NZ333185A - Process for manufacturing metal bodies - Google Patents

Abstract

A process of manufacturing a body hemispherical in shape comprises the steps of: a) bonding a plate 1 to a cylindrical shaped body 3 to form a two piece body; b) bonding the open edge of the two piece body so formed to a support means 7 and c) introducing pressure into the space between support means 7 and the two piece body, to stretch the two piece body.

Description

PROCESS FOR MANUFACTURING METAL BODIES technical fp5ij> This invention relates to a process for manufacturing metal bodies In particular, it relates to processes for manufacturing substantially hemispherical and spherical metal bodies BAffTTOWOUNP ART Metal workers have long been experimenting with forming rental into different shapes Such shapes may have mdo&trial or decorative - 1 O applications Wrought mm is ofie example of metal working intended to have significant visual appeal. Architecture is also another field in which shaped metal forms are extensively employed.

Spherical shapes are considered particularly attractive However, manufacturing metal spheres, especially hollow spheres, has to date been problematic.

As yet, hollow spheres have not been able to be constructed in one piece The components are either moulded or otherwise shaped, and then components of the sphere are welded together to produce a sphere. > Known methods of manufacturing spheres are accordingly expensive, complex and time consuming- For these reasons, the commercial and decorative applications of metal spheres are underutilised.

One known process of manufacturing hollow metal hemispheres and spheres begins with fully welding down a sheet metal disc to a heavy plate The heavy plate is termed a hydroplate, and traditionally has a conduit in the middle to permit the passage of preoaunsed fluids. The Printed from Mimosa due and heavy hydropiate are usually supported in. a frame Pressurised fluid, usually water, is introduced between the hydropiate and the welded down disc Because the edges are welded down, under pressure the body of the disc expands, ie ia "blown", to a dome shape.

Using this method, the disc is generally blown to a tonspherical shape, wherein the radius of the dome is equal to that of the distance of the diameter. This process can only be used for forming shallow domes If it ib attempted to blow the dome deeper, the welding of the disc to the hydropiate fails, thus destroying the process and wasting valuable materials and tune Smaller domes, and those made out of lighter gauge metals, are blown singly, wherein only one disc at a time is welded to the hydropiate and blown in the manner described above However, larger diameter domes, and those made from heavier gauge metals, c<uat be blown in pairs To do this, sheet metal discs are welded on both sides of the hydropiate, and water pressure introduced into the space between the discs and plate in the manner described above, with the two diaes being blown into domes at the same tune In this way, domes of the same sue and depth are blown without distorting the hydropiate If heavier gauged or larger diameter domes are blown singly, the hydropiate will deform upon application of pressure into th# apace between the hydropiate and the disc.

Known methods of forming domes singly and in pairs have certain disadvantages.

Printed from Mimosa The main disadvantage ib that the domes bo formed are ntscaBsarily shallow Thia is because of the weak link comprising- the weld between the disc and the hydropiate Hie weld will not withstand the pressure required when trying' to blow doxneB deeper than torisphencaL To form a hemisphere or sphere, domes must be welded together. This farther welding is time consuming and increases the likelihood of malformation or failure of a hemisphere or sphere.

Again, the initial weld, called a fillet weld, of the disc to the hydropiate is vulnerable to failure. This represents another problem of this known process which ahcrald desirably be overcome to aid easa of mani^actura of motal hnnu spheres and spheres Another blowing process that enables blowing domes slightly deeper than tonsphencal has been developed and ua known in the art This pror comprises adding a skirt between the disc and the hydropiate. Ilia skirt comprises a flat bar rolled into a cone or cylinder, the lower edge of which 10 fillet welded to the hydropiate The upper edge of the skirt is then welded with a filll penetration butt weld to the disc. TT10 skirt strengthens the board between the hydropiate and disc, and reduces the chance of weld failure When blown in the usual manner, a dome approximately 50% deeper 1han tonsphencal can be obtained.

A single flat disc cannot be blown to a hemisphere, as the sheet metal will not stretch to this extant without ripping apart However, it could be made possible if annealing the material part way through the blowing process were done This is considered an unpractical option due to the expense, initial outlay of such a set-up, and the tune taken in removing the discolouration stains after the heating process Full hemispheres 3 Printed from Mimosa PCTNZ97/00057 comprising half a complete sphere cannot be obtained by this process, and a number of domes so produced muat still bB welded together to form a sphere It would be beneficial to provide workers in the field with simplified methods of forming full hemic ,-therea and spheres. This would have obvious benefits of reducing the number of welds required compared to those m known proieflpes, resulting in reduced manufacturing costs and reduced potential for failure of the production processes The quality of hemispheres and spheres produced by known methods is also somewhat Lacking, and it would be beneficial to provide a new method of producing hemispheres and spheres of increased quaKty Advantageous new methods of forming hemispheres and spheres would also lead to enhanced manufacture and applications of same It is an object of the present invention- to address the foregoing desiderata or at leaBt to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only xascLoacBB or invention According to one aspect of the present invention there is provided a process of manufacturing a body substantially hemispherical in shape, comprising the steps ofi a) bonding a plate portion to a substantially cylindrical shaped body portion to farm a two piece bocjy, 4 Printed from Mimosa b) bonding the open edge of the two piece body so formed to a support means, c) introducing pressure into the space between the support means and the two piece body, to stretch the two piece body Preferably the plate is a disc shaped body, and for simplicity the description will be reatneted to same It is, however, envisaged that other shaped plates fell within the ambit if the present invention, and may be applied in various embodiments Throughout this specification reference will be made to "metal" bodies. Usually, the bodies manufactured in accordance with the methods of the present invention will be made of stainless steel However, other materials, such as other metals, may also be used In one embodiment of the present invention the substantially disc shaped piece of metal is a knuckled disc. A knuckled disc is a flat disc having a curved hp or nm around its circumference The lip or run may he formed at nght angles the plane of the disc, or may alternatively form an obtuse angle m relation to the plane of the disc body.

The disc, hereinafter referred to as a knuckled dxoc, is bonded to a substantially cylindrical shaped metal body to form a two piece body Usually the edge of the knuckle disc will be bonded to the open edge of the cylindrical metal body with a butt weld However, other methods of welding may be used if desired.

The substantially cylindrical metal body portion to which the knuckled disc (plate portion) is bonded may be a hoop having vertical sides. In *hm embodiment, the lip or run of the knuckled disc can extend at nght Printed from Mimosa PCT/NZ97/OOOS7 angles from the plane of the knucklsd disc such that the edge of the disc and an edge of the metal body are of the seme circumference and are welded together to form essentially a two piece body having sides substantially at a right angle to the plane of the knuckled disc. While the cylindrical body portion may be fabricated from a plurality of components, for simplicity we Bhall refer to the cylindrical body portion as comprising a single body and the resulting combination with the plate portion, as being a two piece body Alternatively, the substantially cylindrical shaped metal body portion may have aides not oriented at a right angle with regards to the plane of the diameter, such that the substantially cylindrical shaped metal body portion comprises a segment of a cone. In this embodiment, the circumference of one edge of the metal body portion, hereinafter referred to as a cone, will differ from the circumference of the other open edge of i the cone ; In this embodiment, the hp or run of the knuckled disc may be at an obtuse angle with respect to the piano of the disc surface, such that the edge of the knuckled disc has a circumference equal to that of the open edge of the cone having a smaller circumference After bonding the disc and cone together, tha open edge of the two piece body so formed has a circumference larger than that of the knuckled disc.

The open edge of the above described two piece body is bonded onto a support means, which will usually be a heavy plate although other support means are envisaged.

The heavy plate will preferably be a metal hydropiate having a centre hole to allow passage of a preaaunng agent through the hydropiate However, Printed from Mimosa PCT/NZ97/000S7 any support means to which the two piece body can be affixed ia within the wops of the invention. The support means to which the two piece body is bonded will hereinafter be referred to as a hydropiate.

In a preferred embodiment, the two piece body will be directly bonded to the hydropiate through welding Fillet welding is the preferred mesas of welding However, other means of welding may be used if desired.

However, in another embodiment the two piece body may not be directly fillet welded to the hydropiate. A metal skirt, which can be a flat bar rolled into a cone, may comprise an additional junction between the two piece body and the hydropiate The flat bar rolled into a cone, hereinafter referred to as a skirt, can then be fillet welded to the hydropiate.

However, for ease of manufacture and to reduce coats, in a preferred embodiment a two piece body comprising a cone and a knuckled disc is directly fillet welded to tha hydropiate A skirt is accordingly not required for manufacture of a metal body according to this aspect of the present invention After the two piece body is bonded to the hyd/oplate, pressure is introduced into the space between the hydropiate and the two piece body, thereby expanding the two piece body The process of exposing sheet metal to pressure is known in the art and is called "blowing" The process will hereinafter be referred to as such The usual method of blowing uses pressurised water. However, any other fluid or fluidued substance may be used if considered suitable As ia known, the blotting process requires both a source of water pressured water, which is usually an inlet pipe, and a means for releasing pressure, which is usually an air vent When blowing, the air vent is in the off position.

Printed from Mimosa However, it in envisaged that eocplosive fanning, which is hIbo known in. the art, could be used to blow the two piece body Either the "standoff technique" or the contact method could be used Hie standoff technique eompnses placing a aheet matal workplace over a female die, with an explosive charge and detonator supported at a distance away from the workplace Upon detonation, the force forma the workpiece into the shape of the die Usually the force of the explosion in transmitted through a medium, such as water This requires the procedure to take place in a tank The contact method comprises laying the explosive directly on the workplace, or separating it from the workplace with a thin layer of buffer material, no transmitting medium being present The two piece body is blown until it forms a substantially hemiaphencal shape Ab discussed above, using conventional techniques only relatively shallow discs may be obtained before the disc either fractures or npplec, or the weld holding the two piece body to the hydropiate failB However, using the above described method of forming a two part body, perfect hemispheres may be obtained Of course, tho depth and diameter of tho hemisphere obtained may bo varied at will. If a shallow dome ia required, pressure will not be applied to tho extent it will be if a deep hemisphere io desired.

In all embodiments diacosaed herein, a 16% stretch is accounted for According to another aspect of the present invention thaxe is provided & process of manufacturing a body substantially sphencal in shape comprising the steps cf: a) bonding a plate portion to a substantially cylindrical shaped body portion, to form a two piece body, 8 Printed from Mimosa b) bonding the open edge of the two piece body so formed to a support means. c) introducing pressure into the shape between the support means and the two piece body, stretching the two pieca body, d) repeating the process and bonding the open edges of the hemisphere bo manufactured Preferably a 'plate1 is a substantially disc shaped body portion In a preferred embodiment, the open edges of two hemispheres are welded together to farm a sphere. The type of welding will usually be butt welding, but any other means of fusing tho hemisphere is within the scope of the invention.

In yet another embodiment of the present invention there is provided a process of manufacturing a body substantially sphencal in shape comprising the steps of a) bonding the wide diameter edge of a substantially cone shaped body portion to each open edge of a substantially cylindrical shaped metal body portion, b) bonding a plate to the narrow diameter edge of each of the two said substantially cose shaped bodies, c) introducing pressure into the inside of the body so formed, stretching a tune.

Preferably the plate is a substantially disc *liaped body Printed from Mimosa In. a preferred embodiment the wide diameter edges of the substantially cone shaped places of metal are knuckled, and are butt welded to »»rK edge of the substantially cylindrical shaped metal body Once welded together, the metal body assumes a substantially octagonal appearance The substantially cylindrical shaped metal body preferably has straight sides at a right angle to the plane of the diameter of the cylindrical metal bocfy The substantially disc shaped pieces of metal, hereinafter termed knuckle discs, are butt welded to the knuckled cohob The knuckling of the cones and discs aids formation of the sphencal shape blowing In one embodiment pressure may be introduced into the octagonal appearing metal body through an entry point in one of the knuckled discs However, pressure may be introduced into the body in any desired manner, such as using explosive forming Pressure is continued until the octagonal appearing metal body is blown into a sphere This embodiment of the present invention accordingly enables the manufacture of spherical bodies without the use of a hydropiate. Clearly, this process has the potential to revolutionise the field of metal sphere forming Tho metfor problem in. known methods is that the weld of the body to the hydropiate often fails whan blowing, and the skill and care required in achieving exactly the same circumferences on each hemisphere for a perfect fit of the two hemispheres to form a sphere is time consuming. Also, perfect alignment is very difficult, and weld shrinkage in this final Printed from Mimosa assembly butt weld causes a slight dip - not producing a perfect sphere This is visible in. spheres being highly polished fos architectural purposes. This situation is obviated using the above described new process In yet a further aspect of the present invention there is provided a process of manufacturing a body substantially sphencal in shape comprising the steps of: a) bonding a plate portion to both open edges of a substantially cylindrical shaped metal body portion, b) introducing pressure into the three piece body so formed, thereby stretching the three piece body.

Preferably the plate portion is a substantially disc shaped piece of metal In this embodiment, the discs are knuckled, and ore weldad to the edges of the body with butt welds Pressure is introduced into the three puce body through a hole in a knuckle disc Throughout this specification reference haa been made to introducing pressure into a metal body via one inlet However, it should be appreciated that introducing pressure from more than one source into the body is within the scope of the invention, as lone 143 the wallc of the metal bodies are subjected to sufficient pressure to bring about expasisian In addition, although prssfronsed fluid such as water will usually be used to blow the metal bodies, explosive forming is also another means of blowing capable of use in the present invention. 11 Printed from Mimosa PCT7NZ97/(W057 The method envisaged being usad for the purposes of the preBent invention would be the "stand off™ method of explosive forming, where an explosive is detonated above tha workpiece, forcing it into a female die (also known in the art as the open system) The confined system may be used instead, where a complete die is employed, thus forming a sphere with a centrally placed explosive The methods described above hold obvious advantages for those seeking to efficiently manufacture metal hemispheres and spheres. The cost savings using the methods of the present invention are significant Constructing a sphere from two foil hemispheres requires less materials and con*traction tune than the existing method of using, for example, five 2/3 depths domeB. Another way of manufacturing spheres is to press components of Bpheres mechanically, rather than using blowing techniques This process is very expensive to set up.

It has been found that the methods of the present invention produce perfect hemispheres when the angle of the cone Bides and the depth of the cone in the two part and five part bodies are correctly judged The methods of producing spheres in a one piece fabrication without a hydropiate from either five picces or three pieces obviate the common occurrences of fracture at tho anchor weld, or splitting through the sheet metal itself when using existing blowing techniques. Labour intensity and excessive welding casta associated with conventional methods of forming spheres are also obviated.

Blowing hemispheres from two piece bodies comprising a disc and a cylinder has been discussed herein However, the applicant has recognised that deep domes and hemispheres cannot successfully be 12 Printed from Mimosa PCIYNZ97/00057 blown by welding a disc alone to a hydropiate - the recognition that more than one piece should make up the body to be blown ib of primary importance. As already discussed, it is considered that one piece of metal could only be formed into a full hemisphere with conventional methods by annealing the material part way through the process, or by the "deep drawing* method This is a completely different process, where the material to be shaped is allowed to flow into a mould This is a different field to stretch forming' of metals Accordingly, it is envisaged that the metal bodies to be blown could comprise more than two pieces Similarly, the above described manufacture of spheres hemispheres, cylinders and bends as discussed herein without a blowing plate may use metal bodies made of greater than 3 or 5 pieces as in the embodiments discussed.

The novel manufacturing techniques described herein open up many possibilities for new applications of spheres and hemispheres For example, in another embodiment of the present invention there ia provided a receptacle comprising a) a hollow sphere, b) support means for said sphere, c) inlet and outlet means for said sphere The receptacle in the preferred embodiment is intended for bulk milk collection on dairy farms However, the receptacle may also be of a different character, including tanks, silos or vats intended for any application 13 Printed from Mimosa The sphere can be manufactured by above described methods of the present invention, including from two hemispheres, or in a one piece fabrication eg from five pieces or three pieces, without requiring a blowing hydropiate.

The receptacle will hareinaft&r be referred to aa a sulk tomV However, use of this term is not to be seen as limiting In a preferred embodiment, the milk tank is supported by a frame arrangement extending half way up its sides However, the nature of the support means is essentially immaterial and any effective means is within the scope of the invention For example the milk tank can be supported by metal framing, a concrete plinth or plastic start The milk tank will usually be aited in conjunction with the Tnillrmg Bhed and be sited outside, or wsida the milking shed A conduit supplying milk into the tank from the shed, and a conduit from which milk will be delivered into the milk tanker collecting the milk are supplied. These conduits may be of any form known m the art.

A sphencal milk tank offers many advantages over those currently used Reference will now be made to types of milk tanks used particularly in New Zealand and Australia.

Milk, being warm when obtained from the cowe, should ideally be cooled quickly for optimum storage Storage conditions should aba ideally leave milk's leptolitic and Immunolo gic *1 character substantially unchanged At the 1995 New Zealand Milk Quality Conference it was identified that one of the major failings of New Zealand's milk industry is the poor standard of on-fann cooling (Dairy Exporter, November 1995, p. 52 etaeq) 14 Printed from Mimosa W097M1979 PCT/NZ9 7/D0057 The current standard of cooling' milk to 7 degrees C within approximately 4 and a half hours is likely to be amended to 4 degrees C within approximately 3 hours of the start of milking The sphencal milk tank provided as a further aspect of the present invention will accordingly be of great benefit m achieving the above new standard due to its enhanced cooling efficiency Most Australian milk tanks are barrel shaped cylinders supported horizontal to the ground. These horizontal tanks have cooling pads extending up almost half the height of the horizontal barrel Typical barrels are 10,000 htre capacity A. typical horizontal barrel would have to measure 4 4 metres in length by 1 7 metres in diameter to expose the some surface area of milk to a cooling pad as in a spherical tank of 10,000 litre capacity manufactured according to the methods of the present invention hs wng a diameter of 2 7 metres and a cooling pad from the bottom to half way up its side Clearly, the aame'amount of cooling pad operate over a greater surface area of the sphere, than the horizontal barrel A sphencal milk tank demonstrably cools milk more effectively than a horizontal tank, enhancing storage of the milk awaiting collection In New Zealand, the barrel shaped milk tanks are supported vertical to the ground It is cheaper to do this than to support them horizontally In New Zealand, cooling the milk is not treated as high a priority as it is in Australia In a typical New Zealand tank, only 4J/2 m2 of cooling pad is used, compared with 11m2 in a typical horizontal Australian tank In New Zealand milk tanks, the cooling pad usually comprises a dimple pad on the bottom inner surface of the task. Sometimes, tanks may also have a pad on a side wall, but the combination of these two pads is not as efficient as having a cooling pad extending half way up the curved Printed from Mimosa surface of a tank. In addition, m New Zealand milk tanks Eire often pieced outside. This renders a more efficient means of cooling the milk tanks m summer more desirable. The provision of a spherical tnnlr would address that perceived need Another advantage of a sphencal milk tank is that it enhances efficiency of agitation of milk With a spherical tank, the agitator will start agitating the milk almost as soon as a minimal quantity of milk has entered the tank This is because it will concentrate in the bottom of the sphere, providing a critical quantity of milk. In contrast, conventional tanks can require a volume of up to 500 litres before activation of the agitator This can mean that the milk ices up before it gets agitated Icing up of milk may have serious implications, particularly if the milk 19 being for research purposes. This is bacauao the qualities of the milk composition will be altared by freezing and crystallisation, and unmunoprotein'denatur&tioii may result.

Construction of sphencal milk tacks will require less base material than required with conventional techniques This is because the initial components are first welded together, and then stretched into shape Because the extension and thinning of the metal is gradual, the tank walls retain their integrity. Usually, the sphere will end up being thinnest at the centre of the discs ie at the centre top and bottom of the sphere. This is desirable, as the thickest area is where the greatest strength is required, which is half way up the tank height at the full circumference of the sphere. This is where mounting means preferably meet the sphere 16 Printed from Mimosa PCT/NZ97/OOOS7 Because of the shape of the sphere and the relative thinness of its walls compared to a convention tank, the support structure can be relatively light weight la conventional vertical tanks the flat bottom must be strengthened to a significant thickness to stop it bending under a large load of milk In contrast, the sphencal tank requires no additional bottom strengthening as the bottom hangs below the support structure which is supporting the load further up the sphere Due to the large area of circumference available for support attachment, the supporting structure can be relatively simple and lightweight - thus having competitive advantages A factor enhancing the strength of the sphere is that the stretching of the metal and construction actually- increases the tensile strength of the stainless steel.

Because of these benefits - in cost, in ease of construction and in efficacy in storing and cooling sulk - it is apparent that using the methods of the present invention to produce sphencal receptacles, pnmanly but not solely directed towards storing milk on farms, is of significant value to the industry.

The methods of the present invention also lend themselves to still further applications of potential value to industry. For example, a sphere could be used in. a large ball valve Current large circular ducting systems used in the dsuzy industry employ scalable butterfly valves in the ducts At the end of the day's batch cycle, the butterfly valve can be turned into the off position, enabling sides of the duct to be cleaned in place without 17 Printed from Mimosa PCT/NZ97/0OO57 water running into the dry powder part of the plant Butterfly valves have certain associated disadvantages - namely cost and difficulties with maintaining hygiene Using a sphere manufactured according to the methods of the present invention, a large ball valve co-old be used. Using ball valves is an accepted method of sealing, but the size of balls required for large ducts has to date prevented their use in this regard Another application of hemispheres and spheres of the present invention is in creating stainless steel pressurised water supply tanks Current tanks are constructed from mild steel, which are prone to rusting out and/or the bladder (if present) perishing These accordingly must be regularly replaced In addition, in the current design of a cylindrical body with tonsphencal heads, the body needs to be at least 4mm thiflr, and the heads at least 6mm. The applicant has found that due to the high tensile strength integrity of a sphere that only 2mm wall thickness will suffice A cost competitive stainless steel tank that will never rust out can accordingly- be provided Other application such as stainless steel or copper hot w.ater calorifiars are also within the scope of the invention , and mil address the stress corrosion cracking problems faced with conventional designs.

In yet another aspect of the present invention there is provided a procesB of manufacturing a curved tube comprising the steps of (a) Forming a substantially doughnut shaped body, and (b) Introducing pressure into the substantially doughnut shaped body so formed, stretching the body and (c) Cutting the stretched body, obtaining curved tubes IS Printed from Mimosa PCT/N297/00057 According to another aspect of the present invention there 13 provided a process substantially as discussed above further comprising the steps of (a) forming two plates having a bole xn. substantially the centre (b) forming two substantially cylindrical shaped bodies of differing diameters; wherein the diameter of the hole at the centre of the plates equals the diameter of the smaller cylindrical body and wherein the diameter across the whole of the plates is at least equal to the diameter of the larger cylindrical body (c) bonding the plates to both open edges of the larger cylindrical body (d) braiding the edge bordering the hole at the centre of the plates to both open edges of the smaller cylindrical body, forming a substantially doughnut shaped body (a) introducing pressure into the substantially doughnut shaped body so formed, stretching the body and (0 cutting the stretched body, obtaining curved tubas Preferably the plates are substantially disc shaped bodies, such that their edges will be bonded to the open edges of the cylindrical bodies.

The smaller and larger cylindrical bodies may either be straight sided, or may be fenucfcled such that the disc shaped bodies and cylindrical bodies curve to their bonded edges It will also be appreciated that the substantially doughnut shaped body may be made not only in a 3 piece fabrication, but alternatively in a 6, 7, 9 or any other pieced fabrication that proves effective 19 Printed from Mimosa PCI7NZ97/00057 The stretched body may be cut into two, producing two 180 degree bends, or alternatively m four to produce four 90 degree bends Of course, any length of curved tube may be cut from the stretched body Prior to introducing pressure the height of the substantially doughnut shaped body may preferably be 50% of the width of the vertical areolar section taken at any point of the doughnut shaped body The above processes will produce long, sweeping bends at a lower cost than those currently used in industry, which are usually mechanically fabricated in two half shells, preformed and then welded together Furthermore, the radius and diameters of such bends are able to be selected accordingly to requirements, whereas with conventional methods the tooling set-up dictates the dimensions able to be manufactured Altering dimensions accordingly requires expensive tooling alteration 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: Figure 1 is a side plan view of a two piece body sad skirt welded to a hydropiate in accordance with one aspect of the present invention, and Flours 2 is a side plan view of 9 hemisphere blown from the two piece body shown in Figure 1, and Printed from Mimosa Figure 3 is a aide plan view of a cone shaped two piece body and skirt attached to a hydropiate in accordance with another aspect of the present invention, and Figure 4 is a Bide plan view of a hemisphere blown from a cone shaped two piece body wherein the bottom of the cone is welded directly to the hydropiate in accordance with nwntboir aspect of the present invention, and Figure 5 represents a five piece body for blowing without uae of a hydropiate in accordance with a further aspect of the present invention, and Figure 6 is a side plan view of a sphere blown from the five piece body shown in Figure 5, and Figure 7 is a side plan view of a three piece body for blowing into a sphere without use of a hydropiate in accordance with another aspect of the present invention, and Figure 8 represents a side plan view of a sphencal milk tank, being a representation of one application of the spheres of the present invention Figures 9(a). (b) and fc) are side views of a three piece body being blown inside a restraint BEST MOPES FOR CAKRVPJH OTTT THE II CM a or* OK Referring- to Figure 1, a substantially disc shaped body portion is represented by the knuckled disc 1 21 Printed from Mimosa The knuckled due 1 is bonded by the butt weld 5 to a substantially cylindrical shaped body portion represented by the cylinder 3 The two piece body formed by tbe knuckled disc 1 and the cylinder S ifi bonded by a fillet weld 6 to a support means generally represented by the hydropiate 7 In Figure 1, a flat bar rolled into a cone and forming a supportive junction between the two piece body comprising the knuckle disc 1 and the cylinder 3 and the hydropiate 7 is represented by the skirt 9. In embodiment, the cylindrical metal body 3 has vertical sides Figure 2 represents a result of stretching the embodiment shown in Figure 1, thereby producing a hemisphere 11 Referring to Figure 3, the disc shaped body is represented by the knuckled disc 1 The knuckled disc is bonded to the cylindncal shaped metal body 3 represented by the cone 13 with a butt weld 5 The two piece body comprising the cone 18 and knuckle disc 1 is bonded to a support means represented by the hydropiate 7 and skirt 9, with a fillet weld 6 In Figure 4, a two piece body comprising a knuckled disc 1 and cone IS is directly bonded to the support means represented by the hydropiate 7 with a fillet weld 6 Referring to Figure 5, a further embodiment of the present invention is shown where the wide diameter edge of substantially cone shaped bodies represented by the cones 13 are bonded to each open edge of a substantially cylindncal shaped body represented by the cylinder 3 with butt welds 5 Substantially disc shaped bodies represented by the knuckled discs 1 are then bonded to the narrow diameter edge of each cone IS with a butt weld 5 Pressure is introduced to the inside of the five 22 Printed from Mimosa piece body so formed via the introduction means represented by the water pressure inlet 17 Figure 6 shows the result of stretching the embodiment shown m Figure 5, thereby obtaining a sphere 19 A further embodiment of the present invention, is shown w Figure 7, wherein substantially disc shaped bodies are represented by knuckled discs 1 The knuckled discs 1 are bonded with butt welds 5 to a substantially cylindrical shaped body represented by the cylinder 3 Pressure is introduced into the three piece body by way of the water pressure mlet 17, but may alternatively be introduced into the cylindrical body Figure 8 shows a receptacle comprising a hollow sphere represented by the sphere 21, and support meant: for said sphere 21 represented by the frame work 23. Inlet and outlet means for said sphere 21 are represented by the milk conduit piping 25 Referring to Figure 9(a) there is illustrated a three piece body comprising a cylinder 3 having knuckled discs 1 welded by butt welds 5 at each open end thereof restrained inside a restraint 29, herein shown as a heavy wall mild steel pipe restraint. The restraint 2a may alternatively be made from stainless ste-sl, concrete or any oilier suitable material.

The three piece body is then hydro expanded within the restraint 29, as shown in Figure 9(b), forming a cylindrical body The restraint 29 is then removed and the cylindrical body further hydro expanded to provide the body with curving edges which increases the pressure rating of the cylindrical body If the cylindrical body is desired 23 Printed from Mimosa FCT/NZ97/00057 to be used for a pressurised water tank, then legs 31, inlet valve 33, outlet valve 35, and pressure gauge switch 35 may al6o be added after hydro forming.

It can be clearly Been that the methods of the present invention for forming hemispheres and spheres of the present invention, and proposed applications of same, represent significant improvements over known art Using the methods of the present invention, large quantities of efficiently manufactured hemispheres and spheres will bB available for industrial and architectural appbcations In use, following the above described methods will enable the metal worker to quickly manufacture in a cost effective manner full hemispheres and sphereB Aspects of the present invention 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 as defined in the appended claims 24 Printed from Mimosa

Claims (25)

1. 25

   WHAT I CLAIM IS:

   1 A process of manufacturing a body substantially hemispherical in shape, comprising the steps of

   (a) bonding a plate to a substantially cylindncal shaped body to form a two piece body,

   (b) bonding the open edge of the two piece body so formed to a support means, and

   (c) introducing pressure into the space between the support means and the two piece
2. 2 A process as claimed m claim 1 wherein the plate portion is a disc shaped body
3. 3 A process as claimed in claim 1 or 2, wherein the body portions are made of stainless steel
4. 4 A process as claimed in claims 1-3 wherein the substantially disc shaped body portion is a knuckled disc
5. 5 A process as claimed in claims 1-4 wherein the support means is a metal hydropiate
6. 6 A process as claimed in claims 1-5 wherein pressure introduced into the space between the support means and the two piece body is pressunsed water or by way of explosive forming as hereinbefore descnbed
7. 7 A process of manufacturing a body substantially sphencal in shape compnsing the steps of

   (a) bonding a plate portion to a substantially cylindncal shaped body portion to form a two piece body,

   (b) bonding the open edge of the two piece body so formed to a support means,

   body, to stretch the two piece body

   INTELLECTUAL PROPERTY OFRCLI OF M z ffc

   2 4 DEC 13S9

   <y ^ ,

   26 V; , '■ , S }

   (c) introducing pressure into the shape between the support means and the two piece body, stretching the two piece body, and

   (d) repeating the process and bonding the open edges of the hemispheres so manufactured
8. 8 A process as claimed in claim 7 wherein the open edges of two hemispheres so manufactured are bonded together to form a sphere
9. 9 A process of manufacturing a body substantially spherical in shape comprising the steps of

   (a) bonding the wide diameter edge of a substantially cone shaped body portion to each open edge of a substantially cylindncal shaped metal body portion,

   (b) bonding a plate portion to the narrow diameter edge of each of the two said substantially cone shaped body portions, and

   (c) introducing pressure into the inside of the body so formed, stretching same
10. 10 A process of manufacturing a body substantially sphencal in shape as claimed m any previous claim, including the steps of

    (a) bonding a plate portion to both open edges of a substantially cylindncal shaped metal body portion, and

    (b) introducing pressure into the three piece body so formed, and stretching the three piece body
11. 11 The process as claimed m claim 10 wherein between steps (a) and (b) the three piece body so formed is held in a restraint, such that when pressure is introduced into the restrained three piece body, it is stretched into a substantially elongate cylindncal body
12. 12 The process as claimed m claim 11 wherein the restraint is a cylindncal heavy walled

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    b mild steel pipe restraint
13. 13 A substantially cylindncal body when made from a restrained three or five part body as herein described, with reference to the accompanying drawings
14. 14 A receptacle formed in accordance with the method or process of any previous claim, the receptacle compnsing

    (a) a hollow sphere or cylindncal body,

    (b) support means for said sphere or cylindncal body- and

    (c) inlet and outlet means for said sphere or cylindncal body i
15. 15 A receptacle as claimed in claim 14 wherein it is be used for bulk milk collection on dairy farms, tanks, silos or vats for any domestic or commercial application
16. 16 A receptacle as claimed m any one of claims 14 or 15 in which said hollow sphere or cylindrical body is manufactured in accordance with the method of any one of claims 1 through 12
17. 17 A process of manufactunng a curved tube compnsing the steps of

    (a) Forming a substantial doughnut shaped body, and

    (b) Introducing pressure into the substantial doughnut shaped body so formed, and stretching the body and

    (c) Cutting the stretched body, obtaining curved tubes
18. 18 A process of manufactunng a curved tube compnsing the steps of

    (a) forming two plate portions having a hole in substantially the centre,

    (b) forming two substantially cylindncal shaped bodies of different diameters,

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    wherein the diameter of the hole at the centre of the plate portions substantially equals the diameter of the smaller cylindncal body and wherein the diameter across the whole of the plate portions is at least equal to the diameter of the larger cylindrical body,

    (c) bonding the plate portions to both open edges of the larger cylindncal body,

    (d) bonding the edge bordenng the hole at the centre of the plate portions to both open edges of the smaller cylindncal body, forming a substantially doughnut shaped body,

    (e) introducing pressure into the substantially doughnut shaped body so formed, and

    (f) cutting the stretched body obtaining curved tubes
19. 19 A process as claimed in claim 18 wherein the cylindncal bodies may be straight sided or knuckled
20. 20 A process as claimed m claim 17 or 18 wherein the stretched body may be cut in two, thereby producing two 180° bends
21. 21 A process as claimed m claim 17 or 18 wherein the stretched body may be cut in four producing four 90° bends.
22. 22 A process as claimed in anyone of claims 17-21 wherein the substantial doughnut shaped body may be made from greater than three portions as herein before disclosed
23. 23 A curved tube made from the process of any one of claims 17 through 22
24. 24 A process for manufacturing a curved tube, substantially as descnbed herein with reference to the accompanying drawings
25. 25 A receptacle, substantially as descnbed herein with reference to the accompanying drawings

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