常用的直动式除鳞和先导溢流式除鳞阀存在启闭时产生较大的压力冲击，或启闭时间不可调的缺陷。
The common directly-acted descaling valve and pilot overflow descaling valve suffered from a defect that a greater pressure percussion produced at the time of opening and closing or the opening and closing time can not be adjusted .
鳞式