This type of strainer is usually installed upstream of most of the devices in the system including the meters, backflow preventers (or detector check valves) and flow alarms, in order to protect these devices from damage caused by large particles.

• 这种类型的过滤器通常安装在系统内大多数设施的上游，包括仪表，防回流阀（或检测止回阀）和水流警报装置等，从而保护这些设施不会被大颗粒损坏。