Metal-seated Valve Design Introduced for Critical Service Applications
Hemiwedge Valve Corporation has recently introduced the Hemiwedge Cartridge Valve with a revolutionary mechanical-seal design for critical service applications. The patented valve utilizes aspects of ball valves, gate valves, and even triple-offset butterfly valves to protect the sealing surface during valve operation. A tapered hemispherical closure member (the hemi) rotates around a fixed core and wedges into a fixed seat to affect a mechanical seal. The closure member is rotated a quarter-turn by a valve stem which may be operated manually with a wrench or gear operator or automatically with a pneumatic, hydraulic or electric actuator.
Unlike designs with a rotating ball or plug, the Hemiwedge Cartridge Valve features a constant fixed core within the body to provide protection of the seating surfaces when the valve is opened, as well as minimizing turbulence as the valve is either opened or closed. This constant fixed core directs the fluid through the valve and not at the seats during the opening and closing of the valve. The most recent addition to the Hemiwedge Cartridge Valve line is an all-metal seat design that provides valve closure tightness to ISO 5208:2008 Rate B.
The Hemiwedge Cartridge Valve's defining feature is its ‘cartridge design' whereby all the valve's internal parts (core, hemi, seat, stem, bushings) are affixed to the bonnet and may be removed by unbolting the bonnet fasteners and lifting the cartridge from the valve body. Despite appropriate selection of hardfacing or coatings and despite protection of seats, severe service valves may still require routine maintenance. The cartridge provides a means of quickly and easily installing a pre-tested seat-to-closure member cartridge with no special tools, minimizing downtime and reducing maintenance costs.
Hemiwedge Cartridge Valves are designed in accordance with ANSI B16.34 and are also available with API 6D certification. They are available in two-inch to 10-inch sizes and in ANSI Classes 150 to 900 Class and other sizes are currently in development. The valve is available in carbon steel, low alloy steels, stainless steels and other materials such as duplex stainless steel, superduplex stainless steel, Inconel, Hastelloy and Monel.