Muffler for cooling fan noise reduction

A silencer for reducing noise of a heat dissipation fan, the silencer comprising:

• an outer tube;
• at least one inner tube inside the outer tube such that an annular space is formed between the at least one inner tube and the outer tube, the at least one inner tube including an inner cavity forming a ventilation channel;
• and
• a plurality of partition plates in the annular space and partitioning the annular space into a plurality of silencing chambers arranged along a conveying direction of airflow correspondingly to a plurality of silencing frequency bands, the at least one inner tube including a plurality of openings communicating the plurality of silencing chambers with the ventilation channel;
• wherein the plurality of silencing chambers includes a first silencing chamber having a silencing frequency band of 7500 Hz to 8500 Hz, a second silencing chamber having a silencing frequency band of 5500 Hz to 6500 Hz, a third silencing chamber having a silencing frequency band of 3000 Hz to 4000 Hz, and a fourth silencing chamber having a silencing frequency band of 1500 Hz to 2500 Hz, the first, second, third, and fourth silencing chambers are arranged from high silencing frequency to low silencing frequency along the conveying direction of the airflow;
• or
• wherein the plurality of silencing chambers includes a first silencing chamber having a silencing frequency band of 3000 Hz to 4000 Hz, a second silencing chamber having a silencing frequency band of 5500 Hz to 6500 Hz, and a third silencing chamber having a silencing frequency band of 7500 Hz to 8500 Hz.

A silencer for reducing noise of a heat dissipation fan, the silencer comprising:

• an outer tube;
• at least one inner tube inside the outer tube such that an annular space is formed between the at least one inner tube and the outer tube, the at least one inner tube including an inner cavity forming a ventilation channel;
• and
• a plurality of partition plates in the annular space and partitioning the annular space into a plurality of silencing chambers arranged along a conveying direction of airflow correspondingly to a plurality of silencing frequency bands, the at least one inner tube including a plurality of openings communicating the plurality of silencing chambers with the ventilation channel;
• wherein the plurality of silencing chambers includes a plurality of first silencing chambers, and the plurality of openings of the at least one inner tube includes multiple openings communicating with each said first silencing chamber that are arranged at intervals along a circumferential direction of the corresponding first silencing chamber;
• and
• wherein:
• the plurality of first silencing chambers include at least one first-first silencing chamber having a silencing frequency band of 7500 Hz to 8500 Hz, at least one second-first silencing chamber having a silencing frequency band of 5500 Hz to 6500 Hz, at least one third-first silencing chamber having a silencing frequency band of 3000 Hz to 4000 Hz, and at least one fourth-first silencing chamber having a silencing frequency band of 1500 Hz to 2500 Hz;
• or
• the plurality of first silencing chambers include at least one fifth-first silencing chamber having a silencing frequency band of 3000 Hz to 4000 Hz, at least one sixth-first silencing chamber having a silencing frequency band of 5500 Hz to 6500 Hz, and at least one seventh-first silencing chamber having a silencing frequency band of 7500 Hz to 8500 Hz.

A silencer for reducing noise of a heat dissipation fan, the silencer comprising:

• an outer tube;
• at least one inner tube inside the outer tube such that an annular space is formed between the at least one inner tube and the outer tube, the at least one inner tube including an inner cavity forming a ventilation channel;
• and
• a plurality of partition plates in the annular space and partitioning the annular space into a plurality of silencing chambers arranged along a conveying direction of airflow correspondingly to a plurality of silencing frequency bands, the at least one inner tube including a plurality of openings communicating the plurality of silencing chambers with the ventilation channel;
• wherein the plurality of silencing chambers includes:
• at least one first-second silencing chamber having a silencing frequency band of 8700 Hz to 9200 Hz, and a single annular opening of the plurality of openings of the at least one inner tube is arranged and extending along a circumferential direction of the at least one first-second silencing chamber;
• at least one first-first silencing chamber having a silencing frequency band of 3000 Hz to 4000 Hz, and multiple openings of the plurality of openings of the at least one inner tube are arranged at intervals along a circumferential direction of the at least one first-first silencing chamber;
• at least one second-first silencing chamber having a silencing frequency band of 5500 Hz to 6500 Hz, and multiple openings of the plurality of openings of the at least one inner tube are arranged at intervals along a circumferential direction of the at least one second-first silencing chamber;
• and
• at least one second-second silencing chamber having a silencing frequency band of 8000 Hz to 8500 Hz, and a single annular opening of the plurality of openings of the at least one inner tube is arranged and extending along a circumferential direction of the at least one second-second silencing chamber;
• or wherein the plurality of silencing chambers includes:
• at least one third-second silencing chamber having a silencing frequency band of 8000 Hz to 8500 Hz, and a single annular opening of the plurality of openings of the at least one inner tube is arranged and extending along a circumferential direction of the at least one third-second silencing chamber;
• at least one third-first silencing chamber having a silencing frequency band of 5500 Hz to 6500 Hz, and multiple openings of the plurality of openings of the at least one inner tube are arranged at intervals along a circumferential direction of the at least one third-first silencing chamber;
• at least one fourth-second silencing chamber having a silencing frequency band of 8700 Hz to 9200 Hz, and a single annular opening of the plurality of openings of the at least one inner tube is arranged and extending along a circumferential direction of the at least one fourth-second silencing chamber;
• and
• at least one fourth-first silencing chamber having a silencing frequency band of 3000 Hz to 4000 Hz, and multiple openings of the plurality of openings of the at least one inner tube are arranged at intervals along a circumferential direction of the at least one fourth-first silencing chamber.