Abstract: An adjustable pump includes a ring connected to an open end of a container, a cap rectilinearly movable relative to the ring to dispense fluid from the container, and a quantity-adjusting unit that includes a limiting element and a knob. The limiting element is adapted for contacting the cap and hence limiting the rectilinear movement of the cap relative to the ring. The limiting element is rectilinearly movable relative to the ring to adjust a stroke of the movement of the cap relative to the ring. The limiting element includes at least one boss. The knob is rotatable relative to the ring around the limiting element. The knob includes at least one helical groove that receives the boss so that the limiting element is moved relative to the ring as the knob is rotated relative to the ring.

Abstract: A pump includes a collar, a cylinder and an elastic valve. The collar includes a wall, a tubular insert extending in the wall, and a connective portion formed between the wall and the tubular insert. The cylinder includes first and second open ends, first and second chambers respectively in communication with the first and second open ends, and a neck in communication with the first and second chambers. The elastic valve includes a ring, a plug extending in the ring, and elastic strips formed between the plug and the ring so that the plug is movable relative to the ring. The tubular insert is inserted in the first chamber via the first open end when the cylinder is connected to the wall, and the plug normally blocks the neck to form a first check valve when the elastic valve is connected to the second chamber.