Air Release Valve Type 591 PP-H PN10 d16-d110

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The Georg Fischer PROGEF Standard Type 591 ventilating and bleed valve is an automatic industrial aeration and venting solution engineered for thermoplastic piping systems. Constructed from isotactic polypropylene homopolymer (β-PP-H), this valve is designed for socket fusion installation across metric dimensions from d16 up to d110 (nominal diameters DN10 to DN100) with a continuous pressure rating of PN10 (10 bar). It performs a critical double function in pressurized networks: automatically exhausting entrained air during pipeline filling and continuous operation to prevent water hammer and pressure drops, while instantly intaking atmospheric air during pipeline draining to prevent vacuum collapse.

The internal mechanism relies on a precisely calibrated PP-H float with a specific gravity of 0.91 g/cm³. As liquid fills the valve chamber, the float rises smoothly to compress against the elastomeric seat, establishing an airtight seal. When gas pockets accumulate or when system pressure drops below atmospheric levels during drainage, the float descends under gravity, clearing the venting orifice. Depending on media aggressiveness and chemical composition, sealing variants are available with durable EPDM or high-resistance FKM gaskets. A robust top cap fabricated from PP-GF (glass-fibre reinforced polypropylene) for sizes up to DN50 and POM (polyoxymethylene) for dimensions DN65 to DN100 shields the vent path against external debris and mechanical damage.

As an authorised Georg Fischer distributor, BigWeld provides genuine PROGEF Type 591 valves for rigorous industrial duties including chemical processing, industrial effluent treatment, water purification, and surface treatment facilities. The β-PP-H material provides outstanding resistance to non-oxidizing acids, alkalis, and elevated process temperatures, complying with long-term hydrostatic design requirements for a 25-year operational life with water at 20 degrees Celsius. The metric socket fusion connections ensure permanent, homogeneous joints with high structural integrity, while the compact body profile facilitates maintenance in confined plant configurations.