1. General Details


    • Constant airflow maintained with Δp across the filter of up to 17” of mercury (flow rate dependent)
    • Front panel mounted air flow indicator
    • Elapsed time meter and constant air flow rate permit accurate calculation of sample volume
    • Vacuum gauges for observing filter loading and pump performance
    • Flow rate indication on rotometer, CFM or LPM
    • Low noise level

    The Model HD-28A portable “K-Flow” bench type constant flow air sampler is designed for use on perimeter and off-site monitoring stations in environmental monitoring systems and in production and laboratory areas where collection of precise air samples is required. Its combination vacuum pump and constant air flow regulator permits the collection of an airborne particulate and iodine sample at a constant flow rate until the ΔP across the filter media exceeds the capability of the pump. The higher flow rate the lower the ΔP for constant flow control. The controlled flow rate is adjustable from 0.5 to 3.5 CFM through various diameter filters (such as fiberglass and membrane types) and charcoal or silver zeolite cartridges used for Iodine-131 collection.

    An internal air filtering system has been installed between the regulator valve and the pump to prevent particulates from reaching the self-adjusting carbon vanes and causing excess wear. A minimum of preventive maintenance assures a long performance life for the pump. A resettable elapsed time meter is mounted on the front instrument panel. By setting this timer to zero at the start of each sample period, an accurate sample volume may be readily calculated.

  2. Specifications

    Air Flow Rate: Adjustable from 0.5 to 3.5 CFM (15 -100 LPM).

    Air Flow Regulation: + 5% of set air flow rate up to maximum capability of pump.

    Dimensions/Weight: 18” Long x 11” Wide x 9” High (45.7 cm x 27.9 cm x 22.9 cm) 48 lbs (21.78 kg).

    Power Requirement: 115V, 60Hz, 4.6 Amps, 230V, 50Hz, 2.3 Amps. Three wire cord; six feet; 10 Amp rating. British and European available.

    Air Flow Indicator: Front panel mounted rotometer.

    Air Mover/Motor: Self-adjusting carbon vane type. Pump is designed for continuous operation at 26” Hg vacuum. 1/4 horsepower; thermal overload protection.

    Input Connection: 3/8” Female Quick Disconnect.

    Unit Cooling: 120 CFM extra high flow at maximum back pressures. All metal continuous duty fan.

    Re-settable Elapsed Time Meter: 99999 hours and 59 minutes, push button re-settable

  3. Sample Holders Available

    Model No.



    2” diameter filter, open face


    47 mm diameter filter, open face


    2” diameter filter/RADēCO cartridge, open face


    47 mm diameter filter/RADēCO cartridge, open face


    2” diameter filter/RADēCO cartridge


    47 mm diameter filter/RADēCO cartridge, in-line