A high pressure transfer device has a rotor mounted in a housing for rotation with respect to inlet and outlet ports and having through going pockets. The pockets have interior surface configurations substantially devoid of nooks, crannies, and related flow restrictions. This can be accomplished by providing inserts in the pockets, or by constructing the pockets so that there are substantially smooth interior wall tubes extending from one end of the rotor and the other and cooperating with an inlet and an outlet at the same time. Using the high pressure transfer device to feed wood chips or the like in a slurry using a high pressure transfer pump can result in flow through the rotor pockets that is more uniform by at least 5% compared to in conventional high pressure transfer devices.