FI93038C - Procedure and plant for controlling the tip drawing tape in a paper machine - Google Patents

Description

5,93038

Method and apparatus for headband control in a paper machine Förfarande och anläggning vid styming av spetsdragningsbandet i en pappersmaskin

The invention relates to a method and apparatus for controlling a headband in a paper machine.

The problem with the rope head in the two-wire export area is to make the headband-10 tin strip fly in the free space to the next wire / cylinder rig. Nowadays, the strip hits between the wire guide roll and the wire / cylinder half of the groove. In this case, the headband remains loose, which causes problems when the tape flares. Some looseness is also generated before the headband that collides with the wire travels to the wire / cylinder groove that accompanies the wire.

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Actual threading difficulties occur at group intervals (single-wire-two-wire export and two-wire export / two-wire export), where the head-thread geometry deviates from normal. In this case, wire guide rolls is not always obtained so arranged that the strip could be made to fly in exactly the right direction at the right point, but in most cases the tape 20 impinges against the receiving side and there is a loose wire guide.

When the humidity of the headband and / or the temperature of the drying cylinder deviates considerably from the normal driving situation, the headband tends to burn onto the surface of the cylinder.

In this case, the wire moving to the wire guide roll cannot throw the strip into the next wire / sy-25 cylinder groove, but the strip follows the surface of the drying cylinder. The end of the cylinder is packaged in the region of the headband.

Conventional headband rope routing has proven to be a problem at high speeds. For example, rope breaks have been a nuisance.

According to the invention, the paper machine is provided with an air blowing device arranged close to the roll of the roll / cylinder of the paper machine and the wire conveyed in connection therewith, and in which the air blowing is directed towards the cylinder surface and further obliquely towards the wire between the wire and the cylinder. Thus, in the solution according to the invention, the headband removed from the wire to the cylinder / roll surface is moved by air blowing away from the cylinder / roll surface connection and so that the headband passes back to the wire 5 and to the accompanying cylinder / roll. In the solution according to the invention, the air blowing directed at the headland is started before the headband arrives at the blowing point. Blowing stops when the headband is guided forward to the next cylinder / roll.

10 In the area of the two-wire export, the blowpipe solves the problems of the prior art. The blowing can be timed correctly and can be used to detach the strip from the surface of the cylinder and, if necessary, press the strip from the surface of the cylinder onto the wire going to the wire guide roll. The starting direction of the tape is always the same and, if necessary, the tape follows the wire longer. In this case, it gets a straighter flight path and can be made longer with the help of a wire, 15 which means that the flight distance is shorter.

In group spacing, the use of the blowpipe is the same as above.

The blow pipe is preferably placed on the edge of the machine. The blowing works efficiently because it can be aligned close to the wire / cylinder groove, and the headband does not have time to engage the cylinder. The direction of the air jet is important and the air volumes should be reasonably small.

The exact alignment and timing of the blow is important. In the area of single wire export, scrapers 25 can be omitted altogether.

The blow pipe is placed parallel to the wire at a distance of about 50-400 mm from the wire. The distance from the mouth of the pipe is 10-200 mm from the surface of the cylinder.

In the method according to the invention, the blowing on the headband is actuated before the end of the headband appears from the 3,93038 gap between the cylinder and the wire. The blowing of said blow pipe is stopped when the end of the headband is guided forward to the next cylinder / roll. The end of the blowpipe is located on the side of the wire, on the wire or in the area of the headband. The blow pipe is led to said area from the side of the machine.

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The method according to the invention is mainly characterized in that in the method the air blowing is directed through the end of the air blowing tube, in the method the air jet is directed to the cylinder surface that the pressure level of the air jet is in the range of 20-500 kPa and the distance from the point of impact of the air jet to the cylinder surface in the range is 120-600 mm.

The apparatus according to the invention for controlling the headband is essentially characterized in that the air blowing tube is one through the end of which an air jet is directed to the cylinder surface so that the air blowing tube is arranged so that the air jet is directed obliquely to the cylinder and jet the angle between the tangent of the cylinder drawn at the point of intersection is in the range of 2-60 ° and that the distance of the point of intersection of the jet surface from the wire between the wire and the 20 cylinders / roll is in the range of 120-600 mm.

The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, to which, however, the invention is not intended to be exclusively limited.

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Figure 1 illustrates a preferred position of the air blow tube in connection with the cylinder / roll of the paper machine.

Figure 2 shows an axonometric partial view of the air blowing point of Figure 1. 30 j · 93038 4

Figure 3 shows an air blowing pipe installed in accordance with the invention in connection with the surface of a cylinder / roll. Based on the figure, the orientation and location of the air blow pipe is shown.

Figures 4A-4D show various gaming machine drying sub-concepts using the air blowing arrangement according to the invention.

Figures 5A-5C show cross-sectional views of the end of the air blow tube.

Figure 6 shows a pneumatic diagram of the air blow pipe and the blow control.

Figure 1 shows the air-tree arrangement of the headband located on the drying section of the paper machine. In the solution of the figure, the drying section comprises lower suction rollers and upper drying cylinders S. In the figure, the locations of the air blowing pipes are indicated by arrows F. 15 The following is an overview of the operation of the air blower. The headband P is passed from the drying cylinder S to the lower suction roll and from the suction roll further to the upper drying cylinder S. To guide the headband from the upper cylinder S to the lower suction roll, an air blowing jet D is directed to the surface S 'of the cylinder S. The air jet is guided along the surface of the cylinder S, absorbed therein forward 20 towards the gap K between the wire H and the cylinder S. When the headband appears from the gusset K, it immediately detaches from the cylinder surface S 'by the air blowing jet D. In this application, a suction roll generally refers to a roll solution within which the web is kept in connection with the roll by means of the vacuum created. In the application, a suction roll also means a conventional roll with a suction box.

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The air jet further guides the headband P back onto the wire H, whereby the headband P reliably travels to the lower suction roll. Thus, in the method and arrangement according to the invention, the cylinder S is thus provided with an air-blowing tube 10. The air-blowing tube 10 (Fig. 2) at its end 10a is arranged in the region of the headband and obliquely against the cylinder surface S '.

5,93038

Fig. 2 shows the air blowing point of Fig. 1 in an axonometric partial view obliquely to the machine direction. The air blowing tube 10 at its end 10a is arranged relative to the cylinder / roll surface S 'in its edge area and in the passage area of the headband P. As shown in the figure, the kit K is provided with a sensing device 11 which detects the entry of the tin strip P of the headrests-5 from the jaw K. In this case, the ballasting through the blow pipe is started. The detection device 11 can also be located with respect to the direction of travel of the track before the groove K, thus ensuring that the blowing is securely on when the headband appears from the groove K. Other types of guides for the headband blowing tubes are also possible.

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Figure 3 illustrates the device arrangement and method according to the invention. An air jet D is directed from the blow pipe 10 in the direction Lj towards the surface S 'of the cylinder / roll S. The air jet D meets the surface S 'of the cylinder / roll at an angle α. The angle α is the angle between the jet D and the direction Lj of the cylinder drawn at the point of intersection M of the cylinder surface S' and the direction Lj of the blow jet D. the angular range of a is 2-60 °. The distance of the jet D and the point of intersection M of the cylinder surface S 'from the girder K between the wire H and the cylinder S is in the range 120-600 mm. The distance C2 of the end 10a of the blow pipe 10 from the cylinder surface S 'is in the range of 10 mm to 200 mm. The distance C3 of the end 10a of the blow tube 10 from the wire H is in the range of 50 mm to 400 mm. The radius of the cylinder S is indicated by the stator 20 R and the direction of rotation of the cylinder S by the arrow 1 ^.

* The flow cross-sectional area of the blow pipe 10 is in the range of 20-350 mm2. The pressure level of the air used in the blowing is in the range of 20-500 kPa. The amount of air jet produced from the blow pipe 10 is in the range of 0.005-0.4 kg / s.

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Figure 4 A-4C shows different positions of the blow pipes in different drying section concepts. Fig. 4A shows the position of the blowpipe in the vicinity of the group gap E by means of the arrow F, where the web moves from the cylinder Sj from the group I to the cylinder group II to its cylinder S2. The headband P must carry a free space E which does not comprise a wire or 30 other elements supporting the headband P. As shown in the figure, the group I consists of suction rollers and steam-heated drying cylinders S and the group II consists of 6,93038 steam-heated cylinders only S. The headband in Group I comes from the suction roll to the upper cylinder 2 and further to group II Air blowing in the direction of arrow Fl indicated removed from the surface of the tail of Group I of the cylinder S j and transmits it to the wire 5 Hj context in which the web further passes through the free gap E of the wire connection with the H2 and further to the cylinder S2 in Group II.

Figure 4B shows a solution in which the arrows F show the locations of the air jet blowing pipes 10. The suction rollers are located in the upper position and the steam-heated cylinders 10 in the lower position. The air blows at the points indicated by the arrows F prevent the headband from moving on the cylinder surface S 'away from the connection of the wire H. The air blow detaches the headband from the cylinder surface and transfers it back to the wire H.

Fig. 4C shows a solution in which the head blowing strip P is guided from the group I to the group II by means of the air blowing tubes 10. The arrangement of the tubes 10 is shown by arrows F. The group I comprises upper suction rollers and lower heated drying cylinders S and group 11 comprises upper heated drying cylinders S and lower suction rollers. In the free space E between the groups I and II, the transport of the headband is facilitated by the air blowing indicated by the arrow 20 F]. Also in this solution, the headband is removed from the cylinder surface by means of air blowing and the headband is moved back to the wire H, in contact with and further from the wire towards the upper gap K between the wire H2 and the cylinder S.

Fig. 4D shows the support arrangement of the headband in a drying section group, in which the upper drying cylinder group comprises a wire Hj and the lower drying cylinder group comprises a wire H2.

Figures 5A-5C show different cross-sectional dimensions of the end 10a of the air blowing tube 10. With the cross-sectional shapes shown, the air jet can be efficiently directed through the roll surface tl 7 93038 to the headband. A conventional (not shown) cross-sectional shape of the end of the blow pipe 10 is a circular cross-section or an ellipse.

Fig. 5A shows a cross-sectional shape 5 of the end 10a of the air blowing tube 10, which is particularly suitable for guiding wide-width headband Ps. In this case, the air blowing must be directed over a wide area in the headband P to detach it from the cylinder / roll surface and guide it back to the wire H.

Figure 5B shows another cross-sectional view of the end 10a of the blow pipe 10.

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Figure 5C shows a third preferred cross-sectional shape of the end 10a of the blow pipe 10.

Figure 6 shows a pneumatic diagram of the blow pipe 10. The valve 12 of the blow pipe 10 is controlled to the open position by a control command from the sensor device 11a, i.e. the limit, which controls the blow V of the blow pipe 10 to the open position via the central unit 100. When the headband arrives at the detection station A2, the second sensor device 11b, i.e. the limit, detects the arrival of the headband P at the station A2. In this case, the air blowing of the air blowing pipe 10 in the previous position A1 is stopped and its valve V 20 is closed via a control command from the central unit 100, and the air blowing of the second blowing pipe 10 in the position A2 is started.

According to the invention, a separate group of blowpipes can also be controlled with one sensor.

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Within the scope of the invention, an embodiment is also possible in which the valve V is opened / closed after a certain pre-installable delay time.

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Claims (11)

A method of guiding the tip pulling belt in a paper machine, wherein a method of directing an air blow towards the surface (S ') of the cylinder / roller (S) against the direction of rotation (Lj) of the cylinder / roller and further to the gap (K) between the surface (S ') of the cylinder / roller and the wire (H) and the air blowing is pecked at the stage where or before the tip pull band emerges from the gap (K) between the surface (S') of the cylinder / roller and the wire (H), whereby the air blowing the tip drawing band from the cylinder surface (S ') and transmitting it back to the wire (H), characterized in that in the method the air blowing is directed via the end of an air blowing tube (10), in the process an air jet (D) is directed towards the cylinder surface / roller surface (S ') from the air-blowing tube (10) in such a direction (Lt) that the wink (a) between the key (Tt) drawn on the cylinder at the contact point (M) of the cylinder surface / roller surface (S') and the direction ( Lt) of the beam is in the range 2-60 ° , and that the pressure level of the air jet is in the range 20-15 500 kPa and the distance from the hit point (M) where the air jet (D) hits the cylinder surface to the gap (K) is in the range 120-600 mm. Method according to claim 1, characterized in that a method of blowing pipe (10) is used in the method, the distance (C2) of the end 20 (10a) from the surface (S ') of the cylinder being in the range 10 mm - 20 mm. and that the distance (C3) of the end (10a) of the blow tube from the wire (H) is in the range of 50 mm to 400 mm. 3. A method according to any of the preceding claims, characterized in that the method uses a saturated air-blowing pipe whose flow transverse area is in the range 20-350 mm 2. 4. A system for guiding the tip-pulling belt in a paper machine, wherein there is a blow tube (10) arranged to blow an air jet (D) obliquely to the surface (S ') of the cylinder / roller in such a way that the air jet (D) first directed towards the surface (S ') and thereafter along the surface (S') of the cylinder / roller along its surface against the gap (K) between the cylinder / roller and the wire (H), characterized in that there is a 93038 air blowing pipe (10), through whose end an air jet is directed towards the cylinder surface, that the air blowing pipe (10) is so arranged that the air jet (D) directed therefrom is directed in a direction (Lt) obliquely to the cylinder / roller surface (S '). ) in such a way that the angle (a) between the direction (Lj) of the beam (D) and the key (Tt) of the cylinder drawn at the point of contact between the beam (D) and the surface (M) is in the range 2-60 ° and the distance (Cj) of the beam (D) to the contact point (M) of the surface (S ') from the gap (K) between the wire (H) and the cylinder / wire (S) are in the range of 120-600 mm. Installation according to claim 4, characterized in that the distance (C2) 10 of the end (10a) of the air blowing tube (10) from the cylinder / roller surface (S ') is in the range 10 mm - 200 mm and that the distance (C3) of the end (10a) of the blow tube (10) from the wire (H) is in the range 50 mm - 400 mm. Installation according to any of the above claims 4 or 5, characterized in that the flow transducer of the blow pipe (10) is in the range 20-350 mm2 and that the pressure level of the air used in the blowing is in the range 20-500 kPa and the amount of air flowed from the blow tube is in the range 0.005-0.4 kg / s. An installation according to any one of the preceding claims 4-6, characterized in that the installation comprises a valve (V) which is controlled via a central unit (100) via controllers obtained from identification devices (1a, 1b), wherein v the device (11a), which in relation to the direction of travel of the tip pull band (P) was in a previous position (Aj), identifies the arrival of the tip pull band, the valve (V) is in the open position at the blow tube (10) in said position (At), and where another identification device (11b) identifies the arrival of the tip pull band, the valve (V) of the blower tube (10) is positioned in another position (A2) in the open position and correspondingly the valve (V) of the blower tube (10) is closed in the the former position (Aj), whereby the blow is always threaded at the stage where the tip pull band (P) is revealed from the gap (K) between the wire (H) and the cylinder (S). 93038 Installation according to any of the above claims 4-7, characterized in that the valve (V) closes and opens after a predetermined delay time. An installation according to any of the preceding claims 4-8, characterized in that the blowing pipe drive is arranged at the area of simple winding. An installation according to any of the above claims 4-8, characterized in that the blowing pipe drive is arranged at the area of double winding. 10 An installation according to any of the above claims 4-8, characterized in that the blowing pipe drive is arranged in a group gap between a single twist and a double twist or in a group gap between a double twist and a double twist. 15