The main agenda of the present work is to develop the inbuilt priming system for centrifugal inline pump which will be part of the centrifugal pump and could perform the priming function automatically without any external resource or additional machine. To develop this system, it is used the principle of vacuum pump which operates on the liquid ring vacuum principle. The main working fluid required for this priming pump is mixture of air and water. In this development work, it is designed the Casing chamber and impeller of vacuum pump arrangement on the same shaft of main centrifugal pump and will operate along with main pump. Water required for the priming unit is provided through external tank in priming chamber and air from the main pump and its piping will be made available for priming pump. Arrangement for service liquid and its piping in connection with vacuum pump is designed to perform the priming function automatically.