Pressure energized pressure vessel opening and closing device and method of providing therefor

A closure assembly coupled to a vessel including a chamber and an access port for receiving a wafer, the access port in communication with the chamber, the closure assembly comprising:

• a. a door assembly coupled to the vessel and configured to move between an open position and a closed position, the door assembly in contact with the access port at a first location, thereby sealing the chamber in the closed position, wherein pressure within the chamber applies a force to the door assembly at the first location;
• and
• b. an actuator in moveable contact with the door assembly at a second location, the actuator configured to apply a counteracting force to the door assembly at the second location in response to pressure within the chamber and thereby maintaining the door assembly in the closed position, wherein the actuator is configured within an actuator bore, the actuator bore configured within the vessel and coupled with the chamber, the actuator configured to move between a non-actuated position and an actuated position within the actuator bore, the actuator in the actuated position when a desired amount of pressure is applied to the actuator bore.