| 摘要 |
Apparatus for the staged, controlled dilution of a sample comprised of a particulate solids containing fluid with a preselected amount of a fluid diluent. The apparatus consists of a plurality of vessels connected together in series such that diluent introduced into the first vessel flows consecutively from vessel to vessel, to exit from the last vessel of the series. The raw sample of particulate solids is introduced into the last vessel of the series, diluted, and progressively diluted specimens of the original sample are transferred from vessel to vessel countercurrent to the flow of diluent. The sample, diluted with a preselected quantity of diluent in the several stages of dilution, is finally removed from the first vessel of the series, suitable for analysis, e.g., via the use of electronic counters. Preferably from about 3 to about 5 dilution stages are provided, and positive displacement pumps are used to withdraw diluted sample from a downstream stage and reintroduce the sample into an upstream stage to further progressively dilute the sample. Preferably, also, the pumps are driven by a common drive means to assure better control of flow rates.
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