IE47097B1

IE47097B1 - Apparatus for separating a discontinuous phase from a continuous phase

Info

Publication number: IE47097B1
Application number: IE1232/78A
Authority: IE
Original assignee: Paterson Candy Int
Priority date: 1978-01-27
Filing date: 1978-06-19
Publication date: 1983-12-14
Also published as: IE781232L; GB1585141A; AU3950378A; AU524263B2; ZA783969B

Description

The present invention relates to apparatus for separating a discontinuous phase moving under gravity or gravitational buoyancy from a continuous phase.

The invention provides apparatus for separating a discontinuous phase from a continuous phase, comprising a plurality of parallel inclined plates wherein the underside of each plate is provided with a transversely extending inverted channel shaped trap which projects from the underside of its respective plate into a passage defined between the general planes of its respective plate and an adjacent plate for receiving discontinuous phase rising in use between the plates and/or the topside of each plate is provided with a transversely extending upright channel shaped trap which projects from the topside of its respective plate into a passage defined between the general planes of its respective plate and an adjacent plate for receiving discontinuous phase falling in use between the plates.

Preferably, the traps are substantially V-shaped. Preferably, the side of each trap remote from the respective plate has an extension such that the height of the extension edge to the V base is greater than the perpendicular distance between adjacent plates. Preferably, each extension is substantially parallel to its respective plate. - 2 4 7097 Preferably, the parallel plates overlap vertically so that the lower or upper edge of each plate comes forward of the upper or lower edge respectively of the extension of the trap on the adjacent plate by an angle of at least 10° to the vertical.

The traps may extend horizontally or be inclined to encourage flow of the separated discontinuous phase transversely of the plates.

Thus, the apparatus is suitable, for example, for collecting gases rising in swarms of bubbles in otherwise open tanks or where an aerated volume is to be incorporated underneath an unaerated volume or where the gas is to be collected for further use. The apparatus is also suitable for the separation of two liquids for example where a continuous aqueous phase is to be extracted from a low density inflammable organic solvent in an open tank.

The apparatus is most suited to large rectangular tanks such as are used for the aeration of effluents in the course of biological purification. (5 But it can equally be applied to other processes where two fluids are to be separated particularly where it is desired to have an exposed surface to the continuous phase.

The invention will now be described with reference to embodiments shown by way of example in the accompanying drawings, wherein: Fig. 1 is a vertical· section of a tank containing apparatus according to the invention, Fig. 2 is a front view of the apparatus of Fig. 1, Fig. 3 is a view similar to Fig. 2 of a modified apparatus, Fig. 4 is a diagrammatic side view of alternative apparatus according to the invention, and Fig. 5 is a diagrammatic side view of further alternative apparatus according to the invention.

In Fig. 1 a tank 1 contains apparatus for separating a discontinuous phase from a continuous phase (e.g. air from water). The apparatus comprises a - 3 4 plurality of parallel inclined plates 2. The top of each plate 2 is bent downwards so as to form on the underside of each plate a transversely extending inverted channel shaped trap 3 having the shape of an inverted V, although any other suitably-shaped transversely extending inverted channel-shaped trap may be used.

The lower edge of each channel-shaped trap 3 preferably has a downwards extension 4 extending substantially parallel to or converging with the adjacent plate 2. The shape of the channel-shaped trap 3 and the extension 4 is not critical. However, the angle Θ between the lower edge 5 of the adjacent plate 2' and the lower edge 6 of the extension 4 is preferably at least 10° to the vertical so as to ensure sufficient overlap thereby ensuring that the discontinued rising phase, i.e. bubbles 7 rising through liquid 8, are caught by the channel-shaped traps 3.

The tank 1 has one or more inlets (not shown) below the plates 2 and an outlet 9 for separated liquid 10 below the level 11 of the liquid. As can be seen from Fig. 2 side plates 12, which are preferably notched, house the inclined plates 2 and maintain separation of the two phase zone, in this embodiment liquid and gas 13, from the single phase zone, in this embodiment separated liquid 10.

The operation of the apparatus is partly self evident. The discontinuous phase is trapped by the inclined plates and rises into the traps 3 where it collects and flows in a lateral direction, allowing the continuous phase to proceed separately. However, with a coarse discontinuous phase conditions are turbulent and a horizontal vortex forms in the trap so that there tends to be some overshoot leading to the escape of some of the dispersed phase. This is prevented by the deep overhang of the extension 4.

By way of example, plates 500 mni. long inclined at 60°, separated horizontally by 200 mm. gave complete separation of air from water in a diffused air activated sludge tank.

The embodiment of Fig. 3 is similar to that of Figs. 1 and 2 except that inverted collecting channels or ducts 14 are provided to remove the separated discontinuous phase 13, e.g. for recirculation via a controlled level vent tower 15. - 4 4 7 0 9 7 In particular, the apparatus finds application in three phase separations where air is being used to agitate or aerate a solid/1iquid suspension where at the same time the solid phase is to be retained in the system. The apparatus removes the air from the system thereby enabling the solids to settle back into the aerated zone and a clear liquid to be discharged, e.g., as in the cleaning of a sand filter media by combined air scour and water wash. Likewise in the contacting of activated sludge for example, with enriched oxygen, the residual oxygen may be collected and reinjected in another stage of treatment without the expense of a gas tight cover.

The apparatus may also be extended or incorporated into a laminar flow inclined plate separator system (Fig. 4) by extending the main inclined surface of the plates 2 upwards or downwards. In such a way an extended surface for solid/1iquid separation may be combined with gas/liquid separation.

The above described embodiments may be modified to separate a falling discontinuous phase e.g. a dense liquid from a liquid. In this case the channelshaped traps are formed at the lower top side of the plates, and are not inverted (see the bottom of the plates in Fig. 5). Any particular orientation described above will also apply in a similar way when the discontinuous phase falls rather than rises.

For the separation of three fluid phases both inverted traps 3 and upright traps 16 may be combined in a single assembly (Fig. 5).

Claims

1. Apparatus for separating a discontinuous phase from a continuous phase, comprising a plurality of parallel inclined plates wherein the underside of each plate is provided with a transversely extending inverted channel-shaped trap which projects from the underside of its respective plate into a passage defined between the general planes of its respective plate and an adjacent plate for receiving discontinuous phase rising in use between the plates and/or the topside of each plate is provided with a transversely extending upright channelshaped trap which projects from the topside of its respective plate into a passage defined between the general planes of its respective plate and an adjacent plate for receiving discontinuous phase falling in use between the plates.

2. Apparatus as claimed in Claim 1, wherein said traps are substantially V-shaped.

3. Apparatus as claimed in Claim 2, wherein the side of each trap remote from the respective plate has an extension such that the height of the extension edge to the V base is greater than the perpendicular distance between adjacent plates.

4. Apparatus as claimed in Claim 3, wherein each extension is substantially parallel to its respective plate.

5. Apparatus as claimed in Claim 3 or Claim 4, wherein the lower or upper edge of each plate comes forward of the upper or lower edge respectively of the extension of the trap on the adjacent plate by an angle of at least 10° to the vertical.

6. Apparatus as claimed in any one of the preceding claims, wherein the traps extend horizontally.

7. Apparatus as claimed in any one of Claims 1-5 wherein the traps are inclined with respect to the horizontal to encourage flow of the separated discontinuous phase transversely of the plates. - 6 >4.7 0 97

8. Apparatus as claimed in any one of the preceding claims, wherein the inclined plates are mounted in an open tank.

9. Apparatus for separating a discontinuous phase from a continuous phase, substantially as herein described with reference to Figures 1 and 2, 5 3, 4 or 5 of the accompanying drawings.