Medical administration set enabling sequential delivery of two liquids at different flow rate

Claim 1

A medical liquid administration set for the sequential administration of two medical liquid sources, which can be delivered at different liquid flow rates without readjustment of the set, the administration set comprising: (a) a first conduit including a proximal end for connection to a first liquid sources, and a distal end; (b) a second conduit including a proximal end for connection to a second liquid source, and a distal end, said second conduit being devoid of any gas barrier means; (c) a cross over branch having an upstream end in communication with said second conduit between said proximal and distal ends of said second conduit, and a downstream end in communication with said first conduit at said distal end of said first conduit, said cross over branch being devoid of any gas barrier means; (d) a common conduit including a proximal end in communication with both said distal end of said first conduit and said downstream end of said cross over branch, and further including a common conduit distal end, said common conduit distal end being in communication with said second conduit at said second conduit distal end, said common conduit being devoid of any gas barrier means; (e) a liquid outlet located no greater than about four inches downstream of distal ends of both said common conduit and said second conduit, there being no gas barrier means between said distal ends of both said common conduit and said second conduit and said liquid outlet; (f) a one-way valve in said cross over branch permitting liquid flow only in the direction from said upstream end to said downstream end; (g) a one-way valve in said first conduit permitting liquid flow only in the direction from said first conduit proximal end to said first conduit distal end; (h) adjustable liquid delivery rate control means on said second conduit, downstream of said upstream end; (j) whereby in operation said distal ends of said common conduit and said second conduit are disposed at an elevation lower than, equal to or not substantially higher than said liquid outlet.