OS&Y (Outside Screw and Yoke)
A gate valve design where the stem threads are external to the valve body, outside the packing area. The rising handwheel visually indicates valve position - stem rising = valve opening. Preferred for critical services because the stem threads are not exposed to the process fluid.
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What is a OS&Y (Outside Screw and Yoke) in a valve?
A gate valve design where the stem threads are external to the valve body, outside the packing area. The rising handwheel visually indicates valve position - stem rising = valve opening. Preferred for critical services because the stem threads are not exposed to the process fluid.
What materials are used for the OS&Y (Outside Screw and Yoke)?
OS&Y (Outside Screw and Yoke) material selection depends on the process fluid, operating temperature and pressure, and required corrosion resistance. Standard materials include carbon steel (A216 WCB/A105), austenitic stainless steel (SS316/316L), and corrosion-resistant alloys (Hastelloy C-276, Inconel 625, duplex stainless steel 2205/2507) for aggressive service. All materials must be certified with EN 10204 Type 3.1 MTCs traceable to the heat number.
What standards govern the design of the OS&Y (Outside Screw and Yoke)?
Valve component design is governed by ASME B16.34 for pressure-temperature ratings, API 600/602 for gate valves, API 609 for butterfly valves, and API 6D for pipeline valves, as applicable. Third-party inspection to these standards ensures compliance. Vajra Industrial Solutions supplies valves with full documentation packages including dimensional inspection records and material certificates.
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