The medium to be filtered enters the filter through the inlet nozzle (below intermediate ring), flows through the slot type filter elements outside to inside
before the filtered medium leaves the filter through the outlet nozzle. Thus, all dirt particles whose diameter is larger than the die gap of the filter elements are kept on the outside of the filter
element.
The filter insert is cleaned by rotating the filter element whereby the fixed scraper removes the dirt from the surface of the filter element. The dirt of a density higher than that
of the liquid to be filtered falls into the cone bottom owing to gravity. It is to be drained from time to time.
Increasing contamination of the filter element causes a reduction of the free
filter area of the slot type element. That leads to an increasing pressure drop at the filter element.
Manual operation:
At the maximum allowable pressure difference the gear
motor is activated for 2 – 3 rotations or, if applicable, turned by means of the crank handle. The manual drain valve is to be opened for a short time.
Batch operation:
In
case of batch operation the filter can be cleaned throughout the entire filtration process by permanent rotation of the filter insert. Its advantage is a constantly low pressure difference. The filter is to
be drained after batch operation.
Fully automatic equipment:
When the manually adjustable pressure difference (max. 1 bar) between dirt and clean side of the filter is
reached, a circuit is closed over the pressure difference contact gauge. This is the signal for the control to initiate self-cleaning by mechanical scraping the dirt from the filter surface. The dirt
draining is performed after a certain number of cleanings or after an adjusted time respectively.
Extra equipment dirt drain sluice:
To drain the dirt automatically during
filtration, the filter can be equipped with a dirt drain sluice. Herewith a limited dirt and liquid rate is drained out of the filter. A pressure drop of the system on opening of filter draining is
being avoided.
Only a sluice housing and an additional shut-off valve is needed. In special cases a flushing connection at the sluice housing could be useful.
