先导式安全阀pilot operated safety valve（）

A、感测压力元件由原来的粗弹簧变为压力传感器(即先导阀)，从而提高阀的灵敏度和精度。The pressure sensor changes from the original coarse spring to the pressure sensor (i.e., the pilot valve), thus improving the sensitivity and accuracy of the valve.

B、采用笼式套筒阀芯和软密封结构，从而确保阀芯起跳后正确复位和密封好，克服了弹簧式安全阀关闭不严导致长期泄漏及过量排放等问题。Cage-type sleeve valve core and soft seal structure are adopted to ensure that the valve core is properly reset and sealed after take-off, thus overcoming the problems of long-term leakage and excessive discharge caused by the loose closing of spring safety valve.

C、安全阀泻放的气体应引入同级别压力的放空管线中，送到放空竖管排入大气。Relief valve discharge gas should be introduced into the same level of pressure of the vent line, sent to the vent riser into the atmosphere.

D、以上都不对