MXPA96005625A - Water heater presenting a molded plastic storage tank, and methods defafricacion asocia - Google Patents

Abstract

The present invention relates to an apparatus for storing water characterized in that it comprises: a plurality of hollow tubular body sections, of a molded piece of plastic, placed in a coaxial orientation, end to end, in which at least one pair of axially adjacent body sections and including first and second opposed end sections having closed outer ends, each of the body sections having at least one open end portion and further having: (i) an inner shell section tubular, (ii) a tubular outer shell section circumscribing coaxially to the inner tubular shell section and forming an annular insulating space between the inner and outer shell sections, and (iii) a series of circumferentially spaced ribs that are they extend radially through the annular isolation space and divide said annular isolation space into segm circumferential objects, the cones being molded intergrally with the inner and outer shell sections, each of the closed outer ends of the first and second end sections or end faces being integrally molded with said first and second opposite end sections; for sealingly and permanently joining the opposite and contiguous open end portions of each axially adjacent pair of the plurality of the sections of the body so as to form from the plurality of the body sections a body structure for storing water, hollow which presents a portion of a container for internal water storage completely defined by the inner shell sections, externally wrapped by the annular isolation spaces and structurally reinforced, via the ribs, by the extern shell sections

Description

WATER HEATER PRESENTING A STORAGE TANK PLASTIC MOLDING, AND ASSOCIATED MANUFACTURING METHODS BACKGROUND OF THE INVENTION The present invention relates generally to water heaters and in a preferred embodiment thereof more particularly relates to a specially designed water heater incorporating a water heater therein. of totally plastic storage, of the integrally molded water heater and an outer jacket construction. Using conventional construction techniques a water heater is typically manufactured by providing a metal storage tank adapted to contain an amount of water that will be heated and discharged from the tank later for use in a remote fixture such as a sink. The tank is externally insulated by wrapping it with an appropriate insulation material, such as fiberglass cover insulation and then placing an outer metal jacket structure around the insulation material to hold it in place or protect it from damage. Alternatively, the insulation cover can be omitted and a foam insulation can be injected into the space between the tank and the jacket structure. This typical three-component construction of the water heater (i.e. the separate metal tank, the outer metal jacket and the interior insulation means) has various well-known problems, limitations and disadvantages associated with it. For example, the indoor metal storage tank is heavy and, after a period of use, is subject to corrosion to an extent that requires the entire water heater to be replaced. Additionally, the fabrication of the water heater assembly in general requires a high work intensity, several stages of assembly and techniques that include tank formation, wrapping with insulation (or injection of foam-type insulation). the place) and the manufacture and installation of the structure of the outer metal jacket. This obviously adds a considerable cost to the finished water heater. In addition, the insulation and the structure of the outer jacket work mainly to thermally insulate the tank, and do not significantly strengthen the tank against the pressure of the water stored in it. Consequently, the separate metal tank must be designed to individually support the force of the stored water pressure, thereby increasing the required thickness (and therefore the weight) of the tank. As can be easily appreciated from the foregoing, it would be highly desirable to provide an improved water heater, associated manufacturing methods, which would eliminate or at least substantially reduce the problems, limitations and disadvantages mentioned above which are commonly associated with construction water heaters. of the type that was previously described in general form. It is consequently an object of the present invention to provide such an improved water heater and the associated manufacturing methods. BRIEF DESCRIPTION OF THE INVENTION In order to carry out the principles of the present invention, according to a preferred embodiment thereof, there is provided a water heater that includes a portion of a water storage tank comprising a plurality of body sections hollow tubular molded plastic piece which are preferably molded from a reinforced polypropylene base plastic material utilizing a structural foam plastic molding process. The sections of the body are arranged in an end-to-end coaxial orientation and include a first and second opposite end section having closed outer ends. In one embodiment of the water heater the plurality of body sections includes only the first and second opposite end sections mentioned above. In another modality, the plurality of body sections includes the first and second opposite end sections in conjunction with at least one open end body section interposed coaxially between the first and second opposite end sections. Each of the one-piece molded plastic body sections has (1) a tubular inner shell section, (2) a tubular outer shell section which coaxially surrounds the tubular inner shell section and which forms around it an annular isolation space, and (3) a series of circumferentially spaced ribs extending radially through the annular isolation space and dividing it into circumferential segments. The ribs are integrally molded with the inner and outer shell sections and each of the closed outer ends of the first and second opposite end sections are integrally molded with the balance of their associated outer end section. Joining means for joining are provided by sealing the opposite open end portions of each pair axially adjacent to the body sections in the end-to-end arrangement thereof to form therein a body structure of the hollow water heater having a portion of internal water storage container completely defined by the inner shell sections of the bonded body sections, wrapped externally by the annular isolation spaces and structurally reinforced, by means of the various integral ribs of the body section, by means of the sections of the outer shell of the body sections attached. In a preferred embodiment of the body structure of the water heater, the joining means include axially interlocked grooved portions formed on each pair of open end portions that face axially of the body sections and joining sealing them together by a welding process of induction or other acceptable joining method, such as, for example, sonic welding or friction welding. The spaces of isolation divided by the ribs within the structure of the body can remain empty, in which case the atmospheric air in them serves to thermally insulate the heated water stored inside the portion of the internal plastic container of the structure of the body. , or can be filled with an acceptable separate thermal insulation material such as an airgel material, to additionally isolate the stored water from the external heat loss.

Additionally, the water heater comprises supplying means for running water that will be heated from an external source thereto to the inside of the portion of the internal water storage container; heating means represented by at least one electrical resistance heating element, operative to heat the water disposed within the portion of the internal water storage container; and outlet means for discharging the heated water from the portion of the internal water storage vessel of the body structure. As will be readily appreciated by those skilled in the art, the principles of the present invention can also be advantageously utilized in other types of fluid storage container apparatus without integral heating means incorporated therein. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a simplified side top view of a water heater embodying the principles of the present invention; Figure 2 is an enlarged partial cross-sectional view taken along line 2-2 of Figure 1, through an integrally molded plastic storage tank portion / specially designed outer jacket of the water heater; Figure 3 is an enlarged and vertically exploded cross-sectional detail view of the storage tank / outer jacket portion of the water heater disposed generally within the circulated area "3" in Figure 1; and the Figure is a side elevational view of partial section, on a reduced scale, schematic of an axial portion of an alternative embodiment, of three sections of the water heater storage tank / structure of the outer jacket. DETAILED DESCRIPTION Referring initially to Figure 1, the present invention provides a specifically designed water heater 10, representative of an electric water heater, in which the conventionally used internal metal water storage tank is advantageously removed. The water heater 10 has a generally vertically oriented cylindrical body structure which serves as a water storage apparatus defined by two opposite, upper and lower, opposed cylindrical and hollow molded plastic sections 12a, 12b. The end sections of the body structure 12a, 12b respectively have vertically opposed open ends 14a, 14b and closed domed ends 16a, 16b and although other suitable plastic materials can be used in their construction, they are preferably molded from a material reinforced polypropylene base plastic such as that manufactured and sold under the trade name "ACC-PRO" by Amoco Performance Products Company of Alfharetta, Georgia. In forming the end structure sections of the body 12a, 12b, a structural foam molding process is preferably used to provide the resulting body sections with improved thermal insulation capacity therewith. Referring now to Figures 1-3, each terminal section of the body structure 12a, 12b has integrally formed therein along its axial length and around its closed end an inner cylindrical shell 18; a cylindrical outer shell 20 concentric and spaced outward from the inner shell 18; and a series of radially spaced circumferentially spaced reinforcing ribs 22 joining the inner and outer shells and dividing the space therebetween into arcuate insulation space segments 24. The annular grooves 26a, 26b additionally shaped respectively are molded into opposite open ends 14a, 14b of the end sections of the body structure 12a, 12b (see Figure 3) During the assembly of the molded plastic body structure, these grooves are vertically interlaced with each other to form an annular joint J between the terminal sections 12a, 12b (see Figure 1). The two terminal sections 12a, 12b are then joined to each other with the ribs 22 in each section being aligned circumferentially with the ribs 22 in the opposite section, inductively welding the two sections to each other around the annular joint J. Other methods Bonding, such as sonic or friction welding, can be used alternatively if desired. Fully molded support legs 28 are suitable with, and extend downwardly from the closed bottom end 16b of the bottom end section 12b and these may rest on a suitable horizontal support surface such as the floor 30 shown in FIG. Figure 1, to slightly raise the body structure of the water heater above the floor. To complete the assembly of the water heater 10, several generally conventional components are communicated in a suitable manner with the sealed interior 32 of the body structure of the molded plastic water heater. Specifically, as illustrated in Figure 1, these components include an inlet pipe 34 for cold water, an outlet fitting 36 for hot water and a relief valve 38 for temperature and pressure that extends through the openings suitable in the closed upper end 16a of the terminal section 12a of the molded plastic body; a pair of electric resistance heating elements 40 spaced vertically extend horizontally inward through the corresponding side wall openings in body sections 12a and 12b; and a drain pipe 42 with valve extends inwardly through the lower end 16b of the body section 12b. During the operation of the water heater 10, cold water is flowed through a pressurized source into the interior 32 of the water heater where it is heated by the electric resistance elements 40 and stored. When the plumbing fixtures with which the water heater 10 is operatively connected require hot water, the heated water, stored inside the interior 32 of the molded plastic body structure, is flowed outwardly through the pipe fitting. outlet to the pipe fittings by means of a hot water supply pipe (not shown) interconnected between the plumbing fixtures and the exit fitting 36. The hot water discharged outwardly through the fitting 36 is automatically replaced by cold water under pressure that flows down through the 12 inlet pipe 34 for heating through electrical resistance elements 40. It is important to note that in the water heater 10 described above, a main conventional component - ie, the conventional metal storage tank within which the It heats and cold water that enters under pressure is stored. Consequently, the weight, cost and corrosion problems associated with the previously required metal tank have been advantageously eliminated in the present invention. Instead of the internal metal tank removed the inner plastic walls 18 of the sections of the molded plastic body 12a, 12b define a hot water storage container which completely and sufficiently substitutes the common separated metal tank economically. Also advantageously removed in the water heater 10 representatively illustrated from the present invention are the separate insulation stages by wrapping around the outside of the metal tank and then placing the same in a separate outer metal jacket around the insulation to protect it and secure it on your site. The segments 24 of the inner shell space serve as sealed isolation chambers disposed between the inner and outer shells 18, 20 and separated by the inner ribs 22, the air within the chambers 24 serves to isolate the hot water stored inside the heater 10 against the loss of heat outside through the body structure of molded plastic water heater. This insulation effect is amplified by the structural foam molding process used to form the individual sections of the body, a process that lowers the thermal transfer rates of the resulting molded plastic structures. The ribs 22 also serve to reinforce the inner plastic tank portion of the heater 10 (defined in its entirety by the inner shells 18) by transferring the outwardly directed internal pressure forces imposed thereon to the outer shells 20 by means of the ribs 22. The outer shells 20 therefore do not only partially define the space of outer insulation surrounding the inner shells 18, but also serve as load bearing structures of the water pressure. As illustrated in Figure 1 the water heater 10 shown has two molded plastic cylindrical body sections 12a and 12b joined in the end-to-end manner as previously described, with both body sections being "terminal" body sections or axially external that have closed axial external ends. If desired, however, the axial length of the body structure of the water heater can be increased by interposing one or more cylindrical intermediate body sections 12c (each having two open ends) between the terminal sections 12a, 12b of the structure. of the body previously described to form the alternative embodiment 10a of the water heater shown in Figure 4. In such an alternative 10a water heater embodiment (in which the various pipe and heating elements have been removed for greater illustrative clarity) each one of the open ends of each of the sections 12 of the molded plastic body is welded by induction, or secured by otherwise sealing, the opposite open end of the. next axial segment of the structure of the general body in the joint J. As 'previously described, the segments 24 of the insulation space between the shells can simply be left empty to allow air at atmospheric pressure therein to serve as a means of isolation. Alternatively, as illustrated in Figure 4, these segments of the insulation space 24 can be appropriately filled with additional insulation such as the foam insulation material 44 injected illustrated.

The foregoing description should be clearly understood as a form of illustration and example of the present invention only, the spirit and scope of the present invention being limited only by the appended claims.

Claims (20)

1. CLAIMS 1. A water storage apparatus characterized in that it comprises: a plurality of hollow tubular body sections of a molded plastic piece placed in an end-to-end coaxial orientation and including a first and a second end section opposite having closed outer ends, each of the body sections having: (i) a tubular inner shell section, (ii) a tubular outer shell section circumscribing coaxially to the internal tubular shell section and forming between the sections of inner and outer shell an annular isolation space, and (iii) a series of circumferentially spaced ribs extending radially through the annular isolation space and dividing it into circumferential segments, the ribs being integrally molded with the sections of inner and outer shell, with each of the closed outer ends of the first and second s opposite terminal sections molded integrally with the balance of their associated external terminal section; and joining means for joining by sealing the open end portions of each axially adjacent pair of the plurality of body sections to form a hollow water storage body structure having a swine from the plurality of the body sections. of internal water storage container completely defined by the inner shell sections, wrapped externally by annular isolation spaces and structurally reinforced, by means of the ribs, through the outer shell sections. The water storage apparatus according to claim 1, characterized in that: the plurality of body sections includes only the first and second opposite end sections. The water storage apparatus according to claim 1, characterized in that the plurality of body sections includes the first and second opposite end sections and at least one additional body section interposed coaxially therebetween. 4. The water storage apparatus according to claim 1, characterized in that the joining means include: an induction weld at the opposite open end portions of each axially adjacent pair of the plurality of body sections. The water storage apparatus according to claim 1, characterized in that: the ring insulation space segments are empty. The water storage apparatus according to claim 1, characterized in that: the annular insulation space segments are filled with a thermal insulation material. The water storage apparatus according to claim 1, characterized in that: the plurality of sections of the body are made of a reinforced polypropylene base plastic material. The water storage apparatus according to claim 1, characterized in that: the plurality of the body sections are plastic molds of structural foam. The water storage apparatus according to claim 1, characterized in that: each pair of axially opposite open end portions of the plurality of body sections have annular, axially slotted portions between loops. 10. The water storage apparatus according to claim 1, wherein the water storage apparatus is a water heater characterized in that it additionally comprises: supply means associated with the structure of the body, to cause the water flowing to flow will heat from an external supply source into the interior water storage container portion, heating means operative to heat the water disposed within the portion of the internal water storage container, and outlet means associated with the body structure, for discharging the heated water from the portion of the internal water storage vessel of the body structure. The water heater according to claim 10, characterized in that the heating means include: at least one heating element of electrical resistance type that extends within the portion of the internal water storage vessel of the structure of the body. 12. A method for manufacturing the water storage apparatus characterized by the steps of: providing a plurality of sections of hollow molded plastic tubular tube sections including a first and a second end section opposite, each section having of the body a tubular inner shell section, a tubular outer shell section circumscribing coaxially to the internal tubular shell section and forming between the inner and outer shell sections an annular isolation space, and a series of ribs spaced circumferentially it extends radially through the annular isolation space and divides it into circumferential segments, the ribs being integrally molded with the inner and outer shell sections, and each of the closed outer ends of the first and second opposite end sections being being integrally molded with the balance of your section n associated outside terminal; the positioning of the plurality of body sections in an end-to-end coaxial arrangement with the ends of the outer body section closed axially outwardly at opposite ends of said arrangement; and joining by sealing the opposite open end portions of each axially adjacent pair of the plurality of the body sections to form from the plurality of the body sections a hollow water storage body structure having a container portion of internal water storage completely defined by the inner shell sections, wrapped externally by annular insulation spaces and reinforced structurally, by means of the ribs, through the outer shell sections. The method according to claim 12, characterized in that: the supply step is performed by providing only the first and second opposite end sections. The method according to claim 12, characterized in that: the supplying step is performed by providing the first and second opposite end sections and at least one additional body section interposed coaxially therebetween. The method according to claim 12, characterized in that: the joining step includes the step of inductively welding the opposite open end portions of each axially adjacent pair of the plurality of body sections. 16. The method according to claim 12, characterized in that the joining step includes the steps of: 2] the groove forming axially inwardly annular in each axially opposite pair of the open end portions of the plurality of body sections, and the axial interlacing of each opposite pair of the open end portions using the grooves thereof. The method according to claim 12, characterized in that it additionally comprises the step of: filling the segments of the annular insulation space with a thermal insulation material. 18. The method according to claim 12, characterized in that: the supply step is performed by molding the plurality of body sections from a reinforced polypropylene base plastic material. The method according to claim 12, characterized in that: the step of supplying includes the step of forming the plurality of sections of the body using a plastic molding process of structural foam. The method according to claim 12, characterized in that it additionally comprises the steps of: the operative association of the supply means of the body structure to cause the water to be heated to flow from an external supply source into the interior of the portion of the inner water storage container, operatively extending at least one water heating element of electrical resistance type within the inner water storage container portion of the body structure, and the operative association with the means for exiting the body structure to discharge the heated water from the portion of the internal water storage vessel of the body structure. SUMMARY OF THE INVENTION The present invention relates to a water heater having a body structure formed in a manner that eliminates the need for a separate metal storage tank therein. The body structure is formed by a series of coaxially sealed and sealed one-piece molded plastic body sections that include opposite end sections having closed outer ends. Each of the one-piece molded plastic body sections has inner and outer shell portions which are coaxial with each other and radially spaced apart by a series of circumferentially spaced radially extending ribs molded integrally therewith and defining between them a series of arcuate insulation spaces that extend circumferentially. In the structure of the assembled body the inner shell portions completely define in the water heater a portion of internal water storage vessel that is wrapped externally by the insulation spaces and structurally reinforced, by means of the integral ribs, through the outer shell sections. The appropriate inlet and outlet piping is operatively communicated with the interior of the body structure and the water disposed in the portion of the internal storage container thereof can be selectively heated by one or more electrical resistance type heating elements operatively mounted in The body structure of the water heater.