Hemiwedge cartridge valve designed for critical service applications
Hemiwedge Valve Corp. introduces the new Hemiwedge cartridge valve with a mechanical-seal design for critical service applications. The valve utilizes aspects of ball valves, gate valves and 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 that 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 valves defining feature is its cartridge design, whereby all the valves 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.
The Hemiwedge cartridge valves are designed in accordance with ANSI B16.34 and are available with API 6D certification. They are available in sizes 2 inches to 10 inches, and in ANSI Classes 150 to 900 Class. Other sizes are in development. The valve is available in carbon steel, low-alloy steels, stainless steels, duplex stainless steel, superduplex stainless steel, Inconel, Hastelloy and Monel.