DE2330195A1 - Paper, cardboard etc. web cutting - uses pressurised gas jet directed for short periods on web width transversely to its moving direction - Google Patents

Abstract

When it is desired to separate a continuous length of paper etc. web, when processing takes place at high speeds, a concentrated gas jet is directed at right angles to the paper surface, pref. close to a perforation line against the tensioned web. The gas jet pressure may be 7-15 atm. The tensioned web is guided over a support surface with a transverse slit coupled to compressed air line via a valve. The support surface may be formed by a cylinder jacket.

Description

DR. HEINZ FEDER DR. WOLF-D. FEATHER

CA Γ EN TA ^ vVAl (Η
Dusseldorf

File 73-10 / 20-02 June 12, 1973 WF / Wi

Hobema Maschinenfabrik Hermann H. Raths, 4 Düsseldorf, Worringer Str. 59

Method for knocking off a web of paper, cellulose or the like, and device to carry out the procedure.

The invention relates to a method for knocking off a web of paper, cellulose or the like.

In paper processing, the problem often arises that a web is unwound from a larger supply roll a processing device, for example a perforation »station, passed through and finally in individual longer ones Sections must be wound on cores. Here, the path must each time a certain predetermined section is wound on a core, be severed so that the finished winding can be removed from the device and a new one Core can be placed on which the next section of the web is to be wound. This cutting of the web in the transverse direction, the so-called "knocking off", has hitherto been used in particular in the case of webs provided with a transverse perforation carried out with so-called knockdown combs, which were actuated, for example, with compressed air and each controlled in this way had to be that they hit the track at a certain moment, and if possible so that they hit the track just occurred at one of the perforation lines, so that the web was severed at this point.

In the modern paper processing plants running at very high web speeds, however, this method has proven itself

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of knocking off the web proved to be disadvantageous because of certain speeds from a clean tee and especially a precise meeting of the perforation lines is not more is easily possible.

The object of the invention is to provide a method for knocking off a web of paper, cellulose or the like create, with which an exact control of the tee is possible even at high web speeds and a cleaner Tee of the web is received.

According to the invention, this is done in that a sharply focused gas jet generated under high pressure is briefly directed essentially perpendicularly onto the surface of the web along a line running transversely to the web against the tensioned web. It has been shown gef that with this method, very good results are achieved and the web can be cut off neatly at any desired location. In the case of webs which are provided with perforation lines running transversely to the web, it is particularly advantageous if the gas jet impinges on the web at or in the immediate vicinity of a perforation line. The web then tears off at the perforation line.

The pressure required to generate this gas pulse depends on the requirements of the individual case and is in particular on the type of material processed, its thickness and whether the material has perforation lines depends on. It has proven to be useful if the gas jet is at a pressure of 7 to 15 atmospheres, depending on the type of the material is generated. The exact conditions regarding the generating pressure, the pulse duration and the concentration of the gas jet can easily be determined for each practical case by means of simple experiments.

The invention also relates to a device for

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Implementation of the method according to the invention. According to the invention this device has a support surface over which the tensioned web is guided, the bearing surface a transverse has a slot extending to the direction of movement of the web and which is connected to a compressed air line via a valve stands. It is particularly useful when strips with a transverse perforation are to be knocked off, Proven to be useful when the support surface is the lateral surface a roller around which the web is guided, the valve after a predetermined number of revolutions the roller is controlled so that a jet of compressed air exits under high pressure from the slot and knocks off the web. With this embodiment, a particularly precise control of the knockdown process is possible, so that the path is always accurate is hit at a perforation line by the compressed air jet.

In a particularly advantageous embodiment of the invention Device is the valve chamber as extending parallel to the longitudinal direction of the slot Channel formed in which a movable bar extending over the entire length of the channel is arranged as a valve cone which rests sealingly against the inner end of the slot in the closed position of the valve. That way it is possible to simultaneously open or close the slot over the entire width of the web with the help of a single valve.

It has also proven to be particularly advantageous if the valve chamber has at least one additional chamber each at least one connecting channel is connected, wherein in the closed position of the valve, the compressed air line via a check valve is connected to the additional chamber, while the bar is in the open position of the valve sealingly applies to the end of the compressed air line and the

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Additional chambers are in communication with the slot. The additional chambers are therefore first used via the compressed air line pressurized and when the valve is opened, a short pressure surge occurs from the additional chambers, whereby the actual compressed air line is tightly closed. This has the advantage that the high pressure in the compressed air line can be constantly maintained and the individual compressed air impulses by controlling the valve from the additional chambers take place out.

The valve can also be constructed in the manner of a quick exhaust valve, with the connecting channels opposite the side of the bar facing away from the end of the compressed air line open into the valve chamber and the check valve is formed by elastic sealing lips arranged on the strip, which allow the inflow from the compressed air line releasing to the auxiliary chamber under pressure, apply to the walls of the valve chamber. Such quick- Ventilation valves are known per se for installation in pipelines. Surprisingly, this principle can also be used apply to a valve in which the valve cone is designed as an elongated bar, as in the present case. In this embodiment, the valve is controlled by venting the compressed air line. According to the The arrangement of the connecting channels is when the compressed air line is ventilated through the bar in the additional chambers The remaining pressure is immediately pressed into the open position of the valve and the compressed air escapes from the additional chambers through the slot, as will be described in more detail below with reference to an exemplary embodiment. With this device particularly short opening times of the valve can be achieved and thus particularly short-term impulses.

In another embodiment of the device according to the invention, the valve chamber is provided with several Zvsetzk.ammern

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Connecting channels connected and the additional chambers are In The opening direction of the valve is seen behind the valve chamber arranged * A displaceable piston is arranged in each additional chamber, which seals through an opening the wall between the valve chamber and the respective additional chamber guided plunger is connected to the bar, wherein the The piston is under the force of a spring acting in the closing direction of the valve and the connecting channels each have the Seen in the opening direction of the valve behind the bar of the valve chamber with the space in front of the piston connect the lying space of the additional chamber. Here, the sum of the front surfaces of the pistons should be greater than that rear surface of the bar · As described in more detail below with reference to the exemplary embodiment, has such a Valve has the property that with a slow pressure increase in the supply line, at a certain minimum pressure, very quickly ' to open. In this way, a short-term | Compressed air pulse can be generated. {

Various variants are also possible in this embodiment. So the piston on the side walls of the additional: the chamber over a sealing ring. The piston can j but also with the side walls of the additional chamber via a be connected sealing membrane. To make the opening pressure of the valve adjustable, the bias of the Spring adjustable be changeable.

In all of the illustrated embodiments, it has proven to be very advantageous if the slot is from the inside narrowed to the outside like a nozzle.

In the following, exemplary embodiments are given with reference to the accompanying figures explained in more detail for the device according to the invention, j

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Figure 1 shows a perspective schematic representation an apparatus according to the invention.

FIG. 2 shows, in an enlarged illustration, a section through

the device of Figure 1 in a plane perpendicular to; Roller axis
FIGS. 3 and 4 show, in an enlarged partial section, other embodiments of the device according to the invention.

j In the figures, only those essential for the invention are in each case borrowed parts of a paper processing machine shown. As can be seen from Figure 1, the web 1 runs over a roller 2} the roller 2 can be part of a larger device, for example a perforating and winding machine. The roller 2 rotatable about its axis S has, as can also be seen from FIG Roller axis S running slot 3 · Through this slot 3 can emerge a sharply focused gas jet, the so it is controllable that it is effective for a short time and precisely when the roller is approximately in the position shown in FIG Position. The web is then cut off at the location of the slot. Is the web with in the transverse direction provided extending perforation lines, the movement can be controlled in a manner known per se so that the Slot 3 in the position shown in each case coincides with a perforation line of the web.

Details of the device controlling the gas jet are shown in FIG. The one in the outer surface of the roller 2 arranged slot 3 lies radially to the roll axis S and widens inward. It flows at its inner end into the upper part of a chamber 4, with which it is connected over its entire length. The lower part of the chamber 4 is Connected to a compressed air line 6 via a supply duct 7. The upper part of the K & nuner 4 is also via connecting channels 9a and 9b connected to additional chambers 8a and 8b. In the canoe 4 is a freely movable bar 5

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made of sealing material, for example hard rubber, arranged, which extends over the entire length of the chamber 4 and extends optionally on the upper wall, into which the slot 3 opens, or on the lower wall, into which the feed channel 7 opens, can create a seal. The strip 5 also has sealing lips 5a and 5b on its lateral edges, which lie against the side walls of the chamber 4. The sealing lips 5a and 5b are arranged in such a way that they allow the passage release the air from the supply channel 7 through the lower part of the chamber 4 into the upper part of the chamber 4 under pressure, but prevent the air from flowing back into the lower part of the chamber 4, in which it is prevented by the acting pressure be pressed against the side walls with a controlled pressure drop in the feed channel 7. The sealing lips 5a, 5b thus act as a check valve.

The device described above acts as a quick exhaust valve in the following way:

If the compressed air supply line 6 is under high pressure, for example 7 to 15 atm is set, the lower part of the chamber 4 fills with air, and the bar 5 is firmly attached to the upper Wall of the chamber 4 pressed and closes the inner end of the slot 3. Furthermore, the air can at the sealing lips 5a and 5b pass into the two additional chambers 8a and 8b, so that these are under the same air pressure as the supply line. A backflow of the air from the additional chambers 8a and 8b into the compressed air line is prevented by the Sealing lips 5a and 5b prevented. If now the compressed air line 6 is vented, the bar 5 is through the into the Additional chambers 8a and 8b prevailing overpressure immediately pressed down and lies sealingly on the inner end of the supply channel 7. Xn this moment the compressed air stored in the additional chambers 8a and 8b can through the slot 3 escape to the outside. As the movement of the

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Bar 5 is only caused by the pressure difference between the upper part and the lower part of the chamber and none at all additional mechanical control devices are necessary, the movement is extremely rapid, so that the pressure in the enlarged inner part of the slot 3 increases very quickly and a sharply focused air pulse from the Slot 3 exits. It is not necessary to vent the compressed air supply line 6 down to atmospheric pressure take place, but the movement of the bar takes place automatically at a certain through the technical data of the device conditional pressure difference.

The ventilation of the compressed air line 6 and its exact Control is carried out by devices known per se, which are not specifically shown.

In an embodiment of the device according to FIGS. 1 and 2 with a length of the slot 3 of 2.7 m and a working pressure of 15 atmospheres, outflow times of 1.1 ms were measured. The amount of air flowed out per pulse was 0.0015 m ³ .

In Figure 3, another valve arrangement for controlling the gas jet knocking off the web is shown in partial section. The web 11 is guided over a support body 12 which, as in the embodiment described above, it can also be part of a roller. In the surface of the support body there is an exit slot 13 running transversely to the web 11. The exit slot which widens inwards

13 opens into a chamber 14 which is connected to the slot over its entire length. The chamber 14 is on the one hand connected directly to the compressed air line 16, on the other hand via a number of connecting channels 19 with a row of additional chambers 18. The additional chambers 18 are seen from the exit end of the slot 13 behind the chamber

14 (arranged under the chamber 141 in FIG. 3. In the chamber

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14, a movable bar 15 running over its entire length is arranged, which has a wedge-shaped shaped attachment 15a, on both sides of which sealing strands 15b are arranged. The bar 15 can so lay on the upper wall of the Kanuner 14 that the slot 13 is closed. The attachment 15a is seated here in the widened inner part of the slot 13 and the sealing strands 15b lie against the upper wall of the Kanuner 14. In this position, the outlet slot 13 is sealed off. Slidable pistons 20 are in the additional chambers 18 arranged. The pistons 20 are via tappets 17, which seal through the wall between the chamber 14 and the additional chambers are passed through, firmly connected to the bar 15. The upper part of the additional chambers 18 is against the lower part of the Additional chambers 18 sealed off, namely in the embodiment shown in Figure 3 by one in the Outer surface of the piston 20 arranged sealing ring 20a. In the lower part of the additional chamber 18 is still a helical spring 21, which are located on the underside 20c of the piston 20 and on the lower inner wall of the additional chamber 18 supports.

The bar 15 and the piston 20 are dimensioned so that the lower surface 15c of the bar 15 is smaller than the sum of the upper surfaces 20b of the pistons 20.

The mode of operation of the device according to FIG. 3 is as follows:

In the rest state, i.e. when the compressed air line 16 is vented, the pistons 20 are due to the action of the coil springs 21 pressed upwards and the bar 15 connected to the piston 20 is firmly attached to the upper inner wall of the Chamber 14 so that the slot 13 is closed. If the compressed air line 16 is now put under pressure, it acts this pressure initially in the lower part of the chamber 14 on the lower surface 15c of the strip 15 and increases the pressure

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push this bar upwards. In addition, the compressed air enters the additional Karomern 18 through the connecting channels 19, so that the pressure in the upper part of the additional chambers 18 increases. After a certain period of time, which depends in particular on the diameter of the connecting channels 19, corresponds to Pressure in the upper part of the additional chambers is the pressure within chamber 14. This pressure now acts on the upper surfaces 20b the piston 20. The difference between the areas of the lower surfaces 15c of the bar 15 and the upper surfaces 20b of the piston 20 is now designed so that at the latest at the moment of pressure equalization between the two chambers resulting from the spring force and the pressure on the underside of the bar 15 Force-acting closing force of the bar 15 is smaller than that due to the pressure on the upper surface 20b of the piston 20 resulting opposite opening force. At this moment, the bar 15 lifts off downwards, and there At the same time, the pressure prevailing in the chamber 14 now also acts on the upper surfaces 15d of the strip 15 acts, the opening force increases immediately and the bar 15 is pushed all the way down in the chamber 14 and the outlet slot 13 is released. The gas jet then emerges from the outlet slot 13 under high pressure. If the Chambers 14 and 18 are vented, the valve closes again automatically by the force of the helical spring 21.

The embodiment shown in FIG. 4 is very similar to the embodiment according to FIG. 3 in most details. The web 31 runs over a support body 32, which can also be part of a roller and which has a surface in its surface Has exit slot 33 in the transverse direction to web 31. The inwardly widening outlet slot 33 is with a chamber 34 connected, which in turn is connected to the compressed air line 36 and via connecting channels 39 with additional chambers connected is. The additional chambers 3B Heger · again in FIG

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below the chamber 34. In the chamber 34, the movable bar 35 is arranged, which has a wedge-shaped on its upper side Has attachment 35a, on both sides of which sealing strips 35b are arranged. When the valve is closed, the bar 35 rests against the top of the chamber 34, with the attachment 35a engages in the enlarged inner part of the slot 33. The bar 35 is connected to the piston 40 via a tappet 37, which is shown in FIG the additional chambers 38 are slidably arranged. The pistons are under the action of in the lower part of the auxiliary chambers

38 arranged coil springs 31, which are located on the one hand on the underside 40c of the piston 40 and on the other hand on spring plates prop up. The spring plates 42 are mounted in the support body 12 via threaded spindles 43. By changing their position, you can the bias of the coil springs 41 can be adjusted. The upper part of the additional chambers 38 is against the lower part sealed, with the help of a membrane 40a, which is between the piston 40 and the inner wall of the additional chamber is arranged.

The mode of operation of this valve arrangement is the same as that of the device described with reference to FIG. As a result the force acting on the bar 35 by the helical springs 41 via the pistons 40 is applied to the bar in the deflated state the compressed air line 36 to the top of the chamber 34 and closes the outlet slot 33. When the chamber 34 is put under pressure, the pressure first acts on the underside 35c of the bar 35. As a result of the connecting channels

39 a pressure equalization between the chamber 34 and the additional— Chambers 38 takes place, the pressure acts to an increasing extent but also on the upper surfaces 40b of the piston 40. The effective Areas are in turn dimensioned in such a way that at the latest when the pressure equalization has taken place, the one acting downward in FIG opening force is greater than the closing force acting upwards. At that moment the valve opens very quickly by moving the bar 35 downwards and the compressed air

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can emerge from the outlet slot 33. In this embodiment the pressure at which the valve opens can be changed by changing the preload of the coil springs 41 can be.

Claims
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Claims (13)

2? O0i95 - 13 claims Soldering method for knocking off a web of paper, cellulose or the like., characterized in that a sharply focused gas jet generated under high pressure is briefly directed essentially perpendicular to the surface of the web along a line running transversely to the web against the tensioned web. 2. The method according to claim 1 for webs which are provided with perforations extending transversely to the web, characterized in that the gas jet impinges on the web at or in the immediate vicinity of a perforation line. 3. The method according to claims 1 or 2, characterized in that the gas jet is generated with a pressure of 7 to 15 atmospheres. 4. Device for performing the method according to one of claims 1 to 3, characterized in that the tensioned web (I ₁ 11, 31) is guided over a support surface (2, 12, 32) which has a transverse direction to the direction of movement of the web Has slot (3, 13, 33) which is connected to a compressed air line (6, 16, 36) via a valve (5, 15, 35). 5. Apparatus according to claim 4, characterized in that the bearing surface is the outer surface of a roller (3) around which the web (1) is guided, the valve (5) being activated after a predetermined number of revolutions of the roller (3) will. 6. Device according to claims 4 or 5, characterized in that the valve chamber (4, 14, 34) as parallel - 14 - 409881/0224 23o0195 to the longitudinal direction of the slot (3, 13, 33) extending channel is formed in which as a valve cone a is arranged over the entire length of the channel extending, movable bar (5, 15, 35), which in the closed position of the valve rests sealingly against the inner end of the slot (3, 13, 33). 7. Apparatus according to claim 6, characterized in that the valve chamber (4) is connected to at least one additional chamber (8a, 8b) via at least one connecting channel (9a, 9b) and, in the closed position of the valve, the compressed air line (6) via a Check valve (5a, 5b) is connected to the additional chamber (8a, 8b), while in the open position of the valve, the bar (5) is sealingly applied to the end of the compressed air line (6), and the additional chambers (8a, 8b) with the Slot (3) are in communication. 8. Apparatus according to claim 7, characterized in that the valve is constructed in the manner of a quick exhaust valve, the connecting channels (9a, 9b) opposite the j the end of the compressed air line (6) facing away from the \ Bar (5) open into the valve chamber (4) and the check valve is formed by elastic sealing lips (5a, 5b) arranged on the bar (5), which control the inflow from the compressed air line (6) to the additional chamber (8a, 8b ) releasing under pressure, place against the walls of the valve chamber (4). 9. Apparatus according to claim 6, characterized in that the valve chamber (14, 34) is connected to a plurality of additional chambers (18, 38) via connecting channels (19, 39) and the additional channels (18, 38) seen in the opening direction of the valve behind the Valve chambers (14, 34) are arranged and in each additional chamber (18, 38) a displaceable piston (3D /, 40) - 15 - 409881/0224 is arranged, which is sealed through an opening in the wall between the valve chamber (14, 34) and the respective Additional chamber (18, 38) guided plunger (17, 37) is connected to the bar (15, 35), the piston (20, 40) is under the force of a spring (21, 41) acting in the closing direction of the valve and the connecting channels (19, 39) each seen in the opening direction of the valve behind the strip (15, 35) of the valve chamber (14, 34) with the space in front of the piston (20, 40) connecting space of the additional chamber (18, 38) and the sum of the front surfaces (20b, 40b) of the pistons (20, 40) is larger than the rear surface (15c, 35c) of the bar (15, 35). 10. The device iiach claim 9, characterized in that the piston (2Q) rests against the side walls of the additional chamber (18) via a sealing ring (20a). 11. The device according to claim 9, characterized in that the piston (40) is connected to the side walls of the additional chamber (38) via a sealing membrane (40a). 12. Device according to one of claims 9 to 11, characterized in that the bias of the spring (41) is adjustable. 13. Device according to one of claims 4 to 12, characterized in that the slot (3, 13, 33) narrows from the inside to the outside like a nozzle. 409881/0224