Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
The present invention relates to a system for tracking
the re]ative movement of the sun and earth for use with a
flash boiler operated steam engine where the principal
heat is supplied by a solar concentrator confined within a
solar energy collector.
There are several prior art devices that utilize solar
heat to operate steam engine devices.
United States Patent No. 1,4~4,932 teaches the use of
a steam engine boiler positioned at the apex of a
parabolic reflector system. This system teaches the
forming of a parabolic surface and a plurality of
different focal points around the surface of the steam
boiler.
There is no means provided for positioning of the
device to ensure maximum heat from the Sun during
Sun/Earth relative movement.
United States Patent No. 1,386,781 teaches a solar
con-_entrator device where Sun tracking is performed by a
20 clock motor mechanism~ -
United States Patent No. 3,8~2,433 teaches a plurality
of curved reflectors positioned to direct solar energy to
a plurality of focal points on a steam generator. The
positioning of the reflectors requires an equal plurality
of optical sensors and sensor-servo mechanisms.
These prior art systems are complicated, inefficient
and economically expensive to produce.
SUMMARY OF T~E INVENTION
The present invention provides a system for tracking
the relative movement of the sun and earth comprising: a
base memberî a positionable platform carried by said base
~,
member; a plurality of light sensors, each light sensor
providing a control signal when exposed to the direct rays
of the sun, said sensors being positioned in a spaced apart
relationship about the periphery of said positionable
platform provicling a first and second pair of diagonally
opposed light sellsors; shieldincJ means pos:itioned adjacent
each of said plurality of light sensors for preventing -the
direct rays of the sun from s-triking more than one light
sensor of each pair of ligh-t sensors at any given time; a
first positioning means responsive to said control signals
from said first pair of light sensors for providing
directional rotation of said positionable platform with
respect to said base member along a first path of travel
between physical restraints; and a second positioning means
responsive to the control signals from said second pair of
light sensors for providing directional rotation of said
positionable platform with respect to said base member
along a second path of travel between the physical
restraints; said first and second positioning means include
control signal interruption means for stopping the movements
of said positionable platform along said first and second
paths of travel prior to reaching said physical restraints.
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DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a partially cutaway side view of the
apparatus of the invention;
FIGl]RE 2 is a plan view o:E the reElective surface
of the solar concentrator of the invention;
~ IG[JRE 3 :is a partial:l.y cutaway v:iew o:E the
apparatus o:E the inventioJI taken along lines 3-3 of Figure 2;
FIGURE 4 is a diagrammatic view o:E the electrical
wiring of the solar tracking mechanism of the invention;
FIGUR.E 5 is a plan view, partially in phantom~ of
the injector pumps and their operating mechanism; and
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FIGURE 6 is a side view of the Figure 5 showing
further including the valves and their operating mechanism.
Description of the Preferred Embodimen-t
The same reference numerals are used throughout the
Figures and specifications to depict the same element or part.
ReferL~ing now specifically to E'igures 1, 2 and 3, a
combination solar light energy collector and concentra-tor 10 is
shown. The apparatus is suppor-ted by as base 12, 12a at-tached
to a surface positioned on the Earth 13, an example would be a
support member buried in the ground to a sufficient depth and
having sufficient mass to easily support the apparatus 10. The
base 12a supports a motor 14 which drives a gear 16 attached to
the motor shaft. Gear 16 drives a larger semi-circular gear 18.
The gear 18 is fixedly attached to shaEt 20 which is fixedly
attached to the collector bracketry 22. Shaft 20 is rotatably
attached to the base member 12 thus allowing the base free
rotational movement relative thereto.
Pivotly attached to bracketry 22 is the collector
bottom member 24. The bottom member 24 is allowed to pivot with
respect to base member 12, 12a at its pivotal attachment points
26, 28. The collector further includes side members 30 and end
members 32. The lid 34 of the collector is constructed of a
light admitting material, such as, but not limited to, glass
or plexi-glass. The lid, sides, ends and bottom make up an
enclosure for the collection of solar energy. Insulation (not
shown) is used to contain the heat within the collector.
A bracket 36 fixedly secured to shaft 20 supports a
second motor 38. The rotation of motor 38 drives a gear 40.
A gear rack 42 is pivotly attached at its upper end 39 to the
collector bottom 24. The opposite end of the rack 42 is held
in sliding engagement by bracket 45 which is free to pivot with
respect to gear 40 and allows rack 42 to freely move therein
when the gear 40 i5 caused to rotatate. It can be readily seen
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that when the motor rotates, the rack will translate causing
the co:Llector to tilt downwardly from its Figure 1 and 3
position. Along arrow 43 within the limits of the length of
-the gear rack 42.
Posi-tioned within the upper portion of the collector
are two cyllncle:r~ 44 which contain pistons 46 sli.dably engaged
thereln. The pi.stons ~re each connected to a connec~ing rod 48
by a conventional pis-ton pin ~9 (see Figure 5) so that the
connectiny rod is Eree to move laterally with respect to the
longitudinal movement of the piston. The ends of the connecting
rods remote from their piston attached ends are pivotly connec-
ted to a central disk 50 (see the various figures). The disk
50, in some instances, will be required to have sufficient
mass to act in the manner of a fly wheel.
It can be readily seen that as the pistons move wi-thin
their respective cylinders, the disk S0 will rotate.
The disk 50 is secured to the end of a drive sha:Et
52 which passes through a 51ip guide 53 and is attached to a
generator 55 for the production of electricity as the pistons
20 move. It should be understood that drive shaft 52 may be util-
ized.to perform any type of useful wor~ and is not limlted to
the production of electricity.
The cylinders are supported by the lower surface 24
by any convenient manner so as to block as little of the Sun's
rays striking the reflective surfaces as practical. Brackets
51 are an example of how this may be accomplished.
The generator 55 is secured either to the bracketry
22, -the bottom 24 of the collector or through a supporting
bearing on shaft 52, so that it can tilt or turn with the
collector panel when motors 38 and 14 are ener~ized.
At one end of cylinders 44 is positioned flash steam
boiler 54. A pump 56 for pumping the pre-heated water or any
suitable expandable fluid through the injectors 41 (shown in
one variation~ is interconnected to each of the two flash
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steam boilers throu~h high pressure condui-t 58,60. The inlet to
the pump 56 is connected to a source of preheated water (herein~
after discussed) through conduit 62. The output of the pump
supplies water under increased pressure to a conventional
injector ~11, such as those used in the diesel encJine ar-t, which
injects this wa-ter :into the Elash steam boiler 5~.
A plurallty oE f:la-t rec-ti-linear reflective surfaces
6~ are supported by and cover the inner surEace of bottom 2~.
The reflective surfaces are positioned and held in place so that
each will reflect the light of the Sun shining thereon to a
single focal point 66 on the lower surface of the flash steam
boiler 54. It sllould be noted that the reflective surfaces
shown are of sufficient area quantity to be equally divided
between two focal points to operate two flash steam boilers 54.
The reflective surface may be glass mirrors, however,
the invention is not limited in this manner as any suitahle re-
flective surface may be utilized equally as well to practice
the invention.
The source of preheated water supplied to the pump
56 may be provided by the coil of conduit 68 positioned within
the aforementioned collector, from any external heating means
(not shown) or from a combination of the coil of conduit 68
and additional heat from an external source. It should be
apparent that the heated water from the coil of conduit 68 may
be used to supply heat requirements separate from the engine,
a~ a conventional solar heater. The engine exhaust steam may
be vented to atmosphere through condui-t 70 in an open cycle
system where the input to the coil of conduit 68 is supplied
from an external source of water. Ideally, the engine steam
exhaust is utilized in a closed system wherein the steam passes
through an external heat exchanger where it is used for the
heating of building, operating refrigeration apparatus or the
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like. The removal of heat from the steam in this manner acts
as a condenser to cool the steam back to a water which is then
returned to one end of -the coil conduit 68, is re-heated, and
again supplied to pump 56 through conduit 62 (see Figure 3).
If, in a closed system, the use o:E the exhaust heat is
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not desired, a sufficiently long conduit 70 would be requiredto lower the steam temperature or a conventional condesner
may be employed, in series between the engine exhaust and
the coil of conduit 6~.
Referring now to Figures 1-~, on each side 30, eAYternal
o:f the collector, are positioned light sens:ing elemcnts 72a,
72b, on each end 32 are positioned a pa.ir of sensors 72c and
72d, in some appli.cations a pair of sensors 72c and 72d may be
be required (see Figure 4). These sensors may take many forms,
such as~ but not limited to, selenium photo cells, catalog
number 276-115 and light activated silicon controlled
recitfiers, catalog number 276-1095, both are manufactured
by Archer for Radio Shack Inc., or tlle like. ~eferring now
speci:Eically to Figure 1, a shield 74 is positioned ad-
jacent to the sensors 72c and 72d preventing direct Sun light
from the opposite side of the collector from stri~ïng their
light sensitive surface; A protrusion or lïp 71 is posit.ioned
aro~nd the upper sur:Eace of the collector panel for shielding
the various sensors 72a, 72b, 72c and 72d which are adjacent
thereto. The protrusion or lip has sufficient width to aid
in shielding the Sun t S light rays from its adjacent sensor
when the collector is properly positioned with respect to
reflecting the Sun's light rays from reflectors 64 to focal
point 66.
The sensors 72c3 72d are interconnected to motor 1~ so
that when light strikes the sensors, t~e motor will be
activated in a rotational dîrection to turn the collector
until the light no longer strikes that sensor. The sensors
72a and 72b are positioned so that when they receive light
rays from the Sun, they cause mo~or 38 to operate and tilt
the collector until that sensor no longer receives t~e
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light rays.
Both motors operate in either rotational direction
depending upon thei.r requirement and hold their last
activated posit:ion. Tlle motors are eithcr very slow rotating,
such as a clock motor, or are
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connected to a speed step down gear box (no-t shown) to reduce
their speed to that suitable for the above requirement.
A pair of normally closed switches 77, 79 are wired
in series with sensors 72a, 72b respectively, which are in
series with moto~ 38 and hatter~ 98. The sensors have separate
series circui.ts. Switch 77 is depressed when the bottom 2~} is
rotated to i~:s maximum downward position causlng the switch to
enyacJe braclcet 83 attached -to base 12. When contac-t is made,
switch 77 opens the series circuit between sensor 72a and the
motor causing the motor to be inoperative. When the bottom 24
is ln its Figure 1 and 3 position, swi-tch 79 engages bracke-t 85
and causes motor 38 to be inoperative in the opposite direction.
This is a safety feature to prevent burn out of the motor. A
similar pair of series circuits are provided with switches
74a and 74b that engage brackets 75a and 75b respectively to
serve the same purpose as switch 77, 79 for apparatus rotating
motor 14.
It should be obvious that when conduit 70 i.s connected
~ external of the collecto.r that a flexible conduit must be
attached to its end to allow freedom of rotational and tilting
movement with the collector as required. When operating as a
closed system as hereinbefore mentioned, the conduit 70 may
be a flexible conduit.
Referring now specifically to Figures 5 and 6, the
- valves 78 are ac-tuated by the operation of their associated
push rods 80. Push rods 80 bear against cam lobe 82 secured
to drive shaft 52 for rotation therewith. Springs 81 return
the valves to a normally closed position. The valves 78 are
operable in a conventional manner to open at the required time
so as to ven-t each flash steam boiler 54 when its associated
piston reaches the end of its power stroke. The first showing
of pump 56 was a block showing of a single conventional device
well known in the diesel engine art or the like. Separate
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single pumps 56a are shown in Figures 5 and 6 as another example
of a pump system tha-t may be utilized equally as wel] to practice
khe invention. The two pumps ~6a as 56 may be supported by the
cylinder through bracket 84 as an example, however, support
means from the bottom 24 (not shown) may be utilized equally
as well to practice the invention. The pumps 56a are actuated
by means of cam 86 operating push rods 57. The pump actuators
are internally biased to bear against the cam 86 at all times.
Referrlng now specifically to Figure 1, in some
circumstances a starter system will be required to initially
turn shaft 52 so as -to provide rotation of cam 86 to actuate
the pumps 56a. The starter system includes a starter motor 88
having its rotor coaxial and attached with drive shat 52.
~ctuation of the starter motor will turn shaft 52 at sufficient
speed to properl~ actuate the pumps 56a.
The circuit for the starter motor includes a temper-
ature sensitive switch 90 positioned preferably adjacent one
of the flash steam boilers and a second switch comprising an
electrical conductive slip ring 94 positioned above a centri-
fugal ~ly weight g6 which is attached to the drive shaft 52.When drive shaft 52 turns the fly weight 96 at sufficient
speed/ it is caused to move away frorn slip ring 9~ which in
turn opens the starter motor circuit. Switch 90 and slip
ring switch 94 are wired in series with the starter 88 and
the battery 98 so that both are required to close to enable
the starter motor to operate. Therefore, the starter motor
will run only when the engine operation does not rotate shaft
52 at a speed that opens slip ring switch 94 and the tempera-
ture is su~icient to close switch 90. If either do not occur,
in the absence of the Sun, the starter motor will remain
inoperative. The power to operate the starter motor is
supplied, for example, by battery 98. It shoulcl be under~
stood that in some instances, it will be advan~ageous to
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combine the starter motor and generator into a single devicein a known manner.
It should be understood that although two steam
engine piston and cylinder combinations are shown and discussed,
that a single piston and cylinder steam engine or more than -two
piston atld cylincler combinations may be connectecl to the same
drLve shaft 52 dependincJ on power requlrem~nts ancl space
available. Each steam engine would re~uire a separate concen-
trator.
Operation of the Preferred Embodiment
The apparatus, as described, is positioned with its
side 30 having motor 38 in a generally southerly direction and
ends 32 in an east/west direction.
With the apparatus properly positioned with respect
to the Sun, the rays will be reflected by each of the mirror
segments 64 to their appropriate focal point 66 on the bottom
surface of the flash steam boiler 54.
Assume that at a given time the Sun has no-t been
visible for a period of time, and now reappears, the tempera-
ture of the collector is reduced below a pre-determined level
and the Sun's rays will not be directed to focal point 66
because of relative movement between the Sun and Earth. The
Sun's light rays will strike sensors 72a, 72b, 72c and 72d that
are exposed to direct Sun light, activating the motors 38 and
14 to position the panel to focus on focal point 66.
In the afternoon, the sensors on the North and West
would likely be exposed and in the morning/ likely the South
and East sensors would be e~posed. The sensor or sensors
receiving the Sun's light rays will cause their associated
motor to operate sensors 72a and 72b in a rotational direc-
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tion in which that sensor is directed away from direct contactwith the Sun's rays and sensor 72c will cause counterclockwise
rokation whiIe 72d will cause clockwise rotation of motor 14.
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When the sensor is shielded from the Sun's rays, then its
associated motor will stop and maintain its last rotational
position. If a second sensor 72 has been activated, a similar
operation will occur. When both of the motors are stopped,
then the rays o~ the Sun will again be clirected from the
reflectors to the Eocal point 66 on the bottom surface of
the Elash steam boiler 5~.
When the flash steam boiler 5~ reaches a predeter-
mined temperature that is sufficient to maintain piston
displacement and drive shaEt rotation switch 90 will energize
the starter motor 88. The speed of rotation of the starter
motor is suficient to cause the pistons to translate at an
operable speed taking in consideration the load of the
generator, pumps, and valves, but not sufEicient to turn
the fly weight 96 fast enough to disengage slip ring 94. When
the normal operation of the device increases the speed of the
pistons and drive shaft, the fly weight 96 will then rise and
disengage the slip ring 94 and the starter motor circuit will
then be de-eneryized.
As relative movement between the Sun and Earth is
directed by the Sun's rays again striking the sensor or
sensors, the positioning motors will be activated to re-
position the collector so that the reflective surface will
~ maintain their same focal point on the lower surface 66 to
; provide maximum heat collection.
As is well known for servo-systems, some hunting
between the motors directional rotation may occur, but a
slightly enlarged focal surface will allow the reflectlon
to be positioned on the lower surface during normal hunting
of the positioning system.
~ The positioning o~ the collector will continue to
occur as Iong as Sun light is present. Absence of Sun light
will cause the positioning to stop. When the Sun light is
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again present, a similar sequence of events will occur bringing
the positioning apparatus into operation.
When the flash boiler tempera-ture is such that the
pistons wi].l cease to operate, the switch 90 circuit is open
preven-ting operation of the starter ci.rcuit as wi-th -the
positioninc3 apparatus, returll o:E Sun light will provlde a
proper sequenee o:E events bringincJ the encjine into operation.
The invention may be embodied :in other specifie
forms without departing from the spirit or essential charaeter-
istics thereof. The present embodiment is, therefore, to beeonsidered in all aspeets as illustrative and not restrieting,
the seope of the invention being indieated by the appended
claims rather than by the foregoing description, and all
ehanges whieh eome within the meaniny and range of equivaleney
of the elaims are therefore int.ended to be embraeed -therein.
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