Combustion device

A combustion device comprising:

• an outer casing;
• and
• a combustion device main body housed in the outer casing, wherein
• the outer casing has a casing body having a front opening which opens frontward, and a front cover closing the front opening of the casing body and having an exhaust port member insertion hole,
• the combustion device main body has a burner which ejects mixture gas downward for combustion to generate combustion exhaust gas, a combustion box accommodating therein a heat exchanger heated by the combustion exhaust gas and disposed below the burner, an exhaust duct connected to an outlet port of the combustion box such that the combustion exhaust gas flows therein, and an exhaust port member connected to a downstream end of the exhaust duct to discharge the combustion exhaust gas to an outside,
• the exhaust duct includes a riser duct section extending from the outlet port of the combustion box to a predetermined position above the burner through behind the combustion device main body, and a horizontal duct section bent from an upper end of the riser duct section, extending toward the front cover, and connected to the exhaust port member,
• the exhaust port member has an upper wall portion and a lower wall portion separated from each other in an up-down direction, a left wall portion, and a right wall portion such that an exhaust passage is formed inside the exhaust port member,
• the exhaust port member has an elongated front end opening flat in a left-right direction and an elongated back end opening flat in the left-right direction,
• the upper wall portion and the lower wall portion of the exhaust port member protrude frontward from an inside of the outer casing through the exhaust port member insertion hole of the front cover,
• the lower wall portion of the exhaust port member is inclined upward toward the front end opening,
• an upper inner wall surface of the upper wall portion of the exhaust port member has a first upper inner wall surface portion extending from the front end opening to a predetermined position which is located backward of the front end opening, an upper protruding wall surface portion protruding inward of the exhaust passage from a back end of the first upper inner wall surface portion over the entire exhaust passage in the left-right direction, and a second upper inner wall surface portion extending from an inner end of the upper protruding wall surface portion toward the back end opening,
• the exhaust passage which is located forward of the upper protruding wall surface portion expands upwardly as compared with the exhaust passage which is located backward of the upper protruding wall surface portion,
• the second upper inner wall surface portion is inclined upward toward the front end opening, and
• in a cross section in a front-back direction, an inclination angle of the second upper inner wall surface portion with respect to a horizontal plane is smaller than an inclination angle of a virtual line connecting the inner end of the upper protruding wall surface portion and a front end of the first upper inner wall surface portion forming the front end opening with respect to the horizontal plane.