Method for operating a filter press and a filter press

A filter press, comprising:

• a filter chamber configured for receiving filter material to be filtered;
• a flexible filter medium having at least two sides, said filter medium being positioned within said filter chamber, and configured for receiving filter material to be filtered between the at least two sides, so as to separate filtrate from solids of said filter material by filtration;
• a feed arrangement comprising:
• a filter material supply, and
• a filter material flow route,
• the feed arrangement being configured to feed filter material at a feed pressure from a filter material supply to the filter chamber to be filtered therein by the filter medium, thereby forming a filter cake within the filter chamber, between the at least two sides of the filter medium;
• a drainage arrangement configured to receive filtrate from the filter chamber through the filter medium;
• a discharge arrangement for discharging the filter cake formed within the filter chamber;
• a compression arrangement having:
• a compression gas flow route for enabling fluid communication for a compression gas form a compression gas supply directly to a side of the filter medium, exterior to the filter chamber, and
• a compression gas supply for providing, via the compression gas flow route, compression gas to directly a side of the filter medium exterior to the filter chamber,
• a compression gas control means for selectively enabling or disabling gas flow from the compression gas supply via the compression gas flow route,
• wherein the compression arrangement is configured to provide compression gas at a compression pressure exceeding a prevailing pressure within the filter chamber, directly on a side of the filter medium exterior to the filter chamber, so as to exert said compression pressure directly on said side of the filter medium, thereby causing the filter medium to yield against the filter cake,
• wherein feed arrangement being further configured to maintain said feed pressure within the filter chamber at least until the compression pressure is achieved on the side of the filter medium exterior to the filter chamber
• wherein the filter chamber is horizontal, and formed by an upper filter plate and a lower filter plate one above the other, said filter plates being retractable away from each other for filter cake discharge,
• the filter medium comprising:
• an upper side fixed to the upper filter plate and
• a lower side movable with respect to the lower filter plate for filter cake discharge.