A pump assembly includes a cylinder open on top and bottom thereof and having a hollow portion formed therein and a first wing protruding outward from the outer peripheral surface of top thereof, a sealing part having at least a portion thereof inserted into the cylinder to at least partly seal the upper peripheral surface of the cylinder and a second wing protruding outward from the outer peripheral surface of the top thereof, a stem moving downward in reply to an external force to vary internal pressure of the cylinder, an elastic member disposed between the stem and the sealing part to apply an elastic force to the stem from the sealing part, and a housing coupled to the cylinder in such a way to surround the outer peripheral surface of the upper portion of the cylinder and adapted to detachably couple the pump assembly to a container.

A pump dispenser having a bottle with a neck and a pump assembly. The pump assembly includes an actuator, a closure connected to the actuator and coupled to the neck of the bottle, a dip tube, and a dual chamber pump. The dual chamber pump includes a piston assembly, a sealing cap, and a housing, which includes a pump chamber, a storage chamber having a cavity, and a core. The sealing cap is rigidly connected to the core and closes the storage chamber at a lower portion such that the substance to be released remains stored in the storage chamber cavity. When the actuator is pushed down for a first time by a user, a piston assembly moves to push down a connecting stem, which pushes down the sealing cap to open the storage chamber for releasing the substance contained in the storage chamber from the bottle.