Abstract: An improved check valve is disclosed, which prevents the valve disk from slamming against the valve seat when the fluid flow in the line is suddenly reversed. The valve includes a disk and a seat, the disk being movable towards and away from the seat in response to pressure changes in the line. The disk, together with a central member, defines a chamber which becomes filled with fluid when the disk moves away from the seat. When the direction of flow in the line is suddenly reversed, causing the disk to move back towards the seat, the disk is cushioned by the fluid in the chamber, and does not slam against the seat. In one embodiment, an orifice is provided, spaced apart from the central bore of the valve, through which the fluid in the chamber can slowly and steadily leak out. In another embodiment, the orifice is provided in the disk of a pilot valve, which is a small check valve mounted at the inlet end of the main valve.

Abstract: An improved check valve is disclosed, which prevents the valve disk from slamming against the valve seat when the fluid flow in the line is suddenly reversed. The valve includes a disk and a seat, the disk being movable towards and away from the seat in response to pressure changes in the line. The disk, together with a central member, defines a chamber which becomes filled with fluid when the disk moves away from the seat. When the direction of flow in the line is suddenly reversed, causing the disk to move back towards the seat, the disk is cushioned by the fluid in the chamber, and does not slam against the seat. In one embodiment, an orifice is provided, spaced apart from the central bore of the valve, through which the fluid in the chamber can slowly and steadily leak out. In another embodiment, the orifice is provided in the disk of a pilot valve, which is a small check valve mounted at the inlet end of the main valve.