Valve for prefilled bone cement mixing system

An apparatus for mixing bone cement, the apparatus comprising:

• a mixing chamber configured to house a first component of the bone cement prior to mixing;
• a connecting cylinder defining a conduit configured to fluidly connect the mixing chamber and the connecting cylinder;
• a cannula located within the connecting cylinder and in fluid communication with the conduit;
• a base including a pouch configured to house a second component of the bone cement, a portion of the base sized to be received within the connecting cylinder such that upon a relative movement between the base and the connecting cylinder, the pouch is punctured by the cannula;
• a piston located within the mixing chamber and configured to engage the connecting cylinder;
• and
• a valve retained by the piston and configured to allow the second component of the bone cement to pass through the cannula from the pouch into the mixing chamber and collapse to seal the mixing chamber upon disengagement of the connecting cylinder from the piston, wherein the valve includes a projection extending from a base of the valve to a base opposing end thereof, the projection forming part of a passage that allows for passage of the second component through the valve when the valve is not in a collapsed state, and wherein the projection has a frustoconically shaped inner surface that forms a part of the passage.