性能特点：
     1、能提供最准确的低压和真空防护。
     2、软密封的主阀瓣能在95%以上的开启压力范围内获得高密封度。
     3、导阀可在主阀以外单独调定开启压力和关闭压力。
     4、排放量是相同进口通径安全阀的1.25倍。
Features:
1) Provides the most exact low-pressure and vacuum fence
2) Soft airproof main valve can obtain high airproof performance in the scope of over 95% lift pressure
3) Pilot valve can adjust lift and close pressure solely out of main valve
4) Capacity is 1.25 times as the same inlet safety valve