It has special unitized construction which consists of the seat, disc and stem assembly, and strainer screen all together in one unit for complete replacement maintenance.
它具有特殊的整体结构，由阀座，阀瓣和阀杆总成，以及过滤器网等整合在一个整体中，完全能够进行更换维护。
Unit 1, engaged in the construction site crane assembly and disassembly operation must obtain professional contracting qualification.
施工现场从事塔吊拆装作业的单位必须取得专业承包资质。
Unit 1, engaged in the construction site crane assembly and disassembly operation must obtain professional contracting qualification.
施工现场从事塔吊拆装作业的单位必须取得专业承包资质。
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