同时计算单个颗粒的数量和大小的仪器可用于分析原水颗粒、优化化学剂量、测量过滤废水中的颗粒、根据颗粒去除率确定过滤效率，以及许多其他应用。然而，单粒子计数器不会普遍适用于所有这些情况。所需颗粒计数器的类型将由待分析水样的类型和数据的最终用途决定。 商用颗粒计数器在工作原理、复杂性、颗粒大小范围能力、浓度限制、分辨率、数据处理能力和物理安装要求方面有所不同。本文讨论了颗粒计数器的基本特征和一种逐步评估颗粒计数器性能的方法，以及在离散和在线采样配置中进行水质监测的安装注意事项。包括15个参考文献、表格和图表。

Instruments that simultaneously count and size individual particles can be used for analyzing raw-water particulates, optimizing chemical dosages, measuring particulates in filter effluent, determining filter efficiency in terms of percent removal of particles, and many other applications. A single particle counter will not, however, be universally applicable to all of these circumstances. The type of particle counter required will be determined by the types of water samples to be analyzed and the ultimate use of the data. Commercially available particle counters differ in terms of operational principles as well as complexity, particle size range capabilities, concentration limits, resolution, data-processing power, and physical installation requirements. Basic features of particle counters and a step-by-step approach for evaluating particle counter capabilities are discussed, along with installation considerations for water quality monitoring in discrete and on-line sampling configurations. Includes 15 references, tables, figures.