EP0627311B1 - Web cooling device - Google Patents

Abstract

The general purpose of the present invention is to provide a method for cooling a hot web. In this method, liquid is applied to one side or to both sides of a hot web (16) by means of liquid applicator rollers (24,28) located on opposite sides of a web (16) running through, this taking place after a web has run through a dryer (14). The web is cooled as a result of the evaporation of the liquid on one or on both sides of the web. According to one version of the present invention, a housing (12) is provided next to a dryer (14), a hot web running through the dryer and the housing. This housing (12) comprises a pressure roller (20), a support roller (22), liquid applicator rollers (24,28) and a cooling roller (31), the web (16) running over all these rollers. <IMAGE>

Description

The present invention relates to a device for cooling a web.

Devices for cooling printing material webs are known.

From DE-OS 32 41 117 A1 is a device for cooling a heated printing material web known, in which the printing material web guided over a first and a second support cylinder and via the first and second, to the respective support cylinder employed application rollers with coolant, e.g. Water, is moistened.

U.S. Patent 5,121,560 shows an apparatus for cooling a heated substrate coming from a dryer, at which the printing material web is guided around a cooling roller and an elastic one attached to the chill roll Liquid application roller coolant from below located reservoir on the outside of the chill roll Applying substrate web.

Devices are also known from the prior art which Cool over pipes or convection, either too quickly or is cooled too slowly. This causes an undesirable Investment in terms of costs and quality problems, such as. Loss of gloss or steam due to continuous evaporation of solvents.

With the present invention, the shortcomings of State of the art corrected by predominantly through the web Evaporation of liquid - and not via a control system or Convection - cooling, which causes moisture on the track comes at risk of shrinking or curling the train as well as the static electricity in the train decreased. With an offset dryer, the web is except for one Residual moisture of 2% dried. To the moisture content to increase it again to 4-6%, removes the web from the room air Humidity. According to the present invention, this can Process by providing an available water or other liquid source can be brought about more quickly.

An essential feature of the present invention is that Cooling a web in a cooling process where liquid such as. Water, is applied to a web, the The temperature of the liquid is lower than that of the web. In In the preferred embodiment, the temperature behaves the web versus the temperature of the liquid so that it too an evaporative cooling comes, taking the utilizes latent heat of vaporization.

Fig. 1

ist eine Draufsicht auf eine Flüssigkeitauftragsvorrichtung;

Fig. 2

zeigt das Auftragen einer kühlen Flüssigkeit auf eine heiße Bahn;

Fig. 3

zeigt - ähnlich der Ansicht von Fig. 2 - ein Temperaturprofil und einen Wärmefluß an der Verbindungsstelle von Bahn und Flüssigkeit;

Fig. 4

zeigt den Temperaturausgleich zwischen Bahn und Flüssigkeit im Diagramm;

Fig. 5

ist eine Schnittansicht eines Trockners, der in Betrieb ist, und einer durch diesen hindurchlaufenden Bahn;

Fig. 6

zeigt eine Bahnkühlungsvorrichtung und einen Bahntrockners;

Fig. 7

zeigt eine Bahnkühlungsvorrichtung;

Fig. 8

zeigt ein Ausführungsbeispiel einer Bahnkühlungsvorrichtung und eines horizontal angeordneten Trockners;

Fig. 9

zeigt ein weiteres Ausführungsbeispiel einer Bahnkühlungsvorrichtung und eines vertikal angeordneten Trockners;

Fig. 10

zeigt ein weiteres Ausführungsbeispiel einer Bahnkühlungsvorrichtung und eines Trockners; und

Fig. 11

zeigt ein weiteres Ausführungsbeispiel einer Bahnkühlungsvorrichtung und eines Trockners.

Other objects of the present invention and many of the advantages associated with the present invention will be better understood in conjunction with the following detailed description and accompanying drawings, in which identical elements are given the same reference numerals in all figures.

Fig. 1

Figure 4 is a top view of a liquid application device;

Fig. 2

shows the application of a cool liquid to a hot web;

Fig. 3

shows - similar to the view of Figure 2 - a temperature profile and a heat flow at the junction of the web and liquid.

Fig. 4

shows the temperature compensation between web and liquid in the diagram;

Fig. 5

Fig. 3 is a sectional view of a dryer in operation and a web passing therethrough;

Fig. 6

shows a web cooling device and a web dryer;

Fig. 7

shows a web cooling device;

Fig. 8

shows an embodiment of a web cooling device and a horizontally arranged dryer;

Fig. 9

shows a further embodiment of a web cooling device and a vertically arranged dryer;

Fig. 10

shows a further embodiment of a web cooling device and a dryer; and

Fig. 11

shows a further embodiment of a web cooling device and a dryer.

1 is a top view of a liquid application device 10, which applies water to both sides of a hot track 16, to cool the web in an evaporation process. A Housing 12 is arranged next to a dryer 14 and includes one Number of vertically arranged components contained therein, the are described in detail below. A hot track 16 runs through a slot 18 provided in the dryer 14 in the inside of the housing 12 where the web is first between one Press roll 20 and a backup roll 22 passes through. Then runs the hot web 16 via a liquid application roller 24 one a trough 27 and a reservoir 29 comprising moistening device 26, the surface of the liquid application roller 24 and one side 16a of the web 16 continuously moist holds. The web 16 then runs over another liquid application roller 28 a trough 33 and a storage container 35 comprehensive humidifier 30 to the surface of the Liquid application roller 28 and the other side 16b of the web 16 keep moist. The following pictures show humidification units to see the a trough and a storage container include. The web 16 then runs over a cooling roller 31 and leaves the housing 12, the evaporation process for it ensures that both sides of the hot web 16 are cooled. The Liquid application rollers 24 and 28 are driven by motors 32 and 34 driven.

Depending on the roller speed and the surface condition the roller - depending on whether the roller is different Has etching pattern or is smooth, or whether the Roller rotates in or against the direction of web travel - can be different Amounts of liquid applied to the web will. How much liquid is applied also depends on that Diameter of the roll in relation to the web running speed and the liquid level in the humidifier.

Fig. 2 shows a liquid application roller 24 which is cool Applies liquid 36 to hot web 16 (the reference numerals refer to the previously mentioned elements). The cold Liquid 36 located on the liquid application roller 24 will be at the transition point 39, where she takes the hot train 16 comes into contact, immediately brought to a boiling point range 38 and partially absorbed by the hot web 16, thereby the hot web 16 is cooled during the evaporation process becomes. Part of the liquid 36 remains in the form of recycled Liquid on the liquid application roller 24 and is transported back into the moistening device 26. A Small portion of the liquid 36 remains on the surface of the hot web 16 at point 42, evaporates together with the cooling Evaporation process and thus provides for a at 16a Web with a lower temperature.

Because the temperature of the amount of liquid 36 that is on the liquid roller 24 remains and in the form of returned liquid 40 is transported back, is usually higher than the temperature in the humidifier 26, the Temperature in the humidifier 26 to an undesired Level increase. Accordingly, means can be provided be that ensure that the liquid in the humidifier does not exceed a certain temperature by these means of the humidifier at regular intervals or keep feeding liquid or the trough that Storage container or the application roller with a heat exchanger (not shown) is provided.

Figure 3 is a view, similar to that of Figure 2, illustrating a temperature profile and heat flow in the interface 39 of web and liquid, with all reference numerals referring to the elements previously described. T ₁ - T ₈ illustrate the temperature gradient along hot web 16 that extends to point 16a where the web has cooled as a result of the evaporation process, where T _{1 is} the highest temperature and T _{8 is} the lowest temperature . T ₄ refers to the evaporation temperature, which is lower than T ₁ - T ₃ . Large temperature fluctuations in the web only occur in a relatively small area. The contours of the temperature profiles T ₁ - T ₈ illustrate the different temperatures on exactly opposite sides of the web 16. The lines 44a - 44n in the region of the temperature profiles T ₁ - T ₈ illustrate the heat flow from the web 16 and into the liquid 36.

Fig. 4 is a diagram illustrating the temperature balance between the web and the liquid 36, that is, the heat transfer from the web to the liquid. All reference numerals refer to the elements described above. Time is plotted on the x-axis and temperature on the y-axis in the coordinate system. time Time or track position 0-t ₁ Web before roller contact t ₁ -t ₂ Web is cooled to the evaporation temperature of the liquid (T _V ) Liquid evaporates t ₂ -t ₃ Liquid evaporates and absorbs heat t ₃ -t ₄ Temperature balance between web and liquid, through heat transfer to the liquid

Fig. 5 is a sectional view of a dryer 50 with a through this path 52; it is about just an application example of the teachings of the present Invention to which the invention as such is not limited is. The web 52 runs through a slot 56 into a drying chamber 54. A series of arranged in the air chamber opposite air rods 58a-58n and 60a-60n provide normal air heating and for web 52 to float. This method of airborne levitation of the web is the norm of the technique. The size of the angle formed with the horizontal, which the web passes through in this drying chamber between the vertical (i.e. 90 °) and the horizontal (i.e. up to 180 °). This figure shows the angle that is results when the upper boundary of the air chamber 62 is horizontal runs. An air-assisted turning device 64 changes that Direction of travel of the web 52 by almost 180 °. Because of the pressure that the airflow coming from the air rods creates, and the Web tension, the web takes up a certain position with respect air rods 58a-58n and 60a-60n. The air is warmed up and again heats up the web; it also removes the evaporating Solvent from both sides of the web. Special Care is taken in this construction that the A negative pressure develops between the air rod and the web is avoided, so the web is rather down to the air bar to move instead of moving them off the air bar. This procedure is state of the art. Until the web 52 to one second turning device 70 passes, it passes through another Arrangement of oppositely located in the air chamber Air rods 66a-66n and 68a-68n.

The air chambers 62 and 72, which are the upper and lower air rods Providing air to 58a-58n and 60a-60n is due to them respective ends 62a and 72a with the largest cross section and at their respective ends 62b and 72b with the smallest cross section to each other. This allows a single blower to be connected to both the upper air chamber 62 and the lower air chamber 72 at one end of the web dryer 14. A second Fan is at the other end of the dryer with reverse arrangement of an upper and a lower air chamber 74 and 76. There are two additional air chambers in this Provided in layers to allow a longer web run reach, the height of the dryer can be effectively used. A turning device 78 is at the outlet of the lower air chamber 76 provided and turns the web by about 90 ° to itself so to approach the vertical. Except for the degree of turning the turning device 78 is similar to the turning devices 64 and 70 educated. The height of the entire drying chamber 54 was thereby reduces that two arrangements from upper 62 and 72 and lower air chambers 74 and 76 are opposed while a even airflow exits the air rods that pass through the chambers 62, 72, 74, 76 are supplied. The space between the turning device 64 and 70 with air from two separate Air chambers filled. Because of this, it is not possible an exact pressure balance on the opposite side of the web to create. The air poles are therefore further apart spaced and the air supply is reduced so the web can happen without touching the poles. In this section is the sprinkling of the web by the vapors and the Railway heating reduced. This minor limitation is negligible constructive concession, because on the other hand the length dryer almost halved by the two 180 ° turns becomes. Every heating and sprinkling achieved in this run is advantageous because it means the total length of the drying path can be reduced again. It is obvious that the heating and sprinkling process in this section is maximal is.

Rollers 84 and 86 are arranged so that the liquid, e.g. Water or another medium, from troughs 88 and 90 evenly can be applied to the web 52, the liquid has a certain temperature. It is possible in this section to use more than two rollers and troughs. It it is conceivable to place the dryer further up or the web lead upwards on the turning device in order to add additional gain vertical space. The application rollers carry the liquid to the temperature of the web in the evaporation process to reduce. When leaving the housing, the temperature should the web below the evaporation temperature of the solvent lie. For offset printing inks, this temperature is approx. 80 ° C. This process takes place throughout the machine, with the Roller 92 is in contact with the web and in the web running direction turns. The roller 92 can also be circulated inside Liquid are cooled, causing contact with the web a constant surface temperature can be maintained can. The roller 92 also lowers the temperature by dissipating the heat from the web. The diameter this roller 92 and its wrap angle smooth any Wrinkles, possibly in previous process steps have arisen. The entire machine can thus be deployed of independent cooling and application rollers arranged downstream of the dryer dispense. The economy achieved thereby is reflected in the smaller space requirement as well as in a reduced one Number of devices to be installed. The present Design examples of this invention can be independent applied from each other without the main mode of operation to affect the other design examples.

Figure 6 illustrates the use of a web cooling device 150 in conjunction with a web dryer 152. The web dryer 152 includes a dryer housing 154 that opens a plurality of feet 156a-156n. Along the side surface a plurality of access doors 158a-158n are attached, and on the underside of the dryer housing 154 are nozzle or - Parking devices 160 provided. Combustion air blower 161 and 162 are attached and powered to dryer housing 154 those attached to the back of the dryer housing 154 Burner via lines 164, 166 and 168 with combustion air. Explosion vent and access hatches 170a-170n are located themselves on the floor, the back, the right and left Dryer housing 154 side. Between the web dryer assembly 152 and the web cooling device 150 is a transition chamber 172 provided. Once the web 174 this transition chamber 172 has passed through, there are solvent residues in it, which are disposed of as is known (prior art) can. The transition chamber 172 is with an access door 176 Mistake. For measuring the temperatures of the dryer housing 154 and web 174 passing through web cooling device 150 are on the dryer housing or the web cooling device housing 182 infrared pyrometers 177, 178, 180 are provided. An engine 184 drives an upper chill roll 186 and a lower chill roll 188 as well as other components - as described below in FIG. 7 - on. To apply liquid to web 174 are upper and lower liquid application rollers 190 and 192, inclusive the humidification device described above, provided between the upper and lower cooling rolls 186 and 188.

7 illustrates a web cooling device 150. Various Components - including an upper chill roll 186, a cooled pressure roller 194, a lower cooling roller 188, an upper liquid application assembly 196 and a lower one Liquid application assembly 198 - are on and around a housing 182 attached around. A drive motor 184 is on the Fixed top of housing 182 and includes a drive belt 200, around a clutch assembly 202, a fixed Tensioner roller 204, the lower cooling roller 188, an adjustable Belt idler 206 and the upper cooling roller 186 passed around becomes. Belt 201 runs between the clutch assembly 202 and the cooled pressure roller 194 on the drive pulleys 208 and 210.

The top applicator roller assembly includes one on one Swivel arm 212 mounted liquid application roller 190. This Liquid application roller 190 is arranged in a container 214. For the sake of clarity, the storage containers are not pictured. Around the swing arm 212 and the liquid application roller 190 to move and adjust laterally actuates a Pneumatic cylinder 216 a linkage 218 in a pivot point 220 so that the wetted liquid roller makes pressure contact on the heated web 174 that is between the upper chill roll 186 and the lower cooling roller 188 passes through. The lower one Applicator roller arrangement corresponds to the above in operation and construction and includes one mounted on a swing arm 222 Liquid application roller 192, a trough 224, one Pneumatic cylinder 226, linkage 228 and a pivot point 230. Upper and lower flaps 232 and 234 provide access to the Interior of the case.

example

The optimal temperature of the liquid is usually included 30 ° C or below. This is necessary to get from the web to the To reduce application rollers 190 and 192 transferred heat. If the Application rollers 190 and 192 become too warm, the color of the Transfer web 194 to the application rollers 190 and 192 and sets get stuck there. The critical for the application rollers 190, 192 Temperature depends on the color composition and lies in the generally at approx. 60 ° C.

Before the web comes into contact with the application rollers 190, 192, the web temperature is usually between 120 ° C and 100 ° C. After contact with both application rollers and subordinate ones Chill rolls, the web temperature must be below about 80 ° C, such as previously described.

Because with a fluctuating liquid level different Amounts of liquid would be applied to the web Humidification device be constantly refilled liquid. This is usually achieved by using a Pump the liquid through a baffle in the humidifier transported, a liquid excess provided becomes. Occurs over an overflow or overflow pipe this excess liquid then from the humidifier and is placed in a main container, e.g. a storage container, which supplies the pump. Via a float valve, Sensors that indicate the liquid level, or a solenoid valve can either continuously humidify the device or refilled in batches. It is possible, to use a heat exchanger or an equivalent amount to exchange heated liquid for cold liquid, so as to maintain the desired temperature as described above. Returned from the trough to the storage container Liquid can be paper fibers or condensed color solvent oil contain, which should preferably be filtered, before it is returned to the cycle.

The diameter of the application roller is approximately 1.4 m wide machine about 10 cm. This diameter is not critical however, is a compromise in that it is large is enough not to be deformed, its radius is large enough a reasonable distance between the web and the trough, large enough to create a preferred contact area to the web without the Deforming the web excessively or acting forcefully on it, and large enough in that their dimensions are favorable in terms of are the layout. Appropriate dimensions are dimensions which are in the range of 7.5 to 15 cm.

The liquid level in troughs 214 and 224 is sufficient to the application rollers 190, 192 e.g. about a quarter immerse or third of their diameter; this is only one Example that is not intended to limit the invention. Thereby the roll neck can extend beyond the trough, but not to avoid leakage need to be sealed and still have an adequate surface area for the transfer of heat from the roller to the Have liquid ready. The total content in the troughs is small to minimize the weight, because the troughs in the Move the rail transport with the rollers 190, 192. A little content facilitates fluid circulation for maintenance a uniform temperature of liquid and roller. The fluid level affects the time and the route of the liquid film on the roller and thus on the thickness of the liquid film when the liquid is applied to the web becomes. For this reason there is a constant fluid level of great importance.

In tests, e.g. a roller moving at a speed of 55 rpm turned counter to the web, sufficient Liquid on a web running at 1000 m per minute. The roller speed was controlled to be a fixed one Percentage of web speed. The maximum Liquid application ultimately depends on the web moisture certainly. Increasing web moisture generally improves handling in the area of the folder; being a Excess web moisture, however, cutting problems in the folder prepares. Thus, the preferred roller speed as fast as the process allows. At web speeds The application rollers of the Railway withdrawn.

8 shows an embodiment of a web cooling device 240 and a dryer 242, with a web 244 horizontal between an arrangement of horizontally aligned and opposite one another Air rods 246 is arranged and in one Web cooling device 240 is cooled.

9 shows a second exemplary embodiment of a web cooling device 250 and a dryer 252, a web 254 vertically between an array of vertically aligned and opposing air rods 256 is arranged and in a web cooling device 250 is cooled.

10 shows a third embodiment of a web cooling device 260 and a dryer 262, with a web 264 horizontally between an upper and a lower arrangement horizontally aligned and opposite air rods 266, 268 and turning devices 270, 272 is arranged and then is cooled in a web cooling device 260.

Fig. 11 shows a fourth embodiment of a web cooling device 273 and a dryer 274, a web 276 vertically between a left and a right arrangement vertically aligned and opposite air rods 278, 280 and is arranged via turning devices 282, 284 and is then cooled in a web cooling device 273.

REFERENCES

10th

Liquid application device

12th

casing

14

Web dryer

16

hot train

16a

web wetted on one side

16b

web wetted on both sides

18th

slot

20th

(cooled) pressure roller

22

(Cooled) backup roller

24th

Liquid application roller

26

Humidifier

27

trough

28

Liquid application roller

29

Storage container

30th

Humidifier

31

Chill roll

32

engine

33

trough

34

engine

35

Storage container

36

Coolant

38

Boiling point range

39

Liaison

40

returned liquid

42

Evaporation point

44a-n

Heat flow (dashed line)

50

dryer

52

train

54

Drying chamber

56

slot

58a-n

Air poles

60a-n

Air poles

62

upper air chamber

62a

End with the largest diameter

62b

Smallest diameter end

64

Turning device

66a-n

Air poles

68a-n

Air poles

70

Turning device

72

lower air chamber

72a

End with the largest diameter

72b

Smallest diameter end

74

upper air chamber

76

lower air chamber

78

Turning device

84

Applicator roller

86

Applicator roller

88

trough

90

trough

92

Chill roll

150

Web cooling device

152

Web dryer

154

Dryer housing

156a-n

Feet

158a-n

Access doors

160

Nozzle start and stop device

161

Combustion air blower

162

Combustion air blower

164

pipe

166

pipe

168

pipe

170a-n

Access hatches

172

Transition chamber

174

train

176

Access hatch

177

pyrometer

178

pyrometer

180

pyrometer

182

casing

184

engine

186

upper cooling roller

188

lower cooling roller

190

Liquid application roller

192

Liquid application roller

194

Pressure roller

196

upper liquid application arrangement

198

lower fluid application assembly

200

Drive belt

201

belt

202

Coupling arrangement

204

attached tension pulley

206

adjustable belt idler

208

Traction sheave

210

Traction sheave

212

Swivel arm

214

Humidifier

216

Pneumatic cylinder

218

Linkage

220

Pivot point

222

Swivel arm

224

Humidifier

226

Pneumatic cylinder

228

Linkage

230

Pivot point

232

flap

234

flap

240

Web cooling device

242

dryer

244

train

246

Air rod

250

Web cooling device

252

dryer

254

train

256

Air rod

260

Web cooling device

262

dryer

264

train

266

Air rod

268

Air rod

270

Turning device

272

Turning device

273

Web cooling device

274

dryer

276

train

278

Air rod

280

Air rod

282

Turning device

284

Turning device

Claims (9)

1. Device for cooling a printed material web heated in the dryer of a web-fed rotary printing machine,

   having a supporting roll or turning device (22, 78, 186), which is arranged downstream of the dryer (14, 50, 152, 242, 252) and guides the printed material web (16, 52, 174, 244, 254, 264, 276),

   having a second roll (31, 92, 188), which is arranged downstream of the supporting roll or turning device (22, 78, 186) and guides the printed material web (16, 52, 174, 244, 254, 264, 276),

   having a first liquid application roll (24, 84, 190) for the application of liquid to a first side of the printed material web (16, 52, 174, 244, 254, 264, 276),

   having a second liquid application roll (31, 86, 192) for the application of liquid to a second side of the printed material web (16, 52, 174, 244, 254, 264, 276), the liquid application rolls (24, 84, 190; 28, 86, 192) being arranged on mutually opposite sides of the printed material web (16, 52, 174, 244, 254, 264, 276), between the supporting roll or turning device and the second roll (22, 78, 186; 31, 92, 188),

   characterized in that the liquid application rolls (24, 84, 190; 28, 86, 192) are together assigned to a section of the printed material web that extends between the supporting roll or turning device and the second roll (22, 78, 186; 31, 92, 188) and are arranged offset with respect to each other and exert pressure contact on the printed material web, along a contact area, in such a way that wetting of the printed material web surface is effected.
2. Device according to Claim 1, characterized in that the supporting roll or turning device and the second roll (22, 78, 186; 31, 92, 188) can be cooled.
3. Device according to one of the preceding claims, characterized in that liquid-filled troughs (27, 214; 33, 224) into which the liquid application rolls (24, 84, 190; 28, 86, 192) dip, at least partly, are provided.
4. Device according to Claim 3, characterized in that means which regulate the liquid level in the troughs (27, 214; 33, 224) are provided.
5. Device according to one of the preceding claims, characterized in that the liquid applied is cooled.
6. Device according to one of the preceding claims, characterized in that the liquid application rolls (24, 84, 190; 28, 86, 192) are driven by motors (32, 34).
7. Device according to one of the preceding claims, characterized in that the liquid application rolls (24, 84, 190; 28, 86, 192) rotate in a direction counter to the direction of movement of the printed material web (16, 52, 174, 244, 254, 264, 276).
8. Device according to one of the preceding claims, characterized in that the rotational speed of the liquid application rolls (24, 84, 190; 28, 86, 192) is a fixed percentage of the printed web speed.
9. Device according to one of the preceding claims, characterized in that at least the circumferential surface of one of the liquid application rolls (24, 84, 190; 28, 86, 192) has a surface structure, preferably an etched pattern, that is beneficial to the transfer of liquid to the printed material web.

Images