WO1997018025A1

WO1997018025A1 - Plate separator equipped with movable plates

Info

Publication number: WO1997018025A1
Application number: PCT/SE1996/001495
Authority: WO
Inventors: Anders Hansen; Ulf Ericson
Original assignee: Anders Hansen; Ulf Ericson
Priority date: 1995-11-16
Filing date: 1996-11-18
Publication date: 1997-05-22
Also published as: SE9504121D0; SE505662C2; SE9504121L

Abstract

The invention relates to an apparatus and a method for separating particles from liquid or for separating liquids of different densities from one another. The apparatus includes a container (14) with an inlet (9) in its lower region for a liquid containing particles or for a mixture of liquids of different densities, and with an outlet (10) in its upper region for supernatant. A bottom pocket (6) is provided for accumulating particles or liquid which have been separated (sedimented). The bottom pocket is provided with an outlet (7). Two or more switchable, angled lamellae (13) are disposed between the inlet (9) for liquid and the outlet (7) for supernatant. Spaces (2, 4) which are connected in series are formed between the angled lamellae. According to the method, the lamellae (13) are set such that the separation (sedimentation) alternatingly takes place in concurrent flow chambers (2) and in countercurrent flow chambers (4). The sedimented particles or the sedimented liquid are displaced along the lamellae to two opposing walls in the container and along these two the bottom pocket (6). This is emptied of its content through the outlet (7).

Description

PLATE SEPARATOR EQUIPPED WITH MOVABLE PLATES

The present invention relates to an apparatus and a method for separat¬ ing particles from liquid or for separating liquids of different densi¬ ties from one another, according to the preamble to the appended inde¬ pendent claims.

Sedimentation is an often employed technique for separating suspended material from liquids in industrial processes. The present invention relates to an apparatus and a method which includes sedimentation for separating material (particles) which is suspended in a liquid. Herein¬ after, the word "sludge" will be often employed without any restrictive meaning for designating the material which is separated from the liquid. The apparatus is also suitable for separating two liquids of different densities from one another.

Since the end of the 1960's, lamella sedimentation has been employed for separating particles, for example sludge, from liquids. The prin¬ ciple of lamella sedimentation is based on the concept that the liquid containing the suspended particles is caused to flow between obliquely inclined panels or lamellae on which the particles sediment. After the sedimentation, the particles slide off the obliquely inclined lamellae and down into a sludge pocket. Depending upon the flow direction of the liquid in relation to the displacement direction of the particles in the sedimentation, the terms concurrent or countercurrent sedimentation are employed. In countercurrent sedimentation, the flow direction of the liquid is opposite to that direction in which the particles move in the sedimentation, while the flow direction for the liquid and the movement direction of the particles coincide in concurrent sedimen¬ tation.

A particle which it is intended to be separated from a liquid by sedi- mentation is affected by the force of gravity and those forces which the liquid exercises on the particle. The fundamental theory for sedi¬ mentation is Hazen's surface treatment theory which, in simple terms, takes as its point of departure that the particles which are intended to be separated should have reached the bottom of the sedimentation basin before the liquid leaves the basin. This implies that the flow path for the liquid in a sedimentation basin must be given such length that the particles will reliably have time to settle and sediment be¬ fore the liquid leaves the sedimentation basin.

In practice, the sedimentation cycle does not entirely comply with the surface treatment theory, which presupposes laminary and stable flow. Disruptions of various types occur in the sedimentation basins, for example strata flow, return flow at the inlet, and so on. In general, no more than approximately 60% sedimentation effect is achieved in the use of sedimentation basins as compared with the theoretical value. In dimensioning of sedimentation basins, it is therefore necessary that the liquid be given a considerably longer flow path than that which is theoretically sufficient to achieve the desired sedimentation effect.

It is obvious that there are needs for as compact a sedimentation appa¬ ratus (separator) as possible, i.e. the intention is to employ the least possible floor space while retaining (and preferably improving) the separation capability compared to existing plants. In addition to the fact that the smaller apparatus requires less space and thereby, as a rule, also lower premises costs, a smaller apparatus is per se gener¬ ally cheaper.

The present invention relates to an apparatus and a method in which the above-outlined needs are satisfied. This is put into effect employing the technique disclosed in the characterizing clauses of the independent claims.

The apparatus (the separator) according to the invention includes sec¬ tions in which a concurrent sedimentation takes place and sections in which a countercurrent sedimentation takes place. The apparatus is pro¬ vided with movable lamellae whose position is changed such that sedi- mentation between two adjacent lamellae alternatingly takes place con¬ currently and countercurrently. This switching between countercurrent and concurrent sedimentation entails that the apparatus is self-clean¬ ing.

Unlike sedimentation basins, the separator according to the present in- vention utilizes as good as all of its liquid height for sedimentation, which maximizes the separation capability per unit of volume and mini¬ mizes the risk of flotation. The effective utilisation of the liquid height is achieved in that the liquid is forced to follow a path where the spaces or chambers which the lamellae form between them are con- nected in series in terms of flow. On the other hand, when sludge is emptied out of the separator, the chambers are connected in parallel in terms of flow, which entails an extremely effective emptying of the chambers. Since the sludge, when it has left the chamber, only passes one subsequent chamber in an edge region thereof and only along a rela- tively short distance, the risk that sedimented sludge is once again suspended in the liquid during the emptying operation is reduced to a minimum.

The space between the lamellae varies depending upon the position of the lamellae. The lamellae are disposed such that the flow area is greatest in those spaces where sedimentation takes place countercur- rently, for which reason the flow rate will be lower in the countercur¬ rent separation than in the concurrent separation. The lamella angle in relation to the liquid surface is thus greater in the countercurrent space than in the concurrent space, which assists the sedimentation cycle.

Expedient embodiments of the present invention are disclosed in the appended subclaims.

Embodiments of the present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawings. In the accompanying Drawings:

Fig. 1 is a cross section through the apparatus, with the lamel¬ lae of the apparatus in a first position; Fig. 2 is a cross section through the apparatus corresponding to the section of Fig. 1, with the lamellae of the apparatus in a second position;

Fig. 3 is a cross section through the apparatus corresponding to the section of Fig. 1, with the lamellae of the apparatus in a third position;

Fig. 4 is a cross section through the apparatus corresponding to the section of Fig. 2 with the apparatus set for removal of sediment separated from the liquid;

Fig. 5 is a cross section corresponding to Fig. 2, showing one embodiment of the apparatus with elastically resilient la- ellae;

Fig. 6 is a cross section through one embodiment employing fixed lamellae; and

Figs. 7a-c show a cross section corresponding to the previous sec¬ tions in which the lamellae are straight.

The apparatus according to the present invention includes a tank or container 14 in which particles dispersed in the liquid are separated from the liquid, or liquids of different densities are separated from one another. In top plan view, the container 14 has a substantially rectangular or quadratic inner configuration. An inlet pipe 1 for the liquid containing the particles or for the mixture of liquids of dif¬ ferent densities leads to the container 14, the pipe 1 discharging in an inlet 9 in the bottom section 23 of the container 14. The upper sec¬ tion 22 of the container is provided with an outlet 10 which is gener¬ ally designed as a spillway overflow 10.

In order to simplify this description, the apparatus will be described hereinbelow when it is employed for separating particles suspended in the liquid, but it will be obvious to the skilled reader of this speci¬ fication that, in a mixture of liquids of different densities, the liquids will separate into strata when the liquid of the greater den¬ sity sinks down in a manner corresponding to that which applies for particles which are suspended in a liquid and which are of greater den¬ sity than the liquid itself.

The inlet 9 of the container and/or means 8 cooperating with the inlet (hereinafter also referred to as spreader 8) are disposed such that the liquid supplied to the container is to be spread (distributed) such that the infed liquid forms a calm and uniform flow from the bottom section 23 of the container to its upper section 22.

In one embodiment, a spreader 8 is designed as a substantially planar plate which forms passages 19 between its opposing edges 16 and the in¬ ner defining walls 20 of the container. The plate is disposed to spread the flow of the supplied liquid out towards the edges of the plate and in order thereby to ensure the desired slow and uniform flow of liquid from the bottom section 23 of the container to the spillway overflow 10.

In the embodiment of the present invention illustrated in Figs. 1-4 the spreader 8 consists of two discs 8a,b which make an angle with one another and are placed a short distance above the mouth 24 of the inlet 9. The discs form a roof-like construction with the angle apex facing upwards, and disposed centrally above the inlet 9. The lower edges 16 of the discs are shown in the Figures as drawn down so that the edges are located on a level which is lower than the level of the mouth of the inlet 9.

A first sludge pocket 6, hereinafter also designated bottom sludge pocket 6, is disposed in the bottom section 23 of the container. The bottom sludge pocket is disposed on a lower level than the mouth 24 of the inlet. In the illustrated embodiment, the inlet 9 passes through the bottom sludge pocket. The bottom 21 of the container forms the bot¬ tom sludge pocket 6 which has bottom surfaces with a slope which leads sludge accumulated in the pocket towards a sludge outlet 7. A valve (not shown) is provided for opening and closing the sludge outlet 7 at suitable times, as will be described in greater detail hereinbelow in connection with the description of an operational cycle for the ap¬ paratus.

A number of movable lamellae 13 are disposed above the inlet 9. In em- bodiments in which the spreader 8 is included, the lamellae are dis¬ posed above the spreader. In the illustrated example, the lamellae are four in number, but this number varies from one embodiment of the present invention to another. The number of lamellae 13 is essentially determined by the distance it is desired that the liquid flow is to pass before leaving the container 14. The desired distance is deter¬ mined, amongst other things, by the expected concentration of sludge in the liquid which is supplied into the apparatus and the purity which it is desired to attain for the liquid which departs from the apparatus.

In the illustrated embodiment, all movable lamellae 13 are of cor¬ responding construction. The lamella 13 consists of two lamella panels 15a,b united with one another so as to make an angle α. In one embodi¬ ment, the lamellae 13 are of one piece construction in that, for example, a plate is bent to the desired angle α. The tip of the thus formed angle in the lamellae 13 is, with the lamellae placed in the container, directed upwards. As a rule, the lamellae are arranged such that their upper edge 26 slopes a few degrees towards the horizontal in order that possible air bubbles do not remain in the fold of the la¬ mella.

In one alternative embodiment, the lamellae 13 are manufactured in that two lamella panels 15a,b are joined together for forming the desired angle , this angle being approx. 95° in the illustrated embodiment.

In the embodiment which is shown in Fig. 5, the panels 15a,b of the la¬ mellae are somewhat flexible in order to permit a certain bending in connection with the switching between different positions as described below. It will be apparent from the Figure that the lamella panels, on abutment against the wall 17 of the container, bend slightly while the lamella panels return to an almost planar form when the panels are re¬ moved from the wall of the container. The lamellae may also be made of plastic material. In order to avoid the risk that sludge adheres to the lamellae, a non-hydrophilic ma¬ terial is selected. Lamellae of metal are generally provided with a coating of non-hydrophilic material.

The expression lamella 13 is taken, in this description, to signify the entire lamella, and the expression lamella panel 15a,b is taken to signify a part of the lamella 13, namely that part which, in the creased or folded lamella, extends from the angle apex to the one lower edge of the lamella, irrespective of how the lamella 13 is manufactured or constructed (cf. Figs. 1-5). The expressions lamella and lamella panel, respectively, are employed irrespective of whether the lamella is of one piece manufacture or whether it is composed of several parts.

The lamellae 13 are of a length which corresponds to the inner length of the container 14, this length relating to the extent at right angles to the plane of the paper in the Figures. This implies that, when the lamellae 13 have, for example, assumed the position according to Fig. 1, the liquid flow may only pass in the gap formed in the longitudinal direction between each respective lamella 13 and the one wall of the container 14.

The lamellae 13 are connected to drive means 12 which are disposed to pivot or rotate the lamellae 13 between two extreme positions about a neutral position in which the lamella panels make a substantially equal angles with the vertical plane. In the one extreme position, the one lamella panel 15a lies against the wall of the container 14, and in the other extreme position, the other lamellae panel 15b lies against the opposing wall of the container 14. The lamellae 13 may assume any posi- tion whatever between these two extreme positions. As a rule, in the extreme positions the lamellae are rotated through approx. 15° from the neutral position.

When the liquid flow has passed all lamellae 13 and particles have settled on the lamella panels 15a,b, the supernatant runs via the out¬ let 10 to an outlet pipe 3. The particles which have settled on the la¬ mella panels 15a,b slide down along the panels and are accumulated in those pockets 5 which are formed between the wall 17 of the container and the lamella panels 15a,b abutting against the wall. Hereinafter, these pockets will generally be designated lamella sludge pockets 5. The position of the lamella sludge pockets 5 is thus determined by that extreme position each individual lamella 13 assumes.

Depending upon the different positions of the lamellae 13, the spaces between adjacent lamella panels 15a,15b will alternatingly function as countercurrent chamber 2 and concurrent chamber 4. On switching of the positions of the lamellae 13, the space between two adjacent lamella panels is changed from, for example, having been a countercurrent cham¬ ber 2 to being a concurrent chamber 4. On the upper side of each respective lamella panel 15a,b the settled particles are generally moved always in the same direction, irrespective of whether the rel- evant space at that time functions as a concurrent chamber 4 or as countercurrent chamber 2, while the direction of flow of the liquid varies. Because the flow direction of the liquid changes, the risk is reduced that settled material stays and becomes attached to the lamel¬ lae 13, a factor which greatly improves the function of the separator and lengthens the interval between cleaning operations.

The embodiment in which the lamella panels are elastically resilient enjoys the advantage that the demand on tolerances in manufacture is reduced, at the same time as a substantially tight abutment against the wall 17 of the container is obtained, whereby the sediment which is ac¬ cumulated in the lamella pockets 5 which the lamella panels form does not leak out from the pockets. The employment of elastically resilient lamellae also makes it possible, in certain embodiments, to use con¬ tainers of a substantially circular cross section. The configurational change of the lamella panels when they are moved to or from their ex¬ treme positions also implies that sediment which might possibly adhere to the panels is released from them. This, in combination with the fact that the flow direction of the liquid alternates in the spaces between the lamellae eliminates the risk that the lamellae 13 are blocked by adhering sediment, and so the separator becomes substantially self- cleaning. The cross section between the lamella panels 15a,b, i.e. the flow area, is greater in the countercurrent chambers 2 than in the concurrent chambers 4. The flow rate will hereby be lower in countercurrent separation than in concurrent separation. This may also be expressed such that the angle of the lamella panels 15a,b in relation to the liquid surface 11 is greater in the countercurrent chambers 2 than in the concurrent chambers 4 for those lamellae which form the lower defi¬ nition of each respective chamber. Both the switching of the flow rates and the change in inclination of the lamella panels contribute in the efficiency of the apparatus.

The angle between the lamella panels 15a,b and the liquid surface varies between approx. 30°, preferably 35° and approx. 60°, preferably approx. 50°. The smaller angle (approx. 30° or 35°) relates to a situ- ation when the lamella panels 15a,b constitute the lower region of a concurrent chamber 4 and the larger angle (approx. 60° or 50°) relate to the situation when the lamella panels 15a,b constitute the lower region of a countercurrent chamber 2. In the emptying position, the angle lies between 35° and 50°.

One example of an operational cycle for the separator with those embodiments which have been shown and described with reference to Figs. 1-5 will now be elaborated on.

Liquid carrying sludge which is fed into the container 14 {cf . Fig. 1) via the inlet 9 is forced, in a first stage, around the fixed spreader 8 which prevents vertical liquid flow. This continues past the edges 16 of the spreader and, once a portion of the flow has passed above the spreader, the flow continues upwards and in between the two lowermost, movable lamellae 13. In Fig. 1, these are shown in positions such that the space between the two first lamella panels 15a which the liquid flow meets forms a countercurrent chamber 2. Sludge which is separated in this space settles towards the lamella panel 15a of the first lamella and then slides down along the lamella panel 15b in order, at least in part, to be accumulated in the bottom sludge pocket 6. When the liquid flow has passed the tip (upper edge) of the first lamella, it passes into a concurrent chamber 4. Since the distance between the lamella panels 15a,15b is less in this space 4, the flow rate increases. Sludge which is separated in the space sinks down to contact against the lamella panel 15b of the lowermost lamella and then slides along this panel down into the lamella sludge pocket 5 which the lowermost lamella panel forms with the wall 17 of the container.

The liquid flow thereafter continues around the edge 25 of the second lamella panel and through the passage 19 into a countercurrent chamber 2 formed between the second and third movable lamellae 13 (counting from below). The sediment which is formed against the lamella panel 15b of the second lamella slides off the panel and generally sinks down to the sludge pocket 5 disclosed in the preceding paragraph. The size of the passage 19, and thereby the flow rate of the liquid is selected generally such that the particles go through the passage 19 and there¬ after sink down to the lamella sludge pocket 5. The flow then continues over the upper edge of the second lamella to a concurrent flow space 4 where sludge is accumulated in a second lamella sludge pocket 5.

The liquid flow continues alternatingly to pass countercurrent flow chambers 2 and concurrent flow chambers 4. The number of lamellae 13 which are provided in each individual case, and thereby the number of concurrent and countercurrent flow spaces which are passed will above all depend upon the nature of the sludge and the desired degree of separation.

Fig. 2 shows step two of the operational cycle. Prior to the switching of the lamellae to the positions illustrated in the Figure, the inflow of liquid containing dispersed particles is discontinued. On switching to the neutral position, the lamella sludge pockets 5 are opened and the sediment sinks from these along the walls 17 of the container down to the bottom sludge pocket 6. Because the inflow of liquid to the con¬ tainer has ceased, there will be no liquid flow which disturbs the movement of the sediment to the bottom sludge pocket. In stage 3 (Fig. 3), the lamellae are switched from the neutral posi¬ tion to their second extreme positions, i.e. the lamella panels 15a,b which were not in contact with the wall of the container 4 in stage 1 now abut against the wall of the container 14. The liquid flow through the inlet 9 is thereafter turned on. The different spaces or chambers between adjacent lamella panels 15a,b have now changed function from having been concurrent flow chambers 4 to being countercurrent flow chambers 2, and vice versa.

In the final stage, stage 4 (Fig. 4), the inflow of liquid containing dispersed particles is once again discontinued. The lamellae are set in the neutral position, whereby the lamella sludge pockets 5 are opened and the sediment sinks to the bottom sludge pocket 6.

Thereafter, the bottom valve is opened and the particles from the secondary sludge pocket 6 are removed from the container 14 via the sludge outlet 7. Depending upon the quantity of sludge which has been accumulated during the first stage, the bottom valve may also be opened in stage two in accordance with the above. In other applications, the separator is allowed to pass stages 1-4 several times before the bottom sludge pocket is emptied of its contents.

Reference numeral 11 relates in the Figures to the position of the liquid level in the container 14 during the different stages in accord- ance with the foregoing description.

In one alternative embodiment, each individual lamella panel 15a,b in the lamellae 13 is rotary.

In a further alternative embodiment, the lowermost, movable lamella constitutes the means 8 which form the spreader 8.

In still a further alternative embodiment, stage 3 is not employed, i.e. the lamellae 13 return to the earlier position, this giving a simpler regulation of the driving operation. One drawback in this embodiment is, however, that the separator will not be self-cleaning in that the individual spaces between the lamella panels 13 do not switch between being concurrent and countercurrent flow chambers.

Fig. 6 shows one embodiment of the apparatus in which the lamellae 13 are immobile, in other words have spatially fixed positions. The lamel¬ lae are sealingly connected to both of the opposing walls 27 which interconnect the walls 17 which are provided with oblique lines in the Figures. The opposing edges 25 of the lamellae are disposed a distance from the opposing walls 17 of the container. A number of mechanical closure devices 28 are placed on carriers 29 whose displacement is realized by drive means 12a.

Fig. 6 shows the apparatus provided with four lamellae 13. The drive means 12a have moved the right-hand carrier 29 in the Figure downwards, while the left-hand carrier has been moved upwards. The closure devices of the right-hand carrier are thereby set such that two of the passages between the wall 17 and the lamellae 13 are closed, namely (counting upwards from beneath) that at the second lamella and that at the fourth lamella. The closure devices of the left-hand carrier are set such that the passages at the first lamella and the third lamella are closed. There will hereby be formed between the lamellae spaces which are dis¬ posed in series in flow terms through which the liquid passes.

When the drive means have set the left-hand carrier in the lower posi- tion and the right-hand carrier in the upper position, the closure de¬ vices of the left-hand carrier are set such that the passages at the second and the fourth lamellae are closed, and the closure devices of the right-hand carrier are set such that the passages at the first and third lamellae are closed. In the placing of closure devices disclosed in this paragraph, the flow direction is opposed to that which is ob¬ tained in the placing of the closure devices as disclosed in the pre¬ ceding paragraph.

After a certain time, the closure devices 28 are turned by drive means (not shown in the Figure) to an orientation where they are substan¬ tially parallel with the wall of the container. In such instance, the lamella sludge pockets 5 are opened and the sediment sinks to the bot¬ tom sludge pocket 6.

Figs. 7a and 7b show one embodiment in which the lamellae are substan- tially planar. The lamellae are disposed to be displaced while retain¬ ing their orientation substantially horizontally in the container 14. Every second lamella is interconnected with a displacement device (not shown in the Drawings) in order to form a composite system of lamellae which are displaced simultaneously. In Fig. 7a, the first, the third, the fifth and the seventh lamellae (counting upwards from beneath) have been moved to the right, and the second, the fourth and the sixth la¬ mellae have been moved to the left. There will hereby be formed at the first, third, fifth and seventh lamellae a passage 19 adjacent the left-hand wall 17 of the container. At the second, fourth and sixth la- ellae there will be formed a passage 19 between the lamellae and the right-hand wall 17 of the container. There will hereby be formed be¬ tween the lamellae spaces which are disposed in series in flow terms through which the liquid passes (cf. Fig. 7a).

By moving the first, third, fifth and seventh lamellae to the left and the second, fourth and sixth lamellae to the right, there will cor¬ respondingly be formed spaces which are disposed in series between the lamellae in terms of flow and through which the liquid passes (cf. Fig.

7b). With the placing of the lamellae disclosed in this paragraph, the flow direction is opposed to the flow direction in the lamella placing disclosed in the preceding paragraph.

By varying the distance between mutually adjacent lamellae, the flow area is, in certain embodiments, adapted for those spaces which are formed between the lamellae so that, for example, the flow area is greater in countercurrent sedimentation than in concurrent sedi¬ mentation.

By moving the lamellae so that they are located in an intermediate po- sition (cf. Fig. 7c), all lamella sludge pockets 5 are opened and the sediment sinks to the bottom sludge pocket 6. In certain practical applications of the invention, the supernatant is recycled to the separator for an additional sedimentation process. This is an alternative to increasing the number of lamellae 13.

The foregoing description has referred to but a limited number of em¬ bodiments. However, a person skilled in the art will readily perceive that the present invention encompasses a large number of embodiments without departing from the spirit and scope of the appended claims.

Claims

1. An apparatus for separating particles from liquid or for separating liquids of different densities from one another by sedimentation, comprising a container (14), said container (14) including an inlet (9) for liquid containing the particles, or one or more inlets (9) for liquids of different densities, an outlet (10) for supernatant, and an outlet (7) for sedimented sludge or settled liquid, where the inlet (9) and the outlet (7) for sludge or liquid are disposed in the lower region of the container (14), and the outlet (10) for supernatant is disposed in the upper region of the container (14), and where two or more lamellae (13) are superposed over one another in the container (14) between the outlet (10) for supernatant and the inlet (9) for the mixture of liquids or for liquid containing particles, c h a r a c t e r i z e d in that the lamellae (13) form between them a number of spaces which are disposed in series in flow terms and which alternatingly form concurrent flow chambers (4) or countercurrent flow chambers (2).

2. The apparatus as claimed in Claim 1, c h a r a c t e r i z e d in that each lamella is disposed alternatingly with its opposing end regions/end edges (25), to substantially sealingly connect to op¬ posed walls (17) in the container (14) either directly or via a mechanical closure device.

3. The apparatus as claimed in Claim 1 or 2, c h a r a c t e r ¬ i z e d in that drive means (12) are provided for rotating the lamellae (13) to positions where they alternatingly assume posi¬ tions in which first the one edge/edge region (25) of the lamellae and thereafter the other edge/edge region of the lamellae substan¬ tially sealingly connect to opposing walls (17) in the container (14), or where they assume positions in which there are formed, between the lamellae (13) and the opposing walls (17), passages (19) for emptying accumulated sludge or settled liquid.

The apparatus as claimed in any of the preceding Claims, c h a r a c t e r i z e d in that each lamella (13) comprises two lamella panels (15a,b) disposed at an angle to one another for forming a roof-like lamella with the angle apex of the lamella directed upwards.

5. The apparatus as claimed in any of the preceding Claims, c h a r a c t e r i z e d in that the inlet (9) is directed up¬ wardly towards the underside of a roof-shaped disc (8) which is disposed over the inlet (9) for disrupting the vertical liquid flow from the inlet (9); and that the lower edges of the roof-shaped disc are each located on a level below the level of the mouth of the inlet.

6. The apparatus as claimed in any of the preceding Claims, c h a r a c t e r i z e d in that a pocket (6) for sedimented sludge or sedimented liquid is formed in the bottom of the con¬ tainer; and that pockets (5) for temporary collection of sedimented sludge or sedimented liquid are formed between the wall of the con¬ tainer (14) and that end portion of the lamella which abuts against the wall, the pockets (5) for temporary collection being opened when the lamellae (13) are pivoted to assume an emptying position.

7. The apparatus as claimed in Claim 6, c h a r a c t e r i z e d in that the outlet (7) is connected to the pocket (6) in the bottom of the container; and that a valve is disposed in connection with the outlet (7) for emptying sedimented sludge or settled liquid from the pocket (6) in the bottom of the container.

8. The apparatus as claimed in any of the preceding Claims, c h a r a c t e r i z e d in that the lamellae (13) alternatingly form concurrent flow spaces (4) and countercurrent flow spaces (2) for the liquid containing particles or the mixture of liquids; and that the concurrent and countercurrent flow spaces (2,4) are con¬ nected in series in flow terms when the lamellae abut against the wall in the container; and that said spaces (2,3) assume parallel- connected positions when the lamellae (13) assume the emptying po¬ sition.

9. The apparatus as claimed in Claim 8, c h a r a c t e r i z e d in that the distance between adjacent lamellae (13) is less in the concurrent flow spaces (4) than in the countercurrent flow spaces (2).

10. The apparatus as claimed in any of the preceding Claims, c h a r a c t e r i z e d in that the angle between the horizontal plane and that lamella panel (15a,b) which abuts against the wall of the container (14) is at least approx. 30°, preferably approx. 35°; and that the angle between the horizontal plane and the la¬ mella panels (15a,b) is between 40° and 45° at the emptying posi¬ tion of the lamellae.

11. A method for separating particles from liquid or for separating liquids of different densities from one another by sedimentation in a sedimentation container (14) from which container (14) particles or sedimented liquid and supernatant, respectively, are discharged in separate outlets (7,10), c h a r a c t e r i z e d in that in¬ coming liquid in the container (14) is caused to pass a number of spaces which are disposed in series in flow terms and which alter¬ natingly act as concurrent flow chambers (4) and countercurrent flow chambers (2) .