WO2016096202A1

WO2016096202A1 - Device for paper drying and method for cleaning it

Info

Publication number: WO2016096202A1
Application number: PCT/EP2015/074345
Authority: WO
Inventors: RainerKlaus PUMPE
Original assignee: Voith Patent Gmbh
Priority date: 2014-12-16
Filing date: 2015-10-21
Publication date: 2016-06-23
Also published as: CN107208374B; EP3234258A1; CN107208374A

Abstract

Nozzle channel (1) for applying a gaseous medium to a web-shaped material, in particular a paper, cardboard, tissue or pulp web, comprising a channel body (2) which has a multiplicity of nozzles (3), and guide plates (4, 4a) which are provided in the interior of the channel body (2), wherein means are provided in the nozzle channel (1) by way of which means at least some, preferably all guide plates (4, 4a) can be removed in a simple way from the nozzle channel 1 and can be inserted again. Drying hood for use in a machine for drying a web-shaped material, in particular Yankee hood, wherein the drying hood has at least one, preferably a plurality of nozzle channels (1) according to the invention. Method for servicing a nozzle channel (1) or a drying hood, which method comprises the steps: removal of guide plates (4, 4a) from the channel body (2) through the at least one end-side opening (5), servicing of the nozzle channel (1) through at least one end-side opening (5), introduction of the guide plates (4, 4a) into the channel body (2) through the at least one end-side opening (5).

Description

Apparatus for drying paper and process for its cleaning

The invention relates to a nozzle channel (1) for applying a gaseous medium to a web-shaped material, in particular a paper, board, tissue or pulp web according to the preamble of claim 1, a drying hood for use in a machine for drying a web-shaped material according to the preamble of claim 8, a method for servicing a nozzle channel according to claim 1 1 and a method for maintenance a drying hood according to claim 13.

In the manufacture of many web-like materials, particularly in the production of paper, board, tissue or pulp webs, these webs must undergo at least one drying step during the manufacturing process. As a rule, the material web is guided over steam-heated cylinders. In some applications, for example in the drying of tissue webs so-called Yankee cylinders are used. These cylinders have a large diameter of 2m and more. In addition, these cylinders comprise drying hoods, the task of which is to apply a hot gas, in particular hot air, to the material web. The hot gas is usually passed into nozzle channels. These nozzle channels distribute the gas across the width of the web. In this case, the problem arises that it comes with an uneven distribution of the gas to a non-uniform drying of the web and thus quality losses thereof. To remedy this problem, the prior art, e.g. US 2001/0054239 A1 discloses that these nozzle channels can have internals that even out the gas distribution and thus the temperature profile.

Furthermore, it is known from WO 2006/057696 that these internals can have the form of baffles. These baffles are mounted in the nozzle channel, eg welded, and the shape of the baffles, the gas stream can be distributed over the length of the nozzle channel accordingly. In the long-term operation of such drying devices, however, shows that attach to the nozzles of the nozzle channel impurities, for example by fibers. This will eventually lead to complete or partial blockage of these nozzles. Since this again the uniformity of the web drying can be disturbed, the nozzles or the nozzle channels must be cleaned or maintained regularly. However, this is very difficult in the case of the nozzle channels according to WO 2006/057696 or US 2001/0054239 A1, since access via the supply channels of the gas is generally hardly possible, and lateral access from the front ends of the nozzle channels the fixtures and baffles is obstructed.

The object of the present invention is therefore to provide a drying device which ensures a distribution of the gas and thus a control of the temperature profile over the width of the material web and still allows easy maintenance of the nozzle channels.

This object is fully achieved by a nozzle channel according to the characterizing part of claim 1, a drying hood according to the characterizing part of claim 8, a method for maintaining a nozzle channel according to claim 1 1 and a method for maintaining a drying hood according to claim 13.

The nozzle channel according to the invention for applying a gaseous medium to a web-shaped material, in particular a paper, board, tissue or pulp web, comprises a channel body, which has a plurality of nozzles, and baffles, which are provided in the interior of the channel body.

According to the invention, means are provided in the nozzle channel with which at least some of the baffles, preferably all baffles in a simple manner from the

Nozzle channel can be removed and replaced.

The baffles are therefore not in the nozzle channel according to the invention with the

Channel body welded or otherwise firmly connected. In this way, the baffles for maintenance can be easily removed from the nozzle channel, whereby a maintenance of the nozzle channel is simplified. After completion of the maintenance work, the baffles can again be easily inserted into the nozzle channel.

The gaseous medium may be, for example, hot air. In advantageous embodiments, the temperature of the gaseous medium can be above 100 ° C., in particular above 200 ° C., advantageously even above 300 ° C. Usually, the baffles consist mainly of metal, especially steel. Within the scope of this application, however, the term baffles should also be understood to mean guide elements made of other suitable materials. For this purpose, for example, polymer materials come into question, fiber-reinforced plastics, or ceramics.

Advantageously, the material of the baffles is chosen so that it remains stable even with permanent contact with the hot gaseous medium.

Further advantageous embodiments of the invention are described in the subclaims.

It can be provided, for example, that the baffles are positively but reversibly connected in a simple manner with the channel body. In particularly advantageous embodiments, the baffles are connected via a clamping connection with the channel body.

In an advantageous embodiment of the nozzle channel, the channel body has on at least one of its end faces, preferably on both end faces depending on an opening through which at least some, preferably all baffles can be easily removed from the nozzle channel and reused.

Furthermore, it can be provided that in each case a closure lid is provided on at least one end face, preferably on both end faces. These Cover caps are used to seal the frontal openings. This prevents gas from leaking out of the front-side openings during operation of the nozzle channel, but nevertheless allows the guide plates to be removed via the front-side openings and replaced again for maintenance.

In a particularly advantageous embodiment of the invention, the means for easy removal of the baffles comprise at least one common carrier element. At least one guide plate preferably has a plurality of guide plates, particularly preferably all guide plates are connected to this common carrier element.

Depending on the design baffles may be rigidly or movably connected to the common carrier element.

The common carrier element can be, for example, a rod, a tube or a strip, or the common carrier element can comprise one or more such components.

Also, the common carrier element is usually not firmly welded to the channel body.

The common carrier element is advantageously designed so that it can be easily reached or gripped by an end opening. By pulling out of the common support member through the frontal opening can thus easily remove all associated baffles in a simple manner from the nozzle channel. In the same way, the baffles can be reused in the nozzle channel after maintenance.

To simplify the work, it will generally be advantageous to fasten all baffles to a common carrier element. Such a carrier element extends substantially over the entire length of the nozzle channel. However, several common carrier elements may be provided. Thus, it may be advantageous in individual cases to provide two common carrier elements, wherein each of these carrier elements substantially over half the length of the nozzle channel extends. For maintenance, the one common support element can then be removed through the one end opening, and the other common support element through the other end opening. In further advantageous embodiments, a part of the baffles preferably all baffles may be designed as bulkhead plates. Through such bulkhead plates, the nozzle channel over its length - that is, across the width of the material web - is divided into individual segments. Furthermore, the invention relates to a drying hood for use in a machine for drying a web-shaped material, in particular a paper, cardboard, tissue or pulp web. For example, it can be a Yankee hood, as used, for example, in the production of tissue papers. The drying hood according to the invention is characterized in that it comprises at least one, preferably a plurality of nozzle channels according to any one of claims 1-7.

In an advantageous embodiment of the drying hood according to the invention it can be provided that the drying hood comprises a main feed channel and at least one, preferably two or more distribution channels. Through the main feed channel while the hot gas is passed into the drying hood, and over the distribution channels or the distribution of the gas to the various nozzle channels.

In a particularly preferred embodiment, the at least one distribution channel is designed in a curved shape.

Furthermore, the invention relates to a method for the maintenance of a nozzle channel according to any one of claims 2 to 7. The method comprises the process steps:

a) removing baffles through the at least one end face

Opening from the channel body b) Maintenance of the nozzle channel through at least one frontal opening c) introducing the baffles through the at least one end opening in the channel body

The nozzle channels can be maintained in the installed state by means of the method according to the invention. You do not have to do this from their installation situation, e.g. be removed from the drying hood.

If closure lids are provided in the nozzle channel, they are usually removed to the extent that at least one frontal opening is exposed before the process step a), so that the guide plates can be removed by them.

If a common carrier element is provided, this is advantageously designed so that it can be easily reached or gripped by a frontal opening. In process step a), for example, by pulling out the common carrier element through the frontal opening, all associated guide plates can be easily removed from the nozzle channel. In the same way, in step c) the baffles can be reused in the nozzle channel after the maintenance work. The maintenance in process step b) may comprise or consist of the cleaning of some or all nozzles of a nozzle channel in an advantageous embodiment of the method.

Finally, the invention relates to a method for the maintenance of a drying hood. The drying hood is embodied according to one of claims 8-10 and the method for maintenance of the drying hood comprises the maintenance of at least one nozzle channel, which takes place by means of a method according to one of claims 11 or 12. In the following, the invention will be explained with reference to schematic, not to scale figures further. Figure 1 shows schematically a longitudinal section through a nozzle channel with bulkhead plates according to the prior art

Figure 1 b shows schematically a longitudinal section through a nozzle channel with baffles according to the prior art

Figure 2 shows schematically a longitudinal section through a nozzle channel according to the invention with bulkhead plates

Figure 2b shows schematically a longitudinal section through a nozzle duct according to the invention with baffles, one of which is designed as a partition plate.

FIG. 3 shows a cross section through a nozzle channel according to the invention.

FIG. 4 shows a section through a drying hood.

In FIGS. 1 and b, sections along the length L of a nozzle channel 1 according to the prior art are respectively described. The nozzle channel 1 in each case comprises two supply lines 9 for a hot gas from distribution channels 9. The gas exits the nozzle channel 1 through the nozzles 3 and is applied to the material web. The baffles 4, 4a are designed in the nozzle channel 1 shown in Figure 1 as partition plates 4a. These bulkhead plates 4a are firmly connected to the channel body 2. As a rule, these partition plates 4a are welded to the channel body 2. Figure 1 b shows a nozzle channel 1, in which in the middle of a partition plate is firmly welded to the channel body. In addition, the nozzle channel 1 but also provided with further baffles 4, which distributes the flow, which enters from the supply lines 9 in the nozzle channel 1, over the length L of the nozzle channel 1. These baffles 4 are firmly connected to the channel body 2.

A maintenance of the nozzle channel 1, especially the cleaning of the nozzles 3 is possible in the cases shown in Figure 1 and 1 b only on the access of the leads 9 and is further complicated by the baffles 4, 4a.

FIG. 2 and FIG. 2 b each show a nozzle channel 1 according to the invention. Here, too, the supply of gaseous medium, preferably hot air, takes place through feed lines from distribution channels 9. The gas exits the nozzle channel 1 through nozzles 3 and is applied to a material web such as a tissue web, a pulp web or the like. The nozzle channel 1 shown in FIG. 2 comprises by way of example four guide plates 4, 4a, all of which are designed as partition plates 4a are. Depending on the application, especially depending on the length L of the nozzle channel 1 and the number of distribution channels 9, more or fewer baffles may be provided. The bulkhead plates 4a are not fixedly connected to the channel body 2 in FIG. In particular, they are not welded or screwed to the channel body 2. Instead, it may be provided that the partition plates 4a are inserted into the nozzle channel 1 in a form-fitting manner or with little play. The bulkhead plates 4a are all attached to a common carrier element 7. The carrier element 7 comprises in FIG. 2 a tube, especially a steel tube, which is located approximately in the middle in the nozzle channel. However, it is also possible for the common support element 7 to comprise or consist of a rod or a strip. The common carrier element 7 extends in the example shown in FIG. 2 over the entire length L of the nozzle channel 1. However, it can also be provided according to the invention that the carrier element extends only over part of the length L. For example, it is also conceivable that two common support elements 7 are provided, each extending over one half of the length L.

The nozzle channel 1 shown in FIG. 2 b comprises by way of example five guide plates 4, 4 a, of which one is designed as partition plates 4 a, and the others as guide plates 4. The common carrier element 7, with which the partition plate 4a and the usual baffles are connected, here extends by way of example only over a part of the length L of the nozzle channel 1, but may extend in other embodiments over the entire length L. The common carrier element 7 is eccentrically mounted in the nozzle channel 1 in Figure 2b. It can also be provided according to the invention that the common carrier element 7 or parts thereof, is provided on the wall of the channel body 2 or near the wall.

The nozzle channels 1 from FIGS. 2 and 2 b have end-side openings 5 on both end faces, which are each closed by a closure lid 6. In other advantageous embodiments, it can also be provided that the nozzle channel 1 has an end-side opening 5 only at one end face. By opening the closure lid 6, the frontal opening 5 can be exposed. For maintenance of the nozzle channel 1, especially for cleaning the nozzles 3 can then the guide plates 4, 4 a are removed from the nozzle channel 1 through an end opening 5. It is expedient to attach the common carrier 7 so that it can be gripped by the frontal opening 5. There is then the possibility of pulling the common carrier 7 together with the guide plates 4, 4 a fastened thereto together from the nozzle channel 1 or to remove it.

The baffles 4, 4 a, or especially the partition plates 4 a, according to the invention can be rigidly connected to the common carrier element 7. However, it can alternatively also be provided that the sheets 4, 4a are movably connected to the carrier element. Thus, it may be advantageous to provide the plates 4, 4a with a folding mechanism to allow easier removal or insertion into the nozzle channel.

FIG. 3 shows a cross section through a nozzle channel 1 according to the invention. A partition plate 4a extends substantially over the entire cross-section of the channel body 2 and subdivides it therewith. As a common support member 7, a rod is provided here by way of example, which is mounted in the middle of the channel body 2. With this common support element, the baffles are rigidly fixed in this example.

FIG. 4 schematically shows a section through a possible embodiment according to the invention of a drying hood, especially a Yankee hood. It comprises, in addition to the main supply channel 10, two distribution channels which are bent, in the form of so-called .crescent headers. These distribution channels 9 distribute the gaseous medium to the individual nozzle channels. 1 In this case, at least one nozzle channel 1, preferably all nozzle channels 1, is designed as a nozzle channel 1 according to the invention.

Claims

claims

Nozzle channel (1) for applying a gaseous medium to a web-shaped material, in particular a paper, board, tissue or pulp web, comprising a channel body (2) having a plurality of nozzles (3), and baffles (4,4a ), which are provided in the interior of the channel body (2), characterized in that in the nozzle channel (1) means are provided with which at least some, preferably all baffles (4,4a) in a simple manner from the nozzle channel (1) and can be used again.

Nozzle channel (1) according to claim 1, characterized in that the

Channel body (2) has at least one of its end faces an opening (5) through which at least some, preferably all baffles (4,4a) in a simple manner from the nozzle channel (1) can be removed and replaced.

Nozzle channel (1) according to one of the preceding claims, characterized in that at least one end face, preferably at both end faces in each case a closure cover (6) is provided.

Nozzle channel (1) according to one of the preceding claims, characterized in that the means for easy removal of the guide plates (4,4a) comprise at least one common carrier element (7), and at least one guide plate (4,4a), preferably a plurality of guide plates (4,4a) , 4a), particularly preferably all guide plates (4, 4a) are connected to a common carrier element (7).

Nozzle duct (1) according to claim 4, characterized in that at least part of the guide plates (4, 4a), preferably all guide plates (4, 4a) are rigidly or movably connected to the common carrier element (7).

6. nozzle channel (1) according to any one of claims 4 or 5, characterized in that the common carrier element (7) comprises a rod, a tube or a strip or consists thereof. 7. nozzle channel (1) according to one of the preceding claims, characterized in that at least a part of the guide plates (4,4a), preferably all guide plates (4,4a) are designed as partition plates (4a), through which the nozzle channel (1) in Segments (8) is divided. 8. drying hood for use in a machine for drying a web-shaped material, in particular Yankee hood characterized in that the drying hood at least one, preferably a plurality of nozzle channels (1) according to one of claims 1-7. 9. drying hood according to claim 8, characterized in that the

Drying hood a Hauptzuführkanal (10) and at least one, preferably two or more distribution channels (9).

10. drying hood according to claim 9, characterized in that the at least one distribution channel (9) has a curved shape.

1 1. Method for the maintenance of a nozzle channel (1) according to one of Claims 2-7, characterized in that the method comprises the steps of: b) removing guide plates (4, 4a) from the channel body (2) through the at least one frontal opening (5) c) Maintenance of the nozzle channel (1) by at least one end opening (5) d) Introduction of the guide plates (4, 4a) through the at least one end opening (5) into the channel body (2). 12. Method according to Claim 1 1, characterized in that the maintenance of the nozzle channel (1) comprises or consists of the cleaning of some or all nozzles (3).

13. A method for the maintenance of a drying hood, characterized in that the drying hood according to one of claims 8 - 10 is executed, and the method for maintenance of the drying hood comprises the maintenance of at least one nozzle channel, which by means of a method according to any one of claims 1 1 or 12 takes place ,