CA2008742A1 - Rotor - Google Patents
RotorInfo
- Publication number
- CA2008742A1 CA2008742A1 CA002008742A CA2008742A CA2008742A1 CA 2008742 A1 CA2008742 A1 CA 2008742A1 CA 002008742 A CA002008742 A CA 002008742A CA 2008742 A CA2008742 A CA 2008742A CA 2008742 A1 CA2008742 A1 CA 2008742A1
- Authority
- CA
- Canada
- Prior art keywords
- rotor
- coupler
- rotor stem
- stem
- pressed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/14—Closures
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/14—Closures
- B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening
- B22D41/18—Stopper-rods therefor
- B22D41/186—Stopper-rods therefor with means for injecting a fluid into the melt
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Ceramic Products (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Abstract
Abstract Rotor A rotor stem forming part of a rotary valve assembly for use with apparatus for handling of molten material, especially metal comprises a longitudinal body 21, formed from refractory materials by an isostatic pressing method, having one end 30;
40 adapted to receive a driving component, wherein said end contains, for attachment of an inert gas gas feed pipe 31; 41, a coupler 32; 42 which is co-pressed into the body during forming thereof by isostatic pressing and is formed of thin metal or from high strength ceramic material to allow direct fastening of the feed pipe by threaded connection or compression joint to a substantially solid rotor head.
(Fig. 2)
40 adapted to receive a driving component, wherein said end contains, for attachment of an inert gas gas feed pipe 31; 41, a coupler 32; 42 which is co-pressed into the body during forming thereof by isostatic pressing and is formed of thin metal or from high strength ceramic material to allow direct fastening of the feed pipe by threaded connection or compression joint to a substantially solid rotor head.
(Fig. 2)
Description
o~ ~
Z008~
oto~
This invention relates to a rotor stem forming ~art of a rotary valve assembly for use with apparatus for handling of molten material, especially metal. The invention is particularly useful in apparatus for controlling the pouring of melt from a tundish into a mould such as in the production of ingots or in the continuous casting of steel for example.
lo ~otary valve assemblies of a known type comprise a replaceable outlet component locatable in the base of a vessel such as a tundish and having a throughbore to act as an outlet passage from the interior of the vessel to the e~terior, with a cooperating rotatable closure component of generally columnar lS shape having an end surface adapted to bear upon a surface of the outlet component and having in that end surface an orifice registrable with the passage, and in its sidewall, an opening communicating with said orifice whereby a melt flow pathway out o~ the vessel may be formed by appropriate rotational control of the closure component. These components may be conveniently referred to as "nozzle" and "rotor stem"
components respectively. The cooperating surfaces of these components are usuaily complementary convex/concave surfaces to facilitate location o} one surface with respect to the 2S other.
Typically the rotor stem will be formed from particulate or granular refractory materials by an isostatic pressing method using arbors and void forming materials with appropriate curing and extensive machine finishing steps to provide a substantially cylindrical body having an axial throughbore and usually non-uniform exterior contour arising from the need to provide generallY thicker material at the nozzle contacting end Tor strength and surfaces for receiving a driving assembly 3s at the opposite end. In use the rotor stem is installed in a substantially vertical position an~ a large proportion thereof immersed in molten material at very much higher temperatures than the upper end which is located in a drive assembly. The d~ive assembly includes components which transmit pressure ~, - ., ;, .
,~, . . . .
",~
,:; . . .
~ ;, ~. .
.. . .
.. . . . .
" ,, ,;. : .
., ~ , , .
,..... .. .
Z008~
oto~
This invention relates to a rotor stem forming ~art of a rotary valve assembly for use with apparatus for handling of molten material, especially metal. The invention is particularly useful in apparatus for controlling the pouring of melt from a tundish into a mould such as in the production of ingots or in the continuous casting of steel for example.
lo ~otary valve assemblies of a known type comprise a replaceable outlet component locatable in the base of a vessel such as a tundish and having a throughbore to act as an outlet passage from the interior of the vessel to the e~terior, with a cooperating rotatable closure component of generally columnar lS shape having an end surface adapted to bear upon a surface of the outlet component and having in that end surface an orifice registrable with the passage, and in its sidewall, an opening communicating with said orifice whereby a melt flow pathway out o~ the vessel may be formed by appropriate rotational control of the closure component. These components may be conveniently referred to as "nozzle" and "rotor stem"
components respectively. The cooperating surfaces of these components are usuaily complementary convex/concave surfaces to facilitate location o} one surface with respect to the 2S other.
Typically the rotor stem will be formed from particulate or granular refractory materials by an isostatic pressing method using arbors and void forming materials with appropriate curing and extensive machine finishing steps to provide a substantially cylindrical body having an axial throughbore and usually non-uniform exterior contour arising from the need to provide generallY thicker material at the nozzle contacting end Tor strength and surfaces for receiving a driving assembly 3s at the opposite end. In use the rotor stem is installed in a substantially vertical position an~ a large proportion thereof immersed in molten material at very much higher temperatures than the upper end which is located in a drive assembly. The d~ive assembly includes components which transmit pressure ~, - ., ;, .
,~, . . . .
",~
,:; . . .
~ ;, ~. .
.. . .
.. . . . .
" ,, ,;. : .
., ~ , , .
,..... .. .
- 2 ~0087~
from an actuator mechanism to the rotor to maintain close mating surface contact with the nozzle component.
It is conventional to provide such systems with ~eans for delivering an inert gas, e.g. argon, for reasons well known in the art such as purging o air to avoid melt oxldation pro~lems. ~ncorporation ef such gas supply means is an added difficulty. ~he way that this has been done in the past is to fit in the throughbore at the driven end o~ the rotor stem a lo vented plug into which is fitted a metal pipe by a separate forming operation. The pipe and plug are cemented into position and this does not always provide a satisfactory gas-tight joint. A typical multicomponent system currently in use is shown in Fig. 1. Problems which manifest themsel~es with such an assembly include the need to provide high mechanical strength at both hot and cold temperatures, close dimensional accuracy, especially at the driven end where mating with the driving assembly is required, and the need to provide gas-tight joints to avoid undesirable losses of the expensive ~0 inert gas.
Thus such a component is not easy to manufacture and an object -of the present invention is provide improvements therein whereby such problems are obviated or mitigated.
2s Accordingly th1s invention provides a rotor stem comprising a longitudinal body, formed from refractory materials by an isostatic pressing method, having one end adapted to receive a -driving component, wherein said end contains a coupler for ~-attachment of a gas feed pipe which is co-pressed into the body during forming thereor by isostatic pressing. The advantages of using a co-pressed coupler are that a fully integrated connection for the gas pipe is provided which is completely bonded into the body in a secure manner which minimises the possibility of gas leaks around the coupler and the surrounding refractory body can be made much thicker to provide added strength because there is no need to leave an opening for subsequent insertion of a separately formed plug as in the known product. This also means that the throughbore . - . .
" , , .
~r: .
'r,~
~'i" : ' ' ' ' ' ' ' ' 3 2(~C~87~:
present in the rotor of the known type need not be of such large diameter at the driven end of the rotor and may instead be a significantly narrower bore internal channel the length of which is a matter of choice taking into account the amount S of material required to form the shape and the strength required of the rotor. The manner of forming such a channel can be by use of void formers or similar ~eans as is already known in the art. Thus to all intents and purposes the rotor stem head is substantially solid in comparison with the known assembly. The result is an improved strength rotor which is less likely to suffer mechanical damage due to the stresses applied by the driving assembly, is less inclined to suffer gas leakage due to the omission of the cemented joints apparent in the prior art and is more easily manufactured, in ~S one step, which also results in economic advantages.
The driven end of the rotor stem may be formed by moulding and machining to have a polygonal shape suitable for receiving a corresponding drive cap forming part of a driving mechanism for turning the rotor.
According to the invention the coupler may be of thin metal, preferably the thinnest capable of fulfilling its intended purpose in order to minimise differential ther~al e~pansion probls~s, and has a shape which resists rotation during assembly to facilitate insertion of the gas pipe and resist loosening of the coupling during use o~ the rotor. Thus the coupler may comprise a female threaded barrel portion having an external surface which is adapted to resist rotation by being non-circular, having flats, or having projections or recesses which will provide an interference fit with the ?
surrounding refractory material in the pressed product.
Preferably also the coupler will have a surface coating such as boro-silicate glass or the like to provide a bond between the refractory ~aterial of the rotor stem and the coupler.
The advantages of the one piece rotor head construction of this invention are that the coupler geometry enables it to be incorporated readily in the tooling set up for pressing of the rotor body and the surface treatment of the coupler with a ~,,: - . . . .
,, - ,. . .
, . . . .
,.~ , . . . .
.i ~ . - ,, .
~ ',: :,-: , ,.-,, , . ' -20as~
_ 4 bonding agent ensures total adhesion and seal integrity between the coupler and the body o~ the rotor stem. This enables the problems associated with the prior art separate forming of ~ented plu~ insert an~ post-pressing asse~bly of s the rotor stem head, with attendant ~as leakage risks in such a multi-part head to ~e avoided. Additionally, use of such a coupler enables the material forming the rotor head to be a homogeneous reg~on without the stress raisers ~joints and artifacts) apparent in the currently available multi-part and lo multi-material rotor stem design.
The coupler may alternatively be pre-formed from a durable high strength ceramic material to provide a suitably shaped insert having an internal threaded socket for receiving a gas pipe, which insert by its nature would be readily compatible with the refractory material used in pressing the rotor stem, allowing it to be co-pressed into the body of the rotor stem to provide a head design which would also a~oid the stress raisers evident in the known design as discussed above. A
suitable ceramic material would be reaction bonded silicon nitride.
A further way of avoiding use of the separately formed vented plug arrangement involves formation of a compression joint 2s between a gas pipe and the rotor stem body which is adapted according to the invention to receive the pipe by pressing of a blend of refractory materials in a region of the driven end of the rotor stem to form in that end a tapered openïng ha~ing durable surfaces for engaging the gas pipe in a close fit arrangement, which engagement is ensured by providing a threaded portion on the exterior of the gas pipe and a corresponding thread on a cap component which is fastenable to said end of the rotor stem.
3s Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:-Fig. 1 is a longitudinal section through a rotorstem of the known type illustrating t~e cemented plug and pipe arrangement which can prove problematic ~n use;
... . . . .
I
._... , - -~, , .i: ' ~ ' ' ~,.,:, ,, :, 5 2~08~
Fig. 2 is a longitudinal section through a rotor stem according to the invention illustrating the increased end section thickness which incorporates an integral fully sealed gas coupler fitment;
Fig. 3 is an enlarged view, in section, of the end of the rotor shown in Fig. 2 illustrating one embodiment of the coupler according to this invention; and Fig. 4 is a view in section of the end of a rotor stem in accordance with this invention wherein a compression lo fitting of the gas feed pipe is provided.
In the prior art rotor stems as illustrated in Fig. 1 a rotor stem is formed by isostatic pressing from particulate refractory materials, e.g. graphitised alumina, to provide an elongate body 1 of generally columnar shape having an a~ial throughbore 2. The body 1 has a thickened end 3 with a concave surface 4 which, in use, bears upon a corresponding con~ex surface of a nozzle component (not shown) fixed in the base of a vessel (not shown) containing molten material. This thickened end has an eccentric orifice 5 in the nozzle-contacting surface 4 which is registrable with an outlet passage in the nozzle. It also has in its sidewall, an opening 6 communicating with the orifice 5 whereby, in conjunction with the passage in the nozzle, a melt flow pathway out of the vessel may be formed by controlled rotation of the rotor stem about its longitudinal axis to bring the orifice 5 into register with the passageway. Rotation of the rotor stem causes displacement of the orifice 5 so that it no longer corresponds with the passage which of course cuts off melt flow from the vessel. Such rotation of the rotor stem is accomplished by means of a drive mechanism including a drive cap 9 attachable, conveniently by a simple press fit, to the other end 10 of the rotor stem which is generally thinner than the nozzle-contacting end and machined to fit into the drive 3s mechanism. The throughbore 2 is plugged at the nozzle-contacting end 3 by a vented p~ug ? and at the other end 10 by a vented plug assembly 8 including a gas supply pipe 11.
These plugs are inserted after pressing of the rotor stem body and cemented into posit~on. Since the plug 8 is a separately ~, , ~,-, ~ ,, 6 2(~ 2 pressed article made up of a threaded pipe coupling 12, voiding materials and refractory materials it is of relatively larqe size to provide strength, this requires tbe throughbore to be of relatively large diameter. The outer diameter of the rotor stem is constrained by the need to fit the drive assembly. This means that the body thickness at She driven end 10 may represent a source of weakness which could result in reduced operational life due to mechanical stren~th failure.
, In an improved rotor ste~ design in accordance with the invention, as shown in Fig.2, the nozzle contacting end 13 of the rotor stem can be equivalent to that of the prior art. ~ -However the driven end 30 is modified to provide, in a single t 5 forming step by isostatic pressing, an integral coupling 32 for a gas pipe 31 as is more clearly sh~wn in Fig. 3. Thus the rotor stem according to this embodiment of the invention ~ ~
is formed by isostatic pressing from particulate refractory ~ ~-materials to proYide an elongate body 21 of generally columnar shape havin~ an internal gas duct 22 extending longitudinally from a thickened end 13 which has a concaYe surface 1~ for a known purpose as indicated above with a corresponding convex surface of a nozzle component (not shownl fixed in the base of a vessel ~not shown) containing molten material. Similarly 2s this thickened end has an eccentric orifice 15 in the nozzle-contacting surface 14 which is registrable with an outlet passage in the nozzle and, in its sidewall, an opening 16 communicating with the orifice 15 to define, in conjunction with the passage in the nozzle, a melt flow pathway out of the vessel when the orifice 15 is aligned with the passageway. As before rotational control over the rotor stem is accomplished by means of a drive mechanis~ including a drivs cap 19 attachable by pressing onto the other end 30 of the rotor stem which is substantially solid and formed to fit into the drive 3s mechanism. This end 30 is formed from re~ractory materials in which there is located a void former to provide a narrow bore channel 18 linking a gas supply pipe ~1 with the gas duct 22.
The gas duct 22 has a vented plug 17 and at its other end whereby controlled supply of inert gas may be passed directly ., ' ' , . :
:. , : : :
. . '; . ~, , : ~
. ' ~ : . : - ~ , , ., :
: , .
7 2(~7~
through the rotor stem in a manner generally known per se.
However the modified rotor stem according to this invention provides a more efficient way of handling the gas due to elimination of all joints evident in previous systems apart s from that between the gas pipe and the coupler. In addition the superior mechanical strength provided by the very much thicker upper end 30 provides increased operational life.
Further improvements in resistance to impact damags and thermal shock are obtained by use or a smaller diameter gas duct 22 which is accompanied by a corresponding thickness in the body around it. The duct 22 need not extend so far through the body 21 as shown in the drawing and may only be a small chamber in a lower portion of the rotor stem in which case the channel 18 will be of greater length. ~his is possible because there is no need to provide a large access aperture for receiving a vented plug and coupler assembly as in the prior art.
In a further embodiment of this invention as illustrated in Fig. ~ an improved rotor stem which is otherwise simitar to that shown in Fig. 2 has an upper end 40 including an integral vented coupler 42 formed from refractory material, preferably zirconia/alumina or reaction bonded silicon nitride or the like, which has a surface 44 adapted to receive a tapered end 2s 43 of a gas supply pipe 41 in a close fit under compression.
The upper end 40 is also shaped to receive a drive cap 39 in the crown of which there is a tapped bore 29 through which said tapered end 43 may pass to engage said surface 44. The gas supply pipe has a threaded exterior surface portion 45 for locating the pipe in the drive cap ~9 which once fixed to the rotor stem head for use forces the gas pipe 41 into engagement with the coupler surface 44 to provide a compression seal. As in the embodiment of Fig 2 a narrow bore gas channel 38 is used to convey gas from the coupler 42 through the rotor stem 3s body which may then be substantially thicker in that region tQ ~ -improve mechanical strength.
. .
Such an arrangement has advantages in simplicity of manufacture, reduction of the nu~ber of joi~ts to a single , . !
"-" ' . '', .: - ' , ''"' ' " ' , . , :~, ,:, ' ' ' ~.
,',,, -' ' - ' ' ",~,,, ,,. , . :
-,: . , , : , 2~
R
metal-ceramic joint which is ~elf closing due to the normal bearing loads on the drive cap which are required to provide good stem to nozzle contact also acting to maintain close fit ~etween the metal pipe and ceramic coupler surface.
, ~:' : ', ,,, , , : :
from an actuator mechanism to the rotor to maintain close mating surface contact with the nozzle component.
It is conventional to provide such systems with ~eans for delivering an inert gas, e.g. argon, for reasons well known in the art such as purging o air to avoid melt oxldation pro~lems. ~ncorporation ef such gas supply means is an added difficulty. ~he way that this has been done in the past is to fit in the throughbore at the driven end o~ the rotor stem a lo vented plug into which is fitted a metal pipe by a separate forming operation. The pipe and plug are cemented into position and this does not always provide a satisfactory gas-tight joint. A typical multicomponent system currently in use is shown in Fig. 1. Problems which manifest themsel~es with such an assembly include the need to provide high mechanical strength at both hot and cold temperatures, close dimensional accuracy, especially at the driven end where mating with the driving assembly is required, and the need to provide gas-tight joints to avoid undesirable losses of the expensive ~0 inert gas.
Thus such a component is not easy to manufacture and an object -of the present invention is provide improvements therein whereby such problems are obviated or mitigated.
2s Accordingly th1s invention provides a rotor stem comprising a longitudinal body, formed from refractory materials by an isostatic pressing method, having one end adapted to receive a -driving component, wherein said end contains a coupler for ~-attachment of a gas feed pipe which is co-pressed into the body during forming thereor by isostatic pressing. The advantages of using a co-pressed coupler are that a fully integrated connection for the gas pipe is provided which is completely bonded into the body in a secure manner which minimises the possibility of gas leaks around the coupler and the surrounding refractory body can be made much thicker to provide added strength because there is no need to leave an opening for subsequent insertion of a separately formed plug as in the known product. This also means that the throughbore . - . .
" , , .
~r: .
'r,~
~'i" : ' ' ' ' ' ' ' ' 3 2(~C~87~:
present in the rotor of the known type need not be of such large diameter at the driven end of the rotor and may instead be a significantly narrower bore internal channel the length of which is a matter of choice taking into account the amount S of material required to form the shape and the strength required of the rotor. The manner of forming such a channel can be by use of void formers or similar ~eans as is already known in the art. Thus to all intents and purposes the rotor stem head is substantially solid in comparison with the known assembly. The result is an improved strength rotor which is less likely to suffer mechanical damage due to the stresses applied by the driving assembly, is less inclined to suffer gas leakage due to the omission of the cemented joints apparent in the prior art and is more easily manufactured, in ~S one step, which also results in economic advantages.
The driven end of the rotor stem may be formed by moulding and machining to have a polygonal shape suitable for receiving a corresponding drive cap forming part of a driving mechanism for turning the rotor.
According to the invention the coupler may be of thin metal, preferably the thinnest capable of fulfilling its intended purpose in order to minimise differential ther~al e~pansion probls~s, and has a shape which resists rotation during assembly to facilitate insertion of the gas pipe and resist loosening of the coupling during use o~ the rotor. Thus the coupler may comprise a female threaded barrel portion having an external surface which is adapted to resist rotation by being non-circular, having flats, or having projections or recesses which will provide an interference fit with the ?
surrounding refractory material in the pressed product.
Preferably also the coupler will have a surface coating such as boro-silicate glass or the like to provide a bond between the refractory ~aterial of the rotor stem and the coupler.
The advantages of the one piece rotor head construction of this invention are that the coupler geometry enables it to be incorporated readily in the tooling set up for pressing of the rotor body and the surface treatment of the coupler with a ~,,: - . . . .
,, - ,. . .
, . . . .
,.~ , . . . .
.i ~ . - ,, .
~ ',: :,-: , ,.-,, , . ' -20as~
_ 4 bonding agent ensures total adhesion and seal integrity between the coupler and the body o~ the rotor stem. This enables the problems associated with the prior art separate forming of ~ented plu~ insert an~ post-pressing asse~bly of s the rotor stem head, with attendant ~as leakage risks in such a multi-part head to ~e avoided. Additionally, use of such a coupler enables the material forming the rotor head to be a homogeneous reg~on without the stress raisers ~joints and artifacts) apparent in the currently available multi-part and lo multi-material rotor stem design.
The coupler may alternatively be pre-formed from a durable high strength ceramic material to provide a suitably shaped insert having an internal threaded socket for receiving a gas pipe, which insert by its nature would be readily compatible with the refractory material used in pressing the rotor stem, allowing it to be co-pressed into the body of the rotor stem to provide a head design which would also a~oid the stress raisers evident in the known design as discussed above. A
suitable ceramic material would be reaction bonded silicon nitride.
A further way of avoiding use of the separately formed vented plug arrangement involves formation of a compression joint 2s between a gas pipe and the rotor stem body which is adapted according to the invention to receive the pipe by pressing of a blend of refractory materials in a region of the driven end of the rotor stem to form in that end a tapered openïng ha~ing durable surfaces for engaging the gas pipe in a close fit arrangement, which engagement is ensured by providing a threaded portion on the exterior of the gas pipe and a corresponding thread on a cap component which is fastenable to said end of the rotor stem.
3s Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:-Fig. 1 is a longitudinal section through a rotorstem of the known type illustrating t~e cemented plug and pipe arrangement which can prove problematic ~n use;
... . . . .
I
._... , - -~, , .i: ' ~ ' ' ~,.,:, ,, :, 5 2~08~
Fig. 2 is a longitudinal section through a rotor stem according to the invention illustrating the increased end section thickness which incorporates an integral fully sealed gas coupler fitment;
Fig. 3 is an enlarged view, in section, of the end of the rotor shown in Fig. 2 illustrating one embodiment of the coupler according to this invention; and Fig. 4 is a view in section of the end of a rotor stem in accordance with this invention wherein a compression lo fitting of the gas feed pipe is provided.
In the prior art rotor stems as illustrated in Fig. 1 a rotor stem is formed by isostatic pressing from particulate refractory materials, e.g. graphitised alumina, to provide an elongate body 1 of generally columnar shape having an a~ial throughbore 2. The body 1 has a thickened end 3 with a concave surface 4 which, in use, bears upon a corresponding con~ex surface of a nozzle component (not shown) fixed in the base of a vessel (not shown) containing molten material. This thickened end has an eccentric orifice 5 in the nozzle-contacting surface 4 which is registrable with an outlet passage in the nozzle. It also has in its sidewall, an opening 6 communicating with the orifice 5 whereby, in conjunction with the passage in the nozzle, a melt flow pathway out of the vessel may be formed by controlled rotation of the rotor stem about its longitudinal axis to bring the orifice 5 into register with the passageway. Rotation of the rotor stem causes displacement of the orifice 5 so that it no longer corresponds with the passage which of course cuts off melt flow from the vessel. Such rotation of the rotor stem is accomplished by means of a drive mechanism including a drive cap 9 attachable, conveniently by a simple press fit, to the other end 10 of the rotor stem which is generally thinner than the nozzle-contacting end and machined to fit into the drive 3s mechanism. The throughbore 2 is plugged at the nozzle-contacting end 3 by a vented p~ug ? and at the other end 10 by a vented plug assembly 8 including a gas supply pipe 11.
These plugs are inserted after pressing of the rotor stem body and cemented into posit~on. Since the plug 8 is a separately ~, , ~,-, ~ ,, 6 2(~ 2 pressed article made up of a threaded pipe coupling 12, voiding materials and refractory materials it is of relatively larqe size to provide strength, this requires tbe throughbore to be of relatively large diameter. The outer diameter of the rotor stem is constrained by the need to fit the drive assembly. This means that the body thickness at She driven end 10 may represent a source of weakness which could result in reduced operational life due to mechanical stren~th failure.
, In an improved rotor ste~ design in accordance with the invention, as shown in Fig.2, the nozzle contacting end 13 of the rotor stem can be equivalent to that of the prior art. ~ -However the driven end 30 is modified to provide, in a single t 5 forming step by isostatic pressing, an integral coupling 32 for a gas pipe 31 as is more clearly sh~wn in Fig. 3. Thus the rotor stem according to this embodiment of the invention ~ ~
is formed by isostatic pressing from particulate refractory ~ ~-materials to proYide an elongate body 21 of generally columnar shape havin~ an internal gas duct 22 extending longitudinally from a thickened end 13 which has a concaYe surface 1~ for a known purpose as indicated above with a corresponding convex surface of a nozzle component (not shownl fixed in the base of a vessel ~not shown) containing molten material. Similarly 2s this thickened end has an eccentric orifice 15 in the nozzle-contacting surface 14 which is registrable with an outlet passage in the nozzle and, in its sidewall, an opening 16 communicating with the orifice 15 to define, in conjunction with the passage in the nozzle, a melt flow pathway out of the vessel when the orifice 15 is aligned with the passageway. As before rotational control over the rotor stem is accomplished by means of a drive mechanis~ including a drivs cap 19 attachable by pressing onto the other end 30 of the rotor stem which is substantially solid and formed to fit into the drive 3s mechanism. This end 30 is formed from re~ractory materials in which there is located a void former to provide a narrow bore channel 18 linking a gas supply pipe ~1 with the gas duct 22.
The gas duct 22 has a vented plug 17 and at its other end whereby controlled supply of inert gas may be passed directly ., ' ' , . :
:. , : : :
. . '; . ~, , : ~
. ' ~ : . : - ~ , , ., :
: , .
7 2(~7~
through the rotor stem in a manner generally known per se.
However the modified rotor stem according to this invention provides a more efficient way of handling the gas due to elimination of all joints evident in previous systems apart s from that between the gas pipe and the coupler. In addition the superior mechanical strength provided by the very much thicker upper end 30 provides increased operational life.
Further improvements in resistance to impact damags and thermal shock are obtained by use or a smaller diameter gas duct 22 which is accompanied by a corresponding thickness in the body around it. The duct 22 need not extend so far through the body 21 as shown in the drawing and may only be a small chamber in a lower portion of the rotor stem in which case the channel 18 will be of greater length. ~his is possible because there is no need to provide a large access aperture for receiving a vented plug and coupler assembly as in the prior art.
In a further embodiment of this invention as illustrated in Fig. ~ an improved rotor stem which is otherwise simitar to that shown in Fig. 2 has an upper end 40 including an integral vented coupler 42 formed from refractory material, preferably zirconia/alumina or reaction bonded silicon nitride or the like, which has a surface 44 adapted to receive a tapered end 2s 43 of a gas supply pipe 41 in a close fit under compression.
The upper end 40 is also shaped to receive a drive cap 39 in the crown of which there is a tapped bore 29 through which said tapered end 43 may pass to engage said surface 44. The gas supply pipe has a threaded exterior surface portion 45 for locating the pipe in the drive cap ~9 which once fixed to the rotor stem head for use forces the gas pipe 41 into engagement with the coupler surface 44 to provide a compression seal. As in the embodiment of Fig 2 a narrow bore gas channel 38 is used to convey gas from the coupler 42 through the rotor stem 3s body which may then be substantially thicker in that region tQ ~ -improve mechanical strength.
. .
Such an arrangement has advantages in simplicity of manufacture, reduction of the nu~ber of joi~ts to a single , . !
"-" ' . '', .: - ' , ''"' ' " ' , . , :~, ,:, ' ' ' ~.
,',,, -' ' - ' ' ",~,,, ,,. , . :
-,: . , , : , 2~
R
metal-ceramic joint which is ~elf closing due to the normal bearing loads on the drive cap which are required to provide good stem to nozzle contact also acting to maintain close fit ~etween the metal pipe and ceramic coupler surface.
, ~:' : ', ,,, , , : :
Claims (7)
1. A rotor stem comprising a longitudinal body, formed from refractory materials by an isostatic pressing method, having one end adapted to receive a driving component, wherein said end contains, for attachment of a gas feed pipe, a coupler which is co-pressed into the body during forming thereof by isostatic pressing.
2. A rotor stem according to claim 1 wherein the co-pressed coupler is formed of thin metal or from high strength ceramic material.
3. A rotor stem according to claim 1 or claim 2 wherein the coupler has a shape which resists rotation thereof within the stem during insertion of the gas pipe and resists loosening of the coupler during use of the rotor.
4. A rotor stem according to claim 3 wherein the coupler comprises a female threaded barrel portion having an external surface which is adapted to resist rotation by being non-circular, having flats, projections or recesses which provide an interference fit with the surrounding refractory material in the final pressed product.
5. A rotor stem according to claim 2 or claim 3 wherein a blend of refractory materials is pressed in a region of the driven end of the rotor stem to form in that end a tapered opening having durable surfaces for engaging the gas pipe in a close fit arrangement, which end further has a threaded portion upon which a correspondingly threaded cap component connected to the gas pipe is fastenable to said end of the rotor stem whereby the gas pipe is urged into said close fit arrangement.
6. A rotor stem according to any one of claims 1 to 5 wherein the coupler has a surface coating of a boro-silicate glass or the like to provide a bond between the refractory material of the rotor stem and the coupler.
7. A rotor stem substantially as hereinbefore described with reference to Figs. 2 and 3 or Fig. 4 of the accompanying drawings
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8901683.6 | 1989-01-26 | ||
| GB8901683A GB2228222A (en) | 1989-01-26 | 1989-01-26 | Rotor for molten material discharge control valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2008742A1 true CA2008742A1 (en) | 1990-07-26 |
Family
ID=10650621
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002008742A Abandoned CA2008742A1 (en) | 1989-01-26 | 1990-01-26 | Rotor |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA2008742A1 (en) |
| GB (1) | GB2228222A (en) |
| WO (1) | WO1990008611A1 (en) |
| ZA (1) | ZA90583B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4442336A1 (en) * | 1994-11-29 | 1996-05-30 | Didier Werke Ag | Closing and / or regulating element for a metallurgical vessel |
| DE19823988C2 (en) * | 1998-05-29 | 2000-07-20 | Didier Werke Ag | Stopper for the closure of containers holding molten metal |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2120369A (en) * | 1982-05-20 | 1983-11-30 | Ksr Int Ltd | An improved metallurgical lance |
| AU591889B2 (en) * | 1985-03-26 | 1989-12-21 | British Steel Plc | Improvements in or relating to outlet valves for metal containing vessels |
| DE3511772A1 (en) * | 1985-03-30 | 1986-10-09 | Didier-Werke Ag, 6200 Wiesbaden | Blowing lance |
| GB2210305A (en) * | 1987-10-02 | 1989-06-07 | Thor Ceramics Ltd | Refractory monoblock stopper |
| US4946083A (en) * | 1988-12-29 | 1990-08-07 | Vesuvius Crucible Company | One-piece stopper rod |
-
1989
- 1989-01-26 GB GB8901683A patent/GB2228222A/en not_active Withdrawn
-
1990
- 1990-01-26 CA CA002008742A patent/CA2008742A1/en not_active Abandoned
- 1990-01-26 ZA ZA90583A patent/ZA90583B/en unknown
- 1990-01-26 WO PCT/GB1990/000112 patent/WO1990008611A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| GB2228222A (en) | 1990-08-22 |
| WO1990008611A1 (en) | 1990-08-09 |
| GB8901683D0 (en) | 1989-03-15 |
| ZA90583B (en) | 1990-10-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4630802A (en) | Nozzle for injection lance | |
| CA2639194A1 (en) | Coupling for a molten metal processing system | |
| JPS61259869A (en) | Outlet valve for vessel | |
| GB2213412A (en) | Refractory valve plate for sliding gate valve | |
| CA2008742A1 (en) | Rotor | |
| KR100585977B1 (en) | Stopper rod | |
| US4091971A (en) | Molten metal nozzle having capillary gas feed | |
| EP0346378B1 (en) | Tubular refractory product | |
| US5983979A (en) | Hot chamber die casting machine for aluminum and its alloys | |
| US6478201B2 (en) | Stopper for continuous casting | |
| US5866022A (en) | Refractory pour tube with cast plate | |
| JP2778947B2 (en) | Refractory plate assembly for stationary plate of sliding gate valve | |
| US5072778A (en) | Casting vessel for hot-chamber pressure diecasting machines | |
| GB2247637A (en) | Stoppers for use in molten metal handling | |
| US5681497A (en) | Arrangement for connecting a stopper rod for a metallurgical vessel with a lifting device, suitable stopper rod for the arrangement and process for producing the arrangement | |
| JP4402837B2 (en) | Fireproof nozzle | |
| US5099907A (en) | Apparatus and method for the connection of a new cast strip in a continuous casting operation | |
| CA2311907A1 (en) | Stopper rod | |
| US5310098A (en) | Bush for directing a stream of molten metal into a mold | |
| US4718580A (en) | Structure for forming a refractory joint of predetermined thickness between a refractory nozzle and a refractory plate | |
| GB2153977A (en) | Sliding gate valves | |
| US5392842A (en) | Casting metals | |
| JPH0320098Y2 (en) | ||
| JP2005088017A (en) | Composite sleeve for die casting machine | |
| JPH07100602A (en) | Method for sealing dummy bar in continuous casting mold and dummy bar head |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |