ST SERIES: 
Size: 1/4 to 2" (8 to 50mm) 
Pressure ratings: 150, 300, 600, 800, 1500 and 2500 lb. class, 

Constructional features: 
Bolt-on bonnet and open stem bracket type (150 to 1500 lb. class), 
Welded bonnet and open stem bracket type (800, 1500 lb. class), 
Threaded bonnet self-tightening Sealed (1500, 2500 lb class), 

The fully guided design of the valve flap ensures that the seat and flap are precisely aligned and protected from lateral thrust caused by high velocity fluids. This construction prevents the valve flap from abrading the valve body, scratching or bending the stem, and extends the life of the valve flap and seat. 

A large gap between the stem and flap allows the valve to move freely. 

Polished, hardened stem, packing cavity, and pre-pressurized combination graphite ring for reliable stem sealing. 

Two-piece sealing bushings are self-correcting. 

Solid tungsten-chromium-cobalt alloy flaps and seat rings are available to achieve reliable sealing, even in demanding applications. Solid tungsten-chromium-cobalt alloy valves and seat rings are available for long service life even in harsh applications. Valve vendor types are available in cutoff, modulating, or cutback. 

Handwheels are flanged for non-slip operation, even with gloves. 

Handwheels are available in a variety of colors. 

Application specifications: 
Design: ASME B16.34, API 602, 
Testing: ASME B16.34 and API 598, 
Marking: MSS-SP-25, 
Socket Weld Ports: ASME B16.11, Butt Weld Ports: ASME B16.11, MSS-SP-25, and MSS-SP-25. Butt Weld Ports: ASME B16.25, 
Threaded Ports: ASME 1.20.1.