Calibration plug for invasive and non-invasive electrodeless conductivity sensors and methods of using the same calibration plug
View Patent ↗A calibration plug provides resistance simulation for calibrating toroidal conductivity sensors. This calibration plug includes a resistive element of predetermined electrical resistance coupled in series between electrical leads which may be engaged with a circuit element to form an electrical circuit. The toroidal sensor includes one or more toroidal coils defining a central bore extending therethrough, a cell factor, and a full scale conductivity value. The predetermined resistance of the resistive element is determined in accordance with the following equation: Resistance in Ohms = [ geometric ] cell factor ( of EC sensor ) × 1000 Full scale conductivity value in millisiemens / cm and the calibration plug further includes indicia identifying one or more toroidal conductivity sensors for which the plug is configured.
1. A calibration plug for providing resistance simulation for calibration of a toroidal conductivity sensor comprising:
a resistive element having a predetermined non-adjustable electrical resistance;
a loop cable having a proximal end and a distal end;
said proximal end being electrically coupled to one side of said resistive element;
said distal end being removably coupled to another side of said resistive element;
wherein said resistive element is electrically couplable in series between said proximal end and said distal end of said cable;
the toroidal sensor including one or more toroidal coils defining a central bore extending therethrough, a cell factor, and a full scale conductivity value;
said loop cable being configured for forming one or more loops extending through the bore with the proximal and distal ends electrically coupled to said resistive element to provide a predetermined calibration resistance;
the predetermined electrical resistance value of the resistive element being determined in accordance with the following equation:
R
(
in
Ohms
)
=
[
geometric
]
cell
factor
(
of
EC
sensor
)
×
1000
×
(
N
[
number
of
loops
]
)
2
Full
scale
[
or
1
-
loop
,
if
N
>
1
]
conductivity
value
in
millisiemens
/
cm
wherein N is the number of said loops;
wherein said full scale conductivity value is the conductivity value of one loop;
the calibration plug further including indicia identifying one or more toroidal conductivity sensors for which the plug is configured; and
wherein the calibration plug is a discrete unitary device.
2. A method of calibrating a toroidal conductivity sensor comprising:
a) providing the calibration plug of claim 1 ;
b) placing an analyzer, coupled to the conductivity sensor, in calibration mode;
c) forming one or more loops by passing a loop cable a predetermined number of times through the central bore of the sensor, and having the ends of said loop cable connected to said calibration plug; and
d) recording analyzer output corresponding to number of the loops as respective calibration values.
3. A calibration plug for providing resistance simulation for calibration of a toroidal conductivity sensor comprising:
a resistive element having a predetermined non-adjustable electrical resistance;
a plurality of electrical leads coupled to said resistive element;
said resistive element being electrically coupled in series between said electrical leads;
said electrical leads configured for operable engagement with a circuit element to form an electrical circuit including said resistive element;
the toroidal sensor including one or more toroidal coils defining a central bore extending therethrough, a cell factor, and a full scale conductivity value;
the resistive element having a predetermined electrical resistance value R1 determined in accordance with Equation 1:
R
1
(
in
Ohms
)
=
[
geometric
]
cell
factor
(
of
EC
sensor
)
×
1000
Full
scale
conductivity
value
in
millisiemens
/
cm
(
Equation
1
)
the calibration plug further including indicia identifying one or more toroidal conductivity sensors for which the plug is configured; and
wherein the calibration plug is a discrete unitary device.
4. The calibration plug of claim 3 , comprising the toroidal conductivity sensor.
5. The calibration plug of claim 3 , wherein said electrical leads comprise connector means for removably coupling to the circuit element.
6. The calibration plug of claim 5 , wherein said connector means comprise one or more connector portions sized and shaped for engaging complementary sized and shaped portions of the circuit element.
7. The calibration plug of claim 6 , wherein said circuit element comprises a loop cable having a proximal end coupled to a lead depending from one side of said resistive element, and a probe disposed at a distal end of said cable, said probe sized and shaped for receipt within a receptacle to form a complete electrical circuit including said resistive element.
8. The calibration plug of claim 3 , wherein said circuit element is selected from the group consisting of a loop cable and a calibration port of the toroidal sensor.
9. The calibration plug of claim 8 , comprising the loop cable configured for forming one or more loops extending through the bore with the proximal and distal ends electrically coupled to said resistive element to provide a predetermined calibration resistance, the predetermined calibration resistance R 2 determined in accordance with Equation 2:
R
2
(
in
Ohms
)
=
[
geometric
]
cell
factor
(
of
EC
sensor
)
×
1000
×
(
N
[
number
of
loops
]
)
2
1
/
R
1
(
from
Equation
1
)
in
millisiemens
/
cm
.
(
Equation
2
)
wherein N is the number of loops.
10. The calibration plug of claim 9 , further comprising indicia identifying resistance values associated with the number of loops.
11. The calibration plug of claim 9 wherein said loop cable forms one loop.
12. The calibration plug of claim 9 wherein said loop cable forms two loops.
13. The calibration plug of claim 9 wherein said loop cable forms three loops.
14. A method of calibrating a non-invasive toroidal conductivity sensor comprising:
a) providing the calibration plug of claim 3 ;
b) placing an analyzer in calibration mode;
c) disposing the calibration plug in the calibration port of the sensor, wherein the calibration port comprises the circuit element;
d) communicably connecting said sensor and analyzer to one another; and
e) recording analyzer output corresponding to the conductivity value of the calibration plug.
15. A calibration plug for providing resistance simulation for calibration of a toroidal conductivity sensor comprising:
resistive means for providing a predetermined non-adjustable electrical resistance;
electrical lead means for coupling to said resistive element;
said resistive means being electrically coupled in series between said electrical lead means;
said electrical lead means configured for operable engagement with a circuit element to form an electrical circuit including said resistive element;
the toroidal sensor including one or more toroidal coils defining a central bore extending therethrough, a cell factor, and a full scale conductivity value;
said resistive means having a predetermined electrical resistance value determined in accordance with Equation 1:
Resistance
in
Ohms
=
[
geometric
]
cell
factor
(
of
EC
sensor
)
×
1000
Full
scale
conductivity
value
in
millisiemens
/
cm
(
Equation
1
)
the calibration plug further including indicia means for identifying one or more toroidal conductivity sensors for which the plug is configured; and
wherein the calibration plug is a discrete unitary device.