Abstract: A pipe is provided through which a fluid can move without backflow in the absence of a gravity force provided by a downward pitch. This is accomplished by providing within the pipe a series of one-way valves, each having a structure similar to a mitral valve, with a rigid upper flap cooperating with a semi-rigid but flexible lower flap. Fluid pressure upstream of the valve will displace the lower flap enough to allow fluid to accumulate in a reservoir area downstream of the valve and upstream of a ramp structure. When sufficient fluid accumulates in the reservoir area, it overflows the ramp structure and proceeds to the next one-way valve, and the process is repeated.