Spin-Drying Process and Spin-Drying Installation

This application claims priority pursuant to 35 U.S.C. 119 (a) to French Application No. 2406783, filed Jun. 24, 2024, which application is incorporated herein by reference in its entirety.

The present invention relates to industrial facilities, in particular rolling mills, using a lubricant.

More precisely, according to a first aspect, the present disclosure relates to a method for drying a rolled strip.

The method for drying a rolled strip comprises supplying a drying facility comprising two hydrodynamic pads, respectively extending in length over a width of the rolled strip, advancing rolled strip between two hydrodynamic pads in an advancement direction defined from upstream to downstream, applying pressure of the hydrodynamic pads, one towards the other, on either side of the rolled strip, following a clamping plane transverse to the strip, during the advancement of rolled strip, the hydrodynamic pads sliding on the rolled strip by means of a layer of fluid, each of the hydrodynamic pads carrying out a first drying operation by blocking at least one portion of a lubricating layer of the strip coming from upstream towards downstream, and sucking in, via a suction orifice located downstream of the hydrodynamic pads, at least a portion of a residual fluid layer, thus performing a second drying operation of the strip. An associated drying facility is also disclosed.

According to a second aspect, the present disclosure relates to a drying facility that can implement the method according to the first aspect.

Rolling mills are industrial machines which can carry out a rolling operation, which is a method for manufacturing a strip of material, in particular metal, by plastic deformation. The strip, generally of low thickness relative to its length and width, is driven in translation and compressed between at least two rollers located on either side of the thickness of the strip. Through this operation, the thickness of the strip is reduced, but also made more uniform over the entire length of the strip.

Such an operation can be implemented at very high rates, which may involve very fast linear strip speeds. The forces concerned, as well as these considerable speeds, involve the use of very high quantities of lubricant. For example, a possible lubricant flow rate for such applications can be of order several thousand litres per minute. Reference is made to the “lubricant”, but it is understood that this term designates a liquid which can fulfil the functions of both lubrication and cooling. Typically, it can involve a mixture comprising oil.

Use of lubricant in such quantities requires at least one drying operation, in other words an operation consisting of removing from the strip a satisfactory quantity of lubricant, in order that the strip is ready for a next industrial step, for example cutting or packaging. In other words, it is necessary that almost no trace of lubricant remains on the strip leaving the rolling mill. Furthermore, it is very difficult to manage unintended projections of lubricants for which the quantities used are large.

For these drying operations, it is known to use so-called “roller dryers”. These dryers use one or more rollers which come into contact with the strip, on either side thereof, in such a way as to block the lubricant which then leaves on the lateral sides of the strip. Two types of “roller dryers” can be distinguished for applications on such rolling mills:

However, these two types of so-called “roller” dryers also have disadvantages which relate to the efficiency of the drying, although the small-roller dryer is more efficient, the drying remains imperfect and drops of lubricant can subsist in particular at the edges of the strip leaving the dryer. This excess of lubricant at the strip edges then contaminates a larger area of strip when it is wound into a reel.

The contact with the one or more rollers, inevitable due to the same operating principle of these dryers, can also leave undesirable marks on the strip. This phenomenon is particularly harmful when it concerns rolled strips for which the surface state must be impeccable, for example for stainless steel strips for which a “mirror” shine is expected on their faces for certain products.

In addition, such rollers wear relatively quickly due to their contact with the strip, and need to be inspected, then possibly changed. Moreover, the wear of the rollers can accentuate the potential disadvantage of undesirable marking of the strip and can also reduce the efficiency of drying.

Therefore, the object of the present disclosure is to overcome at least some of the disadvantages of the prior art.

According to a first aspect of the present disclosure, the objectives mentioned above are attained by a method for drying a rolled strip, the method comprising:

Thus, in a particularly effective manner, the strip is dried without any contact with any part of the drying facility. More specifically, the sliding of the hydrodynamic pads on the layer of fluid can ensure, by blocking, a first drying operation without contact between the pads and the strip, thus preserving the surface condition of the strip and minimising the wear of the pads. The layer of fluid necessary for sliding of the pads, which is significantly reduced relative to the layer of fluid present upstream of the drying facility, is then sucked in via the suction orifice. Thus, the strip has, when leaving the dryer, a sufficiently low quantity of lubricant to pass to the following industrial step.

According to optional features, the present disclosure according to the second aspect can have the features outlined in the following paragraphs, which can optionally be implemented independently of one another or in combination with one another:

According to an embodiment, the method comprises a temporary or continuous injection of a supply fluid between the rolled strip and the hydrodynamic pads, the injection being carried out by means of one or more supply orifices provided in the hydrodynamic pads or by supply nozzles upstream of the hydrodynamic pads, the injection of the supply fluid being carried out in such a way as to ensure the presence of the layer of fluid by means of which the hydrodynamic pads slide on the strip, ensuring a gap between the rolled strip and the hydrodynamic pads, on each side of the strip, the supply being of oil, or of an emulsion comprising air and oil.

According to an embodiment, the method comprising: blowing, via a blowing orifice located downstream of the suction orifice, a projection fluid, such as air, in particular hot air, or steam, towards the strip in such a way as to detach, from the strip, at least a portion of the residual layer of lubricant and to project it towards the suction orifice.

According to an embodiment, the method comprising evacuating at least a portion of the lubricating layer blocked by the drying stages, beyond the lateral edges of the rolled strip.

According to a second aspect, the present disclosure relates to a drying facility which can be suitable for implementing the method for drying a rolled strip according to the first aspect, the drying facility comprising:

According to an embodiment, the facility can comprise at least one supply orifice or at least one supply nozzle configured to carry out a temporary or continuous injection of a supply fluid (such as oil or an oil and air emulsion) between the rolled strip and the hydrodynamic pads, the at least one supply orifice being provided in the hydrodynamic pads or the at least one supply nozzle being located upstream of the hydrodynamic pads, the injection of the supply fluid being carried out in such a way as to ensure the presence of the layer of fluid by means of which the hydrodynamic pads slide on the strip, guaranteeing a gap between the rolled strip and the hydrodynamic pads, on each side of the strip.

According to an embodiment, the facility can comprise at least one projection orifice located downstream of the suction orifice, the projection orifice being configured to project a projection fluid (such as air, in particular hot air, or even steam) towards the strip in such a way as to detach, from the strip, at least a portion of the residual layer of lubricant and to project it towards the suction orifice.

According to an embodiment, the hydrodynamic pads having an elongate shape and extending continuously over the entire width of the strip and beyond the lateral edges of the strip.

According to an embodiment, the at least one suction orifice can comprise a suction slot provided in the direction of the width of the strip, continuously covering at least the entire width of the strip, in such a way as to produce a suction knife.

According to an embodiment, the at least one projection orifice can comprise a projection slot provided in the direction of the width of the strip, continuously covering at least the entire width of the strip, in such a way as to project a knife of projection fluid.

According to an embodiment, the facility can comprise at least one pair of two cassettes provided facing one another on either side of the strip, each cassette comprising one of the hydrodynamic pads, in particular the at least one supply orifice or the at least one supply nozzle, and the at least one suction orifice, each cassette being movable in translation relative to one another and relative to the strip in a direction normal to a plane formed by the strip, in such a way as to exert a pressure on the supply fluid injected between each drying stage and the strip, each of the at least one supply orifice or the at least one supply nozzle and of the at least one suction orifice fluidically communicating with respectively a supply line and a suction line provided in each cassette, the drying facility comprising at least one pair of transverse beams extending in the direction of the width of the strip, each cassette being removably mounted in translation along one of the transverse beams. In particular, each cassette can comprise the at least one projection orifice, the at least one projection orifice fluidically communicating with a projection line provided in the cassette. In particular, each of the cassettes comprises a cover which can be a separate part attached on the cassette, the projection slot being obtained by forming a clearance between the cassette and the cover.

According to an embodiment, the at least one projection orifice is oriented at an angle α with the strip, with a value less than 90°, preferably between 90° and 70°, in particular between 90° and 80°, such as 85°.

The drawings and the description hereinafter essentially contain elements of a certain nature. Hence, they could not only be used to better understand the present disclosure, but also contribute to the definition thereof, where appropriate.

In the various figures, the same reference signs designate identical or similar elements. For conciseness, only the elements which are useful for understanding the described embodiment are shown on the figures and are described in detail below.

In the following description, when referring to qualifiers of absolute position, such as the terms “front”, “rear”, “high”, “low”, “left”, “right”, etc., or relative position, such as the terms “above”, “below”, “upper”, “lower”, etc., or qualifiers of orientation, such as “horizontal”, “vertical”, etc., reference is made, unless otherwise specified, to the orientation of the figures or of a rolling-mill drying facility in its normal position of use. Furthermore, the term “substantially” should be interpreted as indicating that the result obtained is as precise as the method known for measuring it.

The drying facility is typically positioned downstream of a rolling mill, for example a rolling mill with 20 cylinders, as shown in, and including:

The pressing roller assemblies are typically mounted with eccentric systems, which can ensure clamping of the strip, or even ensure control of the camber of the cylinders, including the cambers of the working cylinders.

By controlling the camber, it is possible to give a strip profile to the rolled strip, which can be rectilinear, or even, very often, curved.

Such a rolling mill generally includes four manifoldsfor spraying lubricant, typically a mixture of oil and water, at the working cylinders. Two manifolds are disposed, on the embodiment shown in, in the upper portion, on one side of the rolled strip, and two manifolds in the lower portion on the other side of the rolled strip. Each manifold including, along its length, transverse to the strip, a series of nozzles, ensuring spraying of lubricant over the width of the strip, and/or on the rollers of the rolling mill.

The embodiments of the drying facilitydisclosed in the present document are not limited to being used only in the presence of a rolling mill with 20 cylinders, as shown in, which is only shown by way of example, but for use in any strip rolling mill industrial facility using a lubricant.

Reference is now made to, which shows a schematic representation of a drying facilityaccording to an example of the present disclosure, located downstream of a rolling mill, for example a rolling mill of the previously described type. The drying facilityis passed through by the rolled stripadvancing in an advancement direction V as defined using an arrow in the figure, from upstream to downstream, after having passed through the rolling mill.

The rolled stripcan typically comprise steel, for example stainless steel. The rolled stripcan also be a magnetic sheet, comprising an iron-silicon alloy. These examples of materials are given by way of example and are not limiting, the solutions according to the present disclosure are suitable for any rolled strip using a lubricant.

The rolled stripcan have a width between 750 mm and 1650 mm. The rolled stripcan have a thickness, leaving the rolling milland thus entering the drying facility, between 0.15 and 3.5 mm.

The rolled strip typically comprises two main surfaces, an upper and a lower surface. The main surfaces are defined as being the surfaces joining the two lateral edges,of the strip. These main surfaces form a plane, hereinafter defined as being the plane of the strip.

The drying facilityis mounted on a fixed structure, for example integral with a frame of a rolling mill (not shown) located upstream of the drying facility. The fixed structureis fixed relative to the rolled strip.

In this case, the drying facilityincludes two cassettesmounted to be movable relative to the fixed structure, each cassette advantageously including elements participating in the drying operation which will be described below. The fixed structureincludes an actuator configured to drive each of the cassettesin translation relative to the fixed structure. The translation of the cassettesis effected along a direction perpendicular to the plane formed by the strip. More precisely, each cassetteis removably mounted on a transverse beam, the transverse beambeing connected to the actuator. Thus, it is possible to carry out control or maintenance operations on a cassetteby withdrawing it from the facility, without having to dismantle more parts than necessary. It is also possible that each cassetteis directly mounted on the actuator, according to the examples.

More particularly, the actuator is configured to enable the cassettesto each apply a pressing force, together resulting in a clamping force, on the rolled strip, or more precisely on a layer of fluid of the rolled strip. The cassettesare thus positioned oppositely, facing one another, so that their respective clamping forces are applied in opposite senses in the same direction. Thus, their actions “cancel” and do not fold or deform the strip. In other words, each of the cassettes applies a pressing force, in a clamping plane perpendicular to the plane formed by the strip. In particular, the clamping plane is transverse to the strip. The clamping plane comprises the translation direction of the cassettes.

The upper fixed structureincludes hydraulic cylinders,configured to drive the upper cassette.in translation, guided for example as shown by two guide bars,, provided in clamping plane. The actuator is controlled by a controller (not shown). The controller can be configured to control the speed of translation of the cassettes, and/or to control the pressing force of the cassetteson the strip.

Similarly, the lower fixed structure includes hydraulic cylinders (not shown) configured to drive the lower cassette.in translation, guided for example by two guides which are not visible in the figure, provided in clamping plane. The actuator is controlled by a controller (not shown). The controller can be configured to control the speed of translation of the cassette, and/or to control the pressing force of the cassetteson the strip. Reference is now made to, which show cross-sectional views of the drying facilityaccording to two separate examples of the present disclosure.

In, the rolled stripis shown, advancing in the advancement direction V between two cassettes, one being the so-called upper cassette.and the other being the lower cassette., each being removably mounted on upper.and lower.transverse beams respectively.

According to the examples, and as shown in these Figures, each of the cassettesincludes a hydrodynamic pad. The hydrodynamic padis positioned directly opposite the strip. The hydrodynamic padhas a substantially planar working surface, disposed facing the strip. The working surfaceextends in a plane substantially parallel to a plane formed by the strip. The working surfaceis substantially perpendicular to the clamping plane.

The hydrodynamic padhas a generally rectangular cross-section, having two rounded edges,adjacent to the working surface. Each hydrodynamic padalso has a front sideand a rear side. The front side, in the examples, contributes to the blocking of a quantity of lubricant located upstream of the hydrodynamic pads. These elements can be seen in.

The hydrodynamic padsextend in length over a width of the strip. As is particularly visible in, the hydrodynamic padsextend at least beyond the lateral edges,of the strip, for example by a distance d, greater than or equal to 30 mm.

According to the examples, and as shown in, the drying facility can include at least one supply orifice. In some examples, each cassetteincludes at least one supply orifice. The at least one supply orificeis configured to produce an injection of supply fluid, in such a way as form a layer of fluid between each hydrodynamic padand the strip. The at least one supply orifice, in some examples, is arranged opening on the hydrodynamic pad. In particular, the at least one supply orifice can be arranged on the working surfaceof the hydrodynamic pad.

In some examples, the drying facilityincludes a plurality of supply orifices, arranged opening on the working surface of hydrodynamic pads. In some examples, and as shown in, the supply orificesare distributed, regularly or otherwise, over the length of each hydrodynamic pad. Here, the supply orificesare distributed regularly. The supply orificesare, preferably, arranged in such a way as to cover the entire length of the hydrodynamic pads, themselves being of sufficient length to cover at least the entire width of the strip. It is possible to not provide a supply orificeat the two longitudinal ends of the hydrodynamic pads, these ends extending beyond the strip. For example, these ends can be devoid of any supply orificeover a distance at least greater than the distance d.