在北京市郊区的深管机井上,多安装离心泵。水泵的吸水管以往有很多采用带底阀的胶管,伸入井管中动水位以下。这种安置型式的缺点是:胶管容易腐烂、折断或漏气,使用寿命短;底阀脱落不易打捞;砂石杂物容易落进井管并把吸水管的底阀卡在井管里。为了克服这些缺点,从1962年起,逐 In the suburb of Beijing deep wells, install more centrifugal pumps. Pump suction pipe in the past there are many with a hose valve at the end, into the well below the water level. Disadvantages of this type of placement are: perishable hose, broken or leak, short service life; bottom valve is not easy to salvage; sand and debris easily fall into the well pipe and the bottom of the suction pipe stuck in the well pipe. In order to overcome these shortcomings, from 1962 onwards