Automated inspection of heat exchangers by ATEsystem

Partner:

ATEsystem s.r.o.

Problem:

The application is focused on the inspection of the quality of heat exchangers. Poor quality of heat exchangers results in helium leakage from the brazed joints of the exchangers. Before the implementation of the automation solution, this inspection had to be performed manually by workers. Prior manual inspection was expensive from the human resources point of view as well as due to human errors. Automated inspection is cheaper, more accurate, and more reliable.

Solution:

PhoXi 3D Scanner S

The application provides a precise, automated robotic inspection of the quality of heat exchangers. A helium leakage, the main and dangerous defect of exchangers, can be detected using a special sniffing probe that is put item-by-item to the immediate proximity of all brazed joints of the exchangers. 

The inspected exchangers are in variable positions and shapes. Therefore, the exchangers and their joints need to be precisely located in 3D space to make the automated robotic inspection possible. The localization must be very accurate because the sniffing probe often goes through a tight quarter of a one-meter-long tunnel of joints. 

The PhoXi 3D Scanner mounted onto the robotic arm is used for 3D scanning of exchangers in space. The exchangers and their joints are precisely located in space by analyzing the captured 3D data. The accurate position, orientation, and trajectory of the sniffing probe are calculated. Individual discrete 3D data analysis algorithms have been developed (instead of using conventional 3D model fitting) in order to achieve the necessary accuracy on the shiny and shape-variable surfaces of the exchangers with many optical artifacts. A specific robot–scanner calibration procedure has been developed as well.

Discussion:

ATESystem decided to use the PhoXi 3D Scanner model S based on its high-precision 3D imaging, including surface normals, high resolution, suitable scanning volume, fast scanning time, flexibility, compactness, suppression of ambient light, and Laser class 3R.

The technology enables precise 3D imaging of the whole scanned volume in one step, without the need for a relative movement of the scanner and the observed object.

The automation solution offers many advantages, including cost reduction, less personnel, elimination of human error, increased accuracy and reliability, increase productivity, and time savings.