Patent Application
20100147845
The present invention relates to fittings for a water storage tank for use, by way of example, for catchment and storage of water in domestic and rural settings.
The primary purpose of the fittings of the present invention is to transfer water into and out of the water storage tank.
The term “water” as used herein is understood in the broadest sense to include stormwater, rainwater, sewage, effluent and combinations thereof unless otherwise specified.
Tanks are commonly used for collecting rainwater runoff from roofs in domestic and rural settings via downpipes for storage of the water to supplement mains water supply and other freshwater sources. In many localities, it is a requirement for new dwellings under construction or extensions to existing dwellings to include a water storage tank.
Conventionally, such water storage tanks have a rounded profile and are bulky, the diameter of tanks being largely dependent on the water holding capacity. Such tanks are sealed to provide an interior volume for the reception and storage of water, and include steel tanks and tanks fabricated from plastics materials. The tanks have fittings in the form of: inlets for passage of water into the tanks; outlets for passage of water from the tanks; and overflow outlets.
International application PCT/AU2007/000479 entitled “Water Storage Tank” lodged on 27 Apr. 2007 in the name of the applicant and published as International publication WO 2007/124530 describes and claims an invention of another type of water storage tank that comprises an outer shell that defines an interior of the tank and at least one water catchment bag located in the tank interior. By using the bag or bags to collect and store water, the outer shell of the tank need not be sealed for retention of water. Moreover, the bag or bags may be arranged in a standing, self-supporting position within the outer shell of the tank to thereby provide their own structural support independently of the shell when the bag or bags are filled with water in use. This allows the outer shell of the tank to be relatively thin-walled with a concomitant saving in the cost of materials used for its fabrication. Such tanks also have fittings in the form of: inlets for passage of water into the tanks; outlets for passage of water from the tanks; and overflow outlets.
The disclosure in the above-mentioned International application is incorporated herein by cross-reference.
The fittings of the present invention are purpose designed for water storage tanks of the type described and claimed in the above-mentioned International application that have at least one internal water catchment bag, preferably a self-supporting bag, located in the interior of an outer shell.
The purpose-built structure of the fittings of the present invention distinguishes the fittings from fittings for conventional water tanks.
The fittings of the present invention comprise three separate sub-systems for the above type of water storage tank, namely:
(a) an inlet sub-system for allowing the passage of water into the tank;
(b) an outlet sub-system for allowing the passage of water from the tank; and
(c) an overflow outlet sub-system for allowing the passage of water from the tank.
The present invention relates to the above-mentioned fittings separately.
The present invention also relates to a water storage tank that comprises an outer shell that defines an interior of the tank, at least one water catchment bag located in the tank interior, and any one or more than one of the above-mentioned fittings connected as required to the outer shell and the bag or bags.
Preferably the bag is a self-supporting bag formed from a polymeric material.
Preferably the tank shell has side walls and end walls and the bag is fabricated from flexible sheet material that is impervious to passage of water or other liquid and the bag has a structure such that when the bag is installed within the tank shell and filled with liquid, the side walls of the tank shell will not be subject to substantial, if any, water or other liquid pressure tending to distort the side walls.
Preferably the tank shell is elongated with parallel side walls and curved end walls and a lid, and with the length of the side walls being greater than the spacing between the side walls.
Preferably the bag comprises a series of interconnected tubular cells extending from a base of the tank to the top of the side walls and end walls, the configuration of the bag in its uninstalled state being such that when the bag is installed within the tank shell and is filled with water or other liquid, the cells at the respective ends of the bag engage the adjacent end wall of the tank shell and are deformed into a non-cylindrical shape, and the or each cell intermediate the end cells is deformed into an elongate shape transversely of the side walls of the tank, the or each intermediate cell having part-cylindrical end walls which are positioned in relation to the side walls of the tank shell when in the installed state whereby the side walls of the tank shell are not subject to substantial, if any, water or other liquid pressure tending to distort the side walls.
Preferably the lid of the tank shell is a removable lid having an opening therein and the inlet sub-system is connected to the bag or to one of the bags and is coupled to the lid and arranged to extend through the opening in the lid.
Preferably the inlet sub-system has one of its components welded or otherwise connected to the bag
Preferably the overflow outlet sub-system has one of its components welded or otherwise connected to the bag.
Preferably the outer shell includes at least one opening in a lower section of the shell and the outlet sub-system is connected to the bag or to one of the bags and is coupled to the shell and arranged to extend through the opening in the shell.
Preferably the outlet sub-system has one of its components welded or otherwise connected to the bag.
Preferably the outer shell includes at least one opening in an upper section of the shell and the overflow sub-system is connected to the bag or to one of the bags and is coupled to the shell and arranged to extend through the opening in the shell.
Preferably the overflow sub-system has one of its components welded or otherwise connected to the bag.
The water storage tank fittings of the present invention are distinguished from conventional fittings by virtue of any one or more than one of the functions of:
(a) locating a water catchment bag or bags relative to an outer shell of a water storage tank;
(b) restraining the bag or bags from moving within the outer shell; and
(c) preventing leaks in the bag/shell interfaces; and
while ensuring the transfer of water into and out of the tank.
Furthermore, each of the fittings of the present invention has features over and above conventional fittings as will become more apparent from the following description.
The inlet sub-system is adapted to transfer water from outside a water storage tank into the tank. For example, the water may be rainwater harvested from roofs of houses or sheds via downpipes.
The inlet sub-system comprises a plurality of components.
Typically, the inlet sub-system comprises the following five individual components that fit together to form the assembled sub-system, as described below:
(a) A weld ring that can be positioned inside an outer shell of a water storage tank and affixed to a top of a water catchment bag located in the outer shell by fusing the weld ring, typically via a heat or an ultrasonic or another suitable fusion technique, to the bag. Typically, the weld ring is made from a polyethylene and is welded to the bag of the same or similar material specification. Typically the weld ring comprises an annular flange that has a flat surface for welding to the bag and a vertical shank with spaced-apart bayonet fixings that are adapted to connect the weld ring to a mating part of a retaining ring described hereinafter that is positioned outside the tank shell. Fusing the weld ring to the bag assists in the prevention of water leakage and positively assists in restraining the bag from collapsing when empty or partially full.
(b) A retaining ring that has complimentary bayonet fixings to those of the weld ring to allow the retaining ring and the weld ring to be quickly and efficiently coupled together. The retaining ring has an annular flange that contacts an outside surface of a top lid of the tank and a cylindrical sleeve that extends from the flange through an opening in the tank lid. The cylindrical sleeve terminates in an inwardly and upwardly extending lip that defines a channel for receiving a light guard of the inlet fitting, as described hereinafter. The bayonet fittings are provided in a transition between the flange and the sleeve. The arrangement is such that engagement of the bayonet fittings of the weld ring and the retaining ring clamps the tank lid between the weld ring and the retaining ring. The retaining ring also has holes that allow further fixings (screws or canoe clips or Christmas tree fixings or scrivets) to engage the tank lid to ensure a semi-permanent engagement of the weld ring, tank lid, and retaining ring. The retaining ring is typically made from an ultraviolet-stabilised polypropylene.
(c) An inlet/strainer that can be connected to the retaining ring via mating bayonet quick release fixings on the inlet/strainer and the retaining ring. The inlet/strainer has a suitable mesh, typically made from stainless steel wire, moulded into the component to comply with the current and intended regulations for the prevention of vermin and mosquitoes entering the tank and vector proofing as well as providing a filtration system for preventing leaves and other debris from entering the tank. When coupled to the retaining ring, the mesh extends across the opening in the tank lid. The inlet/strainer comprises a tamperproof/childproof function that is intended to prevent decoupling from the retaining ring by a child but does allow fast decoupling from the water storage tank by an adult for maintenance purposes, for example, to remove debris from the filter mesh. Typically, the body of the inlet/strainer is constructed from an ultraviolet-stabilised polypropylene.
(d) A generally circular light guard that is separate to the retaining ring but is formed to be housed within and mounted to the retaining ring and is retained in position by the inlet/strainer being positioned above the light guard. The light guard comprises an outer peripheral flange that can be positioned to extend into the above-described channel in the retaining ring. The light guard is formed to extend across the opening in the tank lid and to allow passage of water but restricts the passage of ultraviolet light into the tank (i.e. inside the bag or bags of the tank) This component is typically made from an ultraviolet-stabilised polypropylene.
(e) A compression gasket that prevents leakage of water from inside the bag or bags of the tank through the inlet system connections to the cavity between the outside of the bag and the inside of the outer shell under the conditions of backwash. This typically is constructed using moulded Seblex (Registered Trade Mark) polyolefin elastomer.
The entire inlet sub-system design facilitates the assembly of the bag or bags within the outer shell to the outer shell with innovative orientation of components, quick connect/locking features of mating components and multifunctional features such as allowing the passage of water but restricting the ingress of ultraviolet light and also providing for the optional fitment of a proprietary off the self filter bag.
Typically, there are two inlets per tank, preferably located at each end of the tank and preferably connected to the bags at the ends of the tank—in a tank comprising a plurality of bags—or to the end compartments in a single bag configuration in a tank.
Additionally, the inlet sub-system is so designed that, by the simple elimination of the above-described weld ring and the compression gasket, the remaining components can be utilised as an inlet sub-system on a conventional tank without modification to the remaining components or assembly process or procedure.
Additionally, the inlet sub-system is so designed that it can be used in combination with a submerged pump system.
The outlet sub-system typically transfers water from inside the tank to outside the tank for the purpose of using the stored water or other liquid contents in the tank.
The outlet sub-system comprises a plurality of components.
Typically, the outlet sub-system comprises five individual components that fit together to form the assembled sub-system, as described below:
(a) A main outlet body having a weld ring typically constructed from a polyethylene that is over-moulded to a spigot or shaft that is typically a cast and/or machined zinc alloy. The spigot/shaft can also be manufactured from other metallic materials or other fire resistant non-metallic materials. The spigot/shaft defines a support for the weld ring. The polyethylene weld ring is fusion-welded to the bag, typically of the same material specification as the weld ring. When positioned in relation to a tank, the metallic spigot protrudes through the tank shell and is threaded to allow the attachment of a plug or tap or other plumbing fittings that allows water flow from within the tank to outside the tank to be controlled or directed. The over-moulded zinc alloy spigot/shaft body also has, as part of its design, a mechanical key engagement to assist in the prevention of the relative rotational movement of weld ring (which has a mating mechanical key engagement with the shaft) to spigot/shaft whilst under a torsional load. The weld ring assists in the prevention of water leaks from the bag to the outer shell and in combination with other components in the outlet sub-system prevents the bag from twisting when the fittings are under torque by the actions of plumbers fitting external apparatus onto the outlet spigot/shaft. The weld ring has a “dog” clutch feature that comprises a plurality of dogs that can engage with a “dog” clutch feature of an internal adaptor plate described hereinafter to prevent rotation when either the fitting is tightened from the external protruding spigot/shaft or plumbing fittings are attached to the externally projecting spigot/shaft of the outlet.
(b) An internal adaptor plate that is adapted to orientate the outlet body within the tank shell and is formed to contact the inside of the tank shell. Specifically, in situations in which the tank shell is made from profiled (such as corrugated) panels, the internal adaptor plate has a mating wave-type profile that conforms to the internal corrugations of the tank shell. This feature makes it possible to self orientate the vertical location of the internal adaptor plate to the tank shell via the wave-type profile (corrugations) of the tank shell inner surface. The internal adapter plate also has a mating “dog” clutch feature, i.e. a series of openings to receive and engage the dogs of the mating weld ring. Typically, this component is manufactured from a polypropylene. The inner surface of the internal adaptor plate, i.e. the surface that faces inwardly when the internal adaptor plate is positioned in a tank shell, also transitions gently to the inner surface of the tank inner shell such that the bag flows over the face of the component not to induce stress into the bag under hydrostatic load conditions.
(c) An external adaptor plate is formed with a profile, such as a wave-type profile in the case of a corrugated tank shell, to mate to the outer profile of the tank shell and to provide a transition from the profile to a flat bearing surface that enables a lock nut described hereinafter to engage against and tighten the entire outlet assembly. In situations in which the tank shell is made from profiled (such as corrugated) panels, the external adaptor plate is formed so that the profile in plan view is such that it is a common component that suits all sweeps of the tank range. This is further facilitated by the next described component, i.e. a compressible gasket, which is formed to assist in compensating for differences in the fixed sweep of the external adaptor plate and the various sweeps of the water tank range. Typically, the external adaptor is manufactured from a zinc alloy for the purposes of fire resistance. It can also be manufactured from other metallic or non-metallic fire resistant materials.
(d) A lock nut, which is typically a left handed thread matching that of the shaft body, that is adapted to engage the spigot/shaft of the main outlet body. The engagement makes it possible to force the external and the internal adaptor plates against outer and inner surfaces respectively of the tank shell. For the same reasons as the spigot/shaft and the external adaptor, typically this component is manufactured from a zinc alloy but is not restricted to such a material choice where other metallic or non-metallic materials with fire resistance characteristics could also be suitable for this application.
(e) A compressible gasket is used in conjunction with the external adaptor plate to make a smooth transition from a common profile in plan view of the above-mentioned external adaptor plate and the outer surface of the tank shell. Typically, this component is constructed from moulded silicon.
Typically, there are two outlet sub-systems, one at each end of the tank down towards the bottom of the tank, preferably connected to each of the end bags in a plurality bag construction or at the end cells of the bag.
Additionally, the outlet sub-system is so designed that the components can be utilised as an outlet sub-system on a conventional tank with the simple addition of two compression gaskets, one between the weld ring and internal adaptor and the other between the internal adaptor and the tank shell and with little change to the assembly process or procedure.
The overflow sub-system transfers water (or other liquid as deemed suitable) from inside the water storage tank to the outside of the tank under a full tank capacity situation and is designed to prevent the water from backwashing out of the inlet sub-system. It can be allowed to vent to atmosphere. However, in an urban situation it is more typically plumbed into a storm water system to allow the excess water superfluous to the tank stored volume to escape to the storm water drainage system.
The overflow sub-system comprises a plurality of components.
Typically the overflow sub-system comprises five individual components that fit together to form the assembled sub-system, as described below:
(a) A weld ring that is fusion welded to the end bag or bags positioned in a tank shell. The material is typically a polyethylene. The weld ring comprises an oval flange that provides a flat weld surface and a sleeve that extends from an inner edge of the flange. The flange also provides a surface on which a compression gasket described hereinafter seals the weld ring to the body of the overflow sub-system described hereinafter. The sleeve is designed to be a female type engagement such that the overflow body male engagement fits inside the spout of the weld ring.
(b) An overflow body that has an oval sleeve with outwardly operable snap lock fittings is designed to engage with the sleeve of the weld ring. The dimensions, including the lengths of the sleeves are selected so that the sleeve of the weld ring can extend into the sleeve of the overflow body and the snap lock fittings of the overflow body can engage the flange of the weld ring and etain the two components together. The assembly of the two components together also relies on the compressive characteristics of the compression seal gasket described hereinafter to preload the snap lock fittings. The overflow body has a cross sectional transition from oval to round that provides for the same cross sectional area from inner to outer shape (oval to round) and provides for additional volume retention inside that tank by virtue of the bottom invert of the overflow body being substantially higher on the inside of the tank than the bottom invert of the overflow body on the outside of the tank. It is noted that alternative forms of the overflow body have transitions that mate with other shapes of pipes (stormwater), for example rectangular. When positioned in relation to a tank, the overflow body transitions from inside the tank shell to the outside of the outer shell by passing through the shell surface and has a number, typically four, screw bosses that engage on the inner surface of the outer shell regardless of the sweep of the tank. This is achieved by a combination of sweep detail in the plan view of the overflow body and the location and dimensional depth of the screw bosses that allow the positive location of the bosses on the inner surface of the tank shell at all times independent of the sweep of the tank. The overflow is typically constructed from an ultraviolet-stabilised poly vinyl chloride (PVC), which allows it to be connected to standard external plumbing accessories by solvent welding. The inner surface of the overflow body also transitions gently to the inner surface of the tank inner shell such that the bag flows over the face of the component not to induce stress into the bag under hydrostatic load conditions.
(c) An inner compression gasket that seals the weld ring flange to the back end (inner side) of the overflow body to prevent water ingress from the bag to the inner tank shell as well as providing preload for the snap lock fasteners on the overflow body to the weld ring sleeve. Typically, this component is constructed from a moulded compound but is not restricted to this material and as with all gaskets in this document can be constructed from any material whose mechanical and short and long-term durability performance characteristics meet the requirements of the application.
(d) An outer compression gasket is used in conjunction with the external retaining ring to make a smooth transition from a common profile in plan view of the following mentioned external retaining ring and the 4 different sweeps of the outer surface of the tank shell. Typically, this component is constructed from moulded Seblex but is not restricted to this material and as with all gaskets in this document can be constructed from any material whose mechanical and short and long-term durability performance characteristics meet the requirements of the application.
(e) An external retaining ring having an inner surface that has a wave-type profile that mates to the outer profile of the corrugated tank shell and provides a transition from the corrugation profile to flat outer or outboard surface. An important feature of the external retaining ring is that the profile in plan view is such that it is a common component that suits all 4 sweeps of the tank range. This is further facilitated by the above component, a compressible gasket, to assist in compensating for the difference in the fixed sweep of the external retaining ring inner surface and the various sweeps of the water tank range. Typically, the external retaining ring is manufactured from ultraviolet stabilised polypropylene. It can also be manufactured from other non-metallic or metallic materials suitable for this application. The external retaining ring is assembled to the overflow body by a number, typically four, of “high-low” screw fixings, typically stainless steel, extending into the corresponding four off-bosses of the overflow body. Other fixings options such as, for example, clips or self tapping screws can substitute for the “high-low” fixings described above. This attachment procedure then holds the overflow sub-assembly rigidly to the tank shell by compression, which in turn locates and restrains the bag at this specific location. Typically, there is one overflow sub-system but not necessarily restricted to one, at the end and the top of the tank preferably connected to the end bag in a tank construction having a plurality of bags or at the end cells of the bag in a multi-compartment single bag construction.
Additionally, the overflow sub-system is so designed that, by the simple elimination of the above-described weld ring and the internal compression gasket, the remaining components can be utilised as an overflow sub-system on a conventional tank without modification to the remaining components or assembly process or procedure. Furthermore, these sub-systems can also be utilised on other conventional corrugated tanks of round construction (as distinct from oval tanks of the “Slimline®” range) where the diameters of such tanks suit the sweep of the fittings components.
According to the present invention there is also provided each of the components of the above-described inlet sub-system, outlet sub-system, and overflow sub-system as separate components.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in this specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed in Australia or elsewhere before the priority date of this application.
Throughout this specification the word “comprise”, or variations thereof such as “comprises” or “comprising”, 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.
The features and advantages of the present invention will become further apparent from the following detailed description of preferred embodiments together with the accompanying drawings.
The present invention is described further by way of example with reference to the accompanying drawings, of which:
The fittings shown in the Figures are adapted to be used as part of a water storage tank of the type described and claimed in the above-mentioned International publication WO 2007/124530, incorporated herein by cross-reference.
Whilst not shown in the drawings (but as shown in the drawings of the International publication), the water storage tank comprises an outer shell (not shown) that defines an interior of the tank, a series of openings (not shown) in upper and lower sections of the shell to accommodate the fittings, a plurality of self-supporting water catchment bags (not shown) made from a polymeric material located in the tank interior, and a base (not shown) supporting the outer shell and the bags.
Typically, the tank shell is elongated with parallel side walls and curved end walls and a removable lid, and with the length of the side walls being greater than the spacing between the side walls.
Typically, the side walls and the end walls of the outer shell is made from panels that are fabricated from thin-walled (typically 0.6 mm and optionally 0.55 mm or thinner) corrugated steel. The end and side panels overlap and are respectively secured together by fasteners typically in the form of galvanised bolts or solid rivets received in aligned apertures defined in the panels, thereby forming joints. Generally, the outer shell of the tank has a width of from about 400 nun to about 1,500 mm but is not necessarily restricted to this range. The length of the outer shell typically is in a range of from about 1,400 mm to about 3,600 mm in length. The height of the outer shell typically is in a range of from about 1,300 mm to about 2,500 mm. Typically, the lid of the outer shell is fabricated from thin-walled steel.
The fittings shown in the Figures comprise an inlet sub-system 3 having the above-described components in the outer shell for passage of water into the bags, an outlet sub-system 47 having the above-described components in the outer shell for passage of water from the bags out of the tank, and an overflow sub-system 77 having the above-described components that is plumbed to a drainage system in an upper region of the tank.
Each of the embodiments of the fittings shown in the Figures is now described with reference to the Figures
The inlet sub-system 3 comprises the following five individual components that fit together to form the assembled sub-system shown in
(a) A weld ring 5 that can be positioned inside an outer shell of a water storage tank and fixed to a top of a water catchment bag located in the outer shell by fusing the weld ring, typically via a heat or an ultrasonic or another suitable fusion technique, to the bag. The weld ring is made from a polyethylene and is welded to the bag of the same or similar material specification. The weld ring comprises an annular flange 7 that has a flat surface for welding to the bag and a vertical shank 9 with spaced-apart upwardly and inwardly turned bayonet fixings 11 that are adapted to connect the weld ring to a mating part of a retaining ring described hereinafter that is positioned outside the tank shell.
(b) A retaining ring 13 that has complimentary bayonet fixings 15 to those of the weld ring 3 to allow the retaining ring 13 and the weld ring 3 to be quickly and efficiently coupled together. The retaining ring 13 has an annular flange 17 that contacts an outside surface of the lid of the tank and a cylindrical sleeve 19 that, when positioned in relation to the tank, extends from the flange 17 through an opening in the tank lid. The cylindrical sleeve 19 terminates in an inwardly and upwardly extending lip 21 that defines a channel 23 for receiving a light guard of the inlet fitting, as described hereinafter. The bayonet fittings 15 are provided in a transition 25 between the flange 17 and the sleeve 19. The arrangement is such that engagement of the bayonet fittings 11, 15 of the weld ring 3 and the retaining ring 13 clamps the tank lid between the weld ring and the retaining ring. The retaining ring 13 also has holes 27 that allow further fixings (screws or canoe clips or Christmas tree fixings or scrivets) to engage the tank lid to ensure a semi-permanent engagement of the weld ring, tank lid, and retaining ring. The retaining ring is typically made from an ultraviolet-stabilised polypropylene.
(c) An inlet/strainer 29 that can be connected to the retaining ring 13 via mating bayonet quick release fixings on the inlet/strainer and the retaining ring. The inlet/strainer has a suitable mesh 33, typically made from stainless steel wire, moulded into the component to comply with the current and intended regulations for the prevention of vermin and mosquitoes entering the tank as well as providing a filtration system for preventing leaves and other debris from entering the tank. When coupled to the retaining ring 13, the mesh 33 extends across the opening in the tank lid. Typically, the body of the inlet/strainer is constructed from an ultraviolet-stabilised polypropylene.
(d) A generally circular light guard 35 that is separate to the retaining ring 13 but is formed to be housed within and mounted to the retaining ring 13 and is retained in position by the inlet/strainer 29 being positioned above the light guard. The light guard 35 comprises an outer peripheral flange 37 that can be positioned to extend into the above-described channel 23 in the retaining ring 13. The light guard 35 is formed to extend across the opening in the tank lid and to allow passage of water but restricts the passage of ultraviolet light into the tank (i.e. inside the bag or bags of the tank) This component is typically made from an ultraviolet-stabilised polypropylene.
(e) A compression gasket 41 that prevents leakage of water from inside the bag or bags of the tank through the inlet system connections to the cavity between the outside of the bag and the inside of the outer shell under the conditions of backwash. This typically is constructed using moulded Seblex polyolefin elastomer.
The outlet sub-system 47 comprises five individual components that fit together to form the assembled sub-system shown in
(a) A main outlet body 49 having a weld ring 51 typically constructed from a polyethylene that is over-moulded to a spigot or shaft 53. The spigot/shaft 53 defines a support for the weld ring 51. The spigot/shaft 53 typically is a cast and/or machined zinc alloy. The spigot/shaft 53 can also be manufactured from other metallic materials or other fire resistant non-metallic materials. The polyethylene weld ring 51 is fusion-welded to the bag, typically of the same material specification as the weld ring. When positioned in relation to a tank, the metallic spigot 53 protrudes through an opening in the tank shell and is threaded (not shown) to allow the attachment of a plug or tap or other plumbing fittings (not shown) that allows water flow from within the tank to outside the tank to be controlled or directed. The over-moulded zinc alloy spigot/shaft 53 also has, as part of its design, a mechanical key engagement to assist in the prevention of relative rotational movement of the weld ring 51 (which has a mating mechanical key engagement with the shaft) and the spigot/shaft 53 whilst under a torsional load. Specifically, the weld ring 51 has a “dog” clutch feature 55 in the form of a plurality of spaced-apart dogs that can engage with a “dog” clutch feature of an internal adaptor plate 57 described hereinafter to prevent rotation when either the fitting is tightened from the external protruding spigot/shaft 53 or plumbing fittings are attached to the externally projecting spigot/shaft 53 of the outlet.
(b) An internal adaptor plate 57 that is mounted to the spigot/shaft 53 and orientates the outlet body 49 within the tank shell and is formed to contact the inside surface of the tank shell. Specifically, the internal adaptor plate 57 has a mating wave-type profile 59 to the internal corrugations of the tank shell. This feature self orientates the vertical location of the internal adaptor plate 57 to the tank shell via the wave-type profile (corrugations) of the tank shell inner surface. The internal adapter plate 57 also has a mating “dog” clutch feature, i.e. a series of openings 61 to receive and engage the dogs 55 of the mating weld ring 51 of the outlet body 49. Typically, this component is manufactured from a polypropylene. The inner surface of the adaptor plate 57, i.e. the surface 63 that faces inwardly when the internal adaptor plate 57 is positioned in a tank shell, transitions gently to the inner surface of the tank inner shell such that the bag flows over the face of the component so as not to induce stress into the bag under hydrostatic load conditions.
(c) An external adaptor plate 65 is formed with a wave-type profile 67 to mate to the outer profile of the corrugated tank shell and to provide a transition from the corrugation profile to a flat bearing surface that enables a lock nut 69 (
(d) A lock nut 69 (
(e) A compressible gasket 73 is used in conjunction with the external adaptor plate 65 to make a smooth transition from a common profile in plan view of the above-mentioned external adaptor plate and the different sweeps of the outer surface of the tank shell. Typically, this component is constructed from moulded Seblex polyolefin elastomer. This component could be made from any suitable material.
The overflow sub-system 77 comprises five individual components that fit together to form the assembled sub-system shown in
(a) A weld ring 79 that is fusion welded to the end bag or bags positioned in the tank shell. The weld ring 79 is typically made from a polyethylene. The weld ring 79 comprises an oval flange 81 that provides a flat weld surface and a sleeve 83 that extends from an inner edge of the flange 81. The flange 81 also provides a surface on which a compression gasket 95 described hereinafter seals the weld ring 79 to the body of the overflow sub-system described hereinafter. The sleeve 83 is designed to be a female type engagement such that the overflow body male engagement fits inside the spout of the weld ring 79.
(b) An overflow body 85 that has an oval sleeve 87 with outwardly operable snap lock fittings 89 is designed to engage with the sleeve 83 of the weld ring 79. The dimensions, including the lengths of the sleeves 87, 83 are selected so that the sleeve 83 of the weld ring 79 can extend into the sleeve 87 of the overflow body 85 and the snap lock fittings 89 of the overflow body 85 can engage the flange 81 of the weld ring 79 and retain the two components together. The assembly of the two components together also relies on the compressive characteristics of the compression seal gasket 95 described hereinafter to preload the snap lock fittings 89. The overflow body 85 has a cross sectional transition 93 from oval to round that provides for the same cross sectional area from inner to outer shape (oval to round) and provides for additional volume retention inside the tank by virtue of the bottom invert of the overflow body 85 being substantially higher on the inside of the tank than the bottom invert of the overflow body 85 on the outside of the tank. When positioned in relation to the tank, the overflow body 85 transitions from inside the tank shell to the outside of the outer shell by passing through the shell surface and has a number, typically four, screw bosses that engage on the inner surface of the outer shell regardless of the sweep of the tank. This is achieved by a combination of sweep detail in the plan view of the overflow body and the location and dimensional depth of the screw bosses that allow the positive location of the bosses on the inner surface of the tank shell at all times independent of the sweep of the tank. The overflow is typically constructed from an ultraviolet-stabilised poly vinyl chloride (PVC), which allows it to be connected to standard external plumbing accessories by solvent welding. The inner surface of the overflow body 85 also transitions gently to the inner surface of the tank inner shell such that the bag flows over the face of the component not to induce stress into the bag under hydrostatic load conditions.
(c) An inner compression gasket 95 that seals the weld ring flange 81 to the back end (inner side) of the overflow body 85 to prevent water ingress from the bag to the inner tank shell as well as providing preload for the snap lock fasteners on the overflow body to the weld ring sleeve 79. Typically, this component is constructed from a moulded Seblex polyolefin elastomer compound but is not restricted to this material and as with all gaskets described herein can be constructed from any material whose mechanical and short and long-term durability performance characteristics meet the requirements of the application.
(d) An outer compression gasket 97 is used in conjunction with the external locking ring described hereinafter to make a smooth transition from a common profile in plan view of the external locking ring and the four different sweeps of the outer surface of the tank shell. Typically, this component is constructed from moulded Seblex polyolefin elastomer but is not restricted to this material and as with all gaskets in this document can be constructed from any material whose mechanical and short and long-term durability performance characteristics meet the requirements of the application.
(e) An external retaining ring 99 having an inner surface 101 that has a wave-type profile that mates to the outer profile of the corrugated tank shell and provides a transition from the corrugation profile to flat outer or outboard surface. An important feature of the external retaining ring 99 is that the profile in plan view is such that it is a common component that suits all four sweeps of the tank range. This is further facilitated by the above component, a compressible gasket, to assist in compensating for the difference in the fixed sweep of the external locking ring inner surface and the various sweeps of the water tank range. Typically, the external retaining ring is manufactured from ultraviolet stabilised polypropylene. It can also be manufactured from other non-metallic or metallic materials suitable for this application. The external retaining ring 99 is assembled to the overflow body 85 by a number, typically four, of “high-low” screw fixings, typically stainless steel, extending into the corresponding four off-bosses of the overflow body. This attachment procedure then holds the overflow sub-assembly rigidly to the tank shell by compression, which in turn locates and restrains the bag at this specific location.
While a number of embodiments of the fittings in accordance with the present invention have been described, it will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention without departing from the spirit or scope of the invention as broadly described. The embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007902676 | May 2007 | AU | national |
| 2007906561 | Nov 2007 | AU | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/AU2008/000700 | 5/19/2008 | WO | 00 | 1/12/2010 |
