FI60740C - HYDRAULISK INLOPPSLAODA FOER PAPPERSMASKIN - Google Patents

Description

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Patent- och registerstyrelsen 'Antökan utligd oeh uti.ikrifi.n publtcerad 30.11. ol (32) (33) (31) Privilege requested — Begird prloritet (71) Valmet Oy, Punanotkonkatu 2, 00130 Helsinki 13, Finland-Finland (FI) (72) Erkki Koski, Jyväskylä, Finland-Finland (Fl) (7) * 0 Forssen & Salomaa Oy (5 * 0 Paper machine hydraulic headbox - Hydraulisk inloppsläda för pappersmaskin

The invention relates to a hydraulic headbox for a paper machine, comprising a manifold transverse to the main flow direction of the pulp suspension and then successively one or more coils and / or lamella parts with a flat cross-sectional area and one or more flow chambers whose flow chamber terminating in the lip gap of the headbox is substantially uniformly tapering in the flow direction of the pulp suspension.

With regard to the state of the art related to the invention, reference is made to Swedish Announcement 367,031 (JM Voith GmbH), Finnish patent applications 352/69 and 3796/74 (Beloit Corporation) and the book Technische Strömungslehre, Bruno Eek, 5th edition, Springer-Verlag 1958, pages 188- 191.

It is already known in the hydraulic headboxes of paper machines to use lamellar parts or tubular coils as "rubbing parts", which prevent harmful transverse flows and provide microturbulence homogenizing the pulp suspension. In addition, in previously known headboxes, the part terminating in the lip-slit is usually tapered with respect to the flow direction.

2 '0740

In previously known headboxes, said tubes or lamellae also form a tapered portion in that their outlet side opens into a flow chamber whose flow cross-section at this point is larger than the flow cross-section of the chamber into which the outlet side of said tubes or lamellas opens, remains constant. The manufacturing cost of such a lamella part or a tube coil part becomes relatively high, and in these parts it is not possible to take advantage of the fact known e.g. from the above-mentioned literature reference that the accelerating flow of the converging chamber improves the velocity profile uniformity.

The object of the present invention is to eliminate the above-mentioned drawback and to provide a headbox structure which is as simple as possible in structure and such that the above-mentioned speed profile equalization means can be advantageously used. To this end, the invention is mainly characterized in that the preceding chamber separated from said lip chamber ending in the lip gap by a lamella part and / or a tube radiator part is substantially uniformly tapered in the flow direction of the pulp suspension.

The invention will now be described in detail with reference to an embodiment of the invention shown in the figure of the accompanying drawing, to which, however, the invention is not intended to be limited.

Figure 1 shows a schematic cross-section of the headbox in the machine direction.

Figure 2 shows section II-II in Figure 1.

Figure 3 shows a section III-III in Figure 1.

Figure 4 shows the velocity profile of a compensating chamber arranged according to the invention on its inlet and outlet side.

Figure 1 schematically shows the breast roll 10 of a paper machine and its overlying forming wire 11. The lip gap 19 of the headbox opens in a known manner close to the breast roll 10. The headbox-related pulp suspension feeders are shown schematically in block 13. These devices 13 3 60740 feed the pulp suspension to a manifold 21 transverse to the headbox flow direction.

After the tube coil 15, a tapered flow chamber 16 is arranged according to the invention, which has no tubes or lamellae. After the flow chamber 16, in the flow direction x, there is a lamella part 17 known per se, which consists of vertical lamellae 22 or corresponding lamellae slightly inclined with respect to the vertical. After the lamella part 17 there is a lip part 20 of the headbox known per se, which is also tapered. The lip portion abuts the headbox side walls 23, the upper lip portion 18a, and the lower lip portion 18b. The upper lip portion 18a is fitted with a horizontal joint 25 to the body portion of the headbox for pivoting in a vertical plane to adjust the size of the lip gap 19. Adjustment devices for this purpose are schematically shown in block 12. The lower frame of the headbox is indicated by reference numeral 14.

As stated, these flow chambers 16 and 20 without lamellae or the like are preferably uniformly tapered with respect to their flow direction. The convergence angle of the first flow chamber 16 is denoted by a and the convergence angle of the second chamber 20 by $.

In the converging chambers 16,20 an accelerating flow is generated which improves the uniformity of the velocity profile of the flow F in the height direction y. In this context, reference is made to the literature reference mentioned at the beginning. Figure 4 is this equalization the effect illustrated by plotting the flow chamber 16 of the inlet-side velocity profile of P ^ (x = 0) and the output side of the speed profile P2 (x = xq) In view of the speed profiles of Figure 3 P ^ and P ^ is to be noted that nopeuspro-Fiilin is balanced under the influence of the converging flow cross-section, at the same time the shear forces on the liquid also decrease not only in the immediate vicinity of the walls of the flow chamber. The most preferred magnitude of the angle α is about 2 ° -15 ° and the angle α is preferably somewhat larger than the angle 8.

The invention is in no way limited to the embodiment described above by way of example only, and its details may vary within the scope of the inventive idea defined by the following claims.

Claims (2)

4,60740 1. Hydraulic inlet for a paper machine and in the case of an inlet for mass suspension of interest (x) for the purpose of transfer (21) and for a further period of the same (for example) 15 the chambers (16,20), the light chamber (15) and / or the lamella part (17) the same chambers (16,20) and the account (x) 20) in the case of mass suspension (x) and in the case of a solid state (S), the transverse effect is obtained, in which case the number 16 of the chamber (20) of the lamellar part (s) ) is the mass suspension of the stricter (x) the strata of the mass suspension (ex) and the utilization lamellas, rörbatterier eller dylikt huvudsakligen i syfte att förbättra jämnheten av strömningens (F) hastighetsprofil (P) i strömningstvärsnittets höjdriktning (y). A hydraulic headbox for a paper machine, comprising a manifold (21) transverse to the main flow direction (x) of the pulp suspension therein and then successively one or more tubes (15) and / or lamellae (17) with a flat cross-sectional surface and one or more flow chambers (16.20), which tube coil (15) and / or lamella part (17) and flow chambers (16.20) are substantially parallel to each other in the main direction (x), the flow chamber (20) terminating in the headbox lip gap (19) being substantially flat in the flow direction (x) of the pulp suspension converging (3), characterized in that the preceding chamber (16) separated from said flow chamber (20) terminating in the lip gap by the lamella part and / or the tube coil part (17) is also substantially uniformly tapering (ot) in the flow direction (x) of the pulp suspension, without lamellae, tube coils or the like for the main purpose of the flow (F) velocity profile (P) t improving the flow in the height direction of the flow cross - section (y). Headbox according to claim 1, characterized in that said angle of convergence (α) of the chamber (16) is between 2 ° and 15 °. An insert according to claim 1, which comprises a chamber (16) having an additional tip (a) of 2 ° -15 °.