摘要
安全切断阀的一个众所周知的术语是紧急切断阀，或者简称作ESD阀。ESD阀的功能是根据停车系统的要求关闭阀门，因此执行的是一个关键的安全功能。紧急停车系统可以追溯到阀门安全系统的时代，阀门安全系统由第一层保护（紧急停车系统本身）和第二层保护组成，第二层保护是指安全泄放系统（安全泄放阀）。如果过程控制系统失灵，ESD系统将试图停车。如果停车失败，泄放阀触发，把压力、或者温度降低到一个可以接受的水平。
Awell-known term for the safety shutdown valve is the emergency shutdown valve, or ESD valve. The function of the ESD valve is to close upon a demand of the shutdown system and therefore performs a key satety function. The ESD system dates back to the time when valve safety systems consisted of a first layer of defence （the ESD system itself） and a secondary layer, which was the safety relief system （safety relief valves）, If the process control system failed, the ESD system would try to shutdown the process. If this failed, the relief valves triggered and reduced the pressure, or temperature, to a more acceptable level.
