FI113064B - Arrangements at the flow channels in the paper machine's inlet box - Google Patents

Description

113064

PAPER MACHINE BOX FLOW DUCT

The present invention relates to an adjusting sleeve for controlling fiber mass flow 5 in a hydraulic headbox of a papermaking machine, consisting mainly of a large diameter inlet tube and associated bypass tube, headbox body, same or different groups of and this lip gap.

The function of the manifold is to provide a uniform distribution of the mass flowing from the inlet pipe over the width of the headbox. There are several distribution channels side by side and overlapping. Their apertures have a much smaller cross-sectional area than the inlet pipe. This results in a fairly even flow through the individual distribution channels. The mass flow rate in the individual manifolds is correspondingly higher than the mass flow rate in the inlet pipe.

The manifolds are generally of circular cross-section and have multiple lengths, usually at least 5 times the diameter. They are discharged into the headbox :, 25 intermediate chambers where the individual flows are calmed. Partial flow quenching is achieved by gradually increasing the diameter of the manifolds, e.g. in two steps. It is also possible that the manifolds are mostly '·' 'slightly conical.

*> * V * 3 0 After the intermediate chamber, the mass flows through the turbulent piping • into the lip of the headbox and from there to the lip of the headbox: through a paper machine wire.

• ·, 35 The structure of the turbulence pipeline is essentially the same as that of the * * manifold, ie it may suitably consist of several overlapping and parallel pipes. However, there may be more turbulence tubes than manifolds to ensure maximum performance. Their main function is to provide turbulence in the mass flow that effectively disrupts any bundles and deposits of fibers that may have formed in the intermediate chamber that would otherwise be visible in the finished paper. cloudiness ..

Even if the headbox flow ductwork, as a whole and in principle, is properly designed, its implementation may result in manufacturing errors which can cause interference in the mass jet discharging from the lip duct and thus affect the transverse thickness profile of the paper being manufactured. There may be other disturbances in the outflow of the pulp which have been known to be minimized, for example by means of additional flow arrangements led to the headbox.

It is an object of the present invention to provide a control sleeve by means of which the uniformity of the mas-20 clay flow into the headbox lip channel is relatively simple to control over the entire width of the headbox in both quantity and speed.

This object is achieved by the invention, characterized in that one or more manifolds of at least three parts or. a special, removable adjusting sleeve is fitted to the mouth of the turbulence tube in the downstream direction.

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The invention will be described in more detail below with reference to the accompanying drawing '30, in which: FIG. 1 schematically illustrates a longitudinal sectional view of a papermaking machine for the flow piping to which the invention relates, '35, FIG. 2 shows the same headbox. Fig. 3 shows an alternative solution to the arrangement shown in Fig. 3, Figs. 5 and 6 show two different possibilities of adjusting a sleeve according to the invention. design.

10

In Fig. 1, reference numeral 1 denotes the headbox inlet pipe through which the mass is introduced into the headbox. Reference numerals 2, 3 and 4 denote schematically the headbox body parts which are not specifically covered by the invention. The lip-15 channel in the headbox and its lip are designated by reference numerals 5 and 5a.

The manifolds forming the manifold are denoted by reference numeral 6 and the turbulence tubes forming the turbulence manifold by reference numeral 7.

2, the flow control system assembly according to the invention is illustrated in figure; ta 1 more clearly. The inlet tube 1 extends as it is known perpendicularly. just across the width of the headbox. By means of a bypass pipe la. it is possible to ensure the most even pressure possible throughout the support * '.25 for the rest of the length 1. Inlet pipe 1 forks a horizontal bar · *. a plurality of manifolds 6, which may be several on top of one another and a rin tumbler. Their orifices are provided with adjusting sleeves according to the invention, designated by reference numeral 14. The inner diameter of the second section 9 of the manifold following each adjusting sleeve - 30 is greater than or equal to or less than the inside diameter of the adjusting sleeve 14. The manifold continues for a third period 10, which in turn has an inner diameter greater than the inner diameter of> 9 · · ··· *.

♦ · 4 113064

The manifolds 6 open into an intermediate chamber 3 for combining and quenching the separate flows from the individual tubes. The intermediate chamber 3 may be uniform over the entire width of the machine. In its front wall, which is opposite the flow direction 5, there is a row of adjusting sleeves 14, as described above for the manifold group. Through these, the pulp enters a turbulence conduit formed by the turbulence tubes 7, the purpose of which is to equalize the micro-distribution of the fibrous pulp flowing through them, that is, to break down any fibrous support deposits in the pulp.

The intermediate chamber 3 is fitted to the body structure of the headbox 2,4 so that it can be detached therefrom either as a whole or on its upper part, for example for cleaning or replacement of the adjusting sleeves 15. This removal is most conveniently carried out upwards or sideways, for which the frame of the chamber 3 as well as the other headbox body is provided with suitable guides. The intermediate chamber 3 may also be wedge-shaped, as shown.

Fig. 3 is a partial sectional view of the beginning of the manifold of Fig. 2, fitted in accordance with the invention. with adjusting sleeves 14 and positioning of adjusting sleeves 14 in the first part of the manifold 8. As such, the manifold, ··. 6 is of the same type as in several headbox inventions, e.g.

. \ 25 The three-stage so-called "filed" in the application is 91 91 55. stepdif- • ». ·. fusori. The essential difference with the cited structure is that: ·, the manifold of the present invention consists of at least three

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8, 9, 10, of which the first part 8 has a larger inside diameter D1 than the inner diameter and D2 of the second part 9 and also .. # 30 the inner diameter and D3 of the third part 10 is larger than the inner diameter D2 of the second part. It is possible to fit in the first part pipe 8 an adjusting sleeve 14 according to the invention, the inner diameter of which may be greater, smaller or equal to the inner diameter D2 of the second part. The outer diameter of the adjusting sleeve 14; ··· 35 dl may be greater than or equal to the inner diameter D2 of the second portion 9. The adjusting sleeve 14 may be secured in place by, for example, a press fit, a thread or a nail joint, so that it is easily removable and replaceable if necessary.

5

Figure 4 illustrates the possibilities of controlling the flow through the two single manifolds of the sleeve assembly according to the invention. In Fig. 4, two sleeve types 14a and 14b of different shapes 10 are fitted in the front part 8 of the manifold 6. The sleeve 14a is straight in its inner part and the inner diameter d2 of the sleeve is equal to the inner diameter D2 of the second part 9 of the manifold. The sleeve 14b is tapered in its inner part and has a smaller inner diameter smaller than the inner diameter D2 of the second part 9 of the manifold.

15

Figures 5 and 6 show some embodiments of the invention as sleeve types 14c and 14d, which are characterized by a shorter or longer partial conicity in the region of their inner part.

The types of adjusting sleeves shown in Figures 3, 4, 5 and 6 are merely exemplary of part embodiments of the invention. There is also; It is understandable and natural that the adjusting sleeves can be positioned * · anywhere along the width of the headbox according to the mass jet that is discharged from the lip of the headbox: 25 flow profile or unevenness of finished paper. desta can be stated or inferred. The adjusting sleeve may be substantially circular in shape or substantially non-circular in shape according to the shape of the manifold or turbulence tube.

Although the foregoing description of the patent drawing and its drawings * relates primarily to the manifold 6 and the associated adjusting sleeve 14, 14a, 14b, 14c, 14d, the same aspects and explanations also apply to the turbulence tubes 9 forming the headbox turbulence portion and : 35 take the sleeves 14.

113064 Accordingly, the inner diameter 12 of the second section 12 of the turbulence tube 7 following each adjusting sleeve 14 is greater than or equal to or less than the inner diameter of the adjusting sleeve 14. The Turbu-5 lance tube continues for a third period 13, which in turn has an inner diameter greater than the inner diameter of period 12.

The turbulence tubes 7 ultimately determine how well the aft box 10 performs its function of feeding the pulp into the pulp. Particularly difficult is the friction caused by the side walls of the headbox to the mass flow. Therefore, the most extreme turbulence tubes on either side of the headbox flow range require the use of various types of adjusting sleeves 15 according to the invention to achieve the desired result. This can only happen through experimentation. The experiment is facilitated by the fact that the sleeves are compact and easy to handle.

It is also advantageous to apply the invention when the flow through the pe-20 box has to be substantially increased or decreased, for example, to match the changed working speed of the paper machine.

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Claims (10)

A control sleeve for controlling a fiber mass flow in a hydraulic inlet carriage of a paper machine, said inlet carriage comprising a large diameter inlet tube (1) and a bypass tube (1a) connected thereto, the inlet tray body (2,4), distribution pipes for pulp (6) having the same or different diameter and branching from the inlet pipe, at least one intermediate chamber (3), a group or groups of turbulence pipes (7) of the same or different diameter, and the inlet carriage's lip channel (5) and its slot ( 5a), characterized in that the orifice of one or more, at least three parts consisting of distribution pipes (6) or turbulence pipes (7), in the part which in the flow direction is the first part, is provided with a special detachable control sleeve (14, 14a, 14b, 14c, 14d). Control sleeve according to claim 1, characterized in that the outer dimension (d1) of the control sleeve 15 (14,14a, 14b, 14c, 14d) is larger than the inner diameter (D2) of the other part (9,12) of the distribution or turbulence tube. Control sleeve according to claim 1, characterized in that the outer diameter (d1) of the control sleeve (14,14a, 14b, 14c, 14d) is equal to the inner diameter (D2) of the second part of the distribution or turbulence tube (9, 12 ). ; . Control sleeve according to claim 1, characterized in that the inner part of the control sleeve 'V (14,14a, 14b, 14c, 14d) is substantially cylindrical. * 25 Control sleeve according to claim 1, characterized in that the inner part of the control sleeve (14,14a, 14b, 14c, 14d) is substantially tapered or partially tapered. * · V : 6. Control sleeve according to claim 1, characterized by the diameter (d2) of the control sleeve (14,14a, 14b, 14c, 14d) with respect to flow direction; The outlet outlet is larger than the inner diameter (D2) of the first portion (8, 11) of the distribution or turbulence tube. • *> Control sleeve according to claim 1, characterized by the diameter (d2) of the control sleeve (14,14a, 14b, 14c, 14d) with respect to the flow direction outlet is smaller than the inner diameter (D2) of the distribution or turbine. · The first part of the lens tube (8,11). 113064 40 ' Control sleeve according to claim 1, characterized by the diameter of the dummy (d2) of the control sleeve (14,14a, 14b, 14c, 14d) with respect to the flow direction outlet is equal to the inner diameter (D2) of the first part of the distribution or turbulence tube ( 8.11). 5 Control sleeve according to Claim 1, characterized in that the control sleeves (14,14a, 14b, 14c, 14d) are arranged mainly in distribution and / or turbulence pipes (6, 7) which are almost edge portions of the inlet carriage. Intermediate chamber (3) for an inlet carriage according to claim for equalization of the individual currents from the distribution pipes (6), characterized in that the chamber part (3) is removable from the other body (2,4) of the inlet bar so that it is possible to adjust the control sleeves ( 14.14a, 14b, 14c, 14d). »* ·» I · t »» »