The present invention relates to a valve device for a compressed gas container and, more particularly, to a valve device for a container containing a compressed gas and a product to be dispensed by action of the compressed gas.
Such valve devices are known in the art. One of such devices is disclosed for example in the German patent document DE OS 43 08 068. In this document a valve device is formed so that at the end of a product dispensing process and at the end of the actuation of the valve device, a small quantity of a driving agent is blown in the gaseous form from the head chamber of the container through a stem and a spraying head. Thereby the content of the stem and the spraying head is emptied with high pressure, and the stem and the spraying head are cleaned after the product dispensing operation. Therefore deposits in these parts are prevented.
The known valve device has a disadvantage that in the event of inexperienced use or in the event of clamping of the stem in a position located close to the upper position, an undesired gas escape from the pressurized container can occur, even a complete emptying of the container, since blowing out of the gas is performed during passing of this position by the stem. On the other hand, the known valve device has the disadvantage that additionally before the beginning of the dispensing of the product, a cleaning process is performed. This cleaning process is not needed since before, during ending of a product withdrawal, a cleaning process was already performed. The second cleaning process leads to excessive gas loss.