preaction valve是什么意思

网络释义

1)preaction valve,预作用阀2)valve action,阀作用3)self-operated valve,自作用阀4)application pilot valve,作用导阀5)reactive valve,反作用阀6)application valve,作用阀

Reason analysis of the trouble with JZ-7 air brake application valve and its precautions

JZ-7型空气制动机作用阀故障的原因分析与防止办法