放汽阀, 安全阀

[ noun ]
a valve in a container in which pressure can build up (as a steam boiler); it opens automatically when the pressure reaches a dangerous level
<noun.artifact>

Escape \Es*cape"\, n.
1. The act of fleeing from danger, of evading harm, or of
avoiding notice; deliverance from injury or any evil;
flight; as, an escape in battle; a narrow escape; also,
the means of escape; as, a fire escape.

I would hasten my escape from the windy storm. --Ps.
lv. 8.

2. That which escapes attention or restraint; a mistake; an
oversight; also, transgression. [Obs.]

I should have been more accurate, and corrected all
those former escapes. --Burton.

3. A sally. ``Thousand escapes of wit.'' --Shak.

4. (Law) The unlawful permission, by a jailer or other
custodian, of a prisoner's departure from custody.

5. (Bot.) A plant which has escaped from cultivation.
[Webster 1913 Suppl.]

Note: Escape is technically distinguishable from prison
breach, which is the unlawful departure of the prisoner
from custody, escape being the permission of the
departure by the custodian, either by connivance or
negligence. The term escape, however, is applied by
some of the old authorities to a departure from custody
by stratagem, or without force. --Wharton.

5. (Arch.) An apophyge.

6. Leakage or outflow, as of steam or a liquid.

7. (Elec.) Leakage or loss of currents from the conducting
wires, caused by defective insulation.

{Escape pipe} (Steam Boilers), a pipe for carrying away steam
that escapes through a safety valve.

{Escape valve} (Steam Engine), a relief valve; a safety
valve. See under {Relief}, and {Safety}.

{Escape wheel} (Horol.), the wheel of an escapement.