The method of stress analysis for pipe with special joints including Y joint and taper - taper joint is indicated through the analysis of vacuum transfer line.
The invariablenes condition of circle girth of the join-line end of the main pipe was set up and the join-lines on Y-tee to be ellipse was made certain.
建立了圆柱分支管y型三通的主管相贯线处的周长不变的条件，确定了相贯线为椭圆。
3
The procreative blanking plug of the "Y type" pipe string has check valve function and it can conveniently for reverse circulation well cleanup.