VRA

Low pressure control valve

This large capacity pressure reduction valve is mainly used in large CHP plants, like desalination for turbine extraction control valve and LP dump to condenser applications. It is beneficial where supercritical pressure drops exist in some conditions in combination with low pressure drop in other conditions.

The IMI CCI VRA has been designed to provide high capacity at low pressure drops, tight shut-off to minimise heat losses, and very high rangeability. The IMI CCI VRA is available with IMI CCI desuperheaters.

VRA type valves are high capacity pressure reducing valves. The steam flow is throttled through a fixed cage with multiple drilled holes and a moving plug internally, which provide optimum characteristics for control of the steam pressure. The plug slides in a surface hardened body, thus uncovering a greater or smaller number of the throttling holes. In the closed position the plug seats on the hard-faced seat. The facing is made of a tough material with excellent sealing properties and good resistance against corrosion, erosion and thermal fatigue.

• All internal parts of the valve can be removed without the valve having to be dismantled from the pipe. The valve seat is designed for field replacement.
• The outer cage doubles as a strainer to protect the seat area from foreign objects.
• The plug connects to its actuator via a straight stem. The plug and stem are made of heat and corrosion resistant material, hardened in a unique process. The stem is sealed with a conventional stuffing box.
• The pressure reduction continues in the outlet that is furnished with pressure reducing pipes.