Field of Technology

Folding of foldable material; mineral wool folding; textile folding.

Technical Problem

Technical problem to be solved by present invention are problems caused by air trapped during folding of foldable material such as mineral wool or other similar material (including textile material), wherein said air escapes and disrupts folding of said foldable material, including and not limited to rupturing said foldable material. Foldable material in mineral wool industry is the so called primary layer that comes out of collecting chamber that collects mineral fibers produced on spinning machine.

State of the Art

There are number of machines aimed at folding of foldable material to achieve multi layered continues mat. This divides are described in for example in EP 0528348, WO 88/03121, WO 88/03509, EP 0630998 Primary layer continuously enters into pendulum device which performs swinging motion and therefore lay the primary layer into multiple layers called secondary layer. Width of primary layer is typically between 1.5 m and 4 m and its travel speed is typically between 80 m/min and 160 m/min. Secondary layer travels in directional that is perpendicular to primary layer travel direction. Secondary layer travels continuously and its speed defines number of primary layers in it. With high number of primary layers more homogenous secondary layer can be achieved. Width of secondary layer is typically between 1.2 and 2.6 m.

In mineral wool production process it is desirable to produce as thin primary layer as possible and lay as many layers as possible for given secondary layer area density. If surface area of secondary layer is to be for example q _sec = 5 kg/m ² that means that primary layer area density is:

_ Qsec qP ^ri - - f where N is number of primary layer in secondary layer. Area density of primary layer for secondary layer containing for example 6, 10 or 14 are 833 g/m ² , 500 g/m ² and 357 g/m ² . Good quality primary layer is considered to have area density typicality below 350 g/m ² preferably below 300 g/m ² and even more preferably below 250 g/m ² .

It is unpractical to have primary layer wider than 4m and therefore to achieve high capacity production for example 14 t/h and maintain low primary layer density of about 300 g/m ² primary layer speed has to be 194 m/min. This high speed of primary layer causes difficulties in laying process. If for example primary layer is to be laid to form secondary layer 2 m wide it means that each layer is to be laid in every 0.62 s. When primary layer exits pendulum system it is subject to gravity forces and air drag forces. Air drag forces are caused by primary layer falling vertically and also by air streams caused by mechanical movement of pendulum device.

Ratio between gravity forces and air drag forces decreases with lowering primary layer area density. This is due to the fact that lower primary layer area density is subject to lower gravity forces and also and even more significantly due to high pendulum dynamics that causes air drag streams that interact with primary layer. It is obvious that gravity force on primary layer is in linear relationship with its area density

Fg OC ( p _ri and that air stream force is proportional to square of air stream velocity:

Fdrag ^pri

Mass inertia of primary layer is also proportional to its area density. That means that primary layer dynamic is more intense for low primary layer density for given air drag force. From this facts it is clear that the motion of low area density primary layer will be affected significantly by the air drag forces at high laying speeds. For example, Fig 1. shows side view of existing embodiment of pendulum device 1. Primary layer 2 is transported via feeding belt conveyor 3 between outer pendulum belt 4 and inner pendulum belt 5. Pendulum belts 4 and 5 are mounted on pendulum frame 6 that is supported on upper rotational joint 7. Pendulum frame 6 is driven by the link 8 and crankshaft 9 to perform pendulum motion of inner and outer belt conveyors 4 and 5. Primary layer 2 exits pendulum belts at point 10 which is located at the middle of the line defined by centers of lower roller 11 of outer belt conveyor 4 and lower roller 12 of inner belt conveyor 5. By pendulum conveyor belt swing direction 15 primary layer is laid down on secondary layer conveyor 13 and forms secondary layer 14.

After primary layer exits the pendulum belts at point 10, air is trapped between primary layer in falling phase 16 and already deposited primary layer 17. Airflow forms streamlines 18 in front of the pendulum. Some of the air passes through primary layer in falling phase 16 in form of streamlines 19. Above primary layer 16 air vortex 20 is formed.

In practice we never deal with ideal primary layer in terms of homogenous fiber distribution, mechanical properties, air resistance characteristic and so on. There will always be some areas with higher concentration of fibers. Airflow naturally passes through area of primary layer with least resistance which are the parts with minimum fibers accumulated in primary layer. This parts of primary layer are also mechanically weakest spots. This means that the maximum forces caused by the air flow 19 are applied on weakest areas of primary layer. This can further cause primary layer rupture that can lead in poor final product and efficiency. Vortex 20 is also the region of low pressure that causes slow falling of primary layer 16 which is a problem at high laying speeds.

Fig 2. Shows top view of pendulum device 1 with secondary layer conveyor 13 with secondary layer 14 moving in direction 22. Lower roller 11 and 12 of outer and inner pendulum conveyor belts 4 and 5 are moving in direction 15. Side air flow 21 is forced on both sides between primary layer in falling phase 16 and already laid primary layer 17. Description of New Invention:

Pendulum folder for foldable material folding solves problems caused by air trapped during folding of foldable material such as mineral wool or other similar material (including textile material), wherein said air escapes and disrupts folding of said foldable material, including and not limited to rupturing said foldable material by covering falling phase on the top by a pendulum belt, said belt preventing airflow through primary layer and thus preventing mechanical deformation of primary layer.

Further, with this new invention old pendulum devices can be upgraded to eliminate problem of air drag forces on primary layer and consequently increase laying speeds and by this quality of end product.

Foldable material travels from originating position (being, for example, mineral wool apparatus, or storage, or any other kind of fibrous material production machine or storage) toward folding position wherein said foldable material is folded to form plurality of layers one on top of another.

Said foldable material in continuous (or discontinuous) sheet form enters guiding means, said guiding means serving as pendulum folding said foldable material during pendulum swings. Guiding means in this particular embodiment are formed as part of two belts, each belt forming at least part of a loop, each belt having distance from another forming a channel through which said foldable material passes. Guiding means forms only part of said loops, namely part actually guiding said foldable material. Guiding means are comprised of entry part, exit part, and a channel between said entry part and said exit part. Normally, each of the belts would form a continuous loop but embodiments can be made wherein said belt forms only part of a loop. Advantage of having belt into continuous loop is reduction or limitation of drift between belt surface and foldable material surface.

Said guiding means is therefore formed of at least first part, said first part formed of at least part of first belt, and of second part, said second part formed of at least part of second belt. Said guiding means is capable of swinging in such a way that said entry part into said channel forms small or none movements compared to said exit part from said channel which makes substantial moves in periodic fashion. By having said moves, said foldable material exiting said channel is laid in layers following movements of said guiding means thereby being folded.

As said, said guiding means form part of each belt loop starting at entry part and ending at exit part. Following exit part, each of said belts form, in part, covering means for covering of said foldable material being folded. As said belts form both covering, and guiding means, by swinging, said covering means on one side follow closely formation of each layer while on the other side cover already existing layer or plurality thereof to be covered by new-forming layer. In effect, said covering means look as periodically moving cover with slit in the middle in which said foldable material enters folding area.

Each of said belts follows path through series of pulleys or guides designed in such a way that each of said belts is essentially taut thus forming a barrier for supporting of said foldable material when said belts form guiding means, and forming a barrier against reducing or redirecting said air flow when belts form covering means.

Said covering means is therefore formed of at least first part, said first part formed of at least part of first belt, and of second part, said second part formed of at least part of second belt.

Pendulum folder for foldable material folding comprising:

(a) at least two belts, the first belt, and the second belt;

(b) guiding means for guiding of said foldable material toward folding area, said guiding means formed of at least first part, said first part formed of at least part of said first belt, and of second part, said second part formed of at least part of said second belt;

(c) covering means for covering of said foldable material during folding; said covering means formed of at least first part, said first part formed of at least part of said first belt, and of second part, said second part formed of at least part of said second belt;

(d) said first belt forming both said first part of said guiding means and said first part of said covering means;

(e) said second belt forming both said second part of said guiding means and said second part of said covering means;

(f) said guiding means forming entry part, a channel, and exit part, said guiding means swinging essentially as pendulum with entry part swinging the least including not swinging and exit part swinging the most;

(g) said covering means moving in periodic fashion with said opening following movement of pendulum and thereby covering most of folding area.

Pendulum folder according to this invention further comprising said first belt and said second belt, both of said belts moveable wherein said first part of said guiding means and said second part of said guiding means move generally in same directions while forming part of said guiding means.

Pendulum folder according to this invention further comprising said first belt and said second belt, both of said belts moveable wherein said first part of said covering means and said second part of said covering means move generally in opposite directions while forming part of said covering means.

Pendulum folder according to this invention wherein said first part of said guiding means and said second part of said guiding means form a channel through which said foldable material passes.

Pendulum folder according to this invention wherein there is an opening transversely to direction of said foldable material moving, said opening formed between said first part of said covering means and said second part of said covering means, said foldable material passing through said opening to inter into folding area. Pendulum folder according to this invention wherein said foldable material is chosen from the group containing mineral wool, non-woven textile, woven textile, , rock wool, glass wool, slag in fibrous form, metal wool, material comprising fiber.

Method for folding of foldable material wherein said method is comprised of the following steps:

(a) guiding of foldable material from originating point chosen from the group containing mineral or glass wool production machine, , textile fiber production machine , any other kind of fibrous material storage toward folding area;

(b) passing of said foldable material through channel, said channel formed of first part of guiding means and second part of guiding means;

(c) passing of said foldable material through opening transversely to general direction of foldable material movement, said opening formed between first part of covering means and second part of covering means;

(d) folding of said foldable material by swinging motion of said guiding means;

(e) protecting in part of said foldable material by covering it with said covering means.

Figures as described below form part of these specifications, and show

1. Existing embodiment of pendulum device

2. Primary layer

3. Feeding belt conveyor

4. Outer pendulum belt conveyor

5. Inner pendulum belt conveyor

6. Pendulum frame

7. Upper pendulum rotational joint

8. Link

9. Crankshaft

10. Exit point of primary layer from pendulum belt

11. Outer belt conveyor lower roller

12. Inner belt conveyor lower roller Secondary layer conveyor Secondary layer Pendulum conveyor belt swing direction Primary layer in falling phase Primary layer deposited on secondary layer Streamlines of air in front of pendulum belts Streamlines of air passing through falling primary layer Vortex behind pendulum belt conveyors Side air flow Secondary layer moving direction First embodiment of pendulum device according to the invention First pendulum belt Second pendulum belt Drive roller of first pendulum belt Drive roller of second pendulum belt First belt compensation mechanism Second belt compensation mechanism First pendulum link Second pendulum link First deflecting roller of first pendulum belt Second deflecting roller of first pendulum belt Lower pendulum roller of first pendulum belt of third deflecting roller of first pendulum belt Forth deflecting roller of first pendulum belt First belt length compensation roller movable in vertical direction or fifth deflecting roller of first pendulum belt Sixth deflection roller of first pendulum belt Seventh deflection roller of first pendulum belt First deflecting roller of second pendulum belt Second deflecting roller of second pendulum belt Lower pendulum roller of second pendulum belt of third deflecting roller of second pendulum belt Forth deflecting roller of second pendulum belt Second belt length compensation roller movable in vertical direction or fifth deflecting roller of second pendulum belt Sixth deflection roller of second pendulum belt First rotational support of first pendulum link Second rotational support of first and second pendulum link Third rotational support of second pendulum link Pendulum carriage unit Belt length compensation link element between first and second belt compensation mechanism First deflection pulley for compensation link element Second deflection pulley for compensation link element First pendulum belt section covering secondary layer Second pendulum belt section covering secondary layer Horizontal movement of pendulum carriage unit Angle between horizontal plane and second pendulum belt covering secondary layer Angle between horizontal plane and first pendulum belt covering secondary layer Embodiment of pendulum device according to the invention with two vertically movable rollers in each belt compensation mechanism Second roller of first belt length compensation movable in vertical direction or sixth deflecting roller of first pendulum belt Second roller of second belt length compensation movable in vertical direction or sixth deflecting roller of second pendulum belt Belt length compensation link element between first and second length compensation roller of first belt length compensation mechanism Belt length compensation link element between first and second length compensation roller of second belt length compensation mechanism Second deflection pulley for compensation link element 60 Second deflection pulley for compensation link element 61 Fiber accumulation grid Primary layer loop at pendulum device discharge A. Point of separation of primary layer from accumulation grid to pendulum device primary layer feeding conveyor

B. Primary layer entrance point between first and second pendulum belt.

66. Pendulum device feeding conveyor

67. Horizontally movable belt deflection roller

68. Vertically movable tensioning roller

C. Point of reversing primary layer travel direction

Fig 3. Shows embodiment of the pendulum device 23 according to the invention in its right end position. Pendulum device 23 consists of first pendulum link 30 that is supported with first rotational support 45 and is connected to second pendulum link 31 with second rotational support 46. Second pendulum link 31 is further connected with rotational link 47 to pendulum carriage unit 48 performing horizontal movement 54.

First pendulum belt 24 is driven by drive roller 26 and travels around first belt deflecting rollers 32, 33, 34, 35, 36, 37, 38. Second pendulum belt 25 is driven by drive roller 27 and travel around second belt deflecting rollers 39, 40, 41, 42, 43, 44.

First pendulum belt 24 has first belt length compensation mechanism 28 with vertical movable belt deflecting roller 36. Second pendulum belt 25 has second belt length compensation mechanism 29 with vertical movable belt deflecting roller 43. Length compensation mechanisms 28 and 29 ensures sufficient belt tension regardless of primary layer exit point 10 of pendulum device 23.

By help of Fig 3 operation of subject of this invention is described in details.

After primary layer exits at point 10 primary layer in falling phase 16 is covered on the top by second pendulum belt 53 and which prevents airflow through primary layer and thus prevents mechanical deformation of primary layer. Already laid primary layer 17 is covered by first pendulum belt 52 that also prevents air drag forces on secondary layer. First belt length compensation rollers 36 in its lower position and second belt length compensation roller 43 in its upper position are connected with belt length compensation link element 49 (belt, chain, steel rope or similar) traveling around pulleys 50 and 51. When the primary layer exit point 10 moves to the left with velocity v roller 36 moves upward with velocity v/2 and roller 43 with velocity v/2 downward. This is achieved by belt length compensation link element 49 which lowers length compensation roller 43 by the same height as the compensation roller 36 moves upwards.

Horizontal plane and first pendulum belt covering secondary layer form an angle 56 and horizontal plane and second pendulum belt form an angle 55. Each of this angles is usually between -30° and +30° or preferably between -15° and +15° or more permeably between -5° and +5° along the entire stroke of the pendulum device.

Fig 4. Shows embodiment of the pendulum device 23 according to the invention in its center position. Pendulum carriage unit 48 is in the center position and the belt length compensation rollers 36 and 43 are in its middle vertical position.

Fig 5. Shows embodiment of the pendulum device 23 according to the invention in its left position. Pendulum carriage unit 48 is in the left position. First belt length compensation rollers 36 is in its upper position and second belt length compensation roller 43 is in its lower position. Direction 54 of pendulum carriage unit 48 is reversed.

Fig 6. Shows embodiment of the pendulum device 57 according to the invention with two vertically movable rollers in each belt compensation mechanism. The pendulum device 57 is in its right end position. Compensation roller 36 compensation roller 59 are in its lower position. Compensation roller 58 and compensation roller 43 are in its upper position. When the primary layer exit point 10 moves to the left with velocity v rollers 36 and 59 moves upward with velocity v/4 and rollers 58 and 43 with velocity v/4 downward. This is achieved by belt length compensation link elements 49, 60 and 61 which lowers length compensation rollers 58 and 43 by the same height as the compensation rollers 36 and moves 59 upwards. Translational velocity of belt length compensation rollers 36, 43, 58 and 59 in pendulum device embodiment 57 is half compared to translational velocity of belt length compensation rollers 36 and 43 in pendulum device embodiment 23. Translational kinetic energy of compensation rollers 36, 43, 58 and 59 in embodiment 57 is also half compared to translational kinetic energy of compensation rollers 36 and 43 in embodiment 23.

Translational kinetic energy of belt compensation rollers for pendulum device embodiment 23:

Translational kinetic energy of belt compensation rollers for pendulum device embodiment 57:

Embodiment 57 is therefore more suitable for dynamically more demanding laying processes.

Fig 7. Shows embodiment of the pendulum device 57 according to the invention with two vertically movable rollers in each belt compensation mechanism. The pendulum device 57 and compensation rollers 36, 43, 58 and 59 are in its center position.

Fig 8. Shows embodiment of the pendulum device 57 according to the invention with two vertically movable rollers in each belt compensation mechanism. The pendulum device 57 is in its left end position. Compensation roller 36 compensation roller 59 are in its upper position. Compensation roller 58 and compensation roller 43 are in its lower position.

Fig 9. Shows primary layer path from fiber accumulation grid 64 trough pendulum device 1 to secondary layer conveyor 13. Primary layer separates from accumulation grid at point A and enters between pendulum belts at point B. Travel direction between points A and B is always in the same direction. Technical problem of this embodiment is that primary layer velocity at point A and B is almost constant causing big primary layer loops 65 that trap a lot of air between primary layer in falling phase 16 and already laid primary layer 17. This further causes slow laying process and large air drag forces on primary layer in falling phase.

Fig 10. Shows embodiment according to the invention of pendulum device feeding conveyor 66 that receives primary layer from accumulation grid 64 at point A and convey in to the point C where it is dropped on first pendulum belt 24. The direction of primary layer travel is reversed at point C form left to right.

At primary layer discharge point C a horizontally movable roller 67 is mounted. To evenly tension the belt of feeding conveyor 66 tensioning roller 68 is vertically movable.

By this invention technical problem of large primary layer loop formation is eliminated. When the exit point 10 starts to decelerate to reach pendulum device end position, pendulum belts 24 and 25 also start decelerating accordingly. Excess of primary layer from accumulation grid is accumulated in primary layer path A-C-B by horizontal movement of roller 67 to the left. Excess of primary layer accumulated in primary layer path A-C-B is further laid by increasing the speed of pendulum belts 24 and 25 and movement of exit point 10 above primary layer speed at point A.