WO2014137219A1 - Drag reducer - Google Patents
Drag reducer Download PDFInfo
- Publication number
- WO2014137219A1 WO2014137219A1 PCT/NO2014/000025 NO2014000025W WO2014137219A1 WO 2014137219 A1 WO2014137219 A1 WO 2014137219A1 NO 2014000025 W NO2014000025 W NO 2014000025W WO 2014137219 A1 WO2014137219 A1 WO 2014137219A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- shield
- rotor
- rotating
- sleeve
- unit according
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
- F01C21/00—Component parts, details or accessories not provided for in groups F01C1/00 - F01C20/00
- F01C21/10—Outer members for co-operation with rotary pistons; Casings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D13/00—Pumping installations or systems
- F04D13/02—Units comprising pumps and their driving means
- F04D13/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D13/08—Units comprising pumps and their driving means the pump being electrically driven for submerged use
- F04D13/086—Units comprising pumps and their driving means the pump being electrically driven for submerged use the pump and drive motor are both submerged
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D25/0606—Units comprising pumps and their driving means the pump being electrically driven the electric motor being specially adapted for integration in the pump
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
- F04D25/0686—Units comprising pumps and their driving means the pump being electrically driven specially adapted for submerged use
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/58—Cooling; Heating; Diminishing heat transfer
- F04D29/5806—Cooling the drive system
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/12—Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas
- H02K5/128—Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas using air-gap sleeves or air-gap discs
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C13/00—Adaptations of machines or pumps for special use, e.g. for extremely high pressures
- F04C13/008—Pumps for submersible use, i.e. down-hole pumping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2230/00—Manufacture
- F04C2230/90—Improving properties of machine parts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2240/00—Components
- F04C2240/50—Bearings
- F04C2240/54—Hydrostatic or hydrodynamic bearing assemblies specially adapted for rotary positive displacement pumps or compressors
Definitions
- the present invention relates to liquid filled machinery, with parts rotating with so high velocity that hydrodynamic friction reduces the efficiency of the machine to a significant degree.
- the machine can be for example electric motors, pumps, compressors, torque converters, mechanical couplings, brakes, flywheels, mechanical couplings, magnetic couplings and magnetic gears.
- Couplings is here meant to include clutches, torque limiters, flexible joints, as well as rigid couplings. More specifically, the invention relates to reduction of hydrodynamic friction in equipment of the mentioned type, particularly embodiments thereof for use subsea.
- Electric motors for use in hybrid-electric and fully electric vehicles use are often partially oil filled (e.g. as in Toyota's Prius and GM's Volt/Ampera) and they operate over a wide speed range.
- the invention might also be applicable to these.
- Electric motors in cooling compressors are also applicable, so are also hydraulic power-packs, in particular when an electric motor and pump/compressor are placed together inside a fluid/liquid filled sealed compartment.
- liquid filled the liquid is typically oil or a mixture of glycol and water.
- the liquid filling reduces the risk for short circuiting (in case of being filled with oil), provides or contributes to cooling and lubrication and facilitates pressure compensation.
- Liquid filled motors for pumps of size, effect and pressure head feasible for pressure boosting of petroleum liquid and multiphase from petroleum wells and other sources are in practice limited to a rotational speed of about 4000 rpm. At higher speed, the frictional losses and heat become a severe and limiting problem. Accordingly, higher rotational speed, which is beneficial for
- the cooling system must be comprehensive and of high capacity, and a comprehensive coolant supply can be required. At locations subsea, often tens or even hundreds of kilometers away from topside installations or shore, this represents severe challenges and high cost.
- the objective of the invention is to provide a solution to the above mentioned limitation, in order to mitigate the problems and challenges and extend the practical speed limit for liquid filled motors, couplings and other units.
- the invention provides a liquid filled, fast rotating unit, such as a motor, a mechanical or a magnetic coupling, distinctive in that the liquid filled unit comprises at least one rotating shield arranged between surfaces of different rotational speed. During operation of the unit, the shield rotates at an
- the shield may be free rotating (i.e. driven by the hydrodynamic drag), or there may be a kinematic link enforcing the intermediate speed.
- rotational speed covers stationary parts to parts of maximum rotational speed, such as the gap between a stationary stator and a rotor, and the gap between a rotor and a stationary housing.
- a freely rotating shield will typically rotate at a speed in between the rotational speeds of the adjacent surfaces of the adjacent objects, for a shield arranged between a stator and a rotor the shield is expected to rotate at about half the rotational speed of the rotor.
- the hydrodynamic losses depend on the speed of the liquid by a power factor of approximately 3.
- the shield provides two volumes of half difference in relative speed, resulting in about 1/8 of the original loss in each of the two volumes .assuming that the gaps between the sleeve and the stator/rotor are equal to what is was before the sleeve was introduced. The sum of losses for both volumes (both sides of sleeve) will in such a case be reduced to
- the technical effect is that the dimensions of the full length or extent of the cooling system and supply chain can be reduced accordingly or the maximum rotational speed and pressure head can be increased, or energy for operation is reduced due to reduced hydrodynamic loss.
- the shield allows a higher maximum rotational speed for a specific demand for cooling, making liquid filled motors and couplings and gears more feasible for multiphase pump and compressor motors.
- the shield is a tube section or sleeve arranged between the rotor and stator, rotor and housing, rotor and shaft, rotor and barrier wall or between any other rotational parts of cylindrical shape.
- the radial gap between said parts forms an annular volume into which the sleeve is arranged so as to rotate freely in the gap.
- the shield is a disc or plate arranged between the rotor and stator, or rotor and housing, or in any other axial gap between rotating parts forming a disc shaped volume.
- This embodiment is relevant for axial couplings, axial motors and generators having rotors with high aspect ratio of diameter vs length.
- the unit is an electric motor driving a subsea pump or compressor and the shield is a sleeve arranged between the stator and rotor and preferably also a sleeve arranged between the rotor and housing if the rotor is external to the stator.
- the sleeve is arranged in the annular gap between any rotational parts of tubular shape, the unit can be a motor of different type than an electric motor, such as a hydraulic motor, or other units.
- the shield is made of a non-ferromagnetic metal, polymer, composite material or ceramic material, if the shield is for arrangements in gaps with a rotating magnetic field. If there is no magnetic coupling between the rotating surfaces, the shield can be made of a ferromagnetic material (and with less resistivity) since there is no magnetic coupling for which magnetic losses can occur. When using a shield of materials with high electric conductivity in a rotating magnetic field, then the material can be laminated (with insulating layers) in order to reduce losses associated with induced electrical currents in the material.
- Examples on some of the feasible metal materials are as follows: titanium, aluminium, austenitic stainless steel, hastelloy, stellite, talonite, monel, inconel or other nickel-based superalloys, massive or laminated in order to reduce electromagnetic losses. Monel can be completely non-magnetic, also after long term mechanical stress, contrary to many other metals, accordingly monel can be a good choice if minimal magnetism is crucial.
- Examples on some of the feasible non-metal materials are as follows: PEEK, carbon fibre reinforced PEEK, carbon fibre, carbon composites, polyimide, ceramic materials such as zirconiumoxide, and fiber reinforced (carbon, aramid, s-glass, boron fibers) polymers.
- fibers, prepregs or stitched fibres of carbon or other fibers can be wound with pretensioning on a metal or polymer underlayer which again can be arranged on a mandrel, providing a relatively dimensional stable high strength sleeve.
- the mandrel can be removed after production of the shield or the mandrel can remain as part of the shield.
- the mandrel can easily be removed after hardening the composite at elevated temperature if the mandrel is made of a material with high thermal expansion (e.g. aluminium), inside a sleeve of fibre reinforced composite.
- the shield can comprise one or more grooves and/or rifling arranged so as to circulate, move or pump fluid adjacent the groove or rifling and to stabilise the shield by a hydrodynamically created bearing support of the sleeve (prevent oscillations), for a sleeve shaped shield, the groove is preferably shaped as a helix, for a disc shaped shield the groove is preferably shaped as a spiral, if spiral or helix is present on both sides of a shield, then the spiral or helix can be arranged in either opposing or parallel directions on the two sides.
- the groove can be similar in shape to the grooves used for journal bearings, or it can be similar to the grooves used oil cooled clutches (as in automatic transmissions for vehicles), or it can be similar to the rifling in a gun barrel.
- the grooves or rifling can be arranged on the inside and/or outside of a sleeve shaped shield and on either or both sides of a disc shaped shield. If spiral or helix is present on both sides of a shield, then the spiral or helix can be arranged in either opposing or parallel directions on the two sides.
- slightly elliptical cross section shape or lemon bore shape can be used for the sleeve in relation to the annular volume between parts of different rotational speed.
- Said grooves or shapes are arranged in order to enhance circulation of fluid in order to improve cooling.
- grooves may not be required since fluid circulation may be promoted by the other rotating surfaces and from a fluid dynamic view it can be beneficial to have as smooth surfaces as possible.
- the rotating shield relative to its mating parts can comprise bearing surfaces.
- the bearing surfaces can be there for several reasons; a) preventing the shield from rubbing against adjacent components, b) supporting the shield during stand-still, and c) facilitate freely rotation relative to the adjacent parts.
- the sleeve is constrained from axial movement by the annular volume height or length or by machine elements in axial direction, providing a clearance gap sufficient to allow thermal expansion of the sleeve, and the sleeve is dimensioned so that on rest, at low ambient temperature, it has an internal clearance gap sufficient to allow rotation about the internal rotor or stator and at maximum operation speed and temperature it has an external clearance gap sufficient to allow rotation within the annular volume of the external rotor or stator or housing.
- the optimum clearance gap on either side of the sleeve depends on the viscosity of the fluid. 0,5 - 2,0 mm is considered suitable for water-filled machines, however, additional gap for differences in thermal expansion between the sleeve and the inside and outside equipment should be provided. Additional clearance or arrangements for installation can also be preferable.
- FIG. 1 , 2 and 3 illustrating a unit of the invention, two shields for a unit of the invention and a further shield for a unit of the invention, respectively.
- Figure 1 and figure 2 illustrate a unit of the invention with a during operation rotating rotor 1 , a during operation rotating shield 2 and a non-rotating stator 3.
- the shield and its top and bottom plates are one body with liquid circulation holes.
- the shield consists of two concentrically arranged sleeves, typically rotating with approx. 2/3 and 1/3 of the rotor's speed.
- Figure 3 illustrates a shield with helical rifling or groove pattern.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Braking Arrangements (AREA)
- Dynamo-Electric Clutches, Dynamo-Electric Brakes (AREA)
- Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
Abstract
The invention provides a liquid filled, fast rotating unit, such as an electric motor, a mechanical or a magnetic coupling, distinctive in that the liquid filled unit comprises at least one rotating shield arranged between surfaces of different rotational speed.
Description
DRAG REDUCER
Field of the invention
The present invention relates to liquid filled machinery, with parts rotating with so high velocity that hydrodynamic friction reduces the efficiency of the machine to a significant degree. The machine can be for example electric motors, pumps, compressors, torque converters, mechanical couplings, brakes, flywheels, mechanical couplings, magnetic couplings and magnetic gears. "Couplings" is here meant to include clutches, torque limiters, flexible joints, as well as rigid couplings. More specifically, the invention relates to reduction of hydrodynamic friction in equipment of the mentioned type, particularly embodiments thereof for use subsea.
Electric motors for use in hybrid-electric and fully electric vehicles use are often partially oil filled (e.g. as in Toyota's Prius and GM's Volt/Ampera) and they operate over a wide speed range. The invention might also be applicable to these.
Further application might be within the field of power generation, i.e. enclosed hydro power generators and turbines, generators in wave and tidal power plants.
Electric motors in cooling compressors (as in refrigerators, air conditioning and also heat pumps) are also applicable, so are also hydraulic power-packs, in particular when an electric motor and pump/compressor are placed together inside a fluid/liquid filled sealed compartment.
Background of the invention and prior art
For use subsea, electric motors are according to state of the art liquid filled, the liquid is typically oil or a mixture of glycol and water. The liquid filling reduces the risk for short circuiting (in case of being filled with oil), provides or contributes to cooling and lubrication and facilitates pressure compensation.
Liquid filled motors for pumps of size, effect and pressure head feasible for pressure boosting of petroleum liquid and multiphase from petroleum wells and other sources are in practice limited to a rotational speed of about 4000 rpm. At higher speed, the frictional losses and heat become a severe and limiting problem. Accordingly, higher rotational speed, which is beneficial for
compressors and pumps, can be impossible or difficult to achieve. Mechanical and magnetic couplings, such as mechanical or magnetic gears, are also limited with respect to rotational speed, for similar reasons. Creation of vortices and turbulence in the liquid in the volume between rotating parts are assumed to be a significant contribution to the hydrodynamic losses.
As a result, for liquid filled equipment having rotational speed up to the practical limit, the cooling system must be comprehensive and of high capacity, and a comprehensive coolant supply can be required. At locations subsea, often tens or even hundreds of kilometers away from topside installations or shore, this represents severe challenges and high cost.
The objective of the invention is to provide a solution to the above mentioned limitation, in order to mitigate the problems and challenges and extend the practical speed limit for liquid filled motors, couplings and other units.
Summary of the invention
The invention provides a liquid filled, fast rotating unit, such as a motor, a mechanical or a magnetic coupling, distinctive in that the liquid filled unit comprises at least one rotating shield arranged between surfaces of different rotational speed. During operation of the unit, the shield rotates at an
intermediate speed compared to the adjacent machine elements. The shield may be free rotating (i.e. driven by the hydrodynamic drag), or there may be a kinematic link enforcing the intermediate speed.
The term rotational speed covers stationary parts to parts of maximum rotational speed, such as the gap between a stationary stator and a rotor, and the gap between a rotor and a stationary housing. A freely rotating shield will typically rotate at a speed in between the rotational speeds of the adjacent
surfaces of the adjacent objects, for a shield arranged between a stator and a rotor the shield is expected to rotate at about half the rotational speed of the rotor. The hydrodynamic losses depend on the speed of the liquid by a power factor of approximately 3. The shield provides two volumes of half difference in relative speed, resulting in about 1/8 of the original loss in each of the two volumes .assuming that the gaps between the sleeve and the stator/rotor are equal to what is was before the sleeve was introduced. The sum of losses for both volumes (both sides of sleeve) will in such a case be reduced to
approximately 25%. The loss will however in a realistic application be reduced to 25 - 50% depending on the selected gap sizes. If using two or three layers of rotating shields, the sum of losses will be reduced to respectively approx. 1 1 % and 7% depending on selected gap sizes. Further tests have shown that the torque is reduced by approx. 50% and the pressure drop caused by the gap flow between the rotary and stationary parts is reduced with approx. 25% with introduction of such a sleeve in the gap compared to having no such sleeve.
The technical effect is that the dimensions of the full length or extent of the cooling system and supply chain can be reduced accordingly or the maximum rotational speed and pressure head can be increased, or energy for operation is reduced due to reduced hydrodynamic loss. The shield allows a higher maximum rotational speed for a specific demand for cooling, making liquid filled motors and couplings and gears more feasible for multiphase pump and compressor motors. In a preferable embodiment the shield is a tube section or sleeve arranged between the rotor and stator, rotor and housing, rotor and shaft, rotor and barrier wall or between any other rotational parts of cylindrical shape. The radial gap between said parts forms an annular volume into which the sleeve is arranged so as to rotate freely in the gap.
In another preferable embodiment, the shield is a disc or plate arranged between the rotor and stator, or rotor and housing, or in any other axial gap between rotating parts forming a disc shaped volume. This embodiment is
relevant for axial couplings, axial motors and generators having rotors with high aspect ratio of diameter vs length.
Preferably the unit is an electric motor driving a subsea pump or compressor and the shield is a sleeve arranged between the stator and rotor and preferably also a sleeve arranged between the rotor and housing if the rotor is external to the stator. In other embodiments, the sleeve is arranged in the annular gap between any rotational parts of tubular shape, the unit can be a motor of different type than an electric motor, such as a hydraulic motor, or other units.
Preferably the shield is made of a non-ferromagnetic metal, polymer, composite material or ceramic material, if the shield is for arrangements in gaps with a rotating magnetic field. If there is no magnetic coupling between the rotating surfaces, the shield can be made of a ferromagnetic material (and with less resistivity) since there is no magnetic coupling for which magnetic losses can occur. When using a shield of materials with high electric conductivity in a rotating magnetic field, then the material can be laminated (with insulating layers) in order to reduce losses associated with induced electrical currents in the material.
Examples on some of the feasible metal materials are as follows: titanium, aluminium, austenitic stainless steel, hastelloy, stellite, talonite, monel, inconel or other nickel-based superalloys, massive or laminated in order to reduce electromagnetic losses. Monel can be completely non-magnetic, also after long term mechanical stress, contrary to many other metals, accordingly monel can be a good choice if minimal magnetism is crucial. Examples on some of the feasible non-metal materials are as follows: PEEK, carbon fibre reinforced PEEK, carbon fibre, carbon composites, polyimide, ceramic materials such as zirconiumoxide, and fiber reinforced (carbon, aramid, s-glass, boron fibers) polymers. However, fibers, prepregs or stitched fibres of carbon or other fibers can be wound with pretensioning on a metal or polymer underlayer which again can be arranged on a mandrel, providing a relatively dimensional stable high strength sleeve. The mandrel can be removed after production of the shield or the mandrel can remain as part of the shield. The mandrel can easily be removed after hardening the composite at elevated temperature if the mandrel
is made of a material with high thermal expansion (e.g. aluminium), inside a sleeve of fibre reinforced composite.
Production of the shield can however take place by casting, milling, machining, extrusion and/or grinding using traditional methods, there are several options both with respect to choice of material, design and method of fabrication, all of which will be more or less readily available for the person skilled in the art from textbooks and from suppliers and fabricators.
The shield can comprise one or more grooves and/or rifling arranged so as to circulate, move or pump fluid adjacent the groove or rifling and to stabilise the shield by a hydrodynamically created bearing support of the sleeve (prevent oscillations), for a sleeve shaped shield, the groove is preferably shaped as a helix, for a disc shaped shield the groove is preferably shaped as a spiral, if spiral or helix is present on both sides of a shield, then the spiral or helix can be arranged in either opposing or parallel directions on the two sides.
The groove (rifling) can be similar in shape to the grooves used for journal bearings, or it can be similar to the grooves used oil cooled clutches (as in automatic transmissions for vehicles), or it can be similar to the rifling in a gun barrel. The grooves or rifling can be arranged on the inside and/or outside of a sleeve shaped shield and on either or both sides of a disc shaped shield. If spiral or helix is present on both sides of a shield, then the spiral or helix can be arranged in either opposing or parallel directions on the two sides. In addition or alternatively, slightly elliptical cross section shape or lemon bore shape can be used for the sleeve in relation to the annular volume between parts of different rotational speed. Said grooves or shapes are arranged in order to enhance circulation of fluid in order to improve cooling. However, depending on the shape and smoothness of the rotating surfaces on either side of the sleeve, grooves may not be required since fluid circulation may be promoted by the other rotating surfaces and from a fluid dynamic view it can be beneficial to have as smooth surfaces as possible.
The rotating shield relative to its mating parts (typically a rotor and a stator, possibly other rotating shields) can comprise bearing surfaces. The bearing surfaces can be there for several reasons; a) preventing the shield from rubbing
against adjacent components, b) supporting the shield during stand-still, and c) facilitate freely rotation relative to the adjacent parts.
Preferably the sleeve is constrained from axial movement by the annular volume height or length or by machine elements in axial direction, providing a clearance gap sufficient to allow thermal expansion of the sleeve, and the sleeve is dimensioned so that on rest, at low ambient temperature, it has an internal clearance gap sufficient to allow rotation about the internal rotor or stator and at maximum operation speed and temperature it has an external clearance gap sufficient to allow rotation within the annular volume of the external rotor or stator or housing. The optimum clearance gap on either side of the sleeve depends on the viscosity of the fluid. 0,5 - 2,0 mm is considered suitable for water-filled machines, however, additional gap for differences in thermal expansion between the sleeve and the inside and outside equipment should be provided. Additional clearance or arrangements for installation can also be preferable.
Figures
The invention is illustrated with Figures 1 , 2 and 3, illustrating a unit of the invention, two shields for a unit of the invention and a further shield for a unit of the invention, respectively.
Detailed description
Figure 1 and figure 2 illustrate a unit of the invention with a during operation rotating rotor 1 , a during operation rotating shield 2 and a non-rotating stator 3. The shield and its top and bottom plates are one body with liquid circulation holes.
In figure 2 the shield consists of two concentrically arranged sleeves, typically rotating with approx. 2/3 and 1/3 of the rotor's speed.
Figure 3 illustrates a shield with helical rifling or groove pattern.
Claims
1 .
Liquid filled, fast rotating unit, such as a motor, a mechanical or a magnetic coupling, c h a r a c t e r i s e d i n that the liquid filled unit comprises at least one rotating shield arranged between surfaces of different rotational speed, the shield rotating at intermediate speed compared to the adjacent machine elements.
2.
Unit according to claim 1 , wherein the rotating shield is a tube section or sleeve arranged between the rotor and stator, rotor and housing or rotor and shaft or barrier wall, in a radial gap forming an annular volume.
3.
Unit according to claim 1 , wherein the rotating shield is a disc or plate arranged between the rotor and stator, or rotor and housing, in an axial gap forming a disc shaped volume.
4.
Unit according to any one of claim 1 -2, wherein the unit is an electric motor driving a subsea pump or compressor and the rotating shield is a sleeve arranged between the stator and rotor and preferably also a sleeve arranged between the rotor and housing if the rotor is external to the stator.
5.
Unit according to any one of claim 1 -4, wherein the rotating shield is made of a non-ferromagnetic material, preferably chosen amongst: titanium, austenitic stainless steel, aluminium, hastelloy, stellite, talonite, monel, inconel or other nickel-based superalloys, PEEK, carbon fibre reinforced PEEK, carbon fibre,
carbon fibre reinforced polymer, carbon composite, polyimid, ceramic material, fiber reinforced polymers or other proper non-metallic materials.
6.
Unit according to any one of claim 1 -4, wherein the shield comprises one or more grooves and/or rifling arranged so as to circulate, move or pump fluid adjacent the groove or rifling and to stabilise the shield by a hydrodynamically created bearing support of the sleeve (prevent oscillations), for a sleeve shaped shield, the groove is preferably shaped as a helix, for a disc shaped shield the groove is preferably shaped as a spiral, if spiral or helix is present on both sides of a shield, then the spiral or helix can be arranged in either opposing or parallel directions on the two sides.
7.
Unit according to claim 4, wherein the sleeve is constrained from axial movement by the annular volume height or length or by machine elements in axial direction, providing a clearance gap sufficient to allow thermal expansion of the sleeve, and the sleeve is dimensioned so that at stand-still, at low ambient temperature, it has an internal clearance gap sufficient to allow rotation about the internal rotor or stator and at maximum operation speed and temperature it has an external clearance gap sufficient to allow rotation within the annular volume of the external rotor, stator or housing, said clearance gaps are preferably about. 0,5 - 2,0 mm.
8.
Unit according to claim 7, wherein the motor shaft and sleeve are arranged to have vertical orientation, in operation the sleeve rotates at about half speed of the rotor, reducing the hydrodynamic losses due to friction.
9.
Use of a freely rotating shield in liquid filled, fast rotating units, such as a motor, a gear or a magnetic coupling, arranged between surfaces of different rotational
speed, in order to reduce the extent of hydrodynamic losses due to friction and in order to reduce the requirements and cost for cooling system accordingly.
10.
Use according to claim 9, of a sleeve in a subsea motor for a pump or compressor, arranged between a rotor and a stator and between a rotor and a housing if the rotor is external to the stator.
1 1 .
Unit according to claim 1 where the rotating shield comprises several concentric shields rotating at different speeds.
12.
Unit according to claim 1 where the rotating shield and it's mating parts
(typically a rotor and a stator) comprise bearing surfaces.
13.
Unit according to claim 1 where the rotating shield covers at least 10% of the surface area of the rotating parts inside the machine.
14.
Unit according to claim 1 where the shield is free rotating; i.e. it is driven by the hydrodynamic friction on either side of the shield.
15.
Unit according to claim 1 where the shields are made of fibre reinforced polymer (FRP) and the production of the shields involves hardening of the FRP onto a mandrel (form).
16.
Unit according to claim 15 where separation of the shield from the production form (mandrel) is done at a different temperature than the hardening
temperature.
17.
Unit according to claim 6 and 15 where the mandrel (form) imprints major parts of the said pattern (grooves and/or rifling) into the shield.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP14760113.2A EP2965405A1 (en) | 2013-03-06 | 2014-03-05 | Drag reducer |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NO20130341A NO335404B1 (en) | 2013-03-06 | 2013-03-06 | LIQUID, ROTATING UNIT |
NO20130341 | 2013-03-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2014137219A1 true WO2014137219A1 (en) | 2014-09-12 |
Family
ID=51491645
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/NO2014/000025 WO2014137219A1 (en) | 2013-03-06 | 2014-03-05 | Drag reducer |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2965405A1 (en) |
NO (1) | NO335404B1 (en) |
WO (1) | WO2014137219A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107614889A (en) * | 2015-05-29 | 2018-01-19 | 日本电产株式会社 | Air-supply arrangement and dust catcher |
CN108390510A (en) * | 2017-02-03 | 2018-08-10 | 保时捷股份公司 | Method for producing electric power driver and electric power driver |
CN109356935A (en) * | 2018-11-08 | 2019-02-19 | 西北工业大学 | A kind of damping device and drag reduction method based on periodical step cylinder |
Citations (8)
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AT19509B (en) * | 1904-01-29 | 1905-03-10 | Franz Herles | Device for reducing the friction loss in bodies circling in gases or liquids. |
US2609139A (en) * | 1945-06-27 | 1952-09-02 | Kollsman Paul | Fluid friction reducer |
DE2349815A1 (en) * | 1972-10-20 | 1974-05-02 | Ganz Mavag Mozdony Vagon | FLOW MACHINES |
US4084924A (en) * | 1977-02-25 | 1978-04-18 | Alexander Ivanoff | Pump-motor assemblage for circulating a coolant |
EP0492792A1 (en) * | 1990-12-28 | 1992-07-01 | The Nash Engineering Company | Liquid ring pumps having rotating lobe liners with end walls |
DE4434686A1 (en) * | 1993-10-01 | 1995-04-06 | Gen Electric | X-ray tube |
US5828148A (en) * | 1997-03-20 | 1998-10-27 | Sundstrand Corporation | Method and apparatus for reducing windage losses in rotating equipment and electric motor/generator employing same |
US20110002564A1 (en) * | 2009-07-02 | 2011-01-06 | Jan Essensohn | Slide bearing for high rotation speeds of an anode plate |
-
2013
- 2013-03-06 NO NO20130341A patent/NO335404B1/en not_active IP Right Cessation
-
2014
- 2014-03-05 WO PCT/NO2014/000025 patent/WO2014137219A1/en active Application Filing
- 2014-03-05 EP EP14760113.2A patent/EP2965405A1/en not_active Withdrawn
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT19509B (en) * | 1904-01-29 | 1905-03-10 | Franz Herles | Device for reducing the friction loss in bodies circling in gases or liquids. |
US2609139A (en) * | 1945-06-27 | 1952-09-02 | Kollsman Paul | Fluid friction reducer |
DE2349815A1 (en) * | 1972-10-20 | 1974-05-02 | Ganz Mavag Mozdony Vagon | FLOW MACHINES |
US4084924A (en) * | 1977-02-25 | 1978-04-18 | Alexander Ivanoff | Pump-motor assemblage for circulating a coolant |
EP0492792A1 (en) * | 1990-12-28 | 1992-07-01 | The Nash Engineering Company | Liquid ring pumps having rotating lobe liners with end walls |
DE4434686A1 (en) * | 1993-10-01 | 1995-04-06 | Gen Electric | X-ray tube |
US5828148A (en) * | 1997-03-20 | 1998-10-27 | Sundstrand Corporation | Method and apparatus for reducing windage losses in rotating equipment and electric motor/generator employing same |
US20110002564A1 (en) * | 2009-07-02 | 2011-01-06 | Jan Essensohn | Slide bearing for high rotation speeds of an anode plate |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107614889A (en) * | 2015-05-29 | 2018-01-19 | 日本电产株式会社 | Air-supply arrangement and dust catcher |
CN107614889B (en) * | 2015-05-29 | 2020-08-28 | 日本电产株式会社 | Air supply device and dust collector |
CN108390510A (en) * | 2017-02-03 | 2018-08-10 | 保时捷股份公司 | Method for producing electric power driver and electric power driver |
CN109356935A (en) * | 2018-11-08 | 2019-02-19 | 西北工业大学 | A kind of damping device and drag reduction method based on periodical step cylinder |
CN109356935B (en) * | 2018-11-08 | 2020-05-01 | 西北工业大学 | Resistance reducing device and resistance reducing method based on periodic step cylindrical surface |
Also Published As
Publication number | Publication date |
---|---|
NO335404B1 (en) | 2014-12-08 |
EP2965405A1 (en) | 2016-01-13 |
NO20130341A1 (en) | 2014-09-08 |
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