Connect the vacuum pump to the compound pressure gauge; open the compound pressure gauge and vacuum pump to vacuum the indoor unit and connecting pipe.
将真空泵连于复合压力表，打开复合压力表和真空泵对室内机和连接管抽真空。
2
The plumber packed the joint of the pipe with string and a special compound.
这个装修水管的工人用绳子以及一种特殊的复合物把管子的接头包垫起来。
3
Extrusion die design for compound triple-layer plastic pipe by two extruding machines is introduced.