Improved After analysis of valve problems, its structure, operation and environment was improved.

改进经过分析阀门存在的问题，对其结构、止回阀操作及环境进行了改进。

youdao

Improved After analysis of valve problems, its structure, operation and environment was improved.

改进经过分析阀门存在的问题，对其结构、止回阀操作及环境进行了改进。

youdao