Segmented or V Ported Ball Valves

Metso Neles segment ball valve

Ball, plug and butterfly valves all belong to a class of valves commonly referred to as "quarter-turn" valves. This refers the 90 deg (angular) rotation required to go from full closed, to full open position.

In most cases standard ball, plug, or butterfly valves are not the best choice as control valves (where the process media has to be modulated or throttled). Standard ball, plug and butterfly valves usually introduce very non-linear, dynamic flow coefficients. Furthermore, they can introduce undesirable turbulence to your piping system.

As a means to linearize flow coefficients and reduce turbulent flow, the machining, or characterization, of the valve disk is done so that the machined shape allows for more optimized flow.

For ball valves in particular, machining the ball's flow port with a "V", or even by machining the ball more radically, can deliver excellent flow curves. A term for a more radically machined ball is the "segment ball" (sometimes called "segmented").  In the following video you can see how a Metso Neles segment ball valve is designed to provide excellent control.

For more information about Metso Neles valves, contact Mead O'Brien at  (800) 892-2769 or visit http://meadobrien.com.

A Valve Controller Designed to Operate on All Control Valve Actuators in All Industries

Neles ND9000

Metso's Neles ND9000 is a top class intelligent valve controller designed to operate on all control valve actuators and in all industry areas. It guarantees end product quality in all operating conditions with unique diagnostics and incomparable performance features. ND9000 is a reliable and future-proof investment with Metso FieldCareTM life-time support.

Features

• Benchmark control performance on rotary and linear valves
• Superior diagnostics and data storage capabilities
• Local and remote configuration
• Easy interpretation of diagnostics data
• Efficient mounting program for all types of actuators
• Low power consumption
• Available for HART, PROFIBUS-PA and FOUNDATION Fieldbus networks
• Reliable and robust design
• Device self diagnostics
• On-line, performance and communication diagnostics
• Hot swap support: possibility to install also on valves that are in process with 1-point calibration feature
• SIL 2 approved device

Benefits

• Minimize variability
• Open solution based on FDT technology
• Supports Electronic Device Description Language (EDDL) technology
• Total cost of ownership
• Easy to use
• Open solution
• Product relibilty
• Prevention and prediction

Applications

• ND9000 can be integrated with all major DCS systems
• Mounting kits for any 3rd party actuators
• Remote mounting
• SIL 2 approved
• Marine approved

Triple Eccentric Disc Valve, Metal Seated, with Flow Balancing Trim

Neles Triple Eccentric Disc
Valve, Metal Seated with
Flow Balancing Trim

TRIPLE ECCENTRIC SEATING PRINCIPLE

The disc of the valve is machined to close tolerances to create an elliptical shape similar to an oblique slice taken from a solid metal cone. When the valve is closed, the elliptical disc at the major axis displaces the seat ring out- ward, causing it ring to contact the disc at the minor axis. When the valve is opened, the contact is released and the seat ring returns to its original circular shape.

CONTROL STABILITY AND SUPERIOR TIGHTNESS

The S-DISC® control valve unit provides outstanding control performance and excellent long-lasting tightness in the same valve. The very simple and robust construction guarantees long trouble-free operation and maximum reliability.

The S-DISC design consists of a standard NELDISC® triple eccentric disc valve equipped with a flow-balancing trim. The trim has been located on the downstream side of the valve body. The ingenious idea of this design is to transfer fluid forces out of the disc to the body. 

Figures 2 and 3 illustrate the flow treatments with a concentric-type conventional butterfly valve compared to the S-DISC-design. The S-DlSC design offers stable flow control and reduced dynamic torque, noise level and vibrations. The dynamic behavior of the valve is very smooth and stable, which means less load on the shaft bearings, less required torque, smaller actuators and more economical control unit total costs. All of the excellent features of the standard NELDISC are available.

The most standard NELDISC can be easily modified to the S-DISC design, just by changing the flange ring.

FEATURES

• Excellent flow and control performance.
• Wide temperature range from -200 ... +600 °C /-330 ... +1110 °F.
• Reduced dynamic torque and noise.
• Mechanical and flow dynamic stability allows higher pressure drop service than a conventional disc.
• ASME 150/PN 20, ASME 300/PN 40 and ASME 600/
• PN 100.
• Sizes DN 80...1500/3"...60"

For more information, visit http://www.meadobrien.com or call (800) 892-2769 for immediate service.