Ball Sector Valves
The valve for abrasive and slurry applications
Design principle ball sector valves
Ball sector valves provide outstanding performance in challenging applications. In a closed position conventional butterfly and ball segment valves expose their critical sealing components to the highest wear in the valve. Due to the special design of the ball sector, the seal seals through a surface part less exposed to wear. In order to avoid abrasion caused leakage, the ball sector valve facilitates sealing through less exposed areas of the ball sector. The fact that the sealing surface is not exposed to high flow velocities increases the service life of the ball sector valves significantly. The shaft is sealed using a self-adjusting PTFE packing with an integrated spring element that protects the bearing against media particles.
Durable under extreme conditions
Wear caused by abrasive media starts at the control edge of the throttle. The sealing surface on the ball sectors is far away from the control edge of the ball sector and is not exposed to high flow velocities. Even heavy wear therefore leads to leaks much less frequently and later than with rotary globe valves. This beneficial sealing concept, combined with different materials and surface treatments for the valve seat, is the basis for long service life and reliable operation, particularly in applications with abrasive, highly viscous or fibrous media.
Excellent rangeability
Ball sector valves have a very high rangeability of 300:1 and therefore enable precise control over a wide control range. Combined with high-resolution actuators, the most demanding control tasks can thus be managed.
No clogging or draining with fibrous media
Ball sector valves have an elliptical flow opening, which means that even small flow rates of fibrous media (e.g. paper pulp) can be controlled without draining or clogging the valve.
Wear-resistant thanks to protected sealing surfaces
Due to their central bearing, the ball sectors maintain continuous contact with the seat seal during rotation. Contrary to eccentric standard rotary globe valves, the sealing surfaces of ball sector valves are therefore protected against the attack of abrasive media even in the open position. Furthermore, solids from the medium cannot get jammed between the ball sector and the seat ring and cause damage.
Unlike ball sector valves (left), rotary globe valves (right) lift off the seat seal when rotating. This often results in damage to the sealing surfaces of the rotary globe valves due to abrasion and jammed particles.
High and variable CVmax. values
When open, ball sector valves allow the media flow to pass through almost the entire nominal pipe diameter. They therefore achieve very high CVmax. values and do not deflect the flow.
Because of the different flow openings of the ball sectors, the CVmax value can be adjusted precisely to the requirements of the respective application.
