Development of a measurement system for belt rip detection

It was also necessary to design a system that would continuously monitor conveyor operating parameters and that would immediately stop the conveyor in case a rip is detected, so that the damage remains of possibly smallest length. The system for detecting catastrophic rips in the belt is based on belt alignmentsensors with the only difference being that here precise measurement of the position of two belt edges is performed continuously. In contrast to the above solution, all commercially available belt alignment sensors operate on a zero-one basis: the belt’s operation is either aligned or misaligned.

 The test rig is a short belt conveyor with a 400 mm wide belt, whose components are shown in the picture below.




A view of the test rig

The load-carrying structure of the test rig is a steel frame (1) made of welded profiles, which were subsequently bolted together. The comparatively small overall dimensions of the belt conveyor used in tests (length of approximately 10 m) are perfect for testing the system. The conveyor belt’s (2) edges will be cut in different lengths and variants for both edges to simulate all possible conditions of belt operation (misalignment, rips that cause overlapping or moving apart of the edges) and to test the system’s ability to detect such events. Appropriately modified belt alignment sensors (4) are mounted to the test conveyor’s frame with the use of metal sheets (3). Modification of belt alignment sensors will consist in replacing the rolls that have contact with the belt with sliding elements. Another modification will consist in installing an encoder inside the sensor, which will allow to obtain satisfactory information on the alignment of the belt’s edges. The actual conveyor belt requires calculating its load, which is why already at the system’s test stage an encoder (5) was introduced with an arm and a roll, which will be scaled in order to provide information on the conveyor’s load.

The test rig was built at the Institute of Mining Engineering, Wrocław University of Technology.  It was used to perform tests that prove that the measurement equipment works effectively and correctly. The test rig is equipped with a steel-cord belt type 1600, 400 mm wide and 17 m long. Inverter type SJ100 allows to regulate its speed in the range of 0 to 7.5 m/s. The conveyor allows for real-time verification of the measurement equipment and corrections of hardware/software malfunctions.