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Gate Valves are available with different disks or wedges. Ranging of the Gate Valves is usually made by the type of wedge used.
The most common were:
•Solid wedge is the most commonly used disk by its simplicity and strength.
A Valve with this type of wedge can be installed in each position and it is suitable for almost all liquids. The solid wedge is a single-piece solid construction, and is practically for turbulent flow.
•Flexible wedge is a one-piece disc with a cut around the perimeter to improve the ability to correct mistakes or changes in the angle between the seats.
The reduction will vary in size, shape and depth. A shallow, narrow cut gives little flexibility but retains strength.
A deeper and wider cut, or cast-in recess, leaves little material in the middle, which allows more flexibility, but compromises strength.
•Split wedge is self-adjusting and selfaligning to both seats sides. This wedge type consists of two-piece construction which seats between the tapered seats in the Valve body. This type of wedge is suitable for the treatment of non-condensing gases and liquids at normal temperatures, particularly corrosive liquids.