The environmental protection has become essential. The water quality is a rare and expensive commodity and its production involves a problem more and more present with the industrial or urban slurries which need to be eliminated at a lower cost and if possible to be recovered.
The filter-press has an important place in numerous industries whenever slurries can be concentrated : it can be used either in process or at the end of treatment. In any case the filter-press enables an optimal separation of liquid and solid and the last technical developments which has made it 100 % automatic made it also 100 % topical.
The filter-presse is a machine used to filter under pressure the liquids loaded with solid matter in suspension. The filter-press is composed of 3 main parts : the frame, the filter part and the hydraulic power unit..
The filter-press design with two side beams enables to take out the plates easily from the top. This design is a big advantage compared to the design of machines whose plates are hanging under a top beam which involves a longer and harder handling.
The filtration on filter-press is made according to a discontinuous cycle :
Closing : the machine tightness and filtration pressure compensation is ensured by means of a hydraulic cylinder.
Filtration : the slurries are brought to a 6 to 30 bar pressure by a pump (centrifugal or membrane type) and fill out the chambers ; the liquid part called “filtrate” gets through the filter cloths which cover the plates and the solid particles remain in the plate chambers to form the cakes. The filtrate is then removed out through the plate channels or gutters. The cake is removed under the filter-press.
Opening : A detector enables to control the filtration end and gives the order to the cylinder to take the movable head back and therefore, to release the first cake.
Plate shifting : The end of movable head backward motion triggers the beginning of the plate shifting device which releases successively the cakes from their chambers.
The filter-press auxiliary equipment :
The washing bridge : it enables to increase the life duration of filter cloths and to ensure their efficiency. In order to carry out the washing operation, the washing bridge is locked to the plate shifting carriages; it is then positioned into the space between two plates. Two ramps fitted with sprayers are moved up and down between the plates while water is sent at the same time through sprayers at a 30, 80 or 100 bars to clean the filter cloths.
The automatic plate shifter : The filter-press usually requests the presence of an operator during the plate shifting phase to help the cake to fall when it remains stuck into the chamber. One of the last innovations on the CHOQUENET filter-press is the automatic plate shifter which enables to supersede the manual operation by an automatism, and this can be installed with any type of slurries to be filtered.
The protections by panels enable to protect the operators during the motion phases but also to protect them from projections in case of leakages between the plates.
The purpose of all our studies and researches in the filtration field with filter-press has been and remains that of keeping the rustic character of this machine, its robustness and its high reliability and therefore to ensure its continued existence. But we wanted also to make at the same time a modern machine by bringing all the possible improvements which will involve not only a complete automatism but also performances and results not equaled by other filtration means, i.e. a maximum dryness for a minimum cake volume, an energetic consumption a lot below the average and a maintenance cost almost negligible since the only consumables are the filter cloths. They have also took advantage of the technological progresses on their side and can now ensure several thousands of filtration cycles.