Fluid drainage container

A fluid drainage device (10;

• 10A;
• 10B) for use in a closed wound drainage system which includes a body (12), with a cylindrical bore (26) which defines at least part of a fluid-receiving volume (60), an inlet (14) to the fluid-receiving volume (60), a piston (28), in sealing contact with the bore (26), which partly bounds the fluid-receiving volume (60), the piston (28) being movable between a first position and a second position, a piston rod (32) which extends from the piston (28), an energy storage device (34) engaged with the piston rod (32), a user-actuated handle mechanism (14) which is movable relative to the body in a first direction, to allow the piston (28) to move from the first position at the beginning of a working stroke where the frictional force is at a maximum value, whereby energy is stored in the energy storage device (34) to the second position at the end of a working stroke where the frictional force is at a minimum value whereby energy is released from the energy storage device (34) wherein the frictional force decreases as the piston (28) moves over;
• the working stroke from the maximum value to the minimum value, thereby increasing the size of the fluid-receiving volume (60), reducing the pressure in the fluid-receiving volume (60) and allowing fluid to flow from a suitable conduit through the inlet (16) and into the fluid-receiving volume (60).