Conductivity Measurement of Fluids

1 . A method comprising:

providing a product into a first end of a conduit that the product flows toward a second end of the conduit, wherein the conduit comprises an interior cavity, a first pair of probes attached at a first location and a second pair of probes at a second location, the first and second locations being separate from each other and being between the first and second ends;

monitoring the conductivity of the product flowing in the conduit at the first location using current measured between the first set of probes;

monitoring the conductivity of the product flowing in the conduit at the second location using current measured between the second set of probes;

introducing a marker material into an entry port so that the marker material flows with the product toward the second end, the marker material comprising a conductivity that is substantially different than the conductivity of the product;

detecting, at a first time, that the product conductivity determined at the first set of probes at the first location has changed due to the introduction of the marker material; and

detecting, at a second time, that the product conductivity determined at the second set of probes at the second location has changed due to the introduction of the marker material.

2 . The method of claim 1 , further comprising determining a residence time by subtracting the second time from the first time resulting in a time it takes the marker material to flow from the first location to the second location.

3 . The method of claim 1 , wherein the introduced marker material comprises an injection fluid.

4 . The method of claim 1 , wherein the introduced marker material comprises a volumetric source of thermal energy comprising one of microwave, ohmic or radio frequency heating energy.

5 . The method of claim 1 , wherein the introduced marker material comprises particulate food or biomaterial pretreated to increase its conductivity.

6 . The method of claim 1 , wherein the introduced marker material comprises a simulated particulate food or biomaterial fabricated from an insulating material to minimize its conductivity.

7 . The method of claim 1 , wherein the marker material is introduced so that the marker material mixes with the product to form a combined material.

8 . The method of claim 7 ,

wherein the detecting, at a first time, that the conductivity at the first set of probes at the first location has changed comprises detecting, at the first time, the conductivity of the combined material at the first set of probes at the first location, and

wherein the detecting, at a second time, that the conductivity at the first set of probes at the second location has changed comprises detecting, at the second time, the conductivity of the combined material at the second set of probes at the second location.

9 . The method of claim 1 , further comprising

monitoring the conductivity of the product flowing in the conduit at a third location using a third set of probes; and

detecting, at a third time, that the material conductivity at the third set of probes at the third location has changed due to the introduction of the marker material,

10 . A system comprising:

a conduit for carrying a product, the conduit comprising

a first end;

a second end;

a body defining a first pair of apertures at a first location and a second pair of apertures at a second location, wherein the first and second locations are separate locations and are in between the first and second ends;

an interior cavity configured to receive the product so that the product flows from the first end toward the second end; and

an introduction port for receiving an marker material which is configured to flow with the product when introduced,

a first set of probes disposed in the first set of apertures at the first location, wherein the first set of probes is configured to measure conductivity of the product located at the first location, wherein the first set of probes is further configured to detect, at a first time, that the conductivity at the first location has changed due to the introduction of the marker material; and

a second set of probes disposed in the second pair of apertures at the second location, wherein the second set of probes is configured to measure conductivity of material located at the second location, wherein the second set of probes is further configured to detect, at a second time, that the conductivity at the second location has changed due to the introduction of the marker material.

11 . The system of claim 10 , further comprising a computing device that is configured to:

record the first and second times; and

calculate a residence time by determining the difference between the first and second times.

12 . The system of claim 10 ,

wherein the first set of probes comprises a first probe and a second probe and the second set of probes comprises a third probe and a fourth probe,

wherein the first probe and second probe are disposed in the conduit opposite of each other at the first location so that a first tip of the first probe opposes a second tip of the second probe;

wherein the third probe and forth probe are disposed in the conduit opposite of each other so a third tip of the third probe opposes a fourth tip of the fourth probe.

13 . The system of claim 12 , wherein the first tip of the first probe receives a current outputted by the second tip of the second probe, and an amount of current received at the first tip is measured, and wherein the conductivity of the product is directly proportional to the measured current.

14 . The system of claim 10 , wherein the first set of probes comprises a first probe and a second probe; wherein the first and second probes arc opposingly disposed in the conduit so that the first probe and second probe face each other and are both disposed in a plane that is perpendicular to a longitudinal axis of the conduit.

15 . The system of claim 10 , wherein the conduit further comprises an interior wall and an insulating layer covering the interior wall so that the first set of probes is electrically insulated from the interior wall.

16 . A method comprising:

providing a conduit comprising a first set of probes and a second set of probes, wherein each of the first and second set of probes are spaced from each other along a length of the pipe, wherein the first set of probes oppose each other and are orientated radially about the pipe at a first radial position, and wherein the second set of probes oppose each other and are orientated radially about the pipe at a second radial position, wherein the first radial position is different from the second radial position;

measuring, using current measured between the first set of probes, conductivity of the material within the conduit when the material is at the first set of probes;

measuring, using the second set of probes, conductivity of the material when the material is located at the second set of probes within the conduit; and

determining homogeneity of the flowing material based on the measurement he conductivity of the material at the first and second set of probes.

17 . The method of claim 16 ,

wherein the measuring, using the first set of probes, conductivity of a flowing material within the conduit comprises applying a current to the first set of probes and measuring the current When the current flows between the first set of probes, and

wherein the measuring, using the second set of probes, conductivity of a flowing material within the conduit comprises applying a current to the second set of probes and measuring the current when the current flows between the second set of probes.

18 . The method of claim 17 , wherein the determining the homogeneity of the flowing material comprises:

determining the conductivity of the flowing material across a first cross-section based on the measurement of the first set of probes, and

determining the conductivity of the flowing material across a second cross-section based on the measurement of the second set of probes.