Method and apparatus for cleaning pressure filters

Claim 1

A method of cleaning a pressure filter having a plurality of filtering elements each provided with a filter fabric through which a material to be filtered is passed in a filtration direction and which is subjected to depositing of a filter cake during the filtering process, comprising the steps of intermittently supplying a backwash cleaning medium to said filtering elements, in the direction opposite to said filtration under repeated pulsating shock-like, rhythmic pressure impulses for pushing the cleaning medium through the filter fabric of the filter elements in said opposite direction without causing any vibrations of the latter to thereby efficiently remove the cake from each cleaning element and thus clean the filter fabric without requiring disassembling of the pressure filter, the cleaning medium being supplied with a frequency of approximately 10-160 impulses per minute.

Claim 2

A method of cleaning a pressure filter having a plurality of filtering elements each provided with a filter fabric through which a material to be filtered is passed in a filtration direction and which is subjected to depositing of a filter cake during the filtering process, comprising the steps of intermittently supplying a backwash cleaning medium to said filtering elements, in the direction opposite to said filtration under repeated pulsating shock-like, rhythmic pressure impulses for pushing the cleaning medium through the filter fabric of the filter elements in said opposite direction without causing any vibrations of the latter to thereby efficiently remove the cake from each cleaning element and thus clean the filter fabric without requiring disassembling of the pressure filter, the cleaning medium being supplied with a frequency of approximately 10-160 impulses per minute.

Claim 6

A method of cleaning a pressure filter having a plurality of filtering elements each provided with a filter fabric through which a material to be filtered is passed in a filtration direction and which is subjected to depositing of a filter cake during the filtering process, comprising the steps of intermittently supplying a backwash cleaning medium to said filtering elements, in the direction opposite to said filtration under repeated pulsating shock-like, rhythmic pressure impulses for pushing the cleaning medium through the filter fabric of the filter elements in said opposite direction without causing any vibrations of the latter to thereby efficiently remove the cake from each cleaning element and thus clean the filter fabirc without requiring disassembling of the pressure filter, said impulses each having a magnitude of 2-10 at 0.5-to 3 bar.

Claim 7

A method of cleaning a pressure filter having a plurality of filtering elements each provided with a filter fabric through which a material to be filtered is passed in a filtration direction and which is subjected to depositing of a filter cake during the filtering process, comprising the steps of intermittently supplying a backwash cleaning medium to said filtering elements, in the direction opposite to said filtration under repeated pulsating shock-like, rhythmic pressure impulses for pushing the cleaning medium through the filter fabric of the filter elements in said opposite direction without causing any vibrations of the latter to thereby efficiently remove the cake from each cleaning element and thus clean the filter fabirc without requiring disassembling of the pressure filter, said impulses each having a magnitude of 2-10 at 0.5-to 3 bar.