METHOD AND APPARATUS FOR VACUUM CLEANING A PILE OF MINERAL WOOL PLATES

Abstract: A method and an apparatus in the manufacture of mineral wool plates (3) by dividing a path of mineral wool (1) into plates of pieces each having the same length and width, said method and apparatus being useful in reducing the spreading of loose fibres and other particles from the edges of the mineral wool plates (3) by means of vacuum cleaning slots (10, 11, 12) or corresponding means exhausting air from the area adjacent the mineral wool surface so that loose fibres and other particles are brought with the air into the exhaust slot or slots, whereby a pile (8) of mineral wool plates (3) is formed, whereupon the vacuum cleaning slots (10, 11, 12) are moved over all four side edges of said pile (8), and whereby said side edges are preferably sprayed (13, 14, 15) with a dust binding substance, which is then dried (16, 17).

Description: The present invention relates to method an apparatus in the manufacture of mineral wool mats by dividing a continuous lenght of mineral wool mat into pieces having the same length and width, said method and apparatus being useful in reducing the spreading fibres and other particles from the edges of mineral wool mats by using suction slot apparatus or a corresponding means for exhausting air from the area adjacent the mineral wool surfaces so that loose fibres and other particles are brought with the air and into the exhaust slot or slots. When handling of mineral wool products large or small amounts of dust are formed, which dust includes, among other tings, fibres. It is a general aim in the work environement to minimize the amount of dust, including fibrous dust, to which the working persons are exposed, and the present invention is intended to solve this problem. The invention is based on studies of the mechanisms which cause origin of dust and also the mechanisms which can be used to prevent spreading of dust. These studies have shown that the air-borne dust which is produced when handling mineral wool mainly comprises thin, short mineral fibres. The studies also have shown that the air-borne fibres and other particles which are produces emanate from the surfaces of the mineral wool products. In the manufacture of mineral wool a melted mineralic material is being fibrated thereby forming a continuous length of mineral wool mat in one or several steps. The main part of the mineral wool mat is bound by means of a binder. The binder is added during the fibration process, and the binder is hardened in that the mineral wool mat is moved through a hardening furnace in which the mat also is given its final thickness. From the hardening furnace leaves a continous length of mineral wool mat which has a more or less solid shape and a fixed thickness. Said continous lenght of mineral wool mat is then divided into several pieces. Said continous lenght of mineral wool mat, once divided, being referred to simply as mineral wool mats. This is made in several operations. Practically without exception the edges are cut clean by means of edge saws and the continuous length of mineral wool mat is cut to pieces of predetermined lenght by means of a cutting machine. The cutting machine may be of guillotine type or may be formed with one or more rotating saw blades which are movable across the continuous lenght of mineral wool mat. In most cases the continuous lenght of mineral wool mat is also divided in the longitudinal direction by means of a partition machine so that the mat is divided into two or more narrow lenghts of mineral wool mats moving aside of each other. In some cases the mineral wool mat also is split into two or more parts in that one or more band saws make horizontal cuts in the mineral wool mat thereby splitting or stripping same into several narrow lenghts of mats on top of each other. Generally there are no serious problems in vacuum cleaning the upper surface and the bottom surface of the mineral wool mat for removing dust and loose fibres. The patent US-A-2,999,262 discloses a method for removing particles from various surfaces of a glass fibre material, whereby mats of glass fibre material are moved to a continuous column or stack, which is fed through a cleaning zone in which the individual glass fibre mats are separated, a high velocity stream or air is directed into the charge of glass fibre plates whereby dust particles are removed from the opposite main surfaces of the stacked mats and the dust partcles are received in chamber and to a collection and disposal point. Said known apparatus removed dust particles from the main surfaces of the glass fibre mats only, but not from cut or sawn side edges of mats which have piled on a continuously moving conveyor, and indeed not from all from all four side edges of rectangular mats. Also the edge surfaces which are formed when the edges are cut are easy to reach with a vacuum cleaning apparatus. On the contrary it is difficult to vacuum clean the partition cuts, and in particular the cross cuts, for the purpose of removing particles. It has been suggested that the different mats, which are formed when the continuous length of mineral wool mat is "partition divided", should be moved apart so that a vacuum cleaning apparatus can be introduced in the space thereby formed between the mats. Said method, however, has not really come into practical use. Irrespective how this problem is solved it can be stated that vacuum exhausting of dust and loose fibres from the cross cut extending perpendicularly to the moving direction of the mat causes much greater problems. Modern manufacturing lines for mineral wool operate at speeds of 25 m/min or more. In connection to the cross cutting the cut apart pieces are often accelerated and thereby the moving speed becomes still higher. It is very difficult to arrange an effective vacuum cleaning at such high speeds of surfaces which are perpendicular to the moving direction. The present invention is intended to solve the above mentioned problem, and this is done, in the first place, in that the mineral wool mats are put together to a pile of mats, whereupon suction slots or suction nozzles or similar apparatus are moved over all four sides of the pile. It is thereby possible to cause the suction slots to move in relation to a still standing pile, or to cause a pile to move past fixed mounted suction slots or similar apparatus. In order to improve the flexibility so that it is possible to treat mat piles of different size in the same apparatus the suction slots are preferably arranged in pairs so that two opposite sides of the pile are treated in a first step and thereafter the two remaining sides are treated in a second step, whereby the treatments in each step with are done with separate sets of suction slots. In order to bind in particular the fibres and other particles which are left in the mineral wool after the vacuum cleaning, but which still form a potention source of dust, the mineral wool surfaces which have been vacuum cleaned are preferably treated with a dust binding substance. The best total effect is obtained if both flat surfaces of the mineral wool mats to be piled are vacuum cleaned before being piles, and that said surfaces are eventually also treated similarly. In high efficiency plants it may be good have the mineral wool mats form a continuous pile which is then continuously moved past a stationary vacuum cleaning apparatus which vacuum cleans the edge surfaces of the mats. In this embodiment the mats are preferably turned up so that the pile is placed horizontally and the mineral wool mats consequently are standing vertically in the pile. In less efficient production plants it may, on the other hand, be preferred to form piles of mats comprising the predetermined number of mats that the final mineral wool mat package is to contain. In particular in available plants, in which there is no free floor space for additional installations it is preferred to have the pile of mats move vertically up and then, possibly after some side displacement, vertically down again. Thereby the vacuum cleaning of the edges and any eventual treatment with a dust binding substance is made during the vertical movement and, in an actual case, also during the side displacement. In this case an especially suitable method is to execute the vacuum cleaning while the pile is moving vertically upwards. Then the pile is moved sideways and then back vertically down to a place relatively close to the place from where the movement vertically upwards started. In this case a possible treatment of the mineral wool with a dust binding substance is preferably made while the pile is moving downwards. In some cases the local conditions may be such that the first vertical movement is more easily made in the direction downwards, whereupon the second vertical movement is made in the direction upwards. Now the invention is to be desribed more closely with reference to five principle figures, in which figure 1 diagrammatically shows a side view of an apparatus according to the invention. Figure 2 shows a detail of an alternative embodiment of the invention having an upwards-sideways-downwards moving vacuum cleaning function, and figures 3 and 4 show a couple of further alternative arrangements of an apparatus according to the invention. Figures 5 and 6 show more in detail two different arrangements for vacuum cleaning of loose fibres and particles from the edges of mineral wool mats. Figure 1 shows a continuous lenght of mineral wool mat 1 which is moved on a roll conveyor 2. The mineral wool mat 1 is cut into short pieces, named mats 3, by means of a cutting apparatus 4, which in figure 1 is symbolized by a guillotine blade 5 which is movable between two guide plates 6a and 6b and which is driven by an intermittently rotatable excenter apparatus 7. By means of a turning apparatus which is not shown in the drawing the mats 3 are turned to edge standing position by being turned 90°, whereby said mats form a horizontal, continuous pile 8 of edge standing mats. The pile 8 is moved with a speed which is matching the line speed by means of a roll conveyor 9. Vacuum cleaning slots or rays 10 are mounted at the two vertical sides of the pile for exhausting or sucking off dust and loose fibres from the vetical sides of the pile, and some distance downstream said rays 10 additional vacuum cleaning slots or rays 11, 12 are mounted for vacuum cleaning the top and bottom surfaces of the pile 8. After the four sides of the pile 8 have been vacuum cleaned a dust binding substance is sprayed onto the two vertical sides of the pile by means of a pair of nozzles rays 13, and then the top surface and the bottom surface are sprayed with a dust binding substance by means of nozzle rays 14 and 15 resp. The dust binding substance may for instance be a mineral oil diluted with some solvent. The dust binding substance is then dried in that the surfaces are exposed to infra rays as symbolized in figure 1 by the heating and radiation apparatus 16 and 17 at the upper side and the bottom side of the pile respectively. In practice, of course, the radiation apparatus are arranged so as to expose also the vertical sides of the pile to the radiation. After the dust binding substance has become dried the continuous pile 8 is broken up into such units 18 which are later to form a package and which are prosecuted on the roll conveyor 19. In figure 2 is shown how mineral wool mats 3 supplied on the roll conveyor 2 have been piled to a pile 8′ by means of a piling apparatus which is not shown in the drawing. When the pile 8′ is ready it is moved by the roll conveyor 9′ to a new position symbolized by the pile standing in the position 20. From this position the pile is moved vertically up past the suction nozzles 10 which vacuum clean the surfaces of the pile extending in the plane of the drawing, and suction nozzles 11 and 12 which vacuum clean the two further sides of the pile. After the vacuum cleaning process the pile 8′ is moved further upwards past the rays 13, 14 and 15 which apply a dust binding substance on the edge surfaces of the pile 8′. From the position marked with the arrow 21 the piles are moved horizontally to a position marked with the arrow 22, and from there the piles are moved downwards past the radiation apparatus 16 and 17 which provide a drying or evaporation of the dust binding substance which has been sprayed onto the pile surfaces. After having passed the radiation apparatus the piles are moved further down to a position marked with the arrow 23 and are then moved out or the apparatus by the roll conveyor 19′. Figure 3 illustrates another method of executing the invention. The drawing basically shows a pile 8″ av mineral wool mats which is moved in the direction along the arrow 24 in between two suction slots 25 and 26 which vacuum clean the edge surfaces of the pile 8″ which are parallel to moving direction. The pile 8″ is then moved on to the position marked by the arrow 27. From this position the pile is moved at right angle in the direction of the arrow 28, past suction slots 29 and 30 which vacuum clean the two forther surfaces of the pile 8″. After the pile has been vacuum cleaned it is moved past the two nozzle rays 31 and 32 which spray a dust binding substance onto the edge surfaces which have just been vacuum cleaned. The pile is then moved on to the position marked with the arrow 33. From this position the pile is moved at right angle in direction marked by the arrow 34, past two nozzle rays 35 and 36 resp., which cover the two further edge surfaces with a dust bindning substance. The pile is further moved past a first radiation apparatus 37, 38, in which the dust binding substance is dried or evaporated, for instance by means of infra radiation, and as far as to the position marked by the arrow 39. From this position the pile is moved at right angle, marked by the arrow 40, past a second set of radiation apparatus 41 and 42, which dry or evaporate the dust binding substance on the two further sides of the pile. The pile is then moved in the same direction as far as to the position marked with the arrow 43 and then once again at right angle as marked with the arrow 44 and into the plant. Figure 4 shows a corresponding apparatus, in which the changings of moving directions provided for in the arrangement according to figure 3 are substituted by rotations of the pile. In figure 4 reference numeral 8″′ symbolizes the row of incoming piles. The pile is moved following the arrow 45 past the vacuum cleaning slots 25′ and 26′, which vacuum clean the longitudinal, vertical surfaces. In position 46 the pile is rotated 90° and is moved on in the direction of the arrow 47 past the vacuum cleaning slots 29′ and 30′, which vacuum clean the two further edge surfaces of the pile. Then the pile is moved on in the direction of the arrow 48 past the two nozzle rays 31′ and 32′ resp. which cover the said vacuum cleaned surfaces with a dust bindning substance which is then dried by a first set of radiation apparatus 37′ and 38′. In the position marked with the arrow 49 the pile is once again rotated 90° and is then allowed to pass the nozzle rays 35′ and 36′ which cover the two further edge surfaces of the pile with a dust binding substance which is then dried by a second set of radiation apparatus 41′ and 42′. Figur 5 shows a cross section through an exhaust slot means 50a for mechanically treating and exhausting of loose fibres and particles from the edge surfaces of a pile 8 of mineral wool mats. The exhaust slot means 50a comprises a cylindric brush 51 rotating in the opposite direction than moving direction of the mineral wool piles and which brushes up loose fibres from the surface. Air is at the same time sucked into the exhaust slot over the narrow air slot which is formed at least on the rear side of the exhaust slot as marked with the arrow 52. The loosened fibres and particles are then exhausted through a not illustrated exhaust pipe of the exhaust slot means 50a. Fibres and particles can easily stick to the brush and for removing same it is possible to have the brush rotate against a plate 53 mounted at or adjacent the upper side of the brush and which plate releases fibres and particles which have become stuck to the brush. Figure 6 shows an alternative exhaust slot means 50b for releasing or lifting off and exhausting loose fibres and particles from the edge surfaces of a pile 8 of mineral wool mats. In this case the exhaust slot means 50b comprises a blowing box 54 which directs a flow of air 55 obliquely downwards to the edge surface of the pile 8 and which thereby releases and whirls up loose fibres and particles. Also in this case the exhaust slot means 50b is connected to a not illustrated exhaust pipe, which exhausts such loose fibres and particles together with the air which is introduced through the this air slot at the rear side of the exhaust slot means as indicated with the arrow 56. It is also possible to combine the apparatus according to figure 5 and figure 6 in the same unit, whereby said unit will operate both by blowing action and by brush action.

Claims: Method in the manufacture wool mats (3) in which a continuous lenght of mineral wool mat (1) is divided into pieces each having the same lenght and width, and which method reduces the spreading of fibres and other particles from the edges of the mineral wool mats (3) by means of vacuum cleaning slots (10, 11 , 12; 25, 26, 29, 30; 25′, 26′, 29′, 30′; 50a; 50b) or corresponding means which exhaust air from the area adjacent the mineral wool surface so that loose fibres and other particles are brought with the air into the vacuum cleaning slot or slots, characterized in first forming a pile (8; 8′; 8″′) of the mineral wool mats (3), and when then moving the vacuum cleaning slot or slots (10, 11, 12; 25, 26, 29, 30; 25′, 26′, 29′, 30′; 50a; 50b) or said similar means over all four sides of the pile (8; 8′; 8″′). Method according to claim 1, characterized in that the vacuum cleaning slots (10, 11, 12; 25, 26, 29, 30; 25′, 26′, 29′, 30′) are arranged so that a first set of two opposed sides are vacuum cleaned and then the second set of two opposed sides are vacuum cleaned. Method according to claim 1 or 2, characterized in that the edge surfaces of the piles (8) of mineral wool mats are worked on, for instance mechanically (by means of a brush 51) or by air jet blowing (from a blower box 54) in connection to the vacuum cleaning. Method according to claim 1, 2 or 3, characterized in that the four sides of the pile (8, 8′, 8″′) are treated with a dust binding substance after having been vacuum cleaned. Method according to claim 1-4, characterized in that the two main surfaces of the mineral wool mat (1) are vacuum cleaned and eventuallty also treated with a dust binding substance in advance of piling the mineral wool mats and preferably also in advance of dividing (4-7) the continuous length of mineral wool mat (1) into separate mineral wool mats (3). Method according to any of claims 1-5, characterized in that the pile (8, 8′, 8″′) is formed in that several mineral wool mats (3) are moved together to form an integral pile, and in that said pile is moved past a stationary vacuum cleaning slot means (10, 11, 12; 25, 26, 29, 30; 25′, 26′, 29′, 30′; 50a; 50b). Method according to any of claims 1-5, characterized in forming free standing piles (8, 8′, 8″, 8″′) with the plates (3) positioned horizontally and preferably comprising the number of plates intended to form a package, and in then moving said piles past the vacuum cleaning slots. Method according to any of claims 1-5, characterized in that the mats (3) which have been cut out are turned to edge standing positions and are moved past the vacuum cleaning slots (e.g. 10, 11, 12) for exhausting dust from all four side edges, whereupon the mats are moved past rays of nozzles (e.g. 13, 14, 15) for application of a dust binding substance on all four side edges, and finally past one or more radiation apparatus (e.g. 16, 17) for drying the dust binding substance on all four side edges, whereupon separate, free standing piles (8) of a number of edge standing mineral wool mats (3) are formed in that the said number of mats (3) are turned back to a horizontal position and are moved out of the manufacturing line. Apparatus for executing the method according to any of the preceding claims included in a manufacturing line for the manufacture of a continuous lenght of a mineral wool mat (1) and having means (4-7) for dividing said continuous length of mineral wool mat (1) into separate mineral wool mats (3) each having the same length and width, said apparatus reducing the releasing of fibres and other particles from the edges of the mineral wool mats (3), characterized in that the apparatus comprises means for successively combining a number of mineral wool mats (3) to form separate mat piles (8, 8′, 8″, 8″′), means (10, 11, 12; 25, 26, 29, 30; 25′, 26′, 29′, 30′; 50a; 50b) for vacuum removing of dust, particles and loose fibres from all four side edges of the mineral wool mats (3), means (13, 14, 15; 31, 32, 35, 36; 31′, 32′, 35′, 36′) for applying a dust binding substance on the same four side edges of the mineral wool mats (3), and means 16, 17; 37, 38, 41; 38′, 41′, 42′) for drying the dust binding substance on the said four side edges. Apparatus according to claim 9, characterized in that it comprises means for turning up the cut out mineral wool mats (3) to edge standing positions before the vacuum cleaning, the application of the dust binding substance and the drying of the dust binding substance, and for folding down the said mats (3) to lying positions after the said treatment, and for forming the separate free standing mat piles (8, 8′, 8″, 8″′). Apparatus according to claim 9, characterized in that it comprises means for moving the piles (8′) a) upward -sideways - downwards, or b) downwards - sideways- upwards, or c) straight forward - sideways in one direction - straight forward - sideways in the opposite direction with respect to the first mentioned direction, or d) in a straight path while rotating the pile 90° - for advancing rotated 90° - for rotation back to the original position said movement being performed while successively performing the dust vacuum cleaning, the application of the dust binding substance and the drying of said dust binding substance. Apparatus according to any of claims 9-11, characterized in that it comprises means for treating the edge surfaces of the piles (8) of mineral wool mats mechanically by means of a rotatable brush (51) or by blowing a jet of air (54, 55) onto the mineral wool mats, or by a combination of said two methods.

Inventors: OEHBERG, INGEMAR, Öhberg, Ingemar
Applicants: ROCKWOOL AKTIEBOLAGET
Application year: 1989
Main classification: B08B5
IPC codes: D04H1, C04B41, C03B37, C04B38