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Safety & Pressure Relief Valves


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LESER Type 459 Compact Performance Safety Relief Valve (Threaded)

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LESER Type 459 Compact Performance Safety Relief Valve (Threaded)

Inlet Connection

DN15 - DN40 | 1/2" - 1 1/2"
(Threaded BSP/NPT)

Pressure Rating

0.2 - 250 bar | 2.9 - 3626 psig


-273 to 450 °C | -459 to 842 °F
(acc. DIN EN)


PED/ DIN EN ISO 4126-1, AD 2000-Merkblatt A2, ASME Sec. VIII Div. 1, CRN, AQSIQ, EAC

  • Applications

    LESER – Compact Performance Safety Valves
    Offer ultimate protection against unallowable overpressures in all applications for steam, gases and liquids where smaller capacities are required.

    Typical applications for LESER Compact Performance Safety Valves are:

    • Air / gas compressors and pumps
    • Technical gases and CO2 plants
    • Cylinder filling stations
    • Chemical equipment and piping
    • Pressure vessels and piping systems containing gas, air, liquid or steam
    • LPG / LNG terminals, carriers etc.
    • Cryogenic systems and oxygen applications
    • Thermal relief
    • High pressure extraction plants
  • Features

    LESER´s Compact Performance Safety Valves cover a large variety of types, materials and options to fit any application:

    • Connection sizes from 3/8″ to 1 1/2″ and 5 orifices (D through F) provide high suitability to the application
    • Threaded connections, male and female, according to all international standards guarantee worldwide applicability
    • Flanged connections according ANSI, DIN and JIS guarantee a worldwide applicability
    • Inlet pressure ratings up to PN 700 / Class 2500 to fit all required design pressures
    • 2 standard based / inlet body materials, Chrome steel and stainless steel as well as 3 standard body materials, ductile iron, steel and stainless steel can be selected according to the application
    • All parts can be machined from bar materials to cover special material requirements such as Hastelloy®, Duplex, Super Duplex, Tantalum or Titanium within unrivalled lead time
    • Set pressures from 0.1 to 850 bar / 1.5 to 12328 psig make Compact Performance safety valves suitable for all industrial processes
    • Operating temperatures from -270 to 550 °C / -454 to 1022 °F (acc. to DIN EN) cover a wide range of applications
    • One design and spring (single trim) for steam, gas and liquid applications reduces the number of spare parts and ensures low cost maintenance management
    • Ringless design needs no trim adjustments for easy maintenance
    • One-piece spindle reduces friction which leads to high operation accuracy
    • Self-draining body design, avoids residues and reduces corrosion
  • Options

    LESER´s Compact Performance Safety Valves can be customized with a great variety of options, e. g.:

    • Special connections specified by the customer for optimised adaptation to the plant
    • Stellited or hardened metal sealing for longer product life
    • Soft seat solutions for superior tightness
    • Stainless steel bellows for back pressure compensation
    • Heating jackets for applications with high viscosity fluids
    • Base / inlet body, body, bonnet and all internal parts can be produced in special materials exactly to meet customer specification requirements
  • Datasheets