A test chain is a dynamic test equipment for adjustment of built-in belt scales. Test chains simulate the material loading on the weighing frame of belt scales. It is used, if the adjustment with reference material isn’t possible.
The test chain consists of roll weights, which are combined with a link chain. For transport and handling, the test chain is removable in segments.
For adjustment, the test chain is placed on the belt conveyor and fixed at both ends. The roll weights are rotated on the surface of the moving belt conveyor. The known chain weight thus shows a defined and dynamic band loading of the scale.
The size of the test chain is selected according to the conveyor capacity so that a relevant belt loading is simulated. This should be at least 20% of the normal material load.
Firstly, a zero balance of the scale is operated. In the next step, the test chain is placed in its segments amounting to the weighing platform of belt scale and then it is mounted. The chain is fixed with both ends on the side wall of belt conveyor, so that it runs in the center of belt conveyor as well as on at least one idler on the left and right of the scale.
Then starts the first testing with at least five tape runs respectively three minutes with nominal belt speed. The roll weights of test chain rotate on the surface of moving conveyor. The known weight chain represents a belt loading of the belt scale. The calculation results from the integration of the measuring values (kg/m x belt speed v x time) on basis of reading of the meter. If required, the adjustment factor are corrected by means of the recorded test data. For checking, at least another test run starts – until the calculated flow rate accords with the simulated flow rate through the test chain.
