Performance advantage 
Bellow is the key part of bellow sealed valves, which is
welded to both the valve bonnet and valve stem, with
automatic roll welding. The metal bellow can keep the stem
part 100% no leakage.
Double seal design (bellows+packing). Bellow form a metal
seal to prevent leakage, and packing can provide seal if the
bellow failed.
Design feature
Bolt Bonnet (BB)
Welded bonnet (WB)
Outside screw and yoke (OS&Y)
Technical specifications
Design standard: API 602; MSS-SP-117
Connection ends:
(1)Socket welded end: ANSI B16.11
(2)Screw end: ANSI B1.20.1
(3)Butt-welded end: ANSI B16.25
(4)Flange end: ANSI B16.5
Face to face dimension: ASME B16.10
Flanged ends: ASME B16.5
Welded ends: ASME B16.25
Test&inspection: API 598
Application
Thermal oil system, steam system, hot and cold water system,
etc