Test chain calibration is used for testing mechanical belt scales, and to calibrate high capacity electronic belt scales and weighfeeders that cannot be calibrated using material tests.
During the calibration, the test chain is applied to the conveyor belt and is secured at both ends so that the chain remains stationary over the weighing length. The chain rolls on the surface of the moving belt conveyor, providing dynamic scale loading of a known weight value, and thus supplying the calibration reference.
The roller test chain simulates live material loading by causing the belt's structure to deflect similar to when material is present.
A much greater test load can be applied to high capacity belt scales and weighfeeders because most weighbridge designs can only accommodate a limited number of static weights applied to the suspension. The high capacity test load is especially important on systems using mechanical weighing elements and lever systems because they calibrate the systems with test load values close to normal operating loads.
Reference : siemens