WO1996026317A1

WO1996026317A1 - Cleaning device

Info

Publication number: WO1996026317A1
Application number: PCT/EP1996/000691
Authority: WO
Inventors: Wolfgang Schneider; Hans-Peter Sollinger; Karlheinz Straub; Jürgen BANNING
Original assignee: Voith Sulzer Papiermaschinen Gmbh
Priority date: 1995-02-24
Filing date: 1996-02-20
Publication date: 1996-08-29
Also published as: EP0817884A1; EP0817884B1; FI111742B; FI973436A; DE59608227D1; DE19507938A1; CN1176674A; DE59603626D1; FI973436A0; DE19507938C2; JPH11502266A; CA2213100A1; ATE186582T1

Abstract

The invention pertains to a device for cleaning a circulating conveyor belt in a paper machine, for example a wet or dry screen belt or a felt band, with at least one nozzle that can be directed towards the fabric belt to apply air or liquid to the fabric belt. The device is designed with a suction chamber (18) that cooperates with the nozzle (8) and is situated so that the spray of dirt loosened from the conveyor belt (4) by the jet (12) and/or water spray or residual water can be sucked into and discharged from the suction chamber (18).

Description

description

Cleaning device

The invention relates to a device for cleaning a conveyor belt in a

Paper-making machine, for example an endless circulating dry or wet screen or a felt, with at least one nozzle which can be directed against the conveyor belt, in particular can be moved in the direction transverse to the conveyor belt, for loading the conveyor belt with air or liquid.

Numerous conveyor belts, in particular fabric belts, are used in paper machines. These conveyor belts become contaminated during the operation of the paper machine; Meshes or pores of these tapes are added, for example, from paper fibers, adhesives or other additives. In order to ensure proper functioning of the conveyor belt, in particular in the dryer section of the paper machine, the conveyor belt must be cleaned.

A cleaning device of the type mentioned at the outset which can be used for this purpose is known from G 92 08 909.7 U1. In this publication, the idea was already given to additionally arrange rotatable spray nozzles which can be moved transversely to the direction of travel of the conveyor belt, so that the nozzle jet not only describes a linear path due to the movability transversely to the direction of travel of the conveyor belt, but also that this linear movement has a circular motion Movement is superimposed. The advantage of such a cleaning device is that liquid sprayed onto the conveyor belt to be cleaned can be applied more uniformly and onto a larger flat area of the conveyor belt. In other words: the rotatable nozzle acts on a relatively wide strip-shaped area of the conveyor belt instead of a linear one. It is therefore better possible to ensure a uniform cleaning of the entire surface of the rotating conveyor belt.

In the known cleaning device, the conveyor belt is acted upon by deflection liquid after deflection by 180 'from above and from the side opposite the transport side. The rotatable nozzles are thus arranged within a loop guide of the endless conveyor belt. Below the conveyor belt, collecting troughs are provided for receiving and removing cleaning fluid and detached contaminants. With this device, however, splash water or dirty water is formed as a result of the liquid jet emerging from the rotating spray nozzle at high pressure and impinging on the conveyor belt. It also proves to be disadvantageous that water remains in the fabric of the conveyor belt, which leads to the moistening of the paper web that comes into contact with the rotating conveyor belt a little later. This can lead to disruptions in the production process, especially with paper webs with basis weights of less than 50 g / m.

Although it has already been proposed to arrange a cleaning device with liquid nozzles, a blow-out device in which the liquid in the fabric band is blown out by means of compressed air. However, this solution suffers from the disadvantage that it or water mist formation occurs, which in turn leads to the moistening of the paper web or the paper machine. A known steam-blowing device with a suction device connected on the same side of the fabric belt also does not produce satisfactory results (DE 43 22 565 AI).

The invention is therefore based on the object of improving a cleaning device of the type mentioned at the outset in such a way that the disadvantages mentioned do not occur, that the device can be produced compactly and in particular in an economical manner and can be used reliably.

This object is achieved according to the invention in that a suction chamber directly surrounding the nozzle is provided, so that dirt and / or water mist or residual water detached from the conveyor belt by the nozzle jet can be sucked in and removed in the shortest possible way into the suction chamber.

In a preferred cleaning device, the suction space is formed by a suction bell surrounding the nozzle in the form of a jacket. In this way, a compact and integral design of a combined nozzle and suction device is achieved. The suction bell can preferably be formed by an essentially cylindrical sheathing of the nozzle which, as is known per se, traverses across the conveyor belt. Instead of a circular cross-section, an elliptical or oval shape can also be provided. The nozzle or the nozzle head can be arranged eccentrically to the sheathing in the opposite direction of the belt.

In a preferred embodiment of the invention, the suction bell is on its side facing the conveyor belt End region is in particular designed to widen bell-shaped or conical. As a result, the flat area of the conveyor belt, which is picked up by the suction bell or by the suction space, is enlarged.

It has proven to be particularly advantageous if the nozzle is inclined with respect to the surface normal of the conveyor belt. For example, one can provide several nozzles inclined in different directions; these cannot be arranged rotating in the traversing suction bell. However, at least one rotating and inclined nozzle is preferably provided, since this enables the nozzle jet to better remove the dirt adhering to the conveyor belt. Because of the nozzle rotation, a cleaning impulse impinging on the conveyor belt from different directions is available. It has been shown that the cleaning effect is most effective in the area of rotation in which the nozzle or the nozzle jet has a speed component which is opposite to the running direction of the conveyor belt. It is therefore proposed to deactivate the nozzle stro technically in the other section, in that the rotatable nozzle jet has a speed component directed in the running direction of the conveyor belt. For this purpose, an aperture can be provided which prevents the nozzle jet from striking. However, with regard to economical water consumption, nozzle feeds which can be acted upon in sections can also be provided. At this point, it should also be pointed out that instead of a rotatable nozzle, a rotatable nozzle head with several nozzles can be provided, one or more of which can be designed as driving nozzles for rotating the nozzle head. It is also possible to provide at least one additional nozzle, the outflow direction of which Conveyor belt runs away, which is used only for the rotary drive.

In order to generate a negative pressure in the suction chamber, it is proposed in a further embodiment of the invention to provide a compressed air injector that can be technically connected to the suction chamber stro.

With regard to a suction effect that is as effective as possible, it has proven to be particularly advantageous if the opening of the suction bell facing the conveyor belt is designed to be adapted to the surface of the conveyor belt or the cylindrical shape of a roller over which the conveyor belt is guided.

The best results were achieved with a cleaning device which can generate water pressures of 100 bar - 1000 bar. In order to keep the liquid consumption as low as possible, liquid nozzles with a nozzle diameter of less than 0.3 mm were used. Diamond, ruby or ceramic materials were used as the nozzle material.

Further features, details and advantages of the invention emerge from the attached drawing and from the following description of various advantageous embodiments of the cleaning device according to the invention. The drawing shows:

Figure 1 shows an embodiment of the cleaning device according to the invention;

FIG. 2 shows a section through a nozzle head that can be used in the device according to FIG. 1; Figure 3 is a view of the nozzle head of Figure 2 from below.

FIG. 4 shows a partial section of the cleaning device according to the invention in accordance with a further exemplary embodiment;

FIG. 5 shows a top view of the cleaning device according to FIG. 4;

6 shows a section through a cleaning device according to a further exemplary embodiment, and

FIG. 7 shows a schematic representation of a dryer section with the cleaning devices according to the invention.

FIG. 1 shows an embodiment of the cleaning device 2, which is arranged for cleaning a dryer fabric belt 4 in the region of a roller 6 of a paper machine, not shown. The cleaning device 2 comprises a rotary nozzle 8 with a rotatable nozzle head 10, which has a nozzle arrangement, not shown. This nozzle arrangement can comprise one or more tangentially flowing driving nozzles for generating a rotational movement in the range of 2000-3000 revolutions per minute as well as one or more cleaning nozzles which serve to act on the dryer fabric 4.

Furthermore, a cylindrical suction bell 14 is provided, which surrounds the nozzle 8 and the nozzle head 10. The interior of the suction cup 14 is connected in terms of flow to a suction line 16 and forms a suction space 18 assigned to the nozzle. or water mist formation occurs, which in turn leads to the moistening of the paper web or the paper machine. A known steam-blowing device with a suction device connected on the same side of the fabric belt also does not produce satisfactory results (DE 43 22 565 AI).

In the case of a preferred cleaning device, the suction space is formed by a suction bell surrounding the nozzle in an antelike manner. In this way, a compact and integral design of a combined nozzle and suction device is achieved. The suction bell can preferably be formed by an essentially cylindrical sheathing of the nozzle which, as is known per se, traverses across the conveyor belt. Instead of a casing with a circular cross section, an elliptical or oval shape can also be provided. The nozzle or the nozzle head can be arranged eccentrically to the sheathing in the opposite direction of the belt.

In a preferred embodiment of the invention, the suction bell is on its side facing the conveyor belt Dryer screen 4 and so removes the contaminants from its surface. Due to the superimposition of the traversing movement and the rotational movement of the cleaning nozzle, the dirt particles are hit by the liquid jet of the cleaning nozzle in different directions and can therefore be detached more easily than when a nozzle running parallel to the longitudinal axis direction 26 is used. The inclination of the cleaning nozzle or the liquid jet also has the effect that the impinging liquid jet is reflected in the suction space 18 and the water mist which is formed, with dirt particles bound therein, and residual water can be discharged via the suction line 16. There is a suction effect or flow represented by the arrows. No splash water therefore occurs around the suction bell 14, so that dirt or water leakage can be largely avoided. It has proven to be particularly advantageous if the negative pressure in the suction chamber 18 and the suction line 16 is generated by means of a compressed air injector. Furthermore, it has proven to be advantageous if the negative pressure in the suction space 18 can be changed and thus can be adapted to different operating conditions.

FIGS. 2 and 3 show a nozzle head 10 'corresponding to the rotatable nozzle head 10 in different views. The nozzle head 10 'is rotatably held on a flange 30 by means of a bearing 28. Provided in the interior of the flange 30 is a stationary nozzle feed line 32, which flows into a pressure chamber 34, the walls 36 of which bear sealingly against the inside of a cylindrical component 38. The cylindrical component 38 has four openings arranged at an angle of 90 'to one another. Connected to this are nozzle feed lines 40, which extend radially outward and in their end section for preferred are bent 90 °, as can be clearly seen in FIG. The nozzle feed lines 40 finally end in inclined cleaning nozzle end regions 42. The driving nozzles also provided are not shown. As can also be seen from FIGS. 2 and 3, only one of the nozzle feed lines 40 is always pressurized, while the other nozzle feed lines 40 are depressurized. The pressure chamber 34 is now oriented in such a way that the liquid jet has a speed component opposite the direction of travel of the dryer fabric 4, so that the cleaning effect is particularly high. Thus, however, the nozzles, the liquid jet of which would have a speed component in the running direction of the dryer fabric 4, are depressurized with regard to a low water consumption and are therefore deactivated.

The cleaning nozzles are designed for a pressure range from 150 bar to 300 bar and have a nozzle diameter of 0.3 mm. Sapphire or ceramic materials are preferably used as the nozzle material.

A second exemplary embodiment of a cleaning device is shown schematically in FIGS. 4 and 5. This corresponds essentially to the cleaning device described with reference to FIGS. 1 to 3, which is why a repeated explanation of the corresponding parts is dispensed with. One difference is the oval cross-sectional shape of the suction bell 14, in which the nozzle head 10 is arranged eccentrically in the opposite direction of the belt running (arrow P). This improves the suction effect on the water mist (loaded with dirt).

Another difference of this cleaning device compared to that shown in Figure 2 is that no pressure chamber 34 is provided. The water supply line 32 is connected to all four nozzle feed lines 40 shown in FIG. Thus, all four nozzle feed lines 40 are pressurized.

A screen 61 is provided between the nozzle head 10 and the dryer fabric belt 4, the outermost edge 63 of which is angled. This edge 63 serves as a fastening edge for webs 65, which in turn are connected to the inner wall of the suction bell 14. Openings or gaps 67 are formed between the individual webs 65, the suction cup wall 14 and the panel edge 63, via which a connection from the suction chamber 18 to the outside is created.

The aperture 61 has an opening 69, which is located in the effective area of the rotating cleaning nozzles 71. The dimensioning and position of this opening 69, in particular in the circumferential direction of the diaphragm 61, is selected such that at least one cleaning nozzle 71 always passes through this area, the direction of the nozzle jet being opposite to the direction of tape travel (arrow P).

Thus, in accordance with the previously described function of the pressure chamber 34, it is achieved in any case that only one cleaning nozzle 71 acts on the dryer fabric belt 4. The three further cleaning nozzles shown in FIG. 5 also work, but the liquid jet does not impinge on the dryer fabric belt 4 but on the screen 61. This liquid is sucked into the suction chamber 18, as indicated by the arrows shown in FIG the edge 63 of the screen 61 also has a deflecting function.

The liquid mist reflected by the dryer fabric belt 4 is sucked into the suction chamber 18 either through the aperture 69 or through the aforementioned gap 67. As in the first exemplary embodiment, the rotor head 10 is driven via nozzles 73. It can be seen from FIG. 4 that these nozzles 73 are oriented in such a way that the escaping medium has an axial flow component which is opposite to the axial component of the liquid jet . This makes it possible to compensate for the axial recoil forces, which leads to a relief of the bearing 28.

However, the cleaning process itself corresponds to that described in connection with FIGS. 1 to 3. Therefore, we shall not go into this further at this point.

FIG. 6 shows a further exemplary embodiment of a cleaning device according to the invention, in which, however, no rotating cleaning nozzles are provided. Rather, the cleaning nozzles 81 are firmly connected to the suction bell 14. The cleaning nozzles 81 are oriented toward the center of the suction cup 14 in such a way that the liquid jets 83 preferably meet at a point which lies opposite the opening area of the suction cup 14. If this point lies directly on the conveyor belt, a point-wise loading is achieved. If the distance between the nozzles and the conveyor belt is changed, the intersection of the liquid jets also shifts. The punctiform application then becomes a flat application.

The liquid mist bouncing off the dryer fabric belt 4 is sucked into the suction chamber 18, as in the previous cases. The suction effect is intensified by the suction bell which continues below the nozzles 81 and which ends very close to the conveyor belt. By formed between the suction bell 14 and the conveyor belt 4 In this case, air flows through gap 85, which sweeps the liquid mist with it.

As explained in the exemplary embodiments described above, the cleaning nozzles 81 are aligned such that the component directed in the direction of movement of the dryer fabric belt 4 is as small as possible.

Although only three cleaning nozzles 81 are shown in FIG. 6, more than three such cleaning nozzles can also be provided.

A section of a drying section is shown schematically in FIG. 7, two single-row drying groups 91 and 93 being indicated. Each of these two drying groups 91 and 93 is composed in a known manner from a plurality of drying cylinders 95 and deflection rollers 97. Drying cylinders 95 and deflecting rollers 97 are arranged in such a way that the paper web alternately passes through drying cylinders and deflecting rollers and the dryer group passes through in a meandering fashion.

Each dryer group 91 and 93 is assigned a dryer fabric belt 4, which runs onto the paper web at the beginning of each dryer group and is removed and returned at the end of the dryer group.

It can be seen from FIG. 7 that a cleaning device 2 interacts with a dryer fabric belt 4. The two cleaning devices 2 are each arranged on a dryer fabric guide roller 6 in the initial region of the return of the dryer fabric belt 4. It can thus be achieved that the cleaning liquid remaining on the dryer fabric belt 4 can evaporate before the dryer fabric belt comes into contact with the paper web again. The guide rollers of the return following the roller 6 also help to remove liquid from the Dryer screen belt 4 at, on the one hand due to the overpressure arising in each “run-up gusset” and on the other hand due to the centrifugal force exerted on the liquid particles during the run around the roller.

Claims

claims

1. Device for cleaning a conveyor belt in a paper making machine, for example a dry or wet sieve belt or a felt belt, with at least one nozzle directed against the conveyor belt for loading this conveyor belt with air or liquid, characterized in that a nozzle ( 8) interacting suction chamber (18) is provided, of which the nozzle (8) is assigned in such a way that dirt and / or water mist or residual water detached from the conveyor belt (4) through the nozzle jet (12) into the Suction chamber (18) can be sucked in and discharged.

2. Device according to claim 1, characterized in that the suction chamber (18) is formed by a suction bell (14) surrounding the nozzle (8) in the form of a jacket.

3. Device according to claim 1 or 2, characterized gekenn¬ characterized in that the suction bell (14) has a rubber jacket or brushing.

4. Device according to one of the preceding claims, characterized in that the end region (22) of the suction bell (14) forming the opening on the conveyor belt side of the suction bell (14) is adapted to the surface profile of the conveyor belt (4) or the cylindrical shape of a roller (6) is.

5. Device according to one of the preceding claims, characterized in that the conveyor belt-side end region (22) of the suction bell (14) is designed to widen in the direction of the conveyor belt (4).

6. Device according to one of the preceding claims, characterized in that the conveyor belt side End region (22) of the suction cup (14) projects beyond the nozzle (8) in the direction of the conveyor belt (4).

7. Device according to one of the preceding claims, characterized in that the nozzle is rotatable about an axis.

8. The device according to claim 7, characterized in that the rotatable nozzle (8) is inclined against the axis of rotation (26).

9. Device according to one of the preceding claims, characterized in that in a section in which the nozzle jet of the nozzle (8) in the direction of travel of the conveyor belt (4) pointing velocity component, the nozzle (8) is fluidically inactive.

10. The device according to claim 8, characterized in that an aperture is provided for shielding the nozzle (8) in the section with the speed component of the nozzle jet directed in the running direction of the conveyor belt (4).

11. The device according to claim 8, characterized by nozzle sections (40) which can be acted upon in sections.

12. Device according to one of the preceding claims, characterized by a rotatable nozzle head (10) having a plurality of nozzles.

13. The apparatus according to claim 1, characterized by an oval or elliptical cross section of the suction chamber (18).

14. The apparatus according to claim 13, characterized in that the suction chamber cross-section in the tape running direction (Arrow P) extends, and that the nozzle or the nozzle head (10) is arranged eccentrically in the suction space (18) against the direction of travel of the belt.