Mchanical tee can be directly used to connect the branch pipes with the main steel pipe. Firstly, to open the hole with hole-cutting machine on steel pipes ,and clip the mechanical tee into the hole, around which are sealed by the gasket rings .Mechanical tee are categorized as threaded style and Grooved style. When be connected ,the threaded mechanical tee should be applied with some compacting paint on it′s outer screw thread ,and then roll thread around it to ensure the sealing performance of threaded joint.