Pressure Seal and Bolted Bonnet Valves - 54 Pages

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Catalogue excerpts

Velan is one of the world's leading manufacturers of industrial steel valves, supplying gate,globe, check, ball, butterfly and knife gate valves for critical applications in the chemical, petrochemical, oil and gas, fossil and nuclear power, cogeneration, pulp and paper and cryogenic industries. See the back cover of this catalog for a summary of the many quality products that Velan designs and manufactures.Founded in 1950, Velan earned a reputation for excellence as a major supplier of forgedvalves for nuclear power plants and the U.S. Navy. Velan Inc. pioneered many designs which became industry...

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Velan holds all major applicable approvals, including ISO 9001:2000, PED, ASMEN/NPT, TV, and TA-Luft. Velanܒs comprehensive quality program is fully compliant with the most stringent industry standards and has been surveyed and audited by leading organizations, regulatory bodies, utilities and architect/engineers from around the world. Velans number one priority is quality. From order entry to design engineering to the shop floor, the entire company is totally committed to offering products and services that not only meet, but exceed customer expectations. All Velan valves are designed and manu-...

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All over the world,Velan valves are used by the worlds leading industrial companies to help keep their operating facilities running smoothly.In fact,Velan valves have a long history of proving themselves in many of the industrial worldҒs toughest applications. > Velan has supplied complete valving in sizes Velan pioneered many innovations such as forgedvalves to 24" (versus cast-ings) to resolve external and internal leakage, extend service life and reduce maintenance. > 1 / > 2 to 60" to over 2500thermal power stations around the world, for low and HP/HT service of up to 4500 psi and 1200F. > VelanВs...

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Pressure seal check valves installed in a nuclear power facility. Pressure seal valves used in oil and gas applications. 10 (250 mm) Pressure seal valve installed at ProfertilԒs plant in Bahia Blanca, Argentina. Pressure seal valve in a cogeneration power plant. Velan qualification testing program with lectricitɩ de France. >

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Flow testing on a 10Ҕ (250 mm) Class 1500 forged bolted coverswing check valve. Left: Velans QC Department testsan automated valve solution designed specifically for a leading international architect/ engineering firm, for turbine bypass inlet isolation. Velan used Computational Fluid Dynamics to improve the flow characteristics of this 4Ҕ (100 mm) globe valve.Right: A second generationgate valve developed byVelan to meet therequirements of a majorNorth American NuclearUtility in compliance with US NRC GL89-10 and EPRIPPMsizing requirements. >

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Automatic PTAW (Plasma Transfer Arc Welding). A large CNC horizontal boring mill (with tool changers)machining forged pressure seal bodies. >

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overall integrity of castings (to X-Ray Level II or better as a general standard). Note that high pressure castings (>900F/482аC) follow a far more stringent protocol (100% x-ray coverage and higher acceptance criteria.)An example of the successful cooperation of Engineering,our Casting Simulation Technologist and the foundry,using the Magmasoft > simulation, is shown below.Velan introduced our large diameter forged valves forhigh/pressure temperature applications over 40 years ago. Since then, we have become the market leader in forged pressure seal and bolted bonnet gate, globe and check valves...

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Velans pressure seal design has been optimizedfor and successfully field tested in tough powerapplications, including ғpeaking type cogener- ation plants or daily start & stop (DSS) / weekendstart & stop (WSS) plants where valves are subject to frequent start-ups and shut-downs. > Ԣ׏ Bonnet take-up bolts establish the initial seal of thepressure seal joint (body to gasket to bonnet) Velan offers graphite pressureseal gaskets as standard, instead of soft iron gaskets, providing a more flexible sealfor applications with fluctuatingconditions. (Silver-plated soft iron gaskets are available on request.)...

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EVOLVED FROM EXTENSIVE TESTING, OFFERS A TIGHT SEAL WITH LITTLE OR NO MAINTENANCE OVER LONG PERIODS OF TIME NON-ROTATING STEM LOWER OPERATINGTORQUE > has tight roundness and straight-ness tolerances and is burnished for a superior surface finish. due to non-rotating stem. Torque arm prevents rotation,indicates position and may also actuate limit switches. LIVE-LOADING(OPTIONAL) > Two sets of Bellevillesprings maintain aminimum permanentpacking stress of 4,000psi (275bar). Live-loading keeps thestem tight for long periods of time without maintenance. Bolt torques control total spring load. SHORT...

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Velan valves feature a formed multi-ply bellows weldedto the stem and to the bottom of the bonnet, creating a hermetic seal or impermeable barrier. Bellows are available in stainless steel, Inconel, Hastelloy C andMonel for virtually all corrosive chemical applications.Velan has extensive experience in valve live-loading. The original concept was developed by Velan in 1972 in a research project for Atomic Energy of Canada Limited(AECL) to eliminate leakage in Nuclear service. Velan hasbeen supplying live-loaded valves for Nuclear and non- Nuclear service for more than 30 years. > Live-loading...

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The potential for failure to open of wedge gate and parallel slide valves,under certain process conditions may be attributed to an increase in the required unwedging thrust to open the valve due to the following phenomena: > (Diagram A) > ● An equalizing pipe and equalizing valve (Diag.E) ,the valve must be open to provide relief. may result when liquid,entrapped in the center cavity of valves,is heated. > ● The trapped fluid expands and the resultant increase in pressure may render the valve inoperable. In extreme cases, a breach of the pressure boundary may occur. > ● NOTE: Relief valve Caution...

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(Diagram I) CAB > ● Verify the process to see if ∆T between closing andopening can be reduced (recommended ∆T≤150F). Closing hot and opening cold is a prescription for thermal binding. > Т׏ The shuttle is pushed to seat on the LP side. HP (High Pressure) on theBӔPort (Body Cavity): > ● The pressure is then equalized between the HPside CӔ and the body cavity BӔ. > ● After closing a wedge type gate valve, back up the stem ( > 1 / > 8 to > 1 / > 4 turn) to allow room for stem expansion.This is only practical in manual valves or electronically controlled motor operated valves. > Diagram I: Cut showing...

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