我院1988年8月引进了西德多尼尔HM-4型体外冲击波碎石机,该机是由双侧X线定位,属水囊型液电冲击波碎石机。自运行以来,冲击波次数已达130万次。在1年半的维修实践中,我们统计了已发生的大小故障21起,从故障的分布看认为已渡过了早期故障期,进入故障率较低的故障偶发期(见附图)。从图中可以看出,1989年7、8、9月份的故障率较高,估计是因 Our hospital in August 1988 the introduction of West Germany DORNIER HM-4 extracorporeal shock wave lithotripsy machine, the aircraft is located by bilateral X-ray positioning, is a hydrogel shock wave lithotripsy machine. Since its inception, the shock wave has reached 1.3 million times. In a year and a half of maintenance practice, we counted 21 faults that occurred, and considered that the fault period had passed the early fault period and entered the sporadic fault failure rate (see the attached figure). As can be seen from the figure, in July, August and September 1989, the failure rate is high, which is estimated to be due to