Two-way pressure relief valve for blood reservoir

A medical fluid reservoir system, comprising:

• a reservoir shell, the reservoir shell defining an interior space inside of the reservoir shell that is configured to contain a medical fluid and an exterior space that is outside of the reservoir shell;
• and
• a differential pressure relief valve that is coupled to the reservoir shell, the differential pressure relief valve comprising:
• a housing body forming a recessed chamber with an upper opening and first and second subchambers side by side in fluid communication, wherein the first subchamber defines a positive pressure port comprised of a first opening in a bottom surface of the housing body with a first valve seat in the first subchamber along an inner perimeter of the first opening, and wherein the second subchamber defines a negative pressure port comprised of at least one second opening in the bottom surface of the housing body with a second valve seat on the bottom surface of the housing body along an outer perimeter of the second opening;
• a diaphragm member biased against the second valve seat and configured to deflect off of the second valve seat in response to a predetermined negative pressure;
• a sealing ball gravitationally biased against the first valve seat and configured to raise off of the first valve seat in response to a predetermined positive pressure;
• and
• a cover sheet disposed at an upper surface of the housing body to partially enclose the chamber and trap the sealing ball in the first subchamber, wherein the cover sheet includes an aperture aligned with the second subchamber providing an ambient pressure port coupling the chamber to an ambient atmosphere.