Abstract: An air supply duct for fan is used to guide air to an air intake port of a fan, and includes 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 air intake port of the fan is arranged. A peripheral region of the air supply port of the inside of the duct main body portion is surrounded by wall portions in the periphery except for a communication portion with the air passage, and is configured as a space portion for generating air column vibration and having a width in a y direction intersecting the x direction larger than a width of the air passage. A combustion device including the air supply duct is provided.

Abstract: Provided is a water heater including a burner that receives a supply of combustion air from a fan, a heat exchanger having a heat transfer tube, and a combustion chamber case in which a combustion chamber of the burner is formed in the interior thereof and which is to be capable of guiding combustion gas generated by the burner to the heat exchanger. The water heater further includes a unit case that surrounds the combustion chamber case, and a region on the outside of the combustion chamber case within the unit case serves as an air pressure chamber having a higher pressure than the combustion chamber. Thus, combustion gas leakage to the outside can be prevented or suppressed appropriately by means of a simple configuration.

Abstract: An air supply duct for fan is used to guide air to an air intake port of a fan, and includes 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 air intake port of the fan is arranged. A peripheral region of the air supply port of the inside of the duct main body portion is surrounded by wall portions in the periphery except for a communication portion with the air passage, and is configured as a space portion for generating air column vibration and having a width in a y direction intersecting the x direction larger than a width of the air passage. A combustion device including the air supply duct is provided.

Abstract: Provided is a water heater including a burner that receives a supply of combustion air from a fan, a heat exchanger having a heat transfer tube, and a combustion chamber case in which a combustion chamber of the burner is formed in the interior thereof and which is to be capable of guiding combustion gas generated by the burner to the heat exchanger. The water heater further includes a unit case that surrounds the combustion chamber case, and a region on the outside of the combustion chamber case within the unit case serves as an air pressure chamber having a higher pressure than the combustion chamber. Thus, combustion gas leakage to the outside can be prevented or suppressed appropriately by means of a simple configuration.

Abstract: A fan includes: an impeller including a main plate having a first plane, a plurality of first blades each formed the first plane, and a shroud formed integrally with the plurality of first blades; a fan case; a drive source; and a rotation shaft. The first blades each include a linearly protruding region that is linearly increased in height from an outer circumferential side to an inner circumferential side, and a curvedly protruding region that is curvedly increased in height from the outer circumferential side to the inner circumferential side, the height extending in a direction in which each first blade protrudes. The linearly protruding region is welded to the main plate. Accordingly, a highly durable fan can be implemented that allows sufficient durability to be maintained even under a high temperature environment or an acid environment.

Abstract: A fan includes: an impeller including a main plate having a first plane, a plurality of first blades each formed the first plane, and a shroud formed integrally with the plurality of first blades; a fan case; a drive source; and a rotation shaft. The first blades each include a linearly protruding region that is linearly increased in height from an outer circumferential side to an inner circumferential side, and a curvedly protruding region that is curvedly increased in height from the outer circumferential side to the inner circumferential side, the height extending in a direction in which each first blade protrudes. The linearly protruding region is welded to the main plate. Accordingly, a highly durable fan can be implemented that allows sufficient durability to be maintained even under a high temperature environment or an acid environment.

Abstract: A water heater capable of cooling a fan by inflow of air while suppressing backflow of combustion gas is provided. A fan includes: a fan case having a back surface wall; an impeller having a first blade and a second blade and housed in the fan case; a drive source rotating the impeller; and a rotation shaft coupling the impeller and the drive source through a through hole provided in the back surface wall. A gap through which air outside the fan case is suctioned into the fan case is provided between the rotation shaft and the back surface wall. The second blade faces the back surface wall without another member interposed therebetween throughout a range from an inner circumferential side to an outer circumferential side of the second plane.

Abstract: A fan includes: an impeller including a main plate having a first plane, a plurality of first blades each formed the first plane, and a shroud formed integrally with the plurality of first blades; a fan case; a drive source; and a rotation shaft. The first blades each include a linearly protruding region that is linearly increased in height from an outer circumferential side to an inner circumferential side, and a curvedly protruding region that is curvedly increased in height from the outer circumferential side to the inner circumferential side, the height extending in a direction in which each first blade protrudes. The linearly protruding region is welded to the main plate. Accordingly, a highly durable fan can be implemented that allows sufficient durability to be maintained even under a high temperature environment or an acid environment.

Abstract: A fan includes: an impeller including a main plate having a first plane, a plurality of first blades each formed the first plane, and a shroud formed integrally with the plurality of first blades; a fan case; a drive source; and a rotation shaft. The first blades each include a linearly protruding region that is linearly increased in height from an outer circumferential side to an inner circumferential side, and a curvedly protruding region that is curvedly increased in height from the outer circumferential side to the inner circumferential side, the height extending in a direction in which each first blade protrudes. The linearly protruding region is welded to the main plate. Accordingly, a highly durable fan can be implemented that allows sufficient durability to be maintained even under a high temperature environment or an acid environment.

Abstract: A fan includes: an impeller including a main plate having a first plane, a plurality of first blades each formed the first plane, and a shroud formed integrally with the plurality of first blades; a fan case; a drive source; and a rotation shaft. The first blades each include a linearly protruding region that is linearly increased in height from an outer circumferential side to an inner circumferential side, and a curvedly protruding region that is curvedly increased in height from the outer circumferential side to the inner circumferential side, the height extending in a direction in which each first blade protrudes. The linearly protruding region is welded to the main plate. Accordingly, a highly durable fan can be implemented that allows sufficient durability to be maintained even under a high temperature environment or an acid environment.

Abstract: A fan assembly includes a fan and an emission connection portion. The fan includes a fan case having a first internal space, an impeller, and a rotation shaft. The emission connection portion includes a connection portion case having a second internal space and provided with an emission port for emitting gas sent from the fan to the outside of the fan assembly through the second internal space. In a plan view from a direction of axis of the rotation shaft, a tongue portion extending from one end toward the other end is located at a boundary between the first internal space and the second internal space, and the tongue portion is provided to extend to a position at least reaching a straight line connecting a center point of the emission port and a center of rotation of the rotation shaft to each other, from one end toward the other end.

Abstract: A water heater is provided that can suppress backflow (entry) of drainage water into a fan from downstream of the fan in a path of a flow of combustion gas. The fan includes a fan case, an impeller housed within the fan case, a drive source attached to the fan case so as to drive the impeller, and a rotation shaft connecting the impeller and the drive source. An exhaust connection portion has a connection portion case and is provided with an exhaust port for emitting combustion gas delivered from the fan to outside of the water heater. The exhaust connection portion also has a drainage water discharge portion for discharging drainage water accumulated downstream of the fan in the path of the flow of combustion gas.

Abstract: A water heater of a latent heat recovery type includes: a combustion apparatus including a burner having a plurality of burner port portions and generating combustion gas from openings at ends of the plurality of burner port portions; a heat exchanger heating water that flows through inside by heat exchange with combustion gas generated in the combustion apparatus; and a fan suctioning the combustion gas that has passed through the heat exchanger and emitting combustion gas to outside of the water heater. The fan includes a fan case, an impeller housed within the fan case, and a drive source connected to the impeller. At least a part of an upper surface of a bottom wall of the fan case is inclined with respect to a reference plane including the openings of the plurality of burner port portions.

Abstract: A fan assembly includes a fan and an emission connection portion. The fan includes a fan case having a first internal space, an impeller, and a rotation shaft. The emission connection portion includes a connection portion case having a second internal space and provided with an emission port for emitting gas sent from the fan to the outside of the fan assembly through the second internal space. In a plan view from a direction of axis of the rotation shaft, a tongue portion extending from one end toward the other end is located at a boundary between the first internal space and the second internal space, and the tongue portion is provided to extend to a position at least reaching a straight line connecting a center point of the emission port and a center of rotation of the rotation shaft to each other, from one end toward the other end.

Abstract: A water heater is provided that can suppress backflow (entry) of drainage water into a fan from downstream of the fan in a path of a flow of combustion gas. The fan includes a fan case, an impeller housed within the fan case, a drive source attached to the fan case so as to drive the impeller, and a rotation shaft connecting the impeller and the drive source. An exhaust connection portion has a connection portion case and is provided with an exhaust port for emitting combustion gas delivered from the fan to outside of the water heater. The exhaust connection portion also has a drainage water discharge portion for discharging drainage water accumulated downstream of the fan in the path of the flow of combustion gas.

Abstract: There is provided a flame hole formation member 7 which is inserted and mounted from above in a third plate member 6 used to form a central rich-side flame hole row 33. As the flame hole formation member 7, a pair of flame hole formation parts 71, 71 each used to form a respective lean-side flame hole row 34 are connected by bridge formation parts 72, 72 at their upper end positions, with a predetermined distance held between the flame hole formation parts 71, 71. The bridge formation part 72, 72 is fitted from above into an engagement groove 332 formed in the upper end edge of the third plate member 6, whereby the pair of the flame hole formation parts 71, 71 are assembled so as to sit astride the upper end edge of the third plate member 6.

Abstract: A fan includes: an impeller including a main plate having a first plane, a plurality of first blades each formed the first plane, and a shroud formed integrally with the plurality of first blades; a fan case; a drive source; and a rotation shaft. The first blades each include a linearly protruding region that is linearly increased in height from an outer circumferential side to an inner circumferential side, and a curvedly protruding region that is curvedly increased in height from the outer circumferential side to the inner circumferential side, the height extending in a direction in which each first blade protrudes. The linearly protruding region is welded to the main plate. Accordingly, a highly durable fan can be implemented that allows sufficient durability to be maintained even under a high temperature environment or an acid environment.

Abstract: A water heater capable of cooling a fan by inflow of air while suppressing backflow of combustion gas is provided. A fan includes: a fan case having a back surface wall; an impeller having a first blade and a second blade and housed in the fan case; a drive source rotating the impeller; and a rotation shaft coupling the impeller and the drive source through a through hole provided in the back surface wall. A gap through which air outside the fan case is suctioned into the fan case is provided between the rotation shaft and the back surface wall. The second blade faces the back surface wall without another member interposed therebeween throughout a range from an inner circumferential side to an outer circumferential side of the second plane.

Abstract: In a rich-lean combustion burner, each of outer rich-side flame holes disposed on both outer sides is supplied with rich-side mixture in the same amount and mixing state as the others. A lower end part of a central rich-side burner part is projected into an interior of a tubular part to which a rich-side mixture is introduced. First communication holes are opened, respectively, in both side walls of the lower end part. A second and a third communication holes in fluid communication with an outer rich-side burner part are opened in a tubular part. The second and the third communication holes are oriented so as to face each other without any obstruction, other than a space, therebetween. Furthermore, a pocket part which is a space part adapted to collect and accumulate dust particles is formed on the downstream side up to a closed end.

Abstract: A water heater of a latent heat recovery type includes: a combustion apparatus including a burner having a plurality of burner port portions and generating combustion gas from openings at ends of the plurality of burner port portions; a heat exchanger heating water that flows through inside by heat exchange with combustion gas generated in the combustion apparatus; and a fan suctioning the combustion gas that has passed through the heat exchanger and emitting combustion gas to outside of the water heater. The fan includes a fan case, an impeller housed within the fan case, and a drive source connected to the impeller. At least a part of an upper surface of a bottom wall of the fan case is inclined with respect to a reference plane including the openings of the plurality of burner port portions.