DIGITEL Low Volume Sampler maintenance

Digitel dust samplers requires minimum maintenance. However, depending on the degree of air pollution and climatic load upon installation site, inspection of the sampler associated with cleaning is necessary.

In particular, the following activities shall be performed:

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Cleaning:
Low Volume Samplers must be cleaned on regular basis. Cleaning intervals strongly depend on particulars of installation site and they have to be determined by the operator. They may range from one month up to a year.
During cleaning, the instrument should be off power.
To clean the instrument, a dry cloth should be used. At heavy contamination, the cloth should be wetted with a commercial window cleaning agent. Make sure that the instrument is dried up before putting under operation, again.
Avoid using solving and scrubbing cleaning products!
The flow meter glass tube has to be visually inspected. In case of broken filter or negligent sampler operation without filter inserted, contamination can also occur. In case of any doubt, the tube has to be removed and cleaned.

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Tightness test. Checking of volume-flow calibration
At the start up, displayed blower load level, converter frequency, flow and filter type will be recorded. Sudden insufficient blower capacity under the same conditions, is caused by leakage in the air-sample path (after the filter).
Another very simple option for testing the sampler tightness consists in closing the sampler at the inlet muffle with the inlet tube removed or, as the case may be, by inserting an air-impenetrable cardboard instead of the filter paper to the filter holder and switching the blower on. In both cases, the flow meter floater must not be lifted from its resting position at the bottom of the measurement tube. Hereby the blower must be run up to its maximum capacity in order to reach the overload condition.
Installing a second flow meter at the sampler inlet and checking the two flows volume match is a way of leak check. The second flow meter acts as a "transfer standard". New filter will be installed when prodeeding to calibration / leak check. A flow deviation from the last calibration may be caused by leak in the system..