CA2212946A1 - Apparatus for filtering liquids - Google Patents
Apparatus for filtering liquidsInfo
- Publication number
- CA2212946A1 CA2212946A1 CA002212946A CA2212946A CA2212946A1 CA 2212946 A1 CA2212946 A1 CA 2212946A1 CA 002212946 A CA002212946 A CA 002212946A CA 2212946 A CA2212946 A CA 2212946A CA 2212946 A1 CA2212946 A1 CA 2212946A1
- Authority
- CA
- Canada
- Prior art keywords
- vat
- compartment
- liquid
- passage
- filter body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D33/00—Filters with filtering elements which move during the filtering operation
- B01D33/15—Filters with filtering elements which move during the filtering operation with rotary plane filtering surfaces
- B01D33/21—Filters with filtering elements which move during the filtering operation with rotary plane filtering surfaces with hollow filtering discs transversely mounted on a hollow rotary shaft
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D33/00—Filters with filtering elements which move during the filtering operation
- B01D33/70—Filters with filtering elements which move during the filtering operation having feed or discharge devices
- B01D33/72—Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding
- B01D33/722—Filters with filtering elements which move during the filtering operation having feed or discharge devices for feeding containing fixed liquid displacement elements or cores
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/28—Position of the filtering element
- B01D2201/282—Filtering elements with a horizontal rotation or symmetry axis
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Paper (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Filtration Of Liquid (AREA)
Abstract
An apparatus for filtering liquids has a vat (2) in which a hollow filter body (1) having an operative horizontal extension is arranged. There is provided an inlet means which comprises a portion of the vat wall forming at least one passage (11) for the liquid to be filtered, and a deflecting means (13) positioned in the vat between said portion of the vat wall and the filter body and adapted to deflect liquid flowing into the vat through said passage, such that the liquid reaches the filter body substantially evenly distributed along said operative horizontal extension thereof.
Description
W O 96~25218 1 PCT/SE96/00163 APparatus for filtering liquids The present invention relates to an apparatus for filtering 5 liquids, such as fibre pulp suspension or polluted water.
A common type of such a filtering apparatus includes a vat having a wall, and a hollow filter body having an operative horizontal extension and positioned in the vat. There are 10 inlet means for supplying the liquid to be filtered into the vat outside the filter body, coarse fraction outlet means for discharging developed coarse fraction from the apparatus, and fine fraction outlet means for discharging developed fine fraction from the interior of the hollow filter body.
In this type of filtering apparatus the inlet means conventionally includes a trough located outside the vat and extendinq along said operative hori20ntal extension of the filter body. The liguid to be filtered is initially supplied 20 to this inlet trough and is distributed from the trough across a weir to the vat whereby the li~guid is more or less evenly spread in the vat along the operative horizontal extension of the filter body. This inlet trough usually has a considerable long outer wall which is exposed to a relatively 25 strong pressure exerted by the liquid in the trough. In consequence said long wall of the trough has to be thick enough or be provided with reinforcements to withstand the liquid pressure. Therefore, such a conventional inlet trough is relatively expensive and adds significantly to the cost of 30 the filtering apparatus.
The conventional inlet trough also suffers from other dis-advantages. Firstly, the liquid to be filtered is often unevenly distributed along the operative horizontal extension 35 of the filter body, i. e. the liquid flow toward the filter body is larger in the middle of the filter body than at the ends of 'he filter body. Secondly, when filterins fibre pulp suspensions fibres tend to build up sediment in the trough.
Thirdly, the liquid flowing across the weir into the vat can create a lot of foam, which disturbs the filtering process.
Forthly, the long inlet trough outside the v~t takes up a lof 5 of space.
An object of the present invention is to provide a filtering apparatus having a less expensive inlet means, as compared with the conventional apparatus.
Another object of the present invention is to provide a filtering apparatus which has a superior performance to the conventional apparatus in the sense that the incoming liquid is evenly distributed along the operative horizontal 15 extension of the filter body, the build-up of sediment is counteracted, and foam creation is reduced.
Yet another object of the present invention is to provide a filtering apparatus which takes up less space than the 20 conventional apparatus.
These objects are fulfilled by means of a filtering apparatus of the common type described above characterized in that the inlet means comprises a portion of the vat wall forming at 25 least one passage for the liquid to be filtered extending from outside the vat to the interior thereof, and deflecting means positioned in the vat between said portion of the vat wall and the filter body and ada~ted to deflect liquid flowing into the vat through said passage, such that the 30 liquid reaches the filter body substantially evenly distri-buted along said operative horizontal extension thereof.
Thus, a conventional inlet trough is not necessary and can be eliminated which substantially reduces the fabrication cost of the apparatus.
According to a preferred embodiment of the inven'ion, the deflecting means comprises a partition wall dividing the W 096/25218 3 PcT/~5G~ 63 interior of the vat into a first compartment, into which said passage opens, and a second compartment, in which the filter body is situated. The partition wall makes it possible in a easy way to deflect incoming liquid upwardly or downwardly or 5 both ways. If the liquid is to be deflected upwardly, the partition wall and the vat can define at least one upper opening situated above said passage. If the liquid is to be deflected downwardly the partition wall and the vat can define at least one lower opening situated below said 10 passage. If desired the liquid can be deflected into two part streams, one flowing upwardly and the other flowing down-wardly, by providing both the upper and lower openings.
According to an embodiment of the invention, the deflecting 15 means comprises a flow control means for controlling the liquid flow through said upper opening or said lower opening or both openings. If the flow control means controls the liquid flow through said lower opening, the velocity of the downwardly flowing liquid can be controlled so that 20 sedimentation on the bottom of the vat is avoided.
The invention is explained below in more detail by way of example with reference to the accompanying drawings in which Figure l is a side view, partly sectioned , of a prior art 25 apparatus, Figure 2 is a side view, partly sectioned, of an apparatus of the invention, Figures 3 to 6 are parts of sec'ional views of c._fferent embodiments of the apparatus according to the invention, 30 Figures 7 and 8 are sectional views taken along lines VII-VII
and VIII-VIII, respectively, of Figure 6, Figure 9 is part of a control valve, Figure lO is a modification of the control valve shown in Figure 9, and 35 Figures 11 to 13 are parts of sectional views of d_fferen' embodiments of a control valve for the apparatus of the ir.ven'ior..
In ~ig. 1 there is shown a conventional rotary disc filtering apparatus including a plurality of coaxial hollow discs 1 having side walls of filter material, the discs 1 forming a 5 row having an operative axial extension, and a vat 2 in which the discs 1 are arranged rotatable about a horizontal axis 3.
There is inlet means for the liquid to be filtered including a trough 4 which is arranged outside the vat 2 and which extends axially along the discs 1. Liquid supplied to the 10 trough 4 flows across a weir 5 into the vat 2. Coarse fraction developed on the side walls of the discs 1 is discharged by an o~tlet means 6 and fine fraction developed within the hollow discs 1 is discharged by a fine fraction outlet means 7. The discs 1 are rotated about said horizontal 15 axis 3 by a drive motor 8. The vat 2 is provided with two outer elongated beams 9 supported ~y plinths 10.
Fig. 2 shows an apparatus of the invention which is similar to the conventional disc filtering apparatus of Fig 1, except 20 that the inlet means for the liquid to be filtered is different. Thus, the inlet means of the apparatus of Fig. 2 comprises a portion of the wall of the vat 2 forming a plurality of passages extending from outside the vat 2 to the interior thereof. The passages 11 communicate with 'he 25 interior of a horizontal pipe 12 through corresponding holes on the pipe 12. The inlet means furter comprises deflecting means, which in this case takes the form of a partition wall 13 positioned in the vat 2 between said portion of the vat wall and the discs ' and adapted to deflect liquic flowinc 30 into the vat 2 through the passages 11, such that the liquid reaches the filter discs 1 substantially evenly distri~uted along the operative axial extension of the _ow of discs 1 The partltion wall 13 divides the interior of the vat 2 into a first compartment 1~, into which the passages 11 opens and 35 a second compartmen' '5, in which the discs 1 are situated The passages 11 are dimensioned such that the flows of liquid through the respective passage~ 1 are substantially equal.
With reference to Fig. 3, the partition wall 13 and the vat 2 define an upper opening 16 situated ab~ve the passages 11 and a lower opening 17 situated below the passages 11. As a 5 result a first part stream and a second part stream, respectively, of the liquid flowing into compartment 14 is deflected upwardly through the upper opening 16 and down-wardly through said lower opening 17, respectively, into compartment 15. The upper opening 16 is located such that the 10 liquid level in compartment 15 is well above the partltion wall 13, whereby creation of foam is counteracted as said first part stream of liquid flows from compartment 14 to compartment 15. Since the liquid pressure on the partition wall 13 is insign ficantly stronger in compartment 14 than in 15 compartment 15, the partition wall 13 can be made designed a wall thickness which is considerably smaller than 'hat of the inlet trough of the conventional a-pparatus.
In Fig.4 there is shown an alternative embodiment in which 20 only an upper opening 18 is provided and a partition wall 19 is designed to form an upwardly converging flow area toward a level between the passage 11 and the opening 18. From said level the flow area diverges toward the opening 18. The upwardly converging part 20 of the compartment lga crea'es a 25 liquid flow resistance resulting in an even distribution of the liquid flow along the operative axial extension of the row of discs 1. The diverying part 21 of the compartment 14a has the effect of a diffusor resluting in a regain of the liquid pressure energy that was lost in the converging part 30 of the compartment 14a.
To a~hieve a desired distribution effect, the velocity o the liquid flow past the narrowest part of the compartment l~a has to be relatively high (for example 5 metre/second). ~hen 35 starting up the apparatus, said high velocity of the liquid low has the consequence tha~ liquid can be flushed up above the surface level 2q o' the llauid in the vat 2. This liquid CA 022l2946 l997-08-l2 flush is eliminated by providing a guide wall 23 above the upper opening 18, the guide wall 23 suitably being designated to direct the liquid flow downwardly into the vat 2.
5 If there is a risk for particle sedimentation in the vat 2, a number of lower openings 24 may be provided in the partition wall 14a. In case the apparatus only has a few discs 1, only one passage ' through the vat wall may be necessary.
10 Fig. 5 shows another alternative embodiment in which the partition wall 13~ only defines a lower opening 25. This embodiment is preferred when a maximal downwardly directed liquid flow is required to avoid sedimentation.
15 In Fig. 6 there is shown an embodiment simila~ to that of ~ig. 3 in which an upper control valve 26 is provided to control the sizes of the liquid flows through the upper opening 16 and the lower opening 17. The control valve 26 comprises a horizontal, turnable angle bar 27 having an axial 20 extension which corresponds to the distance between opposite wdll portions of the vat 2. The angle bar 27 has two pivot arms 28 which are journalled in bearings 28a on the vat 2.
The angle bar 27 is pivotable by a lever 29 which is loc~sable by a locking means 29a in desired positions, whereby the 25 through flow area in the direction upwardly in the com-partment 14 past the angle bar 27 is adjustable.
A lower control valve 30 (Figs. 6 and 11), which in principle is designed similar to the upper control valve 26, i.e.
30 comprising an angle bar 31, pivot arms 32, bearings 33, a lever 34 and a locking means 35. Thus, upon turning of the angle bar 31 by means of the lever 34" the through flow area in the direction downwardly in the compartment 14 past the angle bar 31 is adjusted. The adjustment of the angle bar 31 35 affects the sizes of the upper and lower liquid flows in the compartment 14 and enables a control of the flow velocity downwardly into compartment 15.
Fig. 10 shows an alternative embodiment of the angle bar. In this case the angle bar 36 comprises a number of recesses 37,38, which are passed by the liguid flow.
~ 5 In Figs. 8 and 12 there is shown an elongated guide plate 39 above the upper control valve 26. (Alternatively, the guide plate 39 may be positioned below the control valve 26.) The guide plate 39 guides the liquid flow to avoid flushing above 10 the surface 40 of the liquid in the vat 2. (In certain applications it may be suitable to supplement with the guide wall 23 shown in Fig. 4.). The liguid flowing upwardly from the compartment 14 flows further across a weir 41 and the surface 42 of the liquid in the vat 2 is situated below the 15 weir 41 (Fig.6~.
To eliminate the risk of liquid flowing across the weir 41 and affecting the discs 1 such that parts of the fibre mats on the discs 1 are flushed away, guide plates 43 are provided 20 for guiding the liquid flow to avoid hittlng the discs 1. The guide plates 43, suitably having U-cross-section, are positioned above the weir 41 and has an axlal extension which is larger than the breadth of a disc 1.
25 In case the hollow filter body takes the shape of a rotary drum, it is preferable to use the guide wall 23 shown in Fig.
4. In such a case the guide wall 23 also serves to prevent the upper liquid flow from flushing away parts of the mat of fibres on the drum.
The embodiment shown in Fig. 13 is similar to that of Figs. 6 and 12, except that the controllable through flow area is provided between the vat 2 and the angle bar 44. A further controllable flow restricting passage 45 is provided between 35 the angle bar 44 and an axial guide wall 46 on the vat 2.
(The same effect is also achievable with the embodiment according to Fig.12, in which a further flow restricting CA 022l2946 l997-08-l2 W 096/25218 PCTI~h~./00163 passage 47 occurs between angle bar 27 and the guide plate 3~.) As a price-worthy alternative, one of the two hollow beams 9 5 may also be utilized as a part of the liquid inlet means.
~uch an alternative is shown in Fig. 6 and comprises a hollow beam 48 which is provided with an inlet member 49 and a number of passages 50 through the wall of the vat 2. In this case the beam 48 also serves as an reinforcement of the wall lO of the vat 2.
Many combinations of the embodiments described above are concievable. For example the guide plate 23 may be combined with the embodiments shown in Fig. 3 and 6. In practice only 15 one of the two control valves 26 and 30 may be used and possibly in combination with the partition wall l9. In some applications the two embodiments according to Figs. 4 and 5 may be installed in the same vat. In such a case the liquid distribution can be controlled by valves outside the vat.
In the embodiments of the invention shown in the drawings, the liguid inlet means is provided at the descending side of the discs while the outlet means for discharging developed coarse fraction is provided at the ascending side of the 25 disc. As an alternative, both the liquid inlet means and the coarse fraction outlet means may be provided at the ascending side of the discs.
A common type of such a filtering apparatus includes a vat having a wall, and a hollow filter body having an operative horizontal extension and positioned in the vat. There are 10 inlet means for supplying the liquid to be filtered into the vat outside the filter body, coarse fraction outlet means for discharging developed coarse fraction from the apparatus, and fine fraction outlet means for discharging developed fine fraction from the interior of the hollow filter body.
In this type of filtering apparatus the inlet means conventionally includes a trough located outside the vat and extendinq along said operative hori20ntal extension of the filter body. The liguid to be filtered is initially supplied 20 to this inlet trough and is distributed from the trough across a weir to the vat whereby the li~guid is more or less evenly spread in the vat along the operative horizontal extension of the filter body. This inlet trough usually has a considerable long outer wall which is exposed to a relatively 25 strong pressure exerted by the liquid in the trough. In consequence said long wall of the trough has to be thick enough or be provided with reinforcements to withstand the liquid pressure. Therefore, such a conventional inlet trough is relatively expensive and adds significantly to the cost of 30 the filtering apparatus.
The conventional inlet trough also suffers from other dis-advantages. Firstly, the liquid to be filtered is often unevenly distributed along the operative horizontal extension 35 of the filter body, i. e. the liquid flow toward the filter body is larger in the middle of the filter body than at the ends of 'he filter body. Secondly, when filterins fibre pulp suspensions fibres tend to build up sediment in the trough.
Thirdly, the liquid flowing across the weir into the vat can create a lot of foam, which disturbs the filtering process.
Forthly, the long inlet trough outside the v~t takes up a lof 5 of space.
An object of the present invention is to provide a filtering apparatus having a less expensive inlet means, as compared with the conventional apparatus.
Another object of the present invention is to provide a filtering apparatus which has a superior performance to the conventional apparatus in the sense that the incoming liquid is evenly distributed along the operative horizontal 15 extension of the filter body, the build-up of sediment is counteracted, and foam creation is reduced.
Yet another object of the present invention is to provide a filtering apparatus which takes up less space than the 20 conventional apparatus.
These objects are fulfilled by means of a filtering apparatus of the common type described above characterized in that the inlet means comprises a portion of the vat wall forming at 25 least one passage for the liquid to be filtered extending from outside the vat to the interior thereof, and deflecting means positioned in the vat between said portion of the vat wall and the filter body and ada~ted to deflect liquid flowing into the vat through said passage, such that the 30 liquid reaches the filter body substantially evenly distri-buted along said operative horizontal extension thereof.
Thus, a conventional inlet trough is not necessary and can be eliminated which substantially reduces the fabrication cost of the apparatus.
According to a preferred embodiment of the inven'ion, the deflecting means comprises a partition wall dividing the W 096/25218 3 PcT/~5G~ 63 interior of the vat into a first compartment, into which said passage opens, and a second compartment, in which the filter body is situated. The partition wall makes it possible in a easy way to deflect incoming liquid upwardly or downwardly or 5 both ways. If the liquid is to be deflected upwardly, the partition wall and the vat can define at least one upper opening situated above said passage. If the liquid is to be deflected downwardly the partition wall and the vat can define at least one lower opening situated below said 10 passage. If desired the liquid can be deflected into two part streams, one flowing upwardly and the other flowing down-wardly, by providing both the upper and lower openings.
According to an embodiment of the invention, the deflecting 15 means comprises a flow control means for controlling the liquid flow through said upper opening or said lower opening or both openings. If the flow control means controls the liquid flow through said lower opening, the velocity of the downwardly flowing liquid can be controlled so that 20 sedimentation on the bottom of the vat is avoided.
The invention is explained below in more detail by way of example with reference to the accompanying drawings in which Figure l is a side view, partly sectioned , of a prior art 25 apparatus, Figure 2 is a side view, partly sectioned, of an apparatus of the invention, Figures 3 to 6 are parts of sec'ional views of c._fferent embodiments of the apparatus according to the invention, 30 Figures 7 and 8 are sectional views taken along lines VII-VII
and VIII-VIII, respectively, of Figure 6, Figure 9 is part of a control valve, Figure lO is a modification of the control valve shown in Figure 9, and 35 Figures 11 to 13 are parts of sectional views of d_fferen' embodiments of a control valve for the apparatus of the ir.ven'ior..
In ~ig. 1 there is shown a conventional rotary disc filtering apparatus including a plurality of coaxial hollow discs 1 having side walls of filter material, the discs 1 forming a 5 row having an operative axial extension, and a vat 2 in which the discs 1 are arranged rotatable about a horizontal axis 3.
There is inlet means for the liquid to be filtered including a trough 4 which is arranged outside the vat 2 and which extends axially along the discs 1. Liquid supplied to the 10 trough 4 flows across a weir 5 into the vat 2. Coarse fraction developed on the side walls of the discs 1 is discharged by an o~tlet means 6 and fine fraction developed within the hollow discs 1 is discharged by a fine fraction outlet means 7. The discs 1 are rotated about said horizontal 15 axis 3 by a drive motor 8. The vat 2 is provided with two outer elongated beams 9 supported ~y plinths 10.
Fig. 2 shows an apparatus of the invention which is similar to the conventional disc filtering apparatus of Fig 1, except 20 that the inlet means for the liquid to be filtered is different. Thus, the inlet means of the apparatus of Fig. 2 comprises a portion of the wall of the vat 2 forming a plurality of passages extending from outside the vat 2 to the interior thereof. The passages 11 communicate with 'he 25 interior of a horizontal pipe 12 through corresponding holes on the pipe 12. The inlet means furter comprises deflecting means, which in this case takes the form of a partition wall 13 positioned in the vat 2 between said portion of the vat wall and the discs ' and adapted to deflect liquic flowinc 30 into the vat 2 through the passages 11, such that the liquid reaches the filter discs 1 substantially evenly distri~uted along the operative axial extension of the _ow of discs 1 The partltion wall 13 divides the interior of the vat 2 into a first compartment 1~, into which the passages 11 opens and 35 a second compartmen' '5, in which the discs 1 are situated The passages 11 are dimensioned such that the flows of liquid through the respective passage~ 1 are substantially equal.
With reference to Fig. 3, the partition wall 13 and the vat 2 define an upper opening 16 situated ab~ve the passages 11 and a lower opening 17 situated below the passages 11. As a 5 result a first part stream and a second part stream, respectively, of the liquid flowing into compartment 14 is deflected upwardly through the upper opening 16 and down-wardly through said lower opening 17, respectively, into compartment 15. The upper opening 16 is located such that the 10 liquid level in compartment 15 is well above the partltion wall 13, whereby creation of foam is counteracted as said first part stream of liquid flows from compartment 14 to compartment 15. Since the liquid pressure on the partition wall 13 is insign ficantly stronger in compartment 14 than in 15 compartment 15, the partition wall 13 can be made designed a wall thickness which is considerably smaller than 'hat of the inlet trough of the conventional a-pparatus.
In Fig.4 there is shown an alternative embodiment in which 20 only an upper opening 18 is provided and a partition wall 19 is designed to form an upwardly converging flow area toward a level between the passage 11 and the opening 18. From said level the flow area diverges toward the opening 18. The upwardly converging part 20 of the compartment lga crea'es a 25 liquid flow resistance resulting in an even distribution of the liquid flow along the operative axial extension of the row of discs 1. The diverying part 21 of the compartment 14a has the effect of a diffusor resluting in a regain of the liquid pressure energy that was lost in the converging part 30 of the compartment 14a.
To a~hieve a desired distribution effect, the velocity o the liquid flow past the narrowest part of the compartment l~a has to be relatively high (for example 5 metre/second). ~hen 35 starting up the apparatus, said high velocity of the liquid low has the consequence tha~ liquid can be flushed up above the surface level 2q o' the llauid in the vat 2. This liquid CA 022l2946 l997-08-l2 flush is eliminated by providing a guide wall 23 above the upper opening 18, the guide wall 23 suitably being designated to direct the liquid flow downwardly into the vat 2.
5 If there is a risk for particle sedimentation in the vat 2, a number of lower openings 24 may be provided in the partition wall 14a. In case the apparatus only has a few discs 1, only one passage ' through the vat wall may be necessary.
10 Fig. 5 shows another alternative embodiment in which the partition wall 13~ only defines a lower opening 25. This embodiment is preferred when a maximal downwardly directed liquid flow is required to avoid sedimentation.
15 In Fig. 6 there is shown an embodiment simila~ to that of ~ig. 3 in which an upper control valve 26 is provided to control the sizes of the liquid flows through the upper opening 16 and the lower opening 17. The control valve 26 comprises a horizontal, turnable angle bar 27 having an axial 20 extension which corresponds to the distance between opposite wdll portions of the vat 2. The angle bar 27 has two pivot arms 28 which are journalled in bearings 28a on the vat 2.
The angle bar 27 is pivotable by a lever 29 which is loc~sable by a locking means 29a in desired positions, whereby the 25 through flow area in the direction upwardly in the com-partment 14 past the angle bar 27 is adjustable.
A lower control valve 30 (Figs. 6 and 11), which in principle is designed similar to the upper control valve 26, i.e.
30 comprising an angle bar 31, pivot arms 32, bearings 33, a lever 34 and a locking means 35. Thus, upon turning of the angle bar 31 by means of the lever 34" the through flow area in the direction downwardly in the compartment 14 past the angle bar 31 is adjusted. The adjustment of the angle bar 31 35 affects the sizes of the upper and lower liquid flows in the compartment 14 and enables a control of the flow velocity downwardly into compartment 15.
Fig. 10 shows an alternative embodiment of the angle bar. In this case the angle bar 36 comprises a number of recesses 37,38, which are passed by the liguid flow.
~ 5 In Figs. 8 and 12 there is shown an elongated guide plate 39 above the upper control valve 26. (Alternatively, the guide plate 39 may be positioned below the control valve 26.) The guide plate 39 guides the liquid flow to avoid flushing above 10 the surface 40 of the liquid in the vat 2. (In certain applications it may be suitable to supplement with the guide wall 23 shown in Fig. 4.). The liguid flowing upwardly from the compartment 14 flows further across a weir 41 and the surface 42 of the liquid in the vat 2 is situated below the 15 weir 41 (Fig.6~.
To eliminate the risk of liquid flowing across the weir 41 and affecting the discs 1 such that parts of the fibre mats on the discs 1 are flushed away, guide plates 43 are provided 20 for guiding the liquid flow to avoid hittlng the discs 1. The guide plates 43, suitably having U-cross-section, are positioned above the weir 41 and has an axlal extension which is larger than the breadth of a disc 1.
25 In case the hollow filter body takes the shape of a rotary drum, it is preferable to use the guide wall 23 shown in Fig.
4. In such a case the guide wall 23 also serves to prevent the upper liquid flow from flushing away parts of the mat of fibres on the drum.
The embodiment shown in Fig. 13 is similar to that of Figs. 6 and 12, except that the controllable through flow area is provided between the vat 2 and the angle bar 44. A further controllable flow restricting passage 45 is provided between 35 the angle bar 44 and an axial guide wall 46 on the vat 2.
(The same effect is also achievable with the embodiment according to Fig.12, in which a further flow restricting CA 022l2946 l997-08-l2 W 096/25218 PCTI~h~./00163 passage 47 occurs between angle bar 27 and the guide plate 3~.) As a price-worthy alternative, one of the two hollow beams 9 5 may also be utilized as a part of the liquid inlet means.
~uch an alternative is shown in Fig. 6 and comprises a hollow beam 48 which is provided with an inlet member 49 and a number of passages 50 through the wall of the vat 2. In this case the beam 48 also serves as an reinforcement of the wall lO of the vat 2.
Many combinations of the embodiments described above are concievable. For example the guide plate 23 may be combined with the embodiments shown in Fig. 3 and 6. In practice only 15 one of the two control valves 26 and 30 may be used and possibly in combination with the partition wall l9. In some applications the two embodiments according to Figs. 4 and 5 may be installed in the same vat. In such a case the liquid distribution can be controlled by valves outside the vat.
In the embodiments of the invention shown in the drawings, the liguid inlet means is provided at the descending side of the discs while the outlet means for discharging developed coarse fraction is provided at the ascending side of the 25 disc. As an alternative, both the liquid inlet means and the coarse fraction outlet means may be provided at the ascending side of the discs.
Claims (11)
1. An apparatus for filtering liquids, such as fibre pulp suspensions or polluted water, including a vat having a wall, a hollow filter body having an operative horizontal extension and positioned in the vat, inlet means for supplying the liquid to be filtered into the vat outside the filter body, coarse fraction outlet means for discharging developed coarse fraction from the apparatus, and fine fraction outlet means for discharging developed fine fraction from the interior of the hollow filter body, characterized in that - the inlet means comprises a portion of the vat wall forming at least one passage for the liquid to be filtered extending from outside the vat to the interior thereof, and - deflecting means positioned in the vat between said portion of the vat wall and the filter body and adapted to deflect liquid flowing into the vat through said passage, such that the liquid reaches the filter body substantionally evenly distributed along said operative horizontal extension thereof.
2. An apparatus according to claim 1, wherein the deflecting means comprises a partition wall dividing the interior of the vat into a first compartment, into which said passage opens, and a second compartment, in which the filter body is situated.
3. An apparatus according to claim 2, wherein the partition wall and the vat define at least one upper opening situated above said passage, whereby liquid flowing into the first compartment is deflected upwardly through said upper opening into the second compartment.
4. An apparatus according to claim 2, wherein the partition wall and the vat define at least one lower opening situated below said passage, whereby liquid flowing into the first compartment is deflected downwardly through said lower opening into the second compartment.
5. An apparatus according to claim 2, wherein the partition wall and the vat define at least one upper opening situated above said passage, and at least one lower opening situated below said passage whereby a first part stream and a second part stream, respectively, of the liquid flowing into the first compartment is deflected upwardly through said upper opening and downwardly through said lower opening, respectively, into the second compartment.
6. An apparatus according to claim 3 or 5, wherein the deflecting means comprises a flow control means for controlling the liquid flow through said upper opening.
7. An apparatus according to claim 4 or 5, wherein the deflecting means comprises a flow control means for controlling the liquid flow through said lower opening.
8. An apparatus according to claim 2, wherein the first compartment has a horizontal cross-sectional area that decreases in the vertical direction from said passage.
9. An apparatus according to claim 8, wherein the horizontal cross-sectional area of the first compartment decreases from said passage to a level above the latter, and increases in the direction upwardly from said level.
10. An apparatus according to claim 3 or 5, wherein the upper opening is positioned such that the liquid flowing from the first compartment through the upper opening is directed downwardly into the second compartment.
11. An apparatus according to claim 1, futher comprising a horisontally extending hollow support beam for supporting the apparatus on the ground, the interior of the support beam communicating with said passage, whereby liquid to be filtered is supplied to the apparatus through said hollow suppport beam.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9500502A SE9500502D0 (en) | 1995-02-13 | 1995-02-13 | Inlet device for rotating filters |
| SE9500502-1 | 1995-02-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2212946A1 true CA2212946A1 (en) | 1996-08-22 |
Family
ID=20397179
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002212946A Abandoned CA2212946A1 (en) | 1995-02-13 | 1996-02-09 | Apparatus for filtering liquids |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0809528A1 (en) |
| AU (1) | AU4734896A (en) |
| CA (1) | CA2212946A1 (en) |
| FI (1) | FI973307A (en) |
| SE (1) | SE9500502D0 (en) |
| WO (1) | WO1996025218A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI123655B (en) * | 2011-09-02 | 2013-08-30 | Metso Paper Inc | A disc filter and a method for feeding a pulp suspension into a disc filter |
| DE102012213769A1 (en) * | 2012-08-03 | 2014-02-06 | Voith Patent Gmbh | disc filter |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4123144C1 (en) * | 1991-07-12 | 1992-11-19 | Werner Prof. Dr.-Ing. 6740 Landau De Stahl | |
| FI95660C (en) * | 1994-06-10 | 1998-07-14 | Ahlstrom Machinery Oy | Disc filter feeder |
-
1995
- 1995-02-13 SE SE9500502A patent/SE9500502D0/en unknown
-
1996
- 1996-02-09 EP EP96903296A patent/EP0809528A1/en not_active Withdrawn
- 1996-02-09 WO PCT/SE1996/000163 patent/WO1996025218A1/en not_active Application Discontinuation
- 1996-02-09 CA CA002212946A patent/CA2212946A1/en not_active Abandoned
- 1996-02-09 AU AU47348/96A patent/AU4734896A/en not_active Abandoned
-
1997
- 1997-08-12 FI FI973307A patent/FI973307A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU4734896A (en) | 1996-09-04 |
| FI973307A0 (en) | 1997-08-12 |
| WO1996025218A1 (en) | 1996-08-22 |
| EP0809528A1 (en) | 1997-12-03 |
| FI973307A (en) | 1997-10-09 |
| SE9500502D0 (en) | 1995-02-13 |
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