Corrosion sensors suitable for corrosion under insulation (CUI) detection
Inventors
CASERES, Leonardo J. • DANTE, James F. • Vinogradov, Sergey A.
Assignees
Southwest Research Institute SwRI
Publication Number
US-12007322-B2
Publication Date
2024-06-11
Expiration Date
2041-10-06
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Abstract
A sensor for use in detecting corrosion under insulation (CUI) and a method for deploying the same that does not require removal of cladding and/or insulation. The sensor includes at least a first sensor element formed of a first metal and a second sensor element formed of a second metal, the first and second metals being different. One or a plurality of sleeve members formed of an electrically-insulating material, such as plastic, maintain the first and second sensor elements at a predetermined distance from each other and define at least one sensing region that extends between the first and second sensor elements. The first and second sensor elements are configured to electrically communicate based on a conductive solution being disposed in the at least one sensing region and causing a galvanic current to be induced therebetween.
Core Innovation
The invention relates to a sensor system for detecting corrosion under insulation (CUI) and also provides a non-destructive method for deploying such sensors without removing insulation or cladding from pipes or vessels. The sensor consists of at least a first sensor element made of a first metal and a second sensor element made of a second, different metal. These sensor elements are held at a specific, predetermined distance from each other by one or more sleeves made from an electrically-insulating material, such as high-density polyethylene (HDPE), which also defines sensing regions between the elements.
Detection is achieved by monitoring the electrical communication between the two sensor elements, which occurs when a conductive solution such as moisture is present in the sensing region, thereby inducing a galvanic current. The system may further utilize a hall effect sensor at a terminal located outside the insulation to measure the magnetic field generated by the galvanic current, enabling detection of corrosion-promoting conditions beneath insulation. Additionally, sensor pairs can be configured with coatings that mirror actual pipe coatings, allowing the system to detect not only the presence of moisture but also the onset and degradation of protective coating layers.
Deployment is accomplished non-destructively through a sensor dispenser that inserts the sensor through the insulation to place it adjacent to the pipe or vessel wall. The electrical interconnects enable coupling of the sensor to a terminal outside the insulation for monitoring. This solution addresses the need for scalable, low-cost, and less disruptive CUI monitoring by allowing sensor installation and operation without system shutdown or insulation removal.
Claims Coverage
There are two independent claims, each defining distinct inventive features related to CUI sensor systems and deployment methods.
Sensor system with bimetallic sensor elements and sensing region
The invention provides a sensor system for determining corrosion of a pipe or vessel, featuring: - A sensor device with first and second sensor elements formed from different metals. - Use of one or more sleeve members made of electrically-insulating material to maintain a predetermined distance and create at least one sensing region between the elements. - Configuration such that the first and second sensor elements electrically couple in the presence of a conductive solution in the sensing region, inducing a galvanic current. - A sensor dispenser designed with a bore larger than the sensor device to house and deliver the sensor through insulation, enabling placement of the sensor between the pipe/vessel coating and the insulation.
Sensor system with sensor pairs for coating degradation and moisture detection
The invention provides a sensor system comprising: - A first sensor pair formed of different metals to detect conductive solutions and induce a galvanic current. - A second sensor pair formed of different metals, where one sensor element is coated with a material matching the pipe/vessel coating and configured so that electrical communication between the elements only occurs if the coating degrades. - Sleeve members maintain specified distances between sensor elements and provide separate sensing regions for both sensor pairs. - A sensor dispenser for non-destructive placement of the sensor system between the coating and insulation.
The independent claims cover sensor systems designed for the non-destructive detection of corrosion under insulation using bimetallic sensor elements, sensing regions, sleeve-based spacing, and dispensers for deployment. The systems are capable of detecting both moisture ingress and the degradation of coating layers.
Stated Advantages
Enables corrosion under insulation detection without removal of cladding or insulation.
Provides a non-destructive, low-cost, and scalable approach to monitoring conditions giving rise to corrosion under insulation.
Allows for sensor deployment while avoiding laborious, time-consuming insulation-removal processes and potential insulation damage.
Reduces costs and complexity associated with CUI monitoring, minimizing equipment downtimes.
Documented Applications
Detection of corrosion and moisture under pipe or vessel insulation in process industries.
Detection of degradation or failure of protective coatings applied to pipes or vessels beneath insulation.
Applications where visual assessment of a component is obscured and a target measurement (such as wetness or coating degradation) cannot be captured without partial disassembly.
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