WO2018228663A1 - Apparatus and method for separating gas atmospheres - Google Patents

Abstract

The present invention relates to an apparatus for separating gas atmospheres in a lock, the lock having at least one blowing unit (1) and one suction unit (3) on opposite walls along the transverse extension of the lock, wherein the blowing units (1) are provided so as to be directly opposite and the suction units (3) are arranged downstream in the material flow direction (M), characterised in that each blowing unit (1) comprises at least two rows of a plurality of slotted nozzles (2) with interruptions located therebetween, wherein the slotted nozzles (2) of the rows are offset with respect to one another, and wherein the interruptions are shorter than the slotted nozzles (2) of the adjacent row and therefore the slotted nozzles (2) of the rows overlap in the material flow direction (M) and each slotted nozzle (2) of a blowing unit (1) is opposite a corresponding interruption of the opposite blowing unit (1).

Description

 Apparatus and method for separating gas atmospheres Technical Field

In the field of treatment of materials in transit, there are sometimes gas atmospheres that may differ from adjacent gas atmospheres. The difference may be in different gas compositions or in process-related vapors, dusts or particles that can pollute the gas atmosphere or affect the product. Technical Background (Background Art)

For example, a system for continuous hot-dip galvanizing of steel strip consists inter alia of a continuous annealing furnace, a zinc bath (molten bath), a device for adjusting the zinc coating thickness and a subsequent cooling device. In the continuous furnace, the steel strip is continuously annealed, the continuous furnace being divided into several chambers where different treatments are performed. These treatments include, for example, the adjustment of the desired mechanical properties of the base material by recrystallization of the steel. In addition, iron oxides formed in a preheating zone are thereby reduced. In a cooling zone following the continuous annealing furnace, the strip is cooled under protective gas (HNX) to a temperature close to the molten bath temperature. The inert gas is intended to prevent the annealed strip from oxidizing prior to galvanizing, which would significantly degrade the adhesion of the zinc layer. Due to the different treatments, therefore, sometimes different gas atmospheres in the chambers are required. The shielding gas containing connector or lock between annealing furnace and zinc bath is called proboscis.

In a conventional furnace proboscis of a continuous strip galvanizing plant, deposits of zinc dust usually occur which, especially in the case of vibrations occurring in the plant, fall in large pieces onto the zinc bath and / or the steel strip and thus cause surface defects (galvanizing defects). It was recognized that the moving in the direction of the zinc bath steel strip entrained in the trunk shielding gas down, the entrained inert gas on the zinc bath surface absorbs zinc vapor, which condenses or resov- enced when rising the entrained inert gas on the colder inner walls of the trunk and there as dust settles. From JP H07-157853 (A) a device for removing zinc vapor in a trunk of a continuous strip galvanizing plant is known. In order to remove the zinc vapor produced on the zinc bath surface, the trunk is provided with injection openings (circulation openings) and suction openings arranged vertically underneath. In a first exemplary embodiment, a single injection opening is arranged in the trunk wall facing the upper side of the steel strip and a single suction opening is arranged vertically below it. Accordingly, in the underside of the steel strip facing trunk wall also a single injection opening and vertically below a single suction opening are arranged. In a second embodiment, a single injection port is disposed in a side wall of the spout, while vertically thereunder are provided two exhaust ports formed as longitudinal slots in pipes penetrating the side wall of the spout and extending over the entire top and bottom of the steel belt Steel strip width extend. A disadvantage of such designs, however, is an insufficient sealing of the gas atmosphere with and without zinc dust.

From DE 10 2012 106 106 AI another example from the field of the trunk of a galvanizing plant is known. In this case, an area with a plurality of injection openings adjacent to a region with a plurality of suction openings, wherein the areas mesh at least partially in a comb-like manner. As a result, a relatively good sealing of ascending zinc vapors is achieved with respect to the overlying gas atmosphere. However, such a device is relatively expensive to manufacture and is associated with a high space requirement. Due to the high saturation of the gas atmosphere resulting from the sealing before immersion with zinc vapor, the product quality may continue to be impaired.

Summary of Invention

The invention is thus based on the object to provide a device and method which can effectively prevent interference of adjacent gas atmospheres, in particular a return flow. Other objects of the invention are a favorable manufacturability, to allow a small footprint and easy installation. This object is achieved by a device according to the features of claim 1, in particular when it is used by a method according to the features of claim 11. According to the invention, a device for separating gas atmospheres in a lock, which has at least one injection unit and a suction unit over the transverse extent of the lock on opposite walls, wherein the injection units are provided directly opposite each other and the suction units are arranged downstream in the material flow direction, characterized in that the blowing units each comprise at least two rows of a plurality of slit dies with intervening intersections, the slit dies of the rows being offset from one another and the breaks being shorter than the slit dies of the adjacent row to overlap the slit dies of the rows in the material flow direction, and the slot nozzles of one injection unit are each opposite to an interruption of the opposite injection unit. Thus, the injection units are located on both sides of the material guided through the lock, preferably a continuous material web, such as steel strip, wherein the invention is also applicable to conveyed piece goods. The arrangement in rows and the interruptions in the rows slot machines can be used optimally, since the occurring beam expansion of emerging from adjacent slot nozzles gas streams do not interfere with each other and forms a closed curtain of gas through the arrangement. Due to the likewise staggered arrangement of the slot nozzles of a blow-in unit with respect to the slot nozzles or interruptions of the opposite injection unit, a dense gas curtain is also formed in the center region of the lock, where the injected gas flows meet one another. As a result, a very good separation of the gas atmospheres is also achieved outside the material web or between the cargo.

Further embodiments of the device according to the invention are characterized in that the suction units have main openings provided over the transverse extent, wherein the main openings are aligned in the material flow direction in order to produce a circulating flow. Thus, the main openings are located on the side facing away from the injection unit, whereby a entrainment of the injected gas is favored in the material flow direction and a circulation of the gas atmosphere takes place. In this way, for example, zinc dust in a trunk can be sucked off and then filtered to obtain a largely "clean" gas atmosphere. In preferred embodiments of the device, the injection units and suction units are each connected to at least one centered line for supplying or discharging gas. As a result, the flow conditions over the width of the injection and suction units can be kept largely the same.

In particularly preferred embodiments of the device, the main openings in the region of the centered line have a greater height. By such a design, the flow conditions over the width are kept uniform, which improves the suction effect.

Further embodiments of the device are characterized in that the suction units comprise additional openings which are aligned perpendicular to the material flow direction. These additional openings improve the pressure conditions in the lock and reduce the flow velocities at the openings of the suction unit, which has advantages in terms of noise development and wear.

In embodiments of the device, the slot nozzles are characterized in that the slot nozzles have a width b, that the distance a between the rows is in the range of b <a <2 * b, and that the overlap u of the slot nozzles in the material flow direction in the range of b <u <3 * b, where additionally a <u. In order to achieve the best possible separation of the gas atmospheres, the slot nozzles must not be too far away from each other. Here it has been shown that based on the width of the slot nozzles, a minimum distance between the rows of equal width achieved good results and at a distance of more than twice the width, divides the gas flow and increases the risk of deterioration in separation.

Preferred embodiments of the device are characterized in that the slot nozzles have a length I in the transverse direction, wherein the length I is in the range of 20 * b <I <50 * b, preferably in the range of 30 * b <I <35 * b ,

Devices according to the invention are characterized in further embodiments in that additional injection units are arranged upstream in the material flow direction. These additional injection units further improve the separation of the gas atmospheres and reliably prevent backflow of the following gas atmosphere. In further embodiments of the device, the injection units and / or suction units are divided transversely into several sections, each section comprising its own centered line for the supply and removal of gas. By this division into preferably equal-width sections, the flow conditions over the width of the lock are further improved and in addition the required power per line is reduced.

Embodiments of the device are characterized in that the injection units and / or suction units have a semicircular cross-section. Rounded cross-sections have aerodynamically advantageous geometries. Furthermore, the cross-section of the lock to be sealed is reduced by a blowing or suction unit placed on the lock wall.

Devices according to the invention are preferably operated with a method for separating gas atmospheres in a lock, which is characterized in that a larger volume flow of gas is withdrawn through the suction units than the volume flow of gas introduced by the adjacent injection unit. The withdrawn volume flow is in this case by 15% to 20% greater than the introduced by the adjacent injection unit volume flow. As a result, a negative pressure is generated on the downstream in the material flow direction of the atmosphere, which is largely ensured together with the gas curtain of the injection unit that no backflow takes place in the previous gas atmosphere.

Embodiments of the method according to the invention are characterized in that a further volume flow is introduced through additional blowing units arranged upstream in the material flow direction, wherein the total volume flow introduced corresponds to the extracted volume flow. As already explained for the device, the additional volume flow of the additional injection unit improves the separation of the gas atmospheres, since a pressure equalization with respect to the adjacent sections or gas atmospheres is achieved by the further volume flow. At the same time, by compensating for the injected and extracted volume flows, a removal of the upstream gas atmosphere in the material flow direction is largely prevented.

Preferred embodiments of the method are characterized in that opposite to the additional injection unit by the blowing unit adjacent to the suction unit one around the twice to four times, preferably three times, larger volume flow is introduced. As a result, the separation of the gas atmospheres is achieved by the suction unit and the adjacent injection unit and by the additional injection unit is a substantial decoupling of the gas atmospheres.

In embodiments of the method, the introduced volume flow is preheated, preferably to a temperature of 450 ° to 550 ° C. In particular, when used in continuous furnaces, galvanizing plants and other systems with elevated temperatures, it is advantageous if the injected gases are preheated to appropriate temperatures in order not to disturb the temperature management or heat treatment of the materials and to avoid condensation of components of the gas atmosphere. For example, for use in a proboscis of a galvanizing plant, the temperature is preferably in the range of 450 ° to 550 ° C. Using a device according to the invention operated with a described method takes place, for example, in a trunk of a fire-coating plant for the separation and removal of metal vapors.

Further use of a device according to the invention can take place, for example, in a continuous furnace for the separation of different gas atmospheres.

In addition to the examples mentioned, devices according to the invention can also be used in other areas in which gas atmospheres are separated from one another in a continuous process.

Short description of the drawings (Brief Description of Drawings)

In the following the invention will be explained in more detail with reference to schematic drawings, wherein similar components are provided with the same reference numerals. 1: a schematic injection unit viewed perpendicular to the material flow direction, FIG.

2 shows an embodiment of a suction unit and

Fig. 3: considered a lock according to the invention perpendicular to the material flow direction. Description of the Preferred Embodiments (Best Mode for Carrying Out the Invention)

Fig. 1 shows a schematic representation of an injection unit (1) according to the invention perpendicular to the material flow direction, more precisely perpendicular to the plane of the conveyed through material seen. Here, two rows of slot nozzles (2) are shown, each having interruptions or spaces between the slot nozzles (2). The slot nozzles (2) each have a width b and a length l. The two rows of slot nozzles (2) are removed from each other with a distance a in the material flow direction. The slot nozzles (2) of adjacent rows are offset relative to each other so that a break in one row is associated with a slot nozzle (2) of the adjacent row. The slot nozzles (2) are formed longer than the intervening interruptions, so seen in the material flow direction, an overlap u of the ends of the slot nozzles (2) is formed. The overlap u is formed uniformly along the injection unit.

In Fig. 2, a portion is shown, the lower injection unit (1) and suction unit (3) and parts of the upper injection unit (1) and suction unit (3) in the lock of an embodiment shows. The two opposite blowing units (1) on the upper and lower wall of the lock are shown, as well as the suction units (3) located downstream of the material flow direction, ie downstream. In this illustration, it can be seen that the slot nozzles (2) of the injection units (1) are arranged offset from each other. In addition to the offset between the rows on a blow-in unit (1), as already shown in FIG. 1, FIG. 2 also shows the offset of the slot nozzles (2) relative to the opposite blow-in unit (1). In the illustrated example, the outermost slot nozzle (2), seen in the width direction of the lock, is arranged in the front, ie upstream, row in the lower injection unit (1), and the rear, ie, downstream, row begins with an interruption. Accordingly, in the upper blowing unit (1), the outermost slot nozzle (1) is arranged in the rear row and the front row starts with an interruption. As a result of this arrangement, the gas streams emerging from the slot nozzles (2) pass unhindered in their main extent as far as the opposite lock wall, more precisely to the opposite blowing unit (1) or the material surface and contact with the gas flows takes place only in the region of the unavoidable areas of the beam widenings , By this embodiment, a gas curtain is achieved, which is very stable and has a very good sealing effect.

In the example shown in FIG. 2, both the suction units (3) and the injection units (1) are divided into several areas by intermediate walls (8) as viewed in the width direction. For the removal or supply of gas to the suction units (3) or blowing units (1), these each have lines (6), which are indicated in Fig. 2 in each case by round connection openings for the lines (6). Furthermore, in the illustrated example, the blowing units (1) and the suction units (3) are each formed with a semicircular cross-section which has flow-related advantages due to the avoidance of sharp edges.

Further, Fig. 2 shows a preferred embodiment of a suction unit (3). In this case, the main openings (4) are aligned in the material flow direction M in order to produce a circulating flow behind the device. The main openings (4) in the region of the lines (6) are in this case formed with a greater height in order to achieve relatively homogeneous flow conditions over the width. The height of the main openings (4) may change continuously or, as in the example shown, can jump. At the top of the suction units (3), additional openings (5) are preferably provided. Through this, in addition to an improvement of the suction also a shortening of the area of the circulating flow allows, which reduces the required space of the lock and favors the circulating flow. The additional openings may be formed with a uniform height across the width of the suction unit, or also analogously to the main openings (4) with different heights. For the example in a trunk of a fire-coating installation, the blowing units (1) and suction units (3) may be formed with a radius of 40 mm, for example, and the height of the main openings (4) in the range of 10 to 15 mm and the height of the additional openings (5 ) are at about 8mm. The lines (6) can then be formed in this example with a diameter of about 60mm. 3 shows a plan view of an embodiment of a lock according to the invention. Here, the injection unit (1) and the suction unit (3) located downstream in the material flow direction M are shown. Furthermore, an additional injection unit (7) is shown, which is arranged at a distance from the injection unit (1). The distance between the injection unit (1) and the additional injection unit (7) is preferably in the range from the width to the double width the lock. Using the example of a trunk of a fire-coating installation with a trunk width of about 1.9 m, the additional injection unit is thus preferably arranged at a distance of 2 m to 3 m from the injection unit (1). The various features of the invention can be combined with one another as desired and are not limited to the described or illustrated examples of embodiments.

LIST OF REFERENCE NUMBERS

1 injection unit

 2 slot nozzles

 3 suction unit

 4 main opening

 5 additional opening

 6 line

 7 Additional injection unit

8 intermediate wall a distance

 b width

 I length

 u overlap

 M material flow direction

Claims

claims 1. A device for separating gas atmospheres in a lock, which has over the transverse extent of the lock on opposite walls in each case at least one injection unit (1) and a suction unit (3), wherein the injection units (1) are provided directly opposite one another and the suction units (3) are arranged downstream in the material flow direction (M), characterized in that the blowing units (1) each have at least two rows of a plurality of slot nozzles (2) with intervening intersections, the slot nozzles (2) of the rows being offset from one another and the interrupts being shorter than the slot nozzles (2) of the adjacent row so that the slot nozzles (2) of the rows are in the material flow direction (M ) overlap, and that the slot nozzles (2) of a blowing unit (1) each opposite to an interruption of the opposite blowing unit (1). 2. Device according to claim 1, characterized in that the suction units (3) over the transverse extension provided for main openings (4), wherein the main openings (4) in the material flow direction (M) are aligned to produce a circulating flow. 3. Device according to one of claims 1 or 2, characterized in that the injection units (1) and suction units (3) each having at least one centered line (6) is connected to the supply or discharge of gas. 4. Apparatus according to claim 3, characterized in that the main openings (4) in the region of the centered line (6) have a greater height. 5. Device according to one of the preceding claims, characterized in that the suction units (3) additional openings (5), which are aligned perpendicular to the material flow direction (M). 6. Device according to one of the preceding claims, characterized in that the slot nozzles (2) have a width b, that the distance a between the rows in Range of b <a <2 * b, and that the overlap u of the slot nozzles (2) in the material flow direction (M) is in the range of b <u <3 * b, where additionally a <u. 7. Device according to claim 6, characterized in that the slot nozzles (2) have a length I in the transverse direction, wherein the length I in the range of 20 * b <I <50 * b, preferably in the range of 30 * b <I < 35 * b, lies. 8. Device according to one of the preceding claims, characterized in that additional injection units (7) in the material flow direction (M) are arranged upstream. 9. Device according to one of the preceding claims, characterized in that the injection units (1) and / or suction units (3) are divided in the transverse direction into several sections, each section comprising its own centered line (6) for supply or discharge of gas , 10. Device according to one of the preceding claims, characterized in that the injection units (1) and / or suction units (3) have a semicircular cross-section. 11. A method for separating gas atmospheres in a lock, wherein a device according to one of claims 1 to 10 is used, characterized in that a larger volume flow of gas through the suction units (3) is withdrawn than that by the adjacent injection unit (1). introduced volume flow of gas. 12. The method according to claim 11, characterized in that in the material flow direction (M) upstream arranged additional injection units (7), a further volume flow is introduced, wherein the total volume flow introduced corresponds to the extracted volume flow. 13. The method according to claim 12, characterized in that compared to the additional injection unit (7) by the suction unit (3) adjacent blowing unit (1) by a two times to four times, preferably three times, larger volume flow is introduced. 14. The method according to any one of claims 11 to 13, characterized in that the introduced volume flow is preheated, preferably to a temperature of 450 ° to 550 ° C. 15. Use of a device according to one of claims 1 to 10 operated by a method according to any one of claims 11 to 14 in a trunk of a fire-coating plant for the separation and removal of metal vapors. 16. Use of a device according to one of claims 1 to 10 operated with a method according to any one of claims 11 to 14 in a continuous furnace for the separation of different gas atmospheres.