| 摘要 |
<p>It is known to use a streaming current detector (SCD) in a system for monitoring the charge condition of a sample fluid and for controlling the addition of a flocculating/coagulating agent to the fluid. It is further known to arrange the SCD to monitor a sample taken from the fluid supply, and to connect the SCD in a feedback loop to directly control the dosing of the flocculating agent into the fluid supply. Difficulties arise in complex systems, and improper control over flocculant dosing results from the effect of dosing adjustment being overshadowed by other charge-varying influences. The invention proposes a solution in which a secondary feedback loop involving dosing of a chemical (which may be the same as that added to the main supply) into the sample supply is provided aroung the SCD itself. In this way, the corrective effect of the secondary dosing is not overwhelmed by the other influences.</p> |
