FIELD

[01] The present invention relates to a refractory nozzle and/or refractory nozzle component. More specifically, the present invention relates to a refractory nozzle for use in casting molten metal.

BACKGROUND

[02] In foundries, for example automotive foundries, devices such as bottom pour ladles, casting boxes, tundishes and the like are used extensively to pour molten metal into moulds. Such devices are provided with a refractory nozzle in their bottom through which the molten metal flows into the mould.

[03] It is important to achieve control over the flow of the molten metal through the nozzle. Known control methods include a refractory stopper in the interior of the casting box, the stopper being moveable with respect to the nozzle, thereby controlling the flow of metal. However, such a system has the problem that flow around the stopper can become turbulent, giving uneven flow and causing impurities to be pulled down into the mould from the casting box.

[04] Thus a need exists in the art to provide a means of providing improved control over the flow of molten metal through refractory nozzles. It is therefore an object of aspects of the present invention to address one or more of the abovementioned or other problems..

SUMMARY

[05] According to a first aspect of the present invention there is provided a nozzle component for a nozzle for molten metal casting, the nozzle component comprising a vortex restriction member operable to restrict the formation of a vortex in the flow of the molten metal through the nozzle.

[06] According to a second aspect of the present invention there is provided a nozzle for molten metal casting comprising a vortex restriction member operable to restrict the formation of a vortex in the flow of the molten metal through the nozzle.

[07] Suitably, the nozzle and/or nozzle component of the present invention comprises a bore having a channel for the molten metal to flow through, and the vortex reduction member comprises at least one projection extending into the flow channel. Preferably the projection extends from a side face of the bore. Preferably, the side faces of the projections are flat. Optionally, the end, top and/or bottom faces of the projections are flat.

[08] Suitably, the projections of the vortex restriction members are shaped such as to be operable to restrict radial motion of the molten metal whilst not substantially reducing the axial flow of the molten metal compared to a nozzle not having the vortex restriction member. [09] The vortex reduction member may comprise at least two spaced projections, preferably at least three spaced projections or at least four spaced projections. Preferably, the projections of the vortex reduction member are substantially equally spaced around the bore of the nozzle. More preferably, the projections of the vortex reduction member are arranged on the same lateral plane of the bore.

[10] Preferably, the bore of the nozzle or nozzle component is tapered, suitably tapered at the portion of the bore comprising the vortex reduction member, more preferably the gradient of the taper is greater at the portion of the bore comprising a vortex restriction member than at the longitudinally adjacent portions of the bore not comprising a vortex restriction member. Suitably, the bore is tapered substantially throughout its length.

[1 1 ] The nozzle may be a multi-component nozzle comprising at least an outer nozzle and an inner nozzle, wherein the vortex restriction member be arranged on the outer and/or the inner nozzle. Optionally, the nozzle may be a one component nozzle. The nozzle may comprise at least three nozzle components, preferably of three components such as an outer nozzle, an intermediate nozzle, for example a spigot flute, and an inner nozzle. The intermediate nozzle component may be operable to be arranged between the inner and outer nozzle. The outer nozzle may comprise a recess operable to receive the intermediate and/or inner nozzle component, preferably the recess is operable to receive the intermediate nozzle component and the inner nozzle component.

[12] Suitably the intermediate nozzle component comprises a vortex restriction member, preferably the inner and outer nozzles do not comprise vortex restriction members. Preferably, the length of the projections of the vortex restriction members are between 1 and 30% of the length of the bore, such as between 5 and 20%, or between 5 and 10%. Preferably, the length of the bore of the intermediate nozzle is between 1 and 30% of the length of the bore, such as between 5 and 20%, or between 5 and 10%.

[13] The vortex restriction member may be formed of a harder material than the bore-defining material of the nozzle. Preferably, the intermediate nozzle component comprising the vortex restriction member is formed, more preferably integrally formed, of a harder material than the other components in a multi-component nozzle, such as the inner and/or outer nozzle component. The vortex restriction member and/or the intermediate nozzle comprising the vortex restriction member may be formed of a material having a Mohs hardness of at least 7, such as at least 8. The bore defining material of the nozzle and/or the inner and/or outer nozzle may be formed of a material having a Mohs hardness of up to 7, such as up to 6.5. The vortex restriction member and/or the intermediate nozzle comprising the vortex restriction member may be formed of zirconia or tabula aluminium . The bore-defining material of the nozzle and/or the inner and/or outer nozzle may be formed of lower density material than the material of the vortex restriction member and/or the intermediate nozzle comprising the vortex restriction member material, such as an alloy comprising between 60-85wt% of aluminium .

[14] The components of the multi-component nozzle may be cemented or clamped together.

[15] Advantageously, the present invention reduces swirl of the molten metal that can form as it passes a control stopper. The present invention provides an improved casting stream, overcoming major problems with the manufacture of castings. In particular, the combination of a tapered bore with a vortex restriction member reduces the effects of ferrostatic problems associated with static casting moulds whilst also reducing turbulence when filling a casting. Furthermore, the present invention can allow for different bore diameters to be used depending on the application. An intermediate nozzle comprising the vortex restriction member can also be manufactured from different materials than the other nozzle components, such as an outer nozzle and/or an inner nozzle, to combat the wear abrasiveness of certain grade steels. The other nozzle components may also be formed of a lower density material reducing the risk of freezing of the molten alloy in the nozzle.

[16] According to a third aspect of the present invention there is provided a multi-pouring nozzle block comprising at least one nozzle component or nozzle according to the first or second aspect of the present invention.

[17] The multi-pouring nozzle block may comprise at least two nozzles wherein at least one nozzle is according to the first or second aspect of the present invention.

[18] According to a fourth aspect of the present invention, there is provided an apparatus comprising a multi-pouring nozzle block according to the third aspect of the present invention and a refractory plug manufactured to match the profile of at least one of the nozzles, preferably a nozzle according to the second aspect of the present invention, wherein the plug is operable to be seated in the nozzle. Preferably, the refractory plug is profiled such as to seat in the nozzle without any leaks in use. The nozzle may comprise a contact area curve and the refractory plug may be profiled to seat in the contact area curve of the nozzle, preferably without any leaks in use.

[19] The refractory plug may comprise a bar operable to extend downwardly through a nozzle and be secured at the outlet of the nozzle, preferably by a nut, wedge or gas spring.

[20] According to a fifth aspect of the present invention, there is provided casting apparatus for casting molten metal, comprising a nozzle component, nozzle, nozzle block or apparatus according to any aspect of the present invention and a vessel operable to contain a molten metal and compromising at least one outlet operable to receive a nozzle block, preferably the vessel is a metallurgical vessel, such as a ladle or casting box, for example a casting box. [21 ] The apparatus and/or block may comprise a refractory blank nozzle, suitably operable to be fitted to nozzle(s) that are not being used. Preferably, the blank is a blank inner nozzle operable to be fitted to the outer nozzle to restrict the flow of molten metal through the nozzle.

[22] The casting apparatus may further comprise a stopper control. Preferably, the casting apparatus comprises a single stopper control. Suitably, the casting apparatus is for automotive casting.

[23] The automotive foundry is different to standard foundries. It is predominately used in the manufacture of automotive ancillaries such as pumps brakes. Such casting machines cast up to 40,000 pieces per week and predominately it is cast iron not steel, but some do cast steel. To meet the high output demand from these casting lines, and to help reduce cost, manufactures are trying to improve output without adding more casting machines.

[24] A simple way is to have a mould with more than one pouring cup, having different centre points, this could be up to three different centre points. It is very difficult to locate the pouring nozzle over each cup by moving the casting machine to each centre. The present invention allows each pouring nozzle to have a different bore size to allow the correct mould filling time. This elevates the stopper throttling with an oversize nozzle diameter. Thus increases cast yield. This invention which allows the operator to use different nozzles with the same stopper control.

[25] According to a sixth aspect of the present invention there is provided a method of casting molten metal, preferably in casting apparatus according to the fifth aspect of the present invention, comprising the steps of:

a. arranging in a multi-component nozzle of a multi-pouring nozzle casting block, a refractory plug manufactured to match the profile of the nozzle, preferably the nozzle is according to the second aspect of the present invention; b. draining down the vessel operable to contain a molten metal and compromising at least one outlet operable to receive a nozzle block, preferably the vessel is a casting box;

c. removing the refractory plug; and

d. fitting a blank inner nozzle into the outer nozzle of the nozzle that has just been used.

[26] The method may further comprise fitting a refractory gasket over the nozzle before casting commences. Preferably, the plug is fitted before a casting operation proceeds.

[27] Advantageously, when an operator requires a different centre point, for example due to a mould size change the operator can accomplish this by simply draining down the casting box whilst still over the casting line, remove the refractory plug, thus allowing a clean nozzle aperture for the existing stopper to be orientated over the top of the aperture then a gasket can be fitted and locked down. This allows the operator to commence casting quickly with little casting delays. The introduction of the refractory blank inner nozzle and plug makes this safe and possible.

[28] According to another aspect of the present invention there is provided a refractory nozzle 9 that has a radical taper 9a throughout the nozzle body. A refractory spigot 4 that fits into recess 6 on the outer nozzle 9. A refractory inner nozzle 5 that also fits into recess 6 with a radical taper bore 5a. A refractory nozzle once complete comprising of 3 sections that has a rapid taper that matches from 9a down to 5a the exit point to allow different bore diameters to be used: This aspect of the invention relates to the control of molten metal. That is traditionally used in bottom pour ladles and tundishes. This is a very simple invention that will eliminate the turbulence whilst filling a casting. The inventor has at present 3 patents relating to this type of field (control of molten metal). On a previous patent refractory nozzle that is currently enforce, we have proven that a rapid taper throughout the internal bore, reduces the effects of ferrostatic problems associated with static casting moulds etc. I have now developed a spigot flute that is fitted inside of the bore. The nozzle comprises of 3 pieces, an outer nozzle and a spigot flute and an inner nozzle. The purpose of the spigot is to break up the natural swirl of the molten metal after it is passing the control stopper, i.e. reducing turbulence then having a rapid taper throughout the internal bore ensures a perfect casting stream , overcoming major problems with the manufacture of sound castings. Figure 2 shows an outer nozzle 9 with a rapid tapered bore 9a that has a recess 6 to accommodate the spigot flute. 4. Figure 2 shows an outer nozzle 9 with a rapid taper 9a and a recess 6 that 4 the spigot flute fits into and then is cemented together then 5 is fitted into 6 the recess and cemented together, the 9a 4a and 5a are tapered bores that match together resulting in the smallest bore at the exit point of 5a. Figure 3 shows the spigot flute 4 and the tapered bore 4a which can be manufactured in different materials than 9 the outer nozzle and 5 the inner nozzle to combat the wear abrasiveness of certain grade steels. Figure 1 shows the nozzle complete once assembled. .

[29] All of the features contained herein may be combined with any of the above aspects in any combination.

BRIEF DESCRIPTION OF DRAWINGS

[30] For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the following figures:

[31 ] Figure 1 shows a side sectional view of a first embodiment of the nozzle according to the second aspect of the present invention.

[32] Figure 2 shows a side exploded sectional view of the nozzle of Figure 1 .

[33] Figure 3 shows a top view of the intermediate nozzle of the nozzle of Figure 1 . [34] Figure 4 shows a schematic view of a first embodiment of a multi-pouring nozzle block according to the third aspect of the present invention.

[35] Figure 5 shows a schematic view of a second embodiment of a multi-pouring block according to the third aspect of the present invention.

[36] Figure 6 shows a side sectional view of the refractory plug of the block of Figure 5.

[37] Figure 7 shows a side sectional view of a casting apparatus according to the fifth aspect of the present invention containing the block of Figure 5 and with a stopper in a raised position.

[38] Figure 8 shows a side sectional view of the casting apparatus of Figure 7 with the stopper in a lowered position.

DESCRIPTION OF EMBODIMENTS

[39] Figures 1 and 2 show a nozzle 2 according to the present invention. Nozzle 2 is formed of outer nozzle 9, intermediate nozzle 4 and inner nozzle 5. Outer nozzle 9 has a rapidly tapered central bore 9a that has a recess 6 to accommodate the intermediate nozzle 4 and hold inner nozzle 5. The top half of bore 9A has a steeper taper than the lower half of bore 9A. The top half of bore 9A is formed of a curved bore face and the bottom half of bore 9A is formed of a straight bore face. Intermediate nozzle 4 and inner nozzle 5 also have central tapered bores 4A and 5A, respectively. Bore 4A is steeply tapered in a similar manner to the top half of bore 9A, but bore 4A has a straight bore face. The bore face of tapered bore 5A is also straight.

[40] As shown in Figures 3 and 3, intermediate nozzle 4 is further formed of vortex restriction projections 10a-d. Projections 10a-d are evenly spaced around bore 4A and are arranged on the same lateral plane of bore 4A. Each of projection 10a-d extends from the side face of bore 4A into the flow channel. Projections 10a-d have a triangular vertical cross-section and the outer upper and side faces of the projections 10a-d extend horizontally and vertically, respectively.

[41 ] In use, intermediate nozzle 4 is placed into the top of recess 6 and cemented into position. The top face of inner nozzle 5 is then abutted with the bottom face of intermediate nozzle 4 in recess 6. The components of nozzle 2 are then cemented together. When together, bores 9A, 4A and 5A are coaxial to form a radical tapered bore without steps that would influence the pouring stream and define flow channel A-B extending from opening A to exit B. The combined bore has a broadest point at A and a narrowest point at B. In use, molten metal enters the bore of nozzle 2 at A and exits at B. The formation of a vortex in the flow of the molten metal as it moves down the bore is restricted by projections 1 0a-d.

[42] Figure 4 shows nozzle block cast 1 containing two nozzles 20a and 20b according to the second aspect of the present invention. Intermediate nozzles 20a and 20b are as described for Figures 1 to 3. Accordingly, block 1 provides more than one nozzle aperture for different centre points. [43] Figure 5 shows nozzle block cast 30 which contains two nozzles 30a and 30b according to the nozzle of Figures 1 to 3. Nozzles 30a and 30b have curved contact areas 10 for contacting stopper 18. Figure 5 also shows a refractory plug 14 that has a metal bar cast into the centre 15 that passes through nozzles 9, 34b and 5 and protrudes through exit 6, where it can be secured at 16 by either nut/wedge or gas spring (as shown in Figure 6).

[44] Figures 7 and 8 shows casting apparatus 40. Apparatus 40 contains casting box 42 which has arranged in the lower wall the nozzle block cast of Figure 5. A stopper 18 is shown in the raised position above upper nozzle aperture 20a, where a gasket 17 is positioned over the aperture. In Figure 8 stopper 19 is lowered onto outer nozzle 10 and locked down to form a metal tight seal. Gasket 17 is flexible and is manufactured from a material that can withstand high temperatures of over 1000 ^s c so it does not contaminate the castings when the stopper is raised, it also ensures that stopper 1 8 does not stick to contact area 10.

[45] Apparatus 40 further includes refractory plug 14 which is profiled to contact area 10 so that it forms a seal without any leaks. Plug 14 is secured to contact area 10 by a metal rod 15 that is cast into 14 that passes through the bore of the nozzle.

[46] Figure 8 also shows an outer nozzle 9 with an inner blank nozzle 7 that is solid and which is fitted after the casting process has finished with that centre point and another centre point is to be used. This fitting of blank nozzle 7 ensures that there are no leaks whilst the other nozzle is being used. Figures 7 and 8 also show a metal base plate 8 that secures these pieces in position.

[47] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[48] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[49] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[50] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.