A water heater includes a primary heat exchanger, a secondary heat exchanger disposed above the primary heat exchanger, a flow path member, and a flow restriction member. The secondary heat exchanger includes a case and heat transfer pipes arranged in the case. The case includes a wall having a gas inlet through which combustion exhaust gas discharged from the primary heat exchanger is introduced into the case. The flow path member connects the primary heat exchanger and the secondary heat exchanger and is disposed adjacent to the gas inlet and is configured to introduce the combustion exhaust gas discharged from the primary heat exchanger into the secondary heat exchanger through the gas inlet. The flow restriction member is disposed on the wall of the case to suppress upward flowing of the combustion exhaust gas that is introduced into the case through the gas inlet.

The invention is directed to a liquid heater for rapidly heating a liquid without overheating the liquid. The liquid heater comprises a liquid flow channel having a passage through which liquid flows, a heating part disposed outside the liquid flow channel, a heat reflecting part facing a heat radiating side of the heating part, and a cooling part through which a cooling medium flows adjacent a reverse side of a reflecting surface of the heat reflecting part for cooling the heat reflecting part. Radiant heat not absorbed in the liquid is reflected by the heat reflecting part. The heat reflecting part reflects radiant heat cooled by the cooling part so that the body of the liquid heater and peripheral members are maintained at a temperature not higher than a predetermined temperature to prevent overheating the liquid.

A heat exchanger having a first heat exchanger tube and a second heat exchanger tube is disclosed. The first heat exchanger tube can have a first leg, a second leg, and a bend section, and the bend section of the first heat exchanger tube can include three or more bends, each of the three or more bends having a corresponding bend angle that is less than or equal to approximately 90 degrees. The second heat exchanger tube can have a first leg, a second leg, and a bend section, and the bend section of the second heat exchanger tube can include three or more bends, each of the three or more bends having a corresponding bend angle that is less than or equal to approximately 90 degrees.

The invention relates to a device for heating a fluid (2), comprising a heating body (4) having a through passageway (6, 8) for the fluid and provided with at least one groove (14) on its outer surface; at least one electrical resistance (24) housed in the at least one groove (14) of the heating body. The device further comprises at least one closure plate (20) of the at least one groove (14) overlying the at least one resistance (24).

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.

The invention provides a device (200, 300, 400) for heating a continuous flow fluid. Said device (200, 300, 400) consists of a steel conduit (3, 3′, 3″) through which the fluid to be heated flows and of at least one sheathed resistor (2, 2c, 2d, 2e, 2f) that is parallel to the steel conduit (3, 3′, 3″) and that is in thermal contact therewith. The steel conduit (3, 3′, 3″) and the at least one heating element (2, 2c, 2d, 2e, 2f) are incorporated in a die-casting element made of an aluminium alloy.

The present description discloses a combustion type water heater that heats water by burning fuel. The combustion type water heater includes: a burner that generates combustion gas by burning the fuel; a heat exchanger that exchanges heat between the water passing through on an inside of the heat exchanger and the combustion gas flowing on an outside of the heat exchanger, an exhaust pipe that discharges the combustion gas after the heat exchange in the heat exchanger as exhaust gas; an exhaust gas temperature detector that detects a temperature of the exhaust gas flowing in the exhaust pipe as an exhaust gas temperature; a clog degree detector that detects a degree of clog in the exhaust pipe; and a scale buildup determiner that determines whether or not scale has built up inside the heat exchanger based on the exhaust gas temperature and the degree of clog in the exhaust pipe.

A heat exchange device for heating liquid adhesive material to an application temperature suitable for an adhesive bonding application includes a body having an inlet configured to receive a flow of liquid adhesive material and an outlet configured to provide the liquid adhesive material to a dispensing device for the adhesive bonding application. A fluid passageway in the body connects the inlet and the outlet. The fluid passageway includes a thin slit section in the form of an elongated ring shape, having a length along a fluid flow direction between the inlet and the outlet, the thin slit section further having a first dimension and a second dimension transverse to the fluid flow direction. The first dimension and the length are substantially greater than the second dimension. The heat exchange device further includes a heating element for heating the liquid adhesive material flowing through the thin slit section.

Provided is a hot water supply apparatus. Processing executed by the hot water supply apparatus includes the following. A hot water supply set temperature is read from a memory. A maximum temperature of a housing is set by combustion level (combustion stage number) in accordance with a setting pattern predetermined according to the hot water supply set temperature. When it is intended to detect an end of operation of the hot water supply apparatus in the case of detecting no change in the hot water supply set temperature, a combustion operation is continued. The maximum temperature of the housing is set again by combustion level (combustion stage number) in the case of detecting a change in the hot water supply set temperature.

A heater for heating liquid to boiling comprises a heating element (48; 106), a first heating region (18, 20; 100) heated by said heating element (48; 106) for heating liquid flowing therethrough to a temperature below boiling, and a second heating region (22; 102) for heating said liquid to boiling. The second region permits the exit of steam therefrom separately from heated water.