Device for heating or cooling a substantially planar surface by blowing a gaseous fluid

Abstract

The present invention relates to devices for blowing a gaseous fluid onto a flat surface Sp. The device according to the invention comprises a pressurized gaseous fluid container 10, with at least one flat front face portion 13, a hollow tube 20 defined between two proximal ends 21 and distal ends 22, an inlet opening 23 located at end 21 defining an opening axis 24, an outlet opening 25 located at end 22 defining an opening axis 26, the hollow tube 20 having a curvature such that the two axes 24, 26 form a non-zero angle α with each other, and means 30 for fixing the proximal end 21 to the flat face portion 13 arranged such that the inlet opening axis 24 is substantially perpendicular to the flat face portion. Applications include, in particular, heating / cooling metal strips in annealing and coating furnaces.

Description

[0001] The present invention relates to devices for heating or cooling a substantially flat surface by blowing a gaseous fluid onto it, which find a particularly advantageous application in the field of heating and / or cooling metal strips which pass through heat treatment furnaces, for example annealing furnaces often known by technicians as "lines", coating furnaces or the like.

[0002] Blowing a gaseous fluid onto metal strips, whether moving or not, whether to heat or cool them, such as when leaving a bath after galvanizing, poses serious problems, in particular those explained in patent EP 2085488.

[0003] This prior document describes and illustrates a device for blowing a gaseous fluid onto a preferably flat strip, which attempts to solve many of these problems.

[0004] This prior device comprises at least one box constituting a source volume of the gaseous fluid, for example pressurized air, this box comprising at least one portion of flat front surface which is capable of being positioned directly opposite the strip, and at least one hollow tube or tubular nozzle.

[0005] This hollow tube or tubular nozzle has a proximal end, a distal end, an inlet opening located at the proximal end and defining an inlet opening axis, an outlet opening located at the distal end and defining an outlet opening axis which, the tube being rectilinear, is collinear with the inlet opening axis.

[0006] Further provided are means for securing the proximal end of the hollow tube to the planar face portion to connect the gaseous fluid source volume within the hollow tube via an orifice provided in the planar face portion.

[0007] However, as described in this prior document and illustrated in particular in the figures of this document, namely the figures 1 , 2 and 5 to 12, so that the outlet opening axis of the tube makes, with the flat surface, an angle other than 90 degrees of angle, for example 75 degrees of angle to obtain an oblique blowing on the strip which makes it possible to obtain good results in terms of stabilization of the strip over its entire width subjected to such heating or cooling, it was necessary to produce boxes comprising a front surface, that facing the strip, the profile of which is variable in at least one given direction.

[0008] Other documents describe similar devices which are also not satisfactory. Examples include EP 2869011 and US 2003 / 226276.

[0009] More specifically, it can also be cited as the US 20101269367 .

[0010] However, in all the prior documents cited above, none of the devices described makes it possible to obtain optimal cooling of the strip in order to avoid the formation, on this strip, of defects which could harm its proper manufacture and subsequently its use.

[0011] For example, the last US document cited above teaches a blowing system whose jet is perpendicular to the strip, which does not allow for uniform cooling, since it does not allow for the safe and rapid evacuation of all the calories delivered by the strip just as it leaves the furnace. Indeed, a jet perpendicular to the strip can produce more cooling on its sides than in its center, and therefore not uniform.

[0012] Also, the present invention aims to provide a device for blowing a gaseous fluid onto a flat surface or strip, which largely overcomes the drawbacks mentioned above of similar devices of the prior art, by having a structure which, while homogenizing the transverse profile of the strip obtained at the outlet of the blowing section, allows, by a homogeneous evacuation of calories without risk of leaving part of them at the level of the hot strip, to optimize them its manufacture and for this reason to obtain a manufacturing and maintenance cost price much lower than that of similar devices of the prior art.

[0013] More specifically, the present invention relates to a device for blowing a gaseous fluid onto a flat surface, as defined in the appended claim 1, and specified in the dependent claims.

[0014] Other characteristics and advantages of the present invention will appear during the following description given with reference to the attached drawing for illustrative purposes, but in no way limiting, in which: The single figure represents a schematic longitudinal sectional view of a preferred embodiment of the device according to the invention for heating or cooling a substantially flat surface by blowing a gaseous fluid onto it.

[0015] It is specified that, in this description, if the adverb "substantially" is associated with a qualifier of a given means, this qualifier must be understood in the strict or approximate sense.

[0016] With reference to the single appended figure, the present invention relates to a device for blowing a gaseous fluid onto a flat surface Sp, for example a hot metal strip passing through the rapid cooling section of an annealing furnace.

[0017] This device comprises a box 10 constituting a source volume 11 of the pressurized gaseous fluid, such as air or the like. It is clearly specified that the box 10 can be made from a single piece defining a volume or from a combination of several pieces together defining the same volume.

[0018] This box comprises a front face 12 comprising at least one portion of flat face 13 capable of being positioned opposite the flat surface Sp so that this portion of flat face 13 is capable of being substantially parallel to the flat surface Sp and directly opposite it.

[0019] Such a box may have different shapes, for example that of a parallelepiped or the like, or even the shape of a duct of circular, oval or similar section, for example cylindrical of revolution. In the latter case, the portion of flat face 13 defined above, which is a portion of the lateral surface of the duct, is curved. But it can nevertheless be considered as flat, taking into account the proportions between the cross-section of the hollow tube 20 (nozzle) defined below and that of the box-duct, this portion of flat face 13 then being able to be constituted by a portion of tangent plane at a point of the lateral wall of the circular box-duct which is directly opposite the flat surface or strip Sp.

[0020] As mentioned above, the device further comprises at least one hollow tube 20 (in reality, it comprises a plurality of them) having a proximal end 21, a distal end 22, an inlet opening 23 located at the proximal end 21 and defining an inlet opening axis 24, and an outlet opening 25 located at its distal end 22 and defining an outlet opening axis 26.

[0021] By "opening axis", within the meaning of this description, is understood a direction of rectilinear axis defined by the axis of an end portion of the hollow tube considered as rectilinear over a short length.

[0022] The device further comprises means 30 for fixing the proximal end 21 of the hollow tube (or blowing nozzle) to the flat face portion 13, for connecting the source volume 11 to the interior of the hollow tube 20 via an orifice 14 made in the flat face portion.

[0023] According to an essential characteristic of the invention, the hollow tube 20 comprises at least one curved portion, for example a curved portion 200 (or a succession of curved portions) between two rectilinear tube portions, as illustrated in the single figure. This curved portion can also be constituted by the tube in its entirety curved between its two ends 21, 22.

[0024] This curved portion is defined so that the two axes 24, 26 respectively of the inlet 23 and outlet 25 openings form between them, a single figure, a non-zero angle α.

[0025] According to another essential characteristic of the invention, the means 30 for fixing the proximal end 21 of the hollow tube to the flat face portion 13 are arranged so that the inlet opening axis 24 is substantially perpendicular to this flat face portion 13.

[0026] Although they can be produced in different ways, according to a particularly advantageous embodiment in terms of industrial manufacturing, the means 30 for fixing the proximal end 21 to the flat face portion 13 are constituted by a sleeve 31 comprising an axial through-hole 32, first means for fixing the proximal end 21 of the hollow tube 20 to a first end 33 of the through-hole 32, and second means for fixing this sleeve 31 to the flat face portion 13 so that the second end 34 of the through-hole 32 is in direct fluid communication with the source volume 11 via the orifice 14.

[0027] According to a possible embodiment, the hollow tube 20 and the sleeve 31 are made in a single piece. However, for reasons of manufacturing and maintenance in particular, they are made in two separate pieces, as illustrated, and the first and second fixing means defined above consist of a male part fitting into a female part.

[0028] Thus, in the illustrated embodiment, the male part of the fitting for fixing the proximal end 21 of the hollow tube 20 to the first end 33 of the through-hole 32 is constituted by a portion 27 of this end 21 of the hollow tube, this portion 27 of the proximal end of the tube being advantageously of cylindrical shape of revolution.

[0029] As for the female part of this fitting, it is constituted by a counterbore 28 whose section is complementary to that of the portion 27 of the proximal end of the tube, this counterbore 28 being produced coaxially with the first end 33 of the through-hole 32.

[0030] The male part of the fitting for fixing the sleeve 31 to the flat face portion 13 is constituted by the portion 29 of the sleeve 31 which surrounds the second end 34 of the through-hole 32, this portion 29 of the sleeve having a cylindrical shape advantageously of revolution, and the female part of this fitting is constituted by the orifice 14 which has a section complementary to that of the portion 29 of the sleeve which surrounds the second end 34 of the through-hole 32.

[0031] After they have been made, the two sockets described above can be completed, for safety, by welding or the like.

[0032] Advantageously, the through-hole 32 of the sleeve 31 has a shape which in particular makes it possible to minimize the pressure loss of the flow of the fluid under pressure in this through-hole. The single figure represents, as an example among others possible, an advantageous shape of such a through-hole, namely the shape of a truncated cone or the like whose small base is turned towards the proximal end 21 of the hollow tube 20.

[0033] As mentioned in the preamble to the present description, the invention finds a particularly interesting application in the cooling of a metal strip over a temperature range of 1180°C to 220°C passing through an annealing furnace, or of 440 / 680°C at the outlet of a coating bath. In this case of application, according to a characteristic of the invention, the angle α formed between the two axes 24, 26 respectively of the inlet 23 and outlet 25 openings, is chosen between 3 and 30 degrees of angle, limits included.

[0034] According to a very preferred embodiment which has given, during experimental tests, very good results, the ratio between the value of the internal diameter of the outlet opening 25 and the distance between this outlet opening 25 and the flat surface Sp is substantially equal to 1 / 5 (one in five).

[0035] During these experiments, it was also found that the ratio between the area of ​​the second end 34 of the axial through-hole 32 and that of the outlet opening 25 is at least equal to three, for example for a tube length of between 30 mm and 300 mm.

[0036] A blowing device comprising only one hollow tube or nozzle associated with the box has been described above. However, as explained and illustrated in particular in the prior document referenced in the preamble to this description, such a device is generally designed to comprise several such hollow tubes.

[0037] However, in the case where the device comprises at least two hollow tubes 20 successively associated with the box 10, substantially identical and associated with this box in an identical manner, the ratio between the distance separating the two inlet opening axes 24 of the two hollow tubes 20 and the distance separating the outlet openings 25 and the flat surface Sp is very preferably substantially equal to 7 / 5 (seven out of five).

[0038] The device according to the invention has numerous advantages over similar devices of the prior art, for example the advantages cited below by way of non-limiting example: homogenization of heating or cooling across the entire width of the moving strip. the box (or boxes) and the hollow tubes or nozzles can all be of the same shape and have the same dimensions, since they do not need to be differentiated as in the prior art, either in their manufacture or in their implementation. They can therefore be interchanged without problem, by choosing them from the plurality. As they are all identical, their manufacturing and supply cost is relatively low, the maintenance operations of the device are simplified and the cost of this maintenance is greatly reduced compared to that for the prior devices. the structure of a hollow tube 20 (or nozzle) according to the invention with its connection to the box by means of a sleeve 31 by fittings as defined above, allows it to be associated with the flat face wall 13 very easily and quickly, according to all possible angular positions over 360 degrees of angle. This assembly operation facilitates the maintenance of the device in all circumstances, even if welding points or the like may also be provided to secure the fitting attachments. the structure of this hollow tube 20 (or nozzle) makes it possible to very considerably reduce the flow pressure losses of the gaseous fluid. A reduction in these losses of approximately 20 to 30% has been observed.

[0039] The operation and use of the device according to the invention will not be described specifically, since they can be deduced without any difficulty from the description, given in the prior document referenced in the preamble, of the prior similar device.

Claims

1. Device for blowing a gaseous fluid on a planar surface (Sp) for its heating or its cooling, comprising: • a box (10) constituting a source volume (11) of said pressurised gaseous fluid, said box comprising a front face (12) comprising at least one planar face portion (13), this planar face portion being capable of being positioned facing said planar surface (Sp), such that this planar face portion (13) is substantially parallel to the planar surface (Sp) and directly facing it, • at least one hollow tube (20) comprising a proximal end (21), a distal end (22), an inlet opening (23) located at the proximal end (21) and defining an inlet opening axis (24) and an outlet opening (25) located at the distal end (22) and defining an outlet opening axis (26), and • means (30) for fixing said proximal end (21) of the hollow tube to said planar face portion (13), to connect the source volume (11) to the inside of said hollow tube (20) via an orifice (14) made in the planar face portion, characterised in that: • said hollow tube (20) comprises at least one curved portion (200), such that the two respectively inlet opening (23) and outlet opening (25) axes make between them, a non-zero angle (α), and that • the means (30) for fixing said proximal end (21) to said planar face portion (13) are arranged, such that the inlet opening axis (24) is substantially perpendicular to said planar face portion.

2. Device according to claim 1, characterised in that said curved portion (200) is constituted by the hollow tube (20) entirely curved between its two proximal and distal ends (21, 22).

3. Device according to any one of claims 1 and 2, characterised in that the means (30) for fixing said proximal end (21) to said planar face portion (13) arranged such that the inlet opening axis (24) is substantially perpendicular to said planar face portion (13) are constituted by: • a sleeve (31) comprising an axial through bore (32), • first means for fixing the proximal end (21) of the hollow tube (20) to a first end (33) of said axial through bore (32), and • second means for fixing said sleeve (31) to said planar face portion (13), such that the second end (34) of the axial through bore (32) directly fluidically communicates with said source volume (11) via said orifice (14).

4. Device according to claim 3, characterised in that at least one of said first and second fixing means are constituted by an interlocking of a male part in a female part.

5. Device according to claim 4, characterised in that: • the male part of the interlocking for fixing the proximal end (21) of the hollow tube (20) to the first end (33) of said axial through bore (32) is constituted by a portion (27) of the proximal end (21) of the tube (20), said portion (27) of the proximal end of the tube being advantageously cylindrical revolving-shaped, and the female part is constituted by a counterbore (28), the cross-section of which is complementary to that of said portion (27) of the proximal end of the tube, said counterbore (28) being made at the first end (33) of the axial through bore (32), and that • the male part of the interlocking for fixing the sleeve (31) to the planar face portion (13) is constituted by the portion (29) of the sleeve (31) which surrounds the second end (34) of the axial through bore (32), this portion (29) of the sleeve having a cylindrical, advantageously revolving, shape, and the female part is constituted by said orifice (14) which has a cross-section complementary to that of the portion (29) of the sleeve which surrounds the second end (34) of the axial through bore (32).

6. Device according to any one of claims 3 to 5, characterised in that said axial through bore (32) has substantially the shape of a truncated cone, the small base of which is facing the proximal end (21) of said hollow tube (20).

7. Device according to any one of the preceding claims, characterised in that said angle (α) ) that therebetween form the two axes (24, 26) respectively of the inlet (23) and outlet (25) openings, is chosen between 3 and 30 degrees, limits included.

8. Device according to any one of the preceding claims, characterised in that the ratio between the value of the inner diameter of the outlet opening (25) and the distance comprised between this outlet opening (25) and the planar surface (Sp) is substantially equal to 1 / 5.

9. Device according to any one of the preceding claims, characterised in that the device comprises at least two successive hollow tubes (20) substantially identical to and associated with said box (10) identically, the ratio between the distance separating the two inlet opening axes (24) of the two hollow tubes (20) and the distance separating the outlet openings (25) and the planar surface (Sp) is substantially equal to 7 / 5.

10. Device according to any one of the preceding claims, when it depends on claim 3, characterised in that the ratio between the area of the second end (34) of the axial through bore (32) and that of the outlet opening (25) is at least equal to three.

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