a vacuum and pressure to it. A fluid chamber is demarcated by another surface of the flexible layer and a concave-convex surface in the planar second surface which comprises an inner circular convex portion and a concentric annular outer concave portion. At least two second fluid passageways in the second rigid layer open into the valve chamber at the convex surface. When a vacuum is applied to the valve chamber, the flexible layer flexes to space the other surface of the flexible layer apart from the concave-convex surface to permit communication between the at least two second fluid passageways and when a pressure is applied to the valve chamber, the flexible layer flexes to dispose the other surface of the flexible layer on the concave-convex surface to prevent communication between the at least two second fluid passageways.