The filtration process by using
JVK membrane chamber
plates does differ remarkably from the normal filter press package
(chamber plates or plates and frames). The most important proces steps
are described below and explained by some graphics. Detailed description
and
further operating directions can be learned from the operating instructions.
- Filtration / feeding of filter
press
- Washing through feed port (gap washing)
- Pre-Squeezing and washing through corner
channels
- Squeezing of filter cake
- Blowing off the filter cake
1. Filtration / Feeding of Filter Press
During feeding the filter press the elastic membranes join in a most
uniform way, and with lowest tension to the core plate. Press feeding is
finished
immediately after filtration yield obtained the optimal working point "A".
Therefore - contrary to chamber plates - the filtration will be finished
prematurely
at lower pressure. It must be noted that the filter cake thickness after
squeezing is less than the chamber depth. Most optimal data for a suitable
design can be achieved by test filtration on the
JVK trial
filter press either at
JVK's plant or at site.
Residual
moisture after the filtration with membrane chamber |
 |
A = End of filtration with membrane chamber plate
B = End of filtration with chamber plates
C = Residual cake moisture after
the squeezing with membrane chamber plate
A`und C`are possible product
dependent operating values.
The optimal operating condition A can be determined after a few filtration
cycles. Cake compressibility, filtercloth, pump capacity etc. will influence
the process optimisation.
|
2. Washing through Feed Port (Gap Washing)
After finishing the filtration the cake layers can be washed through
the feed port. No squeezing and no overfilling is allowed in this case.
3. Pre-Squeezing and Washing through Corner Channels
During the following washing the cake is fixed in the chamber plate by
squeezing under low pressure and any cracks resp. gaps are
avoided.
Depending on channel arrangement and / or requested washing effects the
following versions are possible with JVK membrane chamber plates:
- Washing in one direction
- Washing in alternating directions
- Washing from top to bottom or from bottom to top (flooded)
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4. Squeezing of Filter Cake
Depending on structure and quality of the filter cake most of the liquid,
still remaining in the cake after filtration or washing get, displaced
by the membrane
pressure. The result is a very low residual moisture
content. The squeezing pressure is normally higher than the pre-squeezing
pressure.
5. Blowing-off the Filter Cake
With regard to most permeable cakes the blow-out by squeezing pressure
through corner ports can lead to an additional effective reduction of
cake moisture.