Inflatable Seated Butterfly Valves
Series 485, 486, 487, 488
ANSI and Metric Flange Compatible

Less friction, low torque, less wear, longer life.

Posi-flate's unique butterfly valve design uses air pressure to expand the seat against the disc, providing even pressure distribution for a bubble-tight seal, every time. Because the seat makes only casual contact with the disc during valve opening and closing, there is very minimal disc impingement. This is in contrast to conventional butterfly valves where disc impingement leads to shaving of the seat, decreasing the overall performance and valve life.Substantially less torque is required to open and close the Posi-flate butterfly valve, thus a smaller actuator can be used resulting in lower overall valve cost.In actual comparison tests and documented field applications, the Posi-flate butterfly valve outperformed all other valves. In fact, a Posi-flate valve life of one to three million cycles, even in extremely abrasive applications, is not uncommon. For dry solids, gases and slurry applications, the Posi-flate inflatable seated butterfly valve is unsurpassed.

Standard valve sizes range from 2” (50mm) to 30” (750mm) and fit both ANSI and metric flanges. A full line of actuators, limit switches and controls are available to suit individual applications.
Performance Features
  • Inflatable seat compensates for disc and seat wear
  • Longer valve life
  • Minimal seat wear
  • No disc impingement
  • Ultra-low torque requirements
  • Lower actuator costs
  • More seal contact area
  • Proven excellent for abrasive and dry solids
  • Disc designed to prevent material build-up
  • Double shaft seals
  • Multiple bearings
  • Fail-safe monitoring

Temperature limits: -40° to 300° F (-40° to 150° C), varies with application and materials of construction.

Air supply: 115 PSIG (7.9 bar) maximum to seat, varies with application.

Working pressure: Full vacuum to 100 PSIG (6.9 bar), varies with materials of construction.

Operating torque: Varies with application.

Available Materials of Construction

Housing: Cast iron, stainless steel, aluminum, nickel-plated cast iron, epoxy coated cast iron, nylon coated cast iron.
Resilient Seat: EPDM, Buna-N, polyurethane, FDA silicone, FDA white Buna-N, fluoroelastomer.
Disc: Cast iron, 316 stainless steel (satin or polished), molded nylon. PTFE, nickel and nyloncoating available.
Disc Screws: Carbon steel, stainless steel.

Bearings: Nylon, bronze
Shaft: Zinc-plated carbon steel, 316 stainless steel.
Shaft Seal: Buna-N, Viton®
Housing Gasket: Buna-N (Series 486, 487, 488).
Retaining Ring: Carbon steel, stainless steel.
Housing Bolts: Carbon steel, stainless steel.


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