A housing for a surveillance camera is generally dome shaped, the camera being movable therein, and the interior of the housing is under pressure to exclude contaminants. The housing is made up of an assembly plate having a central opening to receive a lower dome therethrough, with an upper...http://www.google.es/patents/US5852754?utm_source=gb-gplus-sharePatente US5852754 - Pressurized housing for surveillance camera
