US 8,807,093 B2Granted

Water heater with multiple heat exchanging stacks

AssigneeBock Water Heaters, Inc.

InventorMichael B. Steinhafel

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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.

Claims20

Dependent claims

A water heater comprising:

a water tank having a lower dome and an upper dome, and a tank wall extending therebetween;
a first flue defining a first flue wall, the first flue extending between the upper dome and the lower dome, the first flue joining the upper dome to define an opening through the upper dome, and joining the lower dome to define an opening through the lower dome, the first flue having an inner surface to which a first multiplicity of radially inwardly extending metal fins are attached by a weld, without extending through the first flue wall;
a burner mounted to the first flue so as to fire along the first flue;
a controller connected to the burner to vary the BTU output of the burner;
a second flue defining a second flue wall, the second flue extending along a length between the upper dome and the lower dome and spaced from the first flue, the second flue joining the upper dome to define an opening through the upper dome, and joining the lower dome to define an opening through the lower dome, the second flue having an inner surface to which a second multiplicity of radially inwardly extending metal fins are attached by a weld, without extending through the second flue wall;
a first thermal junction box mounted to one of the upper dome or the lower dome and forming a passageway between the first flue and the second flue, the first junction box opposite the burner so that flue gases pass through the first flue and then pass through the second flue;
and
wherein the multiplicity of metal fins in the first flue begin at a location spaced downstream from the burner such that the multiplicity of metal fins are exposed to lower temperature, and the multiplicity of metal fins in the first flue extend along the first flue inner surface to the first thermal junction box, and wherein the second multiplicity of metal fins extend along the second flue inner surface.

5 more elements

A water heater comprising:

a water tank having a lower dome and an upper dome, and a cylindrical tank wall extending therebetween;
a first cylindrical flue defining a first flue wall, the first cylindrical flue extending between the upper dome and the lower dome, the first cylindrical flue joining the upper dome to define an opening through the upper dome, and joining the lower dome to define an opening through the lower dome, the first cylindrical flue having an inner surface to which a first multiplicity of discrete radially inwardly extending metal fins are attached by a weld, without extending through the first flue wall;
a burner positioned on the upper dome and mounted to fire down the first cylindrical flue toward the opening in the lower dome;
a controller connected to the burner to vary the BTU output of the burner;
a second cylindrical flue defining a second flue wall, the second cylindrical flue extending between the upper dome and the lower dome and spaced from the first cylindrical flue, the second cylindrical flue joining the upper dome to define an opening through the upper dome, and joining the lower dome to define an opening through the lower dome, the second cylindrical flue having an inner surface to which a second multiplicity of discrete radially inwardly extending metal fins are attached by a weld, without extending through the second flue wall;
a first thermal junction box mounted to the lower dome and forming a passageway between the first cylindrical flue and the second cylindrical flue;
a plurality of third cylindrical flues extending between the upper dome and the lower dome and spaced from the first cylindrical flue and the second cylindrical flue, the plurality of third cylindrical flues joining the upper dome to define a plurality of third openings through the upper dome, and joining the lower dome to define a plurality of openings through the lower dome;
a second thermal junction box mounted to the upper dome and into which the second cylindrical flue and the plurality of third cylindrical flues open so that the second thermal junction box forms a passageway between the second cylindrical flue and each third cylindrical flue;
and
a final junction box mounted to the lower dome and covering the openings through the lower dome defined by the plurality of third cylindrical flues, the final junction box connecting to a condensate drain and a combustion gas exhaust pipe.

7 more elements

A water heater comprising:

a water tank having a lower dome and an upper dome, and a cylindrical tank wall extending therebetween;
a first cylindrical flue defining a first flue wall, the first cylindrical flue extending between the upper dome and the lower dome, the first cylindrical flue joining the upper dome to define an opening through the upper dome, and joining the lower dome to define an opening through the lower dome, the first cylindrical flue having an inner diameter to which a first multiplicity of discrete metal fins are attached by a weld, without extending through the first flue wall;
wherein at least some of the discrete metal fins in the first cylindrical flue which are positioned downstream of and closest to the burner are formed of a first metal with a capacity of continuous use at a first maximum temperature;
a burner positioned on the upper dome and mounted to fire down the first cylindrical flue toward the opening in the lower dome;
a second cylindrical flue defining a second flue wall, the second cylindrical flue extending between the upper dome and the lower dome and spaced from the first cylindrical flue, the second cylindrical flue joining the upper dome to define an opening through the upper dome, and joining the lower dome to define an opening through the lower dome, the second cylindrical flue having an inner diameter to which a second multiplicity of discrete metal fins are attached by a weld, without extending through the second flue wall;
wherein at least some of the discrete metal fins in the second flue are of a second metal different than the first metal with a capacity of continuous use at a second maximum temperature lower than the first maximum temperature;
a first thermal junction box mounted to the lower dome and forming a passageway between the first cylindrical flue and the second cylindrical flue;
a plurality of third cylindrical flues extending between the upper dome and the lower dome and spaced from the first cylindrical flue and the second cylindrical flue, the plurality of third cylindrical flues joining the upper dome to define a plurality of openings through the upper dome, and joining the lower dome to define a plurality of openings through the lower dome;
a second thermal junction box mounted to the upper dome and into which the second cylindrical flue and the plurality of third cylindrical flues open so that the second thermal junction box forms a passageway between the second cylindrical flue and each of the plurality of third cylindrical flues;
and
a final junction box mounted to the lower dome and covering the openings through the lower dome defined by the plurality of third cylindrical flues, the final junction box connecting to a condensate drain and a combustion gas exhaust pipe.

8 more elements

Dependencies are inferred from the claim text.