A High Volume Sampler (HVS) for autonomous, continuous measurements. The DHA-80 is a system for sampling dust and aerosol particles for later assessment and analysis.

The sampler operation range in standard execution is from 100 – 1000 l/min (6 – 60 m3/h).

The system is usually called ‘High Volume Sampler’. Various models of samplers are available from different applications. Generally, they differ by the number of filters processed and by the type of logging failure indication and status messages as well as by the type of remote control via various interface protocols.

Air-borne dust particles in the sampled air are separated on to Ø 150 mm filters. The flown filter diameter is 140 mm. Sequent gravimetric and analytical analysis could be conducted depending upon the pollutants of interest. Filter material and structure selection (deep filters, porous filters, glass fibres, silica fibres, pulp, Teflon, porosity…) will depend on the analysis purpose. The filter conditioning is important in order to achieve reproducible results. DHA-80 has a container of 15 filters stretched in filter holders. They are changed automatically to the flow position at the pre-set time.

How it works

The air is sampled through a PM₁₀/ PM₂.₅/ PM₁ inlet, using a sampling tube, vertically from the top to the bottom through the filter placed in the flow chamber. The upper part of the flow chamber works like a diffuser with a regular cross section and ensures uniform loading of the exposed circular filter. Due to the relatively large filter diameter, the face velocity of the sampled air through the filter is only 0,5m/s (at a flow rate of 500l/min). The pressure drop across the filter is limited to 130 mbar, so that a rupture of damp or extremely loaded filters is prevented. The DHA-80 changes the filters automatically. Behind the filter, the transported air quantity is measured by a flow meter with a float. Its double photosensor optically captures the float position.

With help of the control electronics, the capacity of the blower is adapted to the rpm control, so that the air quantity keeps the set-point value. Air pressure and temperature are measured upstream the flow metre and continuously averaged by the control. A realtime protocol states sampling volumes yielding from the sampling time and controlled volume flow as the core information. The air is released from the instrument with reduced noise through the noise baffle.

Servicing

Servicing information