emergency relay valve

例句：

1. 1. The emergency relay valveis designed to prevent the system from shutting down during an emergency.
   紧急备用阀的设计是为了在紧急情况下防止系统停机。
2. 2. Theengineers replaced the old emergency relay valvewith a new one.
   工程师们用一个新的来替换旧的紧急备用阀。
3. 3. The valvewas tested before it was installed in thefactory, ensuring that it would work properlyduring emergencies.
   在工厂安装之前，阀门进行了测试，确保在紧急情况下能够正常工作。