FIELD OF THE DISCLOSURE

The present invention relates to a vessel, a water heater system, and method of manufacture.

BACKGROUND

Tanks for water heaters are traditionally cylindrical in shape, hence the colloquial name of "hot water cylinder". This shape is primarily due to ease of manufacture. However, this has a number of inherent disadvantages. For example, the shape necessitates custom assembly of pipework and valves in order to connect to the various fittings associated with the cylinder and water inlets/outlets. This adds to the labour component of installation - both in terms of designing and obtaining the necessary components, and also assembling and connecting those components.

Further, there are also challenges in securing a cylinder in place, particularly to resist movement during seismic events. Due to its shape, a cylinder has minimal surface area in contact with supporting walls against which it is positioned - allowing rolling of the cylinder if there is sufficient flexure in restraints applied around it.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice. All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

Throughout this specification, the word "comprise" or "include", or variations thereof such as "comprises", "includes", "comprising" or "including" will be understood to imply the inclusion of a stated element, integer or step, or group of elements integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

SUMMARY According to an exemplary embodiment of the present disclosure there is provided a vessel including: a body having a filament wound watertight side wall, wherein the cross-sectional shape of the vessel through the side wall is substantially that of a square with convex sides. It is envisaged that the vessel may have particular use in water heater systems, and may be referred to herein as being a water vessel.

Reference to a square with convex sides should be understood to mean a shape approximating a square - i.e. a regular four sided shape - but with its sides made up of four outwardly curved arcs of even length and curvature. In an exemplary embodiment the cross-sectional shape of the vessel may be substantially a superellipse with convex sides. A superellipse with convex sides should be understood to mean a geometric figure defined in the Cartesian coordinate system as the set of all points (x, y) with

\ ^x \ ^r \V\ ^r where r, a and b are positive numbers; and r > 1 and not equal to 2. In an exemplary embodiment the superellipse may be such that 1 < r < 2.

The curvature is envisaged as providing greater wall strength than a completely square shape by reducing stress concentration - while still producing a shape having a greater volume than an entirely round tank of the same width.

Reference to filament winding should be understood to mean a fabrication technique whereby a strand of fibrous material is wound about a form provider (for example a frame, mandrel or male mould) in a number of superimposed layers. The filament may be impregnated with a resin, whether at the time of winding, or as supplied from a manufacturer.

Filament winding of watertight walls of the vessel is envisaged as enabling manufacture of this shape in a cost effective manner while achieving requisite strength characteristics and also maintaining a sufficiently low weight for transportation and installation. The outward curvature of the sides of the vessel may assist in maintaining tension on the filament during winding, thereby pressing the filaments tightly against each other to reduce the likelihood of voids. In an exemplary embodiment the side wall may include a plurality of layers of filament windings. It should be appreciated that the filament winding and/or layers may be wound on in a range of orientations using any suitable winding techniques known in the art.

According to an exemplary embodiment of the present disclosure there is provided a method of manufacturing a vessel, including: providing an elongate form provider having a cross-sectional shape being substantially that of a square with convex sides; controlling rotation of the form provider in combination with travel of a carriage from which filament is distributed, to produce at least one layer of filament surrounding the form provider to produce a waterproof side wall of the vessel. Reference to a carriage should be understood to mean a device configured to move relative to the form provider to guide the position of the filament on the form provider. It should be appreciated that the form provider and carriage are components of a filament winding machine - which depending on the filament winding technique used may include other components such as filament spool reels, tensioners, and resin baths. In an exemplary embodiment, rotation of the form provider and travel of the carriage may be controlled by a controller including at least one processor.

It is envisaged that the side walls of multiple vessels may be manufactured on the same form provider. It is envisaged this may assist with manufacturing efficiencies - with the curing time of the filament/resin before the side walls may be removed being a significant time component of the overall manufacturing process.

In an exemplary embodiment the vessel may include an end cap at each end of the continuous side wall to enclose an interior space of the vessel.

In an exemplary embodiment at least one end cap may be made as a separate part and secured to the side wall. For example, the end cap may be manufactured using filament winding or a spray lay-up process (being a technique whereby resin and reinforcements are sprayed onto a surface - for example a "chopper gun"). While the end cap may be manufactured using other materials and manufacturing techniques (for example, injection molding), it is envisaged that manufacture of the end cap using similar materials to the side wall may reduce the likelihood of failure at the interface between the side wall and end cap due to differences in material properties. In an exemplary embodiment, the end cap may include an end plate having a wall extending therefrom, the wall configured to fit into, or over, the side wall to create an overlap. The end cap may be secured to the side wall using any suitable technique - but it is envisaged that a spray lay-up layer may assist in achieving a watertight seal . An adhesive, such as a resin, may be applied at the interface between the side wall and the wall of the end cap. In an exemplary embodiment at least one end cap may be formed in place on the side wall. For example, an end of a mandrel on which the side wall is manufactured may be shaped to suit the end cap. The end cap may be formed on the end of the mandrel - for example by filament winding, or a spray lay-up process.

In an exemplary embodiment the vessel may include at least one hoop around an exterior surface of the side wall, restricting bowing of the side wall. It is envisaged that the vessel may include a plurality of hoops spaced apart along the side wall.

It should be appreciated that reference to a hoop is not intended to be limiting to a circular shaped member, as it is envisaged that the interior shape of the hoop may approximate the exterior cross-section of the water vessel. In an exemplary embodiment the hoop may have a wall width greater that its thickness.

Reference to a wall width should be understood to mean the dimension of the hoop in a direction perpendicular to the side wall of the vessel - i.e. radial thickness of the hoop. By way of illustration, a flat washer may be seen as an exaggerated version of the structure of the hoop in such an embodiment. By way of example, the interior surface of the hoop contacting the vessel may be in the order of 3 mm thick, while the height of the hoop in a direction

perpendicular to the vessel (i.e. thickness) may be in the order of 20 mm.

The hoop(s) may be made of any suitable material having - for example aluminium, iron, stainless steel, or a plastics material.

In exemplary embodiments, the vessel may take the shape of a polyhedron. Reference to a polyhedron should be understood to mean a three dimensional shape having flat faces meeting at vertices (although it should be appreciated that such corners or edges may be rounded without). It should be appreciated that the filament wound walls may not form every face of the vessel - for example, the side walls may be filament wound, with one or more of the ends a plate.

In particular, the vessel may be substantially cuboid. Such a shape may have numerous benefits in the context of water heating systems. For example, such a shape may enable a water heater to be positioned with a substantial surface area against a wall, or in a corner. In comparison with a standard cylindrical water heater, such an arrangement may naturally restricts movement of the water heater (particularly during a seismic event), making securing of the vessel more straightforward. Further, it may assist in the connection of pipe work and various other components associated with a water heating system, as will be discussed further below. According to an exemplary embodiment of the present invention there is provided a vessel including: filament wound watertight walls, wherein the vessel is substantially cuboid .

According to an exemplary embodiment of the present invention there is provided a method of manufacturing a water vessel for a water heating system, the method including: filament winding watertight walls about a cuboid structure.

In an embodiment, at least one support bracket may be attached to the vessel. It is envisaged that the support bracket may be used to secure the water vessel and/or water heater system including the vessel to a support such as one or more walls - whether directly or indirectly through intermediary connectors. For example, the support bracket may be filament wound to the walls of the vessel. Doing so may assist in ensuring that weight of the vessel and water contained therein are transferred through the support bracket to the wall to which it is secured.

According to an exemplary embodiment of the present invention there is provided a vessel including: an open sided frame; and watertight walls filament wound around at least the open sides of the frame.

Reference to an open sided frame should be understood to mean framework forming the skeleton of the vessel. I n embodiments, the frame may include support plates in portions to provide reinforcing for fittings to be attached to the vessel. However, by generally making the frame open sided, and relying on the water tightness of the filament wound walls, it is envisaged that weight and material cost savings may be made. Being on the interior of the filament wound walls, preferably the frame may be made of corrosion resistant material.

For example, the frame may be made of stainless steel - which in addition to having relatively high resistance to corrosion also has strength properties which are useful during the manufacturing process and also reinforcement of the vessel in use. However, it should be appreciated that this is not intended to be limiting, and other material may be used to provide structure for the frame.

According to another exemplary embodiment, there is provided a kitset for a water heater system, including : a water vessel; a pre-assembled valve assembly adapted for attachment to the water vessel, including: a cold water expansion valve; a non-return valve between the cold water expansion valve and an inlet for connection to a cold water source; an isolation valve between the cold water expansion valve and the inlet for connection to the cold water source; and a tempering valve between the water vessel and a hot water outlet from the assembly.

According to another exemplary embodiment, there is provided a method of installing a water heater system substantially as previously described, including the steps of: connecting the pre-assembled valve assembly to the water vessel; and connecting the pre-assembled valve assembly to a cold water source and a hot water distribution line.

According to another exemplary embodiment, there is provided a water heater system, including: a water vessel; a valve assembly to the water vessel, including: a cold water expansion valve; a non-return valve between the cold water expansion valve and an inlet for connection to a cold water source; an isolation valve between the cold water expansion valve and the inlet for connection to the cold water source; and a tempering valve between the water vessel and a hot water outlet from the assembly.

Reference to a pre-assembled valve assembly should be understood to mean a collection of valves interconnected in a required configuration for desired or regulated operation of a water heating system, to be connected to the water vessel, and plumbing fittings such as a cold water source, hot water distribution line, and drain. It should be appreciated that the valve assembly may include pipework and/or a pipe manifold for interconnection of the valves and inlet/outlet of the water vessel. Such components may be referred to as services of a water heating system.

Typically, installers of water heater systems are required to purchase the requisite components separately, to be assembled with customised piping for the particular installation on the job - the specific positioning and pipework being heavily influenced by the curved shape of typical water heaters.

In exemplary embodiments of the present invention, particularly those with a cuboid shape, the pipework is uniform, enabling the valve assembly to be supplied pre-assembled and sealed - significantly reducing labour requirements from the installer.

In exemplary embodiments a tempering valve may be provided between the water vessel and a hot water outlet from the system, configured to mix hot and cold water such that water delivered from the system does not exceed a predetermined temperature.

In exemplary embodiments a non-return valve may be provided at a cold water inlet from a source of cold water to the valve assembly, configured to prevent backflow of water into the water source.

In exemplary embodiments a cold water expansion valve may be positioned between the water vessel and the non-return valve. It may be configured to open to a drain in order to relieve increased pressure caused by water expanding in the water vessel during heating. In exemplary embodiments at least one isolation or stop valve may be provided enabling isolation of the portions of the valve assembly. For example, it is envisaged that the assembly may include a stop valve between a cold water inlet and cold water expansion valve, and a stop valve at a cold water inlet of the water vessel.

In exemplary embodiments a pressure restricting valve may be provided between a cold water inlet to the assembly and a cold water expansion valve. It should be appreciated that the pressure restricting valve may be a pressure limiting valve or pressure reducing valve as known in the art.

In exemplary embodiments a temperature and pressure relief valve may be positioned between the water vessel and a drain. It may be configured to open in response to overpressure - whether due to expansion via heating or overfilling. The temperature and pressure relief valve may not be included in the pre-assembled valve assembly. For example, the pressure relief valve may be positioned substantially towards the top of the water vessel in order to meet regulatory requirements. As a more particular example, the connection between the pressure relief valve and the water vessel may be within 150 mm from the top of the water vessel and within the top 20% of the water capacity of the vessel. It should be appreciated that the functions of one or more of the valves described herein may be provided in a single valve body. For example, so called pressure limiting stop valves may provide a combination of pressure restricting, isolation, non-return and filtering functionality.

Exemplary embodiments of the water heater system may include an outer shell within which the water vessel may be positioned. This shell may be manufactured using any suitable manufacturing technique, although it is envisaged that the shell may be manufactured using filament winding for manufacturing efficiencies.

It is envisaged that at least a portion of pipework between the water vessel and one or more points of connection to the valve assembly may be positioned between the vessel and the shell. Insulation may be positioned between the vessel and the shell to assist in retaining heat and thereby improve energy efficiency, as known in the art.

In doing so, it is envisaged that this may reduce labour on behalf of installers by eliminating the need to size and connect this pipework at the time of installation. Further, the length of pipework may be reduced (not needing to pass the distance beyond the shell). Because the pipework is contained within the shell ease of transportation may be improved, and a more aesthetically pleasing appearance provided - uninterrupted by external pipework. It should be appreciated that any valves not forming part of the preassembled valve assembly may also be positioned between the vessel and the shell for at least the same reasons.

In an exemplary embodiment, the water heater system may include insulating material between the vessel and the outer shell.

According to another exemplary embodiment, there is provided a water heater system, including: a water vessel having a first end and a second end, wherein the water vessel includes a hot water outlet located proximate the first end, and a cold water inlet proximate the second end; an outer shell within which the water vessel is positioned, with a gap between an exterior of the water vessel and an interior of the outer shell; insulating material within the gap; and services connected to at least the hot water outlet, wherein at least a portion of the services run within the gap.

It is envisaged that the positioning of pipework between the vessel and shell may be particularly applicable in embodiments in which the water vessel is mounted to a wall, and the valve assembly may be positioned beneath the vessel. Connections to and from the water vessel may all be positioned or directed towards the space beneath the vessel, further reducing the footprint of the water heater system.

In an exemplary embodiment, the outer shell may be substantially cuboid. In an exemplary embodiment the cross-sectional shape of the outer shell may be substantially square. It is envisaged that in exemplary embodiments in which the cross-section of the vessel is substantially in the shape of a squircle, the shell may present flat exterior surfaces for the water heater system as a whole.

Because the shell has at least one flat side due to its construction, this lends itself to ease of mounting securely on a wall - for example using nesting Z brackets.

It should be appreciated that the system may include other components such as a heat source, temperature sensor, and temperature controller, as well known by those skilled in the art of water heating systems.

For a firmware and/or software (also known as a computer program) implementation, the techniques of the present disclosure may be implemented as instructions (for example, procedures, functions, and so on) that perform the functions described. It should be

appreciated that the present disclosure is not described with reference to any particular programming languages, and that a variety of programming languages could be used to implement the present invention. The firmware and/or software codes may be stored in a memory, or embodied in any other processor readable medium, and executed by a processor or processors. The memory may be implemented within the processor or external to the processor.

A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a digital signal processor (DSP) and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The processors may function in conjunction with servers and network connections as known in the art.

The steps of a method, process, or algorithm described in connection with the present disclosure may be embodied directly in hardware, in a software module executed by one or more processors, or in a combination of the two. The various steps or acts in a method or process may be performed in the order shown, or may be performed in another order.

Additionally, one or more process or method steps may be omitted or one or more process or method steps may be added to the methods and processes. An additional step, block, or action may be added in the beginning, end, or intervening existing elements of the methods and processes.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of an exemplary frame for use in manufacturing a vessel according to an exemplary embodiment of the invention;

FIG. 2 is a perspective view of an exemplary vessel according to an exemplary

embodiment of the invention;

FIG. 3 is a perspective view of an exemplary method for securing the water heater

system;

FIG. 4 is a perspective view of another exemplary water heater system according to an exemplary embodiment of the invention; FIG. 5A is a perspective view of an exemplary method for securing the water heater system;

FIG. 5B is a side view exemplary mounting system for use in the method of securing the water heater; FIG. 6A is a perspective view of another exemplary vessel according to an exemplary embodiment of the invention;

FIG. 6B is a cross-sectional view of the exemplary vessel;

FIG. 6C is a cross-sectional view of a water heater including the exemplary vessel;

FIG. 7A is a plan view of an exemplary filament winding machine for manufacture of an exemplary vessel according to an exemplary embodiment of the invention;

FIG. 7B is a side view of an exemplary mandrel for use with the exemplary filament

winding machine;

FIG. 8A is an exploded side view of the exemplary vessel, and

FIG. 8B is a longitudinal cross-sectional view of an end of the exemplary vessel.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary open sided frame 1 for use in manufacturing a water vessel for a water heater.

The frame 1 is cuboid in shape, including elongate frame members 2 in the form of quarter round stainless steel forming the edges of the frame 1.

A first stainless steel support plate 3 is welded across the top of one side of the frame 1 , having sockets 4 and 5 defining apertures between the interior and exterior of the frame 1. Similarly, a second stainless steel support plate 6 is welded across the bottom of the same side of the frame 1 , having a socket 7 defining an aperture between the interior and exterior of the frame 1 , and also mounting aperture 8 through which a water heater element (not illustrated) may be passed and subsequently mounted.

A stainless steel base plate 9 is welded to one end of the frame 1. The base 9 may include a stem (not illustrated) which is held by a winding apparatus (not illustrated) for rotation during filament winding. Resin impregnated filaments are wound around the frame 1 to create filament wound walls (illustrated in part by wall 10).

Sockets 4, 5, and 7 project into the frame 1 rather than outwardly, for ease of filament winding, and are drilled out once the resin has set. Male and female extensions may be added for connection to the exterior at this point.

The resulting water vessel 1 1 may be seen in FIG. 2, which illustrates a floor mounted water heater system 20.

A cold water inlet 21 from a cold water source is connected to a pressure limiting stop valve 22, which is in turn connected to a cold water expansion valve 23. An angle isolation valve 24 connects the cold water expansion valve 23 to the cold water inlet 25 of the vessel 1 1.

A tempering valve 26 connects between the cold water expansion valve 23 and a hot water outlet 27 from the vessel 10. The tempering valve 26 also connects to a hot water outlet 28 to a hot water distribution line (not illustrated).

A temperature and relief pressure outlet 29 in the vessel 11 is connected to a temperature and temperature and pressure relief valve 30, which is in turn connected to a drain 31.

Positioning of the electric heating element mounting point 32 is also illustrated relative to the valves and associated pipework of the system 20.

FIG. 3 illustrates an exemplary method of securing the water heater system 20 to a wall 40. Brackets 41 are provided for securing to the wall 40, and subsequently fixing to sockets provided in corresponding locations on the water heater 20. Where the water heater 20 is to be secured to a single wall 40, the four positions shown on the back face of the heater 20 may be used. Where the water heater 20 is to be positioned in a corner, the four diagonally opposite positions may be used.

FIG. 4 illustrates a wall mounted water heater system 100. The system 100 includes a cuboid water vessel 101 manufactured in substantially the same manner as vessel 10, although it should be appreciated that the positioning of support plates may be changed to suit the connections to the remainder of the system 100 as herein described.

A pre-assembled valve assembly 102 is provided. The assembly 102 includes a pressure limiting stop valve 103, connected between a cold water inlet 104 configured to be connected to a cold water source (not illustrated), and a cold water expansion valve 105.

The assembly 102 also includes an isolation valve 106 is connected to the cold water expansion valve 105, and configured to be connected to a cold water inlet 107 of the vessel 10.

The assembly 102 also includes a tempering valve 108, connected to the cold water expansion valve 105. The tempering valve 108 is also configured to be connected to pipework 109 leading from a hot water outlet 110 of the vessel 101. The tempering valve 108 is also connected to a hot water outlet 1 11 configured to be connected to a hot water distribution line (not illustrated).

The assembly 102 also includes as part of a pipe manifold a hot and cold water expansion outlet 112, configured to be connected to a drain (not illustrated).

Expansion pipework 1 13 interconnects the assembly 102 and a temperature and pressure relief valve 1 14, which is in turn connected to a temperature and relief pressure outlet 115 in the top of the vessel 101.

Positioning of the electric heating element mounting point 116 in the base of the vessel 101 is also illustrated relative to the valves and associated pipework of the system 100.

The system 100 also includes a casing 1 17 around the valve assembly 102, having a watertight base acting as a drip tray. The casing 1 17 may be removable for installation, with an access panel (not illustrated) provided for maintenance.

The system 100 also includes a shell 118 surrounding the water vessel 101 , made of glass reinforced resin. The cavity between the vessel and 101 and shell 118 may be filled with insulation to assist in energy efficiency of the system 100.

Further, services such as pipework including hot water pipe109 and expansion pipework 1 13 may also pass through this cavity. In this embodiment, the only pipework exposed in the system 100 is a short section 1 19 interconnecting the expansion pipework 1 13 and temperature and pressure relief valve 114.

FIG. 5A illustrates an exemplary method of securing the water heater system 100 to a wall 200. Wall support brackets 201 are filament wound onto the water vessel 101 , having wings 202 extending to sit against the inner surface of the shell 118. Attachment points, such as threaded nuts 203 welded to the wings 203 provide means for mounting the system 100 to external brackets.

FIG. 5B illustrates an exemplary mounting system, in which a first Z bracket 204 is secured to the support bracket 201. A second Z bracket 205 is secured to the wall 200. The water heater system may thus be secured to the wall by lifting the first Z bracket 204 over, and into, the second Z bracket 205. FIG. 6A illustrates another exemplary water vessel 600 for a water heater. It should be appreciated that water vessel 600 may replace water vessel 1 1 in the water heater systems 20 and 100 substantially as described above.

The water vessel 600 includes a body having a continuous side wall 602, capped at either end by end caps 604 and 606 respectfully.

Referring to FIG. 6B, the side wall 602 has an exterior surface 610, and an interior surface 608. The shape of the cross-section of the vessel 600 through the side wall 602 is substantially that of a square with convex sides - i.e. a regular four sided shape made up of four outwardly curved arcs of even length and curvature. An alternate way of describing this shape is that of a superellipse defined in the Cartesian coordinate system as the set of all points (x, y) with

\ ^x \ ^r \y\ ^r where r, a and b are positive numbers; and 1 < r < 2.

Referring to FIG. 6C, the water vessel 600 is positioned within a shell 612 (equivalent to shell 1 18 described above with reference to water heater system 100), having a cuboid exterior. The gap 614 between the shell 612 and exterior 610 of the side wall 602 of the water vessel 600 is filled with an insulating material.

It may be seen that the cross-sectional area of the interior of the water vessel 600 (which defines volume for a given height) is significantly greater than that of a cylindrical vessel 616 having a diameter equivalent to the width of the water vessel 600. FIG. 7A shows a filament winding machine 700 for manufacture of the side wall 602 component of the water vessel 600. The winding machine 700 includes a mandrel 702 in the shape of the interior surface 608 of the side wall 602.

The mandrel 702 is mounted to a spindle 704 driven by an electric motor 708. A carriage 708 is provided, which can be driven along track 710 to guide the feeding of a filament (not illustrated) onto the mandrel 702.

Control of the machine 700 may be performed by controller 712. The controller 712 has a processor 714, memory 716, and other components typically present in such computing devices. In the exemplary embodiment illustrated the memory 716 stores information accessible by processor 714, the information including instructions 718 that may be executed by the processor 714 and data 720 that may be retrieved, manipulated or stored by the processor 714. The memory 716 may be of any suitable means known in the art, capable of storing information in a manner accessible by the processor 714, including a computer-readable medium, or other medium that stores data that may be read with the aid of an electronic device.

The processor 714 may be any suitable device known to a person skilled in the art. Although the processor 714 and memory 716 are illustrated as being within a single unit, it should be appreciated that this is not intended to be limiting, and that the functionality of each as herein described may be performed by multiple processors and memories, that may or may not be remote from each other.

The instructions 718 may include any set of instructions suitable for execution by the processor 714. For example, the instructions 718 may be stored as computer code on the computer- readable medium. The instructions may be stored in any suitable computer language or format.

Data 720 may be retrieved, stored or modified by processor 714 in accordance with the instructions 718. The data 720 may also be formatted in any suitable computer readable format. Again, while the data is illustrated as being contained at a single location, it should be appreciated that this is not intended to be limiting - the data may be stored in multiple memories or locations. The data 720 may include a record of control routines for the system machine, including control routines for individual components of the system such as the motor 708 and the carriage 710.

Referring to FIG. 7B, the motor 708 and carriage 708 may be controlled to produce a variety of winding patterns or weaves - for example a hoop pattern 722, a helical pattern 724, and a polar pattern 726 - each of which may be used in the production of the side wall 602. Referring to FIG. 8A, once the side wall 602 component of the vessel 600 is removed from the mandrel 702, end caps 604 and 606 are secured to the respective ends. In FIG. 8B, it may be seen that a lip 618 of the end cap 604 overlaps the side wall 602 by a distance 'd'. Resin is applied at the interface between the lip 618 and the side wall 602, and a layer of resin and fibre applied over the exterior of the join, to seal the interior of the water vessel 600 watertight. Returning to FIG. 8A, hoops 800 of rigid material such as may be fitted around the side wall 602 to assist in limiting bowing of the side wall 602 under pressure. It is envisaged that the hoops 800 may have a wall width greater that their thickness - i.e. being thicker in a direction perpendicular to the side wall 602 in order to better resist forces acting in that direction. The hoops 800 may be secured in place using a number of suitable means, for example by a spray lay-up layer overlapping the hoop 800 and side wall 602.

The entire disclosures of all applications, patents and publications cited above and below, if any, are herein incorporated by reference. Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the disclosure, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

Where in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth.

It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the present invention.

Aspects of the present disclosure have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.