The Protected Valves Model Container is designed for mechanical filtering and requires no maintenance. The valve is kept in a state of rest before the sterilization process. During and after sterilization, it has three working positions. Correct functioning may be controlled by inserting a tip in the appropriate hole in the middle of the valve bottom. During the vacuum stage, the valve opens completely due to depression. This results in air escaping the container. After this occurs, the valve closes and a second one opens up, which allows steam to enter. This is when the sterilization process begins.