U.S. patent number 3,743,866 [Application Number 05/274,306] was granted by the patent office on 1973-07-03 for rotary curie point magnetic engine.
Invention is credited to Anton Pirc.
United States Patent |
3,743,866 |
Pirc |
July 3, 1973 |
ROTARY CURIE POINT MAGNETIC ENGINE
Abstract
A rotary magnetic engine in which Gadolinium as a transition
material distorts lines of flux in a magnetic field to cause
relative movement between a rotor and a stator. Magnets are mounted
on the rotor and stator, and the Gadolinium metal is disposed in to
form of thin spaced-apart laminae between the poles of certain ones
of the magnets with passageways formed between the laminae for
directing the flow of a coolant fluid. Circuit means is provided to
intermittently direct an electrical current through the laminae
responsive to movement of the rotor with respect to the stator.
This causes the temperature of the laminae to rise above the Curie
point of Gadolinium whereby the lines of flux are released from the
laminae to create magnetic attraction between opposed magnets to
move the rotor. Thereafter the circuit means is opened to permit
the coolant medium to cool the laminae below the Curie point so
that the lines of flux are captured by the fluxdistorting
means.
Inventors: |
Pirc; Anton (San Francisco,
CA) |
Family
ID: |
23047651 |
Appl.
No.: |
05/274,306 |
Filed: |
July 24, 1972 |
Current U.S.
Class: |
310/306;
62/3.1 |
Current CPC
Class: |
H02N
10/00 (20130101) |
Current International
Class: |
H02N
10/00 (20060101); H02n 007/00 () |
Field of
Search: |
;310/9 ;322/2 ;318/119
;60/23 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
elliott, "Thermomagnetic Generator," Journal of Applied Physics,
Vol. 30, No. 11, pp. 1774-1775, Nov. 1959..
|
Primary Examiner: Duggan; D. F.
Claims
1. A magnetic engine to produce mechanical work comprising the
combination of a stator, a carrier structure mounted for movement
with respect to the stator, means mounted on the stator and carrier
structure to create a magnetic field therebetween, said magnetic
field having lines of flux disposed to cause said carrier structure
to undergo said movement with respect to said stator, magnetic flux
distorting means positioned within said field and including a
transition material characterized in having a Curie point above and
below which said material has, respectively, insubstantial and
substantial magnetic response, said flux distorting means including
a plurality of flat laminae disposed in spaced-apart parallel
planes lying substantially within said magnetic field, said
transition material being substantially comprised of Gadolinium
metal, and means to sequentially heat and cool said transition
material above and below its Curie point whereby said lines of flux
are, respectively, released from and captured by said flux
distorting means to create sequential mutual attraction between
said carrier structure and said stator, said heating and cooling
means including means forming fluid flow passageways between
adjacent laminae, and means to direct a coolant medium through said
passageways in direct heat exchange relationship with said
laminae.
2. A magnetic engine as in claim 1 in which said means creating the
magnetic field includes a plurality of magnets each having spaced
apart north and south poles between which said lines of flux
extend, and said laminae are disposed between the poles of
individual magnets.
3. A magnetic engine as in claim 2 in which said heating and
cooling means includes means to selectively direct an electrical
current through said laminae for resistance heating thereof to a
temperature above said Curie point.
4. A magnetic engine as in claim 1 in which said carrier structure
comprises a rotor mounted for rotation with respect to said stator,
and said means creating the magnetic field includes a first series
of magnets mounted on and spaced about the periphery of said rotor,
and a second series of magnets mounted on the stator and spaced
about said first series of magnets, the poles of individual ones of
said second series magnets being arranged to move into radially
spaced registry with the poles of individual ones of said first
series magnets during rotation of said rotor.
5. A magnetic engine to produce mechanical work comprising the
combination of a stator, a carrier structure comprising a rotor
mounted for rotation with respect to the stator, means mounted on
the rotor and carrier structure to create a magnetic field
therebetween including a first series of magnets mounted on and
spaced about the periphery of said rotor, and a second series of
magnets mounted on the stator and spaced about said first series of
magnets, the poles of individual ones of said second series magnets
being arranged to move into registry with the poles of individual
ones of said first series of magnets during rotation of said rotor,
at least a pair of said second series of magnets being mounted at
substantially diametrically opposed positions on said rotor, said
magnetic field having lines of flux disposed to cause said carrier
structure to undergo said movement with respect to said stator,
magnetic flux distorting means positioned within said field and
including a transition material characterized in having a Curie
point above and below which said material has, respectively,
insubstantial and substantial magnetic response, means to
sequentially heat and cool said transition material above and below
its Curie point whereby said lines of flux are, respectively,
released from and captured by said flux distorting means to create
sequential mutual attraction between said carrier structure and
said rotor, said transition material being disposed between the
poles of each of said second series magnets whereby the sequential
heating and cooling thereof above and below the Curie point creates
sequential attraction between the first and second series magnets
to turn said rotor.
6. A magnetic engine as in claim 5 is said first series magnets are
disposed in equal spaced-apart relationship about the periphery of
said rotor, and one of said second series magnets is disposed in
circumferential offset relationship with a diameter passing through
the center of the other of said second series magnets.
7. A magnetic engine to produce mechanical work comprising the
combination of a stator, a carrier structure mounted for movement
with respect to the stator, means mounted on the stator and carrier
structure to create a magnetic field therebetween including two or
more magnets having north and south poles thereof spaced-apart
along the path of movement of said carrier structure, said magnetic
field having lines of flux disposed to cause said carrier structure
to undergo said movement with respect to said stator, magnetic flux
distorting means positioned within said field and including a
transition material characterized in having a Curie point above and
below which said material has, respectively, insubstantial and
substantial magnetic response, said flux distorting means
comprising a plurality of foil strips disposed in laterally
spaced-apart planes extending between associated north and south
poles of each magnet, each of said strips being substantially
formed of Gadolinium metal as said transition material and having a
thickness on the order of 0.001 inches, and means to sequentially
heat and cool said transition material above and below its Curie
point whereby said lines of flux are, respectively, released from
and captured by said flux distorting means to create sequential
mutual attraction between said carrier structure and said stator,
said heating and cooling means including means to selectively
direct an electrical current through said strips to heat the same
above the Curie point together with means to direct a coolant fluid
in heat exchange relationship with said strips to cool the same
below the Curie point.
8. A magnetic engine as in claim 7 in which said flux distorting
means includes grid means disposed between adjacent foil strips,
and said grid means supports said foil strips in planes which are
spaced-apart a distance on the order of 0.03 inches.
9. A magnetic engine as in claim 8 in which said grid means defines
in cooperation with said foil strips a plurality of coolant flow
passageways adapted to direct said coolant fluid in direct heat
exchange contact with substantial surface area portions of the foil
strips.
10. A magnetic engine as in claim 1 in which said carrier structure
is mounted for rotation with respect to said stator, and said
heating and cooling means includes circuit means to direct an
electrical current through said laminae to heat the same above the
Curie point, said circuit means including switch means operating
responsive to the relative position of said carrier structure with
respect to said stator to open the circuit means for said cooling
and to close the circuit means for said heating, said coolant
medium comprising a fluid being directed through said passageways
to cool said laminae below the Curie point while said circuit means
is open.
Description
BACKGROUND OF INVENTION
This invention relates generally to magnetic engines in which
mechanical work is produced by distorting the lines of flux in a
magnetic field. More particularly, the invention relates to
magnetic engines utilizing transition materials characterized in
having a sharp and reversable change in magnetic response in a
relatively narrow temperature range, known as the material's Curie
point.
Various types of magnetic engines have heretofore been proposed in
which the lines of flux in a magnetic field are distorted to create
mechanical work by heating and cooling a flux distorting transition
material above and below the material's Curie point. These known
engines have anumber of limitations and drawbacks and have not been
found to be practical. Thus, previous efforts in this field have
produced magnetic engines which are extremely limited in torque
output in view of the low rotational speeds and weak forces of
magnetic attraction which are produced. Furthermore, previous
designs are relatively inefficient in view of the high energy
transfer to and from the transistion material which is required for
cycling the engine, and in adition to the high operating
temperatures tend to reduce the intensity of the magnetic field.
Accordingly, the need has been recognized for a new and improvied
magnetic engine of the type described which is capable of achieving
higher torque output, higher rotational speeds, and improved
efficiency.
OBJECT AND SUMMARY OF THE INVENTION
It is a general object of the invention to provide a new and
improved magnetic engine producing mechanical work by utilizing the
properties of a transition material adapted to distort the lines of
flux in a magnetic field.
Another object is to provide a magnetic engine of the character
described in which a carrier structure is mounted for movement with
respect to a stator with means on the stator and carrier structure
to create a magnetic field. Magnetic flux distorting means which
includes Gadolinium as the transition material is interposed in the
magnetic field. Means are provided to sequentially heat and cool
the transition material above and below its Curie point to release
and capture, respectively, the lines of flux to cause the carrier
structure to move relative to the stator.
Another object is to provide a magnetic engine of the character
described in which the flux distorting means includes a transition
material formed of relatively thin strips of Gadolinium metal
disposed in spaced-apart laminae separated by a grid forming
coolant flow passagesways. The metal is intermettently heated above
its Curie point by an electrical current responsive to the position
of the carrier structure with respect to stator, and the metal is
cooled below its Curie point by directing a coolant fluid through
the passageways.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a magnetic engine incorporating the
present invention;
FIG. 2 is an axial section view of the engine of FIG. 1; and,
FIG. 3 is a perspective view to an enlarged scale of one magnet and
associated flux distorting means for the magnetic engine of FIGS. 1
and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2 there is disclosed generally at 10 a
magnetic engine including a stator 11 mounted to a suitable
foundation by legs 12, 13, and a carrier structure or rotor 14
mounted for rotation about a vertical axis by suitable ball bearing
assemblies 16, 17 which in turn are mounted within respective end
brackets 18, 19 secured to the stator.
Stator 11 comprises a pair of end plates 21, 22 vertically
spaced-apart by means of four corner posts 23. Means are provided
on the stator to create a stationary magnetic field, and this means
includes an upper series of two U-shpaed permanent magnets 24, 25
mounted by suitable fastners below end plate 21 and a lower series
of two similar U-shaped magnets 26, 27 mounted by suitable fastners
above end plate 22. Both pairs of magnets 24, 25 and 26, 27 are
mounted about the circumference of circular openings 28, 29 formed
in respective end plates 21, 22. Each of these magnets have their
north (N) and south (S) poles facing radially inwardly and in like
circumferential sequence, as shown in FIG. 1. The magnets are
disposed so that the magnet 24 is circumferentially offset
substantially 15.degree. with respect to a diameter passing through
the center of the opposite magnet 25. Preferably the magnets 26, 27
are of a material providing a strong magnetic flux or coercive
force, e.g., Samarium Colbalt material or one of the Alnicol alloys
of Aluminum and Nickel. Alternatively, sutiable electromagnets
could be used in place of the described permanent magnets.
Rotor 14 comprises a shaft 31 carrying a pair of axially spaced
circular plates 32, 33 mounted within lower stator plate opening 29
and a similar pair of axially spaced circular plates 34, 35,
mounted within upper stator opening 28. The means creating a
magnetic field further includes a lower series of U-shaped
permanent rotor magnets shown as six magnets 37, 38, mounted by
suitable fasteners between the lower rotor plates 32, 33 and
circumferentially spaced so as to turn with the rotor in a path
disposed radially inwardly of the two stator magnets 26, 27. A
similar upper series of six U-shaped permanent rotor magnets 40-45
are mounted by suitable fasteners between the upper rotor plates
34, 35 and these magnets are also circumferentially spaced so as to
turn with the rotor in a path disposed radially inwardly of the
upper stator magnets 24, 25. The upper and lower series of rotor
magnets have their north (N) and south (S) poles facing radially
outwardly and in like circumferential sequence, as shown in FIG. 1.
Preferably the rotor magnets are of a material similar to that
described for the stator magnets whereby a strong magnetic flux is
provided, or alternatively suitable electromagnets could be
provided for use as the rotor magnets.
Magnetic flux distorting measn is provided between opposite poles
of each of the stator magnets 24, 25, 26, 27. This flux distorting
means includes a transition material characterized in having a
sharp and reversable change in magnetic response in a relatively
narrow temperature range, known as the material's Curie point. As
the transition material is heated and cooled above and below the
Curie point the material undergoes a second order transition in
magnetization such that the material has, respectively,
insubstantial and substantial magnetic response to release and
capture lines of magnetic flux.
Applicant's invention utilizes the preferred metal Gadolinium as
the transition material in the form of a plurality of relatively
thin foil strips 47, 48 disposed in transversly spaced-apart
laminae extending between opposite poles of each stator magnet, as
best illustrated in FIG. 3 for the typical stator magnet 24,
Gadolinium is characterized in having (with a purity on the order
of 99,9%) a favorable Curie point of 16.degree. Celsius together
with a relatively high magnetic flux saturization. The metal
Thulium has similar favorable properties as a transition material,
but Gadolinium is preferred in view of its greatr availability and
cost advantages. The use of Gadolinium, or Thulium where such is
available, as the transition material in the manner described makes
it possible to develop relatively higher rotational speeds and
torque for the rotary engine through greater work efficiency. While
other transition materials are known, such as Ferromagnetic
elements and alloys, these known materials have Curie points which
are either too high or too low for practical use, and/or their
magnetic saturation properties are so low that strong magnetic
fields cannot be employed to achieve the high magnetic attraction
forces required for the desired torque output and speed. In
addition, a transition material having a relatively high Curie
temperature tends to lose its saturation magnetization when heated
to its Curie point, e.g. Iron which has a Curie point of
770.degree. Celsius, and in such case work efficiency would be
compromised in that objectionable amounts of energy would be lost
when heating the material to these high temperatures.
As illustrated in FIG. 3 the Gadolinium laminae are supported in
spaced-apart relationship by means of a plurality of grid elements
48 formed of a suitable material such as a synthetic polymer, e.g.,
epoxy, having a relatively high heat transfer coefficient, Each of
the grid elements 48 is formed with a plurlaity of vertically
extending channels or grooves 49 which, in cooperation with the
surfaces of an adjacent pair of laminae, define coolant fluid
passageways. Each grid element comprises a flat, central web
portion and a plurality of vertically extending ribs projecting
outwardly from opposite sides of the web portion into contact with
the laminae. This configuration insures that the coolant fluid
flows in direct heat exchange relationship with substantial surface
area portions of the foil strips. The coolant passageways which are
thereby formed preferably have a cross section configuration which
achieves maximum heat transfer for cooling the laminae, e.g., a
cross section width of 0.025 inches and height of 0.125 inches with
surface-to-surface spacing between adjacent laminae of 0.062
inches.
The means for cooling the laminae below the material's Curie point
preferably includes a suitable coolant fluid such as liquid
nitrogen, although other coolants such as cold water, or a gas such
as Freon 14 (tetrafluoromethane) they also be employed. The liquid
nitrogen is stored at approximately 146.degree. Kelvin within
suitable tank 51 and is directed through the grid passageways 49 by
a suitable pump 52 connected with the tank through conduit 53 and
discharging through outlet 54. An upper manifold 56 directs coolant
through piping 57 and into a pair of distributor shrouds 58, 59
mounted above the grids and laminae located between the two upper
magnets 24, 25. Each of the shrouds 58, 59 open downwardly to
direct coolant downwardly through the grid passageways for exhaust
to the atmosphere through outlets 61,62. Alternatively, the exhaust
nitrogen may be recycled back to tank 51 through a circuit, not
shown, incorporating suitable nitrogen liquefaction apparatus. A
lower manifold 63 directs a portion of the nitrogen through piping
64 and into a pair of distributed shrouds 66, 67 mounted above the
grid and laminae structure located between the two lower magnets
26, 27. The lower distributor shrouds also open downwardly to
direct coolant downwardly through the passageways for exhaust
through outlets 68, 69, or through an alternate circuit for
liquefaction and recycle back to tank 51.
The transition material is sequentially heated above its Curie
point preferably by electrical circuit means 71 adapted to
intermittently direct a flow of current through the foil strips 47
for resistance heating. Alternatively, other suitable heating means
such as radiant energy, electrical induction, or a heat exchange
medium such as a suitable high temperature gas may be employed.
Resistance heating is perferred in that it achieves relatively fast
heating of the laminae with relatively low power requirements to
achieve faster cycling and higher speeds at improved efficiency.
Each of the foil strips 47 is formed into a sinuous configuration
with preferred dimensions having a thickness in the range of
0.001-0.004 inches, a width of each strip leg of 0.120 inches and
with spacing between the legs of 0.005 inches. In the illustrated
embodiment eight such laminae are assembled in separate stacks for
each of the stator magnets.
A suitable source of direct current electrical power 72 is
connected through a conductor 73, a cam operated switch 74 and a
conductor 76 with an upper end of a side laminae 47 for the magnet
25, with the lower end of the opposite side laminae being connected
through a conductor 77 with the power source. As best illustrated
in FIG. 3 the lower ends of alternate pairs of the laminae are
electrically interconnected by short conductors 78 while the upper
ends of offset alternate pairs of laminae are similarly
interconnected by short conductors 79 so that all laminae for the
magnet 25 are in series connection. Similarly, the laminae for the
opposite magnet 24 are connected in series with power source 72
through a conductor 81, a cam operated switch 82 and a conductor 83
leading to an end of one laminae, with the opposite end laminae
connected with the power source through conductor 84. The laminae
for the lower pair of stator magnets 26, 27 are connected with
power source 72 for intermittent operation through similar circuit
means, not shown. The cam operated switches 74, 82 include normally
open contacts 86, 87 which are operated to close the respective
circuits for heating the associated laminae responsive to movement
of six cam lobes 88-93 mounted on rotor plate 35 and projecting
radially outwardly therefrom. The cams are positioned with respect
to the rotor magnets so that the switches are operated for closing
the respective circuits at the predetermined rotor positions where
the laminae are to be heated for release of the flux from the
stator magnets. The length of the cam lobes is selected so that the
switches are closed for a predetermined time interval, as
determined from heat transfer and resistance heating calculations,
which is sufficient to elevate the temperature of the laminae above
its Curie point. As the cams move out of contact with the switch
contacts the circuits are again opened so that the continuous flow
of coolant fluid begins to reduce the temperature of the laminae.
During the time interval at which the temperature is above the
Curie point and the magnetic flux is released, like north (N) and
south (S) poles of opposing rotor and stator magnets are
magnetically attrated to impart torque to the rotor. As the poles
of the magnets approach each other the cooling cycle has progressed
sufficient to reduce the temperature of the laminae below the Curie
point so that the flux is again captured and the magnetic
attraction between the magnets becomes insubstantial. This permits
the momentum of the moving rotor to carry the rotor magnet past a
dead center position with respect to the stator magnet and move the
next successive rotor magnet into the influence of the magnetic
field of the stator magnet 24. Continued rotation of the rotor is
also assured by the offset angular displacement of the stator
magnets such that the centers of one of these magnets lies along a
radius disposed substantially at an angle of 15.degree. with
respect to the diameter passing through the center of the opposite
stator magnet. This configuration provides for one pair of stator
and rotor magnets to be in mutual attraction for imparting driving
torque while no torque is being developed by the opposite pair of
rotor and stator magnets.
The use and operation of the invention is as follows. Assume that a
liquid nitrogen coolant is provided within tank 51 at a temperature
on the order of 145.degree. Kelvin. The coolant is continuously
pumped through the upper and lower manifolds 56, 63 and down
through the passageways between the Gadolinium laminae 47 until the
metal's temperature is below its Curie point, thereby releasing the
magnetic flux from each of the stator magnets 24, 25. With the
rotor turning clockwise, as viewed in FIG. 1, the rotor magnet 42
moves through an arc of circular travel which carrys its associated
cam lobe 89 to a position bearing against and closing contacts 86
of switch 74. This completes the circuit through the laminae
between the poles of magnet 24 to initiate resistance heating.
While the Gadolinium is heated above the Curie point magnet 42 is
attracted to stator magnet 24 and a driving torque is imparted to
the rotor, with power being taken from shaft 31 by suitable means
such as a belt seated within pulley 94. The heating phase continues
for a predetermined circular arc of travel until the poles of these
two magnets are in substantial registry. At this point cam lobe 89
moves away from switch contacts 86 to open the circuit and
terminate heating so that the coolant flow again rapidly cools the
laminae associated with stator magnet 24 below the Curie point.
This causes the flux of the stator magnet to be captured by the
Gadolinium so that the magnetic attraction with magnet 42 becomes
insubstantial permitting the rotor to be carried by its momentum
through a further arc of travel sufficient to bring the next
successive rotor magnet 41 and cam 88 into position for a
repetition of the heating phase so that this magnet is similarly
attracted to stator magnet 24. The opposite stator magnet 25
similarly attracts successive rotor magnets, although the operation
is out of phase from that of magnet 24 to achieve an overlap in
driving torque.
While the embodiments herein are at present considered to be
preferred, it will be understood that numerous variations and
modifications may be made therein by those skilled in the art, and
it is intended to cover in the appended claims all such variations
and modifications as fall within the true spirit and scope of the
invention. I claim:
* * * * *