A solar shutter system including a pair of insulating panels pivotally mounted adjacent a glazed opening. Insulated and uninsulated counterbalance pressure tanks are mounted at opposite ends of one of the panels. The counterbalance tanks are interconnected by tubing and contain a partially vaporized...http://www.google.fr/patents/US4349011?utm_source=gb-gplus-shareBrevet US4349011 - Solar operated shutter
