Device in a paper machine

Abstract: The invention concerns an equipment in a paper machine for collecting the mist that is produced in the spraying of high-pressure water employed in the washing of a wire of a paper machine out of contact with the wire (H). The equipment comprises such an inlet duct (12) extending a cross the wire width whose central axis (X) is at an oblique angle (α) in relation to the direction of running of the wire (H). The equipment fur ther comprises a jet guide (13) in connection with the inlet opening (12a) of the inlet duct (12), said jet guide being a plate-shaped part connected to the frame (11) by means of adjust ing members (14) and operating as an air closure and as a regulator of suction capacity. The position of the jet guide (13) can be adjusted relative the surface plane of the wire (H) by means of the adjusting members (14).

Description: The invention concerns a device in a paper machine for removal of the mist that is produced in high-pressure washing in a paper machine, according to the preamble of Claim 1. In prior art, the use of negative pressure is known in removal of the mist that is produced in high-pressure washing out of contact with the wire. However, the prior-art solutions of equipment have not operated satisfactorily, and, therefore, gathering of dirt and impurities around the wire guide rolls and other auxiliary equipment has been a constant problem. In the present application, attempts have been made to find a solution for the above problem of impurities, and in the invention it has been realized to form a device that gathers mist, i.e. a mist trap, so that it is provided with an adjustable profile bar extending across the wire width, whereby, by regulating the position of the profile bar, the suction of the mist trap can be regulated. In the invention, it has been realized to provide the device with a duct portion that is at an oblique angle in relation to the direction of running of the wire. Thus, in the invention, it has been realized to take advantage of the impulse received by the mist from the wire and of the direction of the mist in the collecting of the mist into the device. The device in accordance with the invention for removal of the mist produced out of high-pressure washing of the wire, out of contact, with the wire is mainly characterized in that the equipment comprises such an inlet duct extending across the wire width whose central axis is at an oblique angle in relation to the direction of running of the wire, and that the equipment comprises a jet guide in connection with the inlet opening of the inlet duct, said jet guide being a plate-shaped part connected to the frame by means of adjusting members and operating as an air closure and as a regulator of suction capacity, whereas the position of the jet guide can be adjusted in relation to the surface plane of the wire by means of the adjusting members. In the following, the invention will be described with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying drawings, the invention being, however, not supposed to be confined to said embodiments alone. Figure 1 illustrates high-pressure washing in accordance with the prior art, and in the figure the direction of the mist jet is illustrated. Figure 2 is a schematic illustration of a solution of equipment in accordance with the invention used for removal of the mist produced in high-pressure washing of a lower wire. Figure 3 shows the location of a mist remover in accordance with the invention in connection with a Speed-Former in a paper machine. Figure 4 is a more detailed illustration of a solution of equipment in accordance with the invention, and what is shown is a longitudinal view of the equipment for removal of the mist produced in high-pressure washing, viewed in the machine direction. Figure 5 shows the mist-removing equipment as viewed in the direction K₁ indicated in Fig. 4. In Fig. 1 the problem area of the invention is illustrated, and what is shown is a high-pressure washing device K fitted in connection with the lower wire in a paper machine, a high-pressure washing jet being passed through the jet pipe R in said washing device onto the lower face of the wire H. The jet pipe R is oscillated, whereby the washing jet can be directed efficiently out of the nozzle openings in the jet pipe R to different points on the wire. As is shown in Fig. 1, the mist S is directed obliquely to the normal of the wire plane. Thus, the direction of the mist S is affected by the direction of running of the wire, by the wire speed, by the initial velocity produced for the jet, and by the initial direction of the mist. As is shown in Fig. 2, in the collecting of the mist S, it has been realized to make use of a solution of equipment wherein the mist S is collected in a space D in the interior of the frame 11 of the device 10 through an inlet duct 12 extending across the wire width. The central axis of the duct is placed at an oblique angle α in relation to the direction of running of the wire H. The angle is advantageously about 30...60°, and preferably about 45°. Thus, in the invention, it has been realized to take advantage of the direction of the mist in the collecting of the mist. During its passage through the wire H, the direction of the mist is changed, and the mist receives a transverse component for its direction from the wire H. Thus, on the other side of the wire, the mist jet is at a substantially oblique angle in relation to the direction of running of the wire, said angle being about 45° in relation to the direction of running of the wire H. The direction of the mist varies depending on the wire speed. According to the invention, the equipment 10 comprises a jet guide 13 attached to the frame 11 and placed at the proximity of the inlet duct 12. The jet guide 13 is attached to the frame 11 of the device 10 by means of adjusting screws 14. The jet guide 13 is a plate-shaped component, whose function is to act as an air closure and as a regulator of the suction capacity. The jet guide 13 also acts as means of protection, preventing any contact between the frame 11 and the wire H. When the adjusting screws 14 are loosened, it is possible to adjust the distance of the jet guide 13 from the wire H face accurately. The device further comprises a collector trough 15 for exhaust water, and a drain pipe 16 for same. Through the drain pipe 16, the exhaust water or equivalent condensed and gathered in the exhaust trough 15 is drained off. Into the space D in the interior of the frame 11 of the mist remover 10, a suction duct 17 is opened, which may communicate with the outlet duct 18 of the overall air-conditioning of the paper machine. The exhaust capacity of the device is 4...6 m³ per second. Fig. 3 shows a preferred location of a mist remover in accordance with the invention in connection with the inner wire of a Speed-Former in a paper machine. The equipment 10 is placed on the return run of the inner wire H at the point A, in the way shown in Fig. 3. Fig. 4 is a more detailed illustration of the device 10 in accordance with the invention for removal of the mist produced in high-pressure washing. In Fig. 4, the device 10 is shown as viewed in the machine direction of the paper machine. The jet guide 13, which extends across the wire width, is attached to the frame 11 by means of screws 14, the suction capacity being regulated by means of said jet guide 13 and said jet guide 13, at the same time, operating as an air closure, permitting an efficient removal of mist. In the interior of the frame 11, there is a collecting space D, into which a suction duct 17 is opened. In the space inside the frame 11,, a collector trough 15 is provided for the exhaust water, an exhaust pipe 16 being opened into said trough 15, through which pipe 16 the water gathered in the collector trough 15 can be drained. In Fig. 5, the equipment is shown as viewed in the direction of the arrow K₁ shown in Fig. 4. As is shown in the figure, the frame includes an inner space D, and in the space D a collector trough 15, into which the end 12a of the inlet duct 12 is opened. The central axis X of the inlet duct 12 is placed at an oblique angle in relation to the direction of running of the wire H. Thus, efficient use is made of the mist-directing effect of the wire. The mist is directed straight into the inlet duct 12 without a necessity to produce additional changes in the direction of the mist inside, or at the proximity of, the device. By means of the adjusting screws 14, the position of the jet guide 13, preferably of a plastic rib at the inlet edge, in relation to the wire H face is adjusted. In the figure, a screw 14 is shown, by means of whose loosening it is possible to adjust the jet guide 13, preferably a plastic rib, to the desired height position in relation to the surface plane of the wire. The frame 11 is connected with a screw device, by whose means the position of the whole device 10 in relation to the wire H draw can be adjusted.

Claims: Equipment in a paper machine for collecting the mist that is produced in the spraying of high-pressure water employed in the washing of a wire of a paper machine, out of contact with the wire (H), said equipment comprising a frame (11) extending across the wire width and therein an inlet duct (12), whereby, by means of a negative pressure produced inside the frame (11), the mist produced in the washing of the wire is sucked through the inlet duct (12), and said equipment comprising a collector trough (15) or equivalent in the interior space in the frame (11), whereby the water gathered in the collector trough (15) can be removed out of the collector trough (15) through a drain pipe (16), characterized in that the equipment comprises such an inlet duct (12) extending across the wire width whose central axis (X) is at an oblique angle (α) in relation to the direction of running of the wire (H), and that the equipment comprises a jet guide (13) in connection with the inlet opening (12a) of the inlet duct (12), said jet guide being a plate-shaped part connected to the frame (11) by means of adjusting members (14) and operating as an air closure and as a regulator of suction capacity, whereas the position of the jet guide (13) can be adjusted in relation to the surface plane of the wire (H) by means of the adjusting members (14). Equipment as claimed in claim 1, characterized in that the adjusting members (14) are adjusting screws. Equipment as claimed in claim 1, characterized in that the central axis (X) of the inlet duct (12) is at an angle (α) in relation to the direction of running of the wire and to the wire plane, while the angle (α) is advantageously in a range of 30...60° and preferably about 45°.

Inventors: KARI TUOMO, KIVIRANTA SEPPO, KARI, TUOMO, KIVIRANTA, SEPPO
Applicants: VALMET PAPER MACHINERY INC, VALMET PAPER MACHINERY INC.
Application year: 1991
Main classification: D21F1
IPC codes: D21F1