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.