US Patent 7195138 Container closure with biased closed valve

A closure is removably attachable to a container and comprises a dispensing orifice and a valve element that is biased closed over the orifice. By inverting the container so that a liquid contents of the container exerts pressure on the valve element, or by squeezing the container causing the liquid contents to exert pressure on the valve element, the valve element opens the dispensing orifice allowing the liquid contents to be dispensed from the container. On removing the pressure from the valve element, the valve element resiliently closes the dispensing orifice.