Patent ID: 8376190

Claim:
In a foam discharge pump dispenser which includes a liquid storing container 10 in which a cap 20 is covered on an upper side of the same, a nozzle head 30 which is assembled to move up and down on an upper side of the cap 20 and has a foam discharge hole 31 , a foam filtering mesh 40 which is engaged in the interior of the nozzle head 30 , a piston cover member 50 which is fixed at a lower side of the nozzle head 30 and has an air and liquid mixing chamber 51 at an upper side of the same and an air opening and closing passage 52 formed at a lower surface of the same, an air chamber 60 which is engaged in the interior of the liquid storing container 10 and has an air inlet hole 61 formed at a side surface and a liquid cylinder 63 having a liquid inlet port 62 at a lower side, a piston member 70 which is engaged in the interior of the air chamber 60 and integrally includes an air compression piston 71 at an outer side, an air opening and closing step 72 and an air flow hole 73 at an inner side, a liquid flow path 74 at a center portion, a liquid opening and closing surface 75 at an upper inner surface, and a liquid compression piston 76 at a lower side of the same, a valve shaft 80 which is engaged in the interior of the liquid flow path 74 and has a valve support escape prevention enlargement part 82 formed of a liquid opening and closing enlargement part 81 at an upper end and a ball valve support engaging shoulder 83 at a lower end, a ball valve support 90 disposed at a lower end of the valve shaft 80 , a ball valve v disposed between the ball valve support 90 and the liquid inlet port 62 , and a return spring s disposed between the piston member 70 and the air chamber 60 , a foam pump dispenser having a leakage prevention function against a reverse flow, comprising: an air valve member 100 which is engaged at a lower side of the air and liquid mixing chamber 51 of the piston cover member 50 and is fixedly covered on an upper side of the piston member 70 ; an air opening and closing plate 120 provided on an upper side of an outer wall of the air valve member 100 ; an air valve guide member 300 which is fixedly inserted into an intermediate inner surface of the piston cover member 50 ; and a liquid leakage prevention valve 330 comprising the air valve guide member 300 and a liquid leakage prevention spring 200 disposed between the piston cover member 50 and the piston member 70 , wherein the liquid leakage prevention member 300 is covered on an upper side of the liquid compression piston 76 .