Visual examinations necessary to minimise leakage are as follows.
| (i) |
Grit pots at the bottom of cyclones must be tight fitting and with no cracks or cuts. Cable ties or clamps may be necessary in some instances. |
| (ii) |
Check that rubber 'O'-rings, where fitted, are in good order. |
| (iii) |
Check each segment of the filter cassette for cracks. The various segments must be firmly pressed together to ensure that the filter media and support pad are well nipped. Wrap the joints with a good quality insulation tape or shrink seal. |
| (iv) |
Cyclones must be critically examined for loose screws, missing gaskets, perished or oversized rubber 'O'-rings, broken or cracked parts etc, |
| (v) |
Good quality transparent tubing, in good condition (no cracks or weak areas), must be used. Ali connections must be fitted with cassette adaptors, cable ties or clamps. Tube connections must be made over outlet parts. Insert-type connections must be avoided, |
| (i) |
Check that the rubber '0'-rings are in good order where fitted. |
| (ii) |
Fit the pre-weighed filter paper precisely on top of a new support pad (a metal support grid is not recommended) inside the filter cassette. Ensure that the filter media faces the intake airside of the assembly. |
| (iii) |
For a proper seal check that the filter cassette rides on the small rubber 'O'-ring inside the cyclone before assembly. Secure the threaded plastic ring firmly. |
| (i) |
All instruments must be cleaned after use with a damp cloth, which has been submerged in a mild solution of detergent and water. |
| (ii) |
Cyclones and plastic cassettes must be washed in a mild solution of detergent and water. Rinsing with water should be followed up with a final rinse in methyl alcohol after which they should be allowed to dry. |
| (iii) |
The use of an ultra-sonic bath is also recommended for the cleaning of cyclones and cassettes. |
| (iv) |
Due to the possible contamination of filters, Vaseline or silicone grease is not recommended for sealing purposes. |
| (v) |
A good seal is indicated when the edge around a used filter paper, where the two interlocking segments of the cassette make contact with the filter paper, is free of particulate matter. |
| (vi) |
The removal of the cyclone body from the cassette must be done slowly and with great care so as not to dislodge any collected particulate matter from the fiIter. |
NOTE: Filter holders should be removed from the cyclone at the end of sampling for transport to the weighing facility with the dust deposit side facing upwards. Unnecessary movement or handling before transportation is undesirable.
Gas Regulator Levies Act, 2002
