Abstract: A premixing device which includes a premixing flow path including a first flow path and a second flow path, and a first fuel gas outlet and a second fuel gas outlet includes: a first blade section which is provided in the first flow path, and with which the first fuel gas outlet is provided; a protruding wall section which is provided on the first blade section; and a flapper which oscillates at a position downstream in the air flow direction than the first blade portion of the first flow path. When the flapper is in an open state below a specified opening degree, the flow of air from the first flow path to the first fuel gas outlet is capable of being suppressed by the protruding wall section.

Abstract: A premixing device includes: a blade, arranged midway of a gas flow path through which air flows, and provided with a fuel gas outlet in a region near one end downstream in an air flow direction; a pair of divided flow paths, configured by dividing a portion of the gas flow path by the blade; and a baffle, located upstream of the fuel gas outlet in the air flow direction on an inner peripheral surface of each divided flow path, and being in the shape of a protruding piece or step part protruding inward of each divided flow path. The baffle is provided in at least a portion of an inner region of each divided flow path, and makes it possible to increase a flow velocity of air flowing through an outer region to be higher than a flow velocity of air passing through the inner region.

Abstract: The invention provides a water heater WH including first and second connection target parts J1, J2 that are, as a means for connecting a burner unit BU and a heat exchanger HE, frame-like parts provided at opening edge parts of a first case 1 of the burner unit and a second case 2 of the heat exchanger, respectively, and sandwich a sealing member 5 to face and be connected with each other. An entire shape of the sealing member is frame-like corresponding to the first and second connection target parts, and a notched concave part 50 or a non-notched hole part 50A is formed at a portion thereof. A heat transfer convex part 15 is provided at at least one of the first and second connection targets, and protrudes to enter the concave part or the hole part to come into surface contact with the other.

Abstract: A premixing device includes: a gas flow passage forming member in which an x direction is used as an axial length direction, and a Venturi-shaped gas flow passage into which air can flow in from the outside is formed inside; and a blade portion positioned in the gas flow passage, extending in a y direction, and equipped with a fuel gas outlet. The blade portion includes first and second blade portions spaced apart from each other in a z direction, and an air flow path near the center through which a part of the air flows is formed between these first and second blade portions. At least one of a pair of surfaces of the first and second blade portions facing each other is equipped with an inner bulging portion that bulges in the z direction so as to squeeze a part of the air flow path near the center.

Abstract: A premixing flow path forming member of a premixing device includes a member whose attachment mode can be changed, and flow path resistance of a fuel gas flow path can be changed when the attachment mode of the member is changed.

Abstract: A water heating device equipped with a housing, a fan and a chamber arranged in the interior of the housing, and screws. The housing has first and second side plates which oppose one another in a first direction and extend from the ends of a back plate along a second direction intersecting the first direction. An opening part is provided in the housing on the side opposite the back plate in the second direction. The fan has a discharge opening, a first flow passage extending along the first direction, and a first flange. The chamber has an intake opening, a second flow passage extending along the first direction, and a second flange. The first and the second flanges are secured by screws. In a planar view, the center axis of the screws is slanted such that a head portion is closer to the opening part than the tip-end portion.

Abstract: A premixing flow path forming member of a premixing device includes a member whose attachment mode can be changed, and flow path resistance of a fuel gas flow path can be changed when the attachment mode of the member is changed.

Abstract: A premixing device includes: a gas flow passage forming member in which an x direction is used as an axial length direction, and a Venturi-shaped gas flow passage into which air can flow in from the outside is formed inside; and a blade portion positioned in the gas flow passage, extending in a y direction, and equipped with a fuel gas outlet. The blade portion includes first and second blade portions spaced apart from each other in a z direction, and an air flow path near the center through which a part of the air flows is formed between these first and second blade portions. At least one of a pair of surfaces of the first and second blade portions facing each other is equipped with an inner bulging portion that bulges in the z direction so as to squeeze a part of the air flow path near the center.

Abstract: A water heating device equipped with a housing, a fan and a chamber arranged in the interior of the housing, and screws. The housing has first and second side plates which oppose one another in a first direction and extend from the ends of a back plate along a second direction intersecting the first direction. An opening part is provided in the housing on the side opposite the back plate in the second direction. The fan has a discharge opening, a first flow passage extending along the first direction, and a first flange. The chamber has an intake opening, a second flow passage extending along the first direction, and a second flange. The first and the second flanges are secured by screws. In a planar view, the center axis of the screws is slanted such that a head portion is closer to the opening part than the tip-end portion.