Abstract: A body fluid drainage device that includes a wedge-shaped reservoir evacuator which has a first sidewall and a second sidewall integrally formed and joined along a coextending common edge. A third collapsible bellows-shaped sidewall extends between the nonjoined edges and is sealed to the nonjoined edges of the first sidewall and second sidewall to enclose and form a fluid tight reservoir between the first, second and third sidewalls. An inlet port and outlet port are provided in fluid communication with the reservoir. A one-way valve is provided in the inlet port for permitting fluid flow into the reservoir but preventing fluid flow out of the inlet port. A spring element is provided for storing energy to force the first sidewall away from the second sidewall following compression of the first sidewall towards the second sidewall such that as the first sidewall moves away from the second sidewall a partial vacuum is created within the reservoir for drawing fluid into the reservoir.