DE1031115B - Device for drying a movable material, in particular paper web - Google Patents

Description

The invention relates to a device for drying a material, in particular a paper web, which is continuously moved on lying on the jacket of a rotating cylinder. Such cylinder dryers are known. They partly consist of a hood that partially encompasses the cylinder Enclosing cavity which is essentially concentric against the cylinder through a to the cylinder jacket lying and to this arranged at a small distance inner surface is delimited, which mainly consists of the perforated bottoms of arranged side by side in alternating sequence in the axial direction of the cylinder, for blowing hot air against the material web or for its subsequent suction Channels consists, the length of which is equal to that of the cylinder.

However, these known dryers generally have the disadvantage that they do not distribute the air uniformly and thus do not guarantee even drying of the material web. This is in the Mainly due to the fact that the arranged in the hood or arranged on this pressure and Suction chambers have unequal size or position to the perforated bottoms of the channels. Also own This dryer has the further disadvantage that due to their design, the cylinder ends and the Gap between the hood and the cylinder jacket are difficult to access, for example is of particular disadvantage for tip insertion.

The aim of the invention is to eliminate these shortcomings of the known cylinder dryers. this will achieved essentially in that the cavity enclosed by the hood through a to the axis of the rotating cylinder vertical partition is divided into two chambers of approximately the same size, by one as a pressure chamber for the hot air and the other as a suction chamber for the air to be extracted Air is used and which is alternately connected to the channels for blowing in and sucking out the air stand and are limited in the axial direction by one end face each, which corresponds to the corresponding end face of the cylinder lie essentially in one plane. Preferably, the end faces of the Hood entirely or almost entirely within the plane formed by the end faces of the cylinder, as this results in it a particularly good accessibility of the cylinder and hood is guaranteed.

The pressure channels, which are completely closed off from the cavity of the hood, are in the suction chamber and the suction channels, which are also closed, are arranged in the pressure chamber. These closed channels change within the corresponding chamber with the opposite types of open channels Device for drying

a movable material,

especially paper web

Applicant:

Bor per Valentin Leckner,
Jönköping (Sweden)

Representative: Dr.-Ing. E. Hoffmann, patent attorney,
Munich 22, Widenmayerstr. 34

Claimed priority:
Sweden 12 January 1954

Börje Valentin Leckner, Jönköping (Sweden),
has been named as the inventor

starting with the closed channels of one chamber

communicate with the open channels of the other chamber through openings in the partition.

The hood can also be attached to the radially inward

directed ends of their end faces be provided with annular sector-shaped cover plates that are attached to the end faces are easily removable. The radially inward part can be made of a soft one Fabric, such as felt or the like., Are made, which can rest against the outer edge of the cylinder, so that the space between the hood and the cylinder jacket by bending the soft fabric panels is accessible without removing the cover plates.

This means that despite the easy accessibility of the hood, it is easy to see and clean Way ensures adequate sealing and thermal insulation. As a result of the good airtightness to the outside and the effective thermal insulation, it is possible in hoods according to the invention a To reach a dew point of about 70 ° C, while with the previously known designs mostly none higher dew point than about 50 ° C.

A high dew point of the humid air is advantageous from many points of view. The water absorption capacity the air increases progressively with the increase of the dew point, and thus it becomes possible at high Dew point to work with small amounts of air, resulting in smaller dimensions for the hood and lower Consumption for the fans leads than it does for one

809 528/281

3 4

lower dew point would be possible. The higher the drums, ducts, hot air and recovery dew point the more effectively the batteries and other known ones work to operate the Anmit the hood work together in a known manner- order suitable or necessary organs, the the heat recovery units. are outside the scope of the invention are in

These and other features of the invention are not included in the drawing. However, the air can

from the following description of the in the drawing instead of through the nozzle 12 and / or 13 also through

tion illustrated embodiments. connecting elements attached in another way

Fig. 1 shows the basic principle of a machine in and derived, e.g. B. through openings in the

which is the subject of the invention preferably end faces 7 and / or 8 or any other

Can apply; OK places of the jacket 4.

2 and 3 show a hood according to the invention. The end faces 7 and 8 are essentially

dung in different oblique views for a borrowed in the same plane as the end faces of the

Yankee or self-approval paper machine; Cylinder 2 (Fig. 4 to 6). This is of great practical

Fig. 4 and 5 illustrate the subject of the table importance and facilitates the installation of the

Invention in a longitudinal section through the central hood, its manufacture and the installation of others

axis of the hood on a reduced scale; lines required for the machine, etc. and

Fig. 6 shows an enlargement of the section VI, finally, the overlook and maintenance of the machine

from Fig. 4; and the hood.

Figures 7 and 8 are cross-sections through the hood extending along the inside of the hood

according to the lines VII-VII and VIII-VIII of FIG. 4 20 side by side in an alternating sequence, injection channels

and 5 on an enlarged scale; 14 for hot air and suction channels 17 for moist air.

9 and 10 show in plan and cross section the bottoms of these channels, which in the drawing with

a device for regulating the amount of the single-rectangular cross-section are shown forming the

blowing hot air. Inner surface of the hood. The injection channels 14 are

That shown in the drawings and below 25 within the pressure chamber 11 radially outward

The embodiment described relates to an open, within the suction chamber 10 they are against it

Yankee machine (Fig. 1) in which a paper- fully closed. To supply the hot air to

track 1 moved by a cylinder 2, which is in this channel part, the partition wall 9 through the

Rotates in the direction of the arrow and about three quarters of openings 15 are broken.

its circumference is enclosed by a hood 3. 3 ° At the bottom of the injection ducts 14, ie on the part of the hot air hoods 3 facing the paper web in FIG. 1, a large number of injection nozzles 16 are attached to a cylinder 2 and this together. However, working deflecting rollers 2 α and 2 b can also be used to turn other designs of injection devices which are known to those skilled in the art, for example longitudinal slots, whereby one

The hood 3 has in cross section a sickle 35 but guide rails for the direction of the

shaped shape and consists of a jacket 4 with hot air must be arranged.

the arm-like ends 5 and 6 and the end faces 7 The suction channels 17 are mainly analogous to the and 8th jacket, arm-like ends and end faces of injection ducts 12. Inside the suction shoulders be well insulated and can for example chamber 10 they are open while they are inside the made of two parallel sheet metal layers with 40 pressure chamber 11 are completely closed. The ground The suction channels form a sheet metal 18 with perforations (Fig. 6 to 8). gen 19 for the return flow of the air. The suction

On the cylindrically shaped inner surface of the channels can from the spaces between the Hood 3 are arranged injection and suction elements, there are injection channels, with a cover 20 den which are described in more detail below. Which closes by 45 channel 17 within the pressure chamber 11, the jacket 4, the arm-like ends 5 and 6, which are used to divert the moist air from the part of the suction end faces 7 and 8 and the inner surface formed channel within the pressure chamber 11 is the separation cavity is broken through the openings 21 by means of a transverse partition 9, wall 9 into two chambers of approximately the same size 10 It is of particular importance that the walls and 11 divided, which follow the cylindrical inner surface 50 in the channels and cavities are absolutely airtight, and radially with respect to the rotating cylinder so that loss of air is avoided. The hot outside same lie. The chamber 10 is to have a relatively large static pressure in the air Sucking off the moist air is determined and is referred to as a suction chamber in the order of about 100 to 150 mm. This suction column is blown in. For the purpose of a convenient access chamber and the interior spaces connected to it are the ends of the injection ducts 14 with off of the hood are provided in the drawing with minus removable end plates 22 (FIG. 6) which are attached to signs attached to one of the duct walls in these rooms by means of screws 22 a to mark seeing negative pressure. could be. To have a sufficient seal between

The chamber 11 is to blow in hot air of the end face 8 and the walls of the channel 14

determined and is obtained in the following with pressure chamber 60, it is expedient to use a circumferential

designated. This pressure chamber and that with this welding edge 8 'to be attached.

connected spaces within the hood are in the. The seal must also be good for the suction side.

Drawing with plus sign around the in the- Leakage causes the moist air with

to mark the overpressure prevailing in the rooms, cold air entering from outside is mixed, where-

whereby the terms under- or overpressure decrease to 65 due to the dew point and the heat retention is reduced

relate to the relationship to atmospheric pressure .. worsens. The vacuum for suction in

To suck the moist air from the suction chamber of the order of 10 mm water column is

this is provided with a connection piece 12. Which are significantly lower than the overpressure for blowing in,

The pressure chamber has a similar connection piece, but the ingress of outside air must be prevented

13 for the supply of hot air. Fans, 70 become. On the jacket edges of the cylinder is on; ■

to pay attention to a particularly good seal. For this purpose, 7 and 8 z. B. by means of Screws 23 a attached cover plates 23, the extensions of the end faces up to the lateral surface 2 of the cylinder and beyond (Fig. 6). The inner edge of the cover plates 23 can be a Wear extension 23 'made of a strip of felt or a similar material, which is against the end face of the cylinder 2 presses so that a very good seal is obtained. To the inlet of the paper web slots in the hood must be arranged through into the hood and to the outlet from it which air passage is inevitable. However, this leak on the side does not affect the Uniformity of drying, in addition, the movement of the paper web counteracts at the outlet slot. At the inlet slot, the movement of the paper web causes an increase in the air flow, but that by appropriate balancing between blowing in and sucking off in the vicinity of the inlet point can be compensated.

Since hoods of this type are usually very large and extensive, it is among other things in view on the transport and installation expedient to subdivide them. The hood according to the drawing is divided into three parts by two separating surfaces 24 which run parallel to the axis of the cylinder 2. the Dividing surfaces are best placed through the suction channels 17, as FIG. 3 shows. This is the Seal easier to carry out than if you put the dividing surfaces through the pressure channels 14.

The hood is useful on one or both sides of the shell with control flaps 25 (Fig. 2) for covering of the openings 26 and 27 in the jacket 4 (FIG. 3), the opening 26 to the suction chamber 10 and the opening 27 leads to the pressure chamber 11. By arranging the flaps 25 across the dividing points one simplifies the construction and the composition, inter alia, that the Individual parts connected to one another by bolts or screws are easily accessible after removing the flaps are. The seal of the jacket can be done on the necessary sealing strips under the flap edges restrict. There are no cohesive fasteners on the outside of the jacket required for the parts of the hood.

The operation of the hood described is explained below:

The direction of air flow is indicated by arrows in the drawing. The hot air is in the Blown pressure chamber 11, from which it enters all pressure channels 14 and out of these vertically is pressed out through the nozzles 16 to form the web of material. The hot air streams hit the paper web, take it Moisture are now thrown back as moist air currents to the sides and penetrate the perforations 19 in the bottoms of the suction channels 17. From there, the moist air flows into the suction chamber 10, from which it through the connection opening 12 to an exhaust fan in connection with a Heat recovery unit, a water heater or the like is passed on in a known manner.

With hot air hoods for cross blowing, it has been a problem to dry evenly over to receive the entire railway certificate. It is theoretically possible to use air flaps in to regulate the amount of air of each one of the nozzles 16 so that uniform drying is obtained. In a hood according to the invention of normal size, however, there are thousands of injection nozzles, so that individual regulation of these would be very difficult to carry out. At a transition A readjustment may also prove necessary from one type of paper to another.

The change in the intensity of drying can be related to the cross section of the material web which can serve as the baseline of a dry content diagram. As a rule, evenly distributed nozzles 16 dried the edges of the web most vigorously. It can also cause overdrying of parts inside the lane. Such a diagram can be made with the help of Set up moisture measurements on the dried paper relatively easily. Based on the diagram the setting of the nozzles can be changed in order to obtain even drying.

Figures 9 and 10 show a simple and effective arrangement for the purpose of such regulation. A bar 28 with folded side edges 29 is inserted into a pressure channel 14, from which the face plate 22 is removed. The folded side edges 29 fit into one of the Nozzles 16 arranged, outwardly curved edge 30, so that you can the bar over a larger or smaller Number of nozzles 16, possibly also over all nozzles of a channel 14.

For this purpose the nozzles 16 are preferably arranged in a row. In the example shown in FIG. 9, the bar 28 covers the nozzles 16 α to 16 /. The parts of the bar 28 which are located in front of the relevant nozzles 16 α to 16 / are denoted by 31a to 31 /. In part 31 α the bar is tight. Part has a small opening 31 b, while in the following parts 31c-31 / the size of the openings grows. This arrangement can reduce the amount of hot air at the edge of the cylinder. Instead of strips with an opening in front of the nozzle one can use _r perforated strips, in which the entire perforated surface with respect to its length unit is variable. The variation of the holes and the size of the perforation along the bar is adapted to the amount of hot air that causes uniform drying. In the case of different types of paper, which may require different settings, different sets of strips with different types of perforation, belonging to each type of paper, can be used. The arrangement can also be used in connection with other injection devices, e.g. B. slots can be used.

A particular advantage of the hood according to the invention is its easy accessibility for cleaning and rearrangement of the injection openings. The suction channels are laid by removing the cover plates 23 17 free so that you can easily get to their floor for cleaning. At the flow openings 19 secretions of particles are formed, which the air flow from the material web carries away. These secretions can be conveniently accessed due to their easy accessibility, e.g. B. with a suitably designed vacuum cleaner nozzle.

After removing the cover plates 23, one can also access the inner surfaces by removing the end plates 22 of the pressure channels 14 come conveniently.

Movable or permanent platforms can be used for such control, cleaning and adjustment work to be ordered. Since the length of the hood is not greater than that of the cylinder, such Set up scaffolding directly at the front of the machine.

In the embodiment shown in the drawing, the partition wall 9 and the walls of the Channels 14 and 17 shown without isolation. With small differences between the temperature of the hot air and that of the humid air, thermal insulation of these walls is not necessary. A warming of the Moist air through the hot air as a result of heat transfer through the partition walls must in general do not mean any major heat loss. In the case of greater temperature differences between hot and moist air, however, it is advisable to cover the aforementioned partition walls with thermal insulation Mistake.

Claims (6)

Claims: 1S 1. Device for drying a web of material, in particular a paper web, which is continuously moved on resting against the jacket of a rotating cylinder, consisting of a hood that partially surrounds the cylinder and encloses a cavity which is positioned against the cylinder by a substantially concentric to the cylinder jacket and to this inner surface arranged at a small distance is delimited, which mainly consists of the perforated floors of side by side in alternating sequence in the axial direction of the cylinder, for blowing hot air against the material web or for its subsequent suction, the length of which is the same that of the cylinder, characterized in that the cavity (10, 11) enclosed by the hood (3) is divided into two chambers of approximately equal size by a partition (9) perpendicular to the axis of the rotating cylinder (2) one (11) as a pressure chamber for the hot air and the other (10) as suction Chamber for the air to be extracted and which are alternately connected to the channels (14 or 17) for blowing in or sucking out the air and are delimited in the axial direction by one end face (7, 8) each, which is connected to the corresponding end face of the cylinder (2) lie essentially in one plane. 2. Apparatus according to claim 1, characterized in that the against the cavity entirely closed pressure channels (14) in the suction chamber (10) and the also closed suction channels (17) are arranged in the pressure chamber (11), which is inside the corresponding chamber alternate with channels opposite to these open channels, the closed channels the one chamber through openings (15, 21) in the partition (9) with the open channels of the other chamber in communication. 3. Device according to claims 1 and 2, characterized in that the hood (3) is provided on the radially inwardly directed ends of the end faces (7, 8) with annular sector-shaped cover plates (23) which are attached to the end faces by means of screws (23 α) or the like. Attached and thus easily removable. 4. Apparatus according to claim 3, characterized in that the radially inwardly directed Part (23 ') of the cover plates (23) made of a soft material, for example felt or the like can rest against the outer edge of the cylinder (2) so that the space between the Hood (3) and the cylinder jacket by bending the soft fabric plates (23 ') without removal the cover plates (23) is accessible. 5. Device according to one of claims 1 to 4, characterized in that the hood (3) is radially oriented and parallel to the cylinder axis arranged separating surfaces (24) is divided, the separating surfaces within the suction channels (17) and, if applicable, the control openings in the outer jacket surface (4) of the hood (26, 27) are arranged. 6. Device according to one of claims 1 to 5, characterized by elongated ones which can be pushed into the pressure channels (14) in their longitudinal direction unevenly perforated plates (28), which with the perforations (16) in the floors the pressure channels cooperate in such a way that they regulate the amount of hot air blown in along the channels to achieve a even drying can be throttled or covered. Considered publications:
U.S. Patent No. 2,218,282. 1 sheet of drawings © »09 528/281 5.58