Security door system

A method of operating a revolving security door system, the door system comprising an arcuate drum defining an enclosure and opposed first and second openings, a revolving door disposed for rotation within the enclosure and including plural radially extending door wings, a secure zone within the enclosure, first sensor disposed generally along a radial line extending from an axis of rotation of the door to the enclosure for detecting an intruder or an object moving into the zone from the first opening on a non-secure side of the door system, a second sensor for sensing the presence of an object remaining in the zone, the method comprising:

• rotating the door to allow a person to pass from the second opening on a secure side of the door system to the first opening;
• generating a light curtain by the first sensor extending from the axis of rotation of the door;
• detecting with the first sensor an intruder or an object entering the zone;
• and
• arresting movement of the door in response to detecting the intruder entering the zone and maintaining the door in a position to allow the intruder to exit the zone through the first opening;
• detecting with the second sensor the presence of an object remaining in the zone;
• and
• moving the door in response to detecting no intruder in the zone and the presence of an object in the zone so as to close off the zone from the openings to prevent access to the object to the zone.