DD210224A5 - METHOD FOR PRODUCING A SEAL ASSEMBLY ON A SLIDING SHUTTER - Google Patents

Abstract

At a sliding closure for metal, in particular light metal melts, the tightness along the sliding surfaces of the closure bodies is to be ensured during a large number of slide movements, thereby allowing extended periods of operation without changing the closure bodies. This is achieved by a sealing arrangement produced by continued closure operation in the presence of melt and when using an abriebfaehige closure body, which is in sliding contact with an abrasion-resistant closure body. A mixture of abrasion and metal particles formed in the process builds up between the closure bodies in wear grooves, which form in the abradable sliding surface. Application for linear as well as rotary and pivot locks and equally for level or z. B. cylindrical, conical or spherical Gleitflaechen.

Description

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3erlin, the 14th 12, 83 AF F 16 D / 254 130 1 62 639 27

Method for producing a seal arrangement on a slide eve rs chi u S

Field of application of the invention

The invention relates to a method for producing a seal arrangement on the sliding one another _t preferably plate-shaped closure bodies of a Schisbeverschlüsses for casting of metal, in particular light metal melts,

Characteristic of the known technical solutions

In sliding closures, as they are primarily used for casting steel, the tightness u .. a »guaranteed by accurate plan grinding both closure body (fixed and movable closure plate), As known _t causes the flowing molten steel despite the use of very high-quality Feuerfestvverkstorfe an intensive wear Both at the plate holes (flow openings) , as well as at the sealing surfaces, which is why the plates must be replaced after a few casts for safety reasons »

From DE-AS 2 404 881 a sealing arrangement on a rotary slide closure is known which consists of an annular , concentric with the axis of rotation sealing ring; the latter can be arranged on the circumference of the plates or inserted between the plates in a groove extending from the sealing surfaces. This arrangement is intended to prevent the escape of melt

QQQiIi

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between the plate sealing surfaces prevent against the circumference outward d '. It is intended as a safeguard against breakthrough in the event of a serious malfunction or damage. At the mentioned signs of wear bzvi. the limited use of the. However, this arrangement can not change plates.

In contrast, a proposal according to DE-OS 3 031 377 aims in this direction.

Thereafter, the penetration of melt between the plate sliding surface is to be prevented and the solidification of molten metal to be counteracted. Oies done according to the local proposal _{z by} that VerschschluSplatten be made of certain different materials together, namely, a fixed plate made of soft! * Lubricating and poorly wettable material of high thermal conductivity with a movable plate of hard and dense material low thermal conductivity » On the other hand However, it has been shown that even with low wetting there is always a certain adhesion between the plate material and the melt and, when the closure is actuated, a "pull-in" of small amounts of melt between the plate slides is unavoidable. Furthermore, a high thermal conductivity of the stationary plate is indeed a suitable means (in conjunction with other measures) to prevent solidification of the melt in the region of the flow opening or to ensure spontaneous flow when the closure is opened. However, at some distance from said opening the temperature on the plate sliding surface necessarily be lower than the solidification temperature of

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Melt, otherwise the tightness of the closure is in question.

Object of the invention

The aim of the invention is to provide a more functional and economically usable sealing arrangement on a sliding closure using two high utility properties having closure body for producing the seal assembly.

Presentation of the essence the invention

The object to be achieved by the invention is to provide a method for producing a seal assembly on a sliding shutter / which ensures the tightness along the Glaitflächen on the SchiebeverschiuS during a large number of slide movements and thereby extended Setriebsperioden ohne.Wechsel the closure body are made possible In this context, it should be mentioned that under certain operating conditions, especially when casting light metal melts, the wear on the flow openings of the closure plates is low; In such cases, practically the condition of the sliding sealing surfaces is decisive for the duration of use of the plates.

According to the invention the Aufgaoe is achieved in that by continuing relative displacement between a at least on its sliding surface abriebfähigen closure body and a standing in sliding contact with this abrasion-resistant closure

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-A-

body with simultaneous impingement of the closure body with melt, forming a mixture of abrasion and metal particles between the VerscnluSkörpern, the mixture is stored in substantially groove-shaped and extending in the direction of wear, formed by wear, depressions in the sliding surface of the abrasive VerschlußSkörper

In a further embodiment of the invention it is provided that a fixed abri-ebf ähiger closure body and a sliding abrasion-resistant closure body can be used.

The invention is further distinguished by the fact that substantially linear depressions or closure elements of a rotary slide closure essentially circular or arcuate depressions are formed on closure bodies of a linear disk closure.

In the context of the invention is also that predominantly consisting of graphite or predominantly made of boron nitride with hexagonal lattice structure abriebfähige closure body are used as abrasion-resistant closure body are particularly suitable from high-toned materials ₃ but also closure body have proven to be advantageous, the predominantly consist of zirconium oxide or predominantly of aluminum titanate.

By doing the invention. Only a few thousand more, because "more than 10 000 spool actuations with the same shutter bodies ensure a tight seal, the

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Finally opened up new fields of application. So z. B, a continuous operation of melting, holding or pouring furnaces under standing melt possible or the use for continued pouring of separate, measured quantities of melt in the molding.

In connection with the invention is to be remembered that the seal along the sliding surfaces of the closure body, starting from the fixed flow opening> all sides against the edge of the sliding surface and - in the closed position dss movable closure body - against the flow opening, ie in In view of the requirement mentioned second above, it is certainly surprising that according to the invention recesses or "grooves" formed by wear are included in the sealing arrangement. Targeted use of abrasion and wear also completely contradicts the conventional notion of "lubrication", which is aimed precisely at preventing wear and reducing friction (this, of course, does not exclude that the abradable material may also have favorable sliding properties affect aer gesaraten sliding surface as low friction),

As decisive for a continuous tightness with continued operation of the closure according to the invention the occurrence of abrasion has been recognized in mixture with metal particles. Although it is not possible to generalize and conclude

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Bend indicate which concrete material pairings lead to the goal, but this can be - determined by the invention - from case to case with relatively simple experiments *

One can imagine the operation of said batch ira essential so that the presence of the abrasive particles prevents the formation of contiguous metal bodies between the sliding surfaces, which would have to lead to rapid destruction of the closure body in solidification as "metal tongues" or "sieves". It was found that the mixture has a very low strength, but that still a gewisser'Zusammenhalt between the particles consists f producing a "washout" is prevented and the groove-shaped recesses remain permanently filled by Gera Enge. Incidentally, the sealing effect obviously does not depend on whether the metal particles in the mixture remain molten or (temporarily) solidify; even if, after a series of operations z. B ₅ the Scbraelzegefäß is emptied and the temperature at the closure sliding surfaces drops considerably below the solidification temperature of the melt, later, after re-filling of melt ^ the closure can be operated properly again.

The invention is equally applicable to linear sliding closures, such as rotary and Scnvenkverschlüssen; The rotational movement can be of alternating direction (analogous to the linear shutter) or always ira same sense. The attachment of the closure to the furnace or SchmelzegefäS can also be done with horizontal, inclined or vertical position of the sliding surfaces.

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Working Example

The invention will be explained in more detail below by exemplary embodiments. In the accompanying drawing show:

FIG. 1 shows essential parts of a linear sliding closure attached to a melt vessel in longitudinal section; FIG.

Fig. 2i dia view of the sliding surface of the fixed closure plate (partially broken away) of the closure of Fig. Lj

Fig. 3: a corresponding view of the fixed closure plate of a rotary slide closure;

Figure 4 is a section along the line IV - IV in Figure, through a lot of the fixed and the movable shutter plate in high magnification.

Fig. 5: a microscopic cross-section image of the mixture of abrasion and metal particles in section along the line V-V in Fig, 3, d. h, perpendicular to the direction of movement (magnification ca * ISOfach linear), and

Fig. 6: a similar Schuffbildaufnahme in section along the line VI-VI in Fig, 3 .. d ,. H. in the direction of movement (magnification approx. 150 times linear) *

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In the embodiment of FIG * 1, only the two closure body - here in the form of two flat plates 12 and 14 - drawn with solid lines _ä further parts of the slide closure IO and parts of the melt vessel 1 »to which the sliding shutter 10 is grown, indicated only by dash-dotted lines , The melting vessel 1 contains a molten metal 3 _{ for example, an aluminum bronze, and has a spout opening 2, which leads to the sliding closure 10. The stationary plate 12 of the closure is formed by a 3odenplatte * which is held in a fixed to the melt vessel 1 base plate 16 and a the pouring spout 2 continuing flow opening 13. With the bottom plate or, with the sliding surface 9, the movable designed as a slide plate plate 14 of the shutter is ira sliding contact, d. H". _f the slide plate is, together with the · receiving spool 13 in the direction of arrow P entlang__der_ GlejLtf laugh 9 to and fro. The flow opening 15 of the slide plate is brought in a known manner either with the flow opening 13 of the sod plate to cover ('open position of the closure) or, as shown, offset against this (closed position), to the flow opening 15 can in a known manner in the slider 13th connect inserted spout sleeve 17.

It is needless to another structure of the shutter according to Fig * 1 ira each represent _t 'as this is not necessary for the understanding of the invention. Only for the sake of completeness is Swiss Patent Application 3255 / 81-5 or, the Federal Republic of Germany patent application P 3 208 101.4, the CH-PS 523 730 and the DE-PS 1 951 447 examples of linear

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It should, however, be emphasized that the seal assembly according to the invention is not limited to plate-shaped closure bodies with a flat sliding surface, such as, for example, sliding door closures and European Published Patent Application 0 040 692 or DE-OS 3 013 975. 8, according to Fig » I ₁ realized v / earth, but in principle also on closure bodies of different shape with z« 3, cylindrical , conical or spherical sealing surface »

The tightness of the sliding closure 10 during its commissioning is given in a known manner characterized in that the sliding surfaces of both plates 12; 14 are exactly flat and the plates 12; 14 to ensure the tightness not only for a few operations, but in the sense of the invention even with continued operation with thousands of operations, is the one closure body, in the present case, the fixed bottom plate at least along its sliding surface 9 made of an abradable material, while the other closure body, here the displaceable plate 14, made of abrasion-resistant material. The abradability of the material shows signs of wear on the sliding surface 9 of the plate 12, which are shown in more detail in Figs. 2 and 4 and are explained below:

"Venn the shutter with new plates 12; 14 and under Seaufschlagung with molten metal 3 as shown in FIG. 1 continues actuated, d, h. the slide plate opposite the sod plate

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is shifted back and forth in the direction of arrow P, is soon on the sliding surface 9 of the abradable plate 12. A "wear pattern" , as can be seen from Fig. 2. In a surface area which extends from the flow opening 13 by approximately the stroke length on both sides (the flow opening 15 in the closed position is indicated in FIG. 2), more or less randomly arranged and shaped groove-shaped depressions 19 are formed essentially in the sliding direction ". The width of the area mentioned corresponds approximately to the diameter of the flow opening 13 (even if this is 3, larger than that of the flow opening 15) _t it can also go beyond this diameter as shown in FIG 2, the Fig. 4 shows in high magnification This typical wear pattern in cross-section, As can be seen, the mentioned recesses 19 or "wear grooves" are not empty, but from the beginning filled with a mixture of material 20 _f which arises in the shutter actuation between the plates 12 and 14 and in the Depressions 19 are lodged "It is a mixture of abrasive particles A of the abradable plate 12 and small metal particles M or droplets of the molten metal 3 which, during the sliding movement, move between the plates 12; As can be seen from FIG. 4, as expected, the sliding surface of the abrasion-resistant plate 14 remains practically flat or without wear.

The phenomena and operations described above result in the closure being operable and reliably sealed during a very large number of operations

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remains. Thus, at the beginning of operation, a sealing arrangement is produced between the closure bodies by actuation of the closure under the action of melt in the manner described. It has been shown that the wear or the depth of the wear grooves does not increase steadily, but perhaps remains practically constant after a few hundred actuations. The observed groove depth ranges from a few tenths of an inch to about a millimeter *

Even with the reverse arrangement of the closure body - abrasion-resistant body fixed and abriebfähiger body displaceable - the production of the described seal assembly in the same way is basically possible »This, however, in certain respects have certain disadvantages _T z .. B. because then the abriebfähige sliding surface permanently with the standing molten metal 3 is in contact.

It stands out. that the described "wear pattern" with incorporated mixture of material on the abradable sliding surface is mentioned only in FIG. 2 surface area, but not in the surrounding areas of the sliding surface 9, This means (as the composition of the batch 20 shows) that the process is bound to the presence of melt. It can be assumed that in the relative displacement of the closure body low Schraelzemengen be drawn between the sliding surfaces and then, possibly after their solidification, cause abrasion; the phenomenon was also observed with such materials, which in themselves are derived from the melt

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be only slightly moistened (eg. B "different types of graphite) Although the operations in the interior of the recesses 19 of the direct observation is not accessible _t is believed that the local composition of the mixture 20 is constantly changed with continued operation of the shutter" have, however, The particles of this batch 20, at least in the cooled state, a certain cohesion on * "If the shutter stopped after prolonged operation and the shutter plates are then taken apart, the mixture 20 preferably adheres to the surface of the wear-resistant plate 14 easily adhere.

Of course, it is not necessary that the one closure body is made of abrasion-resistant material, but it is sufficient if this property is given at least on its sliding surface. The closure body or the sod plate can be two or more in thickness Layers composed of different materials. In this way, it is possible to produce closure bodies which, in addition to the required abradability on the sliding surface, have certain advantageous correspondences of material properties, for example with regard to thermal conductivity, flexural strength, hardness, and sw.

FIG. 3 shows, in contrast to FIG. 2, the view of the wearable sliding surface of a stationary plate 22 of a rotary slide closure with its eccentrically arranged flow opening 23, whereby the position of the flow opening 25 of the (not shown)

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Asked) movable, abrasion-resistant closure plate in the closed position is indicated by dash-dotted lines. Upon continued actuation of said shutter by rotating the movable closure plate in the direction of arrow R that of Figure "apparent 3" VerschleiSbild "produced, d» is h, there are formed substantially circular, concentric rillenförinige recesses 19 'in aer abradable sliding surface of the plate 22 On the other hand, if the rotary shutter were to be opened and closed by partial rotations with changing directions of rotation, as is also known, the recesses 19 'would extend only over a corresponding circular arc of limited length. Moreover, the above statements on FIGS. 1, 2 and 4 apply analogously to the production and properties of the sealing arrangement and in particular the material mixture stored in the wear grooves also for the exemplary embodiment according to FIG.

The microscopic Schuffbilder of Fig., 5 and 6 give an idea of the structure of the constituent of the seal assembly forming batch 20 (Fig. 4). After the seal assembly was made in the manner described and the shutter was in operation for a long time on a rotary closure according to the Seispiel of Fig. 3 oer closure was shut down and dismantled. 3eim separating the rotatable fixed by aer closure plate remained most of the in the recesses 19 'embedded batch 20 on the sliding surface 14' of the rotatable plate adhere. This sliding surface 14 'of the rotatable plate forms the lower shown in Figs. 5 and 5

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Edge. The sliding surface 14 'with the mixture 20 was then covered with a hardening casting resin G (FIGS. 5 and 5), and after curing thereof the preparation was cut along a line VV on the one hand and along a line VI - VI in FIG. ie once transverse to the direction of movement and in the other 'case tangential to a certain wear groove, d, h'. at the relevant point of contact of the cutting line in the direction of the operation. At the relevant points, the shield images Fig. 5 and Fig. 6 were then recorded. In both pictures the embedded metal particles M are recognizable as bright _{ practically white spots. The abrasion particles A mixed with the metal particles M appear gray. The more or less large dark to black spots H, on the other hand, are interpreted as cavities in the mixture or as unevenness in the Schilffebene which arose during the production of the preparation.

The Fig * 6 can be compared to Fig. 5 clearly recognize the direction of movement in the closure operation. Both figures show a rather irregular mixture, but it is considered essential that no larger "lumps" form, but that the metal particles are interrupted again and again by interposed Abriebteilchen. Hereinafter, some concrete closure material or material pairings, as used successfully in the manufacture of the described sealing arrangement, are given as examples. It is understood that this information can not be exhaustive. "The choice must be made between materials that are

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The decisive criterion for the suitability is then "whether the described abrasion phenomena and the mixture can be achieved in the case of selection experiments in the presence of melt, which then leads to the ' Production of the Sealing Arrangement and thus the Reliable Continuous Operation of the Verschluß ses Confirms "Previous findings and tests confirm that as abriebfähige materials especially graphite or mixtures sit high graphite content or other materials with similar, characteristic" platelet "structure is suitable

Example i:

A closure plate made of graphite (99 % graphite content 18 VoI, - ^ open porosity) was as Abriebfähige. fixed plate in conjunction with an abrasion-resistant slide plate zirconia (95 % ZrO) used in a linear sliding closure attached to a runner. By continued actuation of the closure, measured amounts of an aluminum casting alloy (G-AlSiQMg according to DIN 1725, with 9 % Si and 0 ₄ 3 % Mg) were cast at a temperature of about 750 ° C. In this case, the seal assembly was prepared in the manner described. After about 3000 actuation strokes without interference and with perfect tightness of the closure of the casting operation was discontinued, and the shutter plates were removed to examine the seal arrangement. It showed that the plates could have been used without risk »

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Example 2:

A rotary shutter was equipped with an abradable, fixed closure plate of hot-pressed 3N boron nitride with hexagonal lattice structure and a rotatable plate of ZrO (same material as Example 1). In a test facility, a Rsinaluminium melt (99.5 % Al) of 750 ⁰ C. due to continuous "opening and closing of the closure poured off" After 965 trouble-free actuations (revolutions) in the course of which the described sealing arrangement had been produced, the experiment was aborted.

Example 3:

The same closure as in Example 2 was subjected to a continuous test in the same experimental equipment and with the same melt / but with a different panel assembly. In this case, a fixed sheet of high graphite carbon (over 92 % electrographite) with an abrasion resistant rotatable panel was formed high grade alumina material (90 % Al_O ^., S % SiO ₀ ). The series of tests included no less than 10550 operations, - d. h * Castings with shorter or longer breaks and consequent cooling of the closure plates. Subsequent investigation revealed that the plates or seal assembly would have been still functional;

Example 4:

A rotary slide fastener was used as a tapping closure on a fused and Warrahalteofen for Rsinaluminium (about 750 ⁰ C)

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grown. The closure was equipped with a fixed plate of ectographite (99 % graphite , 14 VoI, -% open porosity) and a rotating plate of aluminum titanate Al ₇ TiO ₁ - and the operation was characterized by frequent tapping of relatively small amounts of melt. Thus, during approximately three and a half days, around 300 closure operations were achieved with complete leak-tightness. The subsequent investigation revealed that the plates or their seal arrangement were still suitable for operation. With closure plates made of the same materials, in a rotary slide closure attached to a test device, even approximately 6400 operations were performed without interference reached.

Claims (5)

62 639 27 - 18 Claim for invention 1. A method for producing a sealing arrangement to the slide on one another, preferably plate-shaped closing bodies of a sliding closure for the casting of metal, in particular light metal melts _s characterized in that by continued Rsiatiwerschiebung between an at least at its sliding surface (9) abradable seal body and a therewith in sliding contact standing abrasion-resistant closure body with simultaneous loading of the closure body with melt (3), to form a mixture (20) of abrasion (A) and metal particles (M) between the closure bodies, the mixture is in a substantially groove-shaped and in the direction of displacement (P; ) _{J: incorporated} by wear recesses (19, 19 ') in the sliding surface (9) of the abradable closure body, 2 * A method of manufacturing a seal assembly according to item I _t characterized in that a fixed abriebfähigsr closure body and a sliding abrasion-resistant closure body (14) are used, 3, a method for producing a seal arrangement according to item 1 or 2 on closure bodies of a linear sliding closure, characterized in that in Vyesen Tlichen rectilinear depressions (19) are formed, 4 »Method for producing a seal arrangement according to item 1 or 2 on lock heads of a rotary screw Conclusion, characterized in that substantially
circular or circular recesses (19 ') are formed, 5. A process for producing a seal assembly according to item 1 to 4, characterized in that a predominantly consisting of graphite, abriebfähiger closure body is used. 6. A method for producing a seal assembly according to item 1 to A _1, characterized in that a predominantly consisting of 3ornitrid with hexagonal lattice structure, abriebfähiger VerschlußSkörper is used. 7. A method for producing a seal assembly according to item 1 to 4, characterized in that a high alumina, abrasion resistant closure body is used. S. A process for producing a seal assembly according to item 1 to 4, characterized in that a predominantly made of zirconia abrasion-resistant closure body is used. 9. A method for producing a seal arrangement according to item 1 to 4 ,. characterized in that a predominantly made of Alurainiuratitanat existing, abrasion-resistant closure body is used. - For this 2-page drawings -