FI119824B - Method in an arrangement for feeding pulp in a web forming machine and arrangement for feeding pulp in a web forming machine - Google Patents

Description

119824

Method for Dispensing the Injection Matter of a Web-Making Machine and the Injection Matter of a Web-Making Machine

ENGINEERING

The invention relates to a method according to the preamble of claim 1.

10

The invention also relates to a rigid fluid according to the preamble of claim 7.

BACKGROUND ART

In web forming machines such as paper, board or tissue machines, the pulp is fed directly to the headbox after cleaning, or through the container between the cleaning and the headbox to the headbox. In the direct feed, the vibrations in the mass flow are damped in the headbox. In a * i * 20 feed through the hopper, the vibrations in the mass flow are damped in the hopper, which forms a damping hopper.

Patent 116147 discloses a process and mixer for mixing streams in a papermaking process * · «. In the invention, the first flow is passed through 25 tubes and turbulence is created therein by means of the molded pieces «« · »* · * * * inside the tube. The mixing zone of the mixer comprises • · · • * '···' inlets on the inner surface of the tube for supplying a second flow from the outside supply channel of the tube to the first flow, whereby the flows are mixed by turbulence caused by moldings. According to a preferred embodiment: * · * · 30, the at least one shaped body comprises an inlet port. The mixer is placed in the pulp feed tube between the sieve and the headbox.

2 119824 FI Patent 111284 discloses a method and apparatus for feeding a chemical into a liquid stream. The retention chemical is fed through a special chemical mixer into a fiber suspension fed into the headbox of a papermaking machine or similar web forming device. The mixer is positioned less than 10 meters from the head-5 duct to the approach tube between the machine screen and headbox. A multi-component retention chemical can and must be supplied at different points in the headbox approach piping. From a formulation point of view, it is good to feed the retenium thiochemicals in two steps. Those relaxants, e.g., polymer-based retention agents that form large flocs, are fed either before or after the headbox screen. It is clear then that the flocs formed by them begin to disintegrate due to both turbulence in the headbox feed tube and the long delay. Subsequently, another retention agent, e.g. a mineral-based retention agent, is fed as optimally as possible near the headbox so that the flocs formed by them to form the actual wire retention 15 remain intact up to the wire. In particular, it is possible to use the method and apparatus disclosed in the patent for feeding the latter retention agent.

: DE-A-40 05 281 discloses a jai # 20 container located before the headbox. The manifold replaces the headbox manifold. The mass flow is fed into the distribution tank after purification, i.e. the strainer, into a manifold, where it is distributed to the headbox feed tubes and diluted with dilution water in the headbox feed tubes.

• * * • • • • • · · 25 The machine screen and headbox shown in the aforementioned FI Patent 116147 are • •! In addition to retention agent feed equipment installed in the piping, a damping tank is required for the mass supply line between the screen and the headbox: • to dampen pressure fluctuations in the mass flow. These pressure fluctuations in the mass flow are caused, for example, by the wings of the pumps. The pressure fluctuations in the mass flow 30 are particularly detrimental to the flat wire machines where they cause • * · · • ;. · · Indicate inhomogeneity of the web being formed. In the prior art 3 119824, the retention material supply apparatus and the silencing tank are separate apparatuses. For both devices, there must be space on the feed line between the machine screen and the headbox, and this can cause problems, especially in rebuilds. Replacement equipment generally does not provide a sufficiently long straight tube section to accommodate the attenuation tank and retention agent supply equipment. This results in a situation where existing devices need to be moved to a damping tank and retention agent supply system to solidify the space. The transfer of existing equipment entails significant additional costs.

SUMMARY OF THE INVENTION

The main features of the method according to the invention are set forth in the characterizing part of claim 1.

The main features of the device according to the invention are in turn described in the characterizing part of claim 7.

The solution according to the invention integrates a retention agent feeding apparatus · * · ,. a tank, which may be a silencing tank or a distribution tank. This saves space V 20 in rebuilds since the space between the screen and the headbox requires only space for the tank. Further, the solution according to the invention is more advantageous in the manufacturing process; : Cost compared to a separate tank and additive mixing equipment.

• · • · * ·

C: BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows a pulp feed-in arrangement into the back box of a forming machine.

Figure 2 shows an enlarged view of the container shown in Figure 1.

30 φ • · *

Figure 3 is an enlarged view of the mixing portion of the container shown in Figure 2.

4, 119824

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 illustrates a pulp feeder arrangement into the stern-box of a forming machine. The mass flow M is supplied by pump 10 via machine screen 20 to the tank 100 and then to the headbox 30. The figure also shows means for supplying the additive L to the mixing section 120 of the tank 100, where the additive L mixes with the mass flow M.

Figure 2 is an enlarged view of the container 100 or damping container shown in Figure 1. The lower part of the damping vessel 100 has an inlet 110 from which mass M is fed to the damping vessel 100. The inlet 110 is followed by a mixing section 120, where the additive L is introduced into the damping the lower portion of the reservoir portion 140 has a hole plate 200 and the central portion has an outlet 150 for the mass M. The upper portion of the cylindrical reservoir portion 140 is filled with compressed air P to form a gas spring for the pulp in the damping reservoir 100.

The mixing section 120 of the damping tank 100 may be formed as an integral part ···· · ***: the mixing tank 100 or a separate, removable section from the mixing tank 100. In the latter case, the lower part of the damping tank 100 is followed flange,; to which the mixing portion 120 can be attached.

Figure 3 shows the basic structure of mixing section 120 without the equipment associated with the supply of additive L. The mixing portion 120 comprises a cylindrical or conical tube 121 through which a mass flow M is passed. The inner periphery 122 of the tube 121 has: *; fitted with moldings 123a, 123b, 123c, the tube having a corrugated cross-section at this point. The number, shape, dimensioning and mutual position of the moldings are designed on a case-by-case basis. Preferably, there are at least three moldings 123a, 123b, * ···· 123c and are disposed on the inner circumference 122 of the tube 121 at equal intervals 5119824 and at substantially the same position along the longitudinal axis of the tube 121 When viewed from the direction of flow of the mass M, the area of the wedge-shaped shaped body is initially approximately zero, since its leading edge is a circumferentially linear surface. As it proceeds in the direction of flow, the linear surface grows radially into a 5-sector cross-section of the circular ring. As the mold body grows in the radial direction of the tube 121, it begins to shrink in the circumferential direction, whereby the trailing edge of the mold body is again linear. In this case, the solids in the flow, such as fibers, for example, do not adhere to it, but such a shape is substantially barrier-free and thus very clean. The additive L can be introduced into the tube 10121 either from the feed holes provided just before the mold pieces 123a, 123b, 123c or from the feed holes which are followed through the mold pieces 123a, 123b, 123c. Molds 123a, 123b, 123c create turbulence which improves the mixing of the additive with the pulp suspension.

The additive L is preferably a retention chemical. The perforation plate 200 located in the damping container 100 after the mixing portion 120 also facilitates effective mixing of the retention agent with the mass flow M. The distance between the mixing portion and the perforated plate 200 is so small that the retention agent is not yet adhered to the fiber. The additive L then mixes very well with the mass flow M *, whereby the pressure drop in the mixing portion 120 can be dimensioned to be low. The solution according to the invention also saves energy in comparison with techno · ·; ankle level solution.

The solution according to the invention can also be used in the situation described in the aforementioned DE publication 4005281 in which the headbox manifold is replaced by a manifold located in the front headbox. . The additive mixer is then traced to the · · * · · * in the above mentioned container.

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IM I

IM

Only some preferred embodiments of the invention have been described above, and it will be apparent to those skilled in the art that various modifications may be made thereto.

MM

•: · · · Within the scope of the appended claims.

Claims (12)

Method in an arrangement for feeding pulp in a web feeding machine, in which a pulp flow (M) is measured with a pump (10) via a screen (20) and a container 5 (100) for an inlet carriage (30), characterized in that , that a mixing portion (120), where an additive (L) is measured to the mass flow (M), is formed in the container (100). Process according to claim 1, characterized in that the mixing portion (120) is formed as a fixed part of the container (100). 10 Method according to Claim 1, characterized in that the mixing portion (120) is formed as a separate, detachable part of the container (100). 4. A method according to claim 1, characterized in that a damping container is formed by the container (100), with which vibrations in the mass flow (M) are damped. 5. A method according to claim 1, characterized in that a dividing container is formed by the container (100), with which the mass flow (M) measured is measured. 1. The travel carriage (30), is divided into several partial flows. * ·· 20 ···· • · · • V 6- Method according to claim 4, characterized in that in the container (100), a heeled disc (200) is formed in a space after the mixing portion (120). · 1 φ • ·· * ·· • · * ··· 1 An arrangement for feeding pulp into a web forming machine comprising at least one pump (10), a machine screen (20), a container (100) and an inlet carriage, wherein the pulp flow ( M) measured with the pump (10) via the machine screen (20) and • · * ·· ** container (100) for the inlet carriage (30), characterized in that the container (100) ..1 · 1 comprises a mixing portion (120) , where there are means for feeding an additive ··· * ... 1 (L) to the mass flow (M). : 30 ··· · 119824 Feeding arrangement according to claim 7, characterized in that the mixing portion (120) is a fixed part of the container (100). Feeding arrangement according to claim 7, characterized in that the mixing portion (120) is a separate, detachable part of the container (100). Feeding arrangement according to Claim 7, characterized in that the container (100) is a damping container, with which vibrations in the mass flow (M) are damped. 10 Feeding arrangement according to claim 7, characterized in that of the container (100) is a dividing container, with which the mass flow (M) measured in the inlet carriage (30) is divided into several partial flows. Feeding arrangement according to claim 10, characterized in that the container (100) comprises a heeled disc (200) placed in a space after the mixing portion (120). ·· • * • ·· • '· ··· • · m • ♦ • · • · • m • · · • · ♦ • * · mmm • · • ·· • · · m • · • »• ♦ • »· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·