Abstract: A water heater with two non-condensing flues and a condensing flue(s) having a system to prevent condensation in the non-condensing flue(s). The downwardly extending first flue is connected by a 180 degree connector to an upwardly extending second flue. Between the non-condensing and the condensing flues is positioned a temperature sensor. A controller receives input from the temperature sensor and is connected to the burner to control the minimum power setting and duration so as to prevent the combustion gases from falling below a temperature at which water will condense at the temperature sensor so no condensation occurs in the first two flues. Burner power settings are minimized near a water tank setpoint to improve efficiency by increasing condensation.

Abstract: A water heater with two non-condensing flues and a condensing flue(s) having a system to prevent condensation in the non-condensing flue(s). The downwardly extending first flue is connected by a 180 degree connector to an upwardly extending second flue. Between the non-condensing and the condensing flues is positioned a temperature sensor. A controller receives input from the temperature sensor and is connected to the burner to control the minimum power setting and duration so as to prevent the combustion gases from falling below a temperature at which water will condense at the temperature sensor so no condensation occurs in the first two flues. Burner power settings are minimized near a water tank setpoint to improve efficiency by increasing condensation.

Abstract: A water heater has a tank having an upper and a lower domes which are penetrated by tubular flues in a 1-1-5 arrangement of a first flue connected to a second flue which in turn is connected to tertiary condensing flues. A gas-fired burner on the upper dome fires into the first flue. Both the first and second flue have heat exchange capacity enhanced by a multiplicity of rectangular metal fins welded in a helical arrangement. Some or all of the fins in the first flue may be stainless steel, while the remaining fins may be a different material, such as mild steel. The first and second flues are arranged to remove approximately 82-89 percent of the heat generated by the burner with minimal or no formation of condensate. Approximately 5.5-9 percent of the heat generated by combustion in the burner is removed in third flues where condensation takes place.

Abstract: An enamel flow coating process and apparatus is arranged as a four arm Ferris wheel like apparatus which is mounted over a bathtub like tank which holds enamel slip. Coils of steel tubing formed into heat exchangers are mounted to the arms of the wheel to rotate and to pivot. The wheel is rotated between four stations. In the first station, a coil is loaded onto the wheel. In a second station the coil is pivoted into the tank of enamel slip, where it is coated, and withdrawn by operation of a pivoting bracket. The coated coils are rotated through third and fourth stations where the coating solidifies, and the coated heat exchanger is removed, and replaced with an uncoated one in the first station. After leaving the wheel, the heat exchanger is fired and installed in a water storage tank.

Abstract: A water heater has a tank having an upper and a lower domes which are penetrated by tubular flues in a 1-1-5 arrangement of a first flue connected to a second flue which in turn is connected to tertiary condensing flues. A gas-fired burner on the upper dome fires into the first flue. Both the first and second flue have heat exchange capacity enhanced by a multiplicity of rectangular metal fins welded in a helical arrangement. Some or all of the fins in the first flue may be stainless steel, while the remaining fins may be a different material, such as mild steel. The first and second flues are arranged to remove approximately 82-89 percent of the heat generated by the burner with minimal or no formation of condensate. Approximately 5.5-9 percent of the heat generated by combustion in the burner is removed in third flues where condensation takes place.

Abstract: A water heater has a burner positioned below a vertical centrally located flue with heat exchange capacity enhanced by a multiplicity of rectangular metal fins which are welded on the inside of the vertical central flue. The central flue extends upwardly within a water tank. The central flue transitions to a smaller diameter downwardly draining helically coiled condensing flue. Approximately 80% of the heat from the combustion gases is transferred to the water within the water tank through the wall of the central flue without condensation. An additional 10% or more of the combustion heat is transferred to the water accompanied by condensation of water in the coiled flue. A fan draws the combustion gases through the central flue and the coiled condensing flue and supplies the combustion gases to an exterior vent.

Abstract: A water heater has a burner positioned below a vertical centrally located flue with heat exchange capacity enhanced by a multiplicity of rectangular metal fins which are welded on the inside of the vertical central flue. The central flue extends upwardly within a water tank. The central flue transitions to a smaller diameter downwardly draining helically coiled condensing flue. Approximately 80% of the heat from the combustion gases is transferred to the water within the water tank through the wall of the central flue without condensation. An additional 10% or more of the combustion heat is transferred to the water accompanied by condensation of water in the coiled flue. A fan draws the combustion gases through the central flue and the coiled condensing flue and supplies the combustion gases to an exterior vent.

Abstract: An anode is mounted to the top of a water heater tank which has a spud with external threads welded to the top thereof. The spud extends above insulation which surrounds the water tank and covers the top of the water heater. An anode rod is inserted into the water tank through the spud and has a steel core welded to a flat cylindrical steel disk which extends radially outwardly of a magnesium cylinder formed about the core. A water sealing gasket is positioned between the disk and the annular surface formed by the open end of the spud. A nut fits over the disk and engages the threads on the spud, and clamps the anode to the spud so that the threads are isolated from water in the tank, allowing easy removal of the anode after the passage of time.

Abstract: An anode is mounted to the top of a water heater tank which has a spud with external threads welded to the top thereof. The spud extends above insulation which surrounds the water tank and covers the top of the water heater. An anode rod is inserted into the water tank through the spud and has a steel core welded to a flat cylindrical steel disk which extends radially outwardly of a magnesium cylinder formed about the core. A water sealing gasket is positioned between the disk and the annular surface formed by the open end of the spud. A nut fits over the disk and engages the threads on the spud, and clamps the anode to the spud so that the threads are isolated from water in the tank, allowing easy removal of the anode after the passage of time.

Abstract: A water tank has a central flue to which clips are welded. The clips define baffles and are welded to have a greater heat transfer area where they are joined to the central flue. The individual clips are rectangular and are welded to the flue wall along one side at an angle of 4° rather than the 9° of the prior art so that the clip has a greater weld area. This greater weld area increases the thermal path between the clip and the wall of the central flue.