Technical Specifications

21000 Series Control Valves Technical Specifications | 23
Standard Construction
Bellows seal configuration is fully compatible with the standard 21000 Series
trim and actuator options providing equivalent capacity capabilities for each
valve size. The standard packing box design and packing design options are used
as a secondary stem seal.
Rugged Design
The formed bellows construction is an externally pressurized design that is
capable of operating up to the full valve ANSI B16.34 pressure rating. Guides
are located above and below the bellows providing excellent stability to with-
stand flow induced and mechanical vibration.
Extended Life
The bellows assembly is designed for 50% compression/extension (zero stress)
at the valve mid-stroke position to help maximize cycle life. Bellows torsional
stresses are also reduced with the anti-rotation feature provided by flats on
the plug stem.
High Quality
Each bellows subassembly is helium leak tested to verify weld integrity, and is
also hydro-statically tested as part of the complete valve assembly. Mechanical
travel stops are also designed into both the bellows and valve assemblies to
prevent over compression or extension.
Smart Solution
Bellows installed cycle life can be monitored in the field by utilizing Masoneilan’s
SVI
*
Digital Positioner with actual process data. This advanced preventative
maintenance option will help improve plant safety by identifying potential
hazardous failures before they happen, and cut cost by reducing premature Bellows
replacement.
Bellows Materials
Standard Material
316/316L Stainless Steel
Optional Materials
Hastelloy C276
Monel 400
Inconel 625
100% 50%
Valve Size
Bellows Design Stroke
25%
Life Cycle Ratings
(1)
Maximum Stroke
.75 " -2 "
3 " -4 "
6 "
.75 19
1.50 38.1
2.00 50.8
inches
100,000
Full
Cycles
600,000
Full
Cycles
3,000,000
Full
Cycles
Size and Ratings
Pressure Ratings: ASME Class 150 and 300 – PN 20 and PN 50
1) Minimum expected average cycle life for Class 300 (PN 50) bellows operating at constant pressure.
2) Consult Masoneilan for Bellows applications above ASME Class 300 (PN 50).
mm
Bellows Seal Design Features
21000 BS Series
Temperature (C)
¨
¨
¨
¨
¨
¨
¨
¨
AISI 316 Bellows Rating Chart
Pressure (bar)
20 100 150 200 250 300 350 400
70
60
50
40
30
20
10
0
Size and Rating