WO2006083176A1

WO2006083176A1 - Cleaning device

Info

Publication number: WO2006083176A1
Application number: PCT/NO2006/000046
Authority: WO
Inventors: Per Erik Steiro; Gunnar Nisja; Ulf BERSÅS; Aslak Aastorp; Knut MÅLØY
Original assignee: STORVIK AS
Current assignee: STORVIK AS
Priority date: 2005-02-07
Filing date: 2006-02-03
Publication date: 2006-08-10
Anticipated expiration: 2007-08-07
Also published as: NO322239B1; NO20050651D0

Abstract

A cleaning device (1) for removing slag and metal residues from tapping crucibles (7) for molten metal, comprising a frame (2) on which is arranged a movable slide (3) that is provided with a rotating cutting tool (4) of the full profile type equipped with a tool head (14), and wherein on the frame (2) there is arranged a travelling crane (5) with a lifting cage (6) for tapping crucibles (7) which can collect, lift and tilt the tapping crucible (7) from a lower position with its opening in a horizontal plane to an upper position for cleaning in which the opening is in a plane that is at 90° to the cutting tool axis (18) and in which the tapping crucible axis (19) is coincident with the cutting tool axis (18), and wherein the cutting tool axis (18) is essentially coincident with the horizontal plane.

Description

Cleaning device

The present invention relates to a cleaning device for removing slag and metal residues from crucibles/tapping crucibles for molten metal, the cleaning device comprising a frame on which is arranged a movable slide that is provided with a rotatable cutting tool of the full profile type.

Crucibles that are used for tapping metal will have residues of metal and slag left on their linings after they have been in use. These residues must be removed before the crucibles can be used again.

Norwegian Patent No. 170905 describes a cleaning machine for removing slag and metal residues from tapping crucibles for molten metal. The cleaning machine comprises a frame on which is arranged a carriage or slide movable in an upwardly inclined direction, which is provided with a milling or cutting tool, and a holder for tapping crucibles arranged in connection with the frame and which is tiltably arranged and can be tilted from a lower position, in which a tapping crucible can be placed on or taken off the holder, to an upper, inclined position in which the axis of the tapping crucible is coincident with the axis of the cutting tool.

A disadvantage of known cleaning machines of this type is that the frame or carriage that moves the crucible from the floor up to the milling position requires that the emptying of residual liquid metal in the tapping crucible, which must take place prior to the cleaning/milling operation, should take place at a certain height (face height) above the floor. During the emptying of residual metal, there is often some splashing and spilling of liquid metal which may damage components of the cleaning machine and injure people standing in the vicinity thereof. Splashes of liquid metal often end up in an area containing hydraulic components and piping and wiring. Earlier designs also call for a mechanism which can swing the container containing liquid metal to the side and into the operator area when the crucible is to be advanced to the milling operation.

It is an object of the present invention to provide a cleaning machine which is safer to use than earlier cleaning machines of the same type.

Another object of the present invention is that it is to be easier and less expensive to produce and maintain. It is also an object that the design should be capable of being more readily adapted to different types of premises and crucible sizes as these often vary from smelting plant to smelting plant.

The invention relates to a cleaning device which comprises a crucible manipulator constructed as a travelling crane which can lift, advance and rotate tapping crucibles. The floor can be made smooth and there is no need for a track which must be kept clean in order to function satisfactorily. Jamming dangers are reduced. The use of a travelling crane allows most of the hydraulic components and electrocomponents as well as pipes and cabling to be lifted up and away from the area which is exposed to metal splashes. This will protect components which are prone to fire damage. The residual metal in the tapping crucibles can be emptied into containers standing on the floor. The container containing residual metal may have a fixed position on the floor and need not be moved more than absolutely necessary, i.e., when it is full and must be driven away by forklift. Thus, it is possible to avoid the situation in which the container containing residual liquid metal has to stand at face height and has to be tilted out to the side and into the operator area between each milling operation, which has been necessary in connection with some earlier solutions. Since the rotation of the crucible takes place around its centre of gravity and not along a path with its centre outside the crucible, the emptying of residual metal is effected in a more controlled manner and will not be as sensitive to varying amounts of residual metal as in earlier solutions. The construction of the lifting cage so that the crucible can be manipulated with pure translatory movements or rotational movements, as described above, will result in a simpler mechanical construction which can more easily be adapted to different constructional heights and automation of the milling operation.

Another aspect of the invention comprises that cutting teeth can also be used which have stud elements that can rotate as they become worn. Stud elements of this type have been well tested in other connections such as in road graders, but have not been used in the cleaning of tapping crucibles. The advantage of cutting teeth of this type is that they are self -rotating during milling or cutting, resulting in the stud being worn more evenly and the capacity being better utilised. The cutting teeth are produced in large quantities for purposes other than crucible cleaning. Thus, these cutting teeth are far less expensive than the specially cutting teeth that are used in some existing solutions for crucible cleaning.

The rotatable stud elements also have a simpler attachment (split sleeve) and can be replaced more easily than in earlier solutions which require screws and nuts. The cutting teeth can also be replaced "more individually" than in previous solutions if they are damaged because a cutting tooth is composed of several stud elements. Each stud element can be replaced individually.

According to the invention, a cleaning device for removing slag and metal residues from tapping crucibles for molten metal has been arrived at, wherein the cleaning device comprises a frame on which is arranged a movable slide that is provided with a rotatable cutting tool of the full profile type equipped with a tool head, characterised in that on the frame there is arranged a travelling crane with a lifting cage for tapping crucibles which can collect, lift and rotate the tapping crucible from a lower position on the floor with its opening in a horizontal plane, to an upper position for cleaning in which the opening is in a plane that is at 90° to the axis of the cutting tool and in which the axis of the tapping crucible is coincident with the cutting tool axis, and wherein the cutting tool axis is essentially coincident with the horizontal plane.

The invention will now be described in more detail with reference to the attached drawings, wherein:

Fig. 1 is a side view of a cleaning device according to the invention. Fig. 2 is a front view of the tool head.

Fig. 3 is a front view of an example of an embodiment of a cutting tooth, which can be used for cleaning the bottom of the crucible.

Fig. 4 is a side view of the same embodiment of the cutting tooth as that shown in Fig.

3.

The cleaning device 1 according to the invention is shown in Fig. 1 and comprises three main components: frame 2, a carriage or slide 3 with a cutting tool 4, and a travelling crane 5 with a specially designed lifting cage 6 for tapping crucibles 7.

The cutting tool 4 is arranged on a shaft 8 which is supported in the slide 3. The shaft 8 is driven by a motor 9. The slide 3 is movably arranged in the frame 2 by means of horizontal guide rolls 10 and vertical guide rolls 11 at each side of the frame 2.

A hydraulic piston/cylinder assembly 12 provides the movement of the slide 3 in both directions of travel. The actual cutting tool 4 consists of a cylindrical pipe 13 on which there is provided a tool head 14 for attachment of cutting teeth 15 and a helical flat steel 16 for guiding slag residues backwards along the cutting tool 4. The cutting tool 4 is rotated by the motor which is located at the end of the movable frame 2.

The cleaning device comprises a crucible manipulator constructed as a travelling crane 5. The travelling crane 5 has a specially designed lifting cage 6 which grips the crucible 7 from a position on the floor with its opening in the horizontal plane (0°) and holds it in position by means of hydraulically operated locks which are mounted on the lifting cage 6. This is the starting position for the cleaning sequence.

A tapping crucible 7 is placed in a fixed position, either by a special vehicle for crucibles or by a forklift. From this position, the crucible 7 is collected by the crucible manipulator, which locks it in place, lifts and rotates the crucible 7 for emptying any residual liquid metal (70°-100°) into a suitable chill mould 17. The tapping crucible 7 is hot, and emptying residual liquid metal takes place by moving the crucible across the edge of the chill mould 17 and rotating it so that the metal is emptied in a controlled manner.

Furthermore, the crucible 7 is rotated back so that its opening is in a plane that is 90 degrees in relation to the axis 18 of the cutting tool 8 and then lifts the crucible 7 into a position in which the axis 19 of the crucible 7 is coincident with the cutting tool axis 18. This is the milling/cleaning position.

The cutting tool axis 18 is preferably in a range of 0°- 15° relative to the horizontal plane, more preferably in a range of 0°-8° relative to the horizontal plane, and most preferably essentially coincident with the horizontal plane.

When the crucible 7 has reached the milling position, separate locks 20, mounted in the frame 2, grip the crucible flange and lock it in place before the milling operation commences. The cutting tool 4 is now made to rotate, and the slide is advanced by a hydraulic piston/cylinder assembly 12 in the direction of the crucible 7.

The tool head 14 comprises cutting teeth 15a mounted on the forward side of the tool head along the periphery of the tool head 14 and cutting teeeth 15b mounted on the tool head within the periphery and spaced from the periphery. Cutting teeth 15a will clean the side walls of the crucible 7 whilst the cutting teeth 15b will clean the bottom of the crucible 7. Fig. 2 is a front view of an advantageous embodiment of the tool head 14 with mounted cutting teeth 15a and 15b. In the first part of the milling sequence, slag and metal residues will be removed from the sides by cutting teeth 15a as the tool head is moved inwards. At the end of the sequence, the bottom is cleaned by the cutting teeth 15b which are mounted on the front of the cutting tool. The milling sequence is terminated in that the cutting tool is drawn right out, the slide 3 is parked in the rear position and the locks 20 are opened so that the crucible 7 can be moved freely again for complete emptying of slag residues (180 degrees) into suitable skips 21. When this operation has been carried out, the crucible 7 is moved back to the cleaning sequence starting position, the hydraulically operated locks 20 are opened, and the travelling crane 5 with lifting cage 6 is moved back. The crucible 7 is now ready for collection.

The same skips 21 catch any slag residues which come out during the actual milling operation. The skips 21 for slag residues and the chill mould 17 for the residual metal are replaced and emptied by forklift as required.

An attempt has been made to find an optimum number of cutting teeth 15 for carrying out an efficient and economical cutting operation. The use of too many cutting teeth 15 results in too little surface pressure (feed pressure) per cutting tooth, and an inefficient milling. The use of too few cutting teeth 15 results in excessive tool wear. An attempt has also been made to allow optimal transport of material backwards along the tool head through three sectors 22 which run right out to the periphery of the tool head.

Figure 2 shows another aspect of the invention which comprises that cutting teeth 15 can be used which comprise one or more stud elements 23 that can rotate as they become worn. Stud elements 23 of this type are self -rotating during milling, resulting in the stud elements 23 being worn more evenly and the capacity being better utilised. The stud elements 23 are produced in large quantities for purposes other than crucible cleaning. Thus, these stud elements 23 are inexpensive. The rotatable stud elements 23 also have a simpler attachment (split sleeve) and can be replaced more easily than in earlier solutions which require screws and nuts.

Figure 4 is a side view the cutting tooth 15 with the stud elements.

Claims

P a t e n t c l a i m s

1.

A cleaning device (1) for removing slag and metal residues from tapping crucibles (7) for molten metal, comprising a frame (2) on which there is arranged a movable slide (3) that is provided with a rotatable cutting tool (4) of the full profile type equipped with a tool head (14), characterised in that on the frame (2) there is arranged a travelling crane (5) with a lifting cage (6) for tapping crucibles (7) which can collect, lift and tilt the tapping crucible (7) from a lower position with its opening in a horizontal plane to an upper position for cleaning in which the opening is in a plane that is at 90° to the cutting tool axis (18) and in which the tapping crucible axis (19) is coincident with the cutting tool axis (18), and that the cutting tool axis (18) is essentially coincident with the horizontal plane.

2.

A cleaning device according to claim 1, characterised in that the cutting tool (4) immediately behind the tool head (14) is made in the form of a cylindrical pipe (13) which is provided with a helical flat steel (16) for propelling or guiding slag residues back along the cutting tool (4).

3.

A cleaning device according to claims 1 and 2, characterised in that the tool head (14) is provided with first cutting teeth (15a) which are spaced apart along the periphery of the tool head, and second cutting teeth (15b) which are spaced apart in a radial direction, in such manner that the second cutting teeth (15b) are spaced apart along three radial lines at an angle to each other of 120°, and that the tool head (14) has three sectors (22) which extend right out to the periphery of the tool head (14).

4.

A cleaning device according to the preceding claims, characterised in that the cutting teeth (15) comprise rotatable stud elements (23).