Weld Tracking System for the Boiler's Membrane Wall Overlaying

摘要

The membrane wall is one of the important parts in the boiler industry. It is a pipe-plate structure; The length of the pipe is much longer than it is outer diameter. The chemical reactions of the liquid inside the boilers lead to corrosion problem of the membrane wall. In order to protect the membrane wall from corrosion, overlaying weld should be applied. The structure of the membrane wall has low stiffness and can be easily deformed. Therefore, for automatic overlaying weld, a sensor is required to ensure the distance between the welding torch and the membrane wall. In this paper, a tracking contact sensor based on the potentiometer is introduced for membrane wall pipes. The proposed sensor is composed of three displacement detectors. The left and right ones detect the position deviation between the welding torch and the pipe in the left and right sides, respectively. The middle one detects the deviation between the torch and the pipe in the middle point. Hence, based on the negative feedback from the sensor, the torch position will be adjusted. Finally, the real-time tracking of the torch to the membrane wall is realized and the problem of welding position deviation due to the membrane wall deformation is determined.