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    Sherwood re-invents the Weir

    for improved precision of results in
    Flame Photometer—Dilutor systems.

    Sherwood Scientific’s Model 805 continuous flow Dilutor is used in laboratories to give consistent
    sample dilution prior to sample aspiration into one of the company’s range of Flame Photometers.
    Used together with one of Sherwood’s dual channel instruments, the Models 420, 425 or 420Cs; the
    Dilutor can also add in the internal reference (Lithium or Caesium) to enable enhanced precision.
    Once diluted, the sample/reference mix is fed by the Dilutor to a Weir Cup, from which the Flame
    Photometer aspirates a portion for analysis in the flame.

    Old Weir v's New Weir

    Two mounting options are available for the Open Weir Cup Assembly: a Mounting Boss fitted to the
    sample presentation area of new build 400 series Flame Photometers and a Support Arm for
    retrofits to older instruments.

    Open Weir Cup Assembly Support Arm
    The Holder Assembly, together with the Mounting Boss or Retrofit Support Arm, ensure correct
    positioning and height of the Open Weir Cup.  An integrated, manually adjustable, capillary ensures
    sample aspiration from the optimal place; just within the meniscus of the diluted sample stream.

    The Mounting Boss, 800 02 006, should only be ordered separately as a spare for a damaged one.
    They are now supplied fitted to the base moulding of all new 400 series Flame Photometers; i.e.
    M410, M420, M420Cs & M425. The Mounting Boss is not intended for Operators or Distributors to
    install to older instruments.

    The Open Weir Cup Holder Assembly, 800 15 006, will be supplied as standard with new Dilutors,
    together with the Open Weir Cup Assembly, 800 09 010. With new build Dilutors, these two
    components will be supplied already combined as one assembly: Holder Assembly, Weir (Open)
    Inc., Weir Cup, 800 15 000.

    Customers who order a new Dilutor to run with an old Flame Photometer* i.e. without a Mounting
    Boss, will need to order a Support Arm (Upper), 800 15 002. The Support Arm (Upper) is fitted to
    the Flame Photometer, then the Holder Assembly, Weir (Open) Inc., Weir Cup, 800 15 000,
    supplied with the dilutor is fixed to the Support Arm (Upper).

    To upgrade to the new Open Weir Cup, customers with an older Flame Photometer* and Dilutor,
    need to order the Holder Assembly Retrofit Weir Cup (open) 800 15 001 which includes 800 15 000
    and 800 15 002.

    *Older Flame Photometers with the small plastic Constant Head & Drain; SN#20586 – #28015, will
    require the Constant Head & Drain, Large – Replacement Kit 410 11 001.

    Part Number 800 15 007 provides that kit 410 11 001 together with Holder Assembly Retrofit Weir
    Cup (Open) 800 15 001.