EP1046874B1 - Dryer with integrated cooling unit - Google Patents

Description

The invention relates to a dryer with integrated cooling unit as he is subordinated particularly web-processing rotary printing machines, as well as on a Procedures for drying a material web.

US 5,471,847 discloses a web cooling device with the features according to the preamble of patent claim 1. With the disclosed there Solution, the disadvantages of previous drying concepts should be overcome by that the web primarily by evaporation of a liquid instead of through Heat conduction or convection is cooled. This leaves enough moisture in the Web, so that a shrinkage of the web is omitted and the static charge of the web takes a minimum. In a dryer for offset printing applications, the web is up Dried to 2% residual moisture content and thereby absorbed from the surrounding air Moisture up to a moisture content between 4% and 6%. This additional Moisture absorption on the environment according to US 5,471,847 by a specially to intended moisture applicator realized.

EP 0 723 126 A1 discloses a control device and an arrangement for one in one industrial dryer continuous drying process. In a dryer for floating a web for gradual drying of the web recirculates solvent-containing air inside the dryer. It will be a procedure for better control of the solvent-containing air inside the dryer proposed. This will cause the condensing of the solvents and various solvents based by-products significantly reduced or even completely eliminated. By means of the not only can a significant reduction in condensation, but also a more intensive mixing and thus a more even distribution of Solvent, raising overall safety levels, in which areas are avoided altogether, in which solvent-containing air in high Concentrations. Ambient air enters the dryer and is with the mixed solvent-containing air in the dryer interior. The air mixture becomes the first Zone of the dryer according to EP 0 723 126 A 1 supplied again. The open flame of the Burner is thereby cooled by ambient air from the outside. After cooling the open flame through ambient air will recirculate air from inside the dryer the fresh air mixed. By means of the configuration shown here can be the Volume of the exhaust gas to any post-combustion unit not reduce significantly. In this embodiment, ambient air is used to to cool the open burner flame and undesirable compounds more organic eliminate volatile components. The residence time of the combustion mixture in the burner unit does not appear sufficient in the solution according to EP 0 723 126 A1 sized.

DE 32 07 461 A1 relates to a method and an apparatus for drying and subsequent cooling of printed in particular by the offset printing process Webs. The invention relates to a method according to the Offset printing process. After the contactless drying of the printed web The web is guided in S- or Z-train over several cooling rollers. It is through Moistening of the jacket of the first cooling roller under the web side, the first is cooled, an easily cleavable water film between the web and roll shell brought. This measure causes the physical contact of the web with this and the other cooling rollers not soft thermoplastic ink is split. The inclination of the web to form waves across the Passage direction is reduced because the cleavage of the water film as a result of their different thickness in the printed and the non-printed and therefore strong dried areas leads to a uniform moisture distribution.

In the solution according to DE 197 10 124 A1 a method and a device for Temperature control of cooling rollers disclosed. This solution relates to a method and a device for cooling a printed or coated material web, which was printed in particular after the offset printing process and consists of paper. The Material web has passed a heating zone after applying paint and is over a Variety of cooling rollers led to a chill roller stand. Here is the flow of Cooling medium through the cooling rollers of a chill roll stand by two different Cooling circuits produced different temperature levels and contrary to Web running direction of a material web directed over the cooling rollers.

Also in this solution, the chill roll stand is separate from the upstream dryer the rotary printing machine arranged.

The known dryer / chill roll stand configurations show separate ones Dryer housings and separate housings for chill rolls and rewet units, which are further down from the web level. These are separated arranged housing have the significant disadvantage that occurring in a housing Problems in the next, this rearranged housing, pose further problems for example, the lateral course of the web. Known chill roll stands require a relatively large footprint and thereby increase the overall length a web-fed rotary printing machine. In addition, in the known Kühlwalzenstandanordnungen from the prior art oil condensation on the Surfaces of the first cooling rolls of these chill roll stands occur.

In view of the solutions shown in the prior art and known Dryer / chill roll stand configurations and those occurring in the technical field Problems it is an object of the present invention, the Dryer / chill stand configurations inherent disadvantages such as Color composition, lateral bleeding of the material web and the condensation problem largely turn off.

Another object of the present invention is to be seen in the overall length reduce a rotary printing press. Another object of the invention is to be seen in it, to avoid the operator of a roller rotation of the Post evaporation.

Finally, to be achieved by means of the inventive solution that the orientation one of the chill roll stand downstream folder independent of the rest Rotary printing machine components remains.

According to the present invention, these objects are achieved by a dryer for a Material web, on the surface of which paint is applied, with the characteristics of Claim 1 and by a method for drying an at least one side printed Material web with the features of claim 11 solved.

As the material web such as a printed paper web, both sides are printed, now no longer between dryer and chill roller stand the Conditions exposed to the surrounding atmosphere, the adhesion of Boundary layers of cold air can be prevented on both sides of the material web. To this , Way can be air cushion between the cooling roller surfaces and this Avoid contacting sides of the web, thereby continuing the oil condensation is excluded. Furthermore, can be by means of the inventive arrangement the Avoid soot at the dryer outlet, as the dryer exit no longer with the surrounding atmosphere, since the chill roll stand according to the present Invention is integrated in the dryer housing. Fresh air passing through the dryer integrated cooling and conditioning unit continues to contribute to the re-evaporation within the combined dryer / chill roll conditioner assembly.

In further embodiments of the present invention, the dryer may be a heating zone, a Evaporating zone and a cooling zone include, which may be separated from each other or wherein the heating zone and the evaporation zone are combined with each other and only separated from the cooling section. In each of these zones are corresponding upper and lower blowers arranged which conditioned air, for example Burner units supplied heating air and emerging from the nozzle bar circulating air, again to the nozzle bars, which extend through the zones of the dryer, lead back. In advantageous process air guidance method according to the present invention hereafter referred to as process air and hot air ducting methods, which are suitable, a dryer according to the present invention, either in countercurrent or operate in Gleichstromluftführungsprinzip.

According to a method for treating a material web according to the present Invention run the interconnected methods of heating, the Evaporating, cooling and cooling to a chill roll stand all in one common housing, which from the surrounding ambient atmosphere is encapsulated. A in the inventive arrangement of a combined Trockners / Kühlwalzenstandgehäuses entering web has at its entry in essentially the same entry parameters compared to their exit parameters such as For example, the lateral position of the web, the temperature level and the moisture content.

With reference to a drawing, the invention will be described in more detail below.

Fig. 1

eine Trockner/Kühlwalzenstandanordnung gemäß der vorliegenden Erfindung, wobei eine Brennereinheit beispielsweise außen am Trockern/Kühlwalzenstandgehäuse angebracht ist,

Fig. 2

ein Luftführungsschema innerhalb eines Trockners gemäß der vorliegenden Erfindung, wobei Prozeßluft durch eine der Trocknersektionen geleitet wird,

Fig. 3

ein Luftführungsschema eines Trockners gemäß der vorliegenden Erfindung, wobei der Trockner nach dem Gegenstromprinzip betrieben wird, und

Fig. 4

schließlich ein Luftführungsschema für eine Trockner gemäß der vorliegenden Erfindung der im Gleichstromprinzip betrieben wird.

It shows:

Fig. 1

a dryer / chill roll stand assembly according to the present invention, wherein a burner unit is mounted, for example, on the outside of the dryer / chill roll stand housing,

Fig. 2

an air routing scheme within a dryer according to the present invention wherein process air is passed through one of the dryer sections;

Fig. 3

an air guide scheme of a dryer according to the present invention, wherein the dryer is operated according to the countercurrent principle, and

Fig. 4

Finally, an air guide scheme for a dryer according to the present invention is operated in the DC principle.

FIG. 1 shows a dryer / chill roll stand configuration according to the present invention Invention, wherein on the outside of the dryer, a burner unit is housed.

In the example given here, a dryer 1 comprises a first section 1.1, as well as a second section 1.2 and a third section 1.3. Immediately behind the third section 1.3 If a cooling / conditioning unit 2 is arranged, said first section is called the Heating zone referred to in a dryer, in which the nozzles 14.1 heating air 19 is supplied becomes. Said second section is called the solvent evaporating section within Considered a dryer in which the highest concentration of solvents prevails and the highest negative pressure gradient exists. The third section 1.3 of a Dryer 1 is the cooling zone called section, in which however still Temperatures higher than 150 ° C occur. Behind the cooling section 1.3 is directly one Cooling / conditioning unit 2 integrated into the housing of the dryer 9, in which the - Material web, such as a printed paper web, a substantially vertical oriented trajectory, indicated by the reference numeral 26th

In the arrangement according to FIG. 1, a burner unit 3 is outside the dryer housing 9 arranged and may, if necessary, contain a Nachverbrennungseinrichtung and a corresponding heat exchanger 8, which is indicated here only schematically and on the right side of the burner unit 3 in Fig. 1 finds. Above the burner unit 3 a gas supply 4 is arranged, wherein the burner unit 3 has two hot air outlets 5 contains, are passed through which hot air 20 into the interior of the dryer housing 9 can. Within the burner unit 3, a pipe 7 is arranged, which is a recirculation the combustion gases allowed. The housing 9 of the dryer 1 comprises a Dryer inlet 10 and a dryer outlet 11, wherein the dryer outlet 11 in FIG. 1 illustrated embodiment extends substantially in the vertical direction and at the outlet of the cooling / conditioning unit 2 integrated in the dryer housing is arranged. Alternatively, the web, the cooling and conditioning unit 2 in leave horizontal direction after appropriate deflection. The material web, the can be printed on both sides, the dryer housing 9 passes substantially in the horizontal material conveying plane 11 extending between upper Nozzle bar 14 and lower nozzle bar 15. In the example shown in FIG Hot air 20 from the burner unit 3 exiting into the first section 1.1 via Hot gas outlet 5 passed into the heating zone 1.1.

Within the dryer housing 9 a number of upper blower 16 are added. One first upper fan 16.1 leads hot air 19 to the area of the upper Nozzle bar rows 14.1, which extend through the first dryer section 1.1. Within the following dryer section 1.2 another upper fan 16.2 is arranged, which return air 21 is supplied. Hot air 20.1 with a higher Temperature level of about 800 ° C is supplied to the first blower 16.1 and from this the upper nozzle bar rows 14.1 of the first dryer section 1.1 fed. The highest solvent concentration and the highest negative pressure gradient prevails in the Evaporation section 1.2 of the dryer 1 before. In the present example, the first Drier section 1.1 and the subsequent second dryer section 1.2 by means of a Separating element 30 separated from each other, but this has openings for the passage of Connecting tubes 28 and 29 and openings around the return air 21 the Overflow from the first section 1.1 into the downstream second section 1.2 due to allow the pressure gradient. Behind the second dryer section 1.2 is a third Drum section 1.3 provided. In the third dryer section 1.3 are two fans added. An upper third blower 16.3, the fresh air 18 with Ambient air parameters is supplied and a part of the return air 21, as Cooling zone to be regarded third dryer section 1.3 is supplied. By means of a further provided blower 16.4 is return air 21 from the upper Nozzle bar row 14.2 of the second dryer section 1.2 of the exhaust pipe 6 fed to the optionally an afterburner can be arranged downstream. Return air 21 of the nozzle bar row 14.3 of the cooling zone of the dryer, i. e. Section 1.3 is used by the connecting tubes 28, 29 passed to the first dryer section 1.1.

Thus, cleaning air 22, previously the return air 21 of the evaporation zone i. e. of the Dryer section 1.1 was, either the optional one Afterburner be supplied or directly into the exhaust pipe itself reach. As for the dryer sections 1.1, 1.2 and 1.3 with respect to the upper Jetbar rows 14.1, 14.2 and 14.3 are essentially the same for the lower ones Nozzle rows 15.1, 15.2 and 15.3 are valid and therefore do not require repetition. In the same Way are in the lower dryer half also a first, second, third blower provided, designated 17.1, 17.2 and 17.3, also the individual dryer sections assigned.

Behind the dryer section 1.3, a cooling and conditioning unit 2 is integrated into the housing of the dryer 9. The material leaving the third zone 1.3 of the dryer material web enters directly from the dryer in the cooling and conditioning unit 2, without the ambient air outside the dryer housing 9 have been exposed. The material web, which leaves the cooling and conditioning unit 2 of the dryer 1 at the outlet 11, there has the web parameters 33, a temperature of about 30 ° C and a moisture content of 4% H ₂ O. This corresponds essentially to the same entry conditions 32, with the material web enters the dryer, namely at the inlet of the dryer has a temperature of 30 ° C, but has a slightly higher moisture content of about 6% H ₂ O. 1, the last of the cooling rolls 27 may have a separate drive unit 23 in order to ensure a correct inlet of the web leaving the cooling and conditioning unit 2 into the downstream turning bar superstructure.

Thanks to the immediate entry of the web in the cooling and conditioning unit 2 is Oil condensation on the surfaces of the first cooling rolls prevented, since no distance between the dryer outlet and the inlet and the cooling and conditioning unit 2 occurs. The occurrence of after-evaporation can in the housing 9 of the cooling and Lay conditioning unit 2 laid, as continuously fresh air 18 passed through this is, which promotes the evaporation inside the housing 9, so that the Rotation-handling staff no after-evaporation and of volatile components is exposed to evaporating solvent.

Further, by combining the related processes of drying, cooling, and rewetting a web within a housing, process control can be maintained so that the web specifications at the entrance to and exit from the housing are substantially coincident. Thus, the temperature of the material web at the inlet has approximately the same value as at the outlet 11 (about 30 ° C); Finally, the moisture content of the material web of 6% H ₂ O at the dryer inlet about the same level as the moisture content of the web at the dryer outlet 11. Another with the inventive Configuration accompanying advantage is that by integrating the cooling and conditioning unit 2 in the housing 9 of the dryer, the length of a rotation can be kept much shorter, so that much less footprint is consumed within a printing operation.

FIG. 2 shows an air routing scheme within a dryer according to the present invention. FIG Invention, wherein process air is passed around a section of the dryer.

In this configuration, hot gas 20 and process air 18 by means of Blower assembly 16.3, 17.3 within the dryer section 1.3 by the Connecting tube system 28, 29 led to the dryer section 1.1. The Connecting tube system 28, 29, for example, within the dryer housing. 9 be included. Hot gas 20 can also be supplied to the first dryer section 1.1 can be seen, as can be seen in the air guide scheme of FIG. By means of this schematically reproduced fan assemblies 16.1, 17.1, the hot gas 20 and the air gas mixture, which via the connecting tube system 28, 29 in the first Dryer section is led to nozzle rows, which are on both sides of the Bahntransportebene are arranged and a floating transport this Allow material webs. Return air 21 of the nozzle rows in the first Drier section 1.1 is an evaporation section 1.2 through an opening in the Separator 30 is supplied, which between the first and the second Drum section 1.1 or 1.2 may be provided. Alternatively, the Separator 30 are also omitted to allow unimpeded overflow of the Return air 21 of the nozzle rows of the first dryer section 1.1 in the To ensure evaporation section 1.2 of the dryer 1. In the second section 1.2 of the Drier 1, that is, the solvent-expelling section 1.1, has the highest negative Pressure gradient before and there is the highest solvent concentration prevailing. For this reason, the second section 1.2 of the dryer 1 is an exhaust pipe 6 assigned to the exhaust of an optional predictable afterburning unit outside to feed the dryer.

The fan assembly 16.2 or 17.2 within the second dryer zone 1.2 distributes the Return air 21 to the corresponding nozzle row sections within the Solvent expelling section 1.2, already in connection with FIG. 1 briefly has been described.

Fig. 3 shows an alternative air guiding scheme within a dryer according to the present invention, wherein this is operated in the counter-current mode.

As has already been described in connection with FIG. 2, hot gas 20 becomes a Burner unit 3 and process air 18 a fan pair 16.3, 17.3 within the third Dried section 1.3 supplied. Return air 21 is then in countercurrent principle with respect on the web transport direction of the third dryer section 1.3 through the Evaporating zone 1.2 of the dryer transported to the heating zone 1.1. The Blower arrangements 16.3, 17.3; 16.2, 17.2; 16.1, 17.1 will be hot gas 20 respectively individually supplied. During the passage through the various Dryer sections 1.1, 1.2 and 1.3, the return air 21 is gradually solvent-containing, especially within the evaporation zone 1.2. Because the highest Solvent concentration of the air in the dryer with countercurrent principle within the first section of the dryer 1.1 is reached, an exhaust pipe 6 of the zone 1.1 assigned to the solvent-laden exhaust gases of a post-combustion device feed inside or outside the dryer.

Due to the between the cooling section 1.3 and the evaporation section 1.2 prevailing pressure difference is in the embodiment of FIG. 3 between them Zones a separating element 31 is provided. Within this partition element 31 is a Opening provided to an inflow of return air 21 in the To allow evaporation section 1.2. The separating element 30, which in Fig. 3 is shown and the first and the second dryer section separates from each other is not absolutely necessary to separate the sections from each other, it can also be omitted become.

Finally, FIG. 4 shows an air guiding scheme for a dryer according to the present invention Invention which operates in DC mode.

In this configuration, hot gas 20 and ambient air 18 from the outside of the first Drum section 1.1 supplied. Within the first dryer section 1.1, so the Heating zone, a fan assembly 16.1, 17.1 is arranged, which is a distribution ensures the hot gas-air mixture in the web running plane. Return air 21 of the said fan assembly 16.1, 17.1 is passed into an evaporation section 1.2 by an optionally providable separating element 30. This separating element 30 can also be omitted to allow a free flow of the return air 21 in the To ensure evaporation section 1.2 of the dryer 1.

From the evaporation section 1.2 of the dryer, return air 21 now passes solvent-based due to the evaporation process taking place there in the Drier section 1.3, which by means of a separating element 31 of the said Evaporation section 1.2 of the dryer 1 is separable. During their transport through the various dryer sections 1.1, 1.2 and 1.3, the return air 21 more and more solvent-containing, with their highest solvent concentration in the last Zone 1.3 is reached. Consequently, an exhaust pipe 6 of this third dryer section 1.3 associated, which by means of a previously mentioned separation element 31 of the Evaporation zone 1.2 of the dryer separated because of the high pressure difference can be.

In the configuration of FIG. 4, the air guide is substantially parallel to Web running direction held. All three sketched here only schematically Air guidance schemes have the advantage that the fresh air flow through the cooling and Conditioning unit 2, which is arranged downstream of the dryer and integrated into its housing 9 is, to a further after-evaporation within the cooling and conditioning unit. 2 contributes, regardless of whether the process air stream 18 this cooling and Conditioning unit 2 in an upper portion or in a lower portion passes.

LIST OF REFERENCE NUMBERS

1

dryer

1.1

first section

1.2

second section

1.3

third section

2

Cooling and conditioning unit

3

burner

4

gas supply

5

Hot gas outlet

6

exhaust pipe

7

pipe

8th

heat exchangers

9

casing

10

dryer inlet

11

dryer outlet

12

Rail running plane

13

Web direction

14

upper nozzle row

14.1

upper nozzle section

14.2

upper nozzle section

14.3

upper nozzle section

15

bottom nozzle row

15.1

lower nozzle row section

15.2

lower nozzle row section

15.3

lower nozzle row section

16

top blowers

16.1

upper first blower

16.2

upper second blower

16.3

Upper third blower

16.4

Upper cleaning air blower

17

bottom fan

17.1

lower first blower

17.2

lower second blower

17.3

lower third blower

17.4

under cleaning air blower

18

fresh air

19

hot air

20

Hot air from the burner

20.1

Hot air with a higher temperature level

20.3

Hot air with lower temperature level

21

Return air

22

cleaning air

23

drive

24

first chill roll

25

Wiederbefeuchtungseinheit

26

Web running path

27

chill rolls

28

upper connecting tube

29

lower connection tube

30

separating element

31

separating element

32

Web inlet parameters

33

Web outlet parameters

34

chill rolls

Claims (12)

1. Dryer (1) for a material strip, onto the surface of which dye has been applied, with a housing (9) divided into sections (1.1, 1.2, 1.3), incorporating a number of blowers (16.1, 16.2, 16.3, 16.4, 17.1, 17.2, 17.3, 17.4), and which includes a strip transport level (12) at which the material strip is transported, whereby a cooling and conditioning unit (2) is located directly behind a last section (1.3), which includes one or more cooling cylinders (27) over which the material strip (32) is routed, characterised in that the cooling and conditioning unit (2) is integrated into the housing (9) in such a way that fresh air (18) is introduced into the housing (9) by the cooling and conditioning unit (2) via one of the blowers (16.1, 16.3, 17.1, 17.3), whereby a post-evaporation of solvents is supported within the cooling and conditioning unit (2).
2. Dryer according to Claim 1, characterised in that the sections of the housing (9) incorporate a heating section (1.1) and an evaporation section (1.2) as well as a cooling section (1.3), whereby the cooling and conditioning unit (2) is positioned after the cooling section (1.3) when viewed in the strip transport direction (13) of the material strip.
3. Dryer according to Claim 2, characterised in that the fresh air (18) is introduced into the heating section (1.1) around the evaporation section (1.2).
4. Dryer according to Claim 3, characterised in that the fresh air (18) is introduced via connecting pipes (28, 29) of the heating section (1.1).
5. Dryer according to one of the Claims 2 to 4, characterised in that hot air (20.1) with a higher temperature level is introduced into the heating section (1.1), and/or hot air (20.3) with a lower temperature level introduced into the cooling section (1.3) of the dryer (1).
6. Dryer according to one of the preceding Claims, characterised in that the air supply within the dryer (1) flows in a direction against the strip transport direction (13) through the sections (1.1, 1.2, 1.3).
7. Dryer according to Claim 6, characterised in that the return air (21) between the sections (1.1, 1.2, 1.3) of the dryer (1) is exchanged against the direction of the strip transport direction (12).
8. Dryer according to one of the preceding Claims 1 to 5, characterised in that the return air (21) between the sections (1.1, 1.2, 1.3) is exchanged in the strip transport direction (13).
9. Dryer according to one of the preceding Claims, characterised in that a first one of the cooling cylinders (27) over which the material strip is guided is located near the outlet of the dryer (1).
10. Dryer according to one of the preceding Claims, characterised in that the cooling cylinders (27) are not equipped with inserts for the deflection of cooling medium flowing through the same on their insides.
11. Method for the drying of a material strip printed on at least one side, with the following process stages:

    guiding of the strip along a strip transport level (12) through a dryer (1) with a housing (9) divided into sections (1.1, 1.2, 1.3) and incorporating a number of blowers (16.1, 16.2, 16.3, 16.4, 17.1, 17.2, 17.3,17.4),

    guiding of the strip over one or more cooling cylinders (27) of a cooling and conditioning unit (2) located directly behind a last section (1.3),

    characterised by the process stages of:

    envisaging the cooling and conditioning unit (2) as a cooling and conditioning unit (2) that is integrated into the housing (9),

    intake of fresh air (18) via one of the blowers (16.1, 16.3, 17.1, 17.3) through the cooling and conditioning unit (2) into the housing (9), whereby a post-evaporation of solvents is supported within the cooling and conditioning unit (2).
12. Method according to Claim 11, characterised in that the strip inlet parameters (32) of the material strip, especially the temperature and/or the moisture content at the dryer inlet (10) substantially match those of the strip parameters (33) at the dryer exit (11).

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