阅读说明：本技术 用于热浸镀层设备的风口支管及其运行方法 (Tuyere stock for hot dip coating installation and method for operating same ) 是由 米夏埃尔·彼得斯 斯里德哈·巴莱普 马克·布卢梅瑙 弗洛里安·施佩尔茨 安德列亚斯·韦斯特费 于 2017-06-12 设计创作，主要内容包括：本发明涉及用于扁平产品(11)的热浸镀层设备的风口支管(9),该风口支管从连续炉(10)的出口延伸到镀层浴液面(12)下方的熔体(13)中,并使扁平产品(11)与周围环境隔离,其中设置有至少一个抽吸单元(3)和一个吹入单元(1),并且该至少一个的抽吸单元(3)设置在该至少一个的吹入单元(1)和镀层浴液面(12)之间,其特征在于,在吹入单元(1)和连续炉(10)的出口之间布置有压力补偿单元(7),并且在连续炉(10)的出口处设有第一压力传感器(14.1),在镀层浴液面(12)与压力补偿单元(7)之间设有第二压力传感器(14.2)。(The invention relates to a tuyere stock (9) for a hot dip coating installation for flat products (11), which extends from the outlet of a continuous furnace (10) into the melt (13) below the coating bath level (12) and insulates the flat products (11) from the surroundings, wherein at least suction units (3) and blowing units (1) are provided and the at least suction units (3) are arranged between the at least blowing units (1) and the coating bath level (12), characterized in that a pressure compensation unit (7) is arranged between the blowing units (1) and the outlet of the continuous furnace (10), and in that a pressure sensor (14.1) is arranged at the outlet of the continuous furnace (10), and in that a second pressure sensor (14.2) is arranged between the coating bath level (12) and the pressure compensation unit (7).)

1. Tuyere stock (9) for a hot dip coating installation for flat products (11), which tuyere stock extends from the outlet of a continuous furnace (10) into the melt (13) below the coating bath level (12) and insulates the flat products (11) from the surroundings, wherein at least suction units (3) and at least blowing units (1) are provided and at least suction units (3) are provided between at least blowing units (1) and the coating bath level (12), characterized in that a pressure compensation unit (7) is arranged between the blowing units (1) and the outlet of the continuous furnace (10), and in that a pressure sensor (14.1) is provided at the outlet of the continuous furnace (10), and in that a second pressure sensor (14.2) is provided between the coating bath level (12) and the pressure compensation unit (7).

2. Tuyere stock according to claim 1, characterized in that the suction unit (3) is arranged at a distance of 50mm to 200mm from the coating bath level (12).

3. Tuyere stock according to claim 1 or 2, wherein the distance between the suction unit (3) and the blowing unit (1) is at most 750 mm.

4. Tuyere stock according to any of claims 1 to 3, wherein a dew point unit (15) is provided, through which humidified protective gas can be supplied for dew point adjustment.

5. Tuyere stock according to claim 4, characterized in that said dew point unit (15) is arranged between the coating bath level (12) and the suction unit (3).

6. The tuyere stock of any of claims 1 to 5, wherein at least of said blowing-in units (1) and suction units (3) extend on both sides of the flat product (11) at opposite walls in each case over the transverse extension of the tuyere stock (9), said blowing-in units (1) being arranged directly opposite one another, wherein the blowing-in units (1) each comprise at least two rows of slotted nozzles, each row consisting of a plurality of slotted nozzles (2) and having interruptions between them, wherein the slotted nozzles (2) of the rows are arranged offset from one another, and wherein said interruptions are shorter than the slotted nozzles (2) of the adjacent rows, thereby causing the slotted nozzles (2) of the rows to overlap in the material flow direction (M), and wherein the slotted nozzles (2) of blowing-in units (1) are each interrupted opposite the oppositely situated blowing-in units (1).

7. Method for operating a tuyere stock (9) according to any of claims 1 to 6, characterized in that 100Nm by blowing unit (1)³H to 500Nm³The protective gas is introduced in an amount of blowing/h and 150Nm is sucked in by means of a suction unit (3)³H to 700Nm³A suction quantity/h, and the condition that the suction quantity is greater than the blowing quantity is satisfied, and a compensation quantity is introduced by means of a pressure compensation unit (7) to achieve a pressure decoupling of the continuous furnace (10) and the tuyere stock (9).

8. A method as claimed in claim 7, wherein the suction is at least 50Nm greater than the insufflation volume³The amount pumped in/h.

9. The method according to claim 7 or 8, characterized in that the compensation amount is adjusted on the basis of the difference between the th pressure sensor (14.1) at the outlet of the continuous furnace (10) and the second pressure sensor (14.2) between the coating bath liquid level (12) and the pressure compensation unit (7), and that the difference is kept in the range of more than 0mbar, preferably more than 0.1mbar to 0.7 mbar.

10. method according to any of claims 7 to 9, characterized in that the protective gas is blown onto the flat product (11) at a speed of 4 to 10 m/s.

11. The method of any of , wherein the protective gas is blown at a temperature of 500 ℃ to 650 ℃.

12. The method of any of claims 7-11, wherein nitrogen or a nitrogen-based mixture is used as the shielding gas.

13. Method according to any of claims 7-12, characterized in that hydrogen is mixed into the protective gas in a proportion of 0.5-10% by volume, especially when the threshold value for the oxygen content in the tuyere stock (9) exceeds 10 ppm.

14. method according to any of claims 7-13, characterized in that the dew point in the tuyere stock (9) is set in the range from +30 ℃ to-40 ℃.

15. Method according to any of claims 7-14, characterized in that at least parts of the suction volume are cleaned in a cleaning unit and re-supplied as protective gas into the blowing unit (1), the compensating unit (7) and/or the continuous furnace (10).

Technical Field

The present application describes a so-called "tuyere stock" configuration (english: snout), such as is commonly used in industrial practice as the main equipment part of hot dip or flame plating equipment. Via such tuyere stock, a metallic flat product, such as steel, which has previously been heat treated in a continuous process, is transferred in strip form to a coating bath consisting of a molten metal, such as a Zn-based or Al-based alloy, thereby preventing contact between the heat treated surface and the ambient atmosphere.

Background

In addition, the iron oxide formed in the preheating zone is reduced, in the cooling zone after the continuous annealing furnace, the strip is cooled in a protective gas (HNX) to a temperature close to the bath temperature, the protective gas prevents the strip after annealing from oxidizing before the flame coating, which can greatly impair, for example, the adhesion of the zinc layer, because of the different treatments, different gas atmospheres in the chambers are also required to a certain extent in , and the connections or gates between the annealing furnace and the bath containing the protective gas are referred to as tuyere stock.

For any operator of such a hot dip coating installation, the reason for this constitutes a major challenge with regard to coating defects in the tuyere stock. It is known that metal evaporates from the liquid bath level in the tuyere stock and can deposit, for example, on the steel strip or on the inner wall of the tuyere stock. This phenomenon is enhanced when measures are taken to generate a directed flow in the melt in the tuyere stock, for example by using a zinc pump. Both of which can cause quality defects in the flat steel product to be produced, for example, also as a result of coagulated and agglomerated metal dust falling from the inner wall of the tuyere stock onto the flat steel product.

Simple and established countermeasures are, for example, targeted wetting of the tuyere stock atmosphere to reduce the evaporation rate or heating of the tuyere stock. However, the former has the adverse side effect of increased slag formation on the surface of the molten bath or on the surface of the coating bath, which likewise leads to quality defects. Furthermore, the tuyere stock heating itself cannot prevent the presence of metal dust, so that it may still have an effect of damaging the process.

It has been recognized that the steel strip moving in the direction of the zinc bath carries protective gas downwards in the tuyere stock, wherein the entrained protective gas absorbs zinc vapour on the surface of the zinc bath, which condenses or re-sublimes when the carried protective gas rises to the inner wall of the colder tuyere stock and is deposited there as dust. Therefore, the prior art describes various solutions for preventing or removing metal dust in the tuyere stock.

From JP H07-157853(a) is known devices for removing zinc vapour in the tuyere stock of a continuous strip galvanizing plant, in order to remove the zinc vapour formed on the surface of the zinc bath, the tuyere stock is equipped with blow-in ports (circulation ports) and suction ports arranged vertically below it, in a th embodiment a single blow-in port is arranged in the tuyere stock wall towards the top side of the steel strip and a single suction port is arranged vertically below it, correspondingly a single blow-in port is also arranged in the tuyere stock wall towards the bottom side and a single suction port is arranged vertically below it, in a second embodiment a single blow-in port is arranged in the side wall of the tuyere stock and two suction ports are arranged vertically below it, said suction ports being formed as longitudinal slots in the tube, which pass through the side wall of the tuyere stock and extend over the entire steel strip width at the top side and bottom side thereof, however, this embodiment has the disadvantage of insufficient sealing of the gas atmosphere with and without zinc dust in the tube, from the industry, it is considered disadvantageous that the gas atmosphere between the tuyere stock and the furnace atmosphere of the furnace is too weakly evacuated as a result of dust-increasing the furnace atmosphere, or the furnace atmosphere, which dust is sucked through the tuyere stock.

Another example in the field of tuyere stock for galvanizing installations is known from DE 102012106106 a1, where a region with a plurality of blowing openings is adjacent to a region with a plurality of suction openings, where these regions engage with one another at least partially in a comb-like manner, whereby a relatively good sealing of the rising zinc vapour with respect to the gas atmosphere above it is achieved.

Disclosure of Invention

It is therefore an object of the present invention to provide devices and methods which effectively prevent the influence of adjacent gas atmospheres, in particular to achieve a separation of the tuyere stock and the furnace atmosphere, to prevent unnecessary consumption of protective gas or contamination of the furnace, and to effectively prevent quality defects due to metal dust formed by evaporation from the plating bath.

This object is achieved by a device according to the features of claim 1, in particular if the device is used according to a method corresponding to the features of claim 7.

The invention relates to tuyere stock for a hot dip coating installation for flat products, which extends from the outlet of a continuous furnace up to the melt below the coating bath level and insulates the flat products from the surroundings, wherein at least suction units and blowing units are provided and the at least suction units are arranged between the at least blowing units and the coating bath level, characterized in that a pressure compensation unit is arranged between the blowing units and the outlet of the continuous furnace and that an pressure sensor is arranged at the outlet of the continuous furnace and that a pressure sensor is arranged at the outlet of the continuous furnace

And a second pressure sensor is arranged between the liquid level of the coating bath and the pressure compensation unit. Protective gas, ideally N for cost reasons₂Or alternatively N₂And H₂From blowing unit at least

Blowing the molten steel into the tuyere stock at a temperature of 500 ℃ to 650 ℃ or less, and then drawing the molten steel out again by the suction unit, thereby forming directional airflows on both sides of the steel strip to be produced at the lower portion of the tuyere stock. The directed gas flow describes a vortex from the blowing unit to the strip-shaped product, moving the strip in the direction of the surface of the coating bath corresponding to the direction of flow of the material, via the coating bath to the suction unit. In this way, a good sealing of the vapor rising from the melt is achieved and it is effectively sucked away. In addition, the pressure monitoring is carried out on the tuyere stock atmosphere and the furnace area close to the transition area of the tuyere stock, so that the amount of gas blown into the tuyere stock and sucked out of the tuyere stock can be controlled, and the difference between the pressure of the tuyere stock atmosphere and the pressure of the furnace atmosphere is never less than 0 mbar.

In order to achieve this pressure decoupling, additional protective gas is blown into the tuyere stock at the pressure compensation unit, wherein the amount of protective gas to be blown in here is adjusted such that no negative pressure relative to the furnace occurs in the tuyere stock. Pressure compensation units of the same or similar form as the blowing units are preferably arranged on both sides of the flat product.

An embodiment of the tuyere stock according to the invention is characterized in that the suction unit is arranged at a distance of 50mm to 200mm from the coating bath level. Like the blowing-in unit, the suction unit for removing the tuyere stock atmosphere contaminated with metal dust is positioned transversely to the strip direction and functions at least over the maximum width of the flat product to be produced. The suction unit is here screwed below the lower blowing nozzle and above the surface of the coating bath. The distance to the coating bath is at least 50mm, since below this distance there is a risk of premature failure, and at most 200mm, since otherwise the efficiency of the suction would fall to an insufficient range, since there is insufficient gas flow to form the desired gas vortex or circulation.

Furthermore, an embodiment of the tuyere stock according to the invention is characterized in that the blowing-in unit is arranged at a distance of 200mm to 800mm from the coating bath surface, or more specifically, the distance between the suction unit and the blowing-in unit is at most 750 mm. The minimum distance necessary between the blowing unit and the suction unit is given only by its structural design. However, the maximum distance is 750mm, because if the distance is exceeded, the resulting vortex air flow becomes poor, and only an insufficient effect is obtained.

In a further embodiment, the tuyere stock according to the invention is characterized in that a dew point unit is provided, by means of which humidified protective gas can be supplied for dew point adjustment. Monitoring oxygen (O) in the tuyere stock atmosphere by using corresponding sensors₂) Content and hydrogen (H)₂) Content, the dew point can be monitored and adjusted by means of, for example, a humidified protective gas supply. In addition, humidity reduces the rate of evaporation from the plating bath.

A preferred embodiment of the tuyere stock is characterized in that the dew point unit is arranged between the coating bath level and the suction unit. The added humidity contributes to agglomeration of the metal dust particles, thereby improving the result of the suction. The addition at this location is most efficient.

In a further embodiment, the tuyere stock according to the invention is characterized in that at least blowing-in units and suction units extend on both sides of the flat product in the transverse extension of the tuyere stock at opposite walls, respectively, the blowing-in units being arranged directly opposite one another, wherein the blowing-in units each comprise at least two rows of slit nozzles, each row consisting of a plurality of slit nozzles, and having interruptions between the respective slit nozzles, wherein the rows of slit nozzles are arranged offset from one another, and wherein the interruptions are shorter than the slit nozzles of the adjacent rows, so that the slit nozzles of the rows overlap in the material flow direction, and wherein the slit nozzles of blowing-in units are arranged opposite the respective interruption of the oppositely disposed blowing-in units, so that the blowing-in units are located on the flat product guided through the tuyere stock, preferably on both sides of a continuous material web, for example a dense steel strip, by the arrangement of the rows and the interruption of the rows, it is possible to make optimum use of the slit nozzles, because the jets of the protective gas flows coming out of the adjacent slit nozzles do not interfere with one another and the gas curtain arrangement does not form a closed air curtain in the central region of the closed air curtain, even if the closed air curtain is arranged in the region , the closed air curtain.

Other embodiments of the tuyere stock according to the invention are characterized in that the suction unit comprises main openings arranged in a transversal extension, wherein the main openings are directed in the material flow direction for generating a circulating gas flow, whereby the main openings are located on the side facing away from the blowing-in unit, whereby entrainment of the blown-in gas in the material flow direction is promoted and a turning over of the gas atmosphere is achieved, whereby, for example, also zinc powder in the tuyere stock can be sucked up and subsequently filtered for obtaining a substantially "clean" gas atmosphere.

In a preferred embodiment of the tuyere stock, the blowing-in unit and the suction unit are connected with at least central lines, respectively, for supply and withdrawal of gas, whereby the flow conditions can be kept substantially uniform over the entire width of the blowing-in and suction units.

In a particularly preferred embodiment of the tuyere stock, the main opening has a relatively large height in the region of the central line. By this design, the flow conditions are maintained more uniform across the width, thereby improving the pumping action.

A further embodiment of the tuyere stock is characterized in that the suction unit comprises an additional opening which is oriented perpendicularly to the material flow direction. These additional openings improve the pressure conditions in the tuyere stock and reduce the flow rate at the opening of the suction unit, which has advantages in terms of noise generation and wear.

In an embodiment of the tuyere stock, the slot nozzles are characterized in that the width of the slot nozzles is b, the distance a between the rows is in the range of b ≦ a ≦ 2 × b, and the overlap u of the slot nozzles in the material flow direction is in the range of b ≦ u ≦ 3 × b, with the addition of a ≦ u. The distance of the slot nozzles from one another must not be too great in order to achieve optimum gas-atmosphere separation. It has been found here that the minimum distance between the rows is of equal width to the width of the slot nozzle, which achieves good results and in the case of distances greater than twice the width the risk of separation deterioration increases.

A preferred embodiment of the tuyere stock is characterized in that the slotted nozzle has a length l in the transverse direction, wherein the length l is in the range of 20 & ltb & lt/l & ltb & gt, 50 & ltb & gt, preferably in the range of 30 & ltb & lt/l & ltb & gt, 35 & ltb & gt.

By dividing into individual sections of preferably equal width, step improves the flow conditions over the entire width of the tuyere stock and additionally reduces the power required per line.

An embodiment of the tuyere stock is characterized in that the blowing-in unit and/or the suction unit has a semicircular cross section. The rounded cross section has a geometry which is advantageous in terms of flow technology. Furthermore, by means of the blowing or suction unit mounted on the wall of the tuyere stock, the cross-section of the tuyere stock to be sealed is reduced.

The tuyere stock according to the invention is preferably operated by methods which are characterized by 100Nm by the blowing-in unit³H to 500Nm³/h(Nm³Standard cubic meters per hour) and 150Nm is sucked in by means of a suction unit³H to 700Nm³A suction quantity/h, and the condition that the suction quantity is greater than the blowing quantity is satisfied, and a compensation quantity is introduced by means of a pressure compensation unit to achieve pressure decoupling of the continuous furnace and the tuyere stock. For the formation of a dense gas curtain, a possible introduction of 100Nm has proven to be feasible³H to 500Nm³Because below the lower limit an adequate seal cannot be achieved and above the upper limit turbulence increases, which deteriorates the effectiveness and may lead to strip oscillations.

The method according to the invention is characterized in that the suction is at least 50Nm greater than the insufflation volume³The amount pumped was/h. This ensures that a stable vortex is formed in the lower region of the tuyere stock and that the formed metal dust is reliably sucked.

The method according to an embodiment of the invention is characterized in that the compensation quantity is adjusted on the basis of the difference between the th pressure sensor at the outlet of the continuous furnace and the second pressure sensor between the coating bath liquid level and the pressure compensation unit, and that the difference is kept at more than 0mbar, preferably more than 0.1mbar, to 0.7 mbar.

An embodiment of the method according to the invention is characterized in that the protective gas is blown onto the flat product at a speed of 4m/s to 10 m/s. The most advantageous arrangement for removing metal dust from the tuyere stock atmosphere and thus preventing quality defects is obtained if the protective gas to be blown into the tuyere stock through the blowing unit is blown directly onto the steel strip at a speed of 4m/s or more and 10m/s or less. If this threshold is lower or exceeded, this measure will be ineffective, because, for example, no sufficient gas vortex can be established, or the atmosphere becomes too turbulent.

An embodiment of the method according to the invention is characterized in that a protective gas is blown in at a temperature of 500 ℃ to 650 ℃. In this way, the flat product is placed or maintained at the strip immersion temperature, in order not to disrupt the temperature control or heat treatment of the material and to prevent the condensation of the constituents of the tuyere stock atmosphere.

The method according to the invention is furthermore characterized in that nitrogen or a nitrogen-based mixture is used as protective gas. As a neutral shielding gas, nitrogen has cost advantages.

An embodiment of the method according to the invention is characterized in that hydrogen is mixed into the protective gas in a proportion of 0.5 to 10% by volume. This measure is provided in particular when the threshold value for the oxygen content in the tuyere stock exceeds 10 ppm. If oxygen (O) in the tuyere stock₂) If the concentration exceeds > 10ppm, hydrogen (H) can be selectively added to the reaction mixture₂) (e.g., by a blowing unit). Otherwise, there is a risk of impaired product quality or poor adhesion of the zinc to the steel strip to be produced, due to the non-wetted locations. In supply H₂In the case of (1), H₂The proportion is ideally from 0.5% by volume to 10.0% by volume or less, to ensure effective results, but avoid unnecessary costs.

The method according to an embodiment of the invention is characterized in that the dew point in the tuyere stock is set in the range from-10 ℃ to-40 ℃. It has proven advantageous for the product quality to set the dew point in the tuyere stock to ≦ -10 ℃ to ≥ 40 ℃ depending on the steel alloy to be produced, this being possible by a regulated supply of humidified protective gas (e.g.N)₂) The process is carried out. In this case, the solution according to the inventionThe solution provides that the humidified protective gas is fed directly above the liquid level of the coating bath and below the suction device. The added humidity contributes to agglomeration of the metal dust particles, thereby improving the result of the suction. In addition, humidity reduces the rate of evaporation from the plating bath.

A further embodiment of the method according to the invention is characterized in that at least parts of the suction quantity are cleaned in a cleaning unit and re-fed as protective gas to a blowing-in unit, a compensation unit and/or a continuous furnace, it is provided for increasing environmental compatibility and (cost) efficiency that metal dust in the tuyere stock atmosphere sucked in and contaminated by metal dust is removed and re-fed into the protective gas blowing-in according to the invention₂The concentration, may need to be diluted to meet applicable work safety and explosion protection requirements.

The heating of the tuyere stock or at least the design of the insulation, in order to minimize the deposition of metal dust on the inner wall of the tuyere stock, corresponds to the prior art and is considered self-evident.

Drawings

The invention is explained in more detail below on the basis of schematic drawings, in which parts of the same type are denoted by the same reference numerals. The figures show in detail:

FIG. 1: according to the tuyere stock of the exemplary embodiment of the present invention,

FIG. 2: an exemplary blowing unit viewed perpendicular to the direction of flow of the material, an

FIG. 3: exemplary embodiment of the suction unit.

Detailed Description

Fig. 1 shows a schematic side view of an embodiment of the tuyere stock (9) extends from the outlet of the continuous furnace (10) up to the melt (13) of the coating bath.

In order to prevent additional sealing of the flat products (11) heated in the continuous furnace (10) from the surroundings, the tuyere stock (9) extends straight below the coating bath level (12), a blowing unit (1) is provided in the lower region of the tuyere stock (9), and a suction unit (3) is arranged downstream of the material flow direction (M) and thus between the blowing unit (1) and the coating bath level (12), the blowing unit (1) and the suction unit (3) are arranged laterally on both sides of the flat products (11) over the width of the tuyere stock (9) and opposite one another, respectively, a protective gas of a defined blowing quantity is introduced into the tuyere stock (9) by the blowing unit (1), and a suction quantity greater than the blowing quantity is sucked off by the suction unit (3), a suction gas curtain is formed, the flat products (11) are sucked away through the tuyere stock (11), the remaining tuyere stock (11) is circulated through the tuyere stock (11), and the suction gas curtain is circulated through the tuyere stock (11) and the flat products (11) are sucked away from the tuyere stock (11), the tuyere stock (11).

In order to achieve a pressure decoupling with respect to the continuous furnace (10) in order not to suck the furnace atmosphere into the tuyere stock (9), a pressure compensation unit (7) is provided in the upper end region of the tuyere stock (9) or at the outlet of the continuous furnace (10). The pressure compensation unit (7) is also preferably arranged on both sides of the flat product (11) in such a way as to extend over the width of the tuyere stock (9). Furthermore, in a preferred embodiment, the construction is similar or identical to that of the blowing unit (1). By means of the pressure compensation unit (7), a compensating amount of protective gas is introduced into the tuyere stock (9) in order to compensate for the difference between the blown-in amount and the sucked-out amount.

For adjusting the compensation quantity, at least second pressure sensors (14.1, 14.2) are provided in the tuyere stock, and second pressure sensors (14.1, 14.2) are provided here in the upper region between the pressure compensation unit (7) and the outlet of the continuous furnace (10) in order to detect the pressure in said region, it is of course also possible for the -th pressure sensor (14.1) not to be provided in the tuyere stock (9) but in the outlet region of the continuous furnace (10) or to be formed by a possibly present sensor of the continuous furnace (10). the second pressure sensor (14.2) is arranged downstream of the pressure compensation unit (7) in the material flow direction (M) in order to detect the pressure in the tuyere stock (9). in the preferred embodiment shown, for detecting the difference as good as possible, the second pressure sensor (14.2) is arranged downstream of the blowing-in unit (1). however, the second pressure sensor (14.2) is arranged in the tuyere stock (14) in the furnace manifold (14.1) in order to detect the difference between the atmosphere, but in the furnace atmosphere, and the atmosphere, which the difference between the pressure of the tuyere stock (14.1) is measured by the second pressure sensor (14.2) is not limited to the pressure compensation unit (14.1) by the average value, or by the difference between the pressure of the furnace pressure compensation unit (14.1) is less than 0, which is possible, which is determined by the pressure compensation, which is possible pressure compensation is possible, or even if the pressure compensation is not limited to be adjusted by the pressure compensation unit (14.1) in the pressure compensation unit, which is not limited to be adjusted by the difference between the pressure compensation unit (14.1) in the pressure compensation unit, or even if the difference between the furnace (14, which is not limited to be adjusted by the pressure compensation unit.

In fig. 1 dew point units (15) are also provided, in an embodiment according to the invention or more dew point units (15) can be provided to match the dew point of the atmosphere in the tuyere stock (9) in order to adjust the dew point, a humidified protective gas can be introduced into the tuyere stock in principle at least arbitrary positions of the tuyere stock (9) can be carried out, wherein, as shown in the figure, the dew point units (15) are preferably arranged in the lower region between the suction unit (3) and the coating bath level (12), whereby the evaporation rate from the melt (13) is reduced and at the same time agglomeration of the metal vapour particles is favoured in the tuyere stock atmosphere, thus improving the suction of said particles, wetting of the protective gas supplied to the blowing unit (1) and/or the pressure compensation unit (7) can also be carried out as an alternative to a separate dew point unit (15).

Not shown in fig. 1 are lines (6) for supplying and leading off protective gas to the respective blowing unit (1), suction unit (3), pressure compensation unit (7) and possibly dew point unit (15).

Fig. 2 shows a schematic view of a blowing unit (1) according to the invention, viewed perpendicularly to the material flow direction M, more particularly to the plane of the flat product (11) conveyed through, here two rows of slot nozzles (2) are shown, each having a break or a spacing between the slot nozzles (2), here the slot nozzles (2) each having a width b and a length l, the two rows of slot nozzles (2) being spaced apart from one another in the material flow direction M by a distance a, the slot nozzles (2) of adjacent rows being offset relative to one another such that the breaks of the rows correspond to the slot nozzles (2) of adjacent rows, the slot nozzles (2) being formed longer than the breaks located therebetween, so that, viewed in the material flow direction M, the ends of the slot nozzles (2) have an overlap u, the overlap u being identical along the blowing unit (1).

Fig. 3 shows a partial region which shows the lower blowing unit (1) and the suction unit (3) and parts of the upper blowing unit (1) and the suction unit (3) of the tuyere stock (9) of embodiments, two opposing blowing units (1) at the top wall and the bottom wall of the tuyere stock (9) and a suction unit (3) which is located behind, i.e. downstream in the material flow direction M, it being possible to see in this illustration that the slit nozzles (2) of the blowing units (1) are arranged offset with respect to one another, in addition to the offset between the rows at blowing units (1) which has been shown in fig. 2, fig. 3 also shows the offset of the slit nozzles (2) with respect to the opposing blowing units (1), in the example shown, in the lower blowing unit (1), the outermost slit nozzles (2) seen in the width direction of the tuyere stock (9) are located in front of the slit rows, i.e. upstream rows of blowing units (1) are located behind, and the protective gas flows are largely prevented from reaching the outermost blowing units (3) by the opposing blowing units (3) and the lower blowing units (3) are arranged in front, and the opposing slit nozzles (3) are arranged in the lower blowing units (3) and the protective gas flow direction of the lower blowing unit (3) is very well.

In the example shown in fig. 3, both the suction unit (3) and the blowing unit (1) are divided into a plurality of regions by the intermediate wall (8) as viewed from the width direction. In order to draw off and supply the protective gas to the suction unit (3) and the blowing unit (1), respectively, they have a line (6), which is represented in fig. 3 by a circular connection opening of the line (6). Furthermore, in the example shown, the blowing unit (1) and the suction unit (3) are each formed with a semicircular cross section, which has flow-technical advantages as sharp edges are avoided.

Fig. 3 also shows a preferred embodiment of the suction unit (3). The main opening (4) is oriented in the material flow direction M in order to generate a circulating air flow after the blowing unit (1). The main opening (4) in the region of the line (6) is formed here with a greater height in order to achieve a relatively uniform flow situation over the entire width. Here, the height of the main opening (4) may vary in a continuous manner or, as in the example shown, in a stepwise manner. An additional opening (5) is preferably provided on the top side of the suction unit (3). The additional opening not only improves the suction but also shortens the area of the circulating air flow, which reduces the installation space required in the tuyere stock (9) and promotes the circulating air flow. The additional openings can be formed with the same height over the entire width of the suction unit or with a different height similar to the main opening (4). In the embodiment of the tuyere stock of the flame plating apparatus, the radii of the blowing-in unit (1) and the suction unit (3) may be formed to 40mm, for example, the height of the main opening (4) may be in the range of 10 to 15mm, for example, and the height of the additional opening (5) may be about 8 mm. In the present example, the line (6) may then be formed with a diameter of about 60 mm.

The various features of the invention can be combined with one another in any desired manner and are not limited to the embodiment examples described and illustrated.

Description of the reference numerals

1 blowing unit

2-gap nozzle

3 suction unit

4 main opening

5 additional opening

6 pipeline

7 pressure compensation unit

8 intermediate wall

9 tuyere branch pipe

10 continuous furnace

11 Flat product

12 coating bath surface

13 melt

14.1 th pressure sensor

14.2 second pressure sensor

15 dew point unit

a distance

b width of

length l

u overlap

M material flow direction