WO2017211362A1

WO2017211362A1 - Exhaust and filtering system and method for dividing metal by-products process

Info

Publication number: WO2017211362A1
Application number: PCT/DK2016/050165
Authority: WO
Inventors: Thorkild Duusgaard STOKHOLM; Mads Bjørnsbæk LARSEN
Original assignee: Fractum 2012 Aps
Priority date: 2016-06-06
Filing date: 2016-06-06
Publication date: 2017-12-14

Abstract

Disclosed is an air filtering system (1) comprising a dividing shed (2) in which by-products (3) from a metal plant (4) can be divided into smaller pieces and wherein the dividing shed (2) comprising an air outlet (5). The air filtering system (1) further comprising a filtering unit (6) arranged to filter air and wherein the filtering unit (6) comprising an air inlet (7). The air filtering system (1) also comprises a displacement device (8) connected to the dividing shed (2) and to the filtering unit (6), wherein the displacement device (8) comprises displacement means (9) arranged to displace the dividing shed (2) in relation to the filtering unit (6). The air filtering system (1) further comprising a conduit (10) arranged to connect the air outlet (5) with the air inlet (7). Furthermore, a method for filtering air from a process of dividing by-products (3) from a metal plant (4) into smaller pieces is disclosed.

Description

EXHAUST AND FILTERING SYSTEM AND METHOD FOR DIVIDING METAL

BY-PRODUCTS PROCESS

Field of the invention

The invention relates to an air filtering system comprising a dividing shed in which by-products from a metal plant can be divided into smaller pieces. The invention further relates to a method for filtering air from a process of dividing by-products from a metal plant into smaller pieces.

Background of the invention

For many years by-products from metal plants, such as slag sculls, milling rolls, tundishes, ingot moulds and other kinds of scrap metal parts or other residual product from metal refinement plants have only rarely been reused. These by-products are typically very large and very heavy and therefore difficult to handle and so far they have typically merely been stored outside near the metal plant.

However, within resent years the cost of many types of metals have risen significantly and it has therefor become more and more desirable to reuse these byproducts. However, if these by-products are to be used in a metal refining, smelting and calcining process the by-products will have to be divided into smaller pieces to reduce the melting time and to ensure that the melting process can be better controlled. It is therefore known to divide these by-products - typically by means of a flame cutting process - but such a division process will typically produce toxic gasses or in other way generate unwanted air pollution. It is therefore an object of the present invention to provide for a cost-efficient technique alleviating the abovementioned drawbacks.

The invention

The invention provides for an air filtering system comprising a dividing shed in which by-products from a metal plant can be divided into smaller pieces and wherein the dividing shed comprising an air outlet. The air filtering system further comprises a filtering unit arranged to filter air and wherein the filtering unit comprising an air inlet. The air filtering system also comprises a displacement device connected to the dividing shed and to the filtering unit, wherein the displacement device comprises displacement means arranged to displace the dividing shed in relation to the filtering unit. The air filtering system further comprising a conduit arranged to connect the air outlet with the air inlet.

Connecting the dividing shed to the filtering unit through displacement means is advantageous in that it hereby is possible to move the shed around freely - within the working radius of the displacement device - to hereby enable that the shed is moved to, and placed around, the by-product e.g. instead of moving the by-products to a large stationary dividing plant. And since the dividing shed is made to substantially fit the by-products to be cut the air filtering system can be formed small and relatively inexpensive.

Furthermore, by connecting the dividing shed to the filtering unit through a displacement device is advantageous in that the relatively heavy filtering unit - arranged to filter the air evacuated from the dividing process in the dividing shed - hereby can act as a base or foundation to the crane-like arrangement to ensure stability of the air filtering system during displacement of the dividing shed.

In this context the term "displacement means" should be understood as any kind of crane, robot arm, jib, articulated lift arm or any other kind of displacer suitable for displacing a dividing shed in relation to a filtering unit.

In an aspect of the invention, the conduit is arranged in or on or connected to the displacement device. Arranging the conduit in, on or at least connected to the displacement device is advantageous in that the conduit hereby is protected and will follow the displacement device around when the dividing shed is repositioned - thus, ensuring efficient setup. In an aspect of the invention, the conduit is formed by at least a part of a load- carrying structure of the displacement device.

Using at least a part of the load-carrying structure of the displacement device to form the conduit is advantageous in that it will reduce cost and weight and it will ensure that the conduit is protected.

In an aspect of the invention, a first end of the displacement device is connected to the filtering unit and a second end of the displacement device is connected to the dividing shed.

Hereby is achieved an advantageous embodiment of the invention.

In an aspect of the invention, the filtering unit is formed as at least one standard 20 foot or 40 foot ISO container.

Forming the filtering unit as a standardized forty or twenty foot container is advantageous in that the filtering unit then can be transported efficiently and inexpensively within the global containerized intermodal freight transport system. An ISO container - also known as freight container, intermodal container, shipping container, hi-cube container, box, conex box or sea can - is a standardized reusable box used for the safe, efficient and secure storage and movement of materials and products within the global containerized intermodal freight transport system. In an aspect of the invention, the outer contour of said filtering unit is substantially formed as a forty foot ISO container having an external length, width and height of approximately 12.192, 2.438 and 2.896 meters or as a twenty foot ISO container having an external length, width and height of approximately 6.058, 2.438 and 2.896 meters.

To ensure that the filtering unit can be fixated during use as or during storage and transportation it is advantageous to provide each corner with a twistlock fitting. Furthermore, given the existing amount of equipment suitable for handling ISO containers etc. provided with twistlock fittings, the twistlock fitting will make handling of the filtering unit less expensive.

By the term "twistlock fitting" is to be understood a corner casting fitted at each corner of the module. The twistlock fitting has an approximate size of 7x7x4.5 inches (180x 180x 1 10 mm) and is provided with slits (which are roughly 4.1 inches (104.1 mm) long and 2.2 inches (55.9 mm) wide) so that it can act as the female part of a twistlock connector where the male component is the twistlock itself, which is fitted to e.g. a crane or transport bases. The twistlock can be inserted through the slits in the twistlock fitting whereafter then the top portion of the twistlock (normally pointed to make insertion easier) is rotated 90° so that it cannot be withdrawn. The mechanism is the same as that of a Kensington lock, but on a much larger scale. The twistlock is also known as a Tantlinger lock.

In an aspect of the invention, the filtering unit comprises a plurality of cartridge filters or bag filters.

Using cartridge filters or bag filters in the filtering unit is an efficient way of achieving a large filtering surface in a relatively small space. Furthermore, cartridge filters or bag filters in the filtering unit is efficient at reducing sediments from the dividing process transported by the air through the conduit. In an aspect of the invention, the displacement device has a working radius of at least 5 meters.

Providing the displacement device with a relatively large working radius is advantageous in that it makes the air filtering system more efficient in that the entire air filtering system does not have to be moved as often. In an aspect of the invention, the displacement means comprises rotating means for rotating the dividing shed in relation to the displacement device.

Providing the displacement means with rotating means is advantageous in that it hereby is possible to easily adjust the position of the dividing shed in relation to the wind, in relation to the object to be cut, in relation to the ground or other.

By the term "rotating means" is to be understood any kind of rotary joint, pivot joint, rotary coupling or any other kind of rotator enabling relative rotation between the dividing shed and the displacement device. This rotating means could be manually driven - i.e. the operator would have to manually push the dividing shed to rotate it in relation to the displacement means - which is advantageous in that it provided for simple and inexpensive rotating means.

However, in another embodiment the rotating means could comprise driving means in the form of a motor, a rotary actuator, a rack and pinion arrangement or another type of driver suited for driving the rotation of the dividing shed in relation to the displacement device. Use of such driving means is advantageous in that it enable simple and precise placement of the dividing shed even if the dividing shed is heavy and therefore difficult to position by hand. Furthermore, when the driving means are not activated they could also act as a form of lock of the rotating means so that the dividing shed can only be rotated in relation to the displacement means when the driving means is activated whereas these means will by nature be locked against rotation or at least impair the rotating means ability to rotate when not activated.

In an aspect of the invention, the displacement means comprises locking means for locking the rotation of said rotating means. When actuating the displacement means it could be advantageous that the dividing shed is not able to turn in relation to the displacement device e.g. to ensure that the dividing shed is not caught by the wind, to ensure a more precise placement of the dividing shed or other. By the term "locking means" is to be understood any kind of latch, bolt, catch or any kind of lock suitable for being locked or unlocked to selectively lock the rotary motion between the dividing shed and the displacement device.

In an aspect of the invention, the dividing shed can be rotated 360 deg substantially horizontal plane.

Enabling that the dividing shed can be rotated 360 degrees in a substantially horizontal plane is advantageous in that the dividing shed hereby can be positioned more optimally.

In an aspect of the invention, the air filtering system comprises a remote control by means of which the displacement means can be operated. It is advantageous that the displacement means can be operated by means of a remote control in that the operator hereby can position the dividing shed more precisely in that the operator can be closer to the by-product and the shed during the positioning process.

In an aspect of the invention, the filtering unit is self-propelled.

Providing the filtering unit with means enabling it to move around is advantageous in that it hereby can be positioned more quickly and advantageously on the by-product site.

In an aspect of the invention, the filtering unit comprises a vehicle.

Loading the filtering unit e.g. on a flatbed truck to move it around is advantageous in that it is a simple and relatively inexpensive way of propelling the filtering unit. Furthermore, the displacement means can then be connected to this vehicle.

In an aspect of the invention, the dividing shed comprises a work opening in the form of an aperture in one of the sides of the dividing shed.

Hereby is achieved an advantageous embodiment of the invention.

In an aspect of the invention, the air outlet is arranged opposite the work opening. The operator will have to stand in or near the work opening when dividing the byproduct in the shed. Thus, smoke, dust, debris and other will be blown in the opposite direction. It is therefore advantageous to locate the air outlet opposite the work opening. In an aspect of the invention, the air outlet is arranged at the top of the dividing shed. The dividing usually takes place at very high temperatures and this process will then generate very hot smoke. This very hot smoke will quickly raise to the top of the shed and it is therefore advantageous that the air outlet is located at or at least near the top of the shed.

In an aspect of the invention, at least a part of the inside surface of the dividing shed comprises refractory material. Cutting through large metal objects requires much heat and energy and will typically produce much thermal radiation and splashes of melted metal. It is therefore advantageous to line at least a part of the inside surface of the dividing shed with refractory material. In this context a refractory material is one that retains its strength at high temperatures i.e. refractory materials include non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 1,000 °F (811 K; 538 °C).

Refractory materials must be chemically and physically stable at high temperatures. Depending on the operating environment, they need to be resistant to thermal shock, be chemically inert, and/or have specific ranges of thermal conductivity and of the coefficient of thermal expansion.

The oxides of aluminum (alumina), silicon (silica) and magnesium (magnesia) are the most important materials used in the manufacturing of refractories. Another oxide usually found in refractories is the oxide of calcium (lime). Fire clays can also be used in the manufacture of refractories. Also binary compounds such as tungsten carbide, Hafnium carbide or boron nitride can be used or included in refractory material.

In an aspect of the invention, the refractory material is formed as tiles.

Forming the refractory material as tiles is advantageous in that they hereby are easier to handle and replace.

In an aspect of the invention, the tiles are hung from the inside surface.

Merely hanging the tiles from the inside surface of the shed is advantageous in that they hereby can be replaced substantially without the use of tools.

In an aspect of the invention, the dividing shed is connected to the displacement device through a quick release coupling.

Connecting the dividing shed the displacement device through a quick release coupling is advantageous in that the dividing shed hereby can easily be exchanged e.g. in case repair or e.g. to use a specific shed designed to a specific task.

A quick release coupling - also called a quick coupler or quick hitch - is typically used with construction machines and similar machinery to allow the rapid change of attachments on the machine. They remove the need to use hammers or other tools to e.g. manually drive out and insert mounting pins for attachments.

In an aspect of the invention, the displacement device comprises an articulated lift arm and/or a telescopic arm. Using an articulated lift arm and/or a telescopic arm is advantageous in that it hereby is possible to easily utilise the entire working area of the displacement device. In an aspect of the invention, the displacement means comprises hydraulic actuators.

Hydraulic actuators are very strong in relation to their size and are therefore particularly suited to form part of the displacement means.

In an aspect of the invention, the hydraulic actuators are driven by a hydraulic pump placed in the filtering unit.

Locating the hydraulic pump in the filtering unit is advantageous in that the hydraulic pump hereby is better protected, it has easy access to power and it will follow the filtering unit around when moved.

In an aspect of the invention, the air filtering system comprises a wind direction indicator.

Providing the air filtering system with a wind direction indicator is advantageous in that it hereby is easier to position the dividing shed correctly in relation to the wind.

In an aspect of the invention, the dividing shed comprises a number of smaller work opening.

Providing the shed with a number of small openings - such as a number of vertical slits in the sides of the shed - is advantageous in that it hereby is possible to cut the by-product through the slits - e.g. by means of lansing - while better protecting the operator against hot splashes and against the harmful smoke generated during the dividing process. Furthermore, the smaller work openings could advantageously be formed so small that the operator could not enter through then and this shed design would then also ensure that the operator is protected from touching the hot byproduct during or after the cutting process. In an aspect of the invention, at least some of said number of smaller work opening is provided with doors.

Providing the smaller work openings with doors is advantageous in that the air flow into the shed hereby can be better controlled. I.e. the doors are normally closed and the operator then only opens the one that he currently need to cut the by-product. Thereby in-flow is substantially limited to the open door and the risk of smoke exciting though this smaller work opening is reduced.

The invention also provides for a method for filtering air from a process of dividing by-products from a metal plant into smaller pieces. The method comprises the steps of:

• arranging an air filtering system at a site including the by-products from a metal plant,

• displacing a dividing shed in relation to a filtering unit of the air filtering system by means of a displacement device connected to the dividing shed and the filtering unit to make the dividing shed at least partly enclose at least one by-product,

• divide the by-product into smaller pieces in the dividing shed,

• evacuate air from the dividing shed to the filtering unit through a conduit arranged at the displacement device during the by-product dividing process, and filter the evacuated air in the filtering unit. Displacing the dividing shed in relation to the filtering unit is advantageous in that the dividing shed hereby quickly and easily can be position around all the byproducts inside the working radius of the displacement device - i.e. one after the other.

In an aspect of the invention, the method further comprises the step of arranging the dividing shed so that a work opening of the dividing shed substantially faces the wind. Making the work opening of the dividing shed substantially face the wind during the dividing process is advantageous in that the wind will then aid in forcing smoke and other pollutants into the air outlet to be filtered in the filtering unit. Furthermore, by making the work opening of the dividing shed substantially face the wind, the wind will aid in forming an over pressure that will increase the efficiency of the air filtering system.

In an aspect of the invention, the by-product is divided the into smaller pieces through more than one work opening in the dividing shed. By cutting the by-product through more than one work opening in the sides of the shed the operator can have better access to the by-product while at the same time being better protected in that each of this number of work opening now can be formed so small that the operator cannot enter through them. In an aspect of the invention, the by-product is divided into smaller pieces by means of lancing.

Lancing (also Thermal or Oxygen lancing) is a method used to cut through thick material using oxygen. Pressurized oxygen is fed through a burning steel tube, forming a flame capable of cutting through even very thick metal objects. The typical temperatures for cutting ranges from 2,000 to 4,000 degrees Celsius. It is therefore advantageous to use lancing to divide the by-products and thereby heat and melt the by-products with pressurized oxygen to create extremely high temperatures which is used for cutting the by-products no matter if they are made of iron, steel, aluminum, magnesium, nickel, cobber or other metals or any combination thereof.

In an aspect of the invention, the air is filtered by means of an air filtering system according to any of the previously mentioned air filtering systems. Hereby is achieved an advantageous embodiment of the invention.

Even further the invention relates to an automated dividing unit by means of which by-products from a metal plant can be divided into smaller pieces. The dividing device includes a dividing shed comprising or being connected to a displacement device arranged to displace the dividing shed in relation to the by-product. The dividing device further comprises contour means arranged to detect a contour of the by-product, wherein the contour means is arranged inside the dividing shed, and the dividing unit comprises dividing means arranged to divided the by-product into smaller pieces on the basis of information from the contour means, wherein the dividing means is also arranged inside the dividing shed.

Dividing by-products from a metal plant by means of an automated dividing unit is advantageous in that the dividing process generates much heat and pollution and it is therefore difficult or undesirable to perform this operation manually.

Furthermore, by dividing the by-product by means of dividing means on the basis of a detecting contour of the by-product is advantageous in that it hereby is possible to easily adapt the dividing process to different embodiments of by-products. In this context the term "contour means" should be understood as any kind of camera, radar, ultrasonic sensor or any other kind of contour detector suitable for detecting a contour of a by-product from a metal plant. Furthermore, in this context the term "dividing means" should be understood as any kind of arrangement comprising a oxy-fuel cutter, a laser cutter, a saw or any other kind of divider suitable for dividing by-product from a metal plant into smaller pieces. In an aspect of the invention, the dividing shed comprises a guarded door arranged so that the dividing means can only operate if the door is closed from outside the dividing shed.

Automated dividing means for dividing by-products are dangerous in operation and for that reason and to ensure efficient air evacuation during the dividing process it is advantageous to provide the dividing shed with a guarded door.

In an aspect of the invention, the automated contour means comprises one or more cameras.

Detecting the contour of the by-products by means of a camera is quick, efficient and relatively inexpensive.

In an aspect of the invention, the dividing means comprises a cutting tool being actuated by a robot or a robot-like arrangement.

Actuating the cutting tool by means of a robot, a XYZ actuator, a multiple-joint arrangement or similar robot-like arrangements having at least three degrees of freedom is advantageous in that it enables efficient cutting of by-products having even very complex contours. In an aspect of the invention, the automated dividing unit comprises an air filtering system according to any of the previously mentioned air filtering systems. The invention also relates to a method of dividing a by-product from a metal plant into smaller pieces. The method comprises the steps of:

• displacing a dividing shed to make the shed substantially enclose the byproduct,

· detecting a contour of the by-product in the dividing shed, and

• divide the by-product into smaller pieces in the dividing shed by means of automated dividing means of the dividing shed on the basis of said contour detection. Placing the dividing shed over the by-product before the dividing process is advantageous in that this enables that the dividing process may be performed under more controlled circumstances. Furthermore, the dividing shed will protect the surrounding from harmful effects of the dividing process (radiation, smoke, hot splashes etc.).

In an aspect of the invention, the method further comprises the step of evacuate air from the dividing shed to a filtering unit during the by-product dividing process.

The smoke and other pollutants generated during the by-product dividing process can be toxic or environmentally harmful and it is therefore advantageous to evacuate air from the dividing shed to a filtering unit during the by-product dividing process to enable filtering and/or cleaning or the air.

In an aspect of the invention, the method is performed on an automated dividing unit according to any of the previously discussed automated dividing units. Figures

The invention will be described in the following with reference to the figures in which fig. 1. illustrates an air filtering system with the displacement device arranged on the filtering unit, as seen from the front, fig. 2 illustrates an air filtering system where the filtering unit comprises a vehicle, as seen from the front, fig. 3 illustrates an air filtering system on a by-product site, as seen from the top, fig. 4 illustrates a cross section through a filtering unit, as seen from the front, fig. 5 illustrates a cross section through a dividing shed, as seen from the side, fig. 6 illustrates a dividing shed, as seen from the front, and fig. 7 illustrates an automated dividing unit, as seen from the front.

Detailed description

Fig. 1 illustrates an air filtering system 1 with the displacement device 8 arranged on the filtering unit 6, as seen from the front. In this embodiment the air filtering system 1 comprises a filtering unit 6 placed on the ground at a by-product site - i.e. a site where by-products 3 from a metal plant (see fig. 3) - such as a steel mill, an aluminium plant or other - is stored. Typically, these by-products 3 are stored outside near the metal plant but the by-product 3 could also be store remote and/or in large indoor storage facilities.

In this case the by-product 3 is a slag scull from a steel plant but is another embodiment the by-products 3 could be slag from another type of metal plant - such as an aluminium plant, an iron plant, a metal moulding plant, an alloy manufacturing plant, a gold foundry or another type of metal plant - and/or the by-product 3 could instead of slag be milling rolls, tundishes, ingot moulds and other kinds of scrap metal parts or other residual metal or metal-containing products from a metal plant.

In this embodiment the air filtering system 1 also comprises a dividing shed 2 in which the by-product 3 can be divided into smaller parts that more easily can be handled and more efficiently can be reused in the production in the metal plant.

The by-products 3 are typically very large and very heavy and therefore difficult to handle and it is therefore advantageous to move the dividing shed 2 around on the by-product site to enclose different by-products 3 instead of moving the by-products 3 to a central stationary dividing facility.

To enable displacement of the dividing shed 2 the shed 2 is connected to a displacement device 8 based on the roof of the filtering unit 6. However, in another embodiment the displacement device 8 could instead or also be connected to the sides or the foundation of the filtering unit 6.

In this embodiment the displacement device 8 comprises a telescopic lift arm that can rotate and be extended. When by-products 3 are divided in the dividing shed 2 harmful smoke is generated an in this embodiment this smoke is evacuated from the dividing shed 2 and over to the filtering unit 6 by means of a conduit 10 in the form of a hose. However, in another embodiment the conduit 10 could instead or also comprise pipes, tubes, ducts or other. In this embodiment the conduit 10 is arranged outside the displacement device 8 but in another embodiment at least parts of the conduit 10 could be arranged in or form part of a part of the displacement device 8.

Fig. 2 illustrates an air filtering system 1 where the filtering unit 6 comprises a vehicle 17, as seen from the front.

Even if the displacement device 8 has a very large working radius WR the air filtering system 1 will still have to be moved from time to time and in this embodiment the filtering unit 6 comprises a vehicle 17 in the form of a flatbed truck. However, in another embodiment the vehicle 17 could be a fork lift, a tractor, a lorry or the filtering unit 6 could instead comprise wheels, be placed or a trailer or a trolley or in other way be provided with means enabling increased mobility of the air filtering system 1. In this embodiment the displacement device 8 is connected to the vehicle 17 and is in this embodiment formed as an articulate lift arm 21 as e.g. can be seen on an excavator. The displacement device 8 comprises displacement means 9 in the form of hydraulic actuators 22 arranged to drive the motion of the displacement device 8. However, in another embodiment the displacement means 9 could be pneumatic actuators, electrical actuators or other.

Fig. 3 illustrates an air filtering system 1 on a by-product site, as seen from the top.

In this embodiment a first end 12 of the displacement device 8 is mounted on or at the filtering unit 6 while the second end 13 of the displacement device 8 is connected to the dividing shed 2. In this embodiment the displacement device 8 can rotate in relation to the filtering unit 6 so that the dividing shed 2 can be placed substantially anywhere within the working radius WR of the displacement device 8. In this embodiment the working radius WR of the displacement device 8 is around 5 meters but in another embodiment the working radius could be smaller such as 3 or 4 meters or bigger such as 6, 8, 10 meters or even more.

In this embodiment the dividing shed 2 comprises rotating means 15 enabling that the dividing shed 2 can be rotated in relation to the displacement device 8 - so that the dividing shed 2 may be placed more advantageously in relation to the object to be cut, in relation to the wind, in relation to the ground or other.

In this embodiment the by-product site is the surrounding outside area of a metal plant 4.

Fig. 4 illustrates a cross section through a filtering unit 6, as seen from the front.

In this embodiment the filtering unit 6 comprises cartridge filters 14 arranged to filter the air drawn from the dividing shed 2 before the filtered air is blown out. However, in another embodiment the filtering unit 6 could instead or also comprise bag filters, cyclone filters, impingement filter, water bath air cleaners or other types of arrangements or devices capable of removing solid particulates such as dust, pollen, mould, and/or bacteria from the air. The filtering unit 6 could also or instead comprise a chemical air filter comprising an absorbent or catalyst for the removal of airborne molecular contaminants such as volatile organic compounds or ozone.

In this embodiment the filtering unit 6 also comprises additional equipment 32 in the form of a motor driven fan arranged to generate an air flow through the conduit 10 from the dividing shed 2 to and through the filtering unit 6. In this embodiment the additional equipment 32 also comprises a spark absorber arranged to ensure that sparks in the air flow does not reach the filters 14. In this embodiment the additional equipment 32 is arranged at the air inlet 7 in the filtering unit 6 but in another embodiment at least parts of the additional equipment 32 could be arranged elsewhere in the filtering unit 6.

In this embodiment the displacement means 9 of the displacement device 8 comprises hydraulic actuators 22 and in this embodiment these actuators are driven by a hydraulic pump 23 arranged inside the filtering unit 6. However, in another embodiment the pump 23 could be arranged on the displacement device 8, outside the filtering unit 6, as a remote power source or other.

In this embodiment the filtering unit 6 comprises a 20-foot standard ISO container inside which all the filters 14 and additional equipment 32 are arranged. In this way the filtering unit 6 can easily be moved and the filters 14 and additional equipment 32 are well protected. Thus, in this embodiment all the corners of the filtering unit 6 is provided with twistlock fittings 33.

However, in another embodiment the filtering unit 6 could comprises a standard ISO container of another size or the filtering unit 6 could be arranged inside another type of container.

Fig. 5 illustrates a cross section through a dividing shed 2, as seen from the side, and fig. 6 illustrates a dividing shed 2, as seen from the front. In this embodiment a deflector 34 is arranged in front of the air outlet 5 of the dividing shed 2. The deflector 34 is arranged to deflect and thereby prevent splashes and other physical objects from entering the conduit 10 connected to the outlet 5.

In this embodiment the air outlet 5 is arranged in the back wall opposite the work opening 18 but in another embodiment the shed 2 could comprise more than one air outlet 18 and the outlets 18 could be located differently in the shed 2. Particularly, in another embodiment the air outlet 18 could be located in the roof of the shed 2 to better inhale the ascending smoke in the shed 2 - e.g. a substantially centrally arranged air outlet 18 enabling better air inhalation no matter from which side air inflow is established. In such an embodiment the shed 2 could also be provided with a air flow guides in the form of sloping surfaces guiding the accenting smoke upwards towards the air outlet 18.

In this embodiment all the inside surfaces of the dividing shed 2 are covered with refractory material 19. However, in another embodiment only some of the inside surfaces of the dividing shed 2 would be covered by refractory material 19, such as only some of the sides, or in another embodiment one or more parts of the dividing shed 2 would be formed by refractory material 19. In this embodiment the refractory material 19 is formed as interlocking tiles but in another embodiment the tiles could be attached to the inside surfaces by means of connection means - such as clips, clams, rivets, screws, bolts, adhesive or other - or the refractory tiles could be hung on protrusions on the walls or from the roof to make it easier to replace damaged tiles.

In this embodiment the dividing shed 2 comprises only a single layer of refractory material 19 but in another embodiment the refractory material 19 could at least partly be formed in at least two individual layers enabling that joints in the inner layer can be covered by the outer layer.

In this embodiment the dividing shed 2 is provided with a simple wind direction indicator 24 but in another embodiment the wind direction indicator 24 could be placed elsewhere or be automated. In this embodiment the dividing shed 2 is provided with a work opening 18 through which the operator may enter the shed 2 to manually divide the by-product 3 located inside the shed 2. In this embodiment the work opening 18 is formed at an entire open side in the shed 2 but in another embodiment the work opening 18 could comprise more sides of the shed 2, it could be formed as a smaller aperture in a side and/or the work opening 18 could comprise a door or another covering device. In another embodiment the dividing shed 2 could be provided with a number of work opening 18 distributed over more than one side of the shed 2 - advantageously at least one work opening 18 in every side of the shed 2, particularly is the air out let was arranged in a top surface of the shed 2. This number of work openings 18 could then e.g. be formed at vertical slits enabling that the operator can bot work and see through the opening 18 but at the same time the slits are so narrow that the air-inflow is concentrated over a relatively small area, thus increasing air flow speed and reducing the risk of backwash, and protecting the operator better.

In this embodiment the dividing shed 2 is connected to the displacement device 8 through a quick release coupling 20 enabling that the dividing shed 2 can easily and remotely be separated from the displacement device 8 to enable that the dividing shed 2 easily can be exchanged e.g. to a shed 2 of a different size or to do repairs.

In this embodiment the process of dividing by-products 3 into smaller pieces comprises the following steps of:

• arranging the air filtering system 1 at the by-product site e.g. by means of a separate vehicle 17 or an included vehicle 17 or other propulsion means as discussed in relation to figs. 1 and 2,

• moving the dividing shed 2 in relation to the filtering unit 6 by means of a displacement device to place the dividing shed 2 so that it at least partly enclose a by-product3. This displacement could e.g. be performed by the operator by means of a remote control 16, • divide the by-product 3 into smaller pieces in the dividing shed 2, either manually e.g. by means of lansing or by means of automated dividing means,

• evacuate air from the dividing shed 2 to the filtering unit 6 through the conduit 10 arranged at the displacement device 8, and

· filter the evacuated air in the filtering unit 6, before the filtered air is released to the surroundings or used for another purpose.

Fig. 7 illustrates an automated dividing unit 31, as seen from the front. In this embodiment the dividing shed 2 is provided with contour means 25 arranged to detect the outer contour of the by-product 3 inside said dividing shed 2, and automated dividing means 26 arranged to divided the by-product 3 into smaller pieces on the basis of information from the contour means 25. Thus in this embodiment the dividing shed 2, the contour means 25 and the dividing means 26 together form an automated dividing unit 31.

In this embodiment the contour means 25 comprises a number of cameras 28 hung from the inside of the dividing shed 2 so that substantially the entire visible outer contour of the by-product 3 can be detected by the contour means 25 - obviously except the surface on which the by-product 3 rests against the underground.

But in another embodiment the contour means 25 could also or instead comprise proximity sensors, laser sensor, ultrasound sensors, radars or other and/or the contour means 25 could be integrated in or mounted on the dividing means 26.

In this embodiment the dividing means 26 comprises a standard industrial robot 30 provided with a cutting tool 29 in the form of a high power flame cutter. However, in another embodiment the dividing means 26 could instead of an industrial robot 30 comprise some kind of manipulator, automated displacement system, another robot or robot-like arrangement or any combination thereof and/or in another embodiment the cutting tool 29 could also or instead comprise a plasma cutter, another type of arc cutter, a saw or another type of tool suited for dividing a by-product 3 from a metal plant into smaller pieces. In this embodiment the work opening 18 of the dividing shed 2 is provided with a door 27 comprising a door sensor 35 arranged to detect if the door 27 is closed or not. In this embodiment the automated dividing unit 31 is arranged so that the dividing means 26 can only operate automatically when the door sensor 35 detects that the door 27 is closed. By placing start buttons or similar on the outside of the shed 2 it can hereby be ensured that the dividing means 26 can only be activated when the operator is outside the shed 2 and the door 27 is shut.

In this embodiment the process of dividing by-product 3 into smaller pieces comprises the steps of:

• displacing the dividing shed 2 to make the shed substantially enclose said byproduct 3, e.g. by means of the displacement device previously disclosed,

• detecting at least a part of the outer contour of the by-product 3 in the dividing shed 2, and

· divide the by-product 3 into smaller pieces by means of the automated dividing means 26 on the basis of the contour detection.

The invention has been exemplified above with reference to specific examples of air filtering systems 1, dividing sheds 2, displacement devices and other. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims. List

1. Air filtering system

2. Dividing shed

3. By-product

4. Metal plant

5. Air outlet

6. Filtering unit

7. Air inlet

8. Displacement device

9. Displacement means

10. Conduit

11. Load-carrying structure of displacement device

12. First end of displacement device

13. Second end of displacement device

14. Cartridge filters

15. Rotating means

16. Remote control

17. Vehicle

18. Work opening

19. Refractory material

20. Quick release coupling

21. Articulated lift arm

22. Hydraulic actuators

23. Hydraulic pump

24. Wind direction indicator

25. Contour means

26. Dividing means

27. Guarded door

28. Camera

29. Cutting tool 30. Robot

31. Automated dividing unit

32. Additional equipment 33. Twistlock fitting

34. Deflector

35. Door sensor

WR. Working radius

Claims

1. An air filtering system (1) comprising a dividing shed (2) in which by-products (3) from a metal plant (4) can be divided into smaller pieces, said dividing shed (2) comprising an air outlet (5), said air filtering system (1) further comprising a filtering unit (6) arranged to filter air, said filtering unit (6) comprising an air inlet (7), said air filtering system (1) also comprises a displacement device (8) connected to said dividing shed (2) and to said filtering unit (6), wherein said displacement device (8) comprises displacement means (9) arranged to displace said dividing shed (2) in relation to said filtering unit (6), and said air filtering system (1) further comprising a conduit (10) arranged to connect said air outlet (5) with said air inlet (7).

2. An air filtering system (1) according to claim 1, wherein said conduit (10) is arranged in or on or connected to said displacement device (8).

3. An air filtering system (1) according to claim 1 or 2, wherein said conduit (10) is formed by at least a part of a load-carrying structure (11) of said displacement device (8).

4. An air filtering system (1) according to any of the preceding claims, wherein a first end (12) of said displacement device (8) is connected to said filtering unit (6) and a second end (13) of said displacement device (8) is connected to said dividing shed (2).

5. An air filtering system (1) according to any of the preceding claims, wherein said filtering unit (6) is formed as at least one standard 20 foot or 40 foot ISO container.

6. An air filtering system (1) according to any of the preceding claims, wherein said filtering unit (6) comprises a plurality of cartridge filters (14) or bag filters.

7. An air filtering system (1) according to any of the preceding claims, wherein said displacement device (8) has a working radius (WR) of at least 5 meters.

8. An air filtering system (1) according to any of the preceding claims, wherein said displacement means (9) comprises rotating means (15) for rotating said dividing shed (2) in relation to said displacement device (8).

9. An air filtering system (1) according to any of the preceding claims, wherein said dividing shed (2) can be rotated 360 degrees in a substantially horizontal plane.

10. An air filtering system (1) according to any of the preceding claims, wherein said air filtering system (1) comprises a remote control (16) by means of which said displacement means (9) can be operated.

11. An air filtering system (1) according to any of the preceding claims, wherein said filtering unit (6) is self-propelled.

12. An air filtering system (1) according to any of the preceding claims, wherein said filtering unit (6) comprises a vehicle (17).

13. An air filtering system (1) according to any of the preceding claims, wherein said dividing shed (2) comprises a work opening (18) in the form of an aperture in one of the sides of said dividing shed (2).

14. An air filtering system (1) according to claim 13, wherein said air outlet (5) is arranged opposite said work opening (18).

15. An air filtering system (1) according to any of the preceding claims, wherein at least a part of the inside surface of said dividing shed (2) comprises refractory material (19).

16. An air filtering system (1) according to claim 15, wherein said refractory material (19) is formed as tiles.

17. An air filtering system (1) according to claim 16, wherein said tiles are hung from said inside surface.

18. An air filtering system (1) according to any of the preceding claims, wherein said dividing shed (2) is connected to said displacement device (8) through a quick release coupling (20).

19. An air filtering system (1) according to any of the preceding claims, wherein said displacement device (8) comprises an articulated lift arm (21) and/or a telescopic arm.

20. An air filtering system (1) according to any of the preceding claims, wherein said displacement means (9) comprises hydraulic actuators (22).

21. An air filtering system (1) according to claim 20, wherein said hydraulic actuators (22) are driven by a hydraulic pump (23) placed in said filtering unit (6).

22. An air filtering system (1) according to any of the preceding claims, wherein said air filtering system (1) comprises a wind direction indicator (24).

23. A method for filtering air from a process of dividing by-products (3) from a metal plant (4) into smaller pieces, said method comprising the steps of:

• arranging an air filtering system (1) at a site including said by-products (3) from a metal plant (4),

• displacing a dividing shed (2) in relation to a filtering unit (6) of said air filtering system (1) by means of a displacement device (8) connected to said dividing shed (2) and said filtering unit (6) to make said dividing shed (2) at least partly enclose at least one by-product (3),

• divide said by-product (3) into smaller pieces in said dividing shed (2),

• evacuate air from said dividing shed (2) to said filtering unit (6) through a conduit (10) arranged at said displacement device (8) during said by-product dividing process, and

• filter said evacuated air in said filtering unit (6).

24. A method according to claim 23, wherein said method further comprises the step of arranging said dividing shed (2) so that a work opening (18) of said dividing shed (2) substantially faces the wind.

25. A method according to claim 23 or 24, wherein said by-product (3) is divided into smaller pieces by means of lancing.

26. A method according to any of claims 23 to 25, wherein said air is filtered by means of an air filtering system (1) according to any of claims 1-22.

27. An automated dividing unit (31) by means of which by-products (3) from a metal plant (4) can be divided into smaller pieces, said dividing unit comprises, a dividing shed (2) comprising or being connected to a displacement device (8) arranged to displace said dividing shed (2) in relation to said by-product (3), contour means (25) arranged to detect a contour of said by-product (3), wherein said contour means (25) is arranged inside said dividing shed (2), and dividing means (26) arranged to divided said by-product (3) into smaller pieces on the basis of information from said contour means (25), wherein said dividing means (26) is also arranged inside said dividing shed (2).

28. An automated dividing unit (31) according to claim 27, wherein said dividing shed (2) comprises a guarded door (27) arranged so that said dividing means (26) can only operate if said door (27) is closed from outside said dividing shed (2).

29. An automated dividing unit (31) according to claim 27 or 28, wherein said automated contour means (25) comprises one or more cameras (28).

30. An automated dividing unit (31) according to any of claims 27 to 29, wherein said dividing means (26) comprises a cutting tool (29) being actuated by a robot (30) or a robot-like arrangement.

31. An automated dividing unit (31) according to any of claims 27 to 30, wherein said automated dividing unit (31) comprises an air filtering system (1) according to any of claims 1-22.

32. A method of dividing a by-product (3) from a metal plant (4) into smaller pieces, said method comprises the steps of: • displacing a dividing shed (2) to make said shed substantially enclose said by-product (3),

• detecting a contour of said by-product (3) in said dividing shed (2), and

• divide said by-product (3) into smaller pieces in said dividing shed (2) by means of automated dividing means (26) of said dividing shed (2) on the basis of said contour detection.

33. A method according to claim 32, wherein said method further comprises the step of evacuate air from said dividing shed (2) to a filtering unit (6) during said byproduct (3) dividing process.

34. A method according to claim 32 or 33, wherein said method is performed on an automated dividing unit (31) according to any of claims 27 to 31.