JPH0359725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary filtration machine, particularly a rotary filtration machine for separating fibers from a fiber suspension, which comprises a plurality of filtration disks each consisting of a collection of filtration elements. The disks are substantially parallel and axially spaced and mounted on a horizontal drum supported on bearings and rotated by a motor within a container of the fiber suspension to be subjected to the separation operation. has been
Each over-element consists of a hollow housing with walls made of fabric, which communicates with the axial discharge pipe of the drum via a liquid outlet located closest to its center of rotation. The part corresponding to the cylindrical surface of this drum is made up of axial tubes arranged in a framework structure, and these axial tubes are actually the discharge tubes that communicate with the over-element. has a cake collecting hopper inserted into the drum from one open end of the drum, the hopper opening upwards and extending over the entire number of cake discs attached to the drum, each of the cake collection hoppers being The internal pressure of the drum is individually maintained at a lower pressure than the pressure outside it, at least in one section of one revolution of the drum.

Such a mechanism is covered by the Swedish patent no.
It is known from specification No. 7406315-7. The rotary machine known from this patent is an improvement compared to previously known designs. By locating the cake collecting hopper in the drum to receive the separated fiber mass, the liquid level in the vessel of the machine can be raised higher than was previously possible, thus reducing the surface of the machine. The advantage was that it was more accessible. Because the cake collecting hopper is located within the drum rather than between the overdiscs, its moving parts operate completely free from wear, thus extending its service life.

Furthermore, the distance between overlapping disks can be shortened. Thus, for a given capacity superdisk, its space requirements are significantly reduced. However, this type of rotating machine has a few drawbacks. The required overarea for a given separation power was still relatively large.

Furthermore, due to the need to have a sufficiently large opening in the center of the rotating drum for passage to the collecting hopper of the separated fiber cake, the axial discharge pipe in the drum is substantially rectangular in cross section and its length It was necessary to create a design in which the directional symmetry axis overlapped with the radius of the rotating drum. Because the discharge pipe is subject to varying loads, such a design requires a relatively thick wall thickness, resulting in a high weight. Also, the production cost is very high.

It is an object of the present invention to provide a rotary turbulator of the type mentioned at the outset, but with a substantially greater capacity per unit sectional area, better safety of operation, and a higher solids content in the separated fibers. , and also to provide a product that is lighter in weight and cheaper to manufacture.

Such a disc-type turbulator according to the invention is characterized in that said axial tube has a diameter of at least 2 when viewed in cross section.
It is characterized by the fact that the books are arranged in groups. With such a design, the capacity can be increased because, for a given overarea, the opening leading to the center of the overmachine is larger, ie the separated fibers can pass through more freely. Thus, such a disk type filter machine can be operated at substantially higher rotational speeds than previously possible. In fact, you can double the speed.
That means a 40% increase in capacity. In short, the size of the above opening is determined by the interval between the axial discharge pipes.
This results in possible rotational speeds.

According to the invention, a disk-type turbulator of the type mentioned at the outset is made substantially cheaper, since standard cross-sections for the axial discharge tube, i.e. circular cross-sections, can be used in suitable embodiments. Can be manufactured. Thus, the weight of this disc-type filter is substantially reduced compared to conventional designs.

Other cross-sectional shapes of the axial tubes can also be used in the application of the invention, for example square cross-sections. In this case, the tubes have the advantage of being combined in a suitable manner, thereby making it possible to further enlarge the openings between the groups of axial discharge tubes.

The tubes can also be made in one piece with a common septum and a non-square shape in cross section. This structure is particularly suitable in one embodiment in which the tubes are arranged in cross-section at substantially the same distance from the center of the drum.

In one embodiment of the disk-type overmachine according to the invention, one over-element is arranged in one axial tube which is behind this over-element or at its rear end when seen in the direction of rotation. while the over-elements following it communicate with other axial tubes grouped with the tubes mentioned above.

In one suitable embodiment of the disk-type turbine according to the invention, the tubes in the group have their axes of symmetry lying on a radius passing through the center of the rotating drum in cross-section. They are arranged at different distances from the center of rotation, or in the vicinity of one radius.

In one suitable variation of this embodiment,
The tubes closer to the center of the rotating drum are placed further along the circumference in the direction of rotation of the rotating drum than the tubes farther from the center. This embodiment allows for a suitable passage of the fiber cake separated from the over-element to the collection hopper. To make this path easier to navigate, guide plates can be arranged on the front and rear sides of the tube in the axial direction, but on the front and rear sides when viewed in the direction of rotation of the rotating drum. It would also be a good idea to make the tube and guide plate as one unit.

It is often appropriate to arrange this guide plate in such a way that it extends radially beyond the axial tube, preferably as far as occupying part of the span of the over-element.

There are various ways to facilitate cake removal from the surface of the over-element, depending on the type of fibers present. Traditionally, the fiber cake has been removed by blowing high pressure or compressed air in the so-called cake removal zone, that is, in the zone above the cake collection hopper, where there is no longer a negative pressure inside the cake (adhesion surface). It was getting worse. However, some fibers are easily dehydrated and produce a thick pulp cake on top of the fibers. These pulp cakes can be difficult to remove and require special equipment. In a few suitable embodiments of the apparatus according to the invention, in the decaking zone a certain amount of positive pressure is provided on a portion of the inside of the dehydrated fiber cake, which initiates the decaking of the fibers. , after which the device can be designed so that gravity completes the disengagement. Furthermore, in order to facilitate disengagement, the over-element can be tilted towards the outside when viewed in longitudinal section, at least in a part of the circumference. Connecting pipes can be arranged on the circumference of the over-element in such a way that they open on the one hand into the underside of the cake and on the other hand can be connected to pressurized liquid or gas lines. The opening of the connecting tube in the side surface must be designed in such a way that the fiber cake can form a bridge thereon. That is, the openings must be narrow and long.

It is particularly suitable to arrange the connecting pipe in such a way that it connects to a stationary nozzle for supplying pressure or gas or liquid in one section of one revolution of the rotating drum, i.e. in the cake-dropping zone. be. The use of such a device to aid in fiber decaking reduces the amount of water required, if water is used, and thus increases the solids content of the separated fiber mass. When compressed gas is used, which is usually compressed air, the gas flow requirements are reduced and costs are reduced.

The present invention will be explained in more detail below with reference to the drawings.

In FIG. 1, 1 is a container for a fiber suspension, and 2 is a superrotor whose axis is horizontal, a part of which enters into the container 1 and rotates. The superrotor 2 has several annular superdiscs 3 mounted on a substantially parallel horizontal drum 4, which is connected to a drive motor. The flow disc 3 consists of several individual flow elements 5, each of which consists of a hollow housing with walls of cloth, through which an axial liquid outlet is located at the end closest to the center of rotation. It is connected to the discharge pipe 6. In FIG. 4, the over-element 5 ¹ communicates with the axial discharge pipe 6 ⁴ via the branch pipe 7 1 , and the over-element 5 ² communicates with the axial discharge pipe 6 ⁴ via the branch pipe 7 ² .
³ shows the details of the communication.

In this way, the drum 4 has an axial pipe 6 and a branch pipe 7.
It consists of Instead of using these branch pipes, it is also possible to incorporate (axial) pipes into the over-element, as shown in FIGS. 15, 17 and 18. The details of the coupling with the drive motor are not shown, but are of well known technology.

A collection hopper 8 is inserted into the drum 4 from one open end thereof, and its upwardly directed opening 9 extends over the entire number of over-discs mounted on the drum. Overrotor 2 is the third
In the figure, the fiber suspension is rotated in the direction indicated by arrow 10, and the liquid level of the fiber suspension in container 1 is at 11.
In order to operate the rotating turbulator according to the invention in an optimal state, a negative pressure exists inside the turbidity element during one section of one rotation, and this pressure acts on the outside of the turbidity element 5 below the liquid level. It must be able to add to the hydraulic pressure.

This negative pressure can be obtained by means of a vacuum pump or by designing the discharge pipe 13 as a so-called siphon pipe.

When the over-element 5 rotates and reaches the cake dropping zone, the communication between the vacuum source and the inside of the over-element 5 is established.
cut off by a look device 12;
The interior of the over-element is instead communicated with the atmosphere to relieve the vacuum and allow the fiber cake to break away.

A conveying screw 14 that is supported by bearings and rotates is installed in the collecting hopper 8 for the purpose of taking out the lumps of fibers that fall into the hopper 8.

As can be seen particularly clearly in FIGS. 4, 5 and 8, the axial discharge pipes 6 are arranged in groups of at least two when viewed in cross section. has been done. In the embodiment of FIGS. 4 and 5, the central axes of each of these tubes lie in the vicinity of one radius through the center of the rotating drum 4, but at different distances from the drum center. In the case of FIG. 8, the tubes are at substantially equal radial distances from the drum center.

In the embodiment shown in FIGS. 4 and 5, the tubes closer to the center of the rotating drum 4 (e.g. 6 ² and 6 ⁴ ) are the tubes farther from the center (6 ¹ and 6 ³ in FIG. 4). It is placed further along the circumference in the direction of rotation of the rotating drum. In FIGS. 4 and 5 the tubes are of circular cross-section, whereas in FIGS. 6 and 7 they are square.

In order to facilitate the passage of the mass of fibers separated from the overlay elements, in the case of FIG. ⁵ , tubes 65, ⁶⁶ , ^{67 are}
And 1 glide plate at 6 ⁸ , 6 ⁹ , 6 ¹⁰
5, 16 and 17, 18, respectively. In the case of FIG. 4, corresponding guide plates 15 ¹ , 16 1 and 17 ¹ , 18 ₁ are provided on the tubes 6 ¹ , 6 ² and 6 ³ , ₆ ⁴ , respectively.
It is often sufficient to provide such a guide plate only on the front side of the tube, viewed in the direction of rotation. If the tube is rectangular as shown in Figures 6 and 7, the walls of the tube will form a large part of the guide plate, and the guide plate can be extended radially beyond the axial tube to form a mass of fibers. To create a snag-free passageway for the pipes, it is only necessary to add small sections, indicated at 19, 20 and 21, 22 in these figures. Guide plates 15, 16, 17 in FIG.
18 extends further radially, as seen in the figure, and occupies up to a part of the radial span of the over-element 5, thereby ensuring good passage of the fiber mass. .

In the design shown in FIG. 8, tubes 6 ¹⁶ , 6 ¹⁷ and 1
6 ¹⁸ , 16 ¹⁹ are approximately equal radial distances from the drum center. The tubes still share one septum and are united. Figure 10 and 1
Figure 1 shows another example of a black shape of the tubes, but in these cases too the tubes are at approximately equal radial distances from the center of the drum.

One further modification is shown in FIG. This modification differs from the one described above because in every other over-element, the axial tubes with which they communicate are located at the front of the over-element when viewed in the direction of rotation of the drum on a cross-section. , or located at the front end of it. Other over-elements communicate with axial tubes located behind or at the rear end of the over-element when viewed in the same plane and in the same direction as above. These two types of axial tubes are arranged in groups of two.

For best performance, the wall of the rotationally trailing edge of the over-element should be connected to the axial tube while the over-element is out of communication with the vacuum and in communication with the atmosphere. must lean towards. That is, as the rotation progresses, the tilt must change to horizontal (from reverse tilt).

What is schematically shown in FIG. 18 is a combination of the main embodiment of FIG. 4 and the embodiment of FIG. 15. As is clear from the figure, three tubes in the axial direction are in one group, and one over-element ¹⁸¹ of the three tubes is located in front of the over-element or at its front end when viewed in the rotational direction. They are connected along a certain axis. Other over-elements communicate with axial tubes located after or at the rear end of the over-element. These three types of axial tubes are arranged in groups of three. Although in the figures the tubes are at different radial distances from the center of rotation, it is also possible to arrange the tubes circumferentially side by side at equal radial distances from the center of rotation.

In FIG. 16, the path of the liquid from the over-element is shown, i.e. via an axial tube to the liquid outlet and, although not shown, to a locking mechanism or other liquid drainage device according to FIGS. 1-3. Schematically shows the route leading to.

FIG. 17 schematically shows the liquid path in the case of the design shown in FIG. 15.

Although the liquid path is shown in a similar manner in FIG. 18, this is a combination of the embodiments of FIGS. 16 and 17.

In the case of FIG. 16, it is clear that the discharge tubes corresponding to the axial tubes of each over-element are offset by the same angle to the rear, measured from the center of gravity of the over-surface.

This means that liquid can be completely drained from the over-element, almost irrespective of its shape.

In the embodiments of FIGS. 15 and 17, on the contrary, the over-element must be designed such that the slope of the wall of the trailing edge is such that there are no pockets that cannot be drained. This is especially necessary once the over-element has been disconnected from the vacuum source.

Certain easily dehydrated fiber suspensions are
It produces a very thick pulp cake that is not easily separated from the overlying elements. 1st
In Figures 2, 13, and 14, over element 5
A few devices are shown at the circumference of the device to facilitate the removal of the fiber mass from the overlay element.
In the embodiment shown in FIG.
The walls 23 on both sides are connected by a connecting intermediate wall 24, in which the walls 23 extend a little further outward than the intermediate wall 24. Nozzle device 25
is arranged towards the inner surface of the extension of said wall 23 in the section of one revolution of the rotary drum 4 in which the mass of fibers is to be dropped, i.e. in the cake-dropping zone, through this nozzle. It is arranged in such a way that by supplying gas or liquid, a mass of fibers breaks away at its outer periphery and draws on other parts of the fiber cake.

It is also possible to provide a tube arrangement 26 in place of the nozzle described above, which can be connected with connecting pipes 27, 28 opening into the side surfaces 29 of the walls on both sides of the cover element, in a similar arrangement to that of the nozzle described above. Figure 13). In another embodiment, it is connected with connecting tubes 31, 32 opening into the surface, but in this case an outwardly curved wall 33 (in longitudinal section), which is joined at the circumference by a connecting intermediate wall 34. Two branched pipe arrangements 30 are provided so that the pipes can be separated. The advantage of outwardly curved walls is that such a design makes it easier to release the fiber cake (FIG. 14).

FIG. 5 shows an embodiment in which the device of FIG. 12, 13 or 14 is incorporated into a special element 36 which communicates with the interior of the over-element.

The function of this rotating machine will become clear from the above explanation. The fiber suspension is fed through the inlet 35 and clumps of fibers accumulate on the surface of the filter element while they are submerged below the liquid level 11 in the container 1. The liquid is continuously discharged through outlet pipe 13. In the upper half, i.e. in the cake drop zone, the negative pressure (in the excess element) disappears and the fiber cake is removed as the case may be.
The dehydrated fiber mass is assisted by the device shown in FIG.
and is ejected.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a rotating machine according to the present invention, which is a cross-section taken at - in FIG.
Figure 2 is an expanded view of the cross section at - in Figure 1, Figure 3 is a cross-sectional view at - in Figure 1, and Figure 4 is a cross-sectional view at - in Figure 1, showing a part of Figure 3. It is shown enlarged. FIG. 5 is a sectional view of another embodiment of the part shown in FIG. 4 in the filter machine; FIGS. 6 and 7 are axial discharges with guide plates (in FIGS. 4 and 5); FIG. FIG. 8 is a cross-sectional view of an alternative embodiment of the section shown in FIG. 4 in the machine; FIG. 9 is a cross-sectional view at - of FIG. 10 and 11 are cross-sectional views of alternative embodiments of axial discharge pipes with a common bulkhead; FIGS. 12 and 13;
and FIG. 14 are cross-sectional views of different embodiments for removing the fiber cake, FIG. 15 is a cross-sectional view of a further embodiment of the part shown in FIG. 4 in the filter; Figures 16, 17 and 18 are schematic partial cross-sectional views of a portion of the filter, including the filter element, the axial tube and the liquid outlet. 1... Container, 2... Super rotor, 3... Super disc, 4... Rotating drum, 5... Super element,
6... Axial pipe for liquid discharge, 7... Branch pipe for liquid discharge, 8... Cake collecting hopper, 9... Opening of cake collecting hopper, 10... Excess rotor rotation direction, 11... Liquid in container Surface, 12... Vacuum lock mechanism, 13... Liquid discharge pipe (negative pressure), 14
...Conveyance screw, 15, 16, 17, 18...
...Cake falling guide plate (mounted on circular cross-section pipe), 1
9, 20, 21, 22... Cake fall guide plate (mounted on rectangular section pipe), 23... Overwall surface, 24...
... connecting intermediate wall of overwall, 25 ... nozzle device for cake separation, 26 ... pipe device for cake separation, 27,
28... Connecting pipe for cake removal, 29... Extended wall surface, 30... Connecting pipe for cake removal, 31, 32...
... Connecting pipe for cake removal, 33 ... Inclined portion of overwall surface, 35 ... Fiber suspension inlet, 36 ... Connection element (for cake removal), 37 ... Over element, 38 ...
... over-element, 39... common wall of the axial discharge pipe.

Claims (1)

[Scope of Claims] 1. A rotary filtration machine for separating fibers from a fiber suspension, which has a plurality of annular filtration disks in which filtration elements 5 are assembled, and these filtration disks are used for separation operations. mounted substantially parallel and axially spaced on one horizontal drum 4 which is rotatably supported on bearings within a container 1 containing the fiber suspension to be carried out. , each filtration element consists of a hollow housing with walls made of filtering material that discharges filtrate in the axial direction of the drum via a filtrate outlet located closest to the center of rotation of the housing. It communicates with an axial discharge pipe 6, which drum comprises a cylindrical side wall of the skeleton structure containing said axial discharge pipe and a collection extending over all filter discs to receive the material separated from the filter element. A rotary filter comprising a hopper 8 and means for keeping the internal pressure of each filter element individually at a lower pressure than the pressure outside it, at least in one section during one rotation of the drum, said shaft; A rotary filter characterized in that the directional tubes 6 are arranged in a plurality of groups of at least two adjacent tubes when viewed in cross section. 2 The symmetrical axes of the axial discharge pipes 6 in the group are on the same radius around the axis of the rotatable drum 4, or in the vicinity of the radius, and the distances from the center of the drum are different. A rotary filter according to claim 1. 3. The rotary filter according to claim 1 or 2, wherein the discharge pipe 6 in the axial direction has a circular cross section. 4. A patent claim in which the tubes 6 ² , 6 ⁴ that are closer to the axis of the drum 4 are placed further forward in the rotational direction of the drum than the tubes 6 ¹ , 6 ³ that are farther from the axis of the drum. The rotary filter according to any one of the ranges 1 to 3. 5. Rotary filter according to claim 1, in which all axial discharge pipes 6 in the same group are at substantially the same distance from the axis of the drum 4. 6 One filter element 37 communicates with an axial discharge pipe 6 ²⁴ at the rear or rear end of the filter element 37 in the direction of rotation of the drum 4, while the one filter element 37 in the direction of rotation of the drum 4 The filtration element 38 connected immediately after the filtration element 37 is the 1
Any one of claims 1 to 5, in which the axial discharge pipe 6 ²⁴ is connected to one filter element and the axial discharge pipe 6 ^{25 is connected to the same group of axial discharge pipes 6 25} .
The rotary filtration machine described in section. 7 Axial discharge pipes of each group 6 ¹⁶ , 6 ¹⁷ , 6 ²⁴ ,
^6. The rotary filter according to any one of claims 1, 2, 4, 5, and 6, each having a shape in which each of the filters shares at least one partition wall. 8. Any one of claims 1 to 7, wherein the guide plates 15 to 18 are provided at least at the tip of the axial discharge pipe 6 in the rotational direction of the rotary drum 4 and cover the front surface thereof. The rotary filter according to item 1. 9. The rotary filter according to claim 8, wherein the guide plates 15 to 18 extend radially outward a little further than the axial discharge pipe 6. 10. The rotary filter according to claim 9, wherein the guide plates 15 to 18 extend in the radial direction of the filter element 5 until they occupy at least a part of the filter element 5. 11. The rotary filter according to any one of claims 1 to 10, wherein the surface of the filter element 5 is curved outward at least in one radial portion 33 thereof. 12 The filtration element 5 has connecting pipes 27, 28, 31, and 32 at its circumference that are open to the filtration surface. Piping 2 that supplies gas
6, 34. The rotary filter according to any one of claims 1 to 11, which is connected to a rotary filter. 13. A patent claim in which the connecting pipes 27, 28, 31, 32 are arranged to be connected to stationary nozzles 26, 34 that supply liquid or gas under pressure in one section of one rotation of the rotating drum 4. The rotary filter according to item 12. 14. According to any one of claims 10 to 13, in which the pair of wall surfaces 23 of the filter elements extend radially further outward than the connecting wall 24 connecting them. Rotary filter machine as described.