Note: Descriptions are shown in the official language in which they were submitted.
' 20~97~
The present invention relates to a dual bed
cathodic protection system with automatic controls and
method of use utilizing an impressed cathodic protection
anode assembly powered through a solar power supply in
conjunction with a sacrificial cathodic protection anode
assembly which is known in the prior art to use a
corrosion element to emit the necessary electrical current
to protect a structure assembly from the effects of
corrosion.
The prior art includes U.S. Patent Nos.
3,612,898, 3,696,365, 4,136,309, 4,351,703, 4,413,679,
4,495,990, 4,561,949, 4,588,022, and 4,592,818.
U.S. Patent No. 3,612,898 discloses a cathodic
protection apparatus and method utilizing a D.C. power
source plus having a new and novel control circuit. U.S.
Patent No. 3,696,365 discloses a cathodic protection
system having a mechanical signaling device to indicate
system failure. U.S. Patent No. 4,136,309 is drawn to a
control circuit utilizing solar power with storage
batteries. U.S. Patent No. 4,351,703 discloses a cathodic
protection monitoring system which utilizes a plurality of
spaced specimens along the length of the pipe which are
monitored to maintain the proper protective cathodic
current. U.S. Patent No. 4,413,679 is drawn to a wellbore
cathodic protection system for oil well drilling in the
arctic region where permafrost being highly resistive is a
problem in obtaining such cathodic protection. U.S.
Patent No. 4,495,990 is drawn to an apparatus for passing
electrical current through an underground formation and,
more specifically, to a new and novel anode structure.
U.S. Patent No. 4,588,022 is drawn to an anodic protection
system utilized in heat exchangers for cooling sulfuric
acid.
A cathodic protection system is known in the
prior art and utilizes a D.C. energy voltage and current
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of proper polarity and intensity being applied to a
metallic surface which is then forced to serve as a
cathode on a closed electrical operation of a purposely
constructed electrolytic cell. Cathodic protection is
achieved by the application of the D.C. energy and the
nature of the source of the required D.C. energy has no
significant influence on the system's effectiveness. The
power source can be a conventional electrical source which
may be generated by oil, gas, coal, or nuclear power means
but some of these sources have become expensive to operate
and, of course, not available in certain remote locations.
A cathodic protection system mainly consists of
1) special electrodes installed in the electrolyte or
ground surface in soil or water and these are called
anodes or anode ground bed; 2) a source of D.C. energy
which may be a separate electrical device or special
anodes such as a galvanic anode which may be an impressed
cathodic protection anode or a sacrificial cathodic
protection anode; 3) the structure to be protected is
normally buried within the ground such as oil and gas
pipes, water well pipes, bridge structures, and such
structures served as a cathode of the purposely
constructed electrolytic cell; 4) a continuous electrolyte
to convey electrical voltage and current from the anode to
the cathode (structure to be protected); and 5) a metallic
circuit which provides an electrical coupling of the
proper polarity between the components of the cathodic
protection system.
The galvanic anode system is a major portion of
the cathodic protection system and a sacrificial cathodic
protection anode is one which deteriorates while it
requires no external power energy source to achieve its
driving electrical potential.
The impressed current system in a cathodic
protection system is limited in voltage and current only
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by their design ratings but an external energy source is
required and in our invention we are utilizing a power
supply to the impressed current system to provide the
cathodic protection and then switching to the sacrificial
cathodic protection system when the external power source,
i.e., solar power, is not available.
The present invention provides a cathodic
protection system for a metallic structure buried in the
earth, the system comprising an impressed anode assembly
buried in the earth in proximity with said metallic
structure; a sacrificial anode assembly buried in the
earth in proximity with said metallic structure; a solar
power source for providing an output voltage that
increases with increasing intensity of sunlight incident
thereon and that decreases with decreasing intensity of
the sunlight incident thereon; first connecting means,
powered solely by said solar power source, operative for
selectively connecting and disconnecting said sacrificial
anode assembly with said metallic structure; second
connecting means, powered solely by said solar power
source, operative for selectively connecting and
disconnecting said solar power source between said
impressed anode assembly and said metallic structure; and
sensing means, coupled to said solar power source and to
said first and second connecting means, for sensing the
output voltage of said solar power source, said sensing
means being operative, upon sensing that the output
voltage of said solar power source has fallen below a
predetermined level, for causing said first connecting
means to connect said metallic structure to said
sacrificial anode assembly and for causing said second
connecting means to disconnect said solar power source
from said metallic structure and said impressed anode
assembly, said sensing means being further operative, upon
sensing that the output voltage of said solar power source
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has risen above said predetermined level, for causing
said first connecting means to disconnect said metallic
structure from said sacrificial anode assembly and for
causing said second connecting means to connect said
solar power source to said metallic structure and said
impressed anode assemble.
The present invention also provides a cathodic
protection system for a metallic structure buried in the
earth, the system comprising a ground bed assembly buried
in the earth, said ground bed assembly comprising an
impressed anode assembly and a sacrificial anode
assembly, each operatively associated with the metallic
structure; a solar power source for providing an output
voltage that increases with increasing intensity of
sunlight incident thereon and that decreases with
decreasing intensity of the sunlight incident thereon;
and a system automatic control assembly, coupled to said
solar power source and to said ground bed assembly, said
system automatic control assembly being powered solely by
said solar power source and being generally operative for
selectively controlling said impressed anode assembly and
said sacrificial anode assembly, said system automatic
control assembly being specifically operative for
connecting the output voltage provided by said solar
power source to said impressed anode assembly during
periods of time when sunlight is incident on said solar
power source.
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The system and method of this invention is operable
in a preferred embodiment to utilize a solar power supply
with a cathodic protection system to protect a buried
structure from corrosion without requiring an external
electrical power supply. The ob]ect of the cathodic
protection system is to establish and maintain electrical
chemical condition at the metallic surface of the item to
be protected which is in contact with a continuous
electrolyte such as soil and water which counteracts the
anodic effects of the normal electrochemical corrosion
process. In the dual bed cathodic protection system with
automatic controls of this invention, it is noted that
either a deep well ground bed assembly or a shallow
surface ground bed assembly may be utilized, each having
1) an impressed cathodic protection anode assembly; and
2) a sacrificial cathodic protection anode assembly and
both connected to a system automatic control assembly.
The impressed cathodic protection anode assembly is
provided with a plurality of impressed anode members
which are buried in the ground and surrounded by a
suitable backfill material (coke breeze) and separated by
an insulation material (pea gravel) placed between the
impressed anode members and the sacrificial cathodic
protection anode assembly. The sacrificial cathodic
protection anode assembly includes a plurality of
sacrificial anode members which are surrounded by a
backfill material (bentonite); separated by the
insulation material from the impressed cathodic
protection anode assembly; and connected to the system
automatic control assembly. The system automatic control
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assembly includes a plurality of control circuit members
to indicate the status of the system which is all
interconnected by an
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electrical control circuit. The electrical control
circuit is operable to receive electrical power generated
through solar panels which are automatically controlled
when sunlight is available to activate a control relay and
present cathodic protection between the impressed cathodic
protection anode assembly and the normal buried structure
being protected. On receiving a decrease in voltage from
the solar power supply, the control relay is de-activated
to automatically transfer the protection to the buried
structure being achieved from the sacrificial cathodic
protection anode assembly. Conversely, it is noted that
on achieving sunlight and sun rays to the solar power
supply, the system automatic control assembly operates to
again switch the protection system from the sacrificial
cathodic protection anode assembly to the impressed
cathodic protection anode assembly. Another embodiment of
this invention utilizes a plurality of solar panels in the
solar panel assembly so as to provide a dual bed of
sacrificial cathodic protection anode assemblies, one of
each associated with a respective protected structure
assembly. This embodiment is operable to provide dual
structure protection with the use of a single impressed
cathodic protection anode assembly and a pair of
sacrificial cathodic protection anode assemblies. In the
case of dual structures being protected, a separate dual
structure electrical control circuit is provided in order
to achieve new, and novel automatic controls.
Various other features and advantages of the
invention will become apparent to those skilled in the art
from the following discussion, taken in conjunction with
the accompanying drawings, in which:
Figure 1 is a schematic diagram of the dual bed
cathodic protection system with automatic controls of this
invention utilizing either a deep well ground bed assembly
or a shallow surface ground bed assembly to provide
cathodic protection to a buried structure:
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Figure 2 is an electrical schematic diagram of an
electrical control circuit used to protect the dual bed
cathodic protection system with automatic controls as
illustrated in Figure l;
Figure 3 is a view similar to Figure 1
illustrating a second embodiment of a dual bed and
multiple protected structure cathodic protection system
with automatic controls utilizing either a deep well or a
shallow surface ground bed assembly to provide protection
to a plurality of buried structures;
Figure 4 is an electrical schematic diagram of an
electrical control circuit utilized with the second
embodiment as illustrated in Figure 3; and
Figure 5 is a front elevational view of a system
automatic control assembly of the dual bed cathodic
protection system with automatic controls.
On referring to the drawings in detail and, in
particular to Figure 1, a dual bed cathodic protection
system with automatic controls of this invention,
indicated generally at 12, includes 1) a solar power
supply 14; 2) a deep well ground assembly 16 or a
surface/shallow ground bed assembly 18; 3) a system
automatic control assembly or sensing means 20; and 4) a
protected structure assembly or metallic object 22. The
solar power supply 14 includes a solar panel assembly 21
mounted on a panel support assembly 24.
The solar panel assembly 21 includes a solar
panel member 26 of a generally conventional nature
operable to be directed normally in a southerly direction
to receive the maximum amount of sun rays thereon in order
to generate electrical output therefrom.
The panel support assembly 24 includes an upright
support pole 28 inserted through a ground surface 31 and
secured to a base anchor support 30.
The deep well ground bed assembly 16 is
illustrated as positioned below the ground surface 31 at a
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depth to be in a permanent moisture condition and includes
1) an impressed cathodic protection anode assembly or
means 32; and 2) a sacrificial cathodic protection anode
assembly or means 34. The impressed cathodic protection
anode assembly 32 is known in the prior art and supplied
with an impressed current or through a rectifier system
through the use of an energy source such as electricity,
wind power, fuels, or solar power. The use of a solar
powered impressed cathodic protection anode system is
known in the art but such systems are either 1) utilized
with batteries which entail a large initial investment
expense and maintenance; or 2) the solar power unit only
affords corrosion protection when sun light is available
and, therefore, no protection when sunlight is not
available which is not a desirable end result.
The impressed cathodic protection anode assembly
32 includes 1) a plurality (illustrated as four) of
adjacent but spaced impressed anode members 38; 2) an
impressed anode connector assembly 40; 3) a backfill
material 42 enclosing the impressed anode members 38; and
4) an insulation material 44 to electrically separate the
impressed cathodic protection anode assembly 32 from the
sacrificial cathodic protection anode assembly 34.
It has been found that the use of a coke breeze
material as the backfill material 42 and pea gravel as the
insulation material 44 achieves the best results.
The impressed anode connector assembly 40 is
provided with electrical connector lines 46 interconnected
to each of the impressed anode members 38 and then
connected to a main common line 48 connected to the system
automatic control assembly 20.
The sacrificial cathodic protection anode
assembly 34 is of a galvanic type or gravity flow cathodic
protection system utilizing a corrosive material that is
less noble than the systems to be protected and is
.
; 203~37~ 1
specifically known as a corrosion cell where corrosion
occurs to provide the cathodic protection. The
sacrificial cathodic protection anode assembly 34 includes
1) a plurality (illustrated as four) of spaced sacrificial
anode members 52; and 2) a sacrificial anode connector
assembly 54 which is connected to the system automatic
control assembly 20.
The sacrificial anode connector assembly 54
includes a plurality of connector line sections 56
interconnecting the anode members 52 to a main common line
section 58 which electrically connects same to the system
automatic control assembly 20. Additionally, a backfill
material 42 preferably of a bentonite material is used to
surround the sacrificial anode members 52 and the
insulation material 44 being pea gravel is used to
electrically insulate same from the impressed cathodic
protection anode assembly 32.
A wire 47 connects the system automatic control
assembly 20 to the protected structure assembly 22. As
noted in Figures 1 and 3, the deep well ground bed
assembly 16 can be replaced with a surface shallow ground
bed assembly 18 which provides the same end result and
function but is placed within 8 feet to a maximum of 20
feet in depth below the ground surface 31. The surface
shallow ground bed assembly 18 includes the previously
described impressed cathodic protection anode assembly 32
and the sacrificial cathodic protection anode assembly 34.
The system automatic control assem~ly 20 includes
1) a control cabinet member 62; 2) a plurality of
controlled circuit members 64 mounted within the control
cabinet member 62; 3) an electrical control circuit or
first and second connecting means 66 to interconnect the
elements of the control circuit member 64 to the solar
power supply 14 of the deep well ground assembly 16; and
4) a dual structure electrical control circuit or first
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and second connecting means 67 utilized similarly to the
electrical control circuit 66 except utilized with a
plurality of solar panel members and a plurality of
protected structure assemblies as will be explained.
The control cabinet member 62 includes a
generally box member 68 having a lid member 70 pivotally
connected to one upright edge thereof and held in a closed
condition by conventional latch type structures to lock
same for security purposes.
As noted in Fig. 5, the control circuit members
64 mounted within the box member 68 include 1) a volt
meter member 76; 2) an amp meter member 80; 3) a plurality
of connector terminal blocks 82; 4) amperage adjustment
member 84; 5) an interrupt switch 85; and 6) a fuse
container member 86.
The volt meter member 76 utilizes a volt meter
switch 88 to periodically check the D.C. voltage as being
applied to the system either through the impressed
cathodic protection anode assembly 32 or the sacrificial
cathodic protection anode assembly 34.
The amp meter member 80 is controlled though an
amp meter switch 90 which is also utilized to periodically
measure the amperage being obtained and utilized through
the impressed cathodic protection anode assembly 32 and
the sacrificial cathodic protection anode assembly 34.
The terminal blocks 82 include 1) a positive
block 92 which is connected from the solar power supply
14; 2) a negative block 94 connected to the negative pole
of the solar power supply 14; 3) a pipe block 96 to be
connected to the structure assembly 22 being protected; 4)
an impressed bed block 98 being connected to the impressed
cathodic protection anode assembly 32; and 5) a
sacrificial bed block 102 which is connected to the
sacrificial cathodic protection anode assembly 34. The
amperage adjustment member 84 is operable to selectively
control the amperage supply to the system as will be noted.
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The interrupt switch 85 is operable to disconnect
the solar power supply 14 from the system automatic
control assembly 20 so that the output from the
sacrificial bed, more particularly, the sacrificial
cathodic protection anode assembly 34, can be tested
during daylight hours.
The volt meter member 76 and the amp meter member
80 can be eliminated with the test points provided so that
a portable hand held meter can be used for periodic
voltage and amperage measurements.
The fuse member 86 is operable in a conventional
manner to prevent overload conditions to the electrical
control circuits 66 or 67 due to malfunction of the solar
power supply 14.
As noted in Figure 2, the electrical control
circuit 66 includes solar panel power inlet terminals 104
of a negative input and 105 of a positive input which is
indicated in lines 106, 108 respectively. A line 112
between lines 106, 108 and between terminals 109, 111 has
a zener diode 110 (Z1) connected therein. The zener diode
110 is placed across the output of the solar panels
between terminals 109, 111 to control the output voltage.
The zenier diode 110 operates to achieve a constant
voltage of a predetermined or consistent output of the
system.
A line 114 is connected between power inlet lines
106, 108 and each respectively connected in a test point
terminal 116, 118. The test point terminals 116, 118 are
connected to the volt meter member 76 and volt meter
switch 88 so as to periodically, as desired, read the
output voltage in power inlet lines 106, 108 to assure
that the system is within desirable operating limits in
regard to voltage.
A line 122 is interconnected between the power
inlet lines 106, 108 having a relay member or coupling
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means 124 (RYl) and a resistor 126 (Rl) connected
therebetween in series. The relay 124 is of a 12-volt
double pole, double throw type but the relay voltage can
vary depending on a particular application.
The resistor or adjustable resistance means 126
(Rl) is utilized as, when the sun rises and the voltage
increases from the solar power supply 14, the voltage
drops across the resistor 126 (Rl). This voltage drop
allows a higher than normal voltage to be reached by the
solar power supply 14 before the relay 124 (RYl) is
energized.
A line 128 is connected on opposite sides of the
relay 124 (RYl) and having a capacitor 132 (Cl) mounted
therein. The capacitor 132 stores electrical energy and
allows the overall system to operate smoothly on
energizing and de-energizing the relay 124 (RYl) without
chatter of the contact points therein.
Lines 134, 136 are respectfully connected to the
power iniet lines 106, 108 and being interconnected
through normally opened relay contact points (RY1)
indicated at 138, 140 respectively.
A line 142 is connected on the output side of the
relay contact 138 and extended through a normally closed
relay contact 144 of the relay 124 (RYl). It is then
connected through a line 146 to the sacrificial cathodic
protection anode assembly 34.
A line 150 is connected to the junction of line
142 and 134 which is a continuation of the power line
106. The line 150 is connected through a resistor 152
(R3) and line 154 to the protected structure assembly 22.
The resistor 152 (R3) is a calibrated shunt resistor which
allows current measurement without breaking the circuit
and interrupting protection to the protected structure
assembly 22.
A line 156 is interconnected between lines 122
and 142 and having a resistor 158 (R2) mounted therein.
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The resistor 158 (R2) allows a small amount of current to
pass around the normally open contacts 138, 140 when the
conditior of the rising sun puts a voltage on the solar
power supply 14. The resistor 158 (R2) then slowly loads
the impressed cathodic protection anode assembly 32 before
the relay 124 (RY1) is energized. This combination of
resistors or first adjustable resistance means 126 (Rl)
and 158 (R2) work together to aid the entire system in
working in a smoother manner and prevents shattering of
the contacts of the relay 124 (RY1). It is found through
research and development that, if the resistors 126 (R1)
and 158 (R2) are not used, the entire system may energize
and then kick off because of voltage drop caused by
loading the system all at once. By dropping the voltage
across the resistor 126 (R1), this allows the solar power
supply 1~ to have an extra power boost to keep the relay
124 (RYl) energized.
A line 160 is interconnected between lines 122,
136 and by-passes the resistor 126 (Rl) and the normally
open relay contact 140 (RYl). The line 160 allows the
resistor 126 (Rl) to be by-passed when the relay 124 (RY1)
is energized to allow the full solar power supply 14 to be
placed across the relay 124 (RYl) to prevent the
chattering of the electrical contacts therein due to low
voltage being applied to the coil of the relay 124 (RYl).
A line 162 is connected to a juncture of the
output of relay contact 140 (RYl) and line 160 and is
trained in series through a resistor 164 (R4), and a diode
or diode means 166 (Dl) and connected to the impressed
cathodic protection anode assembly 32 which, collectively,
is known as a circuit by-pass means. The resistor 164
(R4) is of an adjustable type and used to regulate the
voltage and current output of the impressed cathodic
protection anode assembly 32 which is powered through the
solar power supply 14. This allows the operator of the
21~3~7~
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entire dual bed cathodic protection system with automatic
controls 12 of this invention to meet the specific needs
of the protected structure assembly 22 in light of the
prevalent soil conditions.
The diode 166 (D1) is of a type used on a low
energized system and is of a type used on a low energized
system and is operable to prevent the relay 124 (RY1) from
being re--energized by the voltage difference of the
sacrificial and impressed ground beds after the solar
panel voltage is low enough to de-energize the system.
There may be a voltage difference between the impressed
and sacrificial ground cathodic protection anode
assemblies 32, 34 being sufficient enough to keep the
relay 124 (RY1) energized. The diode 166 (D1) allows the
relay 124 (RY1) to de-energize by blocking the flow of
current from the sacrificial cathodic protection anode
assembly 24 to the impressed cathodic protection anode
assembly 32.
In another embodiment of this invention, as
generally indicated in Figs. 3 and 4, a dual bed multiple
protected structure cathode protection system with
automatic controls 170 of this invention is utilized with
the dual structure electrical control circuit 67. The
dual structure electrical control circuit 67 is similar to
the electrical control 66 except utilizing 1) a pair of
structures to be protected; and 2) a pair of sacrificial
cathodic protection anode assemblies as will be explained.
As noted in Figure 4 as to the electrical
schematic of this second embodiment, we utilize the solar
panel power inlet terminals 104, 105 which are connected
respectively to the power inlet lines 106, 108 and, in
turn, to the terminals 109, 111. The elements leading
from the inlet terminals 104, 105 are identical to those
described in electrical control circuit 66 except line 154
leads to a second protected structure as will be
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described. The previously described elements featured are
used being the zener diode 110 (Z1); test point terminals
116, 118; relay 124 (RYl); resistor 126 (R1); capacitor
132 (C1); normally closed contacts 144 (RY1); shunt
resistor 152 (R3); resistor 158 (R2); resistor 164 (R4):
and diode 166 (D1) which are respectfully interconnected
to the impressed cathodic protection anode assembly 32 and
the sacrificial cathodic protection anode assembly 34.
The new electrical components of the dual
structure electrical control circuit 67 are illustrated on
the left side of Figure 4 and includes an inlet power
terminal 175 connected to a second one of the solar panels
being utilized as will be described. This panel power
inlet line 176 is of a negative nature as noted by
terminal 177.
A line 178 is connected to the power inlet line
108 and through a zener diode 179 (Z2) mounted therein.
The zener diode 179 (Z2) is connected to the second solar
panel, as will be noted, to control the out~ut voltage and
achieve constant voltage of a predetermined level.
A line 180 is connected between the power inlet
line 176 and the positive power inlet line 108 and having
test points 181, 182 mounted therein. The test points
181, 182 are selectively connected to the volt meter
member 76 (or contacted by a hand held meter for voltage
measuremènts) and controlled through the volt meter switch
88 to present a voltage reading to check the voltage
system in regard to the output of the second solar panel.
The panel power inlet line 176 is then conn~cted in series
to a normally open relay contact 186 (RY1) from the relay
124 (RY1); an adjustable resistor 188 (R6); and a shunt
resistor 190 (R7) which is connected to the second
structure to be protected as will be noted.
A line 192 is connected to the power inlet line
176; by-passes the normally open relay contact 186 (RY1);
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and having a resistor 193 (R5) mounted therein; and
connected again to the power inlet line 176. This aids in
slowly loading the system before the relay 124 (RYl) is
energized just as resistor 158 does with protection of the
single structure system being the protected structure
assembly 22.
A line 194 is connected through the resistors 188
(R6) and 190 (R7) through a normally closed relay contact
196 (RY1); and connected to a second sacrificial cathodic
protection anode assembly 198. The second sacrificial
cathodic protection anode assembly 198 is identical in
structure to the previously described sacrificial cathodic
protection anode assembly 34 as one such sacrificial bed
is needed for each of the buried structures being
protected.
As noted in Figure 3, the dual bed and multiple
protected structure cathodic protection system with
automatic controls in 170 includes 1) a dual solar power
supply 202; 2) the deep well ground bed assembly 16 or the
surface shallow ground bed assembly 18; 3) the system
automatic control assembly 20; and 4) a dual protected
structure assembly 204.
The dual solar power supply 202 is similar to the
solar power supply 14 except having a solar panel assembly
206 supported on the panel support assembly 24 as
previous'.y described. The solar panel assembly 206 is
provided with a pair of solar panel members 208 which are
substantially identical in structure and operation to that
previously described for the solar panel member 26.
The system automatic control assembly 20 for the
second embodiment has been described with the dual
structure electrical control circuit 67 utilized therewith.
The dual protected structure assembly 204 is
provided with a first protected member 210 and a second
protected member 212. It is obvious that numerous types
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of structures to be protected can be utilized with the
requirement being a separate solar panel member 208 for
each structure being protected and, additionally, with a
sacrificial cathodic protection anode assembly 34 or 198
for each structure being protected. A single impressed
cathodic protection anode assembly 32 can be used to
protect numerous structures with a sacrificial cathodic
protection anode assembly 34 needed for each protected
structure.
In regard to the basic operation of the system as
noted in the electrical schematic of Figure 2, the system
utilizes two separate ground beds in conjunction with a
solar power supply to provide protection through an
impressed ground bed system during daylight or sunlight
hours and a sacrificial ground bed system during
non-sunlight hours which does not require an external
power source. The benefit of this invention is to provide
24-hour protection regardless of sunlight conditions and
allowing the impressed ground bed system to revitalize
during non-sunlight hours.
In the use and operation of the dual bed cathodic
protection system with automatic controls 12 of this
invention, it is noted in Figure 1 that the system is
operable either with the deep well ground bed assembly 16
or the surface shallow ground bed assembly 18. The choice
of the system is normally dependent on the ground
conditions as there has to be a soil condition with
moisture or other such conditions so as to provide an
electrical transmission from the impressed cathodic
protection anode assembly 32 or the sacrificial cathodic
protection anode assembly 34 to the protected structure
assembly 22. Therefore, the choice between the deep well
ground bed assembly 16 or the surface shallow ground bed
assembly 18 is dependent on the soil conditions and
determined at the time of installation.
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The solar power supply 14 is secured to the soil
beneath the ground surface 31 in a secure manner and
having the solar panel member 26 directed normally in a
southerly direction at a desired angle to receive the
maximum benefit of the sun as it is passing over the site
location. The amount of protection to be afforded to the
protected structure 22 is determined by soil conditions;
the type of protective coating placed on the protected
structure assembly 22; and the strength and availability
of solar power to the solar panel member 26. Additional
solar panel members 26 can be added to the system to
increase the solar power output. Similarly, increasing
the number of sacrificial anode members 52 will increase
the output of the sacrificial cathodic protection anode
assembly 34.
The dual bed cathodic protection system with
automatic controls 12 of this invention is basically
operable whereupon the relay 124 (RYl) is not energized
and cathodic protection is achieved with current flow from
the sacrificial cathodic protection anode assembly 34 to
the protected structure assembly 22 through the normally
closed contacts 144 (RYl) of the relay 124 (RYl).
As the sun rises, the voltage on the solar power
supply 14 increases and, when reaching a predetermined
level, the relay 124 (RYl) will energize and the normally
opened relay contacts 138, 140 will close and the normally
closed contact 144 will open thereby providing for
cathodic protection of the structure assembly 22 through
the impressed cathodic protection anode assembly 32. It
has been found that this basic system utilizing the
impressed cathodic protection anode assembly 32 and
sacrificial cathodic protection anode assembly 34, on
being controlled by the relay 124 (RYl), is operable to
provide the protection needed to the structure assembly 22.
Although the system will operate with a minimum
amount of elements, the additional improvement to the
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system in function and operation has been achieved by the
use of additions of the resistors 126 (Rl) and 158 (R2).
These resistors 126 (Rl), 158 (R2) act to allow a small
amount of current around the normally opened contacts 136,
140 of the relay 124 (RYl) when the rising sun puts its
voltage on the solar panel member 26. This slowly loads
the impressed cathodic protection anode assembly 32 before
the relay 124 (RYl) is energized. The resistors 126 (Rl)
and 158 (R2) operate together to help the system energize
smoothly and prevent a clicking or chattering of the
contact points of the relay 124 (RYl) due to perhaps a
marginal operating voltage applied to the solenoid of the
relay 124 (RYl) which would happen if the resistors 126
(Rl) and 158 (R2) were not utilized.
The zenier diodes 110 (Zl) and 179 (Z2) are
placed across the respective outputs of the solar panels
26 or 208 to control the output voltage and achieves a
constant voltage at a predetermined level for a consistent
output of the overall system. The resistors 164 (R4) and
188 (R6) are operable to regulate the output of the
impressed cathodic protection anode assembly 32 to the
protected structures 210 and 212.
The test point terminals 116, 118, 181, and 182
are operable to selectively connect to the volt meter
member 76 (or the hand held meter) to check the voltage as
achieved from the respective solar panel members 26 or 208
depending on the system being utilized.
In the method of utilizing the dual bed cathodic
protection system with automatic controls 12 of this
invention, it is noted that the system is installed as
shown in Figure 1 with the steps being 1) obtaining a
power source through the use of the sun being applied to
the solar panel member 26; 2) transferring the incoming
electrical power supply through the system automatic
control assembly 20 outwardly to the impressed cathodic
' 203~97~
-20-
protection anode assembly 32; 3) transferring an
electrical positive output pole therein to a negative pole
being the protected structure assembly 22; 4) sensing a
decrease in the amount of sun power on the solar panel
member 26 and de-energizing a relay 124 (RY1) within the
system automatic control assembly 20; 5) de-energization
of the relay 124 (RYl) operates to switch the output
generated electric power from the impressed cathodic
protection anode assembly 32 to output from the
sacrificial cathodic protection anode assembly 34 which
protects the structure assembly 22 during non-sunlight
hours; and 6) on sensing input solar energy to the solar
panel member 26, the relay 124 (RYl) is energized thus
placing the impressed cathodic protection anode assembly
32 back into the system utilizing solar power to protect
the structure assembly 22.
Further, the method of use of the dual bed and
multiple protected structure cathodic protection system
with automatic controls 170 utilized the further steps of
1) providing a pair of sacrificial cathodic protection
anode assemblies 34, 198; and 2) protecting a pair of
structures 210, 212.
The dual bed cathodic protection system with
automatic controls of this invention is operable to
utilize the impressed cathodic protection anode assembly
32 which can be powered by various means such as
electrical power, fuel, windmills, or more specifically in
our case, the use of a solar power supply which provides
economical, substantially maintenance free power being
utilized as a D.C. power supply.
The dual bed cathodic protection system with
automatic controls is operable with either a deep well
ground bed assembly or a surface shallow ground assembly
which is utilized depending on the depth of the structure
to be protected and the surrounding soil conditions.
203~7~
-21-
The dual bed cathodic protection system with
automatic controls of this invention is operable to use a
sacrificial cathodic protection anode assembly which
requires no external power and an impressed cathodic
protection anode assembly utilizing the power of the sun.
The use of solar power alone is not satisfactory as no
protection is achieved to the structure being protected
when 1) the sunlight is not available; and 2) after sunset
and before sunrise. This combination system is especially
beneficial as the use of a sacrificial cathodic protection
anode assembly is variable in output and would have to be
replaced twice as often if not utilizing the solar power
impressed cathodic protection anode assembly of this
invention.
The other systems utilizing solar power having a
battery system are very expensive in initial cost; have
substantial maintenance problems requiring skilled
personnel; and do not achieve a cost effective benefit or
function of the invention described herein.
The dual bed cathodic protection system with
automatic controls of this invention is relatively
economically in initial cost investment; reliable in
operation in automatically switching from a sacrificial
cathodic protection mode to the sun powered protection
mode; and substantially maintenance free compared to prior
art structures.
