Closure for the metered addition of a separate liquid substance

A closure device for a metered addition of a liquid substance packaged separately in the closure device into a container (26) equipped therewith and containing a gas releasing liquid, the closure device comprising a connector sleeve (1) and a twist cap (2) fitting thereon from above in an air-tight manner, wherein the liquid substance is enclosed between the connector sleeve (1) and the twist cap (2), the connector sleeve (1) holds a cup (7) via an inner overhang (6), the cup (7) extending into a connector (5) of the container (26) and including at least one opening (9) at a bottom thereof, the opening (9) having such a small dimension that when a pressure above and below the opening (9) is the same, the liquid substance in the cup (7) is prevented by capillarity from flowing through the opening (9) into the container (26), and wherein the liquid substance is stored in a separate, foil-sealed substance cup (31) which is inserted upside-down in a nipple (14) integrally formed on an inside of the twist cap (2), with a foil (27) pointing downward, wherein the nipple (14) extends downwardly past the substance cup (31) and has an internal thread (28) on which a piercing and cutting mechanism (30) having upwardly directed cutting tips (29) is rotatably supported;

• the cup (7) tapering downward conically toward the opening (9) and, in an interior of a conically tapering base of the cup (7), upwardly extending retaining rods (33) are integrally formed and the retaining rods (33) penetrate the piercing and cutting mechanism (30) and secure the piercing and cutting mechanism (30) from rotating relative to the cup (7), so that when the twist cap (2) and the nipple (14) integrally formed thereon are rotated in a loosening direction, the piercing and cutting mechanism (30) is moved upward by a threaded connection and without rotating, to open the foil (27) using the cutting tips (29), and wherein when the twist cap (2) is further loosened, thereby carrying along the connector sleeve (1), a pressure of an interior of the container (26) and a pressure of the ambient air equalize and, due to a higher pressure in the cup (7) the liquid substance is pressed out of the cup (7) through the opening (9) into the container (26).