Gate Valve Disk Design:

Gate valves are available along with a variety of disks. Categorization of gate valves is commonly made through the categorized disk used: flexible wedge, solid wedge, split wedge, or parallel disk. The flexible wedges, Solid wedges, and split wedges are used in valves having inclined seats. A Parallel disk is used in valves having parallel seats.

Regardless of the style of wedge or disk used, the disk is common replaceable. In services whereas solids or high velocity might cause rapid erosion of the seat or disk, these elements should have a high surface hardness and should have replacement seats as well as disks. Seat damage requires removal of the valve from the line for refacing of the seat if the seats are not replaceable, or refacing of the seat within place. The Valves being used inside corrosion service should generally be specified along with replaceable seats.