Air supply duct for fan and combustion device including the same

An air supply duct for fan, which is used to guide air to a fan,

• comprising a duct main body portion in which an air passage extending in a predetermined x direction with one end side set as an air inlet port is formed inside, and an air supply port for supplying air travelling through the air passage to the fan is arranged, wherein
• a peripheral region of the air supply port of inside of the duct main body portion is surrounded by wall portions in a periphery except for a communication portion with the air passage, and is configured as a space portion capable of generating air column vibration and having a width in a y direction intersecting the x direction larger than a width of the air passage, wherein
• in the space portion, a width in the x direction is 15% to 35% of a width in the y direction.

An air supply duct for fan, which is used to guide air to a fan,

• comprising a duct main body portion in which an air passage extending in a predetermined x direction with one end side set as an air inlet port is formed inside, and an air supply port for supplying air travelling through the air passage to the fan is arranged, wherein
• a peripheral region of the air supply port of inside of the duct main body portion is surrounded by wall portions in a periphery except for a communication portion with the air passage, and is configured as a space portion capable of generating air column vibration and having a width in a y direction intersecting the x direction larger than a width of the air passage, wherein
• the space portion comprises a first region protruding to one side of the air passage and the air supply port in the y direction, and a second region protruding to an opposite side with respect to the first region, and widths of the first region and the second region in the y direction are different from each other.