Patent ID: 9016110
Filing Date: 2015-04-28
Classification: G01N

Abstract:
1. A method of accurately detecting the presence and concentration of an oxidant in a turbid water sample of a process water stream, the method comprising the steps of: passing the water sample through a filter array, the filter array comprises at least one filter which is a filter-band type filter comprising a first rotating wheel and a second rotating wheel around both of which a water permeable tape is wound, the wheels are constructed and arranged to rotate in the same direction and thereby the tape is unwound from the first wheel and further wound around the second wheel and the tape is washed to remove turbidity inducing material so that turbidity inducing material does not clog up the tape, the tape being washed such that before the tape is unwound from the first wheel it is essentially clean and this essentially clean tape is what the water passes through so the water only passes through an essentially clean tape, wherein the tape is permeable such that it can remove turbidity inducing material but not oxidant from the water sample, the filter is constructed and arranged to rotate and thereby prevent the accumulation and plugging of the filter by continuous contact with turbidity inducing material, then passing the filter array filtered water to an oxidant monitor that would not be able to accurately measure the oxidant concentration if the water had not been so filtered, wherein the oxidant monitor measures oxidant levels using N,N-diethyl-p phenylenediamine indicator reagent, holding, at least in part, the filter-band type filter in place by a pressure gradient caused by a pump, the pressure gradient configured for pulling the tape in a direction of water sample flow from the filter array to the oxidant monitor, and returning from the monitor a measurement of the concentration, the monitor continuously measuring the concentration of an oxidant from the process water stream.