Abstract: A liquid heating apparatus includes: a liquid bath; a combustion chamber provided with a burner, and formed at one side on a lower portion of the liquid bath; and an exhaust pipe located horizontally in the liquid bath and extending from one side of the liquid bath toward the other side thereof. The apparatus heats the liquid bath by passing combustion gas generated in the combustion chamber into the exhaust pipe, with the exhaust pipe being formed into a cylinder shape having vertical side walls. A fin is integrally located on an inner surface of the side wall of the exhaust pipe along the longitudinal direction thereof. The fin has a predetermined heating surface chosen in accordance with a predetermined temperature gradient in a longitudinal direction of the exhaust pipe, and is located on only upper portion side on an inner surface of the exhaust pipe.

Abstract: A liquid heating apparatus is provided in which fins are directly secured and fixed at the bottom portion of a liquid tank to ensure sufficient heat efficiency with production cost reduced by simplification of the construction thereof and with maintenance being easily carried out. In the liquid heating apparatus which raises the temperature of liquid in a liquid tank by heating the bottom of said liquid tank with a burner disposed downward of the bottom of said liquid tank, an inclination plane which is inclined at a predetermined degree of angle and is formed on the bottom of said liquid tank, and long fins are fixed on the rear side of said inclination plane along the inclination direction thereof. The fins are provided with thermal expansion absorbing capabilities along the lengthwise direction thereof. The fins can be formed with channel-like cross sections, and the bottom wall portions thereof are fixed close to the rear side of the inclination plane of the liquid tank.

Abstract: The present invention provides a liquid heating apparatus which can obtain a sufficient heat efficiency by making large a heating surface area by a combustion gas flowing through an exhaust pipe located in a liquid bath. In a liquid heating apparatus which includes: a liquid bath; a combustion chamber which is provided with a burner, and is formed at one side on a lower portion of the liquid bath; and an exhaust pipe which is located in a substantially horizontal state at an intermediate portion of the liquid bath, and extends from one side of the liquid bath toward the other side thereof, and which heats a liquid in the liquid bath bypassing a combustion gas generated in the combustion chamber into the exhaust pipe, a fin is integrally located on an inner surface of the exhaust pipe along a longitudinal direction thereof.

Abstract: A novel liquid heating apparatus is provided by which sufficient heat efficiency is achieved with the production cost reduced by simplification of the construction thereof, and the maintenance of which is easily carried out. The liquid heating apparatus is provided with a burner unit disposed downward of the bottom portion of a liquid tank formed to be a rectangular parallelpiped in its plan view for raising the temperature of the liquid in the liquid tank by heating the bottom portion of the liquid tank using a burner of the burner unit. A heating plane opposite flame ports of the burner and a low temperature portion located downward of the heating plane are formed at the bottom portion of the liquid tank. Fins protruding toward the burner direction are juxtaposed and fixed on the rear side of the heating plane in the lengthwise direction thereof. A fan capable of generating a flow of combustion gas among the fins is provided in the burner unit.