The present invention provides a downhole cementing apparatus run into a borehole
on a tubular. The apparatus is constructed on the pipe in such a way that pressure
surge during run-in is reduced by allowing fluid to enter the pipe and utilize
the fluid pathway of the cement. In one aspect of the invention, an inner member
is provided that filters fluid as it enters the fluid pathway. In another aspect
of the invention, various methods are provided within the cementing apparatus to
loosen and displace sediment in the borehole prior to cementing.