Abstract: Liquid transport system with constant fluid flow rate provided by cam driven pump. Multiple cams on common cam shaft are driven by a source of constant power and coordinate timing and operation of multiple system elements.

Abstract: A fluid flow system for use with an analytical instrument is provided having a sample reservoir for holding a liquid suspension of particles to be analyzed, a reagent reservoir for holding a reagent, pump means for pumping fluid to and from the reservoirs to a pumping reservoir, valve means for restricting fluid flow from the reagent reservoir to the pumping reservoir, first conduit means interconnecting the reagent and sample reservoirs, second conduit means connecting the sample and pumping reservoir at a point just behind a metered aperture provided in an end of the second conduit means, and in a preferred embodiment, third conduit means connecting the first and second reservoirs and valve means for restricting fluid flow from the reagent reservoir to the pumping reservoir through the third conduit means, the end of each of the conduit means being maintained at the same physical level.