CA1187696A - Valve plates for a sliding gate valve - Google Patents
Valve plates for a sliding gate valveInfo
- Publication number
- CA1187696A CA1187696A CA000386469A CA386469A CA1187696A CA 1187696 A CA1187696 A CA 1187696A CA 000386469 A CA000386469 A CA 000386469A CA 386469 A CA386469 A CA 386469A CA 1187696 A CA1187696 A CA 1187696A
- Authority
- CA
- Canada
- Prior art keywords
- sliding
- wall surfaces
- opening
- plates
- improvement
- 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.)
- Expired
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
- B22D41/22—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings
- B22D41/26—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings characterised by a rotatively movable plate
-
- 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
- B22D41/22—Closures sliding-gate type, i.e. having a fixed plate and a movable plate in sliding contact with each other for selective registry of their openings
- B22D41/28—Plates therefor
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Sliding Valves (AREA)
Abstract
ABSTRACT
A pair of valve plates for a sliding gate valve each have a sliding surface which, in use, slide relative to one another and a discharge aperture which passes through the plate and opens onto the sliding surface. Each aper-ture is defined by two wail sections which extend perpendicular to the intended direction of relative displacement of the sliding surfaces and two wall sections which extend parallel to the said direction of displacement. This results in the length of the edges of the apertures which is exposed to the melt being re-duced and any metal which solidifies between the plates being capable of being pushed into the apertures by relative movement of the plates.
A pair of valve plates for a sliding gate valve each have a sliding surface which, in use, slide relative to one another and a discharge aperture which passes through the plate and opens onto the sliding surface. Each aper-ture is defined by two wail sections which extend perpendicular to the intended direction of relative displacement of the sliding surfaces and two wall sections which extend parallel to the said direction of displacement. This results in the length of the edges of the apertures which is exposed to the melt being re-duced and any metal which solidifies between the plates being capable of being pushed into the apertures by relative movement of the plates.
Description
~'7~
This invention relates to a pair of valve plates for a sliding gate valve and to a sliding gate valve incorporating such plates. Such plates have a sliding surface which, in use, slides relative to the sliding surface of the other plate and are used to control the flow of mol~en metals.
It is known that, during the regulated discharge of metals, especi-ally steel, the plates of sliding gate valves are subjected to severe wear des-pite the use of high-grade refractory materials. The apertures in the plates and the attached refrac~ory parts undergo continuous widening of their cross-sectional area, caused by the melt flowing out. What is much more serious, however, is that in the in~ermediate positions of the gate valve, that is to sa~
during opening and closing of the valve and during throttled pouring, parts of ~he edges of the apertures and adjoining regions of the sliding s-urfaces are exposed ~o the flowing melt and are particularly severely attacked because the discharge channel narrows there. This situation has been known for a lonx time, ~nd is described in e.g. Swiss Patent No. 528942, Figures 2 and 3, and as a rule determines the number of pourings which can be carried out with one se~ of plates, because the continuing erosion of the sliding surfaces in the said re-gions finally renders a sealed closure impossible, whereupon the plates must be replaced. Inspection of the installed plates after each casting to determine whether the degree o wear will permit further reliable use is no~ very easy because of the restricted view of the sliding surfaces and requires a certain experience~
In order to reduce th0 wear on the ed~es referred to above a stepped widening of at least one of the discharge apertures towards the sliding surface has been proposed in German Offenlegungsschrif~ No. ~01~331. ~lowever, for a given bore diameter this implies a considerable lengthening of the path between the open and closed positions and a reduced overlap of the plates a~ right angles to the direction of relative displaccment. Therefore, this proposal can only be put in-to practice with a relcl-tive increase ln the size of the plate surfaces and thus of the whole valve.
It has been further proposed, in German Offenlegungs shrift No. 1937742, tha-t the sliding plate be provided with a special liner made from heat-proof metallic hard material, e.g.
a metal ceramic solid solution, along the discharge aperture and on the sliding surface in order to protect the points which are subject to wear. However, the varying coefficients of thermal expansion of the liner material and the backing material lead -to problems, and the production of such plates is naturally substantially more expensive.
By contrast, an object of the present invention is the reduction and bet-ter control of the wear occurring on the valve plates, or the effec-ts thereof, without having to accept -the considerable disadvantages attached to the known proposals.
According to the present inven-tion there is provided in a sliding closure unit for regulating a stream of molten metal discharged from a metallurgical vessel and including an upstream stationary plate adapted to be moun-ted in fixed relation-ship with respect to the metallurgical vessel and having there-through a flow-through opening, and a downstream sliding plate in abutti.ng contact with said stationary plate and having there-through at least one flow-throuyh opening -to be selectively moved into and out of alignment with said flow-through opening of said stationary plate upon movernent of said sli.ding pla-te in a direction of movement with respec-t to said stationary plate, said stationary and sliding plates consisting of refractory material and having abutting rela-tive slidiny surEaces subjec-t to erosi.on ,j J - 2-!~ ' adjacent to said flow-throuyh openings by said stream of molten metal, the improvement comprising:
means for reducing erosion damage to edges of said flow-through openings, at least in the areas thereof opening into said sliding surfaces, said means comprising a construction such that each said flow-through opening is defined, at least in the area thereof that opens onto the respective said sliding surface, by two planar wall surfaces which extend at equal angles across said direction of movement and by two other wall surfaces which are connected to ends of said planar wall surfaces and extend in directions parallel to said direction of movement.
Valve plates according to the invention can be produced in a simple manner but without a significant increase in cost by comparison with conventional plates having circular discharge apertures. This can be done, for example, by pressing a corresponding die or core around in the same operation in which the plates are given their rough shape. The principal advantage of the inven--2a-~'7~Y3~
tion ls -that by comparison with round discharge apertures smaller and better formed wear surfaces are produced on the sliding surfaces of the plates~ as will be described in greater detail below. In addition the edge portions, which are exposed to the flow of the melt in the intermediate positions of the gate valve, are always the same size and on average shorter than with a round discharge aperture.
Although in the past valve plates have, in practice, been used ex-clusively with circular discharge apertures, ~here have been isolated proposals for non-circular aperture cross-sections, e.g. in ~erman Offenlegungsschrift No. 1910247 and German Auslegeschrift No. ~006523. The main object of ~hese was to achieve a particular regulating characteristic ~aperture cross-section as a function of the displacement path), whilst the problem of the wear on the edges, which underlies the present invention, still remained.
The first and second wall sections preferably all touch an imaginary inscribed circle, but in a modified construction the first wall sections lie outside this circle. The cross-section of the apertures may be constant over the thickness of the plates or it may change over the thickness of the plates so as to be, e.g., circular on the sides of the plates remote from the sliding sur-faces.
The invention also embraces a sliding gate valve incorporating such a pair of plates. It will be appreciated tha~ for a rotary valve the discharge apertures will be part-annular, that is to say their shape is that of a sector of an annulus, and for a linear valve their shape is a parallelogram and may be a square or rectanglo.
~urther Eeatures and details of the invention will be apparent Erom the following description of certain known constructions and of certain con-structions in accordance with the present invention, which description is given by way of e~.a~ple only, with reference to the accompanying drawings in which:-Figures 1 and 2 are schematic vertical sections thrsugh a pair of plates for a ro~ary and linear sliding gate valve, respectively, showing their general cons~ruction;
Figure 3 is a diagrammatic scrap plan view showing the conskruction-al proportions in a rotary gate valve of known construction with circular dis-charge apertures;
Figure 4 is a view similar to Figure 3 showing a pair of valve plates according to a first embodiment of the invention;
Figure 5 is a scrap perspective view of the plates of Figure ~ in the throttled position;
Figure 6 shows a preferred geometric form of the aper~ure cross-section in the plates of Figures ~ and 5;
Figure 7 is a plan view of a further embodiment of a pair of valve plates in~ended for use in a linear sliding gate valve; and Figures 8 and 9 show further variants of aperture cross-sections in a pair of valve plates according to the invention for a linear sliding gate valve.
Figure 1 shows the two valve plates of a rotary sliding gate valve comprising an upper stationary base plate 1 and a sliding plate 2, which is ro-ZO tatable about the central axis 3 as indicated by the arrow 10. Each plate is provided with at least one discharge aperture 5, 6; the sliding plate 2 can, as is ~nown, have several discharge apertures wikh the same or different cross-sections. The valve plates are made from high-grade refractory material and come into contaot with each other on their sliding surface ~, a:long which they move relative to each other when the valve is operated. The plates may be in the open position in which the discharge apertures are al:igned with each other, the throttled position, in which the apertures are partially ofset and the closed position, in whicn the apertures are completely offset. The generally _~_ '7~6 sleeve-like refractory parts 7 and 8, which are connected to the valve plates at the top and bottom and together with the discharge apertures form a pouring channel, are indicated by chain dotted lines.
Figure 2 shows the corresponding situation in a linear sliding gate valve with a stationary base plate 11 and a movable sliding plate 12. The lat-ter is movable along the sliding surfaces 1~ in the direction of the arrow 13 in order to bring the discharge apertures 15, 16 out of the illustra~ed closed position into the open position or a throttled position. As in the case of ~he rotary valve ~he sliding plate can be provided in a known manner with several discharge apertures offset in the sliding-direction. The refractory casings 17 and 18 which are connected to the plates at the top and bottom are again indi-cated by chain dotted lines.
The general constructions described with reference to Figures 1 and
This invention relates to a pair of valve plates for a sliding gate valve and to a sliding gate valve incorporating such plates. Such plates have a sliding surface which, in use, slides relative to the sliding surface of the other plate and are used to control the flow of mol~en metals.
It is known that, during the regulated discharge of metals, especi-ally steel, the plates of sliding gate valves are subjected to severe wear des-pite the use of high-grade refractory materials. The apertures in the plates and the attached refrac~ory parts undergo continuous widening of their cross-sectional area, caused by the melt flowing out. What is much more serious, however, is that in the in~ermediate positions of the gate valve, that is to sa~
during opening and closing of the valve and during throttled pouring, parts of ~he edges of the apertures and adjoining regions of the sliding s-urfaces are exposed ~o the flowing melt and are particularly severely attacked because the discharge channel narrows there. This situation has been known for a lonx time, ~nd is described in e.g. Swiss Patent No. 528942, Figures 2 and 3, and as a rule determines the number of pourings which can be carried out with one se~ of plates, because the continuing erosion of the sliding surfaces in the said re-gions finally renders a sealed closure impossible, whereupon the plates must be replaced. Inspection of the installed plates after each casting to determine whether the degree o wear will permit further reliable use is no~ very easy because of the restricted view of the sliding surfaces and requires a certain experience~
In order to reduce th0 wear on the ed~es referred to above a stepped widening of at least one of the discharge apertures towards the sliding surface has been proposed in German Offenlegungsschrif~ No. ~01~331. ~lowever, for a given bore diameter this implies a considerable lengthening of the path between the open and closed positions and a reduced overlap of the plates a~ right angles to the direction of relative displaccment. Therefore, this proposal can only be put in-to practice with a relcl-tive increase ln the size of the plate surfaces and thus of the whole valve.
It has been further proposed, in German Offenlegungs shrift No. 1937742, tha-t the sliding plate be provided with a special liner made from heat-proof metallic hard material, e.g.
a metal ceramic solid solution, along the discharge aperture and on the sliding surface in order to protect the points which are subject to wear. However, the varying coefficients of thermal expansion of the liner material and the backing material lead -to problems, and the production of such plates is naturally substantially more expensive.
By contrast, an object of the present invention is the reduction and bet-ter control of the wear occurring on the valve plates, or the effec-ts thereof, without having to accept -the considerable disadvantages attached to the known proposals.
According to the present inven-tion there is provided in a sliding closure unit for regulating a stream of molten metal discharged from a metallurgical vessel and including an upstream stationary plate adapted to be moun-ted in fixed relation-ship with respect to the metallurgical vessel and having there-through a flow-through opening, and a downstream sliding plate in abutti.ng contact with said stationary plate and having there-through at least one flow-throuyh opening -to be selectively moved into and out of alignment with said flow-through opening of said stationary plate upon movernent of said sli.ding pla-te in a direction of movement with respec-t to said stationary plate, said stationary and sliding plates consisting of refractory material and having abutting rela-tive slidiny surEaces subjec-t to erosi.on ,j J - 2-!~ ' adjacent to said flow-throuyh openings by said stream of molten metal, the improvement comprising:
means for reducing erosion damage to edges of said flow-through openings, at least in the areas thereof opening into said sliding surfaces, said means comprising a construction such that each said flow-through opening is defined, at least in the area thereof that opens onto the respective said sliding surface, by two planar wall surfaces which extend at equal angles across said direction of movement and by two other wall surfaces which are connected to ends of said planar wall surfaces and extend in directions parallel to said direction of movement.
Valve plates according to the invention can be produced in a simple manner but without a significant increase in cost by comparison with conventional plates having circular discharge apertures. This can be done, for example, by pressing a corresponding die or core around in the same operation in which the plates are given their rough shape. The principal advantage of the inven--2a-~'7~Y3~
tion ls -that by comparison with round discharge apertures smaller and better formed wear surfaces are produced on the sliding surfaces of the plates~ as will be described in greater detail below. In addition the edge portions, which are exposed to the flow of the melt in the intermediate positions of the gate valve, are always the same size and on average shorter than with a round discharge aperture.
Although in the past valve plates have, in practice, been used ex-clusively with circular discharge apertures, ~here have been isolated proposals for non-circular aperture cross-sections, e.g. in ~erman Offenlegungsschrift No. 1910247 and German Auslegeschrift No. ~006523. The main object of ~hese was to achieve a particular regulating characteristic ~aperture cross-section as a function of the displacement path), whilst the problem of the wear on the edges, which underlies the present invention, still remained.
The first and second wall sections preferably all touch an imaginary inscribed circle, but in a modified construction the first wall sections lie outside this circle. The cross-section of the apertures may be constant over the thickness of the plates or it may change over the thickness of the plates so as to be, e.g., circular on the sides of the plates remote from the sliding sur-faces.
The invention also embraces a sliding gate valve incorporating such a pair of plates. It will be appreciated tha~ for a rotary valve the discharge apertures will be part-annular, that is to say their shape is that of a sector of an annulus, and for a linear valve their shape is a parallelogram and may be a square or rectanglo.
~urther Eeatures and details of the invention will be apparent Erom the following description of certain known constructions and of certain con-structions in accordance with the present invention, which description is given by way of e~.a~ple only, with reference to the accompanying drawings in which:-Figures 1 and 2 are schematic vertical sections thrsugh a pair of plates for a ro~ary and linear sliding gate valve, respectively, showing their general cons~ruction;
Figure 3 is a diagrammatic scrap plan view showing the conskruction-al proportions in a rotary gate valve of known construction with circular dis-charge apertures;
Figure 4 is a view similar to Figure 3 showing a pair of valve plates according to a first embodiment of the invention;
Figure 5 is a scrap perspective view of the plates of Figure ~ in the throttled position;
Figure 6 shows a preferred geometric form of the aper~ure cross-section in the plates of Figures ~ and 5;
Figure 7 is a plan view of a further embodiment of a pair of valve plates in~ended for use in a linear sliding gate valve; and Figures 8 and 9 show further variants of aperture cross-sections in a pair of valve plates according to the invention for a linear sliding gate valve.
Figure 1 shows the two valve plates of a rotary sliding gate valve comprising an upper stationary base plate 1 and a sliding plate 2, which is ro-ZO tatable about the central axis 3 as indicated by the arrow 10. Each plate is provided with at least one discharge aperture 5, 6; the sliding plate 2 can, as is ~nown, have several discharge apertures wikh the same or different cross-sections. The valve plates are made from high-grade refractory material and come into contaot with each other on their sliding surface ~, a:long which they move relative to each other when the valve is operated. The plates may be in the open position in which the discharge apertures are al:igned with each other, the throttled position, in which the apertures are partially ofset and the closed position, in whicn the apertures are completely offset. The generally _~_ '7~6 sleeve-like refractory parts 7 and 8, which are connected to the valve plates at the top and bottom and together with the discharge apertures form a pouring channel, are indicated by chain dotted lines.
Figure 2 shows the corresponding situation in a linear sliding gate valve with a stationary base plate 11 and a movable sliding plate 12. The lat-ter is movable along the sliding surfaces 1~ in the direction of the arrow 13 in order to bring the discharge apertures 15, 16 out of the illustra~ed closed position into the open position or a throttled position. As in the case of ~he rotary valve ~he sliding plate can be provided in a known manner with several discharge apertures offset in the sliding-direction. The refractory casings 17 and 18 which are connected to the plates at the top and bottom are again indi-cated by chain dotted lines.
The general constructions described with reference to Figures 1 and
2 apply both to known pairs of plates for rotary or linear sliding gate valves and to plates in accordance with the present invention. ~igure 3 shows the sit-uation as regards the wear on the plates 1, 2 in a ro~ary sliding gate valve of known construction, namely with discharge apertures 5 and 6 of circular cross-section. The two plates are shown in the closed position, in which the aperture 6 of the sliding plate is offset relative to the aperture 5 in the base pla~e by a distance which ensures a tight seal. In operation, the circular edges of the apertures in the region of the sealing surfaces are subjected to the great-est wear on those parts of bot}l apertures which are directed towards one another bacause these edge parts are exposed to the flowing melt from the very beginning when the valve is opened to the very end when it is closed. ~xperience has shown that this severe wear at the edges occurs over about half the circumfer-ence of the hole. In addition the adjoinincu regions of the sliding surfaces on both plates are increasingly attacked by the melt. ~s a reswlt melt can be drawn in between the two valve plates during the closure movement and these ~'7~
small quantities of melt tend to solidify rapidly. Recent observations and tests have confirmed in fact that "metal lumps" of the approximate shape of the cross-hatched area 2~ in Figure 3 are formed between the plates. Naturally, such "metal lumps" or "wedges" constitute a considerable obstacle between the plates on the next opening movement as they cannot be pushed aside between the sliding surfaces, nor can they be pushed into the aperture 6 of the sliding plate due to their shape. The process is repeated and intensified with every operation of ~he valve and the increasing damage to the sliding surfaces makes an ever increasing overlap of the plates necessary until finally the pla~es are unusable.
This strong material abrasion caused by metal solidified between the plates can in many cases end the useful life of the plates much earlier than the erosion resulting from the flowing melt. The inve~tion cou~teracts this tendency by the particular configuration of the cross-section of the aper-tures in both valve plates.
Figures 4 and 5 show a first embodiment of a pair of valve plates according to the invention for use in a rotary sliding gate valve. The plates 1 and 2 have identical discharge apertures 5' and 6' respectively. Each of the apertures is defined by two straight wall sections 21 which intersect the di-rection of relative displacemen~, indicated by the arc 10, at right angles, and by two further wall sections 22 which connect the ends of th0 wall sections 21 and extend in the direction of displacement. In a rotary valve the direction of displacement a~ any point is tangent:ial, so that a wall section extending "in the direction of ~isplacement" constitutes a part-cylindrical surface and a wall section "intersecting the direction of displacement at right--angles" con-stitutes a radially extending planar surface. The aperture cross-section in valve plates for a rotary valve thus corresponds to a sector of an ~mnulus. In accordance with the invention, this aperture cross-section must occur in the region where ~he discharge aperture opens onto the sliding surface 4. As can be seen in Figure 5, the cross-section can retain the same shape over the whole thickn0ss of the pla~e or, alterna~ively ~.ay change towards the opposite side of the plate~ for example into a circular shape.
The advantages of the cross-sectional shape of the discharge aper-tures 5' and 6' according to the invention may be seen in Figures ~ and 5 by comparison with Figure 3. When pouring in the throttled position (Figure 5), only the straight working edges of the opposed radial wall sections 21 and the adjoining surface regions 25 of the sliding surfaces 4 (Figure 5) are exposed to the melt, whilst all other edge regions, i.e. approximately three-quarters of the periphery are always covered. The adjoining eroded regions 25 of the sliding surfaces 4 are ~herefore much smaller than the corresponding surfaces 26 in the case of the known round discharge openings (Figure 3). What is even more important is that in the closed position ~Figure ~) the solidiied "metal parts" or "tongues" formed in the region 25 have such a shape that when the valve is next opened they do not jam between ~he plates but are easily pushed out into the flow channel without causing damage. For the purpose o proper comparison of the surface regions 25 and 26, Figures 3 and 4 are based on aper-ture cross-sections of the same size si~uated on the same mean radius wi~h the same minimum distance of overlap. Figure 5 also shows ~ha~, wh0n pouring is completed, the extent of the wear along the working edg0s and the adjacent sur-face regions can be very easily observed from the outside ~in an in~ermedia~e position of the apertures roughly as shown in Figure 5), which is not so 0asy with round apertures.
Figure 6 shows the preferred geometrical relationship of the various walls of the aperturc cross-section. A balanced ratio bctween ~he width ~in the radial dire~tion) and length (in the direction of displacement) of th0 aper ture cross-section 5', or 6', is produced when all the wall sections touch an 7~36 imaginary inscribed circle 2~, as shown in Figure 6. It is~ however~ also pos-sible to deviate from this rule of "inscribed circle contact," in the choice of the aperture length, ~hus, for example, the apertures of the base plate and the sliding plate can have a greater bu~ equal length or the sliding plate can have several apertures with differing lengths; advantageously, however the width of the co-operating apertures in the base plate and the sliding plate are always chosen the same and naturally on the same radius so that the edges of the wall sections 22 are never directly exposed to the melt.
By way ~f comparison Figure 6 shows a circular cross-section ~ with the same area as thQt of *he aperture shaped in accordance with the invention.
It will be seen that the displacement path Sl between the open and closed po-sition for the plates according to the invention is shorter than the correspond-ing displacement path S for plates with apertures of circular cross-section.
In addition the radial width of the area 5' according to the invention is small-er than that of the area 5 of the same cross-sectional area which maXes it pos-ible for the apertures in the plates of the present invention to be positioned so as to have a greater mean radius.
Figures 7 to 9 show embodiments of valve plates for a linear sliding gate valve in accordance with the invention. Figure 7 shows a pair of valve plates 11, 12 in the closed position and having a discharge aperture 15' or 16', respectively arranged on the central axis which extends parallel to the direction of displacement 13~ Each of the discharge-~'apertures is defined by two wall sec-tions 31 intersecting the direction of displacemen~ at right angles and two further wall sections 32 which extend in the direction of displac~ment and con-nect the two ends of the wall sections 31. In t'he preferred embodiment shown in Figure 7 the aperture cross-section is a square, i.e. all the wall sections contact an imaginary inscribed circle and the length o-f the aperture is equal to its width.
t7~3~
All the statements made above in connection with ~igures 3 to 6 in relation to the proportions in the rotary gate valve, and in particular the op-eration of the construction shown in ~igures 4 and 5 in comparison with valve plates with circular discharge apertures, also apply by analogy to valve plates ~or a linear sliding gate valve. This results from the ~act that a rotary move-ment with an inEinitely large notional rotational radius is in fact a linear movement.
Figure 8 shows a modi~ied construction in which the wall sections 33 intersect the direc~ion o~ displacement not at right angles but at an obtuse angle, although still at the same angle. In the case of a linear gate valve the wall sections 32 and 33 then form an obtuse angled parallelogram ~rhombus and rhomboid). This construc~ion is also applicable by analogy to the discharge apertures in valve plates for a rotary sliding gate valve.
Finally, Figure 9 shows a construction in which the wall sections 31 are conn0cted by two longer wall sections 34 extending in the direction of displacement. The rectangular cross-section thus formed corresponds to the con-struction in which the apertures constitute a sector of an annulus with a great-er length relative to the construction in which the walls contact an inscribed circle, as already described in connection with the rotary sliding gate valve.
small quantities of melt tend to solidify rapidly. Recent observations and tests have confirmed in fact that "metal lumps" of the approximate shape of the cross-hatched area 2~ in Figure 3 are formed between the plates. Naturally, such "metal lumps" or "wedges" constitute a considerable obstacle between the plates on the next opening movement as they cannot be pushed aside between the sliding surfaces, nor can they be pushed into the aperture 6 of the sliding plate due to their shape. The process is repeated and intensified with every operation of ~he valve and the increasing damage to the sliding surfaces makes an ever increasing overlap of the plates necessary until finally the pla~es are unusable.
This strong material abrasion caused by metal solidified between the plates can in many cases end the useful life of the plates much earlier than the erosion resulting from the flowing melt. The inve~tion cou~teracts this tendency by the particular configuration of the cross-section of the aper-tures in both valve plates.
Figures 4 and 5 show a first embodiment of a pair of valve plates according to the invention for use in a rotary sliding gate valve. The plates 1 and 2 have identical discharge apertures 5' and 6' respectively. Each of the apertures is defined by two straight wall sections 21 which intersect the di-rection of relative displacemen~, indicated by the arc 10, at right angles, and by two further wall sections 22 which connect the ends of th0 wall sections 21 and extend in the direction of displacement. In a rotary valve the direction of displacement a~ any point is tangent:ial, so that a wall section extending "in the direction of ~isplacement" constitutes a part-cylindrical surface and a wall section "intersecting the direction of displacement at right--angles" con-stitutes a radially extending planar surface. The aperture cross-section in valve plates for a rotary valve thus corresponds to a sector of an ~mnulus. In accordance with the invention, this aperture cross-section must occur in the region where ~he discharge aperture opens onto the sliding surface 4. As can be seen in Figure 5, the cross-section can retain the same shape over the whole thickn0ss of the pla~e or, alterna~ively ~.ay change towards the opposite side of the plate~ for example into a circular shape.
The advantages of the cross-sectional shape of the discharge aper-tures 5' and 6' according to the invention may be seen in Figures ~ and 5 by comparison with Figure 3. When pouring in the throttled position (Figure 5), only the straight working edges of the opposed radial wall sections 21 and the adjoining surface regions 25 of the sliding surfaces 4 (Figure 5) are exposed to the melt, whilst all other edge regions, i.e. approximately three-quarters of the periphery are always covered. The adjoining eroded regions 25 of the sliding surfaces 4 are ~herefore much smaller than the corresponding surfaces 26 in the case of the known round discharge openings (Figure 3). What is even more important is that in the closed position ~Figure ~) the solidiied "metal parts" or "tongues" formed in the region 25 have such a shape that when the valve is next opened they do not jam between ~he plates but are easily pushed out into the flow channel without causing damage. For the purpose o proper comparison of the surface regions 25 and 26, Figures 3 and 4 are based on aper-ture cross-sections of the same size si~uated on the same mean radius wi~h the same minimum distance of overlap. Figure 5 also shows ~ha~, wh0n pouring is completed, the extent of the wear along the working edg0s and the adjacent sur-face regions can be very easily observed from the outside ~in an in~ermedia~e position of the apertures roughly as shown in Figure 5), which is not so 0asy with round apertures.
Figure 6 shows the preferred geometrical relationship of the various walls of the aperturc cross-section. A balanced ratio bctween ~he width ~in the radial dire~tion) and length (in the direction of displacement) of th0 aper ture cross-section 5', or 6', is produced when all the wall sections touch an 7~36 imaginary inscribed circle 2~, as shown in Figure 6. It is~ however~ also pos-sible to deviate from this rule of "inscribed circle contact," in the choice of the aperture length, ~hus, for example, the apertures of the base plate and the sliding plate can have a greater bu~ equal length or the sliding plate can have several apertures with differing lengths; advantageously, however the width of the co-operating apertures in the base plate and the sliding plate are always chosen the same and naturally on the same radius so that the edges of the wall sections 22 are never directly exposed to the melt.
By way ~f comparison Figure 6 shows a circular cross-section ~ with the same area as thQt of *he aperture shaped in accordance with the invention.
It will be seen that the displacement path Sl between the open and closed po-sition for the plates according to the invention is shorter than the correspond-ing displacement path S for plates with apertures of circular cross-section.
In addition the radial width of the area 5' according to the invention is small-er than that of the area 5 of the same cross-sectional area which maXes it pos-ible for the apertures in the plates of the present invention to be positioned so as to have a greater mean radius.
Figures 7 to 9 show embodiments of valve plates for a linear sliding gate valve in accordance with the invention. Figure 7 shows a pair of valve plates 11, 12 in the closed position and having a discharge aperture 15' or 16', respectively arranged on the central axis which extends parallel to the direction of displacement 13~ Each of the discharge-~'apertures is defined by two wall sec-tions 31 intersecting the direction of displacemen~ at right angles and two further wall sections 32 which extend in the direction of displac~ment and con-nect the two ends of the wall sections 31. In t'he preferred embodiment shown in Figure 7 the aperture cross-section is a square, i.e. all the wall sections contact an imaginary inscribed circle and the length o-f the aperture is equal to its width.
t7~3~
All the statements made above in connection with ~igures 3 to 6 in relation to the proportions in the rotary gate valve, and in particular the op-eration of the construction shown in ~igures 4 and 5 in comparison with valve plates with circular discharge apertures, also apply by analogy to valve plates ~or a linear sliding gate valve. This results from the ~act that a rotary move-ment with an inEinitely large notional rotational radius is in fact a linear movement.
Figure 8 shows a modi~ied construction in which the wall sections 33 intersect the direc~ion o~ displacement not at right angles but at an obtuse angle, although still at the same angle. In the case of a linear gate valve the wall sections 32 and 33 then form an obtuse angled parallelogram ~rhombus and rhomboid). This construc~ion is also applicable by analogy to the discharge apertures in valve plates for a rotary sliding gate valve.
Finally, Figure 9 shows a construction in which the wall sections 31 are conn0cted by two longer wall sections 34 extending in the direction of displacement. The rectangular cross-section thus formed corresponds to the con-struction in which the apertures constitute a sector of an annulus with a great-er length relative to the construction in which the walls contact an inscribed circle, as already described in connection with the rotary sliding gate valve.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a sliding closure unit for regulating a stream of molten metal discharged from a metallurgical vessel and including an upstream stationary plate adapted to be mounted in fixed relationship with respect to the metallurgical vessel and having therethrough a flow-through opening, and a downstream sliding plate in abutting contact with said stationary plate and having therethrough at least one flow-through opening to be selectively moved into and out of alignment with said flow-through opening of said stationary plate upon movement of said sliding plate in a direction of movement with respect to said stationary plate, said stationary and sliding plates consisting of refractory material and having abutting relative sliding surfaces subject to erosion adjacent to said flow-through openings by said stream of molten metal, the improvement comprising:
means for reducing erosion damage to edges of said flow-through openings, at least in the areas thereof opening into said sliding surfaces, said means comprising a construction such that each said flow-through opening is defined, at least in the area thereof that opens onto the respective said sliding surface, by two planar wall surfaces which extend at equal angles across said direction of movement and by two other wall surfaces which are connected to ends of said planar wall surfaces and extend in directions parallel to said direction of movement.
means for reducing erosion damage to edges of said flow-through openings, at least in the areas thereof opening into said sliding surfaces, said means comprising a construction such that each said flow-through opening is defined, at least in the area thereof that opens onto the respective said sliding surface, by two planar wall surfaces which extend at equal angles across said direction of movement and by two other wall surfaces which are connected to ends of said planar wall surfaces and extend in directions parallel to said direction of movement.
2. The improvement claimed in claim 1, wherein said two planar wall surfaces extend at right angles with respect to said direction of movement.
3. The improvement claimed in claim 1, wherein said two planar wall surfaces extend at angles other than right angles with respect to said direction of movement.
4. The improvement claimed in claim 1, wherein said two planar wall surfaces and said two other wall surfaces are positioned to extend tangentially to an imaginary circle within said area opening into said respective sliding surface.
5. The improvement claimed in claim 1, wherein said two other wall surfaces are positioned to extend tangentially to an imaginary circle within said area opening into said respective sliding surface, and said two planar wall surfaces are positioned to be outwardly spaced from said imaginary circle.
6. The improvement claimed in any one of claims 1, 2 and 3, wherein the cross-sectional shape of at least one said opening defined by said surfaces is the same throughout the entire plate thickness.
7. The improvement claimed in any one of claims 1, 2 and 3, wherein the cross-sectional shape of at least one said opening is altered at different positions through the plate thickness, such that the shape of said opening at said area opening into said respective sliding surface is different than the shape of said opening at the opposite plate surface.
8. The improvement claimed in any one of claims 1, 2 and 3, wherein said sliding closure unit comprises a rotary sliding closure unit, said sliding plate rotates about an axis in said direction of movement, and said two other wall surfaces are curved surfaces.
9. The improvement claimed in any one of claims 1, 2 and 3, wherein said sliding closure unit comprises a linear sliding closure unit, said sliding plate moves in a straight direction of movement, and said two other wall surfaces are planar surfaces.
10. The improvement claimed in any one of claims 1, 2 and 3, wherein, when said openings in said plates are in alignment, said two other wall surfaces of said sliding plate are aligned with said two other wall surfaces of said stationary plate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH7138/80A CH649610A5 (en) | 1980-09-24 | 1980-09-24 | LOCKING PLATE PAIR FOR A SLIDING LOCK. |
| CH7138/80-3 | 1980-09-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1187696A true CA1187696A (en) | 1985-05-28 |
Family
ID=4320552
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000386469A Expired CA1187696A (en) | 1980-09-24 | 1981-09-23 | Valve plates for a sliding gate valve |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5781951A (en) |
| BE (1) | BE890313A (en) |
| BR (1) | BR8106004A (en) |
| CA (1) | CA1187696A (en) |
| CH (1) | CH649610A5 (en) |
| DE (1) | DE3131819A1 (en) |
| ES (1) | ES267850Y (en) |
| FR (1) | FR2490767A1 (en) |
| GB (1) | GB2085126B (en) |
| IT (1) | IT1142825B (en) |
| ZA (1) | ZA816655B (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT381571B (en) * | 1982-11-15 | 1986-11-10 | Oemv Ag | DEVICE FOR STAGE PRESSURE RELEASE WHEN RELAXING, IN PARTICULAR, HOT GASES |
| DE3326797A1 (en) * | 1983-07-26 | 1985-02-07 | Silo Verfahrens AG, Zug | SLIDE DEVICE |
| CH663365A5 (en) * | 1984-05-11 | 1987-12-15 | Stopinc Ag | SEALING PLATE COUPLING FOR A SLIDING CLOSURE ON THE SPOUT OF MELT, IN PARTICULAR METAL MELT, CONTAINERS CONTAINING. |
| CH663368A5 (en) * | 1984-06-20 | 1987-12-15 | Stopinc Ag | SLIDING SEAL FOR THE SPOUT, IN PARTICULAR HORIZONTAL SPOUT, MILLED FROM METAL MELT. |
| DE3432613C1 (en) * | 1984-09-05 | 1985-05-02 | Didier-Werke Ag, 6200 Wiesbaden | Fireproof plate for slide closures on metallurgical vessels |
| AU591889B2 (en) * | 1985-03-26 | 1989-12-21 | British Steel Plc | Improvements in or relating to outlet valves for metal containing vessels |
| DE3545764A1 (en) * | 1985-12-21 | 1987-06-25 | Didier Werke Ag | PLATE UNIT FOR SLIDE LATCHES |
| ATE72528T1 (en) * | 1988-06-09 | 1992-02-15 | Hepworth Refractories Belgium | METHOD OF CONTROLLING THE FLOW RATE AT A VALVE AND VALVE FOR CARRYING OUT THIS PROCESS. |
| GB2249978B (en) * | 1990-11-26 | 1994-08-24 | Ishikawajima Harima Heavy Ind | Tundish flow control |
| CN104249210A (en) * | 2013-06-28 | 2014-12-31 | 鸿富锦精密工业（深圳）有限公司 | Multi-point welding jig |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB266842A (en) * | 1925-12-15 | 1927-03-10 | George Alfred Hammond | Improvements in or connected with dampers |
| GB485519A (en) * | 1937-09-25 | 1938-05-20 | Peter Marinus Kristensen | Improvements in and relating to outlet valves for sinks and the like |
| US2470488A (en) * | 1943-08-16 | 1949-05-17 | Anemostat Corp America | Air flow control means |
| US2651320A (en) * | 1949-03-31 | 1953-09-08 | Atlantic Refining Co | Gate valve |
| US3448761A (en) * | 1966-01-12 | 1969-06-10 | United States Steel Corp | Valve for regulating flow of high-temperature liquids |
| NL162579B (en) * | 1969-02-22 | Didier Werke Ag | DEVICE FOR REGULATING AND CLOSING THE DISCHARGE OF MOLTEN METAL THROUGH A BOTTOM OPENING FROM A RESERVOIR. | |
| JPS5135948U (en) * | 1974-09-10 | 1976-03-17 | ||
| FR2403134A1 (en) * | 1977-07-04 | 1979-04-13 | Detalle Pol | Bottom pour sliding stopper for metallurgical vessels - contains two plates sliding towards each other to close outlet hole |
| DE7722822U1 (en) * | 1977-07-21 | 1977-10-20 | Deutsche Ranco Gmbh, 6832 Hockenheim | Valve for the water circuit of a vehicle |
| DE2834643A1 (en) * | 1978-08-08 | 1980-02-28 | Detalle | Bottom pour sliding stopper for metallurgical vessels - contains two plates sliding towards each other to close outlet hole |
-
1980
- 1980-09-24 CH CH7138/80A patent/CH649610A5/en not_active IP Right Cessation
-
1981
- 1981-08-12 DE DE19813131819 patent/DE3131819A1/en not_active Ceased
- 1981-09-11 BE BE0/205932A patent/BE890313A/en not_active IP Right Cessation
- 1981-09-18 IT IT49327/81A patent/IT1142825B/en active
- 1981-09-21 BR BR8106004A patent/BR8106004A/en unknown
- 1981-09-22 GB GB8128596A patent/GB2085126B/en not_active Expired
- 1981-09-22 JP JP56148935A patent/JPS5781951A/en active Pending
- 1981-09-22 FR FR8117842A patent/FR2490767A1/en active Granted
- 1981-09-23 ES ES1981267850U patent/ES267850Y/en not_active Expired
- 1981-09-23 CA CA000386469A patent/CA1187696A/en not_active Expired
- 1981-09-24 ZA ZA816655A patent/ZA816655B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| IT1142825B (en) | 1986-10-15 |
| FR2490767A1 (en) | 1982-03-26 |
| BE890313A (en) | 1982-01-04 |
| CH649610A5 (en) | 1985-05-31 |
| GB2085126B (en) | 1985-02-27 |
| FR2490767B1 (en) | 1984-12-28 |
| ES267850Y (en) | 1983-11-16 |
| DE3131819A1 (en) | 1982-04-22 |
| BR8106004A (en) | 1982-06-08 |
| IT8149327A0 (en) | 1981-09-18 |
| GB2085126A (en) | 1982-04-21 |
| ES267850U (en) | 1983-05-01 |
| ZA816655B (en) | 1982-09-29 |
| JPS5781951A (en) | 1982-05-22 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |