GB2116061A - Plate separator - Google Patents

Abstract

A plate separator comprises parallel, corrugated and transversely inclined plates 1 between which liquid flows from an inlet chamber 4 to an outlet chamber (not shown) while heavy or light impurities settle into spaces 2 and 3. Means are provided in chamber 4 to ensure equal flows into the various passages between the plates. In Figure 3 this means comprises a grid 12 made up of horizontal tubes and a baffle 14 with vertical slots. The grid and baffle are both rendered imperforate at a central region aligned with the vertical plane where two groups of oppositely inclined plates 1 meet. In Figure 2 equal flows are ensured by arranging the inlet edges of plates 1 on an inclined plane, with further assistance provided by adjustable baffles (11). <IMAGE>

Description

SPECIFICATION A plate liquid separator In plate separators the supply of the liquid to be treated often takes place in the vertical direction, viz.

from a supply chamber communicating with superposed passages between the plates of the separator proper, the liquid supply opening into said chamber at the lower or upper end thereof.

In the case of a parallel4low separator with inclined plates, such a supply chamber often also serves as a collecting space for separated components leaving the separation passages, the dimensions of this chamber as seen in the longitudinal direction of the plate assembly then being sufficiently large for bringing about a gradual deflection of the liquid flow towards the inlet end of the plate assembly, and this in such a manner that the supply flow will be evenly distributed over the passages. If the supply chamber also serves as a collection chamber for separated components, guiding baffles or channels are generally provided for keeping the separated components leaving the plate assembly separated from the supply flow, which baffles or the like promote a uniform flow distribution.

On the other hand, so-called cross-flow separators exist which also comprise inclined plate assemblies, the slope thereof, however, being directed trans tersely to the flow direction of the liquid, so that components separated between the plates can be collected laterally of the flow passages. The supply chamber of such a separator serves, then, no longer for collecting separated components, and can, there- fore, have a smaller dimension as seen in the longitudinal direction, so that the over-all dimension of the separation device is reduced. The mainly vertically directed liquid flow in this chamber should, then, be deflected towards the passages of the plate assembly.

It has now appeared that particularly in such narrow supply chambers the distribution of the liquid flow over the height of the plate assembly becomes irregular, so that a non-uniform loading of the various separation passages will occur which unfavourably influences the separation effect.

The invention envisages to improve the supply in such a supply chamber in such a manner that a more uniform loading of the passages of the plate assembly is obtained.

To that end the plate separator according to the invention is characterised by flow distributing means in the supply chamber extending at an upward or downward slope respectively from the rearward boundary wall of the supply chamber joining the lower or upper end respectively of the plate assembly towards the forward boundary wall of this chamber, and thereby such a flow distribution is obtained that the passages of the plate assembly will be substantially evenly loaded.

In a first embodiment of the separator according to the invention, the plates of the separation assembly are arranged in such a manner that the boundary plane of the inlet side of this assembly extends at a slope between the forward and rearward boundary wall of the supply chamber, and then the plates themselves will bring about the deflection of the liquid flow.

In a second embodiment of the separator according to the invention with a usual straight plate assembly, the distribution means are formed by a grid with substantially horizontal grid rods extending at a slope between the rearward and forward boundary walls of the supply chamber, said grid rods being situated, in particular, in a curved plane having its convex side directed towards the inlet end of the plate assembly.

In orderto obtain a good influencing of the flow, preferably grid rods are used which have a width that is larger than the width of the passage between the rods. These grod rods will preferably be formed by tubes which, on the one hand, allows to reduce the weight accordingly, and, on the other hand, the round cross-sectional shape of the tubes has a favourable influence on the flow.

In plate assemblies having a larger width it can be favourable to use two or more supply connections which are mutually separated in the lateral direction of the assembly. Although a better lateral flow distribution can be obtained thereby, nevertheless the supply towards the centre of the supply chamber may be stronger. According to the invention, a partition plate can be arranged in the grid substantially half-way between two adjacent connections, by means of which the flow will be sufficiently decelerated in its vicinity for improving the flow distribution there. In particular such a plate consists of a flexible strip which has been woven alternately above and below adjacent grid rods or tubes through the grid.

The distribution along the width of the plate assembly can be improved still further by arranging an additional grid substantially parallel to the inlet surface of the plate assembly, the rods thereof being directed substantially transversely to the plates of the assembly, and in particular substantially vertically, which grids can again be assembled from tubes.

If the plate assembly consists of two or more sub-assem blies with an opposite slope of the plates, between which a collecting duct for components separated between the plates is situated, which duct is shielded at the inlet side against liquid flowing in, it can be advisable to arrange an additional grid near this shield so as to avoid undesired turbulences at the inlet side of the plate assembly.

In both embodiments it can be favourable to provide, at the inflow side of the supply chamber, additional guiding grids which, in particular, consist of pivotable plates, so as to allow to influence the flow distribution still further and to adapt it to variable conditions.

The invention will be elucidated below in more detail by reference to a drawing, showing in: Figure Z a highly simplified diagrammatic section of the inlet portion of a cross-flow separator of current design; Figure2 a still more simplified diagrammatic section of the inlet portion of a first embodiment of the separator according to the invention; Figure 3 a simplified section corresponding to Figure 2 of a second embodiment of the separator of the invention; and Figures 4 and5 sections on the lines IV - IV and V V resp. of Figure 3.

In Figure 1 a diagrammatic vertical section ofthe inlet side of a current cross-flow separator is shown.

The latter comprises a plate assembly 1 consisting of superposed and in particular corrugated plates, not shown, with intermediate separation passages, which plates have a slope in respect of the vertical plane, and a liquid flow can flow substantially horizontally through the passages, and the components separated therefrom can slide away trans tersely to the liquid flow. These components are, then, collected in a collecting chamber 2 for heavy components and/or in a collecting chamber 3 for light ones.

The liquid enters the passages of the assembly 1 from a supply chamber4which is defined by a rear wall 5 with an opening 6 joining the assembly 1, and a afront wall 7 provided with a supply opening 8 which, in the case shown, is situated at the lower side. This opening is, for instance, delimited by a conical bottom 9, and, on the other hand, the wall 7 delimits a coalescence passage 10 in which the supply flow is directed downwardly. Reference can be made to the prior patent application. Of course the opening 8 can also directly connect to a supply duct.

The flow rising in the chamber 4 is to be distributed over the inlet opening 6 of the assembly 1, and is, then, to be diverted by an angle of 900. As a consequence of the relatively small distance between the walls 6 and 7, it has appeared in practice that this distribution will not be uniform, a consequence thereof being that the various passages between the plates of the assembly 1 are unevenly loaded so that the separation effect will be unfavourably influenced.

The same will occur when the opening 8 is situated at the upper side, and the liquid flow in the chamber4 is directed downwardly. For the sake of simplicity an upward flow will always be assumed in the following description.

Figure 2 shows a first embodiment of an improved separator according to the invention, in which a more uniform flow distribution can be obtained.

Therein the plates of the assembly 1 are shaped so that the inlet opening 6 extends obliquely between the walls 5 and 7. Thus the plates themselves bring about a deviation of the flow allowing to obtain a substantially uniform flow distribution over the inlet side of the assembly 1. If required the flow in the cross-section of the chamber 4 can be additionally influenced by arranging, near the opening 8, guiding baffles 11 which, in particular, can be made adjustable.

The embodiment of Figure 2 requires, however, specially shaped, and in particular lozenge shaped plates, which can sometimes be objectionable, and, moreover, such a solution is not possible in an existing separator according to Figure 1, Figure 3 shows a different solution according to the invention which is suitable for being used in a separator of current design.

Therein a grid is arranged at the inflow side of the chamber 4, consisting of a plurality of substantially horizontally directed rods 12, the latter being situated in a plane extending obliquely from the wall 5 upwards to the wall 7. Preferably rods are used with a relatively large diameter, the latter being, in particular, larger than the distance between adjacent rods. It is, then, favourable to use hollow tubes as said rods so as to reduce the weight thereof accordingly, and, moreover, use can be made of commercially available tubes.

It has appeared that such a grid can bring about such a flow distribution that the flow is evenly distributed over the opening 6. The best results appear to be obtained when the plane of the grid is slightly upwardly curved, and a circular curvature appears to be sufficient. The most favourable values of the slope and curvature depend on the other dimensions, but can, in practice, easily be determined experimentally.

In practice the conical bottom 9 below the opening 8 will often be made double-conically as shown at 9' and Sin Figure 4, so as to obtain a better flow distribution in the lateral direction. It can be advisable then to close the grid completely over a small width about half-way between the bottom halves 9' and 9", as shown at 13 in Figure 4, so as to reduce the flow rate additonally in the central part. This can, for instance, be done by weaving a strip of flexible material alternately above and below the rods or tubes through the grid.

A further improvement of the flow distribution in the lateral direction of the opening 6 can be obtained by arranging an additional grid 14 at a small distance before the opening 6, consisting of substantially vertical rods or tubes 15 as shown in Figure 5. For the rest, such a grid can also be provided in the case of Figure 2, but then the grid should be given a slope adapted to the bevel of the plate assembly 1.

If the assembly 1 consists of two juxtaposed subassemblies 1' and "with a mirror-symmetrical arrangement of the plates, as diagrammatically shown in Figure 5, it can be advisable to arrange, in the central part of the grid 14, a baffle 16 which is situated in front of the junction between both subassemblies 1' and 1". Thisjunctin is generally formed by a discharge chamberfor components separated in the subassemblies, which chamber extends in the longitudinal direction of the assembly 1 and communicates with the collecting spaces 2 and/or 3 and is closed at the front side. The baffle 16 forms an additional shield adapted to suppress undesired turbulances in that region.

Claims (12)

1. A plate separator, comprising an assembly of superposed substantially parallel and in particular corrugated plates, between which separation passages are situated through which a liquid to be treated can be led, said plates being arranged at a slope so that components separated in said passages from the liquid led through can slide off along said plates towards a collecting space, which passages connect, at one extremity, to a supply chamber for the liquid to be treated, and, at the other extremity to a discharge chamber for the treated liquid, a liquid supply connection opening into the supply chamber at either the upper or the lower end, all this in such a manner that, in said chamber, a substantially vertical flow can be generated which can divert towards the passages between the plates, characterised by flow distribution means in said supply chamber (4) extending at an upward or downward slope resp. from the rearward boundary wall (5) of the supply chamber (4) joining the lower or upper end resp. of the plate assembly (1) towards the forward boundary wall (7) of said chamber (4), such a flow distribution being obtained thereby that the passages of the plate assembly (1 ) will be substantially evenly loaded.

2. The separator of claim 1, characterised in that the boundary plane (6) of the inlet side of the plate assembly (1 ) extends at a slope between the forward (7) and rearward (5) boundary wall of the supply chamber (4).

3. The separator of claim 1, characterised in that the distribution means comprise a grid with substan tially horizontal grid rods (12).

4. The separator of claim 3, characterised in that the grid rods (12) are situated on a curved plane having its convex side directed towards the inlet (6) of the plate assembly (1).

5. The separator of claim 3 or 4, characterised in that the grid rods (12) have a width which is larger than the width of the passages between said rods.

6. The separator of any one of claims 3..5, characterised in that the grid rods (12) consist of tubes.

7. The separator of any one of claims 3..6, having two or more supply connections which are mutually separated in the lateral direction of the supply chamber, characterised by a separating baffle (13) situated substantially mid-way between two adja cent supply connections (9', 9"), said baffle (13) extending between the forward and rearward walls (7, 5) of the supply chamber (4) and increasing the flow resistance in the region between both connec tions (9', 9").

8. The separator of claim 7, characterised in that the separating baffle (13) is a part of the grid (12).

9. The separator of any one of claims 1..8, characterised by an additional flow distributing grid (14) which is situated substantially parallel to the inlet surface (6) of the plate assembly (1), the grid rods (15) thereof being directed substantially trans versely to the plates in the assembly (1).

10. The separator of claim 9, characterised in that the additional grid (14) consists of tubes.

11. The separator of claim 9 or 10, in which the plate assembly constitutes a cross-flow separator consisting of juxtaposed subassemblies with alter nately opposite slopes, characterised in that in front of the junction between two subassemblies (1', 1") the grid (14) is provided with a cover plate (16).

12. The separator of any one of claims 1..11, characterised in that, in the supply chamber (4), an additional guiding grid (11) consisting of pivotable plates is arranged.