The Valtek® Mark EightTM control valve is designed with a unique “Y” style globe body that provides higher flow capacities and less process turbulence than conventional globe valves.
Because of its nearly straight-through fl ow passage, the “Y”style body is less fl ow restrictive than a normal globe-style body. This permits less pressure to be converted into velocity as the fl uid passes through the seat, resulting in a lower valve recovery factor and higher capacity. Table I on page 3 gives nominal CV values for Mark Eight valves.
Mark Eight’s straight-through design generates less valve and piping turbulence which signifi cantly reduces harmful noise and vibration levels.
Like the Valtek Mark One globe valve, the Mark Eight features streamlined, constant area fl ow passages, top-entry trim, a four-way positioner, and a high thrust cylinder actuator. The Mark Eight is completely interchangeable with the Mark One except for the body, seat retainer, bonnet, and plug. The packing box, actuator, seat ring, fl anges, and gaskets are all standard, off-the-shelf items for fast delivery and minimal parts inventory.

Features and Benefits

• Lower valve recovery factor and higher Cv per given size over traditional globe style valves due to the nearly straight-through passage of the Y-style body
• Significantly reduced noise and vibration owing to less restrictive body style, which generates less line turbulence
• Easy, low-cost maintenance and extremely tight shutoff made possible by clamped-in seat and self-aligning seat ring
• Decreased inventory carrying costs from a high degree of interchangeability with Mark One Series valves