# US 12,763,055 B2 · Muffler for cooling fan noise reduction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,763,055 B2 - Document ID: US12763055B2 - Status: Granted - Kind: B2 - Application number: 18/924,998 - Filed: 2024-10-23 - Published: 2025-04-24 - Granted: 2026-10-13 - Earliest claimed: 2023-10-26 - Assignees: Laird Technologies (Shenzhen) Ltd. - Applicants: Laird Technologies (Shenzhen) Ltd. - Inventors: Shangyu Chen; Xu Han; Qingsheng Gao; Yifan Xu; Xiaohu Xu; Donglai Xu; Guiyun Chen; Youhong Li - Web page: https://patentgrep.com/patent/US12763055B2 ## CPC - G10K 11/002: {Devices for damping, suppressing, obstructing or conducting sound in acoustic devices (G10K1/06 - G10K1/10 take precedence; for electro-mechanical transducers for communication H04R3/002)} - H05K 7/20727: {within server blades for removing heat from heat source} - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS ## Abstract A silencer or muffler for reducing noise of a heat dissipation or cooling fan includes an outer tube and at least one inner tube inside the outer tube. An annular space is formed between the inner and outer tubes. An inner cavity of the inner tube forms a ventilation channel. Partition plates are installed in the annular space that partition the annular space into silencing chambers arranged along a conveying direction of airflow. The inner tube includes openings communicating the silencing chambers with the ventilation channel. The silencing chambers are disposed correspondingly to silencing frequency bands. A limited installation space in an electronic device chassis can be used to achieve sound absorption and noise reduction for a heat dissipation fan in the silencing frequency bands. ## Claims ### Claim 1 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: an air outlet end of the ventilation channel is communicated with an air inlet of the heat dissipation fan of a fan structure through a rear flow-guiding channel; the rear flow-guiding channel is tapered outwards along the conveying direction of the airflow; the air inlet end of the ventilation channel is communicated with a front flow-guiding channel; the front flow-guiding channel is tapered inwards along the conveying direction of the airflow; a cellular mesh structure is at an inlet of the front flow-guiding channel; and the rear flow-guiding channel is sealingly connected with the air inlet of the heat dissipation fan through a sealing structure. ### Claim 2 (depends on 1) The silencer of claim 1, wherein: the higher the silencing frequency band corresponding to the silencing chamber is, the larger an area of the opening correspondingly communicated is and/or the smaller a volume of the silencing chamber is; and the lower the silencing frequency band corresponding to the silencing chamber is, the lower the area of the opening correspondingly communicated is and/or the larger the volume of the silencing chamber is. ### Claim 3 (depends on 1) The silencer of claim 1, 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; or 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. ### Claim 4 (depends on 1) The silencer of claim 1, 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. ### Claim 5 (depends on 1) The silencer of claim 1, wherein the sealing structure comprises a mounting plate and a sealing ring. ### Claim 6 (depends on 1) The silencer of claim 1, 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. ### Claim 7 (depends on 1) The silencer of claim 1, wherein the plurality of silencing chambers have silencing frequencies and are arranged from high silencing frequency to low silencing frequency along the conveying direction of the airflow. ### Claim 8 (depends on 1) A server comprising a heat dissipation fan and the silencer of claim 1, wherein the silencer is operable for sound absorption and noise reduction of fan noise generated by the heat dissipation fan in the server. ### Claim 9 (depends on 1) The silencer of claim 1, wherein the sealing structure comprises a mounting plate and a sealant. ### Claim 10 (depends on 1) The silencer of claim 1, wherein the sealing structure comprises a mounting plate and a sealing member. ### Claim 11 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. ### Claim 12 (depends on 11) The silencer of claim 11, wherein: an air outlet end of the ventilation channel is communicated with an air inlet of the heat dissipation fan of a fan structure through a rear flow-guiding channel; the rear flow-guiding channel is tapered outwards along the conveying direction of the airflow; the air inlet end of the ventilation channel is communicated with a front flow-guiding channel; and the front flow-guiding channel is tapered inwards along the conveying direction of the airflow. ### Claim 13 (depends on 12) The silencer of claim 12, wherein: a cellular mesh structure is at an inlet of the front flow-guiding channel; and the rear flow-guiding channel is sealingly connected with the air inlet of the heat dissipation fan through a sealing structure. ### Claim 14 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. ### Claim 15 (depends on 14) The silencer of claim 14, wherein: the plurality of silencing chambers comprises at least one second silencing chamber; and the plurality of openings of the at least one inner tube includes a single opening communicating with the at least one second silencing chamber that is an annular opening arranged and extending along a circumferential direction of the corresponding second silencing chamber. ### Claim 16 (depends on 15) The silencer of claim 15, wherein: the silencer includes only one said second silencing chamber; or the at least one silencing chamber comprises a plurality of second silencing chambers. ### Claim 17 (depends on 15) The silencer of claim 15, wherein the at least one silencing chamber comprises two second silencing chambers such that one second silencing chamber is disposed near an air inlet end of the ventilation channel and another second silencing chamber is disposed near an air outlet end of the ventilation channel. ### Claim 18 (depends on 15) The silencer of claim 15, wherein the silencer includes a sound absorbing foam along an inner wall surface of the outer tube in the at least one second silencing chamber, the sound absorbing foam having a thickness less than a radial width of the annular space. ### Claim 19 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.