Butterfly valves: VSS
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Datasheet Butterfly valve Type VSS Wafer design Nominal pressure PN 10 - 25 Nominal size DN 80 - 1200 Material Stainless steel triple • Advanceddesign eccentric • Designed for control and shut-off applications • Designed forup to applications 350° C (662 °F) • Tightness class inEN accordance with 60534-4 Class V as standard made • Solid seatsteel of stainless • Wafer design (Mounted between flanges) alt. lugged design • PTFE-seat • High temperature applications up to 550° C (1022 °F) SOMAS butterfly valves, type VSS is used as a control, on/off and shut-off valve. The VSS valve is designed to handle a wide range of liquids, gases and steam within a broad temperature range. The valves have an advanced triple eccentric design including a unique shape of the disc allows the use of a solid stainless steel seat. The solid seat remains unaffected by high flow velocities and temperatures. A good valve function is achieved even on difficult applications. The seat is replaceable in alternative materials. The VSS valve can be mounted between flanges and is also supplied in lugged design. The SOMAS valves are delivered ready for installation and operation. The valve assemblies are delivered factory tested as complete units with actuators, positioners and accessories.

Tightness class The tightness class is related to the chosen material in the seat ring. Pipe geometry factor FP Valve Metal seat Code C alt. D EN 60534-4 V (ASME B16-104 Class V) PTFE seat Code A EN 60534-4 VI (ASME B16-104 Class VI) (Option) Flow characteristics 100% Flow Liquid pressure recovery factor FL Factor Fl Factor Fl is valid for all sizes Factor Flp is valid for all sizes

Pressure and temperature rating Use shaft material according to material code A for temperatures up to 150° C. Use shaft material according to material code B for acids and hot gases above 150° C. Max. working pressure (bar) PN 6 10 16 25 Max. allowable pressure drops/torque figures Maximum allowable pressure drops are valid at 20° C (see below). Max. pressure drop. bar at opening angle

A = Face to face dimension according to EN 558 series 20 (valid for DN 100 - 1200) øde = Necessary free diameter for the disc under movement

X = SC – Spring to close X = SO – Spring to open For units with the positioner type SP405, add 2 kg For units with the positioner type SPE405, add 3 kg For units with the positioner type SP405, add 2 kg For units with the positioner type SPE405, add 3 kg

Manual override

Flange standard Further technical information SOMAS butterfly valve type VSS in this data sheet is of wafer type for mounting between flanges PN 10-25. Technical data for the materials used in the SOMAS valves, flange standard, steam data, etc. can be found in section 6 of the SOMAS catalogue. The valve can also be delivered in lugged design. See also data sheet Si-205, that shows butterfly valve type MTV (DN 80–500). For valves with pressure class PN 50, see data sheet Si-204. The valve can also be drilled for mounting be­ ween t flanges according to ASME. When ordering, please always...

Temperature range The standard VSS valve is designed to be mounted between flanges, but is also available in lugged design. Seat A = PTFE (10 % carbon) C = 1.4462 (metal seat, 3 pcs.) D = 1.4470 (metal seat type Y) E = 1.4547 P = PTFE (fibreglass 15 %) Shaft A = 1.4460 B = 1.4460, hard chromed F = 1.4435 G = 1.4435 (316L), hard chromed H = 1.4429 J = 1.4547 K = 1.4539 T = Titanium Ordering State desired valve according to the valve specification system below as well as type of actuator, positioner and accessories. Check with SOMAS for temperatures between 350 and 550° C. At higher pressures...