Four-way valve for backflush filter system

A four-way valve for a backflush filter system, the backflush filter system (1) mainly being used for removing impurities from liquid or gas, the four-way valve comprising a valve body (3) and a rotating valve core (2) having a valve rod at one end of a central shaft, wherein a valve core port IV (16) is arranged at the other end of the central shaft of the valve core (2);

• three ports are arranged in the radial direction of the valve core (2):
• a valve core port I (13), a valve core port II (14) and a valve core port III (15);
• the valve core port IV (16) is communicated with the valve core port I (13) to form a flow channel;
• the valve core port II (14) is communicated with the valve core port III (15) to form a flow channel;
• the two flow channels are not communicated with each other;
• the valve body (3) encasing the valve core (2) also has four ports;
• three radial ports are respectively a valve body port I (9), a valve body port II (10) and a valve body port III (11), and the other port is an axial valve body port IV (12);
• the valve body port I (9) and the valve body port III (11) of the valve body (3) are respectively connected with two filter units I (4) and II (7);
• the other valve body port II (10) and the valve body port IV (12) are respectively connected with a sewage drainage port or a water inlet;
• the valve core port IV (16) is communicated with the valve body port IV (12);
• when the valve body port IV (12) is used for connecting a water inlet, a flow channel formed by communicating the valve core port IV (16) with the valve core port I (13) is a water inlet channel, and a flow channel formed by communicating the valve core port II (14) with the valve core port III (15) is a sewage drainage channel;
• at this moment, at least one of the valve body port I (9), the valve body port III (11) and the valve core port I (13) is larger than the smaller of the valve core port IV (16) and A1;
• A1 is the minimum cross-sectional area of the flow channel before the valve core port IV(16);
• when the valve body port II (10) is used for connecting the water inlet, a flow channel formed by communicating the valve core port II (14) with the valve core port III (15) is a water inlet channel, and a flow channel formed by communicating the valve core port IV (16) with the valve core port I (13) is a sewage drainage channel;
• at this moment, at least two of the valve body port I (9), the valve body port II (10), the valve body port III (11), the valve core port II (14) and the valve core port III (15) are larger than the smaller of the valve the valve body port 11 (10) and A2;
• and A2 is the minimum cross-sectional area of the flow channel before the valve body port II (10).