Abstract: A portable pumping system for administering fluids intravenously to a patient. The system has a tube connected between the fluid source and the patient with one-way valves at each end of the tube to limit the flow to one direction. A middle portion of the tube is positioned within a first chamber that is connected by a hose to a second chamber. The second chamber has a flexible member that is reciprocally moved by an arrangement that includes a housing and a source of compressed gas. The housing has a valved inlet and outlet and the flexible member forms a portion of the boundary of the housing. The valve for the outlet of the housing is attached to the flexible member which is a metallic disc inherently biased in a concave shape in relation to the housing. In operation, the flexible member inverts to a convex shape as pressure increases within the housing emitting a click.