Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C13/00—Rolls, drums, discs, or the like; Bearings or mountings therefor
  • F16C13/02—Bearings
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/003—Apparatus
  • C23C2/0034—Details related to elements immersed in bath
  • C23C2/00342—Moving elements, e.g. pumps or mixers
  • C23C2/00344—Means for moving substrates, e.g. immersed rollers or immersed bearings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/30—Parts of ball or roller bearings
  • F16C33/66—Special parts or details in view of lubrication
  • F16C33/6637—Special parts or details in view of lubrication with liquid lubricant
  • F16C33/6688—Lubricant compositions or properties, e.g. viscosity
  • F16C33/6692—Liquids other than oil, e.g. water, refrigerants, liquid metal

Definitions

• the invention is in the field of surface treatment and relates to an installation for treating a strip product passing over at least one deflector roller at least partially immersed in a treatment bath such as a liquid metal or an aggressive liquid such as a acid.
• a treatment bath such as a liquid metal or an aggressive liquid such as a acid.
• the invention applies more specifically to a galvanizing installation by passing a metal strip through a bath of liquid metal, in particular molten zinc.
• the metal strip to be treated is lowered inside a bath based on liquid zinc by passing it over at least one deflector roller immersed in the bath and limited by a cylindrical envelope, the l the axis is perpendicular to the direction of travel of the strip.
• the roller is supported on two pins placed at its ends and rotatably mounted on two fixed supports spaced apart, by means of two bearings centered on the axis of the roller.
• the deflector roller extends substantially over the entire width of the tank containing the liquid metal bath.
• the two pins pass through the side walls of the tank, the support and centering bearings of the shaft thus being placed outside the bath. But the walls of the tank are pierced with holes for the passage of the pins and it is difficult to ensure the necessary seal. In addition, the position of the roller cannot be changed.
• the pins are then immersed in the bath and one cannot, generally, avoid the penetration inside the bearings of a certain quantity of the treatment liquid.
• the treatment liquid can sometimes serve as a lubricant, in particular in galvanizing installations in which the strip passes through a bath of liquid metal such as zinc. In this case, the circulation of the metal inside the bearing is encouraged.
• each pin of the roller is housed in a large orifice formed at the end of the support arm and is supported on it by means of a series of rolling elements spaced from each other so as to facilitate the circulation of metal.
• These elements are made of a ceramic material to resist corrosion and wear.
• the molten metal is found at a fairly high temperature and is often relatively aggressive and corrosive, even in the case of zinc. Since the strip normally passes over the lower part of the roller casing, it is urged upwards and the rolling elements can therefore be arranged simply on a semicircular bearing face, above of the journal.
• each pin is provided with a cylindrical seat made of ceramic and bearing on the fixed support by means of bars or half-elements circulars joined.
• a conventional type bearing comprising an internal ring threaded on the trunnion and an external ring mounted on the fixed support, between which the rolling elements are interposed.
• the active parts of the bearing are made of a composite material consisting of a sintered ceramic material and a solid lubricating material such as graphite, so as to resist corrosion and wear.
• the operating conditions generate significant constraints, related to the deformations and expansions of the various elements, which can degrade the operating quality of the roller.
• the two trunnions of the roller are held axially by stops on the ends of the support arms of the bearings which each extend downwards from a transverse beam passing over the tank and it is difficult to avoid totally vibrations.
• the liquid metal which serves as a lubricant must penetrate freely inside each bearing and, for this purpose, it is necessary to leave, between the different active parts of the bearing, clearances which increase the risks of vibration.
• the roller is provided with annular seals interposed between the fixed and rotating parts and which are provided, theoretically, to prevent any penetration liquid metal inside the bearings.
• the pins can also be fixed on the support arms, the roller then being made up of a tubular casing on which are mounted the bearings threaded on the two fixed pins.
• the sealing system which must be placed between the roller and the fixed support must consist of a set of contiguous seals covering a certain length of the trunnion which leads to limiting the length of the active part of the roller in relation to the distance between the fixed supports.
• the object of the invention is to remedy all of these drawbacks and makes it possible, in particular, to perform, at operating temperature, a self-compensation of the clearances ensuring the tightening of the bearings so as to avoid vibrations without risks of deterioration of the bearings.
• maintenance operations in particular, for the dismantling and maintenance of the bearings are facilitated.
• the invention therefore applies, in general, to a deflecting roller for a strip product moving through a bath of treatment liquid contained in a tank, said roller comprising a cylindrical envelope having an axis perpendicular to the longitudinal direction.
• each of the two bearings is housed inside an annular box surrounding the trunnion and into which the treatment liquid can penetrate, each bearing consisting entirely of elements made of a ceramic material capable of withstanding wear and corrosion of the treatment liquid and said housing is associated with bearing retention means capable of compensating for the differential expansions of the elements of the bearing relative to the housing so as to produce, at operating temperature, a tightening of the two parts of the bearing, respectively, in the housing and on the trunnion, without risk of breaking the ceramic elements.
• the box is made of a metal having a coefficient of expansion greater than that of the ceramic constituting the elements of the bearing and is associated with means for compensating for the relative expansion of the box relative to the bearing for tightening the part. external of the bearing in the box.
• each journal is made of a metal having a coefficient of expansion greater than that of the ceramic constituting the elements of the bearing and the internal part of the bearing is threaded on a smooth bearing surface of the journal with a cold mounting clearance which can be compensated in service by the differential expansions of the internal part of the ceramic bearing and of the metal journal, said clearance being determined according to the dimensions of the parts and the nature of the materials so that, at the temperature of the liquid bath, the internal part of the bearing is tightened on the trunnion without risk of breakage.
• the annular housing comprises a cylindrical side wall and two flanges each provided with a hole for the passage of the journal and the bearing retaining means comprise an interposed locking ring, with a simple clearance cold mounting, between the outer part of the bearing and the side wall of the box and made of a metal having a coefficient of expansion greater than that of the box, said ring being provided with at least one radial slot allowing circumferential elongation of the ring under the effect of expansion at operating temperature, with compensation for clearances for tightening the bearing in the housing.
• the annular locking ring consists of a series of studs each covering a circular sector and regularly distributed around the axis so as to completely surround the external part of the bearing, each stud being separated from the studs adjacent by spaces allowing the circumferential expansion of the entire ring to the operating temperature.
• the annular locking ring can be made of austenitic stainless steel and the housing of ferritic or martensitic stainless steel.
• Each stud advantageously has a substantially parallelepiped shape having a curved internal face having a radius of curvature corresponding to the external diameter of the external part of the bearing at operating temperature.
• the bearing is a rolling bearing comprising an inner ring threaded on the pin, an outer ring housed in the housing and a plurality of rolling elements interposed between the inner ring and the outer ring.
• the annular housing comprising at least one cylindrical side wall and two flanges, the means for holding the bearing in the housing include an elastic washer bearing axially, on one side on the external part of the bearing and the 'other on one of the flanges of the box for the application of the bearing against the other flange.
• the annular housing comprises at least one orifice for the passage of the journal associated with at least one filtering annular seal allowing the penetration inside the housing of the treatment liquid by blocking solid particles such as oxides or impurities, of dimensions greater than a given limit.
• each filter seal may consist of two rings threaded one on top of the other, respectively an internal ring mounted on the pin and an external ring mounted on the housing, the two rings being separated by an annular space the width of which corresponds to the limit for the passage of solid particles.
• the two rings of the filter seal are made of a ceramic material.
• the outer ring of the seal can constitute an axial holding stop bearing on the inner part of the bearing.
• the two pins are fixed, respectively on the two supports and the two boxes are threaded respectively in bores provided at the two ends of the roll, so that the latter extends over practically the entire available width between the two fixed supports.
• Each box comprises a cup closed by a cover and limited by a bottom and a cylindrical side wall, limiting a housing for the bearing and threaded without play in a bore formed at the corresponding end of the envelope of the roller, the box being provided means of elastic application of the bearing against the bottom of the cup by bearing on the cover.
• the roller is then made up of a simple cylindrical envelope surrounding a fixed shaft which connects the two support arms so as to constitute a rigid frame, the bearings being threaded on two pins provided at the two ends of the fixed shaft and each placed in a box threaded into the corresponding end of the cylindrical envelope.
• the invention can also be applied to any arrangement in which the two pins are mounted respectively at the two ends of the roller and rotate with the latter, each box then being mounted on the corresponding fixed support.
• the invention is especially applicable to a galvanizing installation in which the treatment liquid is a molten metal, in particular zinc.
• the invention can also find other applications, in particular in all cases, where the treatment liquid is a corrosive medium at a relatively high temperature, for example above 250 ° C.
• Figure 1 shows a sketch of an installation for processing a strip product.
• Figure 2 shows in cross section the installation of Figure 1.
• Figure 3 is an axial sectional view of a particular embodiment of one end of the deflector roller.
• Figure 4 is a sectional view along line IV-IV of Figure 3.
• Figure 5 is a partial front view of the bearing in Figure 4.
• Figure 1 shows schematically an installation for treating a product A in a band, comprising a tank 1 filled with a bath 10 of treatment liquid and means, not shown, for controlling the movement of product A in a band, inside of the bath 10.
• the bath 10 consists of a molten metal such as zinc.
• the product A in a band passes over a deflector roller 2 immersed in the bath 10 and leaves the bath in a substantially vertical direction.
• the deflector roller 2 is rotatably mounted on two pins 4, 4 ', by means of two bearings 3, centered on the axis 20 of the roller, which is perpendicular to the longitudinal direction D of the travel of the product A.
• the pins are formed at the two ends of the roller and therefore rotate with the latter, in bearings carried by the ends of two support arms 11, 11 'plunging into the bath.
• the two pins 4, 4 ' are fixed on the ends of two support arms 11, the bearings 3, 3' being integrated, respectively in the two ends of the roller 2
• the two pins 4, 4 ′ are preferably provided at the ends of a fixed shaft 40 which extends between the ends of the two support arms 11, 11 '.
• the deflector roller 2 then consists of a hollow cylindrical envelope in the form of a ferrule 21, threaded onto the fixed shaft 40, the two ends 4, 4 'of which form the two pins on which the two bearings 3, 3' housed are mounted. each in a box 5, 5 ′ threaded into the corresponding end of the roller 21.
• each box 5 forms an annular housing for the bearing 3, bounded by a side wall 51 and two flanges 52, 53, each pierced with a central orifice 34, 34 'for passage of the pin 4.
• the ceramic material constituting the various elements of the bearing which is expensive and relatively fragile, has, in addition, a coefficient of expansion quite lower than that of the metal used to make the different parts of the roller. There will therefore occur differential expansions between the metal parts and the bearing.
• the outer ring 31 expands less than the annular box which surrounds it and the clearances can increase with a risk of de ⁇ joining the bearing.
• the entire roller 5 is subjected to relatively high temperature conditions.
• the temperature will be of the order of 450 ° C.
• the temperature varies depending on the metal used may be lower in the case of tinning.
• the temperature parameter is a perfectly controlled element and the good thermal conductivity of the materials used, thus ensuring a homogeneous distribution of the temperature of all the elements of the roller 2 which is completely immersed in the bath of the treatment liquid. which can enter the box 5 through orifices 34, 34 ′ for passage of the pin 4.
• the envelope 21 of the roller 2 can advantageously be provided with orifices 24 allowing the treatment liquid to be introduced inside the roller, so that the whole of the roller 2, of the shaft 40 and bearings 3 bathe inside the treatment liquid.
• the operating temperature to which the various parts are subjected is thus homogeneous and substantially constant, it is possible to choose, for producing the different parts of the device, materials having different coefficients of expansion and to calculate with precision the dimensions of the parts of cold, clearances allowing easy assembly and which will be compensated, at operating temperature, by differential expansions to achieve, in service, the tightening of the bearing without risk of blocking or deterioration of the elements of the bearing.
• a rolling bearing comprising rolling elements such as rollers 33 or balls mounted on a cage 35 and interposed between a fixed internal ring 32 and an external ring. rotating 31.
• each bearing 3 which, in the example shown is of the rolling type, comprises an outer ring 31 threaded into the housing annular 5 and an internal ring 32 which is threaded on a smooth surface 41 formed on the pin 4, and abuts against a shoulder 42 of the shaft 40.
• the box 5 preferably consists of a cup 54 limited by a cylindrical wall 51 and a bottom 53, which is threaded in a bore 22 formed at the corresponding end of the envelope 21 of the roller and having an equal diameter to the external diameter of the side wall 51, apart from the mounting clearance.
• the cup 54 is provided with an annular rim forming a flange 55 which is applied against the end 23 of the cylindrical casing 21 of the roller.
• the assembly is closed by a cover 6 having a circular rim 61 which covers the flange 55 of the cup and an internal part 62 which engages in a corresponding bore 56 of the cup 54 with, when cold, the play simply necessary for the mounting.
• the entire box 5 is thus integrated into the end of the casing 21 and removably fixed thereto by screws 24 bearing on the peripheral flange 61 of the cover 6.
• this method of fixing does not is provided as a safety measure because, according to the invention, differential expansions are used to achieve perfect joining, hot, of the various parts between which are provided, cold, the necessary mounting clearances.
• the cup 54 of the housing 5, which is threaded into the bore 22 of the casing 21, can be made of the same metal as the latter, for example a ferritic or martensitic stainless steel.
• the cover 6, the part 62 of which is threaded into the bore 56 of the cup 54 is preferably made of a metal having a slightly higher coefficient of expansion, for example an austenitic stainless steel. So the differential expansions determine a blockage of the whole of the box on the casing 21 at the service temperature while, when cold, it is possible to leave, between the parts, a minimum clearance allowing easy assembly and disassembly.
• the bearing 3 comprises an internal ring 32 threaded onto the bearing surface 41 of the pin 4. This is made, like the shaft 40, of a stainless steel whose coefficient of expansion is higher than that of the ceramic.
• the relative diameters of the bearing surface 41 and of the inner face of the internal ring 32 are therefore determined so as to benefit from a clearance when cold, which facilitates mounting and is canceled at bath temperature 10 by the relative expansion of the pin 4. , this clearance being, however, calculated as a function of the temperature and of the nature of the materials so that the tightening stresses resulting from the expansion are not excessive and do not risk causing the internal ring 32 to break.
• the expansion of the housing 5 is greater than that of the outer ring 31 of the bearing 3 and could determine a clearance resulting in the loosening of the bearing and a risk of vibrations.
• the bearing 3 is held radially in the housing of the box 5 by a locking ring 8 interposed between the outer ring 31 and the side wall 51 and made of a metal whose coefficient is higher than that of the box, for example an austenitic stainless steel, the housing being made of ferritic steel.
• this ring 8 therefore tends to increase and compensate for the relative expansion of the side wall 51, by determining a tightening of the bearing which is, however, limited so as to avoid the risk of the ceramic parts and to keep the functional clearance necessary for the bearing to roll.
• the ring 8 is provided with at least one slot making it possible to absorb the expansion of the ring 8, which occurs essentially in the circumferential direction.
• the locking ring 8 consists, as shown in FIG. 4, of a series of studs 81 arranged one after the other, each stud being separated from the adjacent studs by a space 82 .
• Each stud 81 has a substantially parallepipedic shape and covers a circular sector so that the curved faces of the successive studs coming into contact with the outer ring 31 of the bearing 3 and the inner face of the cup 54 are tangentially connected to reconstitute an annular ring of which the circumferential length can vary thanks to the spaces 83 left between the studs.
• the latter are centered separately on the bottom 53 of the box 5, each by a pin 84 which engages in a corresponding bore formed in the bottom 53.
• the studs 81 are thus maintained and distributed uniformly in the cup 54, around the outer ring 31.
• the cold mounting of these pins 24 is produced with a clearance determined so as to be compatible with the differential expansions of the constituent elements at temperature Operating.
• the curved internal face 85 of each stud is given a radius of curvature equal to that which is reached, at operating temperature, by the external face of the external ring 31. Taking account of the expansions, a distribution is thus ensured uniform tightening stresses over the entire periphery of the bearing 3.
• the rolling elements 33 interposed between the inner ring 32 and the outer ring 31 of the bearing 3 can be spherical balls or else rollers whose profile is advantageously determined to allow angular deflection in the event of misalignment between the pins 4, 4 'and the envelope 21 of the roller 2.
• the rolling elements may have a cylindrical shape rounded at its ends or else a barrel shape.
• the orifices 34, 34 'formed respectively on the cover 6 and the bottom 53 of the housing 5 for the passage of the pin 4 are each provided with a filtering joint 7, 7' consisting of two rings threaded one inside the other with a small clearance which lets the liquid metal pass by retaining solid particles or impurities of dimensions greater than the thickness of said clearance and corresponding to a given limit.
• the filter seal 7 comprises a ring 71 threaded onto the bearing surface 41 of the pin 4 and a ring 72 mounted on the cover 6 of the box.
• the filter seal 7 ′ comprises a fixed ring 71 ′ threaded on the shoulder 42 of the shaft 40 and a rotating ring 72 ′ mounted on the periphery of the orifice 34 ′ formed on the bottom 53 of the cup 54.
• the two pairs of rings 71, 72 and 71 ', 72', constituting, respectively, the two filter seals 7, 7 ' are preferably made of a ceramic material of the same kind as the bearing 3.
• the latter is applied against the bottom 53 of the cup 54 by an elastic washer 63 which is centered on the ring rotating 72 and comes to bear, on one side on the cover 6 of the housing 5 and on the other on the outer ring 31 of the bearing 3 whose inner ring 32 is applied against the shoulder 42 of the shaft 40.
• the ring 72 makes it possible to limit the axial displacement of the envelope 21 of the roller with respect to the pin 4 and thus ensures the function of axial stop.
• annular space 73 which is left between the fixed ring 71 and the rotating ring 72 allows the circulation of the liquid metal inside the housing but has a thickness reduced enough to ensure filtration of the oxides and impurities contained in metal. We can thus avoid the introduction inside the box of iron and zinc alloys, called “dross" which would tend to settle between the active parts of the bearing.
• the rotating rings 72, 72 ′ may be provided, on their inner faces, with helical engravings oriented so as to cause the liquid to circulate towards the outside of the bearing housing. In this way, the confinement of the zinc is avoided inside the housing and the oxides or impurities which could have formed there are evacuated before being able to gain weight.
• the fixed and rotating parts of the roller are normally made of stainless steel.
• the casing 21 of the roller 2, the shaft 40, and the cup 54 of the box are made of ferritic or martensitic stainless steels, the cover 6 can itself be austenitic stainless steel, as well as the studs 23, constituting the clamping ring.
• All the elements of the bearing 3 as well as all of the rings 71, 72, 71 ', 72', forming seals are made of ceramic.
• the installation enables galvanization to be carried out.
• the treatment bath is based on liquid zinc and the operating temperature is generally between 445 ° C and 460 ° C and must not exceed 480 ° C.
• the treatment bath is tin-based and its operating temperature is generally between 250 ° C and 300 ° C.
• the treatment bath may be based on lead, at a temperature between 330 ° C and 350 ° C, or based on nickel, at a temperature of the order of 450 ° C, or also based on aluminum, at a temperature above 650 ° C.
• the invention is obviously not limited to the details of the embodiments described above but also covers the variants employing equivalent means and remaining within the scope of the protection defined by the claims.
• the pins are fixed, the bearings being integrated, with their housing, in the ends of the roller.
• the invention can however be applied to the reverse arrangement, in which the pins formed at the two ends of the roller rotate with the latter, the bearings then being housed in the boxes fixed to the fixed supports.
• the invention could be applied to other types of bearings, for example, plain bearings simply comprising two rings threaded one into the other and associated with means for ensuring the circulation of the liquid metal between the fixed part and the rotating part.
• the invention could be applied to other installations comprising one or more rollers immersed in a treatment liquid for example for acid pickling or electrolysis treatment.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Coating With Molten Metal (AREA)
• Rolls And Other Rotary Bodies (AREA)

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Publications (1)

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Citations (8)

• 1995
  • 1995-06-15 FR FR9507159A patent/FR2735499B1/fr not_active Expired - Fee Related
• 1996
  • 1996-06-17 AU AU63625/96A patent/AU6362596A/en not_active Abandoned
  • 1996-06-17 WO PCT/FR1996/000931 patent/WO1997000334A1/fr not_active Application Discontinuation
  • 1996-06-17 CA CA002220029A patent/CA2220029A1/fr not_active Abandoned
  • 1996-06-17 EP EP96922937A patent/EP0833955A1/fr not_active Withdrawn
  • 1996-06-17 JP JP9502732A patent/JPH11507701A/ja active Pending

Patent Citations (8)

Non-Patent Citations (5)

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