Valvitalia-Cryogenic Valves.pdf - sge.com.sa

A Long Experience in Energy Equipment and one Goal:The Customer’s satisfaction.G RO U PButterfly ValvesHigh PerformanceCryogenic Valves

®The Dyna-Lok difference in high-pressureflow control for cryogenic applications.The Dyna-Lok cryogenic valve representsa further development in flow controltechnology, extending the performancebenefits of Dyna-Lok valves into theregion of ultra low temperatures. Theannular space between the extendedvalve stem and outer tube has been heldto an absolute minimum to minimize heatloss. The bonnet has been extended toprotect the packing from low temperatures;a vent in the neck of the valve allowspurging of vapor. Both the valve body anddisc are made of austenitic 316 stainlesssteel for low-temperature strength andductility; the disc is nickel-plated to preventgalling. Due to its very low mass, thevalve also has adesirably low thermalcapacity. Beforeintroduction, extensive testing under realisticservice conditions confirmed thesuitability of Dyna-Lok cryogenic valvesfor dependable on/off and proportionalflow control for cryogenic liquids.Dyna-Lok cryogenic valves are designed for reliableDynamic, pressure-boosted sealing givestight shutoff in both flow directionsDisc closed, seal preloadedThe valve seat assembly consists of a Kel-F* seal ring with back-up seal energizer, aspiral wound member of Hastelloy * *strip. A static seal is created when thevalve closes and the seal ring is preloadedby the disc, imposing a load on the sealenergizer. The spiral wound energizercompresses slightly into an ellipticalshape, with its major axis parallel to thevalve centerline. This loading of the sealenergizer provides resilience for the sealring and promotes tight circumferentialsealing. A secondary seal occurs wherethe seal leg is locked between the valvebody and retaining ring.Pressurized, stem upstreamAs line pressure is introduced at the rightside of the seal cavity, the seal ring movesin direction A. This movement compressesthe seal energizer in a direction nearlyperpendicular to the static preload,increasing the spring force in direction B.Increased force in direction B is transmitteddirectly into greater sealing force atthe disc. As the seal ring is forced to theleft, specially angled surfaces C and D ofthe retaining ring direct its movementtoward the sealing face, increasing sealingeffectiveness.Pressurized, stem downstreamWhen the valve is pressurized from leftto right, line pressure enters the entireleft side of the seal cavity. The force producedby line pressure tends to rotatethe seal ring counterclockwise aroundthe seal leg pivot. This increases primarysealing force at the disc, as the seal ring ispressed more tightly against the disc contour.The greater the line pressure, thebetter the seal, within the operating pressurerange of the valve.VALVITALIA reserves the right to change design, specification and materials without notice2

G RO U PDouble offset, streamlined disc for bothon /off and throttling service.Through precise engineering of the disc,stem and seat, a double offset has beencreated.The center of disc rotation is offset fromboth the valve and seat centerlines, producinga desirable combination of operatingcharacteristics.As the valve opens, the disc lifts quicklyoff the seat, limiting the period of breakawaytorque demand and producing amore linear flow in the early stages of discrotation.The disc remains clear of the seat throughoutits throttling range, avoiding seatscuffing or deformation.As the valve closes, the disc makes nearlysimultaneous full-circle contact with theseat, automatically cleaning the seatingsurface and creating a tight circumferentialseal.performance to -425° F.Field-proven tough for demandingapplications.The reliability of the Dyna-Lok cryogenic valveengineering concept and development test programhas been proven through field applicationsin tough, demanding services. Numerous installationsin various cryogenic applications haveproven the valve's suitability to liquid natural gas,liquid oxygen, liquid nitrogen and othercryogenic fluids through a wide range of operatingpressures and temperatures.The Dyna-Lok cryogenic valve is readily availablein a broad range of body sizes and pressureratings to meet your needs for manual and automatedapplications for dependable on/off andmodulating control in cryogenic liquids.The Dyna-Lok product line includes a full selection of valvesand accessories for cryogenic applications.Wafer valveGear OperatorSingle FlangeValve,Lever OperatorStandard Product LineBody StylesWafer and single FlangeValve Classes and SizesClass 150 3” through 36”Class 300 3” through 24”Class 600 3” through 12”Materials of ConstructionBody 316 stailess steelDisc 316 stainless steel, nickel platedStem 17 - 4 PH H 1150 MStem/Disc Pins 17 - 4 PHSeal Ring Kel - FSeal Energizer HastelloyMaximum Rated PressuresFor Bidirectional shutoffClass 150 275 psigClass 300 720 psigClass 600 1440 psig3VALVITALIA reserves the right to change design, specification and materials without notice

A Long Experience in Energy Equipment and one Goal:The Customer’s satisfaction.Rivanazzano (PV) PlantG RO U PVALVITALIA S.p.A.Via Tortona, 69 - 27055 Rivanazzano (PV) ItalyPhone: +39.0383.945911 - Fax +39.0383.9459962E-mail: info@valvitalia.comWeb site: www.valvitalia.com03.10 - 500 - DYNACRYO.07