Low actuation pressure unidirectional flow valve

A low actuation pressure, unidirectional flow valve comprising:

• a housing including a fluid flow passage extending therethrough which defines first and second sections;
• and
• a valve member disposed within said housing between said first and second sections of said flow passage, said valve member comprising:
• an annular ring portion;
• a disc portion disposed within said ring portion;
• at least two connecting arm portions extending between said ring and disc portions in symmetrical relation to each other;
• and
• at least two side openings defined by said ring, disc and connecting arm portions;
• said valve member being movable between a closed position wherein said disc portion covers and seals the first section of the flow passage and an open position wherein said disc portion is separated from said first section and fluid flows from said first section to said second section via said side openings, the movement of the valve member between the closed and open positions being facilitated by the flexion of the connecting arm portions;
• said valve member being configured such that when in the open position, the combined cross-sectional area of the side openings exceeds the minimum cross-sectional area of the first section of the flow passage.