escape valve

基本解释

China needs an escape valve.
中国需要一个“放气阀”。
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.
他长期以来保持着对文明终结的艺术性想象，这是一种情感和精神的宣泄形式，并以此表达自我。
The engineer opened the safety valve to allow the steam to escape and so reduce the pressure.
手轮、手柄和扳手传动以及安全阀、减压阀、疏水阀省略本代号。

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?