WO2013128062A1

WO2013128062A1 - Apparatus and method for cleaning a roll in a fiber web machine and element

Info

Publication number: WO2013128062A1
Application number: PCT/FI2012/051108
Authority: WO
Inventors: John Fagerlund; Sami Makkonen
Original assignee: Metso Paper, Inc.
Priority date: 2012-02-28
Filing date: 2012-11-14
Publication date: 2013-09-06
Also published as: CN204353130U; EP2819790A4; DE202012013309U1; EP2819790A1; AT15077U1; FI20125223L

Abstract

The invention relates to an apparatus for cleaning a roll in a fiber web machine. The apparatus includes a cleaning head (10) and an element (11) made of a porous material adapted thereto. The element (11) made of a porous material is adapted to be set in contact with the surface (13) of a roll (12). The apparatus also includes means (14) for creating a vacuum effect on the cleaning head (10) and further on the surface (13) of the roll (12). The cleaning head includes nozzle elements (19) for supplying fluid to the surface (13) of the roll (12). In addition, the element (11) made of a porous material is arranged around the nozzle elements (19). The invention also relates to a method for cleaning a roll in a fiber web machine and an element.

Description

APPARATUS AND METHOD FOR CLEANING A ROLL IN A FIBER WEB MACHINE AND ELEMENT

The invention relates to an apparatus for cleaning a roll in a fiber web machine, the apparatus including

a cleaning head,

an element made of a porous material adapted to the cleaning head and arranged to be set in contact with the roll surface, and

- means for creating a vacuum effect on the cleaning head and further on the roll surface.

The invention also relates to a method for cleaning a roll in a fiber web machine and an element. Canadian patent application No. 2493324 proposes an apparatus for cleaning a heatable roll surface. The apparatus includes a cleaning head which is adapted against the roll surface. The cleaning head is provided with a flexible cushion which forms the element made of a porous material. When loading the cleaning head, the cushion is compressed. In addition, a vacuum effect is created on the cleaning head and the roll rotates during cleaning.

The cleaning head extending over the entire roll length is only suitable in certain positions and certain rolls. Moreover, the cleaning effect of the cushion is modest. On the other hand, the cushion may damage the roll surface. A sizeable cleaning head requires large equipment for creating a vacuum effect. Nevertheless, the vacuum effect is small. The cleaning head itself is also a massive construction. The compression of the cushion may prevent the vacuum effect from extending to the roll surface, which further diminishes the efficiency of the apparatus. A sizeable cushion is expensive and difficult to replace. In addition, the cleaning effect may vary locally and the entire cushion must be replaced when a part of it gets soiled. The object of the invention is to provide a novel apparatus for cleaning a roll in a fiber web machine, the cleaning effect of said apparatus being better than before and the lifetime longer than earlier. Another object of the invention is to provide a novel method for cleaning a roll in a fiber web machine, the method being applicable in context with different rolls and enabling the determination of the current cleaning effect. The characteristic features of the apparatus according to this invention are that the cleaning head includes nozzle elements for supplying fluid to the roll surface and that the element made of a porous material is arranged around the nozzle elements. Correspondingly, the characteristic features of the method according to the element are that fluid is supplied to the roll surface, the supply point of said fluid being surrounded with an element made of a porous material. The characteristic features of the element according to the invention are set forth in claim 13. A good cleaning efficiency is achieved with the novel construction. Despite the use of fluid, the roll surface can be immediately used for production when the nozzle elements are surrounded by the element made of a porous material . The apparatus is also provided with other functionalities which make the apparatus versatile and reliable in operation. Furthermore, the method can be used to monitor the operation and performance of the element. In addition, the element is fast to replace in the apparatus.

The invention is described below in detail by making reference to the enclosed drawings which illustrate some of the embodiments of the invention, in which

Figure 1 shows a cleaning head according to the invention adapted against a roll surface,

Figure 2 is a bottom oblique view of a cleaning head according to the invention,

Figure 3a is a bottom view of a cleaning head according to the invention, Figure 3b shows the operating means of cleaning head according to the invention,

Figure 4a is a right hand side view of cleaning head according to the invention,

Figure 4b is a left hand side view of cleaning head according to the invention,

Figure 5a is a front view showing the basic diagram of the operating means of a cleaning head according to the invention,

Figure 5b is a lateral view of one position of the operating means according to the invention,

Figure 5c shows a second position of the operating means of

Figure 5b,

Figure 5d is a front oblique view of an element according to the invention.

One of the rolls requiring cleaning is the counter roll of the coating station of a fiber web machine. For example, coating paste remains in the counter roll due to the holes in the web to be coated, which is why the roll has to be cleaned at intervals. Cleaning is a requirement for the faultless operation of the coating process and to guarantee the quality of the end product. Other rolls located in different positions must also be cleaned. A fiber web machine refers to paper, board, tissue and pulp drying machines and their finishing equipment, such as coating equipment and/or a calender.

Figure 1 illustrates the cleaning head 10 of an apparatus according to the invention. The cleaning head is supported to the frame of the fiber web machine with guides and is traversed in the cross direction of the fiber web machine in accordance with the cleaning need. Traversing is depicted with a double-headed arrow in Figure 1. The apparatus is thus meant for cleaning a roll in a fiber web machine. The apparatus includes a cleaning head 10 and an element 11 made of a porous material adapted thereto. The element 11 made of a porous material is adapted to be set in contact with the surface 13 of a roll 12 as shown in Figure 1. The roll rotates during the roll cleaning. In addition, the apparatus includes means 14 for creating a vacuum effect on the cleaning head 10 and further on the surface 13 of the roll 12. The vacuum effect generates aspiration which removes the material detached from the roll surface. The cleaning head includes a cleaning shoe 15 which is formed into a curved shape. The vacuum effect is conveyed to a suction chamber 16 created within the cleaning shoe, via a suction pipe 17. The suction pipe has a flexible suction hose 18 connected thereto (Figure 3b) . The suction hose extends to a vacuum aggregate provided with a separator for separating material from the air flow. According to the invention, the cleaning head includes nozzle elements 19 for supplying fluid to the surface 13 of the roll 12. In addition, an element 11 made of a porous material is arranged around the nozzle elements 19. Firstly, high-pressure fluid, such as water, efficiently detaches material from the roll surface. A ring-like element made of a porous material arranged as a preferably essentially closed circumference, prevents the spread of fluid outside the cleaning shoe. In addition, a contacting element made of a porous material detaches material. In addition, the element made of a porous material absorbs the fluid thus avoiding that a moisture streak remains on the roll surface. The porosity of the element also enables an air flow through the element. This air flow generating in the cleaning head removes the material detached and the fluid supplied from the roll surface and further from the cleaning head.

The nozzle elements 19 are adapted to a nozzle body 20. In Figure 1, the nozzle body 20 is extended by quick connecting means 21 to which a high-pressure hose is connected 22 (Figure 3b) . The nozzle elements 19 are thus adapted to the common nozzle body 20 which is additionally quick-disconnectably connected to the cleaning head 10. Thus the nozzle body including the nozzles is fast to replace, which enables very short maintenance times. The nozzle body removed can then be serviced or repaired without haste.

Figure 2 is a bottom oblique view of the cleaning head 10. The element 11 made of a porous material is a continuous sheet made of a porous material with an opening 23 arranged therein for the nozzle elements 19. The element made of a porous material forms a continuous circumference, which avoids generation of leak flows. At the same time, since the air flow through the element made of a porous material is substantially equal in different positions, the vacuum effect is uniformly distributed and moisture streaks can be avoided.

Preferably, the porous material is a compressible abrasive sponge. Firstly, the compressibility guarantees a good contact with the roll surface and cleaning is not hindered by possible roll vibrations. Secondly, the cleaning efficiency of an abrasive sponge is good as such. The material and roughness of the abrasive sponge are selected in accordance with the roll surface to avoid surface damage. The porosity of the abrasive sponge is of great significance for the generation of suction and it also influences the water retention capacity of the abrasive sponge. Generally, the rougher the abrasive sponge, the more porous it is. In addition, any hard impurities will dig into the pores of the abrasive sponge preventing damage to the roll surface. Figure 3a is a bottom view of the cleaning head 10. The nozzle elements 19, installed in a slightly inclined position, are located first in the rotating direction of the roll. Thus the water jet hits the roll surface in an inclined position guiding the detaching material towards the suction pipe. An inclined shower effectively removes material and affords the material detached a movement in the direction of the air flow. For example, an element made of a porous material can be glued to the bottom surface of a cleaning shoe. However, the element is a wearing part and should therefore be replaced at intervals. Detaching the glued element is difficult and 5 reguires the use of tools, which, however, can be avoided by utilizing a sticker. Preferably, the element 11 made of a porous material is attached to a support structure 24 which is quick-disconnectably connected to the cleaning head 10. In Figures 4a and 4b, the support structure 24 is a support plate

10 25 which is formed in accordance with the cleaning shoe 15. The support plate is also provided with an opening and the element made of a porous material can be connected to the support plate by gluing, for example. Here the ends of the support plate 25 are bent as protrusions 26 and 27. The screw heads of two

15 screws 28 located in the rear part of the cleaning shoe 15 extend through the protrusion 26. For this, the protrusion 26 has two holes that are slightly larger than the screw heads (Figure 5d) . Correspondingly, a push button 29 located in the front part of the cleaning shoe 15 extends through the other

20 protrusion 27. For this, the other protrusion 27 has a hole that is slightly larger than the push button 29. The push button is pushed to detach the support plate, which enables the support plate to be turned downwards and then pushed backwards whereupon the support plate detaches from the screws. A new

25 abrasive sponge with its support plate is installed in the reversed order. First, the rear-most protrusion of the support plate is set on the screws and the support plate is turned against the cleaning shoe. Due to the effect of the other protrusion, the push button is pressed in and rises up at the

30 hole whereupon the support plate locks in place. Figures 4a and 4b also depict a quick-locking latch 30 whose unlocking detaches the nozzle body 20 from the cleaning shoe 15.

With an element made of a porous material, impurities can be 35 controllably detached from the roll surface and kept within the suction chamber. Furthermore, with an element made of a porous material, the cleaning head does not leave a moisture streak. The cleaning head has a simple design and the element made of a porous material can be easily replaced in the cleaning head. Figure 3b illustrates the support method of the cleaning head 10 in more detail. Here the apparatus includes operating means 31 for loading the element 11 against the roll surface. In addition, said operating means 31 include a mechanism 32 which is adapted to retain the angular position of the cleaning head 10 regardless of the state of the operating means 31. The operating means 31 are composed of a vertical beam 33, connectable to guides, and a bottom beam 34 articulated thereto. A pneumatic cylinder 35 enabling the mutual position of the beams 33 and 34 to be changed is arranged between the beams 33 and 34. The bottom beam 34 has a cleaning head 10 connected thereto which can thus be loaded against the roll surface and, on the other hand, raised off the roll surface. Due to the mechanism, the alignment of the cleaning head relative to the roll surface remains constant. Preferably, the beams 33 and 34 are box-like constructions, shown in Figure 3b without side plates.

The mechanism is simple and here it is composed of a lever mechanism arranged within the bottom beam. The lever mechanism is fully protected within the closed bottom beam. Figures 5a-c illustrate the principle of the design and operation of the lever mechanism. A shaft 36, to which the cleaning head 10 is ' rigidly connected, is adapted through the bottom beam 34. A crank arm 37, which is rigidly connected to the shaft 36, is located within the bottom beam 34. Correspondingly, another crank arm 39 is rigidly connected to a joint pin 38 of the bottom beam 34. The crank arms 37 and 39 are connected to each other with a connecting rod 40. Thus, as the bottom beam 34 turns relative to the joint pin 38, the shaft 36 always remains in the same alignment, which is illustrated with an arrow in Figures 5b and 5c. Then the cleaning head always remains at the desired angle relative to the roll. In addition, an adjustment system between the shaft 36 and its crank arm 37 can be used for the fine adjustment of the mutual position between these. The adjustment system is mainly needed during the startup of the apparatus only and when the configuration or the operating environment of the apparatus changes for some reason.

The invention also relates to a method for cleaning a roll in a fiber web machine. In the method, an apparatus is used which includes a cleaning head 10 equipped with an element 11 made of a porous material said cleaning head being set in contact with the surface 13 of a roll 12. In addition, a vacuum effect is created on the cleaning head 10 to remove the material detached from the cleaning head. According to the invention, fluid is supplied to the surface 13 of the roll 12, the supply position of said fluid being surrounded with the element 11 made of a porous material. This improves cleaning and avoids the spread of the fluid to the environment as well as generation of moisture streaks. The cleaning head provides an efficient cleaning effect on a small area at a time. Hence the cleaning head is moved on the roll surface in the cross direction of the fiber web machine enabling the roll to be cleaned over its entire width. The apparatus can be controlled manually or according to a programmed sequence. The control can also be based on a local cleaning need of the surface.

Surprisingly, the extent of the vacuum effect is measured and, based on the measurement result, the cleaning head is adjusted to load by an adapted force. Thus the element made of a porous material can be optimally compressed without blocking or excessively hindering the air flow. The measurement obtained can be utilized in another way, too. In the invention, based on the measurement result, an indication is formed of the condition of the element made of a porous material. In practice, while the measurement result remains substantially equal during the operation, the measurement result changes as the element made of a porous material gets soiled, for example. When the element made of a porous material gets soiled, its pores become filled with material, which then blocks or at least hinders the air flow. Then the pressure in the suction chamber changes, which can be regarded as an indication of a replacement need of the element made of a porous material. In practice, the vacuum measurement arranged in the suction channel of the cleaning shoe is used to optimally adjust the pressure of the cleaning head against the surface and monitor the retention of porosity of the abrasive sponge.

In the embodiment of Figure 3b, a connecting hose 41, adapted to a vacuum transmitter 42 located further away from the cleaning head, is installed in the suction hose 18. A current output comparable to the pressure, obtained from the vacuum transmitter 42 is connected to a control system 43 which controls the control valves 44 of a pneumatic cylinder 35. In this way, the ring-like element made of a porous material mountable to the bottom of the cleaning shoe with a quick locking system can be made to press with optimal force against the surface of the roll to be cleaned using the operating means. High-pressure cleaning fluid, typically water, sprayed to the surface to be cleaned from the nozzle elements, in combination with the porous abrasive sponge contacting the surface, detaches the impurities from the roll coating. Due to the suction flow, the particles detached and the cleaning fluid end up in the suction pipe. The required suction flow is achieved because the abrasive sponge is porous allowing air to flow therethrough (Figure 4a) . The control system can also be connected to the machine control system of the fiber web machine .

The cleaning head 10 is equipped with nozzle elements 19 and a suction chamber 16 which are adapted to the cleaning head 10. Preferably, the cleaning head 10 has a slightly curved shape on its side lying against the surface 13 of the roll 12, conforming to the surface 13 of the roll 12. The nozzle elements 19 supply the fluid brought to the cleaning head 10 onto the surface 13 of the rotating roll 12. In the embodiment shown, the number of nozzle elements 19 is five and they are fan-type nozzles. The fluid pressure may range, for example, from 75 to 200 bar. The suction chamber 16 creates a vacuum effect or a suction area on the surface 13 of the roll 12 thus aspirating the material detached. Figure 2 illustrates an apparatus equipped with an additional feature. Here the cleaning head 10 further includes a curved sealing blade 45, adapted to be set in contact with the roll surface, which opens to the direction of the nozzle elements 19_* The sealing blade wipes off the fluid already before the element 11 made of a porous material. In other words, the sealing blade improves cleaning and prevents generation of moisture streaks. The sealing blade 45 is adapted into the opening 23, at the trailing edge. In practice, the sealing blade has a lower profile than the element made of a porous material. Thus the sealing blade contacts the roll surface only after the element made of a porous material is at least partially compressed due to the loading effect. The material of the sealing blade may be, for example, polyurethane or a similar suitable material (trade name Vulkollan, for example) and its hardness may range, for example, from ShA 70 to 98, and more specifically from ShA 85 to 95. A small compressibility can be allowed for the sealing blade 18. The use of the sealing blade does not wear or damage the roll surface. Figure 5d shows an element according to the invention for use in an apparatus according to the invention. Here the element 11 made of a porous material is attached to a support structure 24 which is adapted to be connected around the nozzle elements of the cleaning head. More specifically, the support structure 24 is a support plate 25 including protrusions 26 and 27 for quick-disconnectably connecting the support plate 25 to the cleaning head 10. The disconnection and connection of the element are described above. Departing from shown, the element can be wider than the cleaning head. It can also be longer than the cleaning head particularly in the leading edge direction. Then, a cleaning head of one size can be used with elements of different sizes, which makes it possible to adapt the cleaning efficiency of the apparatus to each specific situation. An element 11 slightly wider than the cleaning head 10 is illustrated in Figure 4b. In practice, the difference in width and length can be several tens of millimeters. Then the support plate keeps the element made of a porous material in the correct shape.

Preferably, the element 11 further includes a curved sealing blade, adapted to be set in contact with the roll surface, which opens to the direction of the nozzle elements. Then, when replacing the element, the replacement of the sealing blade is also achieved. The sealing blade 45 is shown in Figure 2, in which the element 11 made of a porous material is glued to the cleaning shoe 15.

D.ue to the novel cleaning head, the apparatus can be used during the normal production run as well as during web breaks. Despite an abrasive sponge, the apparatus is gentle towards the roll surface. The sealing blade can also be used without causing damage to the roll. In addition, the cleaning operation can be fully automated. Service operations are quick to perform, which improves safety at work. The cleaning itself is also quick to perform due to the good cleaning efficiency and low residual moisture, which also reduces the amount of cleaning broke. Furthermore, the maintenance need of the apparatus is low and the wearing parts can be replaced without tools.

Claims

1. Apparatus for cleaning a roll in a fiber web machine, the apparatus including

a cleaning head (10),

an element (11) made of a porous material adapted to the cleaning head (10) and arranged to be set in contact with the surface (13) of a roll (12) , and

means (14) for creating a vacuum effect on the cleaning head (10) and further on the surface (13) of the roll

(12) ,

characterized in that, the cleaning head (10) includes nozzle elements (19) for supplying fluid to the surface (13) of the roll (12), and the element (11) made of a porous material is arranged around the nozzle elements (19) .

2. Apparatus according to claim 1, characterized in that the element (11) made of a porous material is a continuous sheet made of a porous material with an opening (23) arranged therein for the nozzle elements (19) .

3. Apparatus according to claim 2, characterized in that the porous material is a compressible abrasive sponge.

4. Apparatus according to any of claims 1 - 3, characterized in that the element (11) made of a porous material is connected to a support structure (24) which is quick-disconnectably connected to the cleaning head (10) .

5. Apparatus according to any of claims 1 - 4, characterized in that the nozzle elements (19) are adapted to a common nozzle body (20) which is quick-disconnectably connected to the cleaning head (10) .

6. Apparatus according to any of claims 1 - 5, characterized in that the apparatus includes operating means (31) for loading the element (11) against the surface (13) of the roll (12), and said operating means (31) include a mechanism (32) which is adapted to retain the angular alignment of the cleaning head (10) regardless of the state of the operating means (31).

5

^■

7. Apparatus according to any. of claims 1 - 6, characterized in that the cleaning head (10) further includes a curved sealing blade (45), adapted to be set in contact with the surface (13) of the roll (12), opening to the direction of the 10 nozzle elements (19).

8. Apparatus according to claim 7, characterized in that the sealing blade (45) is adapted into an opening (23) at the trailing edge.

15

9. Method for cleaning a roll in a fiber web machine in which method an apparatus is used which includes a cleaning head (10) equipped with an element (11) made of a porous material, said cleaning head being set in contact with a

20 surface (13) of a roll (12), and a vacuum effect is. created on the cleaning head (10) , characterized in that fluid is supplied to. the surface (13) of the roll (12) the supply position of said fluid being surrounded with the element (11) made of a porous material .

25

10. Method according to claim 9, characterized in that the cleaning head (10) is moved on the surface (13) of the roll (12) in the cross direction of the fiber web machine.

30 11. Method according to claim 8 or 9, characterized in that the extent of the vacuum effect is measured and, based on the measurement result, the cleaning head (10) is adjusted to load by an adapted force.

12. Method according to claim 11, characterized in that, based on the measurement result, an indication is generated of the condition of the element (11) made of a porous material.

13. Element for use in the apparatus according to claim 1, characterized in that the element (11) made of a porous material is connected to a support structure (24) which is adapted to be connected to the cleaning head (10) around the nozzle elements (19).

14. Element according to claim 13, characterized in that the support structure (24) is a support plate (25) including protrusions (26, 27) for quick-disconnectably connecting the support plate (25) to the cleaning head (10).

15. Apparatus according to claim 13 or 14, characterized in that the element (11) further includes a curved sealing blade (45) opening to the direction of the nozzle elements (19) which is adapted to be set in contact with the surface (13) of the roll (12) .