WO2007048876A1

WO2007048876A1 - Method and equipment for removing water from felt

Info

Publication number: WO2007048876A1
Application number: PCT/FI2006/050458
Authority: WO
Inventors: Jorma Lindeman
Original assignee: Upm-Kymmene Corporation
Priority date: 2005-10-27
Filing date: 2006-10-24
Publication date: 2007-05-03
Also published as: FI20051086A; CN101331268A; FI20051086A0; EP1954876A4; EP1954876A1

Abstract

the invention is related to a method and equipment for removal of water from a moving felt (1), wherein by using said method at least a part of water is removed from below by exposing the lower surface of the felt (l) to a low pressure. In addition to the low pressure the lower surface of the felt (1) is subjected from below, in front of said location of the low pressure, seen in the running direction of the felt, a surface (9a, 9b) having substantially the same width as the felt.

Description

Method and equipment for removing water from felt

The subject of the invention is a method in accordance with the preamble of claim 1 and an equipment in accordance with the preamble of claim 4 for removing water from moving felt..

The invention can be utilised in connection with endless felts used in paper machines and board machines for removing water during the manufacturing stages of paper and board or similar product.

hi accordance with the prior art techniques water is removed from the felt by using special suction devices arranged below the felt and having a transversal suction box with regard to the direction of the movement of the felt, the width of the said suction box corresponding the width of the felt and further having a group of battens in connection with the top surface of the suction box, said battens being made of ceramic material or some other abrasion resistive material, wherein a gap has been arranged between the battens next to each other to provide the removal of water. Low pressure is arranged inside the suction box in order to arrange the removal of water through the gaps between the battens next to each other. The disadvantage of these prior art solutions has been the fact that in order to arrange the removal of water in a secure and adequate manner the constructions have become rather large in size. Thus the constructions are expensive and due to the large size of the same the pressure directed to the rollers, around which the felt is run, is increased. Additionally, due to the low capacity of water removal the known constructions are a limitation as to the running speed of the felt is concerned.

The object of the present invention is to remove drawbacks of the prior art solutions discussed hereabove and to accomplish a method and an equipment for removing of water from the moving felt, which is advantageous and reliable together with operative security and adequate capacity to the nearest best behaviour. The method of the invention is characterised in accordance with the characteristic part of claim 1. Correspondingly, the equipment of the invention is characterised in accordance with the characteristic part of claim 4. As to the other embodiments of the present invention they are characterised by the features presented in other patent claims. The advantage of the solution in accordance with the invention is the fact that the invention provides the possibility for removing of water by using equipment beneficial both as far as the size i.e. dimensions and economy are concerned. Additionally, the solution in accordance with the invention serves for high running speeds. One further advantage lies in the fact that the abrasion directed to the lower surface of the hood is not too extensive.

The invention s more closely explained in the following description, by means of an embodiment with reference to the accompanying drawings, in which

Fig 1 shows one equipment of the invention in a simplified manner placed below the endless felt and seen from the side elevation view,

Fig. 2 shows the equipment in accordance with the Fig. 1 in a larger scale and further seen from the side elevation view,

Fig. 3 shows one embodiment of the invention seen from the side elevation view, Fig 4 shows yet one another embodiment of the invention seen from he side elevation view,

Fig 5 shows in a larger scale the upper end of the solution of means for removing of water in accordance with one embodiment of the invention seen from the side elevation view and

Fig 6 shows in a larger scale the upper end of the solution of means for removing of water in accordance with another embodiment of the invention seen from the side elevation view.

Fig. 1 shows in a simplified manner how the dewatering equipment 3 of the invention is located below one endless felt 1 in a paper machine or a board machine or alike. Herebelow common nomination "process machine" is used when referred to a paper machine or a board machine or alike. The dewatering equipment 3 is placed in transversal direction with respect to the running direction of the moving felt 1. The running of the felt 1 is directed by means of rollers 2, two of which is seen in the simplified figure, but, however, in an operative process machine can be found usually several in number. The solution of the invention is specially suitable in connection with the press part of the process machine, whereupon felts are arranged for removing of water, but may as well be the case that the same solution is used in connection with the felts for removing of water in the other parts of the process machine. The felt is moving in the direction of the arrow 6 in Fig. 1. The dewatering equipment 3 has a suction box 4 attached to a fixed place in the frame 5 of a paper machine or a board machine or alike. Additionally, according to the invention, in front of the suction box of the suction equipment 3, seen in the running direction 6 of the felt 1, one or several means for removing of water 9 has been arranged.

Fig. 2 shows the suction equipment 3 in accordance with Fig. 1 in a larger scale and in a sectional view. The top surface of the suction box 4 comprises ceramic battens 7, substantially having the same width as the felt 1 and being arranged transversally with respect to the running direction of the felt in a manner that between two battens there is a gap 8, through which water is sucked from the felt 1 into the suction box 4. In front of the suction box 4 seen in the running direction 6 of the felt 1 at least one means for removing water 9, acting like a doctor blade, has been arranged, the head 9a of said means 9 being further arranged from below the felt 1 to press the lower surface of the felt 1 upwards. A discharge chute 10 or alike has been placed below means for removing water 9 from the felt 1 to dissipate scraped water. At least the fixed head 9a of means for removing water 9 pressing the felt 1 is substantially in transversal direction with regard to the running direction of the felt 1 and having substantially the same width as the felt. The head of means for removing water 9 is rounded in a suitable manner leading to the fact that the felt 1 is pressed from below by a curved surface, hi accordance with the solution of Fig. 2 means for removing water 9 are fixed to the front surface of the suction box 4, but the site of attachment can nevertheless be some other suitably chosen one in front of the suction box.

Fig.. 3 shows a solution of one advantageous embodiment of the invention, whereby two means for removing water are placed one after the other in front of the suction box 4 in a manner that the heads 9a of means for removing water are arranged substantially close to each other. A discharge chute 10 is placed underneath both of the heads 9a.

Fig.. 4 shows a solution of one another advantageous embodiment of the invention, whereby a roller 9c is arranged in the transversal direction with regard to the running direction of the felt 1 at the top end of means for removing water 9, in front of the suction box 4, said roller 9c having curved cylindrical surface functioning as the head 9b of means for removing water. The roller can be solid, and having the width of the felt or a combined group of several short rollers. According to this solution the roller 9c of means for removing water 9 is arranged to rotate together with the movement of the felt 1 and press the felt 1 from the lower surface of the same.

Fig. 5 shows in a larger scale the construction of the top end of means for removing water 9, whereby the head 9a has been rounded in a manner that the radius of curvature R is suitably between the limits of 0-20 mm, preferably between the limits of 2-16 mm. The head 9a can be manufactured out of ceramic, metallic or out of some other abrasive resistant material. Additionally, the angle of clearance A of the head 9a against the lower surface of the felt 1 is suitably between the limits of 10-30 degrees, preferably between the limits of 15-20 degrees. The curved head 9a of means for removing water 9 forms a curved surface 9a, placed beneath the felt 1 and having substantially the same width as the felt, pressing the felt from below.

Correspondingly, Fig.. 6 shows in a larger scale the top end construction of means for removing water 9 in accordance with another embodiment of the invention, having a roller 9c, the cylindrical surface of the same is functioning as the head 9b of means for removing water. In accordance with this solution the radius of curvature of the roller 9c can be substantially greater than the radius of curvature R of the head 9a. The advantage is, among other things, the fact that the abrasion of the lower surface of the felt is remarkably diminished, but yet the removal of water is larger compared to a situation with lack of such a separate means for removal of water. The roller 9c can rotate along the movement of the felt 1 or also non-rotably arranged, whereby the roller 9c corresponds a fixed head 9a having a long radius of curvature R. As in the solution in accordance with Fig. 5, also this solution in accordance with Fig. 6 the curved head 9b of means for removing water 9 forms a curved surface 9b, placed beneath the felt 1 and having substantially the same width as the felt, pressing the felt from below. The surface of the roller 9c can also be made out of ceramic, metallic or out of some other abrasive resistant material.

By using the method in accordance with the invention the removal of water from the moving felt 1 is accomplished in a manner that in front of the suction box 4 seen in the running direction 6 of the felt 1, the lower surface of the felt 1 is subjected to a surface 9a, 9b, having substantially the same width as the felt 1, from below, said surface 9a, 9b being exposed to arrange to cause pressure against the lower surface of the felt 1. In addition to the foregoing straight after said location, seen in the running direction of the felt 1, the felt is subjected to a low pressure from below throughout the gaps 8 located in connection with the suction box 4 and redundance water still left in the felt is sucked from the felt 1.

For an artisan in the field it is clear that the invention is not limited to the embodiments presented hereabove, but can vary within the scope of the patent claims herebelow. Thus the location, number and construction of means for removing water ca be other than presented hereabove. The number of means for removing water placed one after the other can be greater than two, for instance three or four or even more.

Correspondingly, it is clear for an artisan in the field that the form and the construction of the head of means for removing water can be any kind of suitable formation.. Thus it is not necessary that the head has the curved formation, but it can be sharp and straight and be situated in straight or inclined position with respect to the lower surface of the felt.

Further, it is clear for an artisan in the field that the head of means for removing water can be arranged to press the lower surface of the felt by means of a spring or corresponding structure.

Additionally, it is clear for an artisan in the field that several the equipment of the invention can be situated one after the other, wherein the efficiency of the removal of water is increased.

Claims

Patent claims:

1. A method for removing water from a moving felt (1), whereby by using the method at least a part of water is removed from below by directing a low pressure to the lower surface of the moving felt (1) ,characterised in that in addition to the low pressure, the lower surface of the felt (1) is exposed from below, at the location in front of the said low pressure seen in the running direction of the felt (1), with a surface (9a, 9b) of separate means for removing water (9), said surface (9a, 9b) having substantially the same width as the felt.

2. The method in accordance with claim 1, characterised in that the lower surface of the felt (1) is exposed from below, at the location in front of the said low pressure seen in the running direction of the felt (1), with a substantially curved surface (9a, 9b) located at the top end of means for removing water (9).

3. The method in accordance with claim 1 or 2, characterised in that after the removal of water by using the curved surface (9a, 9b) of means for removing water (9), water is removed from the felt (1) throughout a suction box (4) placed below the felt by using low pressure .

4. An equipment for removing water from a moving felt (1), whereby the equipment (3) comprise at least a suction box (4) providing low pressure to the lower surface of the felt, wherein the suction box (4) comprises one or several gap(s) (8) placed in transversal direction with respect to the running direction (6) of the felt (1), characterised in that the equipment (3) comprise, in front of the suction box (4) seen in the running direction of the felt (1), at least one means for removing water (9), the head (9a, 9b) of said means (9) being arranged from below the felt (1) to press the lower surface of the felt (1).

5. The equipment in accordance with claim 4, characterised in that the head (9a, 9b) of means for removing water (9) at the top end of said means (9) is substantially curved.

6. The equipment (3) in accordance with claim 4 or 5, characterised in that the head (9a) of means for removing water (9) is rounded in a manner that the radius of curvature (R) is suitably between 10 to 30 degrees.

7. The equipment (3) in accordance with claim 4 or 5, characterised in that the head (9b) of means for removing water (9) is cylindrical surface of roller (9b) located at the top end of said means (9).

8. The equipment (3) in accordance with any of the previous claims characterised in that a discharge chute (10) for removing water is arranged below means for removing water (9).