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Flanged Safety Relief Valves

Safety & Pressure Relief Valves

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LESER Series 441/442 ANSI High Performance Relief Valve

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LESER Series 441/442 ANSI High Performance Relief Valve

Inlet Sizes

DN25 - DN100 | 1" - 4"

Pressure Ratings

0.1 - 49 bar
ANSI 150# - ANSI 300#


SA 216 WCB, SA 351 CF8M


ASME VIII Div 1, CRN, PED, EN ISO 4126-1,TÜV SV 100 and AD 2000-Merkblatt A2

  • Applications

    Overpressure Protection for all General Industry Applications

    • Protection of chemical processes and equipment (e.g. distillation columns)
    • Heat exchangers
    • Low and medium pressure steam systems
    • Blowers and turbo compressors
  • Features

    The High Performance Product Group represents:

    ✓ High capacity related to the safety valve size
    ✓ High adaptability
    ✓ Excellent price / performance ratio

    LESER´s High Performance Safety Valves

    • Are designed to meet all industrial applications.
    • Open rapidly with an overpressure of 5 % to the full design lift.
    • Are used particularly for vapours and gases where the maximum mass flow has to be discharged rapidly.
    • Have a maximum blowdown of minus 10 % for steam/gas service and minus 20 % for liquid service.
    • Are one of the best selling spring loaded safety valve worldwide.
    • Are developed in a close cooperation with plant engineers and service specialists.
    • Serve for protection of processes and equipment.
    • Are approved by all important approval organisations worldwide which ensures the worldwide applicability e.g.:

    European Community: CE-marking acc. to Pressure
    Equipment Directive (PED) 97 / 23 / EC and EN ISO 4126-1

    USA: UV-stamp acc. to ASME Section VIII Division 1,
    National Board certified capacities

    Germany: VdTÜV approval acc. to PED, EN ISO 4126-1,
    TÜV SV 100 and AD 2000-Merkblatt A2
    Canada: Canadian Registration Number acc. to the
    requirements of particular provinces

    China: AQSIQ based on the approval acc. to ASME
    Section VIII Division 1 and AD 2000-Merkblatt A2

    Furthermore, all LESER High Performance safety valves
    are designed, marked, produced and approved acc. to the
    requirements of the following regulations (directives, codes,
    rules and standards).

    EN ISO 4126-7, EN 12266-1/-2, EN 1092 Part I and II flanging
    ASME PTC 25, ASME-Code Sec. II, ASME B 16.34 and ASME
    B16.5-flanging, API Std. 527, API RP 576
    AD 2000-Merkblatt A4, AD 2000-Merkblatt HP0, TRD 110,
    TRD 421, TRD 721

  • Options
    • O-ring-disc: CR “K” J21 | EPDM “D” J22 | FKM “L” J23 | FFKM “C” J20
    • Disc 1.4404 / 316L L44
    • Disc 1.4404 / 316L stellited J25
    • Detachable lifting aid J26
    • Stainless steel bellows
      – open bonnet (Type 442) J68
      – closed bonnet (Type 441) J78
    • Elastomer bellows J79
    • High temperature alloy spring X01
    • Stainless steel spring X04
    • Adaptor for lift indicator H4 J39
    • Lift indicator J93
    • Test gag
      – cap H2 J70
      – packed lever H4 J69
    • Heating jacket
      – Couplings G 3/8 H29 & G 3/4 H30
      – Flanges DN 15 H31 & DN 25 H32
    • Drain hole G 1/4 J18 & G 1/2 J19
    • Free of oil and grease J85
    • Materials
      – NACE N78
  • Datasheets