一级减压阀， 二级减压阀 的英文翻译怎么翻

primary pressure reducing valve 一级减压阀
secondary pressure reducing valve 二级减压阀

A valve， two valves

first level relief valve
second level relief valve

一级减压阀:reducing valve level-1
二级减压阀:reducing valve level-2

primary relief valve
secondary relief valve