WO2018204821A2

WO2018204821A2 - Apparatus for separating solids, liquids and gases with integral drive motor having a hollow motor shaft defining an impeller drum

Info

Publication number: WO2018204821A2
Application number: PCT/US2018/031146
Authority: WO
Inventors: John A. DI BELLA; Alberto Di Bella
Original assignee: Schlumberger Canada Ltd; Services Petroliers Schlumberger SA; Schlumberger Technology BV; Schlumberger Technology Corp
Current assignee: Schlumberger Canada Ltd; Services Petroliers Schlumberger SA; Schlumberger Technology BV; Schlumberger Technology Corp
Priority date: 2017-05-05
Filing date: 2018-05-04
Publication date: 2018-11-08
Anticipated expiration: 2019-11-05
Also published as: WO2018204821A3; CA3062542A1

Abstract

An apparatus for separating a fluid having a lighter specific gravity from a fluid having a heavier specific gravity and for separating fluids having lighter specific gravity from fluids having a heavier specific gravity includes an electric motor including an annular stator and a rotor having a rotor shaft having a hollow interior defining a rotatable drum having a drum rotational axis, the rotor passing through the stator and rotatably mounted on shaft mounting structure; a fluid passage structure for receiving fluids and solids of a mixture stream to be separated having a longitudinal axis, the fluid passage structure including a the rotatable drum and an impeller contained within the rotatable drum for separating with centrifugal force the constituents of the stream into radially arrayed layers of progressively increasing specific gravity.

Description

APPARATUS FOR SEPARATING SOLIDS, LIQUIDS AND GASES WITH INTEGRAL DRIVE MOTOR HAVING A HOLLOW MOTOR SHAFT DEFINING AN

IMPELLER DRUM

BACKGROUND

The present invention relates generally to the field of devices for separating flowable material from immiscible gaseous, fluid and solid mixtures. More specifically the present invention relates to an axial flow pump apparatus for separating immiscible fluids, and preferably solids as well, having different specific gravities, including separating particulate solids from liquids, and solids from other particulate solids, liquids from liquids, and gases from liquids.

Description of the Prior Art:

There have long been separating devices for separating materials in mixtures having different specific gravities. Yet none have satisfactorily and economically separated particulate

solids, liquids and/or gases from liquids without a pressure drop and with a small footprint, despite the need for such devices.

Separation of contaminants including solids, liquids and gases from a composite fluid stream is needed in virtually every industry such as petroleum, sewage, manufacturing and mining, to name a few. In the oil and gas industry, produced water comprises over 98% of the total volume of exploration and production wastewater produced in the United States. Produced water is the associated water that is produced along with oil and/or gas during normal production operations. Produced water is not a marketable product, so it must be disposed of (with this said, many companies are now seeking ways to purify the water to drinking water standards). Produced water may be contaminated with either oil, solids, gases or a combination thereof. In many land-based production operations, the produced water is either injected into a disposal well or is reinjected into a producing well to maintain reservoir pressure and enhance oil recovery. Produced water must be treated prior to re-injection because many of the components can be harmful to the formation or the associated piping. In the case of suspended oil associated with the produced water, it can be separated and sold to generate revenue for the facility.

Millions of gallons of diesel fuel and jet fuel are transported by ships to various parts of the world for refueling of planes at sea and for delivery to ports. These transport ships contain many compartments for holding the diesel and jet fuel. While the fuels are in these compartments, they may become contaminated with water. However, fuel contaminated with water is unsuitable for use. Thus, at the point of delivery, any fuel contaminated with water will be rejected, and must be returned to the point from which it was shipped for refinement. The re- transportation and refinement of the fuel is both costly and time consuming.

Centrifugal separators for the separation of immiscible fluids of different specific gravities are well known. These centrifugal separators employ a rotor for rotating the mixture of fluids, causing the fluid having the lighter specific gravity to migrate to the center of the rotating mass, and the fluid having the heavier specific gravity to migrate to the perimeter, where it be extracted. Examples of such centrifugal separators are disclosed in U.S. Pat. No. 4,478,712 to Arnaudeau, U.S. Pat. No. 3,517,821 to Monson et al., German patent No. 1 , 186,412 to Groppel, and Swiss patent No. 563, 186 to Reynolds. Flow pumps and blowers built on the same general principle are disclosed in U.S. Pat. No. 1 ,071 ,042 to Fuller and U.S. Pat. No. 3,083,893 to Dean, respectively, and in U.S. Pat. Nos. 3,276,382, 3,786,996, and 3,810,635.

However, none of these devices provides a sufficiently great G-force in a continuous flow and without a significant pressure drop to create a well-defined boundary between the fluids as they separate under centrifugal force, e.g. by forcing the fluid having the lighter specific gravity to a tight core in the center of a tube of the fluid having the heavier specific gravity, whereby the fluid having the heavier specific gravity can be drawn off in a single pass without the need for additional treatment of the fluid having the lighter specific gravity. Further, none of these devices provides an adjustable mechanism for drawing off the fluid having the heavier specific gravity.

SUMMARY

An apparatus is provided for separating a fluid having a lighter specific gravity from a fluid having a heavier specific gravity and for separating fluids having lighter specific gravity from fluids having a heavier specific gravity, the apparatus including an electric motor including an annular stator and a rotor having a rotor shaft having a hollow interior defining a rotatable drum having a drum rotational axis, the rotor passing through the stator and rotatably mounted on shaft mounting structure; a fluid passage structure for receiving fluids and solids of a mixture stream to be separated having a longitudinal axis, the fluid passage structure including a the rotatable drum and an impeller contained within the rotatable drum for separating with centrifugal force the constituents of the stream into radially arrayed layers of progressively increasing specific gravity, with solids at the outer layer; and a discharge manifold in fluid communication with the rotatable drum for individually separating stratified layers of the mixture; so that the impeller axially propels the steam through manifolds for selective layer removal through radially placed removal pipes.

The impeller may include a number of impeller blades mounted within the drum and protruding radially inward toward the drum rotational axis. The rotational drum may include a drum inlet coupled to a mixture input conduit for delivering the mixture from a mixture source to the rotatable drum, and a drum outlet sealingly and rotatably coupled to a mixture output conduit leading to the manifold, so that the drum is rotatable about the rotatable drum axis relative to the mixture input conduit and to the mixture output conduit. The apparatus may additionally include a solid removal pipe along the discharge manifold for separating a solid from the fluid mixture which has been stratified by rotation of the mixture and discharging the solid.

An apparatus is further provided for separating a fluid having a lighter specific gravity from a fluid having a heavier specific gravity and for separating fluids having lighter specific gravity from fluids having a heavier specific gravity, the apparatus including an electric motor with an annular stator and a rotor having a rotor shaft having a hollow interior defining a rotatable drum having a drum rotational axis and a drum inlet and a drum outlet, the rotor passing through the stator and rotatably mounted on a shaft mounting structure; a fluid passage structure for receiving fluids and solids of a mixture stream to be separated, the fluid passage structure having a longitudinal axis and including a the rotatable drum and a rotatable impeller positioned in the fluid passage structure for imparting a swirling axial movement to the fluids in the fluid passage structure downstream of the impeller means and in the discharge conduit and causing the fluids and solids having the heavier specific gravity to migrate outwardly to form a radial array of circumferential layers of progressively heavier specific gravities from the center of the mixture stream outwardly; a discharge manifold in fluid communication with the rotatable drum for separating individual stratified layers from the mixture; and discharge means connected to the discharge conduit for selectively discharging the fluids of each given layer of the mixture stream.

The impeller may include at least two concentric helical blades each having an inlet end and an outlet end, and the helical blades each terminating short of the longitudinal axis of the fluid passage means to define a hollow core through which the fluids pass.

The apparatus may additionally include a solids separation structure including an inlet gap defined between the drum inlet and the motor and an inlet solids receiving chamber defined between the rotor and the motor and having an inlet solids discharge port for draining solids collected in the inlet solids receiving chamber, and an outlet gap defined between the outlet gap and the motor and an outlet solids receiving chamber defined between the rotor and the motor and having an outlet solids discharge port for draining solids collected in the outlet solids receiving chamber.

The apparatus may additionally include an inlet discharge pipe in fluid communication with the inlet solids discharge port. The apparatus may additionally include an outlet discharge pipe in fluid communication with the outlet solids discharge port. The hollow rotor shaft preferably is tubular. The shaft mounting structure may include a shaft bearing structure.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the following drawings, in which:

FIG. 1 is cross-sectional side view of a fluid axial flow type pump operated by a hollow rotor shaft of a drive motor in accordance with the present invention.

FIG. 1 A is a front perspective view as in FIG. 1 showing the apparatus motor, rotor and drum, the inventive inlet and outlet solids separation mechanisms, including the inlet and outlet gaps, inlet and outlet solids receiving chambers located between the rotor and the motor, inlet and outlet solids discharge ports opening from receiving chambers into a radial and downwardly protruding inlet and outlet discharge pipes. FIG. 2 is a cross-sectional side view of a fluid axial flow type pump with seals in accordance with the present invention;

FIG. 3 is an elevational view of the pump of FIG. 2;

FIG. 4 is a right side elevational view of the pump of FIG. 2;

FIG. 5 is a top plan view of the pump of FIG. 2; and

FIG. 6 is a partial cross-sectional side view of the pump and discharge manifold of

FIG. 2.

DETAILED DESCRIPTION

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.

It is thus a feature of the present disclosure to provide a method and apparatus for separating immiscible fluids having different specific gravities which greatly simplifies the mechanical complexity of the device by eliminating the need for couplings, belt drives, and sprockets, and for bearings outside the drive motor.

It is another feature of this disclosure to provide a method and apparatus for separating immiscible fluids having different specific gravities with a compact device with reduced size and cost.

It is still another feature of this disclosure to provide a method and apparatus capable of separating liquids, solids and/or gases from liquids and from each other in immiscible fluids having different specific gravities with only one treatment stage.

It is finally a feature of the present disclosure to provide such a method and apparatus in which mechanical wear of bearings is not an issue for reliable operation, and the life of the apparatus is increased greatly, and as much as ten fold or more.

The mixture stream of solids, liquids and gases is rotated as it passes through the rotating drum, which takes the form of a hollow, and preferably tubular rotor shaft of an electric motor, the rotor shaft having inwardly protruding impeller blades. The rotor shaft and surrounding rotor pass through the stator of the motor to separate with centrifugal force the constituents of the stream into radially arrayed layers of progressively increasing specific gravity, with solids at the outer layer. The inwardly protruding impeller blades axially propel the steam through manifolds for selective layer removal through radially placed removal pipes. Where solids are removed, they are discharged through a removal pipe along the discharge manifold. At least one and preferably both ends of the drum preferably are sealingly and rotatably coupled to conduits, specifically to a mixture input conduit at the drum inlet end delivering the mixture from the mixture source to the drum, and a mixture output conduit leading to the manifolds so that the drum is rotatable about its axis relative to the conduits.

The optional solids separation means preferably are provided at the drum inlet and drum outlet to enhance the efficiency of solids separation and the rotational efficiency of the drum so that friction resistance to rotation is eliminated and much greater rotational speeds can be reached with high separation efficiency.

The inlet and outlet solids separation mechanisms at the rotatable drum inlet and drum outlet, greatly increase solids removal efficiency and apparatus operation. Inlet solids separation mechanism includes an annular inlet gap between the motor and drum inlet of at least 1/20,000 inch, opening into an annular inlet solids receiving chamber located between the rotor and the motor. An inlet solids discharge port opens from inlet solids receiving chamber into a radial and downwardly protruding inlet discharge pipe. By the same token, the outlet solids separation mechanism includes an annular outlet gap between the motor and the drum outlet of at least 1/20,000 inch, opening into an annular outlet solids receiving chamber between the rotor and the motor. An outlet solids discharge port opens into a radial and downwardly protruding outlet discharge pipe.

As a result, when the motor is operating, the drum and impeller rotate to produce a vortex in a mixture stream, referred to by the present applicant's trademark name VORAXIALTM, in the stream in the rotor shaft so that centrifugal forces are produced to separate solids, liquids and gases having different specific gravities.

This vast improvement discovered by applicant using an electric motor with a hollow rotor shaft has been entirely unrecognized in the materials separation industry. Applicant has found that using the hollow rotor shaft of a motor to spin the cylindrical rotor assembly and pump the fluid increases the separator reliability, reduces system size and complexity, and reduces the system cost. This is a high reliability rotating separator with no bearings other than any the drive motor may contain , and no mechanical transmission devices. That is, there is no need for separator bearings outside the drive motor, which are typically the first components to fail, and no need for couplings, belts or sprockets. Examples of mixture combinations of material phase components which can be separated from a mixture by the present hollow rotor shaft separator apparatus include:

Liquid / liquid

Liquid / solid

Liquid / liquid / solid

Liquid / solid / solid

Liquid / liquid / gas

Liquid / solid / gas

Liquid / liquid / solid / gas

Liquid / solid / solid / gas

Liquid / gas

where solid / solid combinations are particulate solids moving within a flow stream.

Reference is now made to the drawings, wherein like characteristics and features of the present invention shown in the various FIGURES are designated by the same reference numerals.

An apparatus 10 is disclosed for separating immiscible fluids and solids having different specific gravities from a liquid and solids mixture in FIG. 6.

Separator 10 comprises a fluid flow device 100 (FIG. 2) of the axial pump type in the form of an electronic motor 120 having a hollow rotor shaft 1 12 a drive motor 120 having seals, a discharge manifold 200, and an upstream discharge conduit 300 connecting fluid flow device 100 and discharge manifold 200, as disclosed in U.S. Patent Number 5,084, 189 issued to the present applicant on January 28, 1992, the contents of which are incorporated by reference. Here, the electric motor 120 with hollow drive shaft 1 12 is the fluid flow device. See FIGS. 1 and 2. Discharge manifold 200 can be fluid connected to a downstream discharge conduit 400 for carrying the fluid having the lighter specific gravity. As illustrated in FIG. [[2]] 1 , axial pump 100 comprises fluid passage means including the hollow rotor shaft 1 12, which defines a rotatable conduit or cylindrical rotatable drum 1 10 mounted for rotation and having two ends in the form of a drum inlet 122 and a drum outlet 124. Drum 1 10 provides a passageway for the fluids and solids.

A feature of the present disclosure is that the rotating drum 1 10 is an integral part of the electric drive motor 120. The mixture stream of solids, liquids and gases is rotated as it passes through the rotating drum 1 10, which takes the form of a hollow, and preferably tubular rotor shaft of an electric motor, the rotor shaft having inwardly protruding impeller blades 140. The rotor shaft 1 12 and surrounding rotor 1 14 pass through the stator 1 16 of the motor 120 to rotate drum 1 10 and separate with centrifugal force the constituents of the stream into radially arrayed layers of progressively increasing specific gravity, with solids at the outer layer. The inwardly protruding impeller blades 140 axially propel the steam stream through a discharge manifold 200 for selective layer removal through radially placed removal pipes (not shown). Where solids are removed, they are discharged through a solids removal pipe (not shown) along the discharge manifold 200. Additional solids discharge is provided at the solids discharge pipe in manifold 200. At least one and preferably both ends of the drum 1 10 are sealingly and rotatably coupled to discharge conduit 300 (FIG. 2) so that the drum 1 10 is rotatable about its axis relative to conduit 300.

The optional solids separation means preferably are provided at the drum inlet 122 and drum outlet 124 to enhance the efficiency of solids separation and the rotational efficiency of the drum 1 10 so that friction resistance to rotation is eliminated and much greater rotational speeds can be reached with high separation efficiency.

The inlet and outlet solids separation mechanisms at the rotatable drum inlet 122 and drum outlet 124, greatly increase solids removal efficiency and apparatus operation. The impeller preferably comprises helical blades 140 formed integrally with drum 1 10 to rotate with drum 1 10.

The apparatus of the present disclosure includes inlet and outlet solids separation mechanisms (not shown) at the rotatable drum inlet 122 and drum outlet 124, to greatly increases solids removal efficiency and apparatus operation. Inlet solids separation mechanism includes an annular inlet gap (not shown) between the motor 120 and drum inlet 122 of at least 1/20,000 inch, opening into an annular inlet solids receiving chamber

(now shown) located between the rotor 130 and the motor 120. An inlet solids discharge port (not shown) opens from inlet solids receiving chamber into a radial and downwardly protruding inlet discharge pipe (not shown). By the same token, the outlet solids separation mechanism includes an annular outlet gap (not shown) between the motor 120 and drum outlet 122 of at least 1/20,000 inch, opening into an annular outlet solids receiving chamber (not shown) between the rotor 130 and the motor 120. An outlet solids discharge port (not shown) opens into a radial and downwardly protruding outlet discharge pipe (not shown).

As the drum 1 10 rotates, the blades 140 rotate the mixture stream fluids and solids within the drum 1 10 so that the solids, which have the highest specific gravity are propelled against the drum 1 10 wall and the fluids stratify into radial layers of progressively increasing specific gravity from the center of the stream outwardly. As the blades 140 propel the flowing mixture stream through the drum 1 10, some of the solids layer enters the inlet and outlet solids receiving chambers through the inlet and outlet gaps, respectively, and is discharged through respective inlet and outlet discharge pipes.

Referring to FIG. 2, blades 140 extend radially inwardly short of the longitudinal axis of drum 1 10 to provide or define an axial hollow core or opening 150. As blades 140 rotate, core 150 will initiate a low pressure area in the center of the flow line, with the high velocity, higher specific gravity fluid on the outer perimeter, as shown with respect to water W in FIG. 6 to provide an inherent separation of the fluids, whether liquids or gases, and of solids. Where the lower specific gravity fluid, solid or gas, L in FIG. 6, gets channeled to the center of the fluid stream while the higher specific gravity fluid, solid or gases, F in FIG. 6 gets channeled to the outside of the fluid stream again providing an inherent separation of the fluids.

Blades 140 preferably have a higher axial pitch at their inlet ends 152 (FIG. 2) which is gradually reduced to a smaller axial pitch at their outlet ends 154. Preferably, blades 140 have an axial pitch of approximately ten inches at their inlet ends 152 and an axial pitch of approximately five inches at their outlet ends 154. Although these axial pitches will provide the desired volume and swirl velocity, they can be varied without departing from the spirit of the invention. These units are scalable in design and thus can be manufactured to various sizes to handle different flow rates.

Blades 140 preferably will supply a flow volume of ten inch axial pitch, and as the helical pitch reduces to five inches, the swirl velocity increases greatly to provide a tight swirling axial movement of the fluids. With the reduction in pitch of blades 140, the swirl velocity and the centrifugal force are both doubled in comparison to blades of uniform pitch.

Because of their configuration, each of blades 140 is in contact with the fluids for a complete revolution. Continuous contact with the fluids for one complete revolution is necessary to change the swirl velocity and provide a smooth transition from low to high centrifugal action. Blades 140 also create less turbulence than, for example, shorter impeller blades would. This is a great advantage when one of the fluids is oil or another liquid which is easily emulsified, as the reduced turbulence will prevent emulsification.

Axial pumps such as pump 100 are normally powered and require a suitable power source such as a motor for rotating an input shaft 160 drivingly connected to gearing 170 or a drive belt 172. With the hollow rotor shaft motor shaft design, gearing is eliminated, and the motor and rotating drum is an integral unit. This greatly simplifies the separator design and improves reliability. A detailed description of the structure associated with the drive mechanism for pump 100 can be found in U.S. Pat. Nos. 3,786,996 and 3,810,635, which are specifically incorporated herein by reference, and made a part hereof as though reproduced herein, with respect to their descriptions of the structure associated with the drive mechanism for a pump.

Upstream discharge conduit 300 has an inlet end 310 (FIG. 6) and an outlet end 312. Inlet end 310 can be fluid connected by conventional means to the tank or other container holding the fluids to be separated, at the point of delivery of the fluids. Drum 1 10 (FIG. 2) is conventionally fluid connected at its outlet end 154 to the inlet end 310 of upstream discharge conduit 300. Outlet end 312 tapers outwardly, that is, its outer edge 314 tapers outwardly in the downstream direction from the inner surface 320 to the outer surface 322 of upstream discharge conduit 300, for a purpose to be described hereinafter. The angle of the taper, that is, the angle between edge 314 and outer surface 322 preferably is approximately 12 degrees, to obtain optimum results.

Discharge manifold 200 comprises an axially movable conduit section 210 having substantially the same inner diameter as drum 1 10, and having an inlet end 212 (FIG. 6) and an outlet end 214 (FIG. 2). An upstream seal 220 is affixed to conduit section 210 for sealingly connecting conduit section 210 at its inlet end 212 to the outlet end 312 of upstream discharge conduit 300, and permitting relative axial movement of conduit section 210 and upstream discharge conduit 300. Inlet end 212 tapers outwardly, i.e., its outer edge 230 tapers outwardly in a downstream direction from the inner surface 232 to the outer surface 234 of conduit section 210 for mating engagement with tapered outer edge 314 of upstream discharge conduit 300. For this purpose, the angle formed between outer edge 230 and inner surface 232 of conduit section 210 is substantially the same as the angle formed between outer edge 314 and outer surface 322 of upstream discharge conduit 300.

An adjustment assembly 240 is provided for moving conduit section 210 into and out of engagement with outlet end 312 of upstream discharge conduit 300 for respectively closing and opening discharge manifold 200.

Adjustment assembly 240 comprises a platform 250 extending to discharge manifold 200 upstream of outlet end 312 of upstream seal 220. Upstream seal 220 includes seal members 280, disposed in grooves 282 near upstream end 274 of upstream seal 220, to seal against the outer surface 322 of upstream discharge conduit 300. An operating handle 252 is provided for operating discharge manifold 200. Handle 252 has a distal end 254 extending outwardly from platform 250 and a proximal end 256 by which it is pivotally mounted to platform 250. A link 260 is pivotally mounted at one end to moveable conduit section 210 and pivotally mounted at the other end to proximal end 256 of handle 250 through a slot (not shown) in platform 250. As handle 252 is pivoted, its motion is transmitted to movable conduit section 210 through link 260. Thus, when handle

252 is pivoted towards upstream discharge conduit 300, movable conduit section 210 moves away from upstream discharge conduit 300 to open discharge manifold 200; and when handle 252 is rotated away from upstream discharge conduit 300, movable conduit section 210 moves away from upstream discharge conduit 300 to close discharge manifold 200, and upstream discharge conduit 300. Movable conduit section 210 can be fully engaged, fully disengaged, or any position in between, depending upon the amount handle 252 is rotated. A gauge (not shown) can be provided on platform 250 (e.g. at the slot) to indicate by the position of handle 252 what percentage discharge manifold 200 is open.

Platform 250 has an upstream end 262 and a downstream end 264. A first block 270 joins upstream end 262 to upstream discharge conduit 300 and also acts as a stop for discharge manifold 200 in it full closed position. A second block 272 extends downwardly from downstream end 264 of platform 250 and acts as a stop for discharge manifold 200 in the full open position.

Upstream seal 220 has an upstream end 274 and a downstream end 276. Upstream end 274 seals outlet end 312 of upstream discharge conduit 300. Downstream end 276 is fixed to inlet end 212 of moveable 10 conduit section 210 upstream of link 260, e.g., by a weld 278.

Seals are provided between upstream end 274 relative to outlet end 312 of upstream discharge conduit 300. A circumferential discharge channel 290 is provided at downstream end 276 immediately adjacent the termination of the taper in edge 314 of upstream discharge conduit 300 to receive the fluid of lighter specific gravity circulating adjacent inner surface 320 of upstream discharge conduit 300 when discharge manifold 200 is open. A discharge port 292 opens into discharge channel 290 for receiving and discharging water from discharge channel 290.

Movable conduit section 210 is sealingly connected at its outlet end 214 to downstream discharge conduit 400 with a seal 500 as shown in FIG. 2. Referring now to FIGS. 2 and 6, the operation of the invention will RGW be described with reference of the delivery of diesel or jet fuel from a transport ship, which fuel has been contaminated by sea water. However, it should be understood that application of the invention is not limited to the separation of water and fuel or to use in the context of fuel transport ships, but can be used for the separation of any two fluids having different specific gravities, e.g. oil and water where water is the primary fluid, sludge and treated water in a water purification system, or in reverse osmosis.

In operation, the fluids in their unseparated state are fed into inlet 122 of drum 1 10, which is the hollow rotor shaft 122 of the drive motor 120, using conventional means. As blades 140 rotate, the water W (which has a heavier specific gravity than the fuel L) swirls in a vortex adjacent the inner surface 320 of upstream discharge conduit 300. The fuel F as the primary fluid, occupies the entire flow line. It is noted that, if the water W were the primary fluid, the water W, which then becomes F in FIG. 6, would still migrate to the perimeter, but the low pressure initiated by hollow core 150 would cause the fuel, in this instance L (which has a lighter specific gravity) to be compressed into a tight core around the axis of upstream discharge conduit 300, as shown in dotted lines in FIG. 6. However, if the water W were the primary fluid, then discharge manifold 200 would be replaced by a different discharge manifold, which does not constitute a part of this invention.

With discharge manifold 200 in the full open position as shown in FIG. 6, the water

W will flow between edge 314 of upstream discharge conduit 300 and edge 216 of movable conduit section 210 into discharge channel 290, and out through discharge port

292. The fuel F, separated from the water W, will continue to flow through discharge manifold 200 and out through downstream discharge conduit 400 to its destination. Thus, it will be seen that the present invention provides a unique method for separating immiscible fluids having different specific gravities. While a preferred embodiment of the invention has been disclosed, it should be understood that the spirit and scope of the invention are to be limited solely by the appended claims, since numerous modifications of the disclosed embodiment will undoubtedly occur to those of skill in the art.

While the invention has been described, disclosed, illustrated and shown in various terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.

Claims

Claims:

1 . An apparatus for separating a fluid having a lighter specific gravity from a fluid having a heavier specific gravity, comprising:

an electric motor comprising an annular stator and a rotor shaft passing through the stator, the rotor shaft having a hollow interior defining a rotatable drum with a drum rotational axis;

a fluid passage within the hollow interior for receiving fluids and solids of a mixture stream to be separated the fluid passage having a longitudinal axis;

an impeller within the fluid passage; and

a discharge manifold in fluid communication with the rotatable drum, such that the impeller axially propels the mixture stream through the discharge manifold for selective layer removal.

2. The apparatus of claim 1 , wherein the impeller comprises a plurality of impeller blades mounted within the rotatable drum and protruding radially inward toward the drum rotational axis.

3. The apparatus of claim 1 , wherein the rotatable drum comprises a drum inlet coupled to a mixture input conduit, and a drum outlet sealingly and rotatably coupled to a mixture output conduit leading to the discharge manifold, such that the drum is rotatable about the drum rotational axis.

4. The apparatus of claim 1 , additionally comprising a discharge conduit connected to the drum outlet and comprising an axially movable section.

5. An apparatus for separating a fluid having a lighter specific gravity from a fluid having a heavier specific gravity, comprising:

an electric motor comprising an annular stator and a rotor passing through the stator, the rotor having a hollow interior defining a rotatable drum with a drum rotational axis, a drum inlet and a drum outlet;

a discharge conduit connected to the drum outlet;

a fluid passage within the hollow interior, the fluid passage having a longitudinal axis;

an impeller within the fluid passage; and

a discharge manifold in fluid communication with the rotatable drum and coupled to the discharge conduit.

6. The apparatus of claim 5, wherein the impeller comprises at least two concentric helical blades each having an inlet end and an outlet end, each helical blade terminating short of the longitudinal axis to define a hollow core passage.

7. The apparatus of claim 1 , wherein the hollow rotor shaft is tubular.

8. The apparatus of claim 5, wherein the hollow rotor shaft is mounted on a bearing inside the stator.

9. The apparatus of claim 5, wherein the discharge manifold comprises an axially movable section having a tapered inlet end.

10. The apparatus of claim 9, wherein the discharge conduit has a tapered outer edge for mating engagement with the tapered inlet end of the axially movable section.

1 1 . The apparatus of claim 10, further comprising an adjustment assembly coupled to the axially movable section.

12. An apparatus for separating a fluid having a lighter specific gravity from a fluid having a heavier specific gravity, comprising:

a discharge conduit connected to the drum outlet;

a fluid passage having a longitudinal axis and a rotatable impeller positioned in the fluid passage;

a discharge manifold in fluid communication with the rotatable drum and coupled to the discharge conduit; and

a housing around the rotatable drum.

13. The apparatus of claim 12, wherein the discharge conduit has a tapered outer edge for mating engagement with the tapered inlet end of the axially movable section, and further comprising an adjustment assembly coupled to the axially movable section.