An analysis method is suggested for the data obtained in the check of buried pipeline locations in order to evaluate the detection quality of pipeline location in whole detection area.

The significance of concealed work,the main forms of concealing,causes of problems concerning concealed work,as well as means dealing with them are expounded.

Through the numerical simulation,the internal flow fields of jet pump are calculated under the condition of different throat lengths and the optimal sizes of throat are obtained.

This paper presents ample experimental data which show that the improvement ofwater-jet pumps from short throats into long ones costs a little work and expense and the im-proved throat is efficient and energy-saving.

No packer is installed at the bottom end of the jet pump within which a group of nozzles and throat diffusers are installed.