Ventilating and bleed valve type 591 PVDF

  Datasheet (PDF)

The Georg Fischer SYGEF Standard Type 591 ventilating and bleed valve provides automated, bi-directional air management for industrial and high-purity thermoplastic piping systems. Manufactured from unpigmented polyvinylidene fluoride (PVDF), this valve is engineered for demanding applications handling aggressive chemicals, deionised water, and pharmaceutical-grade purified water across an operating temperature range from -20 degrees Celsius to +140 degrees Celsius. The valve automatically expels entrapped air during system filling and continuous pressurized flow, while instantaneously admitting ambient air during line drainage to prevent vacuum collapse and associated pipeline deformation. Its internal mechanism features a high-density, hydrodynamically optimized PVDF floater that reacts precisely to medium displacement and line pressures rated up to PN16 (16 bar).