US Patent 7900398 Security door system

A revolving security door includes a drum defining a secure zone between door openings controlled by a revolving door disposed within the drum and wherein light curtain sensors and active infrared sensors may detect an intruder moving from a non-secure side of the doorway to the secure side and detect objects left behind in a secure zone. Methods of operation prevent persons or objects from passing from the non-secure side to the secure side of the doorway.