Plast-O-Matic Series VBS 4 in. Self-Closing PVC Vacuum Breakers w/ Viton Seals

4 in.
2.00 LBS
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Series VBS Vacuum Breakers feature a corrosion resistant PFA encapsulated spring which acts on a poppet seal that neither sticks nor chatters. Maximum working pressure is 100 PSI @ 75°F (6,9 bar @ 24°C).

VBS Vacuum Breakers are available in Geon® PVC, Natural Polypropylene, Corzan® CPVC and Kynar® PVDF. No fasteners are used on Series VBS in 1½"" & 2"" sizes. External, non-wetted fasteners are used on Series VBS in 3"" & 4"" sizes and are 300 series stainless steel. The encapsulation is not ""adehered"" to the spring. It flexes independently of the spring and does not crack or flake the way coatings can. This encapsulation has been tested for over 1,000,000 cycles in laboratory conditions with no ill effects. Series VBS seals are EPDM or FKM (Viton).

Threaded connections are standard on all models. Socket ends, BSP threads, JIS and DIN connections are available on all sizes and materials. Outlet connection is shipped with standard dust cap. Cap is removable for applications where pipe connection is desired due to location, potential hazard, etc. The outlet connection is identical to the connection on the system side of the valve.


  • Designed to protect enclosed tanks from collapse or structural damage during draining.
  • Eliminates siphoning of dangerous fluids.
  • Prevents vacuum which can cause damage to sensitive instruments and filters.
  • Normally-closed design prevents fugitive emissions from leaving system.
  • Ensures against replacement of damaged expensive equipment and avoids critical system downtime.
  • Patented diaphragm design assures dependable, repetitive, bubble-tight sealing in VBM and VB; PFA encapsulated spring and special poppet provide identical performance in VBS design.
  • For corrosive or ultra-pure liquid applications.
  • Sizes: 1/2", 3/4", 1", 1 1/2", 2", 3" and 4".
  • Materials: PVC, CPVC, Polypro, PVDF, PTFE
  • Threaded connections are standrad, socket connections are available.