永久性密封 meaning in English
sealed-for-life
Examples
- Watts 994hmb fire hydrant backflow preventer meter construction consists of : meter housing , measuring element , permanently sealed register , and reduced pressure backflow preventer in unitized assembly
美国瓦茨994hmb消防栓防回流阀仪表结构包括：仪表壳，测量元件，永久性密封记录器，和在成套总成内的减压防回流阀。