Abstract: A column of liquid is formed in a conduit for such liquid, of which flow-off amount gives then between two level measuring probes a constant value. This constant value is compared with the indicated value of a flow meter arranged in the conduit regarding the conformity in order to detect if the value indicated by the flow meter lies within a tolerance range or not. In the latter case, the error indication of the flow meter is too large and the liquid conduit is shut off. This controlling is made in arbitrary intervals automatically by the apparatus, whereby the interval is set by the speed with which the liquid column is completed.

Abstract: The mass flow of the individual goods fed from a respective storage tank by a conveying apparatus is measured by a flowmeter. The mass flow is controlled via a controller. As long as the actual value of the flow masses of each separate component does not correspond to their respective rated value, all mass flows are returned via a switch-over valve and a return line back to the respective storage tank. When all actual values correspond to their rated values, the switch-over valves will switch such that the individual components are guided through the feed line to the mixing apparatus. The mixture produced in this mixing apparatus is once more analyzed by further detecting devices. If the analyzed actual values again do not correspond to the rated analyzed values, an immediate switching of the switch-over valves to the return bypass operation is again initiated.