Pressure filter dewatering system and dewatering method

A pressure filter dewatering system, comprising:

• a pressure filter (1) comprising a plurality of filter plates (2) arranged side by side and capable of getting close to or away from each other, and filter cloth wrapping the filter plates (2), wherein a first chamber (3) used for accommodating a solid medium to form a filter cake may be formed between adjacent filter plates (2);
• a liquid inlet hole (4) for allowing suspension liquid to enter the first chamber (3) and a liquid outlet hole for allowing filtrate to flow out of the first chamber (3) are formed in each filter plate (2);
• each filter plate (2) comprises a core plate (5) and two membranes (6) respectively located on two sides of the core plate (5);
• a second chamber (7) is formed between the core plate (5) and each membrane (6);
• a first channel (8) and a second channel (9) which communicate with the second chambers (7) are arranged inside the core plate (5);
• an extrusion dewatering assembly used for physically extruding the filter cake in the first chamber (3), wherein the extrusion dewatering assembly comprises a hot water inlet pipe (10) communicating with the first channel (8) and a hot water outlet pipe (11) communicating with the second channel (9), and the hot water outlet pipe (11) is provided with a first valve (12);
• and
• a negative pressure dewatering assembly used for generating a negative pressure in the first chamber (3) and communicating with the liquid outlet hole.