System and process for break detection in porous elements for screening or filtering

• US 7,343,827 B2
• Filed: 11/08/2005
• Issued: 03/18/2008
• Est. Priority Date: 11/08/2005
• Status: Active Grant

• Current Assignee: M-I LLC (Schlumberger NV)
• Original Assignee: M-I LLC (Schlumberger NV)
• Inventors: Biggs, Michael A.
• Primary Examiner(s): Larkin; Daniel S.
• Assistant Examiner(s): Rogers; David A.
• Application Number:
  US11/270,050
• Publication Number:
  US 20070101802A1
• Time in Patent Office: 861 Days
• Field of Search: 738/658, 209/309, 209/310, 209/325, 209/346, 209/359, 209/360, 324/96
• US Class Current: 73/865.8
• CPC Class Codes: G01N 15/08 Investigating permeability, pore-volume, or surface area of porous materials
• CPC Class Codes: G01N 2015/084 Testing filters
• CPC Class Codes: G01N 22/02 Investigating the presence of flaws
• CPC Class Codes: G01N 9/24 by observing the transmission of wave or particle radiation through the material

Abstract

A method of detecting breaks in a porous element in a material separator is disclosed. A shielding is created in the material separator to form a barrier to RF energy. The shielding is formed with a path through the barrier capable of allowing RF energy and material to flow therethrough. The electrically conductive porous element is positioned fully across the path. An RF signal is transmitted on one side of the porous element, and signal levels of the RF signal are detected on the other side of the porous element, such that the detected RF signal crosses the porous element. A baseline signal strength indicator is established from the detected signal levels using an unbroken porous element. An operative signal strength indicator is generated from the detected signal levels. Breaks in the porous element are detected by comparing the operative signal strength indicator against the baseline signal strength indicator.

Claims

1. A method of detecting breaks in a porous element in a material separator, the method comprising:

creating shielding in the material separator forming a barrier to radio frequency (RF) energy with a path through the barrier capable of allowing RF energy and material to flow therethrough;

positioning the porous element fully across the path, wherein the porous element is electrically conductive;

providing an RF transmitter on one side of the porous element and an RF receiver on the other side of the porous element;

operating the transmitter to sweep an RF signal through a range of frequencies;

operating the receiver to detect the signal level at a plurality of discrete frequencies within the range of frequencies and using a controller to determine an operative signal strength from the received signals; and

determining that a break in the porous element is present by comparing the operative signal strength to a baseline signal strength indicator for the porous element,

wherein the baseline signal strength indicator for the porous element is determined when the porous element is unbroken by operating the transmitter to sweep an RF signal through a range of frequencies, operating the receiver to detect the signal level at a plurality of discrete frequencies within the range of frequencies wherein the detected RF signals cross the unbroken porous element, and establishing the baseline signal strength indicator from the detected signal levels.

2. The method of claim 1, wherein transmitting the RF signal includes sweeping the transmitted RF signal through the plurality of discrete frequencies.

3. The method of claim 1, wherein the electrically conductive porous element comprises a screen including metal screen cloth.

4. The method of claim 1, wherein establishing the baseline signal strength indicator includes averaging two or more detected signal levels.

5. The method of claim 4, wherein establishing the baseline signal strength indicator includes averaging the three highest detected signal levels.

6. The method of claim 1, wherein generating the operative signal strength indicator includes averaging two or more detected signal levels.

7. The method of claim 6, wherein generating the operative signal strength indicator includes averaging the three highest detected signal levels.

8. A method of detecting breaks in a porous element in a material separator, the method comprising:

creating shielding in the material separator forming a barrier to radio frequency (RF) energy with a path through the barrier capable of allowing RF energy and material to flow therethrough;

positioning the porous element fully across the path, wherein the porous element is electrically conductive;

providing an RF transmitter on one side of the porous element and an RF receiver on the other side of the porous element;

operating the transmitter to sweep an RF signal through a range of frequencies in the microwave range of electromagnetic energy;

operating the receiver to detect the signal level at a plurality of discrete frequencies within the range of frequencies and using a controller to determine an operative signal strength from the received signals; and

determining that a break in the porous element is present by comparing the operative signal strength to a baseline signal strength indicator for the porous element,

wherein the baseline signal strength indicator for the porous element is determined when the porous element is unbroken by operating the transmitter to sweep an RF signal through a range of frequencies, operating the receiver to detect the signal level at a plurality of discrete frequencies within the range of frequencies wherein the detected RF signals cross the unbroken porous element, and establishing the baseline signal strength indicator from the detected signal levels.

9. The method of claim 8, wherein the electrically conductive porous element comprises a screen including metal screen cloth.

10. The method of claim 9, wherein establishing the baseline signal strength indicator includes averaging two or more detected signal levels.

11. The method of claim 10, wherein establishing the baseline signal strength indicator includes averaging the three highest detected signal levels.

12. The method of claim 9, wherein generating the operative signal strength indicator includes averaging two or more detected signal levels.

13. The method of claim 12, wherein generating the operative signal strength indicator includes averaging the three highest detected signal levels.

14. A method of detecting breaks in a porous element in a material separator, the method comprising:

creating shielding in the material separator forming a barrier to radio frequency (RF) energy with a path through the barrier capable of allowing RF energy and material to flow therethrough;

positioning the porous element fully across the path, wherein the porous element is electrically conductive;

providing an RF transmitter on one side of the porous element and an RF receiver on the other side of the porous element;

operating the transmitter to sweep an RF signal through a series of discrete frequencies in the microwave range of electromagnetic energy;

operating the receiver to detect the signal level at each discrete frequency and using a controller to determine an operative signal strength from the received signals by averaging two or more detected signal levels; and

determining that a break in the porous element is present by comparing the operative signal strength to a baseline signal strength indicator for the porous element,

wherein the baseline signal strength indicator for the porous element is determined when the porous element is unbroken by operating the transmitter to sweep an RF signal through a series of discrete frequencies, operating the receiver to detect the signal level at each discrete frequency wherein the detected RF signals cross the unbroken porous element, and establishing the baseline signal strength indicator from the detected signal levels by averaging two or more detected signal levels.

15. The method of claim 14, wherein the electrically conductive porous element comprises a screen including metal screen cloth.