Patent application title: Gas hot water heater preheater
Paul Tyler (Oakland, CA, US)
IPC8 Class: AF22D116FI
Class name: Liquid heaters and vaporizers feed heaters water tube boiler
Publication date: 2012-11-15
Patent application number: 20120285399
A modified portion of gas hot water heater exhaust vent tubing. Cold
water tubing is wound around the outside of a tube of the same interior
diameter and vertical orientation as the exhaust vent tube that typical
gas hot water heaters are designed to operate with. Said vent tube is
insulated, double-walled, or is otherwise of a sufficient thickness
and/or appropriate material composition so as to prevent condensation
occurring on its interior surfaces, and may contain small vents or
perforations that allow hot exhaust gases to communicate with the cold
water tubing. An insulating jacket is located proximally to the cold
water tubing whereby the insulating jacket, cold water tubing and vent
tube portion are enclosed within a housing portion. The present invention
is meant to easily replace an existing section of exhaust venting
typically used in a consistent vertical orientation with a common gas hot
1. Cold water tubing comprising an intake end, an outflow end, and a
coiled portion whereby said coiled portion is located proximally around
an interior vent tube that includes a top and bottom end, and whereby
cold water flow is directed into said intake end, through said coiled
portion, and out of said outflow end, and whereby said interior vent tube
top and bottom ends may include a coupling means whereby: said bottom end
may be attached to: the exhaust vent port of a gas hot water heater;
standard vent tubing; and/or the top end of a corresponding additional,
separate section of preheater; said top end may be attached to standard
vent tubing and/or the bottom end of an additional, separate section of
preheater; said cold water tubing intake end and outflow ends include
coupling means enabling: intake end attachment to cold water supply
piping and/or attachment to the cold water tubing outflow end of an
additional, separate section of preheater; and outflow end attachment to
a cold water tubing intake end and/or a gas hot water heater cold water
2. The preheater of claim 1 whereby insulating material is located proximally around said cold water tubing coiled portion and whereby a housing portion is located around or encloses: said insulation, said cold water tubing, and said interior vent tube.
3. The preheater of claim 1 whereby a housing portion is located proximally around or encloses said cold water tubing coiled portion and whereby insulating material is located proximally around: said housing portion, said cold water tubing, and said interior vent tube.
4. The interior vent tubing of claim 1 comprising a material composition and/or thickness sufficient to minimize condensation formation on its interior surfaces whereby: said interior vent tubing is comprised of materials including but not limited to: metal, metal alloys, glass, polymer, ceramic, stone, elastomer, or any combination thereof; said interior vent tubing comprises a singular portion or a plurality of portions of said materials whereby said portions are placed proximally to each other, or whereby said portions are separated by a small distance whereby air or insulating material, including insulating liquids or gels, is located between said portions; and said interior vent tubing may contain vents, perforations or openings, or singularities, or combinations thereof, whereby the hot exhaust gases from a gas hot water heater may come in contact with said cold water tubing in such a manner as to not create significant backpressure or otherwise to not interfere substantially with the operation of said gas hot water heater whereby it is caused to operate less efficiently or less safely.
5. The housing portion of claims 2 and 3 including a top and bottom end whereby said housing top and bottom ends are in an open and/or closed configuration whereby: a closed configuration comprises a housing end where the housing material is extends generally at angle to, and from and between the housing outer surfaces to the interior vent tube outer surfaces, thereby generally enclosing preheater components at that end; and said open configuration comprises a configuration where the housing material does not enclose preheater components at that end; and said housing open end configuration also comprises a coupling means for attachment of said housing top or bottom end to a corresponding housing top or bottom end coupling means of an additional, separate preheater section.
CROSS REFERENCE TO RELATED APPLICATIONS
 Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 Not Applicable.
BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to water heating devices commonly used for heating water for commercial and residential use. More specifically, the present invention relates to gas hot water heater preheaters or economizers.
 2. Description of Related Art
 Common gas hot water heaters utilize a pilot flame in conjunction with a gas supply for on demand ignition and subsequent heating of a water tank. A thermocouple is employed to close the valve controlling the gas supply if the pilot flame is extinguished so as to prevent unburned gas from being released. Blowers direct heated air onto the water tank so as to heat the water inside. The heated air is then directed into an exhaust vent typically located at the top of the water heater, and then carried through a vertically oriented 3 or 4 inch diameter vent pipe that typically extends through the top of a commercial or residential structure so as to release the exhaust gases to the outside air. A cold water supply line supplies water to the water tank inside the gas water heater.
 The prior art is crowded with devices called preheaters or economizers that utilize the hot air exhaust from a gas hot water heating device to preheat cold water before it enters the gas hot water heating device. Preheating the cold water causes the gas hot water heating device to perform more efficiently where less energy is required to heat preheated water.
 The prior art is generally made up of reservoir type preheaters and bubbler type preheaters. Reservoir type preheaters use gas hot water heater exhaust gas to heat a reservoir of cold water sitting over the gas hot water heater vent. Bubbler type preheaters force gas hot water heater exhaust gases through the cold water. U.S. Pat. No. 4,175,518 to Reames is a horizontally oriented chamber enclosing cold water piping arranged so that the hot water heater exhaust gas is initially forced through a right angle exhaust vent and into said horizontal chamber after which the exhaust gas exits said chamber through another right angle exhaust vent. The device to Reames is ostensibly caused to be horizontally oriented and positionally offset from the gas hot water heater exhaust opening to prevent condensation from entering the gas hot water heater and either: extinguishing the pilot flame; interfering with electronics; and/or interfering with thermocouple operation.
 There does not exist in the prior art, however, the present invention which comprises a modified portion of gas hot water heater exhaust vent tubing. The orientation, vent tubing diameter, and insulation design of the present invention is purposefully meant to permit a simple replacement of existing vertical exhaust tubing above a gas water heater with the present invention so as to not interfere with the operation characteristics that a gas water heater is calibrated to perform at. Cold water tubing is wound around the outside of a tube of the same interior diameter and vertical orientation as the exhaust venting that typical gas hot water heaters are designed to operate with. Said vent tube is insulated, double-walled, or is otherwise of a sufficient thickness and/or appropriate material composition so as to prevent condensation occurring on its interior surfaces, and may contain small vents or perforations that allow hot exhaust gases to communicate with the cold water tubing. An insulating jacket is located proximally to the cold water tubing whereby the insulating jacket, cold water tubing and vent tube portion are enclosed within a housing portion. The present invention is meant to easily replace an existing section of exhaust venting typically used in a consistent vertical orientation with a common gas hot water heater.
SUMMARY OF THE INVENTION
 The general purpose of the foregoing application is to describe an improved preheater, heat exchanger, or economizer for use with a common gas hot water heater whereby an exhaust vent is used to transport hot exhaust gases created by the gas hot water heater away from the gas hot water heater.
 The present invention presents as a straightforward replacement of the existing vertically oriented 3 or 4 inch diameter vent piping typically used with common gas hot water heaters, whereby the present invention describes a gas water heater preheater. The present invention reroutes the gas water heater cold water supply piping so that cold water enters the preheater, collects heat, exits the preheater and then enters the cold water intake of the hot water heater as preheated water.
 The elements of the present invention preheater include in part: a 3 or 4 inch diameter interior tube portion; a coiled cold water tubing portion positioned helically around the exterior of said interior tube portion; an insulating jacket; and a housing portion surrounding or enclosing the aforementioned elements. In an alternative embodiment, a housing is located proximally to the cold water tubing and an insulating jacket surrounds or encloses the housing and cold water tubing. The interior tube portion bottom end is attached to the water heater exhaust vent via an exhaust port coupling means, and the interior tube top end is attached to contiguous vent tubing via a top end coupling means. The interior tube is insulated, double-walled, or is otherwise of a sufficient thickness and/or of appropriate material composition so as to prevent condensation occurring on its interior surfaces. A single embodiment of the aforesaid elements may comprise an entire preheater, or, a plurality of embodiments may comprise corresponding sections of an entire preheater whereby corresponding sections are attached to each via respective element coupling means thereby allowing a preheater to be of any desired length.
 The hot water heater exhaust gases contain considerable heat as they exit the water heater exhaust vent and enter the interior tube of the preheater. Small vents or perforations in the wall of the interior tube allow said hot gases to flow through the preheater and heat the coiled cold water tubing, thereby preheating the cold water inside said tubing. An insulating jacket located proximally to the coiled cold water tubing slows heat loss within said tubing while allowing exhaust gases to flow past.
 The characteristics and utilities of the present invention described in this summary and the detailed description below are not all inclusive. Many additional features and advantages will be apparent to one of ordinary skill in the art given the following drawings, specifications and claims. There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
 In this respect, by explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
 As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
 Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
 It is therefore a purpose of the present invention to preheat cold water before it enters a gas hot water heater.
 It is therefore a purpose of the present invention to represent a simple replacement for 3 or 4 inch exhaust vent tubing commonly used with typical gas hot water heaters and that typically extend vertically through a roof opening so as to transport gases to the outside air.
 It is therefore a purpose of the present invention to present, in installation, as a single embodiment or as a plurality of sections, whereby corresponding embodiments are attached at respective component top and bottom ends enabling the creation of a preheater of any length starting from a gas hot water heater exhaust port.
 It is therefore a purpose of the present invention to function in such a manner so as to not interfere with the operation characteristics that a typical gas hot water heater is calibrated to operate at, including but not limited to safety and efficiency.
 It is therefore a purpose of the present invention to function in such a manner so as to not interfere with the safe use of a typical gas hot water heater.
 It is therefore a purpose of the present invention to prevent condensation created due to heat exchange from entering the gas hot water heater.
BRIEF DESCRIPTION OF THE DRAWINGS
 The present invention may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. For ease of understanding and simplicity, common numbering of elements within the illustrations is employed to identify an element in the different drawings.
 FIG. 1 is: a plain view of a cross section of the present invention including: an exterior housing portion (with closed top end and an open bottom end; the insulating jacket; and the interior vent tube); and the cold water tubing arranged helically around the interior vent tube.
 FIG. 2 is: a plain view of a cross section of the present invention including: an exterior insulating jacket and interior housing portion located proximally around the cold water tubing.
 FIG. 1 shows an embodiment of the present invention that includes a housing portion 200 with a closed top end 210 and an open bottom end. It is also anticipated that the housing 200 at the preheater top end and/or the preheater bottom end are in a closed configuration, whereby the housing extends to and around the interior vent tube 100. It is also anticipated that both the housing top and bottom ends are closed. In addition, any of the embodiments described above may comprise sections of preheater that are attached to one another, whereby the preheater is ultimately comprised of a plurality of these sections. By way of example, to make a 4 foot preheater an installer could: attach a 1 foot embodiment with a closed bottom end and open top end to the water heater exhaust vent; attach by stacking vertically and contiguously to the previous, two identical 1 foot embodiments with open top and bottom ends; and attach to the upper 1 foot section with both open ends, an embodiment with an open bottom end and closed top end. By way of a second example, a single embodiment with an open bottom and an open top end may comprise the entire preheater. Where the housing portion has a closed top or bottom end, it is to be understood that the portion enclosing or nearly enclosing the interior vent tube may be generally conical in shape. A coupling means is employed to attach the preheater bottom end to the water heater exhaust, including but not limited corresponding male/female tube ends that may employ openings 15 in a female end through which bolts or screws are employed to hold a male end in place. Yet another embodiment is shown in FIG. 2 whereby the housing is located proximally around and/or enclosing the cold water tubing with the insulating jacket located around the exterior surfaces of the housing portion.
 The composition of the housing portion 200 and the interior vent tube portion 100 may include but is not limited to: metal; metal alloys; glass; polymers; ceramics; stone; elastomer; or any combination thereof. The thickness of the interior vent tube and/or the thermal characteristics of its composition material(s) should be able to withstand temperature differentials during heat exchange so as to not cause condensation to form on its interior surfaces, and may be comprised of a plurality of layers (single wall, double wall, etc.) whereby each layer may be of the same or different material and may contain solid, liquid or gas insulating material between said layers. The insulating jacket portion 220 may be comprised of ceramic fiber or any suitable insulating material, or may comprise an insulating membrane containing liquid or gas.
 Small vents or perforations 25 in the interior vent tube portion may be employed to allow water heater exhaust gases into and/or through the portion of the preheater containing the cold water tubing. Said vents or perforations are of appropriate shape, and located sufficiently above the preheater bottom end, so as to prevent condensation formed during heat exchange to be allowed into the water heater exhaust vent opening.
 The cold water tubing 300 preferably ascends helically around the exterior of the interior vent tube whereby an opening or openings are located in the housing portion to permit cold water tubing to enter (intake end 320) and exit (outflow end 340) the preheater. Preheater cold water tubing intake and outflow ends may be at opposite ends of the preheater or located proximally to each other whereby the outflow end preferably transverses the coils of the cold water tubing 300 so that the transverse portion of the cold water tubing remains inside the preheater. The cold water tubing composition may include but is not limited to: metal; metal alloys; glass; ceramic; stone; polymer; or any combination thereof. The cold water tubing may be of uniform or different diameter(s) and/or of any shape.
 The previous is a detailed description of illustrative embodiments of the present invention. As these embodiments of the present invention are described with references to the aforementioned drawings, various modifications or adaptations of the methods and or specific structures described may become apparent to those skilled in the art. All such modifications, adaptations, or variations that rely upon the teachings of the present invention, and through which these teachings have advanced the art, are considered to be within the spirit and scope of the present invention. Hence, these descriptions and drawings are not to be considered in a limiting sense, as it is understood that the present invention is in no way limited to the embodiments illustrated.