Figure 4-2: S 4xx Dustbag Change Indicator
Depending on the dust quantity and type, and the hose attachment in use, the
indicator shows when the dustbag should be changed.
If flour or fine mineral dust is vacuumed, the indicator may show that the
dustbag should be changed even if it is not full.
As the bag is filled, its permeability is reduced and the negative pressure level
in the bag is reduced. At the same time the negative pressure in the dust
This increased negative pressure evacuates the dustbag change indicator
through its opening (Figure 4-2, Item 3) and removes air from the concertina
hose (Figure 4-2, Item 2). This then collapses and the visible indicator (Figure
4-2, Item 1) advances along its scale.
Figure 4-3: Suction Power Curve
The suction power is the product of the negative pressure developed and the
air throughput achieved divided by 10. The fan motor extracts air from the
S 2xx, S 3xx & S 4xx Canister Vacuums