Filtering machine of filter plate type

A filter-plate-type filtration device that performs filtration inside a filtration chamber, the filtration chamber being formed by pressing a plurality of filter plates that are freely opened and closed against each other closely with a filter material sandwiched therebetween, the filter-plate-type filtration device comprising:

• a plurality of filter plates arranged to sandwich the filter material;
• a filtration chamber formed between the filter plates;
• a raw liquid introduction path configured to allow a raw liquid to be filtrated to be introduced to the filtration chamber;
• a pressure sealing unit configured to apply a sealing pressure to the filter material to prevent leakage of the raw liquid to be filtrated and a filtrate from inside of the filtration chamber to outside of the filtration chamber;
• and
• a control unit configured to automatically control the sealing pressure in response to fluctuations in a filtration chamber pressure,
• wherein the pressure sealing unit has a pressure seal portion main body formed of an elastic body, and
• wherein the pressure sealing unit is configured to apply the sealing pressure to the filter material by supplying a sealing fluid to elastically deform the pressure seal portion main body.

A filtration method performed by using a filter-plate-type filtration device including a plurality of filter plates arranged with a filter material sandwiched therebetween and a filtration chamber formed between the filter plates, the filtration method comprising:

• a pressure sealing step of applying a sealing pressure to the filter material by supplying a sealing fluid to the filter material;
• and
• a pressure control step of automatically controlling the sealing pressure such that leakage of a raw liquid to be filtrated and a filtrate from inside of the filtration chamber to outside of the filtration chamber is prevented,
• wherein in the pressure sealing step, the sealing pressure is supplied to the filter material by supplying a sealing fluid to elastically deform an elastic body.