SEPARATORS

Abstract: A separator comprises an assembly of a first vessel (6) and an upwardly-oriented elongate unit (8) including a helical baffle (12) forming a spiral passage (14) in said unit (8). The first vessel (6) has a sump (11) and the unit (8) is in fluid communication with the first vessel (6). An inlet means is provided to convey a mixture to be separated into the assembly, and at least two outlet means are provided through which the separated components of the mixture are removable from the assembly, the mixture passing through the first vessel (6) and the passage (14) of the unit (8) with a disposable component being discharged and a required residual component being held in the first vessel (6).

Description: SEPARATORS This invention relates to separators for separation of liquids from mixtures of liquids having different specific gravities, or for separation of liquids and solids from mixtures of liquids and solids. The technology of separation is complex and involves factors which affect the efficiency of separation including differences in specific gravity (density for * short), surface chemistry, flow characteristics, temperature, time and desiyn of the containing vessels. In practice, layers of material in a vessel will tend over a time period to stratify according to density, the most dense lying at the bottom and the least dense at the top. The smaller the differences in density, the longer it will take for efficient separation to occur. Separators are designed in such a way as to:- a) provide time for settling to occur; b) avoid excessive intermixing between different layers especially duriny the entry and exiting of materials; and c) facilitate the easy removal of separated materials. Traditional separators such as those used in industry tend to be bulky in order to allow time for settling to occur. Many contain a series of chambers to quieten flow and to achieve a degree of separation before passing material on to subsequent stages. Problems often occur due to carry-over of unwanted materials.. For instance, solid debris tends to be present at the outflow from septic tanks, leading to excessively high biological oxygen demand in the effluent and to eventual clogging of drainage channels. -Separators, called interceptors, which are used to separate petrol and oil from surface water drainage installations on garage forecourts can also become inefficient due to intermixing at high flow-rates, such as ma/ occur in flash floods. This can result in excessive carry-over of unwanted materials into a mains drainage system. In addition to the above operational problems, conventional separators are often expensive in the use of materials of construction and labour in manufacture and installation, and take up a good deal of space in manufacture, transport and use. A large number of septic tanks are still constructed in situ using blocks and mortar. An object of the present invention is to obviate or mitig-ate these manufacturing and operational problems. Accordingly, the present invention is a separator comprising an assembly of a first vessel and an upwardly-orie ted elongate unit including a helical baffle forming a spiral passage in said unit, the first vessel having a sump and the unit being in fluid communication with the first vessel, an inlet means being provided to convey a mixture to be separated into the assembly, and at least two outlet means being provided through which the separated components ' of the mixture are removable from the assembly, the mixture passing throuyh the first vessel and the passage of the unit with a disposable component being discharged and a required residual component being held in the first vessel. Preferably, the unit comprises the baffle and is mounted inside the first vessel with the sump of the first vessel formed in the central portion thereof, the inner part of the baffle being cut-away adjacent to a bottom plate of the first vessel. First alternatively, the unit is a second vessel of smaller dimensions than the first vessel with the baffle therein and is provided upwardly-oriented in the first vessel and extending a predetermined distance thereinto with therebelow a lower part of the first vessel serving as a sump to hold the residual component The unit is preferably arranged to receive the mixture at the inlet end of the passage substantially centrally of the unit to flow around the passage with. the disposable component being discharged therefrom at therefrom at or adjacent to the end of the passage via a pipe through the first vessel, while the residual component flows into the sump of the first vessel. Alternatively, the unit may be arranged to receive a partially separated mixture, the mixture first having passed through the first vessel to perform an initial separation of the components, the disposable component of the mixture thereafter being discharged from the unit via piping through the first vessel. Further alternatively, the unit is preferably a second vessel with the baffle mounted therein, the unit beiny mounted above the first vessel, the inlet means passing through the unit to terminate below a bottom plate in the unit, an aperture being provided in said bottom plate at or adjacent to an inner end of the passage to allow flow from the first vessel into the inner end of the passage to be discharged adjacent to the top of . the unit at or adjacent to the outer end of the passage. Preferably also, the spiral passage has at least two concentric circling coils. An outer coil of the bottom end of the baffle is preferably apertured to allow flow between the part of the passage in the outer coil and the part of the passage in the next adjacent coil. Preferably further, the baffle is formed from coiled straight sheet. Alternatively, the baffle is formed from coiled corrugated sheet. Embodiments of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: - Fig. 1 is a perspective view of a separator according to a first embodiment of the present invention; Fig. 2 is a perspective view of a unit of a separator according to a second embodiment with part cut-away for clarity; Fig. 3 is a plan view of the separator shown in Fig .2 ; Fig. 4 is a perspective view of a separator accordiny to a third embodiment with part cut-away for clarity; Fiy. 5 is a plan view of the separator shown in Fig. 4; Fig. 6 is a perspective view of a separator according to a- fourth embodiment; Fig. 7 is a cross-sectional view of the separator alony line VII-VII of Fig. 6; Fig. 8 is a perspective view of a modification of the separator shown in Fig. 1 ; Fig. 9 is a vertical cross-sectional view of the separator shown in Figs. 2, 3 , 4 or 5 with a modified baffle; and Fig. 10 is a plan view of a unit of a separator with part of the baffle shown as corrugated. Referring to the drawings, a separator comprises- an assembly of a first vessel 6 and a unit 8 having an internal helical baffle 12 forming a spiral passage 14 extending the full height of the vessel 10. The spiral passage 14 has at least two concentric circling coils. Inlet means is provided to convey a mixture to be separated into the assembly and at least two outlet means are provided through which the separated components of the mixture are removable from the assembly. In a first embodiment as shown in Fig. 1, the unit 8 comprises baffle 12 inside the first vessel 6. The passage 14 has two circling coils with an inlet pipe 16 forming the inlet means and entering the first vessel 6 axially to pass into a sump 11 of the first vessel 6. The sump 11 is formed in the central position of the first vessel 6 with the lower part of the inner end of the baffle 12 being cut-away at 9 adjacent to a bottom plate of the first vessel 6. In use, the assembly is installed underground and is integrated into the system through which a mixture of water and solids, e.g. from a piped soild waste system, to be separated is fed through inlet pipe 16, ie. the inlet means. The bulk of the high density component i.e. solid wastes, remains in the sump 11 with the remainder of the higher density component being deposited on the floor of the passage 14 as the mixture passes therethrough with the disposable component, i.e. water being discharged throuyh an oulet 20. As the solid wastes, which are the required residual component dissolve, they are carried away in the water. In the remaining embodiments, the unit 8 comprises an upstanding elongate second vessel 10 of hollow ■ cylindrical shape having a side surround 10A, a bottom 10B and a top (not shown). The second vessel 10 has an internal baffle 12 forming a spiral passage 14 extending the full height of the second vessel 10. The spiral paεsaye 14 has at least two concentric coils. In a second embodiment as shown in Figs. 2 and 3 in which like parts are denoted by like numerals, the unit 8 is a second vessel 10 of smaller dimensions than the first vessel 6 with the baffle 12 therein and is provided upwardly-oriented in the first vessel 6. The second vessel 10 extends a predetermined distance thereinto with therebelow a lower part of the first vessel 6 serving as the sump 11 to hold the residual component. The unit 8 is arranged to receive the mixture at the inlet end of the passage 14 substantially centrally of the unit 8 to flow around the passage 14 with the disposable component being discharged therefrom at or adjacent to the end of the passage 14 via a pipe 15, ie. an outlet means, passing through the first vessel 6, while the residual component flows .through aperture 19 provided in the wall 10A of the second Vessel 10 into the sump 11 of the first vessel 6. In use, the assembly is installed underground and integrated into the system from which a mixture of liquids is to be fed. This embodiment is particularly to be fitted under a garage forecourt near petrol pumps and is to recover petrol or oil from a mixture of same with rainwater or other liquid combined therewith, such as may occur with flash spills of petrol. The disposable component is the water and the required residual component is the petrol or oil which is removed periodically through a second outlet trap provided in the top. Fig. 2 shows a ground surface 7, a grating 5 and a funnel 3 which feeds into the inlet pipe 16. In a third embodiment as shown in Figs. 4 and 5 in which like parts are denoted by like numerals, the unit 8 is similarly provided in the first vessel 6 as in the second embodiment. The unit 8 is arranged to receive a partially separated mixture, the mixture first having passed through the first vessel 6 to perform an initial separation of the components. The disposable component of the mixture thereafter is discharged from the unit 8 via piping 17 through the coils in the baffle 12 and the first vessel 6. The ' inlet means is a pipe 21 feeding into the first vessel 6. An upright aperture 23 is provided in the wall 1 OA of the second vessel 10 through which the partially separated mixture passes into the passaye 14. In use, the assembly is installed underground and integrated into a soil waste disposal system and operates as above described. In a fourth embodiment as shown in Figs. 6 and 7 in which like parts are denoted by like numerals, the assembly includes a unit 8 comprising a second vessel 10 with a baffle 12 mounted therein. The unit 8 is mounted above the first vessel 6 with the inlet means being a pipe 25 passing through the baffle 12 of the unit 8. The baffle 12 is of conical shape with its bottom edge secured to the wall 1 OA of the second vessel 10 as shown. The inner coil of the baffle 12 is cut-away as in the first embodiment. The outlet means is a pipe 27. A restriction plate 29 is provided across the passage 14 as shown, the plate 29 extending downwardly of the passage about two thirds of the distance and having a series of holes therein. In use, the assembly is also installed underground and integrated into the system, ie. a soil waste system, and is used in the same manner as for the previous embodiments. In a modification (not shown) of the fourth embodiment, the baffle 12 in the unit 8 is vertical and the pipe 25 extends through the baffle 12 and is cranked downwardly to terminate below a bottom plate in the unit 8, an aperture being provided in said bottom plate at or adjacent to an inner end of the passage 14 to allow flow from the first vessel 6 into the inner end of the passage 14 to be discharged adjacent to the top of the unit 8 at or adjacent to the outer end of the passage 14. In a modification of the first embodiment as ' shown in Fig. 9 in which like parts are denoted by like numerals, the bottom of the first vessel 6 is shaped as a funnel 31 , the outlet pipe 33 of which has a valve 35 through which the sump 11 can be drained. In common to all embodiments, an outer coil of the bottom end of the baffle 12 may be apertured at 18 to allow flow between the part of the passage 14 in the outer coil and the part of the passage 1 in the next adjacent coil. The apertures 18 are cut-outs extending upwardly from the bottom of the vessel 10 as shown in Figs. 8 and 9. In a modification, the aperture 19 in Fig. 2 may be in the form of a weir radially extending a short distance down from the top of the wall 12. In a second modification, the baffle 12 may be of inverted frusto-conical shape. The assembly may have flexible components provided in a collapsed state which are made rigid on erection such as for use in third world countries, or for emergency use. Separators are designed to work continuously and/or intermittently. The structure of the present separators is to improve the efficiency of separation when used in either or both of these regimes. When operating as a continuous flow separator, the structure maximises the period of time in which liquids and solids or a mixture of liquids of different density can separate and it minimises the effects of intermixing. This results in efficient separation and subsequent recovery from appropriate outlets. When operating intermittently (such as in domestic septic tanks), the structure features an additional advantage in that it utilises the periods of time when flow has ceased for separation to continue. In these quiet periods, liquid throughout the separator can become very clear. Subsequent heavy flushes, such as might occur when discharging baths or lavatories, will stir up much of the debris which had settled nearest the entrance zone. However, as flow continues round the passaye 14, channelling ceases and piston flow takes over. The liquid then being discharged is a clear liquor created during a long period of quiescence, this liquid persistin as lony as the turbulent regions do not penetrate to the exit end of the passage 14. By suitable design of volumes and flow rates, outflow liquids can be made to consist only of liquors which have had long settling periods. In this way, the different structures of the invention provides opportunity of extremely clear discharges into drainage and soakaway systems. Chemical characteristics of any dissolved material, as distinct from solids, a ' re unlikely to be affected. A separator as described above can be installed in a linked system having a pre-settling chamber to remove the bulk of low density and high density materials, so maximising the effectiveness of the coils of the passage of the separator. The baffle as has been mentioned above can be either coiled from a straiyht or corrugated sheet. The straight sheet is used in cases where minimum turbulence is required, and a corrugated sheet is used to create controlled turbulence, so discouraging by-pass flow and/or assisting in the formation and ascent of low density globules, and/or the descent of high density materials. The baffle may be of rigid or flexible material. The second vessel 10 may be separate from the first vessel 6 but closely positioned thereto. Variations and other modifications can be made without departing from the scope of the invention described above and as claimed hereinafter.

Claims: CLAIMS : 1. A separator comprising an assembly of a first vessel and an upwardly-oriented elongate unit including a helical baffle forming a spiral passage in said unit, the first vessel having a sump and the unit being in fluid communication with the first vessel, an inlet means being provided to convey a mixture to be separated into the assembly, and at least two outlet means being provided through which the separated components of the mixture are removable from the assembly, the mixture passing through the first vessel and the passage of the unit with a disposable component being discharged and a required residual component being held in the first vessel . 2. A separator as claimed in Claim 1, wherein the unit comprises the baffle and is mounted inside the first vessel with the sump of the first vessel formed in the central portion thereof, the inner part of the baffle being cut-away adjacent to a bottom plate of the first vessel. 3. A separator as claimed in Claim 1 , wherein the unit is a second vessel of smaller dimensions than the first vessel with the baffle therein and is provided upwardly-oriented in the first vessel and extending a predetermined distance thereinto with therebelow a lower part of the first vessel serving as a sump to hold the residual component. 4. A separator as claimed in Claim 3, wherein the unit is arranged to receive the mixture at the inlet end of the passage substantially centrally of the unit to flow around the passage with the disposable component being discharged therefrom at or adjacent to the end of the passage via a pipe through the first vessel, while the residual component flows into the sump of the first vessel. 5. A separator as claimed in Claim 3, wherein the unit is arranged to receive a partially separated mixture, the mixture first having passed through the first vessel to perform an initial separation of the components, the disposable component of the mixture thereafter being discharged from the unit via piping through the first vessel. 6. A separator as claimed in Claim 1 , wherein the unit is a second vessel with the baffle mounted therein, the unit being mounted above the first vessel, the inlet means passiny through the the baffle of the unit with the inner part of the baffle being cut-away adjacent to a bottom level of the second vessel. 7. A separator as claimed in Claim 1 , wherein the unit is a second vessel with the baffle mounted therein, the unit being mounted above the first vessel, the inlet means passing through the unit to terminate below a bottom plate in the unit, an aperture being provided in said bottom plate at or adjacent to an inner end of the passage to allow flow from the first vessel into the inner end of the passage to be discharged adjacent to the top of the unit at or adjacent to the outer end of the passage. 8. A separator as claimed in any one of the preceding Claims, wherein the spiral passage has at least two concentric circling coils. 9. A separator as claimed in Claim 8, wherein an outer coil of the bottom end of the baffle is apertured to allow flow between the part of the passage in the outer coil and the part of the passage in the next adjacent coil. 10. A separator as claimed in any one of the preceding Claims, wherein the baffle is formed from coiled straight sheet. 11. A separator as claimed in any one of Claims 1 to 10, wherein the baffle is formed from coiled corrugated sheet. 12. A separator as claimed in Claim 2, wherein the bottom of the first vessel is shaped as a funnel and a valve is provided at its outlet through which deposited sediment can be drained. 13. A separator substantially as hereinbefore described and as shown in Fig. 1 of the the accompanying drawings. 14. A separator substantially as hereinbefore described and as shown in Figs. 2 and 3 of the the accompanying drawings. 15. A separator substantially as hereinbefore described and as shown in Figs. 4 and 5 of the the accompanying drawings. 16. A separator substantially as hereinbefore described and as shown in Figs. 6 and 7 of the the accompanying drawings. 17. A separator substantially as hereinbefore described and as shown in Fig. 8 of the the accompanying drawings.

Inventors: FOSTER WILLIAM WARWICK, FOSTER, WILLIAM, WARWICK
Applicants: FOSTER WILLIAM WARWICK, FOSTER, WILLIAM, WARWICK
Application year: 1992
Main classification: B01D21
IPC codes: B01D17, B01D21