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Cryogenic QCDC Couplings

  • The Alpha cryogenic QCDC quick connect/disconnect drybreak coupling is a high quality, reliable valve coupling that is used in the loading and unloading of cryogenic liquefied gases.

    Applications for the cryogenic QCDC couplings include small-scale LNG transfers to road rankers and also for LNG bunkering.

    This new family of products complements Alpha's existing range of couplings used extensively for the safe transfer of flammable, toxic, and corrosive products into tanker vehicles road, rail, barge or supply vessel to oil rig.

    For further information or to discuss your specific requirements in more detail, please don't hesitate to contact us.

  • Consistent
    The consistent drybreak facility reduces risk to operators and local environment from product spillage.

    Fully interlocked design
    A two stage operation of the coupling incorporates locking the male and female halves together before opening the flow valve handle. The coupling can not be disconnected while under flow condition.

    Fast connect/disconnect time allowing faster tanker turnaround or a reduction in loading points or both. Low pressure drop through the coupling allows faster filling times to be achieved.

    Complete ability
    Ability to close down valves under full flow and pressure conditions.

    High strength
    High strength and bending moment resistance when connected.

    Reliable operation
    The design of the coupling ensures reliable operation even in the most demanding operations.

    Rigorously tested
    Nitrogen gas testing for each individual coupling.

    Obtainable records
    Impeccable records retention to ensure correct spares are supplied when required.

    Spare parts
    Spare parts held in stock.

    Manufacturing quality
    Manufactured to the Highest Quality Control Standard - QA system ISO 9001 2008 approved.

  • Cyrogenic QCDC coupling applications:

    • Small-scale LNG road tanker loading and unloading
    • LNG bunkering
    • LNG ship to ship transfer.

    Typical cryogenic products handled include:

    • LNG, Liquid Nitrogen, Liquid Oxygen, Liquid Argon, Co2

    Other products handled include:

    • LPG, butane, propane, propylene
    • Chemicals: ammonia, methanol, aromatics, ethylene & propylene, VCM, alcohols & acids refrigerants forane
    • Speciality: hydraulic oils, inks, paints, solvents, locomotive fuelling, helicopter fuelling, aircraft de-icing fluids.
  • Sizes
    2", 3", 4", 6", 8" or metric equivalents.

    Main body construction
    Standard Material Stainless Steel 316.

    Threaded version 2" and 3" BSP or NPT.
    Flanged versions 2",3",4",6",8” to most standards including ANSI, DIN, ISO and JIS.


    Coupling designed for bi-directional flow.

    Temperature Range
    -196˚C to 100˚C.

  • Q. What is a QCDC coupling?

    A. QCDC stands for “quick connect disconnect”. The coupling can be a drybreak coupling usually comprises a female (hose end) fitting and a male (tanker fitting) that are connected/disconnected on a regular basis to form a liquid and pressure tight coupling. Drybreak couplings generally have a valve arrangement that shuts down the liquid flow prior to the disconnection of the male and female couplings.

    There are variations in QCDC couplings where the end user does not require a dry break capability and these couplings do not have internal valves. Alpha also manufacture this variation of coupling.

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