阅读说明：本技术 盘式过滤器和操作盘式过滤器的方法 (Disc filter and method for operating a disc filter ) 是由 H·迪奥纳 于 2019-08-09 设计创作，主要内容包括：本文公开了用于使纤维悬浮液脱水的盘式过滤器。根据第一方面,该盘式过滤器包括这样的容器,该容器包括定位在容器的壁中的入口,入口将纤维悬浮液引入到该容器中。盘式过滤器还包括转子轴,该转子轴包括定位在轴平面中的旋转轴线,其中该轴平面是水平面。至少一个过滤元件可以联接至转子轴。至少一个喷射器可以定位在容器的壁中,该至少一个喷射器将次级液体流引入到容器中。该至少一个喷射器可以以相对于轴平面大于-44度且小于或等于+22度的喷射器仰角α-I定位在容器的壁中。(Herein disclosedDisc filters for dewatering a fibre suspension are disclosed. According to a first aspect, the disc filter comprises a vessel comprising an inlet positioned in a wall of the vessel, which inlet introduces the fibre suspension into the vessel. The disc filter further comprises a rotor shaft comprising an axis of rotation positioned in a shaft plane, wherein the shaft plane is a horizontal plane. At least one filter element may be coupled to the rotor shaft. At least one injector may be positioned in a wall of the vessel, the at least one injector introducing the secondary liquid stream into the vessel. The at least one injector may be at an injector elevation angle α greater than-44 degrees and less than or equal to +22 degrees relative to the axial plane I Positioned in a wall of the container.)

1. A disc filter for dewatering a fibre suspension, the disc filter comprising:

a vessel comprising an inlet positioned in a wall of the vessel, the inlet introducing a fiber suspension into the vessel;

a rotor shaft comprising an axis of rotation positioned in a shaft plane, wherein the shaft plane is a horizontal plane; and

at least one filter element coupled to the rotor shaft such that the at least one filter element rotates with the rotor shaft about the axis of rotation; and

at least one injector positioned in a wall of the vessel, the at least one injector introducing a secondary liquid stream into the vessel, wherein:

the at least one injector is at an injector elevation angle a greater than-44 degrees and less than or equal to +22 degrees relative to the axial plane_IPositioned in a wall of the container; and

the main flow vector of the at least one ejector is orthogonal to the axis of rotation.

2. A disc filter according to claim 1,

a main component of the angular velocity vector ω of the at least one disc filter element is positively vertical near the at least one ejector; and

the main component of the angular velocity vector co of the at least one disc filter element is in the negative vertical direction near the inlet.

3. A disc filter according to claim 1, characterised in that the injector elevation angle α_I0 degrees relative to the axial plane.

4. A disc filter according to claim 1, characterised in that the injector elevation angle α_ILess than 0 degrees and greater than or equal to-44 degrees relative to the axial plane, or greater than 0 degrees and less than or equal to +22 degrees relative to the axial plane.

5. A disc filter according to claim 1, characterised in that the injector elevation angle α_IGreater than or equal to-15 degrees and less than or equal to +15 degrees relative to the axial plane.

6. A disc filter according to claim 1, characterised in that the injector elevation angle α_IGreater than or equal to-10 degrees and less than or equal to +10 degrees relative to the axial plane.

7. A disc filter according to claim 1, characterised in that the main flow vector of the at least one injector intersects the axis of rotation.

8. A disc filter according to claim 1, wherein the secondary liquid flow from the at least one ejector diverges vertically along the primary flow vector.

9. The disc filter of claim 1, wherein the outlet of the at least one injector includes a major axis and a minor axis, wherein the major axis has a length greater than a length of the minor axis.

10. A disc filter according to claim 9, characterised in that the width of the outlet varies along the main axis.

11. A disc filter according to claim 9, characterised in that the outlet has a dog-bone shaped cross-section.

12. A disc filter according to claim 1, wherein the outlet of the at least one injector is disposed between the outer radius of the at least one filter element and the wall of the container.

13. A disc filter according to claim 1, characterised in that the outlet of the at least one injector is arranged between the outer radius of the at least one filter element and the rotor shaft.

14. A disc filter according to claim 1 wherein the at least one filter element comprises a pair of adjacent filter elements and the at least one injector is positioned in a space between the pair of adjacent filter elements.

15. A disc filter according to claim 1, characterised in that the at least one ejector is positioned below the filling level of the fibre suspension in the container.

16. A disc filter according to claim 1, wherein the at least one injector is coupled to a supply manifold by an injector valve.

17. A disc filter according to claim 16 wherein the injector valve is communicatively coupled to a control system.

18. A disc filter according to claim 16, wherein the at least one injector is coupled to the injector valve by a flow meter.

19. A disc filter according to claim 18 wherein the flow meter and the injector valve are communicatively coupled to a control system.

20. A disc filter according to claim 1, wherein the at least one injector is coupled to the supply manifold by a flow meter.

21. A disc filter according to claim 1, wherein the secondary liquid flow from the at least one injector contacts the rotor shaft.

22. A disc filter according to claim 1, wherein the secondary liquid flow from the at least one injector does not contact the surface of the at least one filter element.

Technical Field

The present description relates generally to disc filters for separating cellulose fibers from a fiber suspension and, more particularly, to disc filters having an eductor for agitating the suspension during a filtration operation.

Technical Field

A typical disc filter used in the pulp and paper industry for dewatering a cellulosic fibre suspension generally comprises a plurality of disc-shaped filter elements mounted on a rotatable shaft such that the filter elements rotate with the rotor shaft within a vessel. The disc-shaped filter element is partially immersed in the suspension of cellulose fibres contained in the container. Each filter element may comprise several filter sectors distributed around the rotatable axis. Each filter sector is provided with an outer filter liner, such as a screen or the like, and internal flow channels which communicate with filtrate channels in the rotatable shaft.

The filter sectors move through the suspension in the vessel as the filter element rotates with the rotatable shaft. As the filter sector moves through the suspension, water is drawn from the suspension, through the filter liner on the filter sector and into the flow channels inside the filter sector, while fibrous material may be deposited as a fibrous mat on the outer surface of the filter liner. Subsequently, filtrate comprising said water flows from the flow channels in the filter sector to the filtrate channels in the rotor shaft and is discharged from the vessel through the filtrate outlet. As the filter element continues to rotate, the filter sector removes the suspension and passes through the nozzle, which directs a fluid jet toward the fiber mat, thereby loosening the fiber mat from the filter liner. The fibre material loosened from the filter lining falls into a receiver chute positioned alongside the filter lining on both sides of the respective filter element in a section of the vessel where the filter sector is rotated out of the suspension after moving through the suspension, i.e. at the side of the rotor shaft where the filter sector moves upwards during rotation of the filter element. At the bottom of the receiver chute, the fibrous material is picked up by a conveyor and proceeds to be further processed.

However, there is a need for alternative disc filters for separating cellulose fibres from a suspension.

Background

Disclosure of Invention

According to a first aspect, a disc filter for dewatering a fibre suspension comprises a vessel comprising an inlet positioned in a wall of the vessel, which inlet introduces the fibre suspension into the vessel. The disc filter further comprises a rotor shaft comprising the axis of rotation of the shaft in a shaft plane, wherein the shaft plane is a horizontal plane. The at least one filter element may be coupled to the rotor shaft such that the at least one filter element rotates with the rotor shaft about a rotational axis of the shaft. At least one injector may be positioned in a wall of the vessel, the at least one injector introducing the secondary liquid stream into the vessel. The liquid may be, for example, water or a fibre suspension. The at least one injector may be at an injector elevation angle α greater than-44 degrees and less than or equal to +22 degrees relative to the axial plane_IPositioned in a wall of the container. The main flow vector of the at least one ejector may be orthogonal to the axis of rotation of the shaft.

A second aspect (2) includes the disc filter of the first aspect, wherein: the main component of the angular velocity vector ω of the at least one disc filter element is positively vertical towards the at least one injector; and the main component of the angular velocity vector co of the at least one disc filter element is in the negative vertical direction near the inlet.

The third aspect (3) includes the disc filter of the first aspect (1) or the second aspect (2), wherein the injector elevation angle α_I0 degrees relative to the axial plane.

A fourth aspect (4) includes the disc filter of the first aspect (1) or the second aspect (2), wherein the injector elevation angle α_ILess than 0 degrees and greater than or equal to-44 degrees with respect to the axial plane, or greater than 0 degrees and less than or equal to +22 degrees with respect to the axial plane.

A fifth aspect (5) includes the disc filter of the first aspect (1) or the second aspect (2), wherein the injector elevation angle α_IGreater than or equal to-15 degrees and less than or equal to +15 degrees relative to the axial plane.

A sixth aspect (6) includes the disc filter of the first aspect (1) or the second aspect (2), wherein the injector elevation angle α_IGreater than or equal to-10 degrees and less than or equal to +10 degrees relative to the axial plane.

A seventh aspect (7) includes the disc filter of any one of the first to sixth aspects (1) to (6), wherein the main flow vector of the at least one ejector intersects the rotation axis.

An eighth aspect (8) includes the disc filter of any one of the first to seventh aspects (1) to (7), wherein the secondary liquid flow from the at least one ejector diverges vertically along the primary flow vector.

A ninth aspect (9) includes the disc filter of any one of the first to eighth aspects (1) to (8), wherein the outlet of the at least one ejector comprises a primary axis and a secondary axis, wherein the length of the primary axis is greater than the length of the secondary axis.

A tenth aspect (10) includes the disc filter of any one of the first to ninth aspects (1) to (9), wherein the width of the outlet varies along the main axis.

An eleventh aspect (11) includes the disc filter of any one of the first to tenth aspects (1) to (10), wherein the outlet has a dog-bone-shaped cross section.

A twelfth aspect (12) includes the disc filter of any of the first to eleventh aspects (11) to (11), wherein the outlet of the at least one ejector is disposed between the outer radius of the at least one filter element and the wall of the container.

A thirteenth aspect (13) includes the disc filter of any one of the first to eleventh aspects (11) to (11), wherein the outlet of the at least one ejector is disposed between the outer radius of the at least one filter element and the rotor shaft.

A fourteenth aspect (14) includes the disc filter of any one of the first to thirteenth aspects, wherein the at least one filter element includes a pair of adjacent filter elements, and the at least one injector is positioned in a space between the pair of adjacent filter elements.

A fifteenth aspect (15) includes the disc filter of any one of the first to sixth aspects (1) to (14), wherein at least one ejector is positioned below the filling level of the fibre suspension in the vessel.

A sixteenth aspect (16) includes the disc filter of any one of the first to fifteenth aspects (1) to (15), wherein the at least one ejector is coupled to the supply manifold through an ejector valve.

A seventeenth aspect (17) includes the disc filter of the sixteenth aspect (16), wherein the injector valve is communicatively coupled to the control system.

An eighteenth aspect (18) includes the disc filter of any one of the sixteenth (16) to seventeenth (17) aspects wherein the at least one ejector is coupled to the ejector valve by a flow meter.

A nineteenth aspect (19) includes the disc filter of the eighteenth aspect (18), wherein the flow meter and the injector valve are communicatively coupled to the control system.

A twentieth aspect (20) includes the disc filter of any one of the first to seventeenth aspects (1) to (17), wherein the at least one ejector is coupled to the supply manifold by a flow meter.

A twenty-first aspect (21) includes the disc filter of any one of the first to twentieth aspects (1) to (20), wherein the secondary liquid stream from the at least one injector contacts the rotor shaft.

A twenty-second aspect (22) includes the disc filter of any one of the first to twenty-second aspects (1) to (21), wherein the secondary liquid flow from the at least one injector does not contact a surface of the at least one filter element.

A twenty-third aspect (23) includes a disc filter having at least one ejector, as shown and described herein.

A twenty-fourth aspect (24) includes, a method of operating a disc filter as shown and described herein.

Additional features and advantages of the disc filter described herein will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing summary and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments described herein and together with the description serve to explain the principles and operations of the claimed subject matter.

Drawings

Fig. 1 schematically depicts an axial cross-section of a disc filter according to one or more embodiments shown and described herein;

FIG. 2 is a cross-section of the disc filter of FIG. 1 taken along line A-A including an ejector according to one or more embodiments shown and described herein;

fig. 3 schematically depicts a portion of a filter element and a receiver chute according to one or more embodiments shown and described herein;

fig. 4 schematically depicts a perspective view of a receiver chute and an adjacent inlet channel of a disc filter according to one or more embodiments shown and described herein;

FIG. 5 schematically depicts a top view of a disc filter including a plurality of injectors, according to one or more embodiments shown and described herein;

FIG. 6 schematically depicts a cross-section of the disc filter of FIG. 5 showing the positioning of the injector relative to the filter element and horizontal plane, in accordance with one or more embodiments shown and described herein;

FIG. 7 schematically depicts a sprayer positioned along a wall of a vessel according to one or more embodiments shown and described herein;

FIG. 8 schematically depicts a sprayer positioned along a wall of a vessel according to one or more embodiments shown and described herein;

FIG. 9 schematically depicts a flow cone of an ejector relative to a main flow vector of the ejector;

FIG. 10 schematically depicts an embodiment of an outlet of an injector;

FIG. 11 schematically depicts an embodiment of an outlet of an injector; and

FIG. 12 schematically depicts an embodiment of an injector.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

Reference will now be made in detail to embodiments of the disc filter described herein, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. One embodiment of a disc filter is schematically illustrated in fig. 1 and generally comprises a vessel comprising an inlet positioned in a wall of the vessel, the inlet introducing the fiber suspension into the vessel. The disc filter further comprises a rotor shaft comprising an axis of rotation positioned in a shaft plane, wherein the shaft plane is a horizontal plane. At least one filter element may be coupledTo the rotor shaft such that the at least one filter element rotates with the rotor shaft about the axis of rotation. At least one injector may be positioned in a wall of the vessel, the at least one injector introducing the secondary liquid stream into the vessel. The at least one injector may be at an injector elevation angle α greater than-44 degrees and less than or equal to +22 degrees relative to the axial plane_IPositioned in a wall of the container. The main flow vector of the at least one ejector may be orthogonal to the axis of rotation. Various embodiments of a disc filter and methods of operating the same will be described herein with particular reference to the accompanying drawings.

Ranges can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

Directional terms used herein, such as upper, lower, right, left, front, rear, top, bottom, are made with reference to the drawings as drawn only, and are not meant to imply absolute orientations.

Unless otherwise stated, it is in no way intended that any method described herein be construed as requiring that its steps be performed in a specific order, nor that it require any equipment, specific orientation. Thus, where a method claim does not recite exactly the order to be followed by the steps of the method, or where any apparatus claim does not recite exactly the order or direction of individual components, or where it is not otherwise stated in the claims or specification that the steps are to be limited to a specific order, or where a specific order or direction of components of an apparatus is not recited, no order or direction should be inferred, in any respect. This applies to any possible non-explicit basis for interpretation, including: logical considerations regarding step arrangement, operational flow, component order, or component orientation; obvious meanings derived from grammatical organization or numbering, and; the number or type of embodiments are described in the specification.

As used herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a" or "an" element includes aspects having two or more such elements, unless the context clearly dictates otherwise.

As used herein, the terms "free" and "freeness" refer to the tendency of a suspension to readily separate into its solid portion and its liquid portion. For example, cellulose fibers are more easily separated from a suspension having a "high freeness" than a suspension having a "low freeness".

Disc filters are used to separate cellulose fibres from a suspension of fibres in a fluid, such as water. Examples of disc filters are disclosed in: U.S. patent No. 9,238,188 entitled "Disc Filter" assigned to cadnt Black Clawson Inc (Kadant Black Clawson Inc.); U.S. Pat. No. 4,136,028, assigned to Rauma-Rapola Oy, entitled "Method for filtering fibrous Material by means of a disc Filter and disc Filter for carrying out the Method" (Method for filtering a fibrous Material by means of a disc Filter for performing the Method) "; and U.S. patent No. 6,258,282 entitled "Rotatable filter system for filtering flowing material" assigned to Kvaerner pulp equipment AB. Such a filter is effective for removing filtrate from a cellulose suspension having a high freeness. However, it has been found that the efficiency of such disc filters may decrease as the freeness of the suspension increases. In particular, it has been found that when separating fibres from a filtrate in a fibre suspension having a relatively high freeness, the fibre mat accumulated on the filter element may fall back into the fibre suspension as the filter element is rotated out of the suspension.

It has been determined that there are several factors that act in concert to cause the fiber mat to fall back into the fiber suspension. In particular, the relatively high freeness of the suspension allows for a greater rate of removal of filtrate from the fiber suspension than the rate of removal of fibers from the fiber suspension. This thickens the suspension. The thickened suspension acts as a mechanical scraper against the filter element as the filter element rotates through the suspension. The mechanical scraping action of the thickened suspension destroys the fiber mat at the surface of the filter element. The damage caused to the felt may appear as localized thinning (rarefaction) so that air can penetrate the felt and reduce the vacuum holding the felt on the filter element. As the suspension continues to thicken as more filtrate is removed from the suspension than the fibers, the thickened suspension may actually pull the fiber mat from the surface of the filter element as the filter element emerges from the suspension. This action reduces the efficiency of the disc filter.

In addition, the rapid removal of the filtrate from the suspension reduces the vacuum, which causes the fiber mat to adhere to the filter element. In particular, when filtrate is removed from the suspension at a much greater rate than the fibers, not enough filtrate remains in the suspension to compensate for the air penetration through the mat due to the mechanical scraping action of the thickened suspension. The reduction or loss of vacuum makes the fiber mat easier and prematurely removed from the filter element due to mechanical scraping of the thickened suspension. Thus, the reduction in the vacuum further reduces the efficiency of the disc filter.

The problem is cyclic in nature. The high freeness of the fibre suspension results in a greater rate of removal of filtrate from the suspension than the fibres, which in turn thickens the suspension. The thickened suspension causes the machine to scrape the fiber mat against the filter element, locally thin (or remove) the fiber mat, and pass air through the mat. The thinning of the felt allows more filtrate to pass through the felt and be removed from the suspension, thickening the suspension further and reducing the vacuum of the filter element. The thickened suspension and reduced vacuum of the filter element accelerate mat thinning and premature removal by mechanical scraping. The net result is an overall reduction in the efficiency of the disc filter.

Embodiments of a disc filter are disclosed herein that include an ejector for introducing a secondary liquid stream into the disc filter, thereby mitigating the effects described above. The liquid may include, for example, but is not limited to, a fiber suspension, a diluent such as water, or a combination thereof.

With particular reference to fig. 1 and 2, an embodiment of a disc filter 1 is schematically depicted. In this embodiment, the disc filter 1 generally comprises a vessel 2, which vessel 2 has an inlet 3 for introducing the cellulose fibre suspension into the vessel. The inlet 3 is connected to a conduit 4 through which the suspension is fed to the inlet 3 (such as by a main pump 180 as shown in figure 5). The container 2 comprises a lower part 2a and an upper part 2b connected to the lower part. The lower part 2a has a substantially U-shaped configuration and is closed at the top by an upper part 2b, which upper part 2b forms a hood above the lower part. The upper portion 2a and the lower portion 2b together generally define an interior space of the container. In the aspect shown, the interior space of the vessel is accessible through a hatch 5 in the upper part 2b of the vessel.

The disc filter further comprises a rotor unit 6 located in the inner space of the container 2. The rotor unit 6 comprises a rotor shaft 7 which is rotatably mounted to the container 2 and extends through the inner space of the container. In the example shown, the rotor shaft 7 is rotatably mounted to the lower part 2a of the container through a first bearing 8a arranged at a first end of the rotor shaft and a second bearing 8b arranged at the other end of the rotor shaft. The rotor shaft 7 extends through sealed openings in the end walls 9a, 9b of the container 2 and is rotated by means of a drive means 10, for example in the form of a drive motor, which drive means 10 is connected to the rotor shaft 7.

The rotor unit 6 further comprises a plurality of disc-shaped filter elements 11 carried by the rotor shaft 7 to rotate therewith while being partially immersed in the suspension received in the container 2. In the example shown, the rotor unit 6 is provided with four such filter elements 11. It should be understood, however, that the disc filter 1 may contain less than four filter elements, or alternatively more than four filter elements. Each filter element 11 extends at an angle to the longitudinal axis of the rotor shaft 7, preferably perpendicular to the longitudinal axis. In the embodiments described herein, the longitudinal axis coincides with the axis of rotation of the rotor unit 6. Furthermore, each filter element 11 extends in an annular configuration around the rotor shaft 7 and is divided into several filter sectors 12 distributed around the rotor shaft. The filter sectors 12 of a single filter element 11 are separated from each other by means of radially oriented partitions extending between opposite lateral surfaces of the filter element. As shown, the filter sectors are separated by radially oriented partitions. However, it should be understood that the dividers may be disposed in various positions other than radially, depending on cost considerations and other desired structural equivalent orientations. As shown, each filter element 11 is provided with an outer filter liner 13 (shown by the screen pattern in fig. 2) on its opposite lateral surfaces and an inner flow channel (not shown) communicating with a filtrate channel 14 in the rotor shaft 7 for conveying filtrate passing through the filter liner 13 to said filtrate channel 14.

It should be noted that various equivalent filter liner arrangements may be used in addition to the outer arrangement shown in the figures.

As shown in fig. 2, each individual filter sector 12 comprises a conduit section 15 for transferring filtrate, i.e. water filtered out of the suspension in the vessel 2, from the filter sector 12 in question into the associated filtrate channel 14 in the rotor shaft 7 through an opening provided on the envelope surface of the rotor shaft between the conduit section 15 and the filtrate channel 14.

The filtrate channels 14 extend in the axial direction of the rotor shaft 7. These filtrate channels 14 may be formed as sector-shaped spaces separated from each other by means of radially oriented partitions extending along the rotor shaft 7. The filtrate channels 14 are defined in an inward radial direction by a tubular core 17 of the rotor shaft 7. As shown in fig. 1, the tubular core 17 may have a varying diameter along the length of the rotor shaft 7, wherein the smallest diameter at the end of the tubular core is located at the end of the rotor shaft 7 where filtrate flows out of the rotor shaft 7 in the axial direction. In the example shown, two outlets 20, 21 are provided for the filtrate. The first outlet 20 is intended for prefiltering (turbid filtrate) and the other outlet 21 is intended for clarifying the filtrate. At least the clarified filtrate outlet 21 and possibly also the pre-filtrate outlet 20 may be connected to a drop tube 24 intended to establish a vacuum in the suction head 22. The suction head 22 communicates with the filtrate channel 14 in the rotor shaft 7 via a filtrate valve 23. When the rotor shaft 7 is rotated relative to the filtrate valve 23 and the suction head 22, the filtrate valve 23 will put the respective filtrate channel 14 in communication with either the pre-filtrate outlet 20 or the clarified filtrate outlet 21, depending on the prevailing rotational position of the rotor shaft 7.

As shown in fig. 2, the disc filter 1 further comprises at least one injector 110 extending through the wall of the container 2. As will be described in further detail herein, at least one eductor 110 is used to introduce a secondary liquid stream into the vessel 2 to promote dilution, agitation and mixing of the fiber suspension in the vessel, thereby reducing the consistency of the fiber suspension in the vessel and improving the efficiency of the disc filter 1. In embodiments, the secondary liquid stream may comprise water, a fiber suspension, or the like.

Still referring to fig. 2, the disc filter 1 may also be provided with a release member 25 for releasing fibrous material that has been filtered out of the suspension in the container 2 and deposited as a fibrous mat on the filter lining 13 of the respective filter element 11. In the example shown, the release members 25 comprise nozzles configured to: the fibrous material deposited on the filter lining of the respective filter element 11 is loosened from one filter sector 12 at a time in succession as the filter sectors of the filter element 11 rotate past the loosening members 25 arranged on opposite sides of the filter element 11 and into the range of the jet of water or any other suitable fluid emitted from these loosening members 25.

The disc filter 1 is further provided with cleaning members 26 for cleaning the filter lining 13 of the respective filter element 11 with rinsing liquid emitted therefrom. These cleaning members 26 comprise, for example, nozzles arranged on opposite sides of the respective filter element 11 and configured to emit jets of water or any other suitable rinsing liquid towards the filter lining 13 on opposite sides of the respective filter element. The cleaning members 26 are suitably mounted on pivotable bearings 27 configured to pivot back and forth to allow the cleaning members 26 to sweep across the filter lining 13 of the respective filter element 11 during rotation of the rotor unit 6. The carrier 27 is pivoted by a drive means 29, for example in the form of a drive motor. In the example shown, the release member 25 is connected to the carrier 27 such that the release member 25 pivots together with the cleaning member 26. However, the release member 25 may alternatively be fixed. The cleaning member 26 is located behind the release member 25 as seen in the direction of rotation of the filter element 11. Thus, the respective filter sector 12 of the filter element 11 will rotate past the release member 25 during rotation of the filter element, and then past the cleaning member 26.

The disc filter 1 comprises a plurality of receiver chutes 30, each provided at an upper end with a fiber mat inlet opening for receiving loose filter linings 13 of adjacent filter elements 11. Each filter element 11 has a first receiver chute 30 arranged alongside a portion of filter liner 13 on a first side of the filter element, and another receiver chute 30 arranged alongside a portion of filter liner 13 on the opposite side of the filter. One receiver chute 30 is positioned in the space between each pair of adjacent filter elements 11 and in the space between the respective outermost filter element 11 on the rotor shaft 7 and the adjacent end wall 9a, 9b of the container 2. In the embodiment shown in fig. 1-3, the receiver chute 30 is positioned in the part of the vessel 2 where the filter sector 12 is rotated downwards into the suspension from a position above the suspension during rotation of the rotor unit 6, i.e. the receiver chute 30 is positioned on such a side of the rotor shaft 7 that the filter sector 12 is rotated downwards after being released from the fibrous material and cleaned by the cleaning member 26. That is, the receiver chute is positioned at the side of the vessel 2 where the main component of the angular velocity of the filter element is in a downward vertical direction. However, in an alternative embodiment (not shown), the receiver chute 30 is positioned in a part of the vessel 2 where the filter sector 12 rotates out of the suspension from a position below the suspension during rotation of the rotor unit 6, i.e. the receiver chute 30 is positioned at the side of the rotor shaft 7 where the filter sector 12 rotates upwards. That is, in an alternative embodiment, the receiver chute is positioned at the side of the vessel 2 where the main component of the angular velocity of the filter element is in an upward vertical direction. The inlet opening at the upper end of each receiver chute 30 is positioned above a horizontal plane extending through the longitudinal axis of the rotor shaft 7 and the lateral edges of said inlet opening extend closely to the filter lining 13 of the adjacent filter elements 11 to effectively capture the fibre mat loosened from the filter sectors 12 of these filter elements. The side walls of each receiver chute 30 diverge at the upper part of the receiver chute near the entrance opening of the receiver chute, as shown in fig. 1. Furthermore, each receiver chute 30 is provided at its upper end with a portion 31 which is bent inwards into the area above the rotor shaft 7, as shown in fig. 2, to allow the inlet opening of the receiver chute to extend into this area.

The release member 25 and the cleaning member 26 are positioned above the receiver chute 30 on the side of the rotor shaft 7 where the filter sector 12 is rotated downwards towards the surface of the suspension in the vessel 2. The cleaning member 26 is configured to flush down the fibre mat loosened by the release member 25 into the receiver chute 30 by means of flushing liquid emitted from the cleaning member. The receiver chute 30 is configured to receive the fiber mat together with the rinsing liquid from the cleaning member 26, thereby allowing the fiber mat to be diluted to a desired solids content in the receiver chute 30 by means of the rinsing liquid. At a lower end 32, each receiver chute 30 is connected to a conveyor 33, which is caused to pick up the fiber mat falling through the receiver chute and transfer it to an outlet 34, from which the fiber mat proceeds for further processing. In the example shown, the conveyor 33 is a screw conveyor, which extends parallel to the rotor shaft 7 and is rotated by means of a drive means 35, for example in the form of a drive motor.

As the filter element 11 rotates, the filter sector 12 will dip into the suspension in the container 2 in the space 36 between the receiver chutes 30 and subsequently move through the suspension to the opposite side of the rotor shaft 7, where the filter sector 12 rotates upwards out of the suspension. As the filter sector 12 moves through the suspension, water is sucked out of the suspension, through the filter lining 13 on the filter sector 12 and into the flow channels inside the filter sector, while the fibres are deposited as a fibre mat on the outer surface of said filter lining. Filtrate comprising water then flows from the flow channel through the conduit section 15 to the filtrate channel 14 in the rotor shaft 7 and is discharged from the vessel 2 through the suction head 22 and one of the filtrate outlets 20, 21. When the filter sector 12 has rotated out of the suspension upwards, continued suction through the filtrate channels 14 in the rotor shaft 7 and the flow channels in the filter sector generates an air flow which passes through the fibrous material deposited on the filter lining 13 and further through the flow channels and into the filtrate channels 14. The fibrous material deposited on the filter liner 13 will be dried by the air flow. After having rotated through an angular position in which the filter sector 12 is oriented vertically upwards, the filter sector 12 is continuously rotated through a release member 25, which release member 25 releases the fibre mat from the filter lining 13 of the filter sector 12 by means of a fluid jet directed at the opposite lateral surface of the respective filter sector 12. As the rotor unit 6 continues to rotate, the filter sectors 12 then rotate past the cleaning members 26, which clean the filter linings 13 of the filter sectors 12 by means of rinsing liquid sprayed towards the opposite lateral surfaces of the respective filter sectors 12. The fibre mat loosened from the filter lining 13 of the filter sector falls into the receiver chute 30 together with the rinsing liquid from the cleaning member 26. At the bottom of the receiver chute 30, the fiber mat is picked up by a conveyor 33 and proceeds to be further processed. After rotating past the upper end of the cleaning member 26 and the receiver chute 30, the filter sector 12 is rotated down into the suspension again for a new filtration cycle.

The inlet 3 of the vessel 2 preferably comprises a plurality of inlet openings (not shown in fig. 1 and 2) in a portion of the vessel 2 where the filter sector 12 is rotated from a position above the suspension downwards into the suspension in the vessel during rotation of the rotor unit 6, the inlet openings being configured to introduce the suspension into the space 36 between the receiving troughs 30. The inlet 3 and its inlet opening are configured to let the suspension flow into the container 2 in a direction coinciding with the direction of rotation of the filter element 11.

In the embodiment shown in fig. 3, the inlet 3 of the vessel 2 comprises several inlet channels 40, which are positioned in the vessel 2 in a portion of the vessel where the filter sector 12 is rotated down into the suspension from a position above the suspension during rotation of the rotor unit 6. Each inlet channel 40 extends vertically side by side with one of the receiver chutes 30 of the disc filter, and the inlet channel 40 is positioned between the receiver chute and an adjacent portion of the peripheral wall 18 of the container 2. The respective inlet passage 40 is separated from the adjacent receiver chute 30 by a dividing wall 44. The lateral wall 37 of the respective receiver chute 30 is flush with the lateral wall 42 of the associated inlet channel 40. The inlet channel 40 is connected to a conduit 4 through which the suspension is fed to the inlet channel 40. Inlet openings 41 are positioned in the upper part of the inlet channel 40 to allow the suspension to flow from the inlet channel and through these inlet openings 41 into the space between the receiver chutes 30. These inlet openings 41 are provided in opposite lateral walls 42 of the respective inlet channel above the surface of the suspension in the vessel. The upper end of each inlet channel 40 is covered by an inclined roof 43 to prevent rinsing liquid and loose fibre mats from the cleaning member from falling into the inlet channel.

As shown in fig. 4, each receiver chute 30 is open at the top to provide an inlet opening 38 for receiving the fiber mat loosened from the filter lining of the adjacent filter element 11, as well as rinsing liquid from the cleaning members positioned above the receiver chute. In the embodiment shown in fig. 3 and 4, each receiver chute 30 is provided at its upper end with a portion 31 which is bent inwards into the area above the rotor shaft 7 to allow the inlet opening 38 of the receiver chute to extend into this area. However, it should be understood that other configurations of receiver chutes are contemplated and possible.

Referring now to fig. 5 and 6, and as described herein, embodiments of the disc filter 1 described herein further include at least one ejector 110. For example, the disc filter 1 may comprise a plurality of injectors 110 arranged adjacent each side of each filter element 11 in the space between each pair of adjacent filter elements 11 and in the space between the respective outermost filter element 11 and the end wall 9a, 9b of the adjacent container 2. Thus, in the embodiment depicted in fig. 5, the disc filter 1 comprises five injectors 110. However, it should be understood that the number of injectors 110 may be more than 5 or less than 5, depending on the number of filter elements 11 in the disc filter 1.

Typically, the injector 110 is positioned to direct a flow of a secondary liquid, such as water, fiber suspension, or the like, into the vessel. In an embodiment, the liquid flow may be directed onto the rotor shaft 7. In embodiments, the injector 110 may be shaped and positioned to minimize or mitigate contact between the secondary liquid flow and the surface of the filter element 11. In an embodiment, the injector 110 may be shaped and positioned to provide the secondary liquid flow at a sufficient pressure such that at least a portion of the flow contacts the rotor shaft 7. In these embodiments, the main flow vector 130 of each injector is orthogonal to the axis of rotation 131 of the rotor shaft 7. More specifically, in the embodiment, the rotor shaft 7 includes the rotation axis 131 in a shaft plane 144, which is a horizontal plane (i.e., a plane parallel to the X-Y plane of the coordinate axes shown in the drawing). The primary flow vector 130 of each injector 110 is generally orthogonal to the axis of the shaft. In some embodiments, the main flow vector 130 of each injector 110 may optionally be substantially parallel to (or even coplanar with) the axial plane 144. In some other embodiments, sparger 110 is oriented in the wall of vessel 2 such that main flow vector 130 of sparger 110 is at a non-zero angle relative to axial plane 144. In some embodiments, the primary flow vector 130 of at least some of the injectors 110 intersects the axis of rotation 131. In some other embodiments, the main flow vectors 130 of at least some of the injectors 110 are spaced from the axis of rotation in a positive or negative vertical direction (i.e., the positive or negative Z direction of the coordinate axes depicted in the figures). In an embodiment, the sparger 110 is positioned in the wall of the vessel 2 at a location proximal to the filter element 11, and on the opposite side of the vessel 2 from the inlet 3. In the embodiment shown in fig. 5 and 6, the sparger 110 is positioned in the wall of the vessel 2 at a location near the filter element 11 where the main component of the angular velocity vector ω (indicated by arrows/symbols 140 and 142) of the filter element 11 is in the positive vertical direction, while the inlet 3 is positioned in the wall of the vessel 2 at a location near the filter element 11 where the main component of the angular velocity vector ω of the filter element 11 is in the negative vertical direction (i.e. the negative Z-direction of the coordinate axes depicted in the figures). However, it is to be understood that other embodiments are contemplated and are possible. For example, in an alternative embodiment (not depicted), the sparger 110 is positioned in the wall of the vessel 2 at a location near the filter element 11 where the main component of the angular velocity vector ω of the filter element 11 is in the negative vertical direction, while the inlet 3 is positioned in the wall of the vessel 2 at a location near the filter element 11 where the main component of the angular velocity vector ω of the filter element 11 is in the positive vertical direction.

In the embodiments described herein, the sparger 110 is positioned in the wall of the vessel 2 at a vertical height that is above the axis of rotation 131 (i.e., in the positive Z-direction of the coordinate axes shown in the figures), below the axis of rotation 131 (i.e., in the negative Z-direction of the coordinate axes shown in the figures), or at the same vertical height as the axis of rotation 131. The vertical height is defined herein by injector elevation angle α relative to axial plane 144 as shown in FIG. 6_IAnd (4) limiting. It should be noted that as used herein, the injector elevation angle α of the injector 110_IRefers to the location of the sparger 110 along the wall of the vessel 2 relative to the axis plane 144, and not to the angular orientation of the sparger 110 about a particular axis. In the embodiments described herein, the injector elevation angle α_IGreater than-44 degrees and less than or equal to +22 degrees relative to the axial plane 144. In some embodiments, injector elevation angle α_IGreater than-22 degrees and less than or equal to +22 degrees relative to the axial plane 144. In some embodiments, injector elevation angle α_IGreater than-15 degrees and less than or equal to +15 degrees relative to the axial plane 144. In some embodiments, injector elevation angle α_IGreater than-10 degrees and less than or equal to +10 degrees relative to the axial plane 144. In thatIn some of these embodiments, the injector elevation angle α_IAt a non-zero angle with respect to the axial plane 144. For example, in some embodiments, injector elevation angle α_IGreater than 0 degrees and less than or equal to +22 degrees, or less than 0 degrees and greater than or equal to-44 degrees, relative to the axial plane 144. In some embodiments, injector elevation angle α_IGreater than 0 degrees and less than or equal to +22 degrees, or less than 0 degrees and greater than or equal to-22 degrees, relative to the axial plane 144. In some other embodiments, injector elevation angle α_I0 degrees relative to the axial plane 144. In these embodiments, the main flow vector 130 of the ejector may lie in the axial plane 144, or alternatively, in a plane parallel to the axial plane 144. In the embodiments described herein, the ejector 110 is generally positioned along the wall of the vessel 2 below the filling level 146 of the fiber suspension in the vessel 2, as depicted in fig. 6.

In an embodiment, the outlet of the eductor 110 is disposed between the outer radius of the filter element 11 and the wall of the vessel 2, as depicted in fig. 5 and 6. In an embodiment, the outlet of the injector 110 is arranged between the outer radius of the filter element 11 and the wall of the rotor shaft 7, as shown in fig. 7 and 8.

Referring now to fig. 5 and 9, in some embodiments, the injector 110, and in particular the outlet 111 of the injector 110, is shaped to minimize or mitigate contact between the secondary liquid flow from the injector 110 and the surface of the filter element 11, while optionally also providing the secondary liquid flow at sufficient pressure to cause the liquid to contact the rotor shaft 7 secondary liquid flow. In a particular embodiment, the outlet 111 of the injector 110 is shaped such that the liquid flow from the injector (as shown by flow cone 132 in FIG. 9) diverges from the main flow vector 130 of the injector 110 in a primarily +/-vertical direction while minimizing lateral divergence of the secondary flow from the main flow vector 130 (i.e., diverging in a +/-Y direction of the coordinate axes depicted in the figures). That is, the outlet 111 of the ejector is shaped to create a vertical liquid fan that is directed between adjacent filter elements 11, and in some embodiments onto the rotor shaft 7 with minimal surface contact with the filter elements 11. A flow jet having this configuration helps to minimize disruption of the fiber mat on the surface of the filter element 11 prior to removal of the fiber mat with the cleaning member 26.

Referring now to FIG. 10, in an embodiment, a vertical liquid fan is formed by configuring the outlet 111 of the ejector 110 with the outlet 111 having a major axis 150 in the +/-vertical direction (i.e., a direction parallel to the +/-Z direction of the coordinate axes) and a minor axis 152 in the transverse direction (i.e., a direction parallel to the +/-Y direction of the coordinate axes depicted in the figures) such that the length of the major axis 150 is greater than the length of the minor axis 152. Suitable geometries for the outlet 111 of the injector include, but are not limited to, elliptical, rectangular, oval, egg-shaped (ovoids), and the like.

Referring now to FIG. 11, in some embodiments, the width of the outlet 111 (i.e., the dimension of the outlet in the +/-Y direction) varies along the main axis 150. For example, in one particular embodiment, the width of the outlet 111 varies along the major axis such that the outlet 111 has a "dog bone" cross-section as depicted in fig. 11. In FIG. 12, a particular embodiment of an injector 110 having an outlet 111 is depicted, wherein the width varies along the major axis.

Although the outlet 111 of the injector is described herein as having a major axis 150 and a minor axis 152, wherein the major axis 150 has a length greater than the minor axis, it should be understood that other embodiments are contemplated and are possible. For example, in alternative embodiments (not shown), the outlet may be circular, square, octagonal, or the like. It will be appreciated that outlets having these configurations may also be used to generate a secondary fluid flow having sufficient pressure to contact the rotor shaft without disrupting the fibre mat deposited on the filter element 11.

Referring again to fig. 5 and 6, in the embodiment of the disc filter 1 described herein, the incorporation of the injector 110 at the location described helps to mitigate thickening of the fibre suspension at the region of the vessel 2 that is most susceptible to thickening. In particular, the introduction of the secondary liquid stream helps to dilute (i.e. thin) the fibre suspension in the tank, thereby reducing thickening. Furthermore, it has been unexpectedly found that providing the secondary liquid stream into the vessel 2 such that the secondary stream contacts the rotor shaft 7 causes sufficient agitation and mixing in the vessel opposite the inlet 3 to further reduce or mitigate thickening of the fibre suspension in the vessel. In particular, when the secondary liquid flow (indicated by primary flow vectors 130 in fig. 6) contacts rotor shaft 7, the secondary flow is reoriented and dispersed in multiple directions (i.e., vertical and between vertical and horizontal) as shown by scattering vectors 136 in fig. 6. This redirection and scattering of the secondary flow by the rotor shaft 7 produces agitation and mixing of the fiber suspension residing in the vessel 2, which helps to dilute the suspension residing in the vessel and to form a more homogeneous mixture of filtrate and fibers, thereby reducing or even mitigating the effects of thickening and mechanical scraping of the filter felt deposited on the filter element 11. Advantageously, it has been found that the agitation and mixing resulting from the secondary liquid flow directed onto the rotor shaft does not disrupt the deposition of the fiber mat on the filter element.

Still referring to fig. 5 and 6, the disc filter 1 may be configured to provide a certain flow ratio of liquid between the inlet 3 and the ejector 110. In these embodiments, the liquid may be, for example, a fiber suspension. This may be accomplished by various combinations of flow control components (e.g., pumps, valves, flow meters, etc.). For example, in some embodiments, each injector 110 is fluidly coupled to a supply manifold 108, which supply manifold 108 is in turn coupled to a pump 120 that provides a flow of liquid from a liquid source 200 (e.g., a tank, etc.) to the supply manifold 108. In an embodiment, the liquid source 200 may also be coupled to the main pump 180 that provides a liquid flow to the inlet 3. In this embodiment, the liquid is a fiber suspension and the liquid source 200 is a suspension source. However, it should be understood that in alternative embodiments, the main pump 180 may be coupled to a different liquid source. For example, in some embodiments (not shown), the pump 120 may be coupled to a secondary liquid source (such as a secondary suspension source, a secondary water source, etc.), and the main pump 180 may be coupled to a primary suspension source that is separate from the secondary liquid source. In yet other embodiments (not shown), a single pump (such as pump 120 or main pump 180) is used to couple a single levitation source to both supply manifold 108 and inlet 103. In such embodiments, one or more valves may be used to regulate the flow and pressure of the fiber suspension to the supply manifold 108 and the inlet 103.

In an embodiment, a secondary supply valve 116 may be disposed between the pump 120 and the supply manifold 108 to regulate the flow and pressure of liquid to the supply manifold 108, as depicted in fig. 5. However, it should be understood that the secondary supply valve 116 is optional and, in some embodiments, is not included.

Similarly, in some embodiments, a main supply valve 119 may be disposed between the main pump 180 and the inlet 3 to regulate the flow and pressure of liquid to the inlet 3, as depicted in fig. 5. However, it should be understood that the main supply valve 119 is optional and in some embodiments not included.

In an embodiment, the disc filter 1 may comprise a secondary feed flow meter 122 arranged between the pump 120 and the feed manifold 108. The secondary feed flow meter 122 may be used to monitor the flow rate and/or pressure of the liquid fed by the pump 120 to the feed manifold 108. However, it should be understood that the secondary feed flow meter 122 is optional, and in some embodiments, the disc filter 1 is configured without the secondary feed flow meter 122.

In an embodiment, the disc filter 1 may comprise a main supply flow meter 123 arranged between the main pump 180 and the inlet 3. The main supply flow meter 123 may be used to monitor the flow rate and/or pressure of the liquid supplied by the main pump 180 to the inlet 3. However, it should be understood that the main supply flow meter 123 is optional, and in some embodiments, the disc filter 1 is configured without the main supply flow meter 123.

In embodiments of the disc filter 1 comprising the secondary supply valve 116 and/or the primary supply valve 119, the supply valves may be manually operated, while in other embodiments the supply valves 116, 119 are electrically or pneumatically operated, such that they may be remotely actuated by a control system (not shown) such as communicatively coupled to the supply valves. In such embodiments, the pump 120 and the main pump 180 may also be communicatively coupled to the control system such that the flow rate and pressure of the liquid into and through the supply manifold 108 and the inlet 3 may be remotely controlled and/or regulated. In embodiments where the disc filter 1 includes a control system, the secondary supply flow meter 122 and the primary supply flow meter 123 may be communicatively coupled to the control system, thereby enabling automatic monitoring of the flow and/or pressure of liquid to and through the supply manifold 108 and the inlet 3. In some of these embodiments, such as those in which secondary supply flow meters 122 and 123 and secondary supply valves 116 and 119 are included, the control system may use supply flow meters 122, 123 in conjunction with supply valves 116, 119 and/or pumps 120, 180 to facilitate feedback control of liquid flow to and through supply manifold 108 and inlet 3.

Still referring to fig. 5 and 6, in some embodiments, each injector 110 is optionally coupled to the supply manifold 108 through an injector valve 114. When included, the eductor valves 114 may be used to regulate and regulate the flow and pressure of liquid from the supply manifold 108 to and through each eductor. For example, the injector valves 114 may be used to individually adjust the flow rate and pressure of liquid to and through each injector 110. Thus, it should be understood that in some embodiments, the flow rate and/or pressure of the liquid through each injector 110 may be adjusted individually. In some embodiments, the injector valve 114 may be manually operated, while in other embodiments, the injector valve 114 is electrically or pneumatically operated such that the injector valve 114 may be remotely actuated by a control system (not shown) or the like communicatively coupled to the injector valve 114. In such embodiments, the pump 120 and the main pump 180 may also be communicatively coupled to the control system such that the flow rate and pressure of the liquid into and through the eductor 110 may be remotely controlled and/or adjusted.

While fig. 5 schematically depicts the injector 110 coupled to the supply manifold 108 through the injector valve 114, it should be understood that the injector valve 114 is optional, and in some embodiments, the injector 110 is coupled to the supply manifold 108 without the injector valve 114.

In some embodiments, each injector 110 is coupled to the supply manifold 108, optionally through a flow meter 112. In embodiments where the injector 110 is coupled to the supply manifold 108 through an injector valve 114, the flow meter 112 is positioned between the injector valve 114 and the injector 110, as depicted in fig. 5. The flow meter 112 may be used to monitor the flow and/or pressure of the liquid from the supply manifold 108 to the injector 110. In embodiments in which the disc filter 1 comprises a control system, the flow meter 112 may be communicatively coupled to the control system, thereby enabling automatic monitoring of the flow rate and/or pressure of the liquid to and through the injector 110. In some of these embodiments, such as those including flow meter 112 and/or injection valve 114, the control system may use flow meter 112 in conjunction with injection valve 114 and/or pump 120 or main pump 180 to facilitate feedback control of the flow and pressure of the liquid through injector 110.

While fig. 5 schematically depicts the injector 110 coupled to the supply manifold 108 by a flow meter 112, it should be understood that the flow meter 112 is optional, and in some embodiments, the injector 110 is coupled to the supply manifold 108 without the flow meter 112.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the present specification cover the modifications and variations of the various embodiments described herein provided they come within the scope of the appended claims and their equivalents.