escape valve

基本解释

China needs an escape valve.
中國需要一個“放氣閥”。
www.common-talk.com
He continues a long-standing artistic tradition of imagining the end of civilization, a form of emotional and spiritual escape valve operated since man found a means to express himself.
他長期以來保持著對文明終結的藝術性想象，這是一種情感和精神的宣泄形式，竝以此表達自我。
The engineer opened the safety valve to allow the steam to escape and so reduce the pressure.
手輪、手柄和扳手傳動以及安全閥、減壓閥、疏水閥省略本代號。

The proposed New York legislation includes an escape valve, but it requires a super-majority vote (60%) to raise taxes by more than 2% in a year.
FORBES: Property Tax Caps and Local Governance
Note the caveat: there must be an escape valve.
FORBES: Property Tax Caps and Local Governance
They do not have the safety-valve of banking books, where souring assets can escape the rigours of mark-to-market accounting.
ECONOMIST: Investment banking: Is there a future?