FI117601B - Device and method of an outlet box in a paper or cardboard machine - Google Patents

Description

117601

The invention relates to a device according to the preamble of claim 1 in connection with a headbox of a paper or board machine.

The invention also relates to a method according to the preamble of claim 4 in connection with a headbox of a paper or board machine.

10

A so-called dilution headbox is known in the art, which refers to a headbox of a paper or board machine in which a dilution stream is mixed with a mass flow derived from the headbox manifolds to control the basis weight of the web. Dilution flow control uses a valve structure through which the proportion of the dilution flow is controlled and in which a plurality of valves are disposed in parallel along a cross section of a paper or board machine so that the desired flow through each valve can be adjusted. The medium used for the dilution flow is fiber-containing tap water or pure water derived from the wire section. U.S. Patent No. 5,545,293 discloses an exemplary embodiment of a so-called dilution-20 headbox.

In turn, U.S. Patent No. 5,800,678 discloses an application for use in connection with a headbox of a paper or board machine for the dilution flow control of a * * * m * 0! * V constant valve consisting of a valve housing , the spindle and its flow • · channel, which can be rotated to different control positions to control the dilution 0Φ flow from the valve. The other end of the flow channel and the flow port of the valve housing or the like are aligned with each other.

Ml *. ···, the position of the other end opening of the channel in the cage to the valve housing or the like stream. adjustable with respect to the bore opening by rotating the spindle. The valve also includes an intermediate • · «•« #!.! 30 to prevent flow leakage between the • · * "walls of the valve stem and the valve body cavity.

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0 0 0 0 00 0 0 117601

Within the prior art dilution valves used in the headboxes of paper or board machines, depending on the speed of the machine, the overpressure is affected up to 7 to 8 bar, causing the valve control force 5 to increase and thereby increasing the size and cost of the actuator. In addition, the sliding surfaces of the valve are subjected to high stress during operation, which can cause problems with valve wear and possible jamming.

10 As is known in the art, valves are positioned side by side along the machine, even at intervals of less than 60 mm, whereby the increase in actuator size also causes difficulties in positioning the actuator. Because there are several valves, up to 150 per machine, their reliability is very important for the machine's running safety, as individual valves cannot be replaced during operation and, on the other hand, poor functioning or non-functioning 15 valves can cause quality problems in paper or board.

As is known in the art, problems with the use of dilution valves have also been caused by the corrosive properties of the particles contained in the dilution water as well as the possible situations where dirt may accumulate inside the valve.

• · · • · · »* ·· '1; It is an object of the invention to provide an apparatus and method in which prior art

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“1! The disadvantages and problems associated with known dilution valves have been eliminated and at least minimized.

* ·· 25 * 1

It is still an object of the invention to provide a cost-effective and narrower dilution zone known in the art. low dilution valve with low control force.

• »• · · 1 1 · · · i · 30 11« • · • · · · · · · 3 376601

A further object of the invention is to provide a rigid arrangement in which corrosion problems are eliminated or at least minimized.

In order to achieve the foregoing and further objects, the apparatus of the invention in connection with the headbox of a paper or board machine is essentially characterized by what is stated in the characterizing part of claim 1.

The method according to the invention, in turn, is essentially characterized by what is disclosed in the characterizing part of claim 4.

According to the invention, the device in connection with a headbox of a paper or board machine comprises balancing means tracked in connection with a dilution valve, based on the balancing force exerted by the medium introduced into the valve, preferably compressed air, acting on the dilution flow. According to the invention, a pressurized fluid, e.g. a gas or a liquid, most preferably compressed air, is used to provide a balancing force, i.e. a counter-force. Thus, for example, water, oil or other similar fluid may be used as a medium instead of compressed air. The magnitude of the balancing force, i.e. the back pressure, is preferably equal to or slightly less than the dilution water pressure used.

• · · ·· "The balancing means comprise an actuator that is tracked along the valve to provide • ♦ c“ 1 2 3Γ balancing force.

* 1 · 1 «· • ♦ · · # ♦ · '· * ♦ ···.

According to a further advantageous feature of the invention, the balancing means are manually operated. · · Negative control elements, which allow the balancing force to be automatically adjusted so that the internal back pressure of the valve is adjusted by>> 1 ·.

··· «. ···, according to Iin internal pressure and the force remains constant regardless of the valve stem spindle •, ·, or the dilution flow control.

• · »* ♦ 1 · 1 30 • · • • • • ♦ · · · 2 • · · 3 · ♦ · • ·: 4 117601

According to the invention, the dilution valve is preferably constructed so that it has no dirt collection areas, thereby improving the reliability of the valve and reducing corrosion problems, and particularly when using compressed air to provide corrosion resistance to acid resistant material used in valve structures.

According to the invention, the balancing means are arranged so that the back pressure acts behind the means for preventing flow leakage.

According to the invention, the back pressure exerted by the balancing means reduces the function of the valve, improves sealing and ventilates the narrow gap between the valve plug and body, thereby improving corrosion resistance. In addition, the balancing means allow for a smaller actuator size to provide pressure, whereby the dilution valves can be placed in a smaller cross-section of the machine compared to prior art solutions, whereby narrower dilution zones can be used.

The device and method according to the invention are applicable in connection with so-called linear and circular valves.

20 • • e ♦ · · **. The invention is applicable to both new headboxes and modernizable headboxes.

* ·· 1 for use with sizes.

The invention will now be described in more detail with reference to the figures in the accompanying drawing, which, however, are not to be construed in any way as limiting the invention.

• · • · «m · ·

Ml ·, · 1 ·. Figure 1 schematically shows a headbox of a paper machine in a longitudinal direction. in cross section.

• · · · · 30 «· · v • f • · • · ♦ • 9« ♦ · • ♦ · · • 9 • ·· • ♦ 5:: 117601

Figure 2 is a schematic representation of area X of Figure 1 on an enlarged scale.

Figure 3 is a schematic cross-sectional view of an embodiment 5 of the device according to the invention.

Figure 4 is a schematic cross-sectional view of another embodiment of an apparatus according to the invention.

The embodiment of Fig. 1 of the known headbox 10 comprises a manifold 11 from which the mass flow M is led through the inlet plate 12 to the bollard 13. Following the inlet plate 12 is a manifold 19. Both the inlet plate 12 and the manifold 19 comprise vertical and horizontal channels 21, 22 to each other via branch channels (not shown). The channels 22 of the distributor plate 19 are tapered in the direction of the flow 15 and connect to the channels 23 at their respective positions in the bellows 13. valves 20 for adjusting the basis weight of the web. Each valve appears to be a dilution flow L through a tapered conduit 22 in the distributor plate 19.

Il · *** / The mass flow M + L is further directed to the intermediate chamber 14 which opens from above ··· **** to the equalization chamber 15. From the intermediate chamber 14, the mass flow M + L is directed to the turbulence generator 16 and further to the headbox lip channel 17 and from the lip channel 17 • · · ♦ ♦ · I'V for forming wire H. As shown in Figure 1, the diluent flow divider logger 18 and the mass flow divider 11 overlap such that these dilution! fluid and mass distribution spaces are separated by a common partition. The partition wall is • connected, for example, by welding to the inlet plate 12.

«· · • · · · · · · · · · · · ·

Figure 2 illustrates on an enlarged scale the introduction of diluent into the headbox • 1 · V 30 via valve 20 in the headbox of Figure 1. In the figure • ·

7 2 shows an area X of FIG. 1 on an enlarged scale. Dilution flow L

• · • · · • · · · - ?. Through the adjusting valve 20, i.e. the dilution valve 20, the amount of dilution liquid L from the manifold 18 is controlled. The dilution fluid flow L from the manifold 18 comes through the passage of the inlet plate 12 to the valve 20. The spindle 24 of the valve 20 is rotated by the control motor 28. Thus, the position 5 of the flow port 25 is aligned with the flow port outlet of the valve housing 26. When the flow L is at its maximum, the outlet opening 25 of the flow channel 25 of the mandrel 24 is at the outlet of the valve housing 26.

In accordance with the invention, the diluent valve 20 is provided with a balancing means 10 comprising a supply of a medium, for example compressed air, which produces a balancing force, whereby the pressure of the medium produces a balancing force, i.e., a Instead of pressurized air, another suitable pressurized fluid, for example gas or liquid, may be used as the medium. Preferably, the equilibrium means Z provide the same pressure as or slightly lower than that of the dilution water used. The balancing means Z comprise an actuator arranged in connection with the supply of compressed air to provide the necessary balancing force, i.e. back pressure. Preferably, the balancing means Z also comprises control elements which allow the balancing force to be automatically adjusted to the appropriate pressure within the valve 20, regardless of the position of the valve stem 24, «« 1 · · · · *. The back pressure acts on the valve stem 20 behind the valve stem 24, reducing the operation of the ·· * ··· valve 20.

Fig. 3 is a schematic cross-sectional view of one embodiment of a diluent flow control valve 20 according to the invention, i.e. diluent 4; f • a to valve 20. The valves 20 mounted at different widths of the headbox are adapted to the weather. 1 and 2 above, 4a a. · · ·. described. The valve 20 comprises a valve housing 26 within which the spindle cavity has a · · spindle 24. The valve housing 26 may be a separate body structure or be part of the • · · 30 manifold. Valve 20 may be a separate unit which may be fitted completely apart from the headbox, or may be a unit shown in the figures, which may be: ii * * ♦ ♦ ii; · 7 117601 thus fits in with the manifold 19 so that the valve body 26 of the valve can be inserted in the opening made with the manifold 19. The mandrel 24 comprises a channel 25 which opens at both the end of the valve mandrel 24 and the side surface of the cylindrical valve mandrel 24. The channel 25 comprises end openings; a first end port, or stream inlet 5, and a second end port, or stream outlet. Preferably, the flow passage 25 has a cross section. The channel 25 comprises a curved, smooth bend T, by means of which the dilution flow L is smoothly conducted from the dilution fluid inlet to its outlet at the side surface of the cylindrical mandrel. The valve stem 24 is pivotable in the valve housing 26 about the longitudinal and central axis (d-axis) of the stem 24 to various adjustment positions by a motor 28 (Figs. 1 and 2), preferably an electric motor which may be a stepper motor. The electric motor 28 is connected either directly or via a gear to the shaft of the spindle 24. By rotating the spindle 24, the outlet of the flow passage 25 of the spindle 24 is obtained in different positions relative to the outlet of the valve housing 26. Hereby the throttling of the flow L is obtained. The other end opening of the flow passage 25 and the flow opening of the valve 15 housing or the like are aligned regardless of the pivot position of the spindle 24. Their position relative to each other does not change during the adjustment. An annular gasket 29 is provided between the mandrel 24 of the mandrel 24 and the mandrel cavity of the valve body 26.

In accordance with the invention, a means Z for balancing 20 is provided in connection with the dilution valve 20, which provides for balancing the pressure exerted by the dilution flow L acting within the valve 20. The equilibration means Z comprise the supply of intermediate medium. Compressed air produces an equilibrium force of the dilution flow L on the pressure ··· * 1 1 1. Compressed air or the like medium is supplied through duct 35 to the back of valve stem 24 of valve I 1 · 2 · 2. An actuator (not shown · · · * !!. 1 25) is provided in connection with the supply of compressed air to provide the necessary back pressure. Preferably, the balancing means Z is provided with adjusting means (not shown) which enable the balancing butter. Automatically adjusting the 1 hour to suit the pressure within the valve 20, regardless of the position of the valve stem 24.

Figure 4 schematically illustrates another embodiment of a device according to the invention, which is a so-called linear motion application in which the dilution flow is adjusted. Implemented by a linearly movable spindle 24, the position of the spindle 24 defining the amount of dilution flow L to be discharged through the conduit 46. Through the actuator 30, pressure of the dilution water is obtained. The dilution flow L is led from channel 35 through valve 20 to the mass flow. This embodiment of the invention also includes balancing means Z arranged in connection with valve 20, which comprises a space 38 behind the linear piston 37 of valve 20, from which the back pressure to the dilution flow pressure is supplied from the pressurized fluid supply via duct 35, thereby reducing the need for actuator 30. As shown in Fig. 4, the valve movement is linear, unlike in the embodiments described above with reference to Figures 2 and 3. In principle and otherwise, this embodiment of the invention is as described above, and like reference numerals are used for like parts.

The invention has been described above with reference only to some preferred embodiments thereof, the details of which, however, are not to be construed as being limited in any way.

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Claims (6)

An apparatus for an inlet carriage in a paper or cardboard machine, the device comprising a valve (20) for controlling a dilution flow (L) conducted into the mass flow (M) of the inlet carriage (10) or a dilution valve (20). ), which dilution valve (20) comprises a channel (25) for conducting the dilution flow (L) through the valve (20), a valve stem (24) and a valve housing; (26), and a function device (28,30) for controlling the pressure of the dilution flow (L) inside the valve (20), characterized in that balancing means (Z) for the pressure are arranged in conjunction with the dilution valve (20). of the dilution flow (L) for providing a balancing force to be effected behind the valve spindle (24) in the valve (20), that the balancing means (Z) comprise supply of a pressurized medium and a channel (35) for conducting the medium behind the valve spindle (24) and a pressurizing device of the medium. 2. Device according to claim 1, characterized in that the balancing means (Z) further comprise control means for controlling the balancing force which is provided with the pressurized medium. *: 1 20 * 1 · · Device according to claim 1 or 2, characterized in that the pressurized • ·! the medium is compressed air. • · * ·· ··· • ♦ · · • · · »· * · ..1 A method of an inlet carriage in a paper or cardboard machine, which further comprises conducting a dilution flow (L) into the pulp flow and regulating the dilution flow (L) by molding. 1, a valve spindle (24) in the valve (20), characterized in that, in the method, a counterpressure to the pressure of the dilution flow (L) acting in the valve (20) ... · is achieved by means of balancing means (Z), that the back pressure is achieved · 1 · 1: 30 with a pressurized medium, which is introduced behind the valve stem (24) in the valve (20). • 1 • ΐ · 117601 12 5. A method according to claim 4, characterized in that in the method of the balancing force effected by the pressurized medium is controlled according to the pressure which the internal dilution flow (L) in the valve (20) gives rise to. 5 6. A method according to claim 5, characterized in that the balancing force is regulated in such a way that the force is constantly poured in regardless of the control of the dilution flow (L). 1 ··· «1 · • · · • · · · t 1 1 * • · Φ · •» · • · · ···· '. • Φ • · · • f · '.' 1 • · · »» * ·· * 1 • · ··· '' 'm • · · • · · * · · ·· 1' • · ··· • · · * 1 · • · · · · · · · · · · · · · · · 1 · · · · · · · · ·