Abstract: A cap for a container having a body and a closure. The body has a side wall and an adjoining top. The Side wall has means to let gases escape from the container to ambient. The top has an interior and at least one recess on the interior. The body further has a a line juxtaposed to the interior of the top. The interior and the liner are pierced by a hole through which a tubular part extends from the body. The sealing means maintains the liner pressed against the interior of the top in a leak-tight manner. The closure is a flip-top cap.

Abstract: In a system comprising a container and a liquid contained therein that builds up a gas or vapor pressure, a sealing valve having a concave shaped portion and a slit extending through said portion, allows venting of the vapor from the container to the ambient at a predetermined vapor threshold pressure. The vapor threshold pressure at which the slit opens for venting can be adjusted by valve restraining means which are preferably formed by a protrusion at the inside of a cap covering the sealing valve. The vapor threshold pressure at which venting takes place, can to a large extent be adjusted without affecting the dispensing characteristics of the valve.