IL203630A - Modular hot water storage tank - Google Patents

Description

Modular hot water storage tank 203630/2 FIELD OF THE INVENTION The present invention relates to a water heater. More particularly, the invention provides a water heating system including a modular storage tank.

BACKGROUND OF THE INVENTION Water heater systems comprise a hot water storage tank for maintaining a constant reservoir of hot water. In order to increase the volume of hot water that may be stored, different sized storage tanks may be employed. Consequently, if it is desired to increase the volumetric capacity of a water system, the complete water storage tank must be replaced by one of larger capacity. This is expensive.

Attempts appear to have been made in the prior art to provide a modular heating tank. For example, WO 2008/043343 describes a system comprising a modular-type heating device and method for replacing a module of the heating device. The heating device is particularly adapted for use in a motor vehicle and comprises at least one first module that can be coupled to a second module of a first type by a common interface. The first module can also be coupled to a second module of a second type that is different from the first type, via the common interface. The invention also relates to a method for replacing a module of a modular-type heating device.

In such a construction for use in motor vehicles, the volume of each module is fairly small and where the modules may be rigidly attached to the vehicle chassis. But such a modular construction is not applicable to water heating systems where each storage module must be configured to store more than 100 liters of water, and where the storage tanks are typically free-standing, since large volume tanks are subject to reduced rigidity, thus requiring some external means to secure them to a fixed structure.

DE 102004005829 discloses a hot water tank with a screw-plastic container having at least two container parts interconnected by flanges. There is no suggestion to provide a modular tank formed of multiple container parts.

JP2005 172354 A2 describes a module slruclure of electric instantaneous water heater capable of being installed in a compact space even when a heater module is additionally mounted, and which is as easily controlled as a single water heater tank. To this end, there is provided a water supply module constituted by a feed water module mounted at a side of a water supply pipe. A heater module includes means for heating the supplied water and a hot water supply module serves as a hot water outlet installed on a side of a hot water supply pipe. The modules are respectively detachably connected by the water supply pipe and the hot water supply pipe. The number of heater modules mounted between the water supply module and the hot water supply module is adjustable, so as to increase both the thermal and volumetric capacity of the tank.

In such a construction, supply pipes protruding from opposite ends of the heater modules must be interconnected such that when multiple heater modules are provided, they are connected in parallel , Moreover each heater module includes not only its own heater but also thermostatic controller, which operates in conjunction with a flow rate controller in the feed water module coupled to a proportional valve so as to adj ust water flow rate so that the water is heated to the required target temperature in the heater modules. This means that when it is required to increase the capacity of the water storage tank, the pipes of adjacent heater modules must be coupled and suitable electrical connection must be made to each of the thermostatic controllers. It is apparent from Figs. 5 and 6 of JP2005172354 that the water tank is intended for use with central heating systems and it emerges from the description that the modules are interconnected only by virtue of their respective inlet and outlet flanges being coupled to common cold and hot water supply trunks. In other words, the disclosure allows for the hot water storage capacity to be increased by coupled a number of separate and independent modules in parallel across the inlet and outlet lines.

As opposed to conventional hot water storage tanks for central heating systems of the kind described where the water is heating inside the water lank, it is also known to heat the water externally. For example, U.S. Patent No. 5,203,500 (Home) and U.S. Patent No. 2,016,746 (Ireland) disclose hot water supply systems comprising a hot water storage tank positioned within a building and an external gas-fueled burner positioned outside the building adjacent a heat exchanger which is connected in fluid communication with the indoor water storage tank for indirect heating thereof.

U.S. Patent No. 6,283,067 (Akkala) discloses a water temperature management system that includes an auxiliary energy transfer system for heating water in a tank when the water in the tank falls below a selected minimum temperature.

U.S. Patent No. 6,612,268 (Peteri) discloses a small capacity water heater for operationally interconnecting with a hot water storage tank.

IL 176460 equivalent lo US 2008/0041363 in the name of the present Applicant discloses a water heater for operationally interconnecting with a hot water storage tank in a Ihermosyphonic solar water heating and storage system, where the water heater is external lo the main storage tank.

In such arrangements, there is no intrinsic need for a heater module in the main water storage tank, since the water is indirectly heated either by the sun in a solar heating system or by a furnace as in U.S. Pat. No. 5,203,500 or U.S. Pat. No. 2,016,746. The parallel connection of healer modules provided by JP2005172354 is not suitable when the heater modules are Ihe primary source of heat, but they are wasteful for a solar water healing system since parallel heating of the water in adjacent tanks means that the complete volume of water in each tank is heated. Moreover, the need to connect the heaters militates against the simple interconnection of such modules to form a modular tank of unitary construction.

It would therefore be desirable to provide a modular water storage lank that is better suited for use with waler healing systems where water is heated external to the water storage tank and which can be coupled in series rather than parallel.

SUMMARY OF THE INVENTION It is therefore one of the objects of the present invention to provide a modular water storage tank that is better suited for use with water heating systems where water is heated external to the water storage tank and which can be coupled in series ralher than parallel.

It is a further object to provide a modular water storage tank where adjacent modules can be interconnected without the need for interconnecting pipe joints.

The present invention achieves the above objects by providing a water storage module for use with a water heating system where water is heated external to a modular water storage tank comprising at least two interconnected water storage modules, wherein a mating edge of each waler storage module is of circular cross-section and - 4 - 203630/2 supports an outwardly projecting flange that serves to increases rigidity of the module and around which are provided holes for connecting adjacent water storage modules in series.

The water storage modules include an end module that is sealed at one end and which may be coupled at an opposite open end either to another end module or to one or more intermediate modules, which are typically of uniform cross-section. They may also be of uniform dimensions or, alternatively, different intermediate modules may have different capacities so that a unitary water storage tank may be formed of desired capacity merely by end-to-end coupling of different modules. However, it is envisaged that most typically a manufacturer will produce only two different types of module, i.e. an end module and an intermediate module of identical cross-section at their respective mating ends. In use, either two end modules are directly coupled via a sealing gasket or are coupled via one or more intermediate modules so as to produce a storage tank of required capacity.

Since the water storage tank must be sealed at each extremity, the end modules are typically in the form of a hemispherical dome having a flange at an open end. The water storage tank is formed by coupling at least two such end modules, which are also provided with water inlet and outlet fittings. Alternatively, a water storage tank of higher capacity can be formed by interconnecting between the end modules a desired number of intermediate modules having flanges at both ends. The intermediate modules generally do not require water inlet and outlet fittings, so that the formation of a modular storage tank of desired capacity is rendered very simple and trouble-free, while requiring the distributor and the technician to maintain a stock of only two different types of module.

The modular water storage tank according to the present invention is suitable for use in a solar thermosyphonic water heating and storage system such as described in above-mentioned US 2008/0041363. However, it is also suitable for heating systems of the kind described in the above-referenced patents, which are neither solar nor thermosyphonic.

BRIEF DESCRIPTION OF THE DRAWINGS In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: FIG. 1 is a schematic cross-sectional view of an end module for a water storage tank according to the present invention; FIG. 2 is a schematic cross-sect ional view of an intermediate module for a water storage tank according to the present invention; and FIG. 3 is a schematic cross-sectional view of a modular water storage tank according to a first embodiment; FIG. 4 is a schematic cross-sectional view of a modular water storage lank according to a second embodiment mounted vertically; and FIG. 5 is a schematic cross-sectional view of the modular water storage tank according to the second embodiment mounted horizontally.

With specific reference now to the figures in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made lo show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

DETAILED DESCRIPTION OF EMBODIMENTS In the following description of some embodiments, identical components that appear in more than one figure or that share similar functionality will be referenced by identical reference symbols.

It should also be noted that heating system where water is pre-heated prior to feeding to a hot water storage tank are well known per se and so are not described in detail. They are well described in above-mentioned US 2008/0041363 as well as the other references mentioned above, all of whose contents are incorporated by reference.

FIGS. I and 2 show respectively an end module 11 of generally hemispherical shape and an intermediate module 12 each having an open end of circular cross-section that supports an outwardly projecting flange 13 that serves to increase rigidity of the module and around which are provided holes 14 for connecting adjacent water storage modules in series.

The end module 11 includes a first connection point 15 that is disposed at the crest of the dome and a second connection point 16 that is disposed intermediate the top of the dome and the flange, i.e. at an angle of approximately 45° to the vertical. Likewise, the intermediate module 12 may optionally be provided in a side wall thereof with first and second connection points 17 and 18, for reasons that will be explained below.

FIG. 3 is a schematic cross-sectional view of a modular water storage tank 20 according to a first embodiment comprising a pair of end modules I I and I V mounted back-to-back and interconnected via a gasket 21 that provides a fluid-tight seal. The adjoining modules may be fastened using bolts (not shown) that are passed through the holes 14 around the flanges 13 and then secured using a nut. If desired, the flanges 13 and the holes 14 may serve to support the storage tank. For example, the lower flange may rest on the rim of a recessed support structure; or may be supported by legs on a floor surface or even suspended from an overhead structure and secured to the bolts that interconnect adjoining modules. Such a structure is intrinsically rigid owing to the hemispherical shape of the modules. The modular storage tank 20 has a total of four connection points, namely the first and second connection points 15 and 16 in the upper module 1 and third and fourth connection points 15' and 16' in the upper module 1 . The first connection point 15 is at the crest of the upper module 1 1 serves to couple to the hot water outlet in a conventional hot water system. The second connection point 6 in the upper module 1 1 serves as a hot water inlet, to which hot water is fed from an external heater. The third connection point 1.5' in the lower module 1 serves as a cold water inlet to which cold water is fed from the main water feed supply. The fourth connection point 16' in the lower module 1 1' serves as a cold water outlet which feeds cold/warm water from the tank to a cold water inlet of the external heater. The external heater may be a solar panel coupled to the storage tank in conventional manner or via an auxiliary storage tank as described in US 2008/0041363. The manner in which water is heated and fed to the storage tank is not itself a feature of the present invention.

FIG. 4 is a schematic cross-sectional view of a modular water storage tank 25 according to a second embodiment comprising a pair of end modules 1 1 and I mounted back-to-back and interconnected via at least one intermediate module 12 using respective gaskets 21 so as to provide a water-tight seal. As noted above, there may optionally be provided in a side wall of the intermediate module 12 with first and second connection points 17 and 18. These may be coupled to a heat exchanger (not shown) mounted inside the module 12, for example in the form of a spiral tube through which very hot water is fed from a furnace or solar heater and which serves to heat water in the intermediate module 12 in what is known as an indirect heating system. Such arrangements are well-known per se and are described in above-mentioned U.S. Patent Nos. 5,203,500 and 2,016,746, to which the reader may refer for a more detailed description. In such case, the heat exchanger may be retro-fitted to the intermediate module or a customized intermediate module may be provided having the heat exchanger already connected. However, the intermediate module may be used only to increase the capacity of the water storage tank 25, in which case when the water tank 25 is mounted vertically as shown in FIG. 4 the connection points 17 and 18 are not necessary or, if provided, may be closed off or sealed.

FIG. 5 is a schematic cross-sectional view of the modular water storage lank 25 mounted horizontally. In this case, the tank is oriented so that connection points 17 and 18 are at the lop of the tank, and one of these feed points serves as the hot water outlet, since it is preferable that the hot water outlet be disposed at the highest point of the lank. The other, if provided, may be closed off or sealed.

It will thus be appreciated that by judicious use of a pair of end modules and an appropriate number of intermediate modules, different configurations and capacities of hot water storage tank may be constructed according to required capacity and type of installation. Moreover, substantially any kind of installation can be realized using only these Iwo modules so that a technician need carry only these modules in stock lo meet the requirements of the end-user. Likewise, if it be required lo increase the capacity of an existing installation, all that need be is to drain the water from the hot water tank, disconnect one of the end modules and then fit a required number of intermediate modules prior to re-fitting the disconnected end module. The same applies in the event of damage to one of the modules, which can be replaced without the need to replace the remaining functional modules.

The modules may be formed of any suitable material. Thus, they may be formed of conventional materials such as metal. However, in this case, it is necessary in use to wrap insulating material around outer surface of the tank in order to reduce thermal losses. This requirement is avoided by forming the modules of molded plastics formed using centrifugal or injection molding techniques. Moreover, the use of plastics avoids problems of rust that are inevitable with metal tanks and invariably require that they be replaced periodically. When the modules are formed of plastics, it may be necessary, depending on the capacity of the intermediate module, to provide additional reinforcement in which case ribbing may be provided. This may be by way of metal or plastic hoops surrounding the side wall of the module or, if the module is formed of plastics, by way of circumferential plastic ribbings integrally molded within the side wall of the module either internally or externally.

It will be appreciated that the dimensions of the modules is not a feature of the invention, so long as modules of the required capacity can be manufactured at sufficient strength. By way of non-limiting example, it is noted that an intermediate module having of circular cross-section having a diameter of 50 cm and a height of 20 cm has a volume of nearly 40 liters. Typically, hot water storage tanks have capacities in the range of 150-250 liters, so the incremental volume of 40 liters afforded by a single intermediate module represents a welcome and significant increase, and saves the need to replace the complete tank.

It will also be appreciated that the location of the connection points 15, 16, 17 and 18 is not critical. It is, of course, highly desirable that the assembled tank have a cold water inlet at or toward its lowest extremity and a hot water outlet at or toward its uppermost extremity. The location of the other connection points is less critical. It will also be understood that if the modules are formed of plastic moldings, the connection points can easily be drilled in situ, in which case the modules may even be manufactured and sold without the connection points being pre-formed. This saves the need to plug any connection points that are not used.

It will be evident to those skilled in the art that the invention may be embodied in other specific forms without departing from the essential attributes thereof, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (11)

- 9 - 203630/2 CLAIMS:

1. A water storage module for use with a water heating system where water is heated external to a modular water storage tank comprising at least three interconnected water storage modules, wherein a mating edge of each water storage module is of circular cross-section and supports an outwardly projecting flange that serves to increase rigidity of the module and around which are provided holes for connecting adjacent water storage modules in series.

2. The water storage module according to claim 1 being a hemispherical dome having a first connection point disposed at a crest of the dome and a second connection point disposed intermediate the crest of the dome and the flange.

3. The water storage module according to claim 1 being cylindrical.

4. The water storage module according to claim 3 being provided in a side wall thereof with a first connection point and a second connection point.

5. The water storage module according to claim 4 containing a heat exchanger coupled to the first and second connection points.

6. The water storage module according to any one of claims 1 to 5, being formed of metal.

7. The water storage module according to any one of claims 1 to 5, being formed of injection molded plastics.

8. The water storage module according to claim 3, being reinforced with circumferential ribbing.

9. The water storage module according to claim 8, wherein the circumferential ribbing comprises metal or plastic hoops surrounding a side wall of the module.

10. The water storage module according to claim 8, being formed of injection molded plastics and wherein the ribbing is integrally molded within the side wa

11. ll.