Title of Invention

A WIPING DEVICE WITH A GAS JET AND A WIPING PROCESS

Abstract

. A wiping device with a gas jet, designed for controlling the thickness of a liquid metal coating (1) formed on a metal filament (2) . leaving a bath (3) of this liquid' metal and moving substantially vertically above this bath, this device being designed to be fitted up at a certain distance above this bath (3), and comprising an element (5) showing a cylindrical tubular space (6), in which the filament (2) can move substantially axially, an injector (7) at the tubular space (6) being provided, allowing to direct towards the filament a gas current, for example nitrogen, said element (5) being designed to wip the excess of liquid metal carried along by the filament (2) from the above said bath (3), characterised in that said injector (7) is annular and coaxial with respect ,to the fiJament and directs towards the filament said gas current in the form of a knife perpendicularly to the axis of said filament and oriented radially with, respect to the latter within said cylindrical tubular space (6) which is open at its two extremities, in that the above said element (5) is fitted in a removable way to allow the replacement of an element having a given internal diameter by another element, according to the diameter of the filament to be treated, and in that the aforesaid element comprises at least two blocks (5a) and (5b), preferably prismatic, which can be moved with respect to each other between, on the one hand, a closed or working, position, in which the blocks (5a) and (5b) are applied against each other 'wvhile delimiting between them said cylindrical tubular space (6), in which the said filament (2) can move substantially axially and, on the other hand, a spread or open position allowing to laterally access the above said space (6), in particular for the positioning of the filament (2) in the device.

Full Text

This invention is related to a wiping device with a gas jet, and a wiping process designed to control the thickness of a liquid metal coating formed on a metal filament leaving a bath of this liquid metal and moving substantially vertically above this bath, this device being designed to be fitted up at a certain distance above this Bali, and comprising an element showing a tubular space with a circular cross section, in which the filament can move substantially axially, a coaxial annular injector at the tubular space being provided, allowing to direct towards the filament a gas current for example nitrogen, in the form of a knife perpendicularly to the axis of said filament and oriented radially with respect to the latter, so as to allow to wipe the excess of liquid metal carried along by the filament Several devices of the above mentioned type have already been developed with widely varying success. The basic principle is to push back the metal fluid by means of a gas knife, which is generally formed by nitrogen. The known devices show the inconvenience of occasioning a nitrogen pressure profiled which is not uniform on the whole circumference of the wire. Due to this, as soon as the wire reaches a certain speed irregularities are caused in the coating formed on the filament. Moreover, for each diameter of filament, in the devices known in particular for limiting or controlling the gas consumption, an element with a different tubular space must be provided. This thus requires, replacement of an element by another appropriate element, often requiring a disassembling of the whole of the device, and consequently a precious time of production which cannot be disregarded, as well as delicate adjusting of alignment with the filament when putting into operation a new element with a tubular space. One of the essential aims of this Invention is to remedy the inconveniences of the known devices, in particular a quick exchange of the element without having to get down to a realignment, and moreover, to allow to combine an increase of the line speed of de filaments with a decrease of the thickness of the coating, in order to approach as much as possible the minimum determined by the standards, which for example in the case of ACSR wires is the ASTM B498 standard, and this while maintaining a coating of very good quality and as uniform as possible, and this with a minimal gas consumption. For that purpose, according to the invention, the above said element is fitted into the device in a removable way, so as to allow the replacement of an element by another element, according to the diameter of the filament to be treated. Advantageously, the aforesaid element comprises at least two blocks, preferably prismatic, which can be moved with respect to each other between, on the one end, a closed or working position in which the blocks are applied against each other, delimiting between them a tubular space, which is open at both its extremities, and in which said filament can move substantially axially, and in the side wall of which is made a slot determining the aforesaid coaxial annular injector, and, on the other hand, a spread or open position allowing to access the above said space laterally, in particular for the positioning of the filament in the device. The invention also concerns a particular wiping process for the control of the thickness of a liquid metal coating formed on a filament leaving a bath of this liquid metal and moving vertically above this bath, by creating around the filament a gas current in the form of a knive perpendicularly to the axis of said filament and directed radially towards the latter, so as to allow to wipe the excess of liquid metal carried along by the filament firom the above said bath, in particular by using the device as defined above. This process is characterized in that the thickness of this coating is adjusted by varying, for an element showing a tubular space with a circular cross section in which said filament moves axially, the pressure of the wiping gas (Png) at the outlet of the annular injector, according to the diameter of the filament to be treated, according to the formula as defined in claim 15. A process is concemed which allows, according to the diameter of the filament, the line speed of the latter and the thickness of the coating, to determine the gas pressure at the inlet of the used wiping device. Accordingly, the present invention provides a wiping device with a gas jet, designed for controlling the thickness of a liquid metal coating formed on a metal filament leaving a bath of this liquid metal and moving substantially vertically above this bath, this device being designed to be fitted up at a certain distance above this bath, and comprising an element showing a cylindrical tubular space, in which the filament can move substantially axially, an injector at the tubular space being provided, allowing to direct towards the filament a gas current, for example nitrogen, said element being designed to wipe the excess of Uquid metal carried along by the filament from the above said bath, characterised in that said injector is annular and coaxial with respect to the filament and directs towards the filament said gas current in the form of a knife perpendicularly to the axis of said filament and oriented is radially with respect to the latter within said cylindrical tubular space which is open at its two extremities, in that the above said element is fitted in a removable way to allow the ■eplacement of an element having a given internal diameter by another element, according to the diameter of the filament to be treated, and in that the aforesaid element comprises at least two blocks and, preferably prismatic, which can be moved with respect to each other between, on the one hand, a closed or working, position, in which the blocks and are apphed against each other while delimiting between them said cylindrical tubular space, in which the said filament can move substantially axially and, on the other hand, a spread or open position allowing to laterally access the above said space, in particular for the positioning of the filament in the device. Accordingly the present invention also provides a wiping process with a gas jet designed to control the thickness of a liquid metal coating formed on a filament leaving a bath of this liquid metal and moving vertically above this bath, by creating around the filament, from an annular injector, a gas current in the form of a knife perpendicularly to the axis of the said filament and directed radially to the latter, so as to allow to wipe the excess of hquid metal carried along by the filament from the above said bath, in particular by using the device as described above, characterised in that the thickness (Cpf) of this coating is adjusted, by varying, for a given element, showing a tubular space with a circular cross section in which the said filament is moving axially, the pressure of the wiping gas (Pna) at the outlet of the annular injector according to the diameter (d) of the filament to be covered, according to the formula^ ^ — i in which: -Cpf = the thickness of the coating of the filament (2) after wiping, measured in metres, J -f 2E. -R = —2— in which E represents the thickness of possible alloy formed on the fihn, calculated in metres, -U = the speed of the filament (2) in m/sec, hkk -H = R + kk, in which kk = xpixio^ and hkk ^ the initial thickness of the liquid metal layer on the wire before wiping, and complies with the formula ?^ iO X Nj- in which ul = viscosity in Pa.sec of the liquid metal carried along at the considered temperature; p\ = the voluminal mass of the metal in kg/ni3 carried along at the considered temperature; g = acceleration, in m/sec^, due to gravity; Kf = a coefficient, depending on the state of the wire, and determined experimentally; - P = a coefficient calculated on the basis of the formula P=- -^ ^ O^OS (b) id in which P^a is the pressure at the outlet of the tubular injector, S is the thickness of the gas knife at this outlet, and 2 con^lies with the following formula: in which D is the diameter of the tubular space, - C = a shearing coefficient complying with the formula: ^ „ f 1 0.00664 xZ"" X P„,"-""" H Other details and characteristics of the invention will appear from the description given below as a non limiting example, of two particular embodiments of the wiping device according to the invention, and of a particular embodiment of the process for the control of the thickness of the coating formed on a filament to be covered, with reference to the attached drawings. Figure 1 is a schematic side view of a filament covered by a liquid metal film, submitted to a wiping by a gas knife in compliance with a process according to the invention. Figure 2 is a view in perspective of a first embodiment of the device according to the invention, in its open position. Figure 3 is an exploded view in perspective of this first embodiment. Figure 4 is a schematic view of a vertical section of an essential part of a second embodiment of the device according to the invention. Figure 5 is an exploded view in perspective of two important fragments of this essential part of this second embodiment. In the different figures, the same reference numbers concern identical or analogous elements. As is schematically shown by figure 1, this invention concerns a wiping device and process designed to control the thickness of a liquid metal coating 1, such as zinc, on a filament 2, such as a steel wire with circular section, leaving a bath 3 of this liquid metal according to an substantially vertical direction. The wiping of the excess liquid metal carried along by the wire 2 from the bath 3 is carried out by means of a knife of gas under pressure, such as nitrogen, directed radially and perpendicularly to the surface of the wire 2, as indicated by the arrow 4 in figure 1. The device according to the invention, is designed to be fitted above this bath 3 and comprises an element 5, preferably constituted of two identical paralleiepipedal blocks 5a and 5b, which when put against each other, may delimit a tubular space 6, showing a circular section perpendicularly to its axis, in which the wire 2 to be covered by the coating 1 can move substantially axially. The aforesaid gas knife is created by a coaxial annular injector 7 at the tubular space 6. This injector is formed by an annular slot 7, parallel to a plane which is perpendicular to the axis of the tubular space 6 and of constant dimensions on the whole circumference of the latter. As is shown in more detail in figures 2 and 3, in the first embodiment of the device according to the invention, the element 5 according to the invention, is fitted in a removable way on the wiping device to allow to replace an element with a given internal diameter by another element, according to the diameter of the wire 2 to be treated, and this without having to disassemble the whole of the wiping device, and thus to get down to a realignment. In this way, advantageously, the two aforesaid distinct prismatic blocks 5a and 5b can be moved with respect to each other between, on the one hand, a closed or working position, and, on the other hand, an open or spread position. In the closed position, the blocks 5a and 5b are applied against each other and delimit between them a tubular space 6 with a circular section open at its two extremities, in which the wire 2 can move axially, and in the side wall 9 of which is provided the slot 7 determining the aforesaid coaxial annular injector. In the open position, as is shown in figure 2, the two blocks 5a and 5b are brought at a certain distance from each other, so as to allow to access the tubular space 6 laterally, for example for the positioning of a wire 2 in the wiping device. According to a preferred embodiment of the invention, the two blocks 5a and 5b each show a respective semi-cylindrically shaped recess 6a and 6b, these two recesses forming in the above said closed position the tubular space 6. The block 5a is fixed in a removable way on the fixed support 8a of the wiping device, the other block 5b being fitted facing the block 5a on a mobile support 8b which can undergo a translation with respect to the fixed support 8b between the closed position and the open position, as is shown by the arrows 30 in figure 2. In this respect, in the two particular embodiments shown in figures 2 to 4, the mobile support 8b rests with a sliding motion on two arms 10 fixed on either side of the latter. An eccentric mechanism 11 with a lever 15 cooperates with the arms 10 at the side of the mobile support 8b opposed to that directed towards the fixed support 8a. This mechanism 11 comprises a cylinder 12 which is rotatable around an axis 12a parallel to the axis 12b of the cylinder 12, extending transversely with respect to the arms 10. On either side of the cylinder 12 tail shafts 23 are provided, the axis of which coincides with the axis 12a and which are fitted revolvingly and in a removable way in the corresponding seatings 14 made in the upper edges of the arms 10. A lever 15 is screwed into the side wall of the cylinder 12 and extends perpendicularly to the axis 12a of the tail shafts 23, so as to allow to submit this cylinder to a pivoting around this axis 12a between a locking position in which the block 5a is pressed against the block 5b by the cylinder 12, thanks to the eccentricity between the axis 12b of the latter and the axis 12a, and an unlocking position, in which the axis 12b is located to the opposite side of the axis 12a with respect to the blocks 5a and 5b. in order to allow to release the tail shafts 23 through the access opening 13 of their respective seatings 14, to bring the device in its open position, as is shown in figure 2, a segmental part has been removed from each of these tail shafts 23. In the first embodiment of the device according to the invention, shown in figures 2 and 3, each of the blocks 5a and 5b is constituted of two distinct superposed parts showing the form of a rectangular parallelepiped. These parts 18 and 19 are attached in a removable way to each other and to their respective supports 8a and 8b by means of screws 24 making between these parts 18 and 19 the aforesaid annular slot 7, which is constituted by a recess machined in the form of a semi-circle in the upper side 20 of the part 18 of each block 5a and 5b. This slot 7 communicates with a gas feed chamber 17, also in the form of a semi-circle, hollowed out in the part 19 and extending over the whole height of the latter. This chamber 17 Is connected up with a gas delivery line, not shown, connected above the support 8a, by a ducting 25 crossing the support 8a starting from its upper side 26 and emerging into the chamber 17 of the block 8a. The support 8b contains the same ducting 25, but the function of this one is to allow the measurement of the pressure by a manometer, not shown, connected to this ducting 25 at the site where it emerges in the upper side 26 of this support 8b. Moreover, the ducting 25 of the fixed support 8a Is connected to that of the support 8b, in the closed position of the blocks 5a and 5b, by two pipes 27 formed on either side of the tubular space 22, so as to feed gas to the slot 7 of block 5b. Finally, the wiping device, as It is shown in the figures, comprises an attaching part 29 allowing to fit it by screws 30 onto a positioning device, not shown, which is mobile between determined limits. The second embodiment of the wiping device according to the invention, as it is illustrated in figure 4, is distinguished from the first embodiment by the fact that the blocks 5a and 5b each show a removable internal fitting 28 forming the side wall 9 of the tubular space 6 and thus having the form of a semi-cylinder. This fitting 28 is constituted of two parts 28a and 28b arranged in the prolongation of each other, parallel to the axis of the space 6 and making between each other the aforesaid slot 7. In this embodiment, the blocks 5a and 5b are constituted of a single piece and the feed chamber 17 Is located inside the blocks 5a and 5b facing the slot 7. In this way, in this second embodiment, the blocks 5a and 5b can, if necessary, be integral with and unremovable from the supports 8a and 8b, since only the fittings 28 need to be replaced by fittings with a different internal diameter, according to the diameter of the wire 2 to be covered with a metal coating. On the other hand, in the second embodiment, the blocks 5a and 5b themselves have to be replaced, which in general however, is an easier and quicker operation than the replacement of the fittings 28. Besides, in each of these embodiments, a cylindrical buffer chamber 16, coaxial to the tubular space 6, extends below the latter and emerges above the bath 3 while communicating with the surrounding atmosphere, so as to be able to create around the wire 2 an area slightly in overpressure by the gas originating from the injector 7. This chamber 16 preferably shows a diameter clearly superior to that of the tubular space 6 in order to promote the return to the bath 3 of the excess of liquid metal carried along by the wire 2 and wiped by the gas knife. The invention also concerns a wiping process with a gas knife allowing to control the thickness of a liquid metal coating 1 formed on a wire 2 leaving the bath 3 of this liquid metal and moving vertically above this bath 3. This thickness depends on a whole series of parameters. According to the invention, a relationship has been established between these different parameters, allowing for a given wiping device, to adjust the pressure (Pna) of the wiping gas at the outlet of the slot according to the diameter (d) of the wire to be covered, moving at a given vertical speed U facing the wiping gas knife. This relationship is established as follows: 2 (TJ n r 1^1 TT2 r /rrs ^^^ Cpf = jR"+jjx \.[u^-je),L^,H^-n^,.,c[^,EL^[,,„if_ \\\\-R J) (a) in which: - Cpf = the thickness of the coating of the filament (2) after wiping, measured in metres, - R = in which E represents the thickness of possible alloy formed on the film, calculated in metres, - U = the speed of the filament (2) in m/sec, - H = R + kk, in which kk = —^^^ , in metres \p\ X 10" and hkk = the initial amount of the liquid metal layer in g/m^ on the wire before wiping, complying with the formula in which ul = viscosity in Pa.sec of the liquid metal carried along at the considered temperature; p1 = the voluminal mass of the metal in kg/m^ carried along at the considered temperature; g = acceleration, in m/sec^, due to gravity; Kf = a coefficient, depending on the state of the wire, and determined experimentally; - P = a coefficient calculated on the basis of the formula 14.12216 xP„^ plxg + ---~7=~ p ^ vyz ^ Q Qg (5, ul in which Pna is the pressure at the outlet of the tubular injector, S is the thickness of the gas knife at this outlet, and Z compiles with the following formula: in which D is the diameter of the tubular space (6), - C = a shearing coefficient complying with the formula; f 1 0.00664 X Z"^"" X P«a"-™ H) C-H.[-. ^, -i^x-J The thickness of the coating can be calculated in g/m^ by means of the formula Cpf x 10^ x p1. When the wire is immerged in a liquid metal capable of creating an alloy layer, the diameter to be considered is that of the wire itself, increased by twice the thickness of the alloy. This is for example the case, when the wire is of iron and the covering metal is formed of zinc. In such a case, an Fe-Zn alloy will form on the wire leaving the bath. In order to allow to determine the pressure by aforesaid manometer, at the inlet of the used wiping device, which must be applied to obtain the desired pressure Pna at the outlet of the injector 7, necessary to form the desired thickness of the metal coating on the wire, repeated tests have to be carried out on this device, so as to be able to determine the loss of pressure between this manometer and the outlet of the injector. Thus, once the relationship between the loss of pressure and the pressure measured by the manometer could be established, the gas pressure can be determined by the manometer to obtain the pressure Pna and, by applying the formula (b) given above, one can calculate the value of the coefficient P to be introduced into the relationship (a) to obtain the desired thickness Cpf of the metal coating on the wire to be treated. The aforesaid relationship (a) is preferably applied for wire diameters, possibly comprising an alloy layer, which may vary from 0.8 to 8 mm. It was confirmed, according to the invention, that when one desires to reduce the gas consumption to a strict minimum, the ratio between the diameter of the wire 2 and that of the tubular space 6, or of the distance between the slot 7 and the wire must be maintained below certain limits. Thus, in practice, one proceeds as follows: Diameter of the wire Diameter of used tubular space 6 0.8 to 1.8 mm 6 mm 1.8to2 mm 8 mm 2.8 to 3.5 mm 10 mm 3.5 to 8 mm 12 mm This implies thus that it is important to be able to easily and quickly replace, without having to get down to a realignment of the device, the parts of the latter determining the diameter of this tubular space. Below is given an example of the application of the aforesaid relationship (a) to a given wiping device for a steel wire with a given diameter (d), moving at a given speed (U), and onto which a zinc coating with a thickness of 350 to 400 g/m must be formed. U S d D In more concrete terms, the known or calculated parameters which have to be taken into account to establish the relationship (a) are as follows: 1.083 m/s 0.0006 m 0.00179 m (including the Zn-Fe alloy layer) 0.006 m p1 7140 kg/m u1 ; 0.0034165 Pa.s pa : 1.1132615 kg/m^ ua : 0.0000165 Pa.s g : 9.81 m/s^ C : -90.6459 H : 0.001052 hkk : 568.10 g/m^ hk : 0.0000796 m. The used device is of the type as shown in figures 2 and 3. If one introduces the aforesaid parameters and a desired thickness Cpf in the relationship (a), one may calculate the coefficient P, which by application of the formula (b) allows to find the pressure Pna and, consequently, the gas pressure to be established by manometer at the inlet of the device. However, another possibility, generally more practical, consists in proceeding by trial and error, by introducing first any value for Pna in the formula (b), allowing to obtain a corresponding Cpf value in the relationship (a) and to reduce or increase the Pna value according to the Cpf value obtained, until obtaining a Cpf value within the limits defined for the thickness of the metal coating of the wire, which in the present case was 350 to 400 g/m^. Thus it was found that by giving Pna a value of 55 mm H2O, the Cpf value was 0.0000531 m, i.e. 379.40 g/m^. It is important to note that the relationship (a) as given above applies not only to the wiping device according to the invention, but to any type of wiping device using a gas knife oriented horizontally to a wire which is moving vertically above a liquid metal bath. It is clear, that the invention is not limited to the embodiments of the wiping device such as shown in the attached figures and to the wiping process described above, but that many alternatives may be considered without abandoning this invention, in particular with respect to the means used to give access to the tubular space 6 in which the wire to cover is moving. Thus, although the invention may be applied for the coating of any type of wire or elongated substrate by any metal or metal alloy, it is advantageously used for the coating of steel wires by a zinc or zinc alloy coating. CLAIM;. 1. A wiping device with a gas jet, designed for controlling the thickness of a liquid metal coating (1) formed on a metal filament (2) leaving a bath (3) of this liquid" metal and moving substantially vertically above this bath, this device being designed to be fitted up at a certain distance above this bath (3), and comprising an element (5) a cylindrical tubular space (6), in which the filament (2) can move substantially axially, an injector (7) at the tubular space (6) being provided, allowing to direct towards the filament a gas current, for example nitrogen, said element (5) being designed to wip the excess of liquid metal earned along by the filament (2) from the above said bath (3), characterised in that said injector (7) is annular and coaxial with respect to the filament and directs towards the filament said gas current in the form of a knife perpendicularly to the axis of said filament and oriented radially with respect to the latter within said cylindrical tubular space (6) which is open at Its two extremities, in that the above said element (5) is fitted in a removable way to allow the replacement of an element having a given internal diameter by another element, according to the diameter of the filament to be treated, and in that the aforesaid element comprises at least two blocks (5a) and {5b), preferably prismatic, which can be moved with respect to each other between, on the one hand, a closed or working, position, in which the blocks (5a) and (5b) are applied against each other while delimiting between them said cylindrical tubular space (6), in which the said filament (2) can move substantially axiaily and, on the other hand, a spread or open position allowing to laterally access the above said space (6), in particular for the positioning of the filament (2) in the device. 2* The device according to claim 1, wherein said cylindrical tubular space (6) has a side wall (9) wherein is made a slot (7) determining the aforesaid coaxial annular injector. 3, The c3evice according to any one of claims 1 or 2, wherein the aforesaid element comprises two distinct blocks (5a) and (5b), each of these blocks showing a semi-cylindrically shaped recess (6a) and (6b), the two recesses forming, in the above said dosed position, the aforesaid tubular space (6). 4, The device according to any one of claims 1 to 3, wherein one of the two blocks (5a) of the aforesaid element (5) is fitted in a removable way on a fixed support (8a}, the other block (5b) being fitted facing the first said block (5a) on a mobile support (8b), which can undergo a translation between a closed position, in which the blocks (5a) and (5b) are applied against each other, and an open position, in which they are at a certain distance of each other, so as to be able to access the aforesaid tubular space (6). 5. The device according to claim 4, wherein the aforesaid mobile support (8b) is arranged on two arms (10a) and (10b) fitted on the fixed support (8a) on either side of the tatter. g^ The device according to claim 5, wherein the mobile support (8b) rests with a sliding motion on the two aforesaid arms (1 Oa) and (1 Ob), an eccentnc mechanism (11) being fitted on these arms (10a) and (10b) at the side of the mobile support (8a), opposed to that directed towards the fixed support (8a), this mechanism (11) comprising a cylinder (12) which can rotate around an eccentric axis parallel to that of the cylinder (12), extending transversely with respect to the arms (10), so as to be able to press the mobile support (8b) in its closed position by the action of the cylinder (12) by bringing together the axis of the latter and the fixed support (8a), and to be able to release this mobile support (8b) by rotating the cylinder (12) around the above said eccentric axis and separating the axis of the cylinder from the support (8a). 7, The device according to any one of claims 1 to 6, wherein a buffer chamber (16) designed to encompass the filament (2) is provided beiow the annular injector (7) and the aforesaid element (5), emerging above the liquid metal bath (3) and communicating with the surrounding atmosphere, so as to be able to create around the filament (2), between this bath (3) and the device, an area slightly in overpressure by the gas originating from the injector. 8. The device according to any one of claims 1 to 7, wherein the aforesaid annular slot (7) communicates with- a feed chamber (17) provided in the aforesaid blocks, whereby the latter can be connected to a delivery of gas under pressure, allowing to create a gas stream in the form of a knife. 9^ The device according to any one of claims 1 to 8, wherein the aforesaid element (5) comprises a removable internal fitting, forming the side wall (9) of the aforesaid tubular space (6) and showing the aforesaid injector (7). 10. The device according to any one of claims 2 to 9, wherein each of the blocks (5a) and (5b) comprises "O/JO distinct superposed parts (18) and (19), which are attached to each other in a removable way, providing between them the aforesaid annular slot (7). 11. The device according to claim 10, wherein the feed chamber (17) is provided in the upper part (19) of the blocks (5a) and (5b), above the annular slot (7), communicating with the latter over substantially its whole circumference. 12. The device according to any one of claims 10 and 11, wherein the annular slot is provided in the upper side (20) of the lower part (18) of the blocks (5a) and (5b). 13. The device according to any one of claims 11 and 12, wherein the feed chamber (17) extends inside the supports (8a) and (8b) up to a delivery of gas under pressure, connecting means (21) being provided in the supports (8a) and (8b), allowing to connect up the feed chambers (17) of the blocks (5a) and (5b) with each other when these blocks are in their closed position. 14. The device according to any one of claims 4 to 13, wherein the blocks (5a) and {5b) being suspended below the supports (8a) and (8b), the semi-cylindrically shaped recesses {6a) and (6b), provided in these blocks,.extend within the supports (8a) and (8b) over the entire height of the latter, so as to delimit in this way, also by the supports (8a) and {8b), in the closed position of the blocks (5a) and (5b), a tubular space (22), coaxial to the tubular space (6) delimited by the blocks (5a) and (5b). 15, A wiping process with a gas jet designed to control the thickness of a liquid metal coating (1) formed on a filament (2) leaving a bath (3) of this liquid metal and moving vertically above this bath (3), by creating around the filament (2), from an annular injector (7), a gas current in the form of a knife perpendicularly to the axis of the said filament and directed radially to the latter, so as to allow to wipe the excess of liquid metal carried along by the filament (2) from the above said bath (3), in particular by using the device according to any one of claims 1 to 14, characterised in that the thickness (Cpf) of this coating (1) is adjusted, by varying, for a given element (5), showing a tubular space (6) with a circular cross section in which the said filament (2) is moving axially, the pressure of the wiping gas (Pna) at the outlet of the annular injector (7) according to the diameter (d) of the filament (2) to be covered, according to the formula: in which; - Cpf = the thickness of the coating of the filament (2) after wiping, measured in metres, d + 2E - R^ in which E represents the thickness of possible alloy formed en the film, calculated in metres, U = the speed of the filament (2) in m/sec, H = R + kk, in which kk = r \p\x 10" and hkk = the initial thickness of the liquid metal layer on the wire before wiping, and complies with the formula in which ul = viscosity in Pa.sec of the liquid metal carried along at the considered temperature; p1 = the voluminal mass of the metal in kg/m^ carried along at the considered temperature; g = acceleration, in m/sec^, due to gravity; Kf = a coefficient, depending on the state of the wire, and determined experimentally; P = a coefficient calculated on the basis of the formula 14.12216 X ?„ pi X g -f - p ^ Jl^ ^ 0.08 (b) ul in which Pna is the pressure at the outlet of the tubular injector, S is the thickness of the gas knife at this outlet, and Z complies with the following formula: D~d in which D is the diameter of the tubular space (6), - C = a shearing coefficient complying with the formula: ( I 0.00664 xZ°"" x/>„/-^^^ //" ^=^^;;;y^ ^^^ -""^T. j_6, The process according to claim 15. wherein a bath (3) of liquid zinc or zinc alloy is used, and steel filaments (2) to be. covered by a zinc or zinc alloy coating (1). 17. A wiping device with a gas jet substantially as herein described with reference to the accompanying drawings. 18. A wiping process substantially as herein described with reference to the accompanying drawings.

Documents:

937-mas-1998 abstract-duplicate.pdf

937-mas-1998 claims-duplicate.pdf

937-mas-1998 claims.pdf

937-mas-1998 correspondence-others.pdf

937-mas-1998 correspondence-po.pdf

937-mas-1998 description(complete)-duplicate.pdf

937-mas-1998 description(complete).pdf

937-mas-1998 drawings.pdf

937-mas-1998 form-1.pdf

937-mas-1998 form-19.pdf

937-mas-1998 form-26.pdf

937-mas-1998 form-4.pdf

937-mas-1998 petition.pdf