WO2000066365A1

WO2000066365A1 - Method and device for conditioning a continuous paper sheet

Info

Publication number: WO2000066365A1
Application number: PCT/EP2000/003952
Authority: WO
Inventors: Rolf Enders
Original assignee: Baldwin Grafotec Gmbh
Priority date: 1999-05-03
Filing date: 2000-05-03
Publication date: 2000-11-09
Also published as: CN1302261A; DE19920091A1; JP2002542970A; EP1097045A1

Abstract

The invention relates to a method according to which between 0.1 and 2 % silicone is added to the rewetting fluid used to rewet freshly printed, dried paper sheets (1), so that the rewetting and silicone treatment of such paper sheets can be carried out in a single step. To condition a continuous paper sheet (1) in this manner a conditioning device (8) is used which comprises spray devices (9). At least each spray device (9) assigned to each printed side of the continuous paper sheet (1) can be supplied with a mixture of rewetting fluid and silicone.

Description

Method and device for conditioning a

Paper web

According to a first idea of the invention, the invention relates to a method for conditioning a freshly printed, dried paper web, which is cooled after drying and, at the latest, preferably before the last cooling, is acted upon on both sides with a conditioning agent which brings about rewetting, and according to a further idea of the invention to a device for carrying out this method with spray devices provided above and below the transport plane of the paper web, arranged in a region delimited by a cooling device arranged downstream of a dryer, preferably arranged upstream of the cooling device and which can be acted upon with a conditioning agent which brings about rewetting. It is known to feed the moisture lost during drying to a paper web dried in a dryer by so-called rewetting. For this purpose, water is applied to the dried paper web before or during passage through a chill roll stand. It is also known to treat a printed paper web with silicone to seal the printed surface. So far, so-called silicone plants have been used for this

Cooling roll stands are subordinate. Accordingly, two separate work steps and, accordingly, two separate application devices, which are spaced apart from one another by the cooling roller stand, have been required accordingly for the application of backwetting liquid and silicone to the web. This is cumbersome and therefore undesirable.

Proceeding from this, it is therefore the object of the present invention to improve a method and a device of the type mentioned at the beginning with simple and inexpensive means in such a way that the disadvantages mentioned are avoided.

This object is achieved in connection with the generic method in that at least the conditioning agent which can be supplied to a printed side of the paper web consists of a mixture of backwetting liquid and silicone.

The device-based solution consists in the fact that at least those printed on the device of the generic type A spraying liquid and silicone mixture can be applied to each side of the paper web associated spray device.

The measures according to the invention ensure that the application of silicone takes place together with the rewetting. A separate silicone plant is therefore not necessary, which means that the associated structural effort and space are eliminated. This also has an advantageous effect on the accessibility of the web in the area between the chill roll stand and the downstream folder, where silicone plants were previously located. Another, very special advantage of the measures according to the invention can be seen in the fact that the silicone, together with the backwetting liquid, can penetrate deeply into the paper web and practically enforce it. In contrast to the previous silicone treatment, this is therefore not only treated with silicone on the surface, but also in deeper cross-sectional areas. The advantageous consequence of this is that not only is the surface roughness reduced, but that the paper web as a whole is made extremely flexible and easily deformable. In longitudinal and transverse folding, comparatively sharp fold lines can therefore be achieved in an advantageous manner. A previous treatment with a folding aid liquid can therefore often be dispensed with. The silicone treatment integrated into the remoistening treatment, and accordingly further upstream than before, advantageously also results in the cooling rollers of the cooling roller stand being light Preserve Süikon lift, which counteracts the deposit of paint on the cooling rollers and improves the Wäπnelleitung and thus the cooling effect. In addition, the deeply penetrating silicone treatment according to the invention of the paper web reduces its static charge, which can facilitate further treatment, for example in the folder.

Advantageous refinements and appropriate further training of the higher-level measures are specified in the subclaims.

It is therefore expedient to apply a mixture of backwetting liquid and silicone to each side of the paper web. This ensures that the paper web is made flexible in the best possible way, regardless of whether only one or both sides are printed. In addition, this eliminates any adjustment work when switching from one-sided web to two-sided web.

Another expedient measure can consist in the fact that the mixture forming the conditioning agent contains 0.1% - 2% silicone and the rest water. This allows the silicone consumption to be kept within limits. Nevertheless, excellent results can be expected in the above sense.

In a further development of the higher-level measures, a quantity control device can be assigned to the spray devices be acted upon by means of a pump cooperating on the suction side with a container provided with a level switch, the container being connected to a water supply line which contains a shut-off valve which can be actuated by means of the level switch and a quantity measuring device, and can be acted upon by silicone by means of an admixing device, which is in Dependent on the output of the quantity measuring device actuatable metering pump, which interacts on the suction side with a silicone container. With simple means, these measures result in an exact dosing of the silicone portion.

Further advantageous refinements and expedient further developments of the superordinate measures are specified in the remaining subclaims and can be found in more detail in the following description of the examples with reference to the drawing.

The drawing described below shows a schematic longitudinal section through a device according to the invention.

The field of application of the present invention is usually rotary rotary printing presses, which are followed by a dryer and a cooling roller stand following this. Arrangements of this type are known per se and therefore require no further explanation. The paper web 1 indicated in the drawing, which is said to have been printed on both sides in a non-illustrated rotary rotary printing press, passes through a dryer 2 following the last printing unit of the non-illustrated rotary rotary printing press and then a cooling roller stand 3. The dryer 2 has three in the running direction Zones arranged one behind the other in the paper web 1, namely a heating zone 4, a temperature-maintaining zone 5 and a temperature-lowering zone 6. A compartment of the dryer 2 is assigned to each zone. Partition walls are provided between the successive compartments, each of which has a through slot for the paper web 1.

In the heating zone 4 and in the temperature maintenance zone 5, the paper web 1 is subjected to hot air, as indicated by nozzles 7. The compartment assigned to the temperature-lowering zone 6 contains a conditioning device designated as a whole by 8, which serves to act on the freshly printed and dried paper web 1, which has lost a lot of moisture during drying in the heating zone 4 and the temperature-maintaining zone 5, with a back-moistening liquid and at the same time with silicone . Water is used for rewetting, by which the water is replaced which the paper web 1 lost during drying. By treating the freshly printed and dried paper web 1 with silicone, the surface is sealed, the surface roughness is reduced and the suppleness and foldability are improved. If the webs are only printed on one side, the silicone treatment can be limited to the printed side of the respective web. However, it is desirable that the silicone not only remain on the surface, but with the

Backwetting liquid penetrates into deeper layers, which makes the paper particularly supple. For this reason, the unprinted side of a paper web that is only printed on one side is expediently not only loaded with liquid for backwetting, but also with silicone. In the example shown, the paper web 1 is to be printed on both sides, so that silicone treatment on both sides is provided in any case.

The silicone is added to the water used as the backwetting liquid. The silicone concentration is between 0.1% and 2%, depending on the type of paper, web speed, etc. The rest is water. By treating the paper web 1 with the conditioning agent formed by the mixture mentioned, a rewetting and silicone treatment of the paper web 1 are carried out at the same time.

The conditioning agent applied to the paper web 1 is partially evaporated. The heat of vaporization is withdrawn from the paper web 1, whereby it is cooled in the desired manner. This evaporating part of the conditioning agent is used in the Of course, dimensioning of the quantity supplied is taken into account.

The one formed by said mixture

Conditioning agent is expediently sprayed onto the paper web 1 without contact. In the example shown, this still takes place within the dryer 2 in the temperature reduction zone 6 containing the outlet of the dryer 2. However, it would also be conceivable to provide the conditioning device 8 outside the dryer 2, for example in the region between the dryer 2 and the cooling roll stand 3 or in the cooling roll stand 3. Since the conditioning device 8 u.a. a rewetting is carried out, a subordinate arrangement of the cooling roll stand separates the

Conditioning device.

The above-mentioned conditioning device 8 contains nozzle bars 9 arranged above and below the transport plane of the paper web 1, which are continuous over the entire width. In the example shown, a nozzle bar is provided in each case. Of course, one of several nozzle bars could also be used

_* Spray device formed may be provided. The conditioning agent supplied to the nozzle bar 9 is blown out by compressed air, so that there are sharp spray jets 10, which are also able to break up the laminar air layer adhering to the paper web 1, which is loaded with evaporating solvent, etc. The nozzle bars 9 are accordingly with conditioning liquid and Compressed air, as indicated by the supply lines 11, 12. The supply line 11 is assigned to the conditioning liquid and the supply line 12 to the compressed air.

To ensure reliable channeling of the spray jets 10, each of the nozzle sheets 9 is assigned a spray chamber 13 which is roof-shaped or V-shaped in cross section. Drip traps can be attached to the lower ends of the walls of the upper spray chamber 13 which are inclined in a roof shape. The spray chambers 13 are each arranged in an associated suction chamber 14, which is suctioned off by means of a blower 15. This prevents air laden with liquid from escaping from the condenser device 8 and possibly leading to condensation outside the dryer 2. The blowers 15 can blow out into the dryer 2, as a result of which the fresh air drawn in from the outside is mixed with air which has already been preheated, which reduces the energy requirement. A cooling unit 16 is arranged upstream of each blower 15. This acts as a condenser to separate the liquid in the air, which primarily contains water, but can also contain silicone and solvents.

A supply control device in the form of a valve 17, 18 is assigned to the supply lines 11 and 12, respectively. The valves 17, 18 are controlled by means of a control or regulating device 19, as by not closer designated signal lines is indicated. The control device 19 determines suitable control pulses for the valves 17, 18 from various actual values, for example the temperature and / or humidity of the paper web 1 before and after the configuration device 8. The actual values are measured by sensors (not shown in more detail) and via Signal lines supplied to the control device 19, which is provided with suitable actual value inputs 20.

The supply lines 11, 12 are here forked after the respectively assigned valve 17, 18 into two parallel branches, each leading to an associated nozzle bar 9. However, it would also be conceivable to assign a corresponding supply device to each nozzle bar.

The supply line 12 assigned to the compressed air is connected upstream of the valve 18 to a compressed air source 21, for example an existing compressed air network. The supply line 11 assigned to the conditioning means is connected upstream of the assigned valve 17 to a supply device 22 provided with a water inlet and a silicone mixing device. In the example shown, this contains a pump 23 which is located on the suction side of a container 24 which contains the required conditioning liquid in the form of the mixture of water and silicone mentioned with a silicone concentration of 0.1% to 2%. The pump 23 is parallel to the downstream one by means of the control device 19 Valve 17 can be controlled, as indicated by parallel signal lines.

The container 24 is connected via a water line 25 to a water source, for example an existing water line network. In the water pipe 25 there is a water meter 26 which measures the flow rate. The water clock

26 is a shut-off valve 27. The container 24 is provided with a level switch 28 through which the shut-off valve

27 can be controlled, as indicated by a signal line. The admixing device provided for the admixture of silicone contains a metering pump 29 which is on the suction side against a silicone container 30 and whose outlet opens into the container 24. As indicated by a signal line, the metering pump 29 can be controlled by means of the water meter 26 in such a way that the desired mixing ratio of water and silicone is achieved. In order to avoid segregation in the container 24, this can be assigned a rolling or stirring device.

Although a particularly preferred exemplary embodiment of the invention has been explained in more detail above, this is not intended to imply any limitation. Rather, a number of possibilities are available to the person skilled in the art to adapt the general idea of the invention to the circumstances of the individual case. For example, it would also be conceivable, as already mentioned, for the conditioning device 8 in the region between the outlet of the dryer 2 and the first To arrange the cooling roll of the cooling roll stand 3 or to integrate it into the cooling roll stand 3. It is only important that the rewetting and the silicone treatment are carried out together by using a mixture of silicone and water before the paper web 1 leaves the chill roll stand.

Claims

Expectations

1. A method for conditioning a freshly printed, dried paper web, which is cooled after drying and at the latest, preferably before the last cooling, a conditioning agent causing rewetting is applied to both sides, characterized in that at least that which can be fed to a printed side of the paper web Conditioning agent consists of a mixture of backwetting liquid and silicone.

2. The method according to claim 1, characterized in that each side of the paper web is acted upon with a mixture of jerk moistening liquid and silicone.

3. The method according to any one of the preceding claims, characterized in that the mixture forming the conditioning agent contains 0.1% - 2% silicone and the rest water.

4. The method according to any one of the preceding claims, characterized in that the mixture forming the conditioning agent is sprayed onto the paper web without contact.

5. The method according to any one of the preceding claims, characterized in that the conditioning agent containing silicone is applied to the paper web before it is cooled.

6. The method according to claim 5, characterized in that the

Before leaving a dryer, the paper web is charged with the conditioning agent-forming mixture of silicone and water.

7. Device for carrying out the method according to one of the preceding claims with above and below the transport plane of the paper web (1) provided in a by a dryer (2) downstream cooling device (3) limited area arranged, preferably the cooling device (3) upstream Spray devices (9) which can be acted upon with a conditioning agent which brings about rewetting, characterized in that at least the spray device (9) assigned to each printed side of the paper web (1) can be acted upon with a mixture of liquid remoistening liquid and silicone.

8. The device according to claim 7, characterized in that the two sides of the paper web (1) associated spraying devices (9) can be acted upon with a mixture of jerk moistening liquid and silicone.

9. The device as claimed in claim 7 or 8, characterized in that each spray device (9) which can be acted upon with backwetting liquid and silicone is arranged upstream of the cooling device (3).

10. Device according to one of the preceding claims 7 to 9, wherein the dryer (2) has a heating zone (4), temperature maintaining zone (5) and temperature reduction zone (6), characterized in that the paper web (1) in the region of the temperature reduction zone (6 ) can be acted upon with the mixture of silicone and water forming the conditioning agent.

11. Device according to one of the preceding claims 7 to 10, characterized in that the spraying devices (9) can be acted upon with the conditioning agent and with compressed air for blowing out the conditioning agent.

12. Device according to one of the preceding claims 7 to 11, characterized in that the spray devices (9) are each arranged in a spray chamber (13), which in turn is received in a suction chamber (14), which by means of an associated, preferably in the Suction device (15) blowing out the dryer (2), which is preferably preceded by a cooling device (16).

13. Device according to one of the preceding claims 7 to 12, characterized in that the spray devices (9) at least on the conditioning agent side is associated with a quantity regulating device (17) which cooperate by means of a container (24) provided on the suction side with a level switch (28) Pump (29) can be acted upon and that the container (24) is connected to a water pipe (25) and can be acted upon with silicone by means of an admixing device.

14. The apparatus according to claim 13, characterized in that in the water line (25) by means of the level switch (28) operable shut-off valve (27) and a quantity measuring device (26) are provided and that the silicone admixing device is a function of the output of the quantity measuring device (26) operable metering pump (29), which cooperates on the suction side with a silicone container (30) and whose outlet opens into the container (24). CHANGED REQUIREMENTS

[Received at the International Office on October 10, 2000 (10/10/00); original claims 1-14 replaced by new claims 1-12 (3 pages)]

1. A method for conditioning a freshly printed, dried paper web, which is cooled after drying and subjected to a rewetting conditioner on both sides before the last cooling, characterized in that at least one printed side of the paper web is made with a mixture of Backwetting liquid and silicone existing conditioning agent is applied and that this mixture is applied to the paper web before cooling.

5. The method according to any one of the preceding claims, characterized in that the paper web is loaded with the conditioning agent-forming mixture of silicone and water before leaving a dryer.

6. Device for performing the method according to one of the preceding claims with above and below the transport plane of the paper web (1) provided, arranged in a region of a dryer (2) downstream cooling device (3) limited area, the cooling device (3) upstream spraying devices (9) which can be acted upon with a conditioning agent which brings about rewetting, characterized in that at least the spraying device (9) assigned to each printed side of the paper web (1) can be acted upon with a mixture of jerk moistening liquid and silicone, each with jerk moistening liquid and silicone Actuable spray device (9) is arranged upstream of the cooling device (3) and that each such spray device (9) is preceded by devices (25, 27; 29, 30) for the metered supply of backwetting liquid and silicone.

7. The device according to claim 6, characterized in that the two sides of the paper web (1) associated spray devices (9) can be acted upon with a mixture of jerk moistening liquid and silicone.

8. Device according to one of the preceding claims 6 or 7, wherein the dryer (2) has a heating zone (4), temperature maintenance zone (5) and temperature reduction zone (6), characterized in that the paper web (1) in the region of the temperature reduction zone (6 ) can be acted upon with the mixture of silicone and water forming the conditioning agent.

. Device according to one of the preceding claims 6 to 8, characterized in that the spraying devices (9) can be acted upon with the conditioning agent and with compressed air for blowing out the conditioning agent.

10. Device according to one of the preceding claims 6 to 9, characterized in that the spray devices (9) are each arranged in a spray chamber (13), which in turn is received in a suction chamber (14), which by means of an associated, preferably in the Suction device (15) blowing out the dryer (2), which is preferably preceded by a cooling device (16).

11. The device according to any one of the preceding claims 6 to 10, characterized in that the spray devices (9) at least on the conditioning agent side is assigned a quantity regulating device (17) which cooperates by means of a container (24) provided on the suction side with a level switch (28) Pump (29) can be acted upon and that the container (24) is connected to a water pipe (25) and can be acted upon with silicone by means of an admixing device.

12. The device according to claim 11, characterized in that in the water line (25) by means of the level switch (28) operable shut-off valve (27) and a quantity measuring device (26) are provided and that the silicone admixing device is a function of the output of the quantity measuring device (26) operable metering pump (29), which cooperates on the suction side with a silicone container (30) and whose outlet opens into the container (24).