EP0879090A1

EP0879090A1 - Separator for separation of two liquids

Info

Publication number: EP0879090A1
Application number: EP95940482A
Authority: EP
Inventors: Jacob Kalleberg
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-11-03
Filing date: 1995-11-03
Publication date: 1998-11-25
Also published as: AU4190896A; WO1997016255A1

Abstract

A separator for the separation of two intermixed liquids having two different specific weights, for example, water and oil, comprising a rotating separator bowl (2) having coaxial outlet openings (5, 25, 37) of different diameters, where the separator bowl (2) is divided into two chambers by rotation-symmetrical transverse walls (15, 16) allowing flow communication between the chambers and where an inlet pipe is provided for supplying the intermixed liquids into a first chamber, which is characterized in that the coaxial outlet opening (5) having the smallest diameter is situated in the first chamber, that the rotation-symmetrical walls (15, 16) are provided with one or more coaxial opening(s) (17, 28) of greater diameter than the outlet opening (5) from the first chamber, and that in the end of the separator opposite the first chamber and the coaxial outlet opening (5) from the first chamber are provided two coaxial openings (25, 37) of different diameters.

Description

SEPARATOR FOR SEPARATION OF TWO LIQUIDS

The present invention relates to an improved separator for the separation of two intermixed liquids having different specific weights.

There is a large demand today for the separation of a mixture of two liquids having different specific weights. A typical example of such a mixture is a mixture of water and oil.

On board ships, on offshore installations and in certain industrial plants, water that has been contaminated with oil constitutes a major problem. Large quantities of contaminated water cannot be stored, and more stringent environmental requirements with strict limits for the allowable oil content in waste water necessitate high capacity separation of oil and water with a residual oil content at ppm-level.

Separators are also being used in certain industrial processes such as, for example, the extraction of plant oils. In this case, for economical reasons there is a need for separation of a mixture of water and oil in order to obtain the largest possible oil yield. This natural separation of two liquids of different specific weights using the effect of gravity alone requires a very large facility in order to achieve the desired capacity, and the process is generally quite time consuming if at all practically feasible. Nor would this natural process normally produce the desired purity in the separated phases.

A number of separators are known which are based on the principle of subjecting liquid mixtures to centrifugal forces, whereby the difference in the existent specific weight is increased substantially, resulting in the separation ofthe fluids. The separators based on centrifugal force build on the principle that through utilization ofthe centrifugal forces a liquid annulus is built up in which the heavier liquid will lie furthest out toward the exterior wall ofthe separator, while the lighter liquid will collect in a layer on the inner surface ofthe liquid annulus. As fresh, non-separated liquid is gradually added, the lighter liquid is able to flow out over an overflow rim having a given radius from the axis, while the heavier liquid may flow out over an overflow rim having a larger radius.

There are a number of these types of separators on the market. Some of them, such as the separator for milk described in Swedish Patent Publication No. 44053, for example, have internally mounted stacks of discs for conduction of the liquid in parallel streams. In this system it is important to have the discs situated close together in order to provide a large effective surface.

In NO 157 967 another type of separator is described having a system of guiding and diverting conuses (also referred to as "cones" in the following ] which basically produce a serial flow pattern. This separator is partially divided by a rotation-symmetrical transverse wall forming a physical barrier for the liquids, but still allowing the liquids to flow through an axial opening between the two sections ofthe separator. In the first chamber the incoming liquid is accelerated to the rotational velocity ofthe separator and a liquid annulus is established wherein the lighter liquid primarily collects nearest the center of the separator. Both the lighter and heavier liquid then flow through the axial opening between the chambers where the liquids undergo further separation. To ensure the rotation ofthe liquid, radial walls or impeller plates are provided. Guiding and diverting cones in the first chamber of this separator extend outward from the casing of the separator bowl, while in the second chamber they extend outward from the partition wall between the chambers. The drops of heavy liquid are collected here on the outside ofthe conical members and are driven in toward the center ofthe separator.

In NO 139 341 is described a centrifugal separator for the separation of oil/water mixtures and the removal of gas from the mixture. This separator has a chamber for gas separation situated adjacent to and connected with the inlet for the mixture, where the gas outlet is located at one end ofthe separator, while the outlet for heavy and light liquid is at the other end.

In SE 377 894 is described a centrifugal device consisting of an ordinary centrifuge driven by a partial stream ofthe liquid to be separated. The partition wall separates the chamber in which separation takes place from the drive chamber. The liquid used to rotate the separator is extracted through an opening near one end ofthe separator, while separated light and heavy liquid is discharged through openings in the other end ofthe separator. The liquid that drives the centrifuge and which flows out through the first opening has not undergone any separation in this drive chamber.

These separators do not offer the combination of high capacity and purity required to meet environmental and/or economic requirements. Therefore, it is an objective ofthe present invention to provide a separator affording better separation than the known separators, while at the same time avoiding an undesirable reduction of capacity.

This is achieved according to the present invention by means of a separator for the separation of two intermixed liquids having two different specific weights, for example, water and oil, comprising a rotating separator bowl having coaxial outlet openings of different diameters, where the separator bowl is divided into two chambers by rotation- symmetrical transverse walls allowing flow communication between the chambers and where an inlet pipe is provided for supplying the intermixed liquids into a first chamber, which is characterized in that the coaxial outlet opening having the smallest diameter is situated in the first chamber, that the rotation-symmetrical wall is provided with one or more coaxial opening (s) of greater diameter than the outlet opening from the first chamber, and that in the end ofthe separator opposite the first chamber and the coaxial outlet opening from the first chamber are provided two coaxial openings of different diameters.

The liquid mixture to be separated often contains significant or minor amounts of heavier particles. These particles will then build up on the separator walls, causing them to become clogged. The separator must therefore be stopped at various intervals to remove these sediiments. In processes where the liquids contain major amounts of particles, the separator must be stopped frequently, often resulting in an undesirable interruption in operation.

The separation of large volumes of liquids and solid particles can be accomplished, for example, by means of a so-called decanter. There are numerous such decanters on the market capable of separating two intermixed liquids while simultaneously separating particles out from the mixture. These are basically constructed like a simple separator having a substantially cylindrical separator bowl. Solid particles are driven outward toward the walls ofthe separator bowl. On the decanter is mounted a screw member having an axis identical with the rotational axis ofthe separator bowl. The screw member extends outward toward the wall ofthe bowl and has minimal clearance therewith. During rotation ofthe bowl, the screw member has a slightly deviating rotational speed, with the difference being only some few revolutions per minute, and the solid particles are thus swirled toward one end ofthe separator bowl where the particles are discharged through an opening. This permits continuous operation without the need for periodical stopping and flushing. In SE 155 009, SE 346225, DE 3 802 333 and EP 528 067 there are described decanters or separators having a feed-out screw for particulate material.

SE 155 099, SE 346 225 and DE 3 802 333 describe decanters used to separate one liquid phase from solid matter, whether the desired end product is a solids-free liquid or a solid that has been dewatered to maximum extent. This is achieved with the aid of a screw member in the separator bowl, mounted on the interior structure ofthe separator and lying against or adjacent to the wall ofthe separator bowl so as to be rotatable in relation thereto. Solid matter is screwed by the screw member along the wall ofthe separator bowl toward the outlet for solids.

The known decanters, however, do not provide for a sufficient cleansing ofthe light and heavy liquids to satisfy the increasingly stringent requirements for purity.

EP 528 067 shows this type of "3D" separator. Solids are displaced radially outward by helical fins extending in the longitudinal direction ofthe separator and rotating at a speed different from that ofthe separator.

Another objective ofthe present invention is to provide a separator having the above mentioned properties but which permits continuous operation even with liquid mixtures having a high particle content.

This is achieved according to the present invention by a separator ofthe aforementioned type which is characterized in that the radial walls, the flow conducting elements, the conical members, and the annular plates are mounted on a central tube and are freely rotatable in relation to the separator bowl casing around said tube which has a rotational axis coinciding with that of the separator, where there is (are) provided one or more screw member(s) extending helically in the longitudinal direction ofthe separator and attached to the radial walls against the casing ofthe separator bowl.

The invention will now be described with reference to the accompanying drawings where:

Figure 1 is a view of a longitudinal section of a preferred embodiment ofthe separator. Figure 2 is a view from above of a cross section ofthe separator bowl along line A-A in Figure 1.

Figure 3 is a view from above of a cross section ofthe separator bowl along line B-B in Figure 1.

Figure 4 is a view from above of a cross section ofthe separator bowl along line C-C in Figure 1.

Figure 5 is a view of a longitudinal section of an alternative embodiment ofthe separator.

Figure 6 is a view of a longitudinal section of a second alternative embodiment ofthe separator.

Figure 7 is a cross-sectional view of a diffuser ring.

Figure 8 is a view of a longitudinal section of an embodiment of a decanter-separator.

Figure 9 is a view of a longitudinal section of a second embodiment of a combined decanter-separator.

Figure 10 is view of a cross section along line E-E ofthe embodiment ofthe combined decanter-separator in Figure 9.

Figure 11 is a view of a cross section along line F-F ofthe embodiment ofthe combined decanter-separator in Figure 8.

Figure 12 is a view of a cross section along line G-G ofthe embodiment ofthe combined decanter-separator in Figure 9.

Figure 13 is a view of a longitudinal section of an alternative embodiment ofthe separator.

Figure 14 is a view of a longitudinal section of a second alternative embodiment ofthe separator. Figure 15 is a view of an alternative embodiment ofthe combined decanter/separator in accordance with the invention.

Figure 16 is a view of an enlarged section ofthe area surrounding the coaxial opening having the largest diameter, in the embodiment shown in Figure 1.

The separator shown in Figure 1 is designed particularly for the cleansing of oil-bearing water or other liquids having a relatively low particle content. The casing 2 ofthe separator bowl is surrounded by a separator mantle 1. Separator mantle 1 is stationary and is securely affixed to its surroundings in a manner not shown. The separator is preferably mounted in upright position with the base plate 14 situated at the bottom and the rotational axis vertical. Around the center of base plate 14 is mounted a hood 29 enclosing the primary outlet 5, beneath which is provided a funnel 7 with outlet pipe 31, in addition to discharge opening 30.

Central tube 22 passes through base plate 14 at the center, proceeds into the bottom 12 ofthe separator bowl through primary outlet 5, extends through the entire length ofthe separator and emerges through bearing unit 3 at the top ofthe separator. Central tube 22 is sealed by means of sealing wall 36, and the lower section thereof functions as an inlet pipe 8. Inlet openings 9 on central tube 22 are surrounded by a deflection cup 10. The upper portion ofthe central tube is an inlet pipe for supply of washing fluid through the inlet for washing fluid 32. On central tube 22 are mounted a plurality of jet nozzles 21. Jet pod 35 with nozzles 21 passes through partition wall 36 and down through central tube 22.

Radial walls or impeller plates 1 1 extend out from casing 2 of the separator bowl toward the center along the entire internal length ofthe separator bowl. Impeller plates 1 1 are mounted at equidistant intervals, and there are preferably provided four such impeller plates in a separator bowl. The internal length ofthe separator bowl is divided into two sections by two annular plates 15 and 16 which are mounted for symmetrical rotation, and are spaced with a slight displacement therebetween in the longitudinal direction. The annular plates 15 and 16 are mounted on impeller plates 1 1.

A plurality of guiding and bypass conuses 18 are mounted in vertical succession asymmetrically on impeller plates 1 1, above annular plates 15 and 16. There may also be mounted one or more deviation rings 19 on or near casing 2 ofthe separator bowl, and a diffuser ring 33 near the passage 24 for heavy liquid. Uppermost in the separation chamber are two coaxial outlets 25 and 37 leading to outlet passages 20 and 27.

The separator bowl is rotated by means of a driving belt 4 powered by a motor, not shown. The separator bowl is suspended from the top thereof in a bearing unit 3 and depends therefrom within the separator casing.

The separator functions as follows:

The liquid in separator bowl 2 is caused to rotate, and continued rotation is maintained by impeller plates 11. Due to centrifugal force the liquid will form a liquid annulus with its center being the axis ofthe separator.

The liquid to be separated is fed into the separator through inlet 8 by force of natural fall or via a pump and is driven through inlet openings 9, preferably leading out into an inverted deflection cup 10 wherefrom the liquid is distributed into the separator's first chamber, the coalescence chamber, and begins to rotate as it is taken up and carried by the already rotating liquid in the chamber.

The impeller plates 1 1 in the coalescence chamber are sufficiently short so as to remain well below the liquid surface at all times and thereby avoid agitation ofthe liquid. Impeller plates 1 1 in the coalescence chamber preferably have a bent end as shown on Figure 2 for maximum efficiency in catching the water.

As the incoming liquid gathers speed, the light phase will settle in a layer in toward the center of the liquid annulus that has formed. This light phase is prevented from flowing into the other chamber by a water lock formed by plate 15. Plate 15 has a diameter larger than the diameter of outlet 25 for the light phase. This ensures the build-up of fluid to a specific fluid level within the coalescence chamber.

The liquid entering through inlet openings 9 first meets the layer of light liquid. Larger and smaller droplets of light liquid in the incoming mixture will seek to merge with this layer rather than following along with the heavier liquid through the layer. In this manner most ofthe light liquid is collected in a layer closest to the axis of rotation of the liquid annulus formed in the coalescence chamber. When this liquid annulus has built up to the extent that it comes within a radius defined by primary outlet 5, the light phase in the coalescence chamber will flow out through this outlet. Fluid catcher 6 assists in conducting the liquid out when the fluid level comes within a radius defined thereby. The light liquid then runs down toward base plate 14 and may be gathered up by an optional funnel 7 and conducted out through outlet 31 , or it may run out through opening 30. Screen 29 traps the light phase.

When the partially cleansed heavier liquid has attained sufficient speed it is able to flow into the main chamber ofthe separator through annular openings 17 and 28. Here the liquid is held in continuous rotation by the rotation ofthe separator bowl and by the impeller plates 1 1.

In its movement toward outlets 25 and 37, the liquid meets guide conuses 18, which guide the liquid inward toward the smaller diameter at the inside of the cones. Any light liquid present here will be conducted upward and inward toward the smaller radius at the inside of cones 18, while the major part ofthe heavier liquid will migrate toward a larger diameter and thereby out of cone 18 again. Cones 18 will thus cause the liquid in the inner volume ofthe separator to divide into two parallel, axial streams. The heavier liquid will have a low radial velocity, facilitating the separation between the light and heavy phases. To further urge the liquid stream toward the center ofthe separator and thereby advance the separation process, one or more deviation rings 19 may be mounted on or near casing 2 ofthe separator bowl. The function of cones 18 and deviation rings 19 is to conduct any oil in the principally axial stream of liquid in the separator inward toward the center thereof. When the liquid stream is guided by these devices inward toward the separator center, the heavier liquid, due to its greater density, will again preferably seek to migrate out ofthe cone toward the periphery while the lighter liquid will ascend on the surface in toward the center ofthe separator.

Cones 18 may be identical or different and may have a varying pitch angle, as well as different maximum and minimum opening diameters. Cones 18 may also have varying placement in relation to each other. Because it is the inner face of cones 18 that catches the oil, it is important that the cones be positioned sufficiently far apart to allow the oil drops that have passed outside one ofthe cones 18 to rise in order to be caught by the next cone in the direction of flow. The top radius ofthe first cone determines the amount of liquid constituting the internal flow volume, which is the difference between the top radii and the liquid surface. In this volume, or in the layers, emulsions lighter than water are separated. Also, water particles are separated from oil here. It is advantageous that the first cone 18 with which the water comes in contact has the smallest bottom radius, while the bottom radii increase and the top radii decrease for each cone 18 in upward progression within the separator.

To ensure a partial serial flow where the top layer ofthe axial stream is conducted slightly inward toward the center of each cone 18, but where the heavier liquid flows out again toward the periphery while the lighter liquid rises in toward the center, cones 18 must be spaced a specific distance apart. Moreover, the lateral rims of cones 18 may have different pitch angles, ranging all the way from that of an approximately annular wall to that of an approximate cylinder.

The light liquid remaining after the separation in the first stage will collect in a layer closest to the axis of rotation in the second chamber ofthe separator. When the liquid level then comes within a radius defined by coaxial opening 37, the heavy liquid may flow out through passage 24 over plate 39, and out through passage 37 before being conducted in ducts out through opening 20. It is preferable that there be blades 23 mounted on plate 39. These blades take up the kinetic energy ofthe liquid as it is driven inward toward the smaller diameter and facilitate its discharge. Here, a large portion of the energy imparted to the liquid is thereby recovered. When the radius ofthe liquid annulus reaches a diameter defined by opening 25, the light liquid flows over this rim and out through opening 26, and is conducted out through duct 27.

At specific intervals the separator bowl 2 must be cleansed of solid particles that have settled. The separator must then be stopped and emptied of its contents. A washing fluid is then supplied through central tube 22 and fed out through nozzles 21. To supply the washing fluid to the first chamber, a nozzle tube, or jet pod 35 is mounted in the lower section of central tube 22 below partition wall 36. During washing, the separator bowl 2 is slowly rotated while being flushed internally with washing fluid. Washing fluid and loosened sediments then run down along the walls ofthe separator bowl and out through the primary outlet. Opening 28 facilitates the flushing by permitting the washing fluid and loosened sediments to follow along the wall. It may also be advantageous for deviation ring 19 to be provided with an aperture against the casing so as to avoid creating a hindrance during washing. In many cases this aperture or slot may also have a positive effect on the process, as this opening facilitates the upward flow. Any deviation is a hindrance where water is concerned. From time to time in maintaining and washing the separator, it may be necessary to open the separator bowl. Base plate 14 is then screwed off, whereupon the bottom 12 of the separator bowl may be removed by loosening locking ring 13. The entire spherical body, or bowl, may be then be withdrawn.

In the separation of liquids having different densities and which at the same time contain solid particles, considerable quantities of sediment will collect along the outer wall in a separator such as the one described above. This will necessitate frequent interruption of operation and washing. It would be feasible to install a decanter and separator, according to the present invention, in series, although this is an expensive and complicated solution. Figures 8 and 9 show two combined decanter-separators which in principle are self-cleaning separators in accordance with the present invention.

Both ofthe combined decanter-separators shown in Figures 8 and 9 are based on the principle that the separator casing and the interior structures of a separator are freely rotatable in relation to one another.

In the two embodiment shown in Figures 8 and 9, the top plate 39, impeller plates 11, cones 18, deviation ring(s) 19, walls 15 and 16 and bottom 44 constitute an aggregate unit which is rotatably suspended at the top and bottom ofthe separator bowl. The whole unit is affixed at the top thereof to central tube 43. Annular plate 16, impeller plates 1 1 and bottom 44 form a unit in the extension of central tube 43, and the extension of bottom 44 rotates in an opening, or hole, at the bottom 12 ofthe separator. To ensure the free rotation ofthe separator bowl in relation to the internal components, the axis of rotation may be lubricated via lubricating nipple 54 and fog-lubricated with oil mist injected through lubricating tube 52 and opening 53.

The impeller plates are preferably enclosed by a perforated cylinder 40, on the outer surface of which is affixed a screw member 41 consisting of a flat bar extending in helical form down the surface ofthe cylinder. The clearance between screw member 41 and casing 2 of the separator bowl should be minimal, avoiding metallic contact between the components. The casing 2 ofthe separator bowl and the interconnected internal structures are driven by a motor or motors, not shown, via belt pulleys 46 and 46'.

In operation ofthe decanter-separator, solid particles are driven outward toward the casing 2 ofthe separator bowl and collected there. Casing 2 ofthe separator bowl and screw member 41 are driven to rotate with a specific deviation in their rotational speeds, causing particles on the inner surface ofthe separator casing to be propelled helically downward in the separator. The difference in rotational speeds is dependent on, among other factors, the particle content ofthe washing composition. With a low particle content the difference may be as small as from 1 to 5 revolutions per minute, whereas with a high particle content a difference as great as from 25 to 50 revolutions per minute may be necessary.

The embodiments shown in Figures 8 and 9 are, respectively, an embodiment providing for periodical particle discharge and one providing for continuous particle discharge.

Figure 8 shows an embodiment for periodical discharge. Here the particles are gathered in the collection chamber 47. At certain intervals the valves 48 are opened and the particles are hurled out against shield 42 and descend onto base plate 14 where they may be removed by various means. Valves 48 may be opened in different ways. In the embodiment shown on Figure 8, water is flushed at specific intervals through pipe 51 into annular chamber 58, from when the water is conducted through openings 50 into corresponding cups 49 to fill the latter with water. The cup and valve are rotatably mounted about axis 57, and when cup 49 is full, cup 49 pivots out and valve 48 swings in and opens. When the supply of water is interrupted, cups 49 are emptied and valve 48 closes again.

Figure 9 shows an embodiment for continuous discharge. Here, there is securely affixed below bottom 44 a conical member 45, onto which screw member 41 is mounted. Conical member 45 with screw member 41 fit down into a conical cavity in the base section 56, causing the particulate material that is helically propelled down along casing wall 2 ofthe separator bowl to be rotated inward and downward toward the axis ofthe separator axis and discharged through opening 59 on the outside ofthe extension of bottom 44. From here the particulate sludge is hurled out opening 55 toward shield 42 and is drained out through openings 58. Base section 56 is adjustable to accommodate eventual wear and tear by means of regulating screws 61.

Figure 13 shows an embodiment wherein a new separator bowl 2 with contents in accordance with the present invention has been placed in a separator casing 1 , 80 from an older, traditional separator. By this means, the customer is able to save money by retaining the separator casing with its driving gear and inlet and outlet connections, without the need for additional alterations relating to the system in other respects. The separator is driven from the bottom by motor 81 mounted on base 82 via a flexibly suspended drive shaft 67. The liquid to be separated enters through inlet 8 at the top of the separator and runs through central tube 22 and into the separator's first chamber or coalescence chamber toward deflection cup 10. As in the other embodiments, a first separation takes place here, and the light phase is removed through primary outlet openings 5 and is hurled out between partition walls 93, 94, collected therebetween, and conducted out through tube 95. For washing ofthe separator, a flush water pipe, or jet pod, 35 with nozzles 21 is mounted on the central tube As described above, the separator is emptied before flushing, the flush water is injected through jet pod 35 out through nozzles 21, and the water running downward in the separator bowl will exit the separator bowl through openings 5 and be conducted out ofthe separator casing through duct 92.

Figure 14 depicts an alternative embodiment ofthe separator shown in Figures 1 , 5 and 6 with an inlet pipe 8 corresponding to that shown in Figure 8. Additional differences from what is shown in the remaining figures are an extra jet pod 35 with nozzles 21 below the hood 29, a combination of deflection cup 10 and wall 15, and the fact that two ofthe cones 18 are approximately cylindrical.

Otherwise the structure ofthe separator shown in Figures 13 and 14 corresponds to that ofthe separators shown on Figures 1, 5 and 6.

Figure 15 shows a combined separator and decanter which in the same manner as for the separator shown in Figure 13, may be inserted into an existing separator casing and, in its basic features, has a structure similar thereto.

Hole 91 in base plate 63 leads to primary oil outlet 5 through slide valve 66 and slide valve housing 65. Oil outlet 5 has the form of one or more holes leading further to one or more outlets 93 for unseparated oil from the first chamber.

Similarly to the embodiment shown in Figure 8, the apertures 64 for particles or sludge are normally closed. Particles or sludge are propelled downward by screw member 41 and collected in the annular chamber 83. In the embodiment shown in Figure 15, apertures 64 are periodically opened for particles by means of axial displacement of slide valve 66 toward slide valve housing 66, which is fastened to the separator bowl by an eye nut 68. Particles, together with some partially cleansed light liquid, are then hurled out and collected in the lower section 80 ofthe separator casing and may be drained out together with the heavy liquid exiting from primary oil outlet 5 during operation or after the separator has been stopped. Outlet 64 is then closed as slide valve 66 is slid back into place on a signal from the outside.

As in the embodiment shown in Figure 13, the separator is driven by motor 81 on base 82 via drive shaft 67. To provide for the difference in rotational speed between the separator bowl and the internal structures within the separator bowl, as in the other embodiments of separator/decanters above, the pulley 77 coupled to the body ofthe bowl 2 drives the toothed belt 75, which in turn drives the double pulley 72 mounted in bearing 71. Pulley 72 then drives toothed belt 74, which drives pulley 76 attached to central tube 43. The difference in diameter between pulley 76 and pulley 77 thereby provides the necessary difference in speed of 5 to 20 revolutions per minute required to render the screw capable of cleansing the walls ofthe separator bowl of particles and sludge. Preferentially the pulleys and belts are protected by a bonnet 70, 73. In the lower section ofthe separator bowl the central tube 43 with the internal structures for the separator are mounted with the aid of control unit 85 against bearing member 62. Bearing member 62 is also a part of base plate 63 which binds the radial walls together at the bottom.

At its uppermost end the body ofthe separator bowl is mounted against the center tube in ball bearing 86. The separator bowl is elastically suspended within separator mantle 1 by an elastic member 69, e.g., an O-ring or coil springs.

In cases where it is difficult to have outlet 5 built in to the apparatus, the effect of this outlet may be compensated for, to a certain extent, by a higher r.p.m. (revolutions per minute) for the separator or by the supplying of a smaller amount of liquid.

Claims

P a t e n t l a i s

1.

A separator for the separation of two intermixed liquids having two different specific weights, for example, water and oil, comprising a rotating separator bowl (2) having coaxial outlet openings (5, 25, 37) of different diameters, where the separator bowl (2) is divided into two chambers by rotation-symmetrical transverse walls (15, 16) allowing flow communication between the chambers and where an inlet pipe is provided for supplying the intermixed liquids into a first chamber, characterized in that the coaxial outlet opening (5) having the smallest diameter is situated in the first chamber, that the rotation-symmetrical wall (15, 16) is provided with one or more coaxial opening (s) (17, 28) of greater diameter than the outlet opening (5) from the first chamber, and that in the end ofthe separator opposite the first chamber and the coaxial outlet opening (5) from the first chamber are provided two coaxial openings (25, 37) of different diameters.

2.

A separator in accordance with claim 1, characterized in that the rotation- symmetrical wall consists of two rotation-symmetrical plates (15, 16) axially displaced in relation to one another, where the diameter ofthe smallest plate (15) is greater than the diameter at the coaxial opening (25) which is at the smallest diameter in the other chamber.

3.

A separator in accordance with one or more ofthe preceding claims, characterized in that there are provided radial walls (11) extending in the entire longitudinal direction of each ofthe chambers.

4.

A separator in accordance with one or more ofthe preceding claims, characterized in that conical members (18) are mounted with symmetrical rotation about the rotational axis ofthe separator, where the conical members have their largest opening toward the first chamber.

5.

A separator in accordance with one or more ofthe preceding claims, characterized in that on or near the inner wall ofthe separator bowl (2) there is (are) mounted one or more flow conducting elements (19).

6. A separator in accordance with one or more ofthe preceding claims, characterized in that the radial walls (11), the flow conducting elements (19), the conical members (18), and the rotation-symmetrical plates (15, 16) are fastened together into a continuous unit which is mounted free ofthe casing (2) ofthe separator bowl, permitting them to rotate freely in relation thereto about identical axes of rotation, where there is (are) provided one or more screw member(s) (41 ) extending in helical form in the longitudinal direction ofthe separator and surrounding the radial walls (11) closest to the casing (2) ofthe separator bowl.

7. A separator in accordance with claim 6, characterized in that the screw member (41) along the entire or partial length ofthe separator is mounted on the outside of a perforated cylinder (40) affixed to the radial walls (11).

8. A separator in accordance with claim 6 or 7, characterized in that the screw member below the bottom ofthe first chamber is adapted to follow along the surface of a conical member (45) down into a conical cavity in the base section (56).

9. A separator in accordance with claim 6 or 7, characterized in that below the lower end ofthe screw member (41) is provided a collection chamber (47) for solid particles.

10. A separator in accordance with one or more ofthe claims 6 to 9, characterized in that the separator bowl (2) and the screw member (41 ) are driven with a difference in rotational velocity of 1 to 50, preferably 5 to 25, and most preferably about 10 revolutions per minute.