According to its shaft seal structure, high vacuum flapper valve is classified into GD-J rubber shaft seal type and GD-J(b)bellows shaft seal type.是什么意思_According to its shaft seal structure, high vacuum flapper valve is classified into GD-J rubber shaft seal type and GD-J(b)bellows shaft seal type.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句