A damper comprises two cold air inlets through which a fluid flows, two gate plates which open and close the two cold air inlets and a drive unit for driving the two gate plates. The drive unit is installed between the two cold air inlets to open and close the gate plates. The drive unit operates to...http://www.google.es/patents/US6058726?utm_source=gb-gplus-sharePatente US6058726 - Damper
