First: to act as an automatic non-return valve by preventing a backflow of steam from the main steam header to the boiler.

首先，能过作为一个自动逆止阀，防止蒸汽从主蒸汽加热器上倒流到锅炉里。

youdao

First: to act as an automatic non-return valve by preventing a backflow of steam from the main steam header to the boiler.

首先，能过作为一个自动逆止阀，防止蒸汽从主蒸汽加热器上倒流到锅炉里。

youdao