Check valve

A check valve comprising:

• a first hose connector housing defining an entry passage extending into an entry space at least partially defined by an annular valve seat;
• a second hose connector housing coupled with the first hose connector housing, the second hose connector housing defining an exit passage, the second house connector housing defining a series of discontinuous circumferential protrusions extending generally toward the entry passage;
• and
• a generally flexible membrane disk positioned between the first and second hose connector housings such that the membrane disk engages the protrusion and selectively engages the valve seat, the membrane disk defining at least one opening located radially outwardly from the valve seat, where the membrane disk is configured to be movable between a seated position, where the entry space and the exit passage are fluidly sealed from each other, and an unseated position, where the entry space and the exit passage are fluidly connected via the at least one opening;
• wherein the valve seat is located radially outwardly from the protrusion such that an unseating pressure required to move the membrane disk from the seated position to the unseated position is at least partially determined by the radial distance between the valve seat and the protrusion.