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Valves; HF Alkylation Service
Listed below are more detailed outlines of these sections in The MSS SP- 160 Standard:
Scope, Valve Design, Materials, and Definitions Scope applies to gate, globe, check, butterfly, and plug valves. It does not apply to valves used in hydrogen fluoride acid production.
All welds shall be made to weld procedures, set and qualified by welders to the ASME, ISO, and NACE.
There are options for grease injectors, nickel-lined packing stuffing boxes, check seal welded hinge pin plugs, and PTFE soft seats. Plug valve( cap / stem) designs, for instance, are to be implemented to prevent water accumulation. Gear operator options are outlined in this section as well.
Foundry Requirements, Welding, Welding Repairs, and PWHT Foundry requirements must be documented to foundry qualifications and 1st articles. Therefore, casting simulations are needed to determine discontinuities and pattern / rigging according to the simulation results.
Valve design includes many key standards, such as low emissions performance and compliance with industry design standards. For gate, globe, and check valves, the seat pocket is Alloy 400, and seats are installed into low RE carbon steel using a nickel butter pass layer. The seats are press-fitted and seal-welded to ensure a secure and leak-tight connection.
Materials to the American Society for Testing and Materials( ASTM) standards for cast and forged bodies, bonnets, and covers are low RE carbon steel, Alloy 400 and C276. Cast and forged materials of components are to ASTM standards( with some specific components to different materials). Bolting, lubricants and anti-seize directives are also included in the document.
Shrinkage or microporosity are not allowed through ¼” wall thickness based on simulation or final NDE on machined surfaces. Any foundry changes must go through a new casting simulation, and partial furnace changes are not permitted.
All welds shall be made to weld procedures, set and qualified by welders to the American Society of Mechanical
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