A multistage, centrifugal partial emissions pump with a first stage impeller, a final stage impeller, a first stage casing liner, one or more first stage discharge nozzles, a final stage casing liner, one or more final stage discharge nozzles, an interstage delivery channel liner, one or more delivery channels, and an outer pressure shell wherein the first stage casing liner and the final stage casing liner are connected by one or more fluid channels integral within a delivery channel liner, that follow an arced path directed predominantly radially inward within the interstage delivery channel liner, and the sum of the cross sectional areas of all delivery channels taken on a radial plane intersecting the delivery channels is less than the sum of cross sectional areas of the non-channel areas within the boundaries of the channels.