A heat exchanger for heating a fluid flowing through a pipe using a combustion gas includes: a body including open upper and lower ends and having a space formed therein to allow the combustion gas to pass therethrough; a combustor formed in an upper portion of the space in which combustion of the combustion gas occurs; a heat exchange portion formed below the combustor and provided with a heat exchange pipe configured to heat an internal fluid by using the combustion gas; and a heat return pipe provided outside the space so as to be in contact with an outer surface of the body, wherein the combustor and the heat exchange portion may be unitarily formed, and the body in which the combustor is formed includes a concave portion protruding concavely inward so as to correspond to a shape of an outer circumferential surface of the heat return pipe.

A water heater has one or more heating elements and an internal wall that causes an increased rate of heating within a sub-volume within the water heater tank. Water from the sub-volume is directed to the tank outlet.

A vent attachment facilitates attaching a coaxial air intake and exhaust vent of a tankless water heater to a Category I vent, such as B-vent. The vent attachment comprises a first end with a coaxial connector comprising a central exhaust pathway and a circumferential air intake pathway. The vent attachment also comprises a second end with a tubular exhaust vent connector in fluid communication with the central exhaust pathway. The vent attachment further comprises a frame that encloses the central exhaust pathway and comprises a mesh configured to provide fluid communication through the frame with the air intake pathway. Additionally, operation of the tankless water heater is modified to ensure that the exhaust generated is suitable for venting through a Category I vent. The tankless water heater maintains a high fuel consumption rate such that the temperature of hot water produced increases throughout each of a plurality of burner stages.

A PTC liquid heating device comprises a housing extending along a longitudinal axis and defining a liquid inlet and a liquid outlet. A PTC heating unit is inserted into the housing and extends along the longitudinal axis. The PTC heating unit includes a sleeve, a heat conductor and at least one PTC heating core. The heat conductor has a pair of metal profiles defining at least one chamber, the at least one chamber extending along the longitudinal axis to receive the at least one PTC heating core. The heat conductor is located in the sleeve and has a shape matching the sleeve. The PTC liquid heating device provides uniform and efficient heat transfer. In addition, the PTC liquid heating device has improved corrosion resistance and insulation properties, thereby prolonging the service life of the PTC liquid heating device.

A tooling and method for flexible through connection of a double-liner water heater. The tooling includes a transition shaft, a tooling connecting plate and a fastening screw. The method includes: allowing a shaft head of the transition shaft to be in fit with an inner surface of an outer flange of a lower liner for welding; allowing an end hole to be in fit with an outer surface of an inner flange of an upper liner for welding; after welding seams are cooled, removing the tooling, and enameling the upper and liners; forming through-flexible connection between the inner and outer flanges; and firmly fitting the upper and lower liners together with two steel strips to ensure that a gap between the upper and lower liners is not greater than 7 mm.

A water heater connectable to an external air supply and exhaust pipe includes a housing that houses a combustion device, a connecting portion, a first air supply and exhaust pipe, and a second air supply and exhaust pipe. The connecting portion includes an outer cylinder and an inner cylinder projecting upward from an upper surface of the housing. The first air supply and exhaust pipe and the second air supply and exhaust pipe are selectively connectable to the connecting portion. The first air supply and exhaust pipe is connectable to the connecting portion by interpolating a first air supply pipe into the outer cylinder and interpolating a first exhaust pipe into the inner cylinder, and the second air supply and exhaust pipe is connectable to the connecting portion by externally fitting a second air supply pipe onto the outer cylinder and interpolating a second exhaust pipe into the inner cylinder.

An electric roofing torch comprising a tubular body having an upstream end and a downstream end, a fan unit mounted in the tubular body to drive a flow of air through the tubular body and a heater tube comprising a heater matrix, the heater tube being mounted in the tubular body to heat the flow of air as it passes through the tubular body. The fan unit comprises an electric vaneaxial fan which is mounted upstream of the heater tube. The fan unit is mounted in the tubular body to drive a flow of air through the tubular body at velocity, pressure and volume that is sufficient for roofing operations such as laying roofing membranes, with zero carbon emissions. There is also provided a method of providing a working flow of hot air from the electric roofing torch for such a roofing operation.

Improved steamblow commissioning of a steam plant with steam discharged to the condenser and increased use of permanent piping instead of temporary piping with quenching/desuperheating and providing a low back pressure environment to enable aggressive steam blow cleaning.

A heating apparatus is disclosed. The heating apparatus comprises a PTC heating element, a first electrode, a second electrode, a first protection layer, a second protection layer, a first interlayer, and a second interlayer. A hardness of the first protection layer is greater than that of the first interlayer. A hardness of the second protection layer is greater than that of the second interlayer.

A forced air heater that includes a temperature sensing device, the temperature sensing device includes: a sensing plate mounted on a metallic component in the environment to be heated; and an electrical contact connected to the sensing plate, wherein the electrical contact is thermally coupled with the metallic component via the sensing plate. There is further provided a method of controlling a heater that includes a temperature sensing device that it is thermally connected to a solid component in the environment to be heated.