您要查找的是不是：
- 第一止回阀受到污染;或 The first check valve is fouled; or
- 建议在防回流阀前安装一个过滤器，防止止回阀受到污染和阀门在再增压期间出现泄漏或溢出。 The installation of a strainer ahead of the backflow preventer is recommended to prevent fouling of the check assembly and resultant spillage from the valve during repressurizing.
- 第一 first
- 如果下游止回阀受到污染,则可能从排气口泄漏到大气中,因此止回阀总成就要位于出现故障时能够清晰可见的位置。 In the event of fouling of the downstream check valve, leakage would be vented to atmosphere thereby providing a visual indication of failure of the check assembly.
- 第一次 first
- 拆卸固定第一止回阀阀盖的四个螺丝。 Remove the four screws holding the first check valve cover.
- 受到 receive
- 污染 pollution
- 第一个 first
- 第一章 chapter one
- 组件包括:第一止回阀总成和阀盖O形环。 Kit includes: First check assembly and Cover O-ring.
- 环境污染 environment pollution
- 污染的 infectant
- 止回阀 check valve
- 第一步 step one
- 空气污染 air pollution
- 第一时间 very first time
- 白色污染 white pollution
- 第一名 gold medal winner
- 第一的 prima
