Fluid process control employs valves of various types to start, stop, throttle, or divert the flow of a fluid. Ball valves are a common selection for process application when their inherent advantages provide the greatest benefit.
- Leak-proof service
- Well suited for processes requiring only full flow or no flow operation.
- Rapid open and close action, requiring only 90 degrees of rotation from fully open to fully closed.
- Comparatively lightweight and compact size.
- A wide range of construction material options for body, ball, and seals make them suitable for many applications.
- Require only moderate force to control valve position.
- Flow path opening in the ball will often be “full port”, providing the same cross-section as the connected pipe and adding very little restriction or pressure drop to the flow.
- Low maintenance, with no lubrication required.
There are numerous ball valve variants that provide modified features and performance, but let’s focus on what is generally considered severe service applications.
Severe service, while not currently defined by an international standard, generally can be characterized by one or more operating conditions that put great levels of stress or wear on valves.
- Very extreme media or environmental temperature
- High-pressure drop operation that may cause cavitation
- Rapid and extreme changes to inlet pressure
- Certain types or amounts of solids contained in the fluid
- Corrosive media
Some of these conditions will greatly impact the valve seat. Many valves are provided with thermoplastic seats that, while providing suitable performance throughout a wide range of media conditions, will deteriorate quickly under conditions prevailing in severe service. An alternative to the soft thermoplastic seats is a metal seat design.
- Greater temperature tolerance
- Self-cleaning seat
- Improved resistance to effects of particulate-laden media or slurries
- Corrosion resistance, enhanced by special coatings applied to metal construction
The document below provides an in-depth view of a metal seated ball valve. Operating conditions, specifications, and illustrations (including my favorite, the cutaway view) are provided. Share your fluid control requirements with product and application specialists, combining your process expertise with their product application knowledge to develop effective solutions.