US3109682A

US3109682A - Bearings exposed to heat

Info

Publication number: US3109682A
Application number: US133641A
Authority: US
Inventors: Plumat Emile
Original assignee: Glaverbel Belgium SA
Current assignee: AGC Glass Europe SA
Priority date: 1960-09-06
Filing date: 1961-08-24
Publication date: 1963-11-05
Anticipated expiration: 1980-11-05

Description

Nov. 5, 1963 E. PLUMAT BEARINGS EXPOSED TO HEAT Filed Aug. 24. 1961 PRESSURE Lvvzlvran EMILE PL uMAf cw MM A TTORA/ Y5 United States Patent 3,109,682 BEARINGS EXPOSED TO HEAT Emile Plumat, Gilly, Belgium, assignor to SA. Glaverbe], Brussels, Belgium, 21 Belgian company Filed Aug. 24, 1961, Ser. No. 133,641 Claims priority, application Belgium Sept. 6, 1960 12 Claims. (Cl. 30836.3)

The invention relates to bearings which are exposed to the action of heat and which are suitable, in particular, for a rotary shaft extending horizontally or in accordance with an inclined axis into a receptacle containing a molten substance, such as glass or a metal substance. Depending on circumstances, the said shaft may carry for ex ample a stirring means the purpose of which it is to stir the molten material with a view to mixing the upper and lower layers thereof, or a propelling means causing the molten substance to advance in a predetermined direction.

The horizontal or slightly inclined arrangement of the rotary shaft and of the bearings has the advantage that these members contact only the molten substance on the furnace side. Consequently, the choice of materials suitable for these members is restricted only by considerations in respect of their resistance to deterioration caused by the molten substance and it is unnecessary simultaneously to take into consideration their resistance to the furnace atmosphere which is extremely corrosive at the temperature obtaining in the furnace, as is the case when the shaft is so inclined that the bearings are located above the level of the molten substance. The horizontal or slightly inclined arrangement of the shaft does, however, involve certain problems in respect of fluid-tightness of the bearings. It is obvious that the molten substance must not be able to penetrate into the interior of the bearings since if it did so there would be a risk that it might jam the shaft as it solidified and it is not to be expected that smooth bearings could satisfy this requirement. It is one of the objects of the invention to provide bearings which will be fluid-tight relatively to the molten substance; other objects will be apparent from the description.

According to the invention, the bearings are incorporated in the wall of the receptacle, substantially between the vertical planes of the Wall faces, and comprise a cavity intended to receive a means preventing the molten substance from penetrating into the bearings, the said cavity being formed in a cylindrical member, between an inner end member and an outer end member, each of which are formed with an aperture bored to the diameter of the shaft which passes through them.

The cylindrical member and the inner end member are advantageously moulded together from a refractory metal material which is inert relatively to the molten material contained in the receptacle. The outer end member is preferably fitted on the cylindrical member and secured for example by screwing, and the assembly is sealed in the wall with the aid of a refractory mortar. The cylindrical member and its bottom plate may be of molybdenum, or of tungsten, or of a refractory alloy of these metals, or alternatively it may be of an agglomerated metal. Where required, they are covered with a protective layer preventing rapid wear by oxidation, for example a layer of a noble metal, or a layer of oxides, of nitrides, borides, or mixtures of these compounds.

The bearings are formed with an oblique conduit connecting the cavity with the exterior and permitting the introduction therein of a substance melting at a temperature below that obtaining in the receptacle. This material prevents the molten substance in the receptacle from penetrating into the interior of the bearings and it serves simultaneously as a lubricant. Although it is possible to use, for this purpose, a molten metal having 3,109,682 Patented Nov'. 5, 1963 a low melting point, use will preferably be made of a molten glass, due to the better lubricating properties of the latter. Advantageously, an extremely fusible glass is selected, so that it becomes unnecessary to maintain the bearings at an excessively high temperature, and this glass may be one selected from the diagram or from the SiO -PbOCaO-Na O diagram and the liquefaction temperature of which is of the order of 500 C. or even less. This substance is maintained in the cavity under excess pressure produced by some known, appropriate means and sufficient to lubricate the portions of the bearings constituting the bearing surfaces exposed to friction, and to prevent the entry of molten substances into the receptacle.

In order to prevent, on the outer side of the bearings, the congealing of the substance introduced into the cavity, this side may be reheated by an appropriate means, for example by electric resistance heating, but preferably it will simply be heat-insulated with the aid of a plate of refractory material applied against the wall and formed with an aperture through which the rotary shaft passes. The cavity may be provided with an inner packing device comprising a series of washers, made for example of only slightly fusible glass fibres, and pressed with the interposition of a bracing sleeve either against the inner end member or against the outer end member, or simultaneously against such two members, by screwing the top plate fast. The said only slightly fusible glass fibres may comprise fibres of a special glass, for example a glass which is rich in silica or consists of a mixture of silica and alumina.

In the accompanying drawings, a number of embodiments of the invention are illustrated by way of example.

FIG. l is an axial section through bearings sealed in the wall of a receptacle containing a molten substance.

'FIG. 2 is a similar section through bearings of a similar kind, provided with an inner packing device.

The bearings I serve for the introduction of a rotary shaft 2 into a receptacle containing a molten substance 3, the said shaft extending through a wall 4 made of a refractory material. The molten substance is for example glass contained in a tank furnace or coming from a furnace of this kind and flowing towards the point at which it is tapped, or it may be a molten metal. The shaft 2 carries an implement such as a stirrer for mixing the various layers of the substance 3 or a propelling means for displacing the latter in a desired direction.

The bearings are incorporated in the wall 4 and do not substantially project out of the vertical planes of the faces thereof. The said bearings comprise a cavity 5 which may communicate with the exterior through a conduit 6 and they consist of a cylindrical member 7, preferably moulded together with the inner end member 8, and an outer end member 9 secured on the member 7 by screwing. The member 8 and 9 are each formed with an aperture bored to the diameter of the shaft 2. The inner end member 8 and the cylindrical member 7, which are particularly exposed to the action of heat, are made of a refractory metal, for example of molybdenum, tungsten, or an agglomerated metal which is inert to the molten substance 3 and, where required, they are also protected against oxidation by a layer of noble metal or by a layer of oxides, nitrides, borides, or mixtures of these compounds, this also applying to the shaft 2.

The cavity 5 is filled with a molten substance such as extremely fusible glass, which remains liquid at a temperature below that of the molten substance 3', or with a metal having a low melting point, or alternatively with an alloy. This substance, introduced into the cavity through the conduit 6, is maintained under excess pressure which causes it to penetrate into the bores in the members 8 and 9 and -prevents the molten substance?! from entering the cavity furthermore, it reduces the friction between the shaft 2 and the bearing 1, thus serving as a lubricant. This excess pressure may be a hydrostatic pressure orone produced by some other known and appropriate means, In order to prevent excessive cooling taking place on the side of the outer, end member 9, a heat insulating means consisting of a plate of refractory material 10 is provided on the outer face of the Wall 4.

' In the embodiment according to FIG. 2, which may or may not be combined with that illustrated in FIG. 1, fluidtightness of the bearings is provided by means of an inner packing device comprising a series of washers 11 pressed by a bracing sleeve 12 against the members 8 and 9 or against only one of the said members. The Washers 11 are made from a material which resists heat, for example of only slightly fusible glass fibres. The washers 11 are pressed or jammed against the plates by screwing the member 9 into the cylindrical part 7.

Of course, the invention is not limited to the embodiments which have been described and illustrated by way of example and the scope of the invention would not be exceeded if modifications were to be made.

I claim:

1. In a receptacle for hot molten material and having a wall portion of substantial thickness, the inner surface of which is engaged by the molten material in the receptacle, said wall portion having an opening located below the normal level of the molten material in the receptacle and extending transversely entirely through such wall portion, a rotatable shaft extending through such opening and projecting beyond the inner and outer surfaces of said wall portion, a sleeve member lining the interior Wall of such opening and substantially spaced from the exterior surface of said shaft, an inner end member contained in such opening and closing the inner ends of the latter and said sleeve member, an outer end member contained in such opening and closing the outer ends of the latter and said sleeve member, said inner and I outer end members having apertures with diameters substantially the same as the shaft which passes through them, and together with said sleeve member defining a substantially closed, cavity enclosing said shaft within said opening, and means contained in said cavity and together with said sleeve member and said end members forming a liquid tight connection preventing the hot molten material in the receptacle passing through said wall portion to the exterior thereof, said shaft, sleeve member and inner end member being made of materials rendering them relatively inert to said hot molten material in the receptacle.

2. The combination defined in claim 1, in which said inner end member is integral with the inner end of said sleeve member, and the inner surface thereof is substantially fiush with and forms a continuation of the inner surface of said wall portion.

3. The combination defined in claim 1, in which the outer end of said sleeve member terminates short of the outer surface of said wall portion, and in which said outer end member is separable from said sleeve member and comprises an outer cap portion having a diameter substantially the same as the diameter of said opening and located in the outer end of said opening beyond the outer end of said sleeve member, and said' outer end member comprises a plug portion seated in and adjustably connected to the outer end of said sleeve member.

4. The combination defined in claim 1, in which the means contained in said cavity comprises hot molten material under pressure.

5. The combination defined in claim 4, in which the hot molten material is molten glass.

6. The combination defined in claim 4, including means connected with said outer end member for maintaining said molten material in the cavity in molten condition.

7. The combination defined in claim 6, in which said connected means comprises a plate of'refractory material applied against the outer surfaces of said outer end member and Wall portion and provided with an aperture through which said rotary shaft extends.

8. The combination defined in claim 4, in which an oblique conduitextends obliquely outwardly from said cavity, through said lining member, and said wall portion to the outer surface of the latter, and enables the introduction therethrough into said cavity of said hot molten material.

9. The combination defined in claim 3, in which the means contained in said cavity comprises compressible packing material enclosing'said shaft and pressed against at least one of said end plates through said adjustable outer end member.

10. The combination defined in claim 9, in which said packing material is constituted of glass fibre.

11. The combination defined in claim 9, in which the means contained in said cavity comprises a bracing sleeve lining said sleeve'member and cooperable with said outer end member to effect compression of said packing mate'- rial.

12. The combination defined in claim 11, in which said bracing sleeve is formed to define a space in said cavity, and hot molten material under pressure filling the space formed by said sleeve.

2,008,543 Dickinson July 16, 1935

Claims

1. IN A RECEPTACLE FOR HOT MOLTEN MATERIAL AND HAVING A WALL PORTION OF SUBSTANTIAL THICKNESS, THE INNER SURFACE OF WHICH IS ENGAGED BY THE MOLTEN MATERIAL IN THE RECEPTACLE, SAID WALL PORTION HAVING AN OPENING LOCATED BELOW THE NORMAL LEVEL OF THE MOLTEN MATERIAL IN THE RECEPTACLE AND EXTENDING TRANSVERSELY ENTIRELY THROUGH SUCH WALL PORTION, A ROTATABLE SHAFT EXTENDING THROUGH SUCH OPENING AND PROJECTING BEYOND THE INNER AND OUTER SURFACES OF SAID WALL PORTION, A SLEEVE MEMBER LINING THE INTERIOR WALL OF SUCH OPENING AND SUBSTANTIALLY SPACED FROM THE EXTERIOR SURFACE OF SAID SHAFT, AN INNER END MEMBER CONTAINED IN SUCH OPENING AND CLOSING THE INNER ENDS OF THE LATTER AND SAID SLEEVE MEMBER, AN OUTER END MEMBER CONTAINED IN SUCH OPENING AND CLOSING THE OUTER ENDS OF THE LATTER AND SAID SLEEVE MEMBER, SAID INNER AND OUTER END MEMBERS HAVING APERTURES WITH DIAMETERS SUBSTANTIALLY THE SAME AS THE SHAFT WHICH PASSES THROUGH THEM, AND TOGETHER WITH SAID SLEEVE MEMBER DEFINING A SUBSTANTIALLY CLOSED, CAVITY ENCLOSING SAID SHAFT WITHIN SAID OPENING, AND MEANS CONTAINED IN SAID CAVITY AND TOGETHER WITH SAID SLEEVE MEMBER AND SAID END MEMBERS FORMING A LIQUID TIGHT CONNECTION PREVENTING THE HOT MOLTEN MATERIAL IN THE RECEPTACLE PASSING THROUGH SAID WALL PORTION TO THE EXTERIOR THEREOF, SAID SHAFT, SLEEVE MEMBER AND INNER END MEMBER BEING MADE OF MATERIALS RENDERING THEM RELATIVELY INERT TO SAID HOT MOLTEN MATERIAL IN THE RECEPTACLE.