FI88317B - Adjustable device with turbulence flaps for the discharge duct in the head box of a paper machine - Google Patents

Abstract

The invention relates to a turbulence flap device 30 in the head box of a paper machine, which comprises a plurality of disc-shaped turbulence flaps, which from the inlet edge are fixed in the flow direction in relation to the support structure of the head box turbulence generator or corresponding support structure, and which turbulence flaps are free from the outlet edge and extend in the transverse direction over the entire width of the head box. The turbulence flap device 30 comprises a rigid holder 31, which holder 31 comprises a holder frame 31a and a joint 31b, by means of which the holder 31 is designed to oscillate. The holder 31 has at least two and advantageously a plurality of fixed positions 32a, 32b, 32c, 32d, in which alternative fixed positions 32a or 32b or 32c or 32d the flap 33 can be located in order to adjust the total length L of the flap device 30, as required. <IMAGE>

Description

'38317

Paper machine headbox lip channel adjustable turbulence cap device

Regulation of the turbulent flap for the flap channel in the inlet valve 5

The invention relates to a paper machine headbox lip channel turbulence head device comprising one or more plate-shaped turbulence heads attached in the flow direction at its inlet edge to a headbox turbulence generator or similar support structure 10 and which have

Various turbulence generators and diffusers are used in the headbox of a paper machine to provide a level of diffusion and turbulence suitable for lip flow and lip jet, which is important to achieve good paper formation and a suitable tensile strength / cross direction. Suitable tensile strength ratios vary by paper type. It is known that the fibers of the pulp suspension flowing in the headbox tend to be oriented in the direction of the mass flow, i.e. in the machine direction. The predominance of the machine direction orientation is further enhanced by the speed difference between the pulp jet and the wire. 20 Therefore, with previously known machines, the tensile strength ratio MD / CD tends to become far too high.

Another problem with the prior art headboxes is that the turbulence intensity level in the headbox lip channel has time to decrease in the lip channel before the lip opening and 25 lip jets are discharged so that the tensile strength ratio MD / CD becomes too high for some paper types.

In some respects, the above-mentioned drawbacks have been avoided by placing various turbulence head structures in its lip channel in the headbox. In the hatchback box, the tip clearance of TC (TC = tip clearance) is the main factor influencing the turbulence level. The size of the TC is determined by the lip opening and the length of the needle. On the other hand, the desired 2: ¾ 8 317 TC is determined by the speed of the lip jet and the required level of turbulence. From the above description there is a need to adjust the TC.

In the device according to the invention, a rigid holder is articulated to the turbulence generator. 5 The rigid holder has several alternative mounting positions where the hetula can be placed. The length of the hetula is adjusted by moving it to the replacement cassette and from there back to its new mounting position, e.g. in the keyway.

The paper machine headbox turbulence cap device according to the invention is mainly characterized in that the holder comprises at least two preferably several attachment stations to which alternative attachment positions can be set to adjust the overall length of the comprises a mounting portion 15 corresponding to the cross-sectional shape of the mounting groove of the holder, the cross-sectional shape of which corresponds to the cross-sectional shape of the mounting groove of the holders.

The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, to which, however, the invention is not intended to be exclusively limited.

Figure 1 shows a schematic machine direction vertical cross-section of a headbox with a hatch arrangement according to the invention.

Figure 2 illustrates a problem area in which the turbulence hetero device according to the invention provides a solution.

Figure 3 shows an axonometric view of a turbulence cap device according to the invention.

Figure 4 is a section I-I of Figure 3.

3 8 3 i 7 3

Figure 5 shows another preferred embodiment of the wedge groove shape.

According to Figure 1, the headbox is placed in connection with a double-wire former. Figure 1 shows the breast rollers 10 and 11 and the forming wires 12 and 13 passing over them, which delimit the forming crystal G. From the lip channel 14 of the headbox, a pulp suspension jet J is fed through the lip opening 16 delimited by the tip strip 15 to limit the forming crystal.

The headbox comprises, in the flow direction F of the pulp suspension, a manifold 17, 10 a manifold 18, a compensating chamber 19, a turbulence generator 20 and a lip channel 14, in which there are four overlapping turbulence inputs 30 according to the invention. It is preferred that there are a plurality of articulated hetulates 30 on top of each other, usually 3 to 8 pieces. The lip channel 14 is bounded between a fixed lower lip wall 21 and an upper lip wall 23 pivoting about a horizontal joint 22. The upper lip beam 24 and with it the upper lip wall 23 are arranged with a screw gear 25 to be pivoted about said joint 22. The tip strip 15 delimiting the lip opening 16 above is adjusted by the adjusting spindles 26 and the adjusting gear 27.

Figure 2 illustrates a problem area of the invention. Adjusting the lip opening 20 B changes the conicity of the lip cone. The holes 30a, 30b and 30c fitted inside the lip cone are always at a constant distance from each other. The distance between the ends of the hetulas is the so-called tip clearance TC is constant between each needle depending on the length L of the tips and the adjusted lip opening B size of the lip cone, which determines the conicity of the lip cone. Thus, in order to achieve a certain level of turbulence, the tip clearance TC is determined. Thus, at a certain lip opening, the hetulas should be of a suitable length.

Figure 3 shows a turbulence headlamp device 30 according to the invention. As shown in the figure, the parts of the turbulence headlamp device are shown separately from each other before assembly. Turbu-30 lenssihetulalaite 30 shown in the figure comprises a rigid metal of the holder 31. The holder 31 comprises a holder body 31a and the flow of the input-side end of the hinge 8831 April 7 31b on which the holder 31 is adapted to rotate. The holder body 31a has at least two preferably several attachment stations 32a, 32b, 32c for attaching the needle 33. Thus, the hetula 33 can be attached to one of the alternative attachment positions 32a or 32b or 32c of the holder 31. The holder 31 is a rigid part and preferably metal.

5

The fastening stations 32 are formed of wedge grooves, whereby the needle 33 can be placed from the edge area of the holder 31 in the fastening or wedge groove 32. If it is desired to adjust the length of the needle 33 and change the tip clearance TC, it can be influenced according to the invention by placing the needle 33 32c to the holder 31. The end 33 comprises at its end a fastening part 33a, preferably of the same material and structure, the entire width of the hetula 33, the cross-sectional shape of which corresponds to the cross-sectional shape of the fastening groove 32.

As shown in Fig. 3, the device solution further comprises a locking piece 34, which can be fitted 15 after the needle 33 has been inserted into the fastening groove 32 at the end edge of the holder 31.

The locking piece 34 may be metal.

Fig. 4 shows a section I-I of Fig. 3 with the needle mounted in position on the position 20 32a of the holder 31. As shown in the figure, the mounting grooves have a rectangular cross-section.

Figure 5 shows another preferred embodiment of the mounting groove shape of the exchange stations 32 of the holder 31. In the embodiment, the mounting grooves 32a, 32b, 32c have a cross-section 25 on each side of the central axis X of the holder.

Claims (3)

1. A turbulence tab assembly (30) in the inlet carriage of a paper machine comprising several disc-shaped turbulence tabs which are fixed from the input edge in the flow direction in connection with the support structure of the inlet tray turbulence generator or the corresponding support structure across the out-of-bias tabs and are completely free from each other. the width of the inlet carriage, and that the turbulence tab assembly (30) comprises a rigid holder (31), which holder (31) comprises a holder body (31a) and a hinge (31b), by means of which the holder (31) is arranged to pivot. characterized in that the holder (31) comprises at least two, advantageously several, fastening positions (32a, 32b, 32c, 32d ...), in which alternative alternatives (32a or 32b or 32c or 32d ...) the tab (33) can be positioned to control the total length (L) of the tab assembly (30) in the desired manner and that the fastening (32a, 32b ...) of the holder (31) of turbulence flaps the north end (30) consists of a fastening latch in which the tab can be positioned from the side of the hobs (31) and the end of the tab (33) comprises a fixed part (33a) corresponding to the cross-sectional shape of the fastening latch of the hob (31), the cross-sectional shape of the fastening part (33a) corresponds to the cross-sectional shape of the fastening latch (32) of the hooks. Turbulence tab assembly (30) according to claim 1, characterized in that the cross-sectional shape of the holder fastening latch (32) is rectangular. Turbulence tab assembly (30) according to claim 1, characterized in that the cross-sectional shape of the fastening bar (32) has the shape of a half salmon tails.