Container mounted pump with improved check valve structure

A pumping-head structure comprising a nozzle head, a piston, a first spring member, a liquid accumulator, a delivery tube, a fastening ring and a container cap;

• said nozzle head comprising a nozzle tube, an axial portion, an outlet and a pipe, said pipe being in said axial portion of said nozzle head, and said pipe being in communication with said nozzle tube;
• said pipe having a lower end which is fastened to said piston;
• said piston having a lower end and said first spring member having a lower and an upper end, said upper end of said first spring member being attached to said lower end of said piston;
• and said first spring member and said piston being mounted in said liquid accumulator;
• said liquid accumulator having a flange for mounting a container cap;
• said container cap is fastened in place by a fastening ring by which said container cap is fastened in a position between said fastening ring and said flange;
• said liquid accumulator having a lower end and said delivery tube being fastened to said lower end of said liquid accumulator, and said lower end of said liquid accumulator having an inlet;
• said pumping-head structure being characterized in that said inlet at said lower end of said liquid accumulator is installed with a valve annulus, said valve annulus having a top and a center, wherein said top of said valve annulus has a round groove for engaging with said lower end of said first spring member so as to fix said valve annulus in place;
• said center of said valve annulus is attached with a plunger valve via a second spring member, said second spring member exerts a downward force on said plunger valve and thus maintains said inlet tightly closed under normal conditions by a downward action of said plunger valve against said inlet.