Note: Descriptions are shown in the official language in which they were submitted.
72184
The present invention relates to an electronic
apparatus and method for detecting the quantity of a predetermined
substance disposed in a fluid medium. In a preferred embodiment,
the present invention relates to an electronic device for
measuring the number of pounds of silver in a solution, such as
the type of solution used for medical X rays.
Heretofore, some indication of substances, such as
metals, in solution might be obtained by use of certain litmus-
type papers which are immersed in the solution, and change
appearance or color based on the substance to be detected. Such
paper detectors are inaccurate, depend upon human comparison with
color standards, and fail to give any accurate quantitative
information about the substances in solution to be measured or
detected.
The present invention provides an accurate and
electronic means for detecting and/or measuring the quantity of
the predetermined substance in a fluid medium.
Various prior electronic devices for testing, and
measuring various dielectric materials and other substances are
disclosed in Burnette, Jr., U.S. Patent 2,993,168, Batteau U.S.
Patent 3,002,150j Hopkins et al U.S. Patent 3,182,255, Liu U.S.
Patent 3,255,412, Eckfeldt U.S. Patent 2,832,734, Walrus et al
U.S. Patent 3,488,586, U.S. Pate~t 3,616,412 and British Patent
Nos. 477,849; 901,955; 1,037,627; 1,141,340; 1,167,689 and
1,203,049. However, none of these prior art disclosures and
devices disclose and/or anticipate the feature of the present
invention-which are described in greater detail hereinbelow.
The present invention provides an elèctronic apparatus
for su~stantially instantaneously detecting the quantity of a
predetermined substance disposed in a fluid medium, comprising,
in combination: first means for contacting said fluid medium
and for sensing an electrical condition of said fluid medium
-2- ~
~07Z184
caused at least in part by said predetermined substance to be
detected, said first means including a proble for sensing a
change in the resistance of said fluid medium; second means
operatively and electrically connected to said first means for
generating substantially instantaneously at least one signal
which is substantially proportional to said quantity of said
predetermined substance disposed in said fluid medium, said
second means including a light emitting diode connected in series
with said probe; third means operatively and electrically
connected to said second means for utilizing substantially
instantaneously said signal which is substantially proportional
to said quantity of said predetermined substance disposed in
said fluid medium, said third means including a meter calibrated
to read substantially instantaneously the amount of the pre-
determined substance to be detected; and said probe, by sensing
a change in the resistance of said fluid medium, acts as a
variable resistance in series with said light emitting diode,
thereby varying its light output which in turn substantially
instantaneously controls the indication on said meter, said
indication being proportional to the amount of the predetermined
substance disposed in said fluid-medium.
Brief Description of the Drawing
Figure 1 illustrates a circuit diagram according to a
first embodiment of the present invention;
Figure 2 depicts a circuit diagram according to a
second embodiment of the present invention;
Figure 3 shows a circuit diagram according to a third
~; -3-
107Z184
embodiment of the present invention.
Figure 4 illustrates a circuit diagram according to a
fourth embodiment of the present invention.
Figure 5 illustrates a combination power supply unit
and control unit for governing a silYer recovery unit which may
be used in conjunction with any of the aforementioned
embodiments of the present invention which are illustrated in
Figures 1 thru 4.
Detailed Description of Some Preferred Embodiments of
t_e Present Invention
With reference to Figure 1, there is illustrated a
first embodiment of the present invention having first means,
such as probe 1, for contacting a fluid medium, such as a
solution in which a predetermined substance such as silver is
disposed. The probe 1 is capable of sensing the change in
solution resistance.
One electrode of the probe 1 is connected to a cathode
of a light-emitting diode LED 1, whose anode in turn is
connected to one terminal of a current limiter resistor Rl. The
other terminal of the current limiting resistor Rl is connected
to the positive terminal 2 of an electrical source (not shown).
The electrical source may, for example, be approximately 1.5
volts. The other terminal, terminal 3, of the electrical
source is connected to the other electrode of the probe 1.
A series-connected variable resistor R2 and a light
detecting resistor LDR 1 are connected across terminals 2 and
3. Also connected across terminals 2 and 3 is a resistor R3
connected in series with a transistor Ql. The base of
transistor Ql is connected to terminal 4 between variable
resistor R2 and light detecting resistor LDR 1.
A series connected transistor Q2 and variable
resiStor R4 is also connected between terminals 2 and 3 of the
:
' ' ~ ~ - . .
~07Z184
electrical source. The base of the transistor Q2 is connected
to the terminal 5 between the resistor R3 and the collector
electrode o~ the transistor Ql. ~-
Also connected across the terminals 2 and 3 of the
electrical source is a potentiometer R5. A meter Ml is connected
to potentiometer R5 by means of a wiper contact, and is also
connected to a junction 6 between the variable resistance R4 and
the collector electrode of the transistor Q2.
In Figure 1, the probe 1 constitu'es the first means
for contactingthe aforesaid fluidmediumand forsensingthe electrical
condition of the fluid medium caused at least in part by the
predetermined substance to be detected.
All of the remaining components illustrated in Figure
1, with the exception of meter Ml and potentiometer R5, constitute
the aforementioned second means which is operatively and electri-
cally connected to the first means for generating at least one
signal which is substantially proportional to the quantity of the
predetermined substance, such as silver, disposed in the fluid
medium.
The meter Ml and the potentiometer R5 constitute third
means which are operativeiy and electrically connected to the
second means for utilizing the signal which is substantially
proportional to the quantity of the predetermined substance
disposed in the fluid medium.
In the embodiment illustrated in Figure 1, the resistor
Rl serves as a current limiter for the light emitting diode LED
-- - 1 and sets its operating point. The probe 1, by sensing a
change in the solution resistance, and acting as a variable
resistance in series with the light emitting diode LED 1, limits
the current flowing through the light emitting diode LED 1, and
consequently varies the light output of the light emitting diode
LED 1. This changing light level is detected or sensed by the
--5--
1072184
light detecting resistor LDR 1, which in turn varies the bias
placed on the base electrode of the transistor Ql.
The variable resistor R2 sets the operating bias of
the transistor Ql. As the conduction of the transistor Q1 varies,
the bias supplied to the base electrode of transistor Q2 also
varies. The transistor Q2 is biased to operate as an amplifier.
The varying conduction of transistor Q2 is indicated
on the meter Ml, and the indication on the meter Ml is proportion-
al to the amount of silver in the solution being tested. The
meter Ml is calibrated to read, for example, in ounces of
silver per gallon of solution. The potentiometer R5 functions
as a meter zero adjusting element. In a particular working
embodiment of the invention, the meter M1 was calibrated to
read from 0-2 indicating the ounces of silver per gallon of
solution being tested. In such a working embodiment, a meter
reading of "1" indicates one ounce of silver per gallon.
~ ith reference to Figure 2, there is shown a second
embodiment of the present invention wherein the probe electrodes
are formed from dissimilar materials. Probe electrode 7 is
connected to the base of transistor Q3, and the other probe
electrode 8, formed of a substance different than the substance
of probe 7, is connected to the negative terminal 10 of an
electrical source (not shown). A resistor R6 is connected
between the collector electrode of transistor Q3 and the other
terminal 9 of the electrical source.
A variable resistor R7 is connected between terminal
10 of the electrical source and terminal 11 at the base of the
transistor Q3. The parallel combination of a resistor R8 and a
capacitor Cl is connected between the terminal 10 and the
emitter electrode of the transistor Q3.
A series connected transistor Q4 and a variable
resistor R9 is also connected between the terminals 9 and 10 of
,. .
.
1~7Z184
the electrical source. The base of the transistor Q4 is connect-
ed to a terminal 12 intermediate to resistor R6 and the collector
electrode of the transistor Q3.
A combination meter M2 and a zero adjust potentiometer
R10, similar to the combination of meter Ml and zero adjust
R5 of the Figure 1 embodiment, is also connected between terminals
9 and 10 of the eiectrical source.
The circuit of the embodiment illustrated in Figure 2
functions essentially similar to a voltmeter. The dissimilar
materials used in the probe electrodes 7 and 8, when immersed
in a solution or electrolyte, generate a vol,age. For example,
the probe electrode 7 may be made from carbon, and the probe
electrode 8 may be made from steel. Various other combinations
of probe electrode dissimilar materials are also within the
scope of the present invention.
The resistors R6, R7 and R8 set the operating point
of the transistor Q3 which serves to amplify the voltage generat-
ed between the probe electrodes 7 and 8, This amplified voltage
is coupled to the transistor Q4, which further ampiifies it and
this amplified signal is in turn indicated on the meter M2. In
essence, the more metal that is in the solution being tested,
the greater the current flow across the probe electrodes 7 and 8
due to a decrease in the solution resistance. Any variation is
read directly by the meter M2.
~igure-3 illustrates a third embodiment of the present
invention. In Figure 3, the positive terminal 13 of an electri- -
cal source (not shown) is connected to a resistor Rll, which in
turn is connected to one terminal of a capacitor C2. The other
terminal of the capacitor C2 is connected to the emitter electrode
of a transistor Q5. The collector electrode of the transistor
Q5 is connected to terminal 13.
A resistor R13 is connected between the other terminal
107Z~84
of the electrical source and a terminal 15 intermediate resistor
Rll and capacitor 2. A resistor R12 is connected between the
base electrode of transistor Q5 and terminal 15 intermediate
resistor Rll and capacitor C2.
Series connected capacitors C3 and C4 are connected
between the terminal 14 and the base electrode of the transistor
Q5. A resistor R14 has one of its terminals connected to
terminal 16 intermediate capacitors C3 and C4, and has its other
terminal connected to electrode 17 of a probe 23. The other
electrode 18 of the probe 23 is connected to the anode of a
diode Dl whose cathode is connected to terminal 19 of the base
electrode of a transistor Q6.
A meter M3 is connected between terminal 13 and the
collector electrode of transistor Q6. A meter zero adjust
potentiometer R16 is connected across terminals 13 and 14, and
the wiper contact of potentiometer R16 is connected to the
emitter electrode of transistor Q6.
A variable resistor R15 is connec.ed in parallel with
a capacitor C8 between terminals 14 and 19. This parallel
` combination of resistor R15 and capacitor C8 functions as a
filter and bias network for the transistor Q6.
In the embodiment of the invention illustrated in
Figure 3, the transistor Q5 and the resistors Rll, R12, R13 and
R14 together with the capacitors C2, C3 and C4 constitutes a
phase-shift oscillator. The output signal from this phase-
shift oscillator section is fed to the diode Dl through the
probe 23 which is immersed in the solution being tested. The
varying resistance of the solution acts as a series-limiting
resistance which varies the amplitude of the electrical signal
reaching the diode Dl.
The signal applied to the diode Dl is rectified by the
diode Dl, and is then filtered by the resistor R15-capacitor C8
. ~ . . .
. . .
107Z184
combination which also acts as a bias network for the transistor
Q6. This varying signal controls the conduction of the
transistor Q6 which, in turn, drives the meter M3. The invention
also contemplates variations where such signal controls the
conduction of the transistor Q6, which, instead of driving a
meter M3, may drive a relay or any indicating, control or
utilization device to control, for example, a silver recovery
apparatus.
With reference to Figure 4, there is shown a fourth
embodiment of the present invention wherein a resistor R17, a
light emitting diode LED 2 and a probe 25 are connected in series
across the terminals 20 and 21 of an electrical source. Probe
electrode 22 is connected to the cathode of the light emitting
diode LED 2, and probe electrode 24 is connected to the negative
terminal 21 of the electrical source.
A capacitor C5 connected in series with light detecting
resistor LDR 2 is connected across terminals 20 and 21. Also
connected across the terminals 20 and 21 is a resistor R18
connected to one electrode of a unijunction transistor Q9, and
a resistor Rl9 connected to another electrode of unijunction
transistor Q9. The third electrode of the unijunction transistor
Q9 is connected to terminal 26 intermediate capacitor C5 and
light detecting resistor LDR 2. Series connected resistors
R20 and R21 are also connected between terminals 20 and 21.
Terminal 27 intermediate resistors R20 and R21 is connected to
the junction between resistor Rl9 and unijunction transistor
Q9.
Terminal 27 is connected to the base of a transistor
Q7. A resistor R23 is connected between terminal 20 and the
collector electrode of transistor Q7. A resistor R22 is connect-
ed between terminal 21 and the emitter electrode of transistor
Q7.
_g_
` 10~2184
.
A resistor R24 is connected between the emitter
electrode of transistor Q7 and the base electrode of a transistor
Q8. A meter M4 is connected between the terminal 20 and the
collector electrode of transistor Q8. A capacitor C6 is connected
between terminal 21 and the base electrode of transistor Q8.
A meter zero adjust potentiometer 25 is connected
between terminals 20 and 21. The wiper terminal 28 of the zero
adjust potentiometer R25 is connected to the emitter electrode
of transistor Q8.
In the circuit shown in Figure 4, the resistor R17
serves as a current limiter for the light emitting diode LED 2
and serves also to set the operating point of the light emitting
diode LED2. The probe 25, by sensing a change in solution
resistance, and acting as a variable resistance in series with
the light emitting diode LED 2, limits the current flowing :
through the light emitting diode LED 2. Consequently, this
limits and varies the light output of the light emitting diode --
LED 2.
This change in light output is sensed by the light
detecting resistor LDR 2 which, in conjunction with the : -
capacitor C5, varies the frequency of the unijunction transistor
Q9. This frequency change is fed to the.transistor Q7 where it
is amplified, filtered by the resistor R22 - capacitor C6 com-
bination, and then used to drive the transistor Q8. The meter :-
M4 thereby indicates the change in frequency caused by the
varying resistance of the solution under test.
Figure 5 shows a combination power supply unit and
a control unit for governing equipment for recovering the pre-
determined substance disposed in the fluid medium~ ~nd the Figure
5 embodiment may be used in conjunction with any of the afore-
mentioned embodiments. For example, if the Figure 5 circuitry
were to be used in conjunction with the Figure 1 embodiment,
--10--
107;~184
then the Figure 5 circuitry would replace the electrical source
of Figure 1, and components Ml, R5 and R4. In other words,
terminal 36 in Figure 5 would be connected to terminal 6 of
Figure 1, terminal 29 or 31 (actually the same electrical
terminal) of Figure 5 would take the place of the negative
terminal 3 of Figure 1, and terminal 30 of Figure 5 would take
the place of positive terminal 2 in Figure 1.
Figure 5 shows a transformer Tl connected to a full-
wave rectifier composed of diodes D2, D3, D4 and D5. Terminal
30 represents the positive terminal of the full-wave rectifier,
and terminal 29 (or 31) represents the negative terminal of the
full-wave rectifier.
~ parallel combination of a capacitor C7 and a relay
coil 32 is connected between negative terminal 31 and a
terminal 36. The relay coil 32 controls a switching element
34 for connecting between the terminals 33 and 35. Positive
te~mina~ 30 ~ the ~ull-wave rectifier is connected to switchin~
. element 34, and is also connected to one electrode of a silicone
controlled rectifier SCR 1. Another electrode of the silicone
controlled rectifier SCR 1 is connected to terminal 35. The :-
remaining electrode of SCR 1 may be used for connection to a
silver recovery apparatus. In other words, the circuitry shown
in Figure 5 and the mentioned silver recovery unit can be used
in place of the meter and zero adjust shown ln Figure 1 or
: comparable third means shown in the other embodiments.
.
--11--
