Air diffuser and flushing method thereof

An air diffuser for use in a tank containing a mixed liquor, comprising:

• a diffuser tube immersed in a in the tank;
• a flushing pipe having an opening at its tip defining an outlet above the diffuser tube;
• and
• a flushing valve disposed in the flushing pipe,
• the diffuser tube having:
• a main pipe communicated at its basal end to an air supply source and communicated at its tip to the flushing pipe, the main pipe being located in a horizontal direction;
• and
• a plurality of branch pipes being communicated to the main pipes, each branch pipe having an opening at its tip defining a blowhole at a lower position of the main pipe characterized in that
• the flushing valve is opened while air is being supplied into the diffuser tube from the air supply source, the air supplied into the diffuser tube is evacuated through the flushing pipe, said mixed liquor inside the tank is refluxed into the diffuser tube through the blowholes following the evacuation of the air, and thus refluxed mixed liquor, together with the air forming a gas-liquid mixed phase flow, which runs through the flushing pipe and evacuates therefrom, wherein the mixed liquor is refluxed intermittently into the diffuser tube while the flushing valve is open and air is supplied into the diffuser tube from the air supply source, said intermittent refluxing of the mixed liquor caused by variations in pressure inside the diffuser tube, thereby causing pulsation in the diffuser tube.

An air diffuser for use in a tank containing a mixed liquor, comprising:

• a diffuser tube immersed in the tank;
• a flushing pipe having an opening at its tip defining an outlet above the diffuser tube;
• and
• a flushing valve disposed in the flushing pipe,
• the diffuser tube having:
• a main pipe communicated at its basal end to an air supply source and communicated at its tip to the flushing pipe the main pipe being located in a horizontal direction;
• and
• a plurality of branch pipes being communicated to the main pipe, each branch pipe having an opening at its tip at a lower position of the main pipe, and having at its upper part a plurality of blowholes each having an aperture smaller than the opening, characterized in that
• the flushing valve is opened while air is being supplied into the diffuser tube from the air supply source, the air supplied into the diffuser tube is evacuated through the flushing pipe, said mixed liquor inside the tank is refluxed into the diffuser tube through the blowholes following the evacuation of the air, and thus refluxed mixed liquor, together with the air forming a gas-liquid mixed phase flow, runs through the flushing pipe and evacuates therefrom, wherein the mixed liquor is refluxed intermittently into the diffuser tube while the flushing valve is open and air is supplied into the diffuser tube from the air supply source, said intermittent refluxing of the mixed liquor caused by variations in pressure inside the diffuser tube, thereby causing pulsation in the diffuser tube.

A method of flushing an air diffuser for use in a tank containing a mixed liquor in which, air is supplied into a diffuser tube from its basal end and dispersed from a plurality of blowholes provided at a lower part of a horizontal piping forming the diffuser tube, the diffuser tube being immersed in a tank, characterized in that

• said method comprises the steps of:
• opening a flushing valve while air is being supplied into the diffuser tube;
• evacuating the air supplied into the diffuser tube through the flushing pipe;
• refluxing the mixed liquor inside the tank into the diffuser tube through the blowholes following the evacuation of the air;
• causing the refluxed liquor to form, together with air, a gas-liquid mixed phase flow which runs through the flushing pipe and evacuates therefrom, and
• intermittently refluxing the mixed liquor into the diffuser tube while the flushing valve is open and air is being supplied into the diffuser tube, said intermittent refluxing of the mixed liquor caused by variations in pressure inside the diffuser tube, thereby causing pulsation in the diffuser tube.

An air diffuser for use in a tank containing a mixed liquor, comprising:

• a diffuser tube immersed in the tank;
• a flushing pipe having an opening at its tip defining an outlet above the diffuser tube;
• and
• a flushing valve disposed in the flushing pipe,
• the diffuser tube having:
• a main pipe communicated at its basal end to an air supply source and communicated at its tip to the flushing pipe, the main pipe being located in a horizontal direction;
• and
• a plurality of blowholes provided at a lower part of the main pipe,
• characterized in that
• the flushing valve is opened while maintaining a supply of air into the diffuser tube from the air supply source, in response thereto the air diffuser alternating between (a) a first state wherein mixed liquor flows into the diffuser tube via the plurality of blowholes to produce a gas-liquid mixed phase flow, and (b) a second state wherein mixed liquor does not flow into the diffuser tube via the plurality of blowholes, said alternating first and second states caused by pressure changes inside the diffuser tube, the alternating first and second states causing pulsing in the diffuser tube.