The powdered polymer falls into the wetting cone, where it is uniformly
wetted with a partial flow from the preparation water. This ensures
clumping of the feed chemical does not occur.
The main flow of the preparation water produces, by way of a mixing
device, a slight vacuum at the outlet of the cone. Consequently, the wetted
powder is sucked out and then travels with the preparation water into
chamber 1.
The switching on of the powder feeder is controlled to occur at a time
delay after the solenoid valve activation. Consequently at the start of the
preparation process, no powder deposits can occur in the flush fitting.
There is always a water flow for a few seconds before the powder feeder
starts. At the end of the preparation process, the reverse procedure is fol‐
lowed. The system switches off immediately once the upper level is
reached. However, the water continues to run for a few seconds after this.
A0431
Fig. 6: Water fitting with Y-flush inlet
1. Shut-off valve
2. Pressure reducer
3. Solenoid valve
4. Flow meter
5. Regulating valve
6. Y-flush inlet
Design and function
21
