Note: Descriptions are shown in the official language in which they were submitted.
MAGNETIC DRIVE HAVING A LIQUID-COOLED HIGH TORQUE AND HIGH POWER
APPARATUS
CROSS REFERENCE TO RELATED APPLICATIONS.
This application claims priority from U.S. application number 16909989 filed
on 23 June 2020.
BACKROUND OF THE INVENTION
The present invention relates to an improvement over the prior art more
particularly set forth in
U.S. patent 7294947, and its related patents in other jurisdictions, wherein,
said prior art was
directed to a rotational magnetic torque transfer device utilizing two coaxial
cylinders
overlapping one another wherein one cylinder contains a row(s) of pemianent
magnets and the
other cylinder contains a ring(s) of electroconductive material, but the
problem was that said
prior art had a maximum power transfer limit since the induction rotor bars
were atmospherically
air cooled, said air cooling causing both the induction rotor bars and
magnetic circuit materials
to reach a temperature that would break down the magnetic characteristics of
the materials above
a certain power transfer rating point. The challenge is to develop a modified
geometric
arrangement and structure for the device that would allow for direct liquid
injection cooling
within said coaxial cylinders without increasing magnetic circuit reluctance
or electrical
conductor short circuits within said device. The prior art was limited to less
than 1000 KW
power transfer, otherwise the internal operating temperature of the unit would
cause the
permanent magnets' field to fail.
It is desirable to devise a liquid cooled permanent magnet excited mechanism
for transmitting
variable torque in drive applications. Specifically, there is a need to couple
constant speed
devices such as motors or engines to high power variable output speed and
torque devices such
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as pump impellers, fans, propellers, wheels, etc. As set forth in the prior
patent US 7294947, this
devices specific individual electroconductive rotor bar geometry together with
the analogous
matched permanent magnets similar geometry placed directly opposite said rotor
electro-
conductive bars taken together create a torque transfer device that is not a
traditional eddy
current device, Eddy current devices produce circular-like eddy currents in
relatively wide
electro-conductive materials. The improvement over the US 7294947 device's
specific narrow
rotor electroconductive rotor bars and narrow cross-section permanent magnets
rests in devising
a way to maintain this non-eddy current rotor bar efficiency, but yet develop
a way to quickly
remove the high heat generated a high power transfers in said electro-
conductive bars, in a
manner that will maintain the prior art's (US 7294947) efficient magnetic
circuit
The invention discloses and claims improvements that allow very large power
transfers through
direct liquid injection into the electroconductive bars, then said liquid
exiting directly and
impinging upon the magnetic bar rotor, said liquid not interfering with the
permeability of the
magnetic field or magnetic circuit.
The described apparatus is a device that uses permanent magnets and conductors
arranged in an
optimal manner to generate the magnetic flux in a power transmission drive,
together with direct
liquid injection for both rotors cooling. The embodiments described utilize a
mechanical means
for changing the flux density between two rotating components to vary the
torque transmitted by
and thereby the output speed of the apparatus
BRIEF SUMMARY OF THE INVENTION
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As was disclosed in the prior art patent US 729947, the present invention
utilizes permanent
magnets to transmit variable or fixed torque between two rotating elements.
The aforesaid
permanent magnets are located on only one of the two rotating elements (also
referred to as
"rotors" or "rotary members"), and the other rotating element in a particular
embodiment does
not contain permanent magnets but does have so-called "el ectro-conductive"
elements. In
addition, so-called "magnetically permeable" materials are also contained on
the said non-
permanent magnet rotors, said magnetically permeable materials comprising
substances that
allow magnetic flux penetration. The torque between the aforesaid two rotating
elements is
adjusted by varying the amount of magnetic flux passing between the elements
by varying the
extent to which the elements are axially overlapped. In a preferred embodiment
of the apparatus,
two concentric cylinders, one containing one or more rows of permanent
magnets, is moved
axially in order to progressively axially overlap a second cylindrical element
containing electro-
conductive elements and magnetically permeable elements, but not containing
permanent
magnets. This progressive axial overlapping of the two cylinders allows
variation in the amount
of magnetic flux intersecting the two concentric cylinders. This causes the
amount of induced
electrical current in the cylinder containing the electro-conductive elements
to vary, which then
causes the induced counter magnetic forces to vary. The magnetic forces and,
thus, torque
transmitted will vary based on the amount of axial overlap.
Said prior art was only air cooled by atmospheric air existing around the two
rotors. The electro-
conductive rotor has induced current that increases as the relative angular
velocity difference
between the two rotors increases; said current generating heat, thereby
limited the unit to
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transferring approximately 260 KW (at 1,000 ft-lb torque). Therefore, in order
to transfer
thousands of kilowatts of power, a liquid cooling system was devised wherein
said cooling liquid
would travel extremely close to the current-carrying/heat-generating surface
of the electro-
conductive rotor bar, and wherein the amount of liquid flow through each rotor
bar could be
adjusted with threaded end plugs at the end of each el ectro-conductive rotor
bar cooling liquid
channel. Further, in order to cool the surface of the magnet rotors which run
very close to the
inductive rotor bars through a very narrow gap, when said cooling liquid gets
to said flow
adjusting screw plug, the liquid coolant is directed radially to the magnet
rotor so that the liquid
coolant directly impinges upon the surface of the magnet bars. The proposed
invention
overcomes previous limitation of the invention disclosed in US 7294947 in that
there is no limit
to the amount of power that the device can transfer limited only by the
structural strength of the
various materials. There is no longer any limitation due to the heat generated
in the electro-
conductive bars in the electro-conductive rotor. The liquid coolant does not
interfere with the
magnetic field circuit magnetic flux flow nor does said coolant allow internal
short circuits for
the components in and around the electro-conductive elements. Further the
induction rotor
rotation itself acts as a second centrifugal boost pump to assist in
circulating the liquid coolant.
In order to properly regulate the amount of liquid coolant flow needed for
proper cooling, and
not permit excessive liquid cooling flow which would reduce the net power
transfer efficiency of
the unit, the new geometry of the new liquid cooled induction rotor has
adjusting screw plugs at
the end of each electro-conductive rotor bar (504).
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The proposed invention overcomes previous limitations by taking advantage of
new technologies
in magnet materials and provides a stable means of mechanically varying large
amounts of
transmitted torque without the need for large external current controls.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
The drawings constitute a part of this specification and include exemplary
embodiments to the
invention, which may be embodied in various forms. It is to be understood that
in some instances
various aspects of the invention may be shown exaggerated or enlarged to
facilitate an
understanding of the invention.
Description of selected embodiments of the invention included herein are
listed as follows:
FIG. 1 is an isometric view of the exterior of a preferred embodiment of the
invention.
FIG. 2 is an exploded isometric view of FIG. 1.
FIG. 3 is an exploded isometric view of the liquid-cooled electro-conductive
rotor of the
preferred embodiment of the invention.
FIG. 4 is an isometric view of the liquid-cooled electro-conductive rotor.
FIG. 5 is an isometric view of the detail of the channels for cooling liquid
flow immediately
adjacent to and running parallel along the electroconductive rotor bars of
FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
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Detailed descriptions of preferred embodiments are provided herein. It is to
be understood,
however, that the present invention may be embodied in various forms.
Therefore, specific
details disclosed herein are not to be interpreted as limiting, but rather as
a basis for the claims
and as a representative basis for teaching one skilled in the art to employ
the present invention in
virtually any appropriately detailed system, structure or manner.
Referring to FIGS. I though FIG. 5, the preferred embodiment of the invention
is shown and
described as it applies to a liquid cooled high power variable speed drive
application. The two
coaxial rotors [one rotor having axially placed electro-conductive bars (201)
and one rotor
having one axially placed permanent magnet bars (202)] together with their
respective support
bearing cartridge systems [(200 and 203) are shown in an exploded view outside
of their casing
(100). Also, shown is the automatic control system actuator (204) which moves
one of the two
rotors relative to one another to adjust the axial overlap of the two rotors
while they are rotating
to vary the amount of torque and power transferred through the unit. The
embodiment casing
(100) when assembled is fully liquid-tight so as to capture the cooling liquid
that is pumped
through the cooling liquid passages (501) located directly adjacent to the
electro-conductive rotor
bars (504). The bearing support cartridges (200 and 203) are oil lubricated
and cooled and are
sealed from the outside and from the casing so that the oil and the rotor
cooling liquid do not
intermix. The purpose of using magnetically permeable material is to provide a
continuous
magnetic flux path between the magnetic pole faces, thereby allowing optimum
magnetic flux
arrangements to exist. The magnetically permeable material need not be
ferromagnetic.
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The cooling system is a closed system consisting of an external liquid storage
tank, a centrifugal
circulating pump, a heat exchanger to reject the heat picked up in the
magnetic drive unit,
temperature gages, pressure gages, filters, and interconnecting piping. The
cooling liquid may
consist of a mixture of distilled water and a glycol compound.
Said prior art was only air cooled by atmospheric air existing around the two
rotors. The electro-
conductive rotor has induced current that increases as the relative angular
velocity difference
between the two rotors increases; said current generating heat, thereby
limited the unit to
transferring approximately 260 KW (at 1,000 ft-lb torque). Therefore, in order
to transfer
thousands of kilowatts of power, a liquid cooling system was devised wherein
said cooling liquid
would travel extremely close to the current-carrying/heat-generating surface
of the electro-
conductive rotor bar, and wherein the amount of liquid flow through each rotor
bar could be
adjusted with threaded end plugs at the end of each electro-conductive rotor
bar cooling liquid
channel (502 and 503). Further, in order to cool the surface of the magnet
rotors which run very
close to the inductive rotor bars through a very narrow gap, when said cooling
liquid gets to said
flow adjusting screw plug (503), the liquid coolant is directed radially to
the magnet rotor so that
the liquid coolant directly impinges upon the surface of the magnet bars. The
proposed invention
overcomes previous limitation of the invention disclosed in US 7294947 in that
there is no limit
to the amount of power that the device can transfer limited only by the
structural strength of the
various materials. There is no longer any limitation due to the heat generated
in the electro-
conductive bars in the electro-conductive rotor. The liquid coolant does not
interfere with the
magnetic field circuit magnetic flux fl ow nor does said coolant allow
internal short circuits for
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the components in and around the electro-conductive elements. Further the
induction rotor
rotation itself acts as a second centrifugal boost pump to assist in
circulating the liquid coolant.
In order to properly regulate the amount of liquid coolant flow needed for
proper cooling, and
not permit excessive liquid cooling flow which would reduce the net power
transfer efficiency of
the unit, the new geometry of the new liquid cooled induction rotor has
adjusting screw plugs
(502 and 503) at the end of each electro-conductive rotor bar (504)..
While the invention has been described in connection with a preferred
embodiment, it is not
intended to limit the scope of the invention to the particular form set forth,
but on the contrary, it
is intended to cover such alternatives, modifications, and equivalents as may
be included within
the spirit and scope of the invention as defined by the appended claims
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