Gas spring solar tracker

Apparatus for tracking the sun comprising:

• a base fixed relative to the earth;
• a frame pivotably attached to the base so that the frame has an east end and a west end and is pivotable about a generally north/south axis, the axis being inclined to horizontal to direct the frame toward the path of the sun;
• small and large elongate cannisters at the east and west ends of the frame respectively parallel to the pivotal axis of the frame so that one end of each cannister is lower than the other end of such cannister, the small cannister having a volume V.sub.S smaller than the volume V.sub.L of the large cannister;
• a pair of shadow bars over the respective cannisters, each shadow bar extending from a position on the side of the cannister opposite from the pivotal axis of the frame to a position immediately over the centerline of the cannister;
• a conduit providing fluid communication between the low ends of the cannisters and having a volume V.sub.C ;
• a quantity of volatile fluid in the cannisters and conduit which is a liquid at ambient temperatures having a volume V.sub.F defined by the limits V.sub.S +V.sub.C <V.sub.F <V.sub.L, movement of the sun from east to west heating the small cannister to raise the vapor pressure of the volatile fluid in the small cannister and force the liquid content of the fluid into the large cannister and tilt the frame eastward to follow the sun;
• and
• a gas spring fluid in the west cannister having a vapor pressure sufficient to force the volatile fluid to the small cannister in the absence of sunlight so that the frame tilts back toward the small cannister at night in preparation for the morning sunrise.

A louver system for providing shade from sunlight comprising:

• a plurality of louvers pivotable about parallel axes;
• means for interconnecting the louvers so that said louvers pivot in unison;
• a small cannister having a volume V.sub.S located along the back edge of one of the louvers;
• a large cannister having a volume V.sub.L larger than V.sub.S mounted along the front edge of one of the louvers;
• means for shading the large cannister from the sun;
• a conduit providing fluid communication between the cannisters and having a volume V.sub.C ;
• a quantity of volatile fluid in the cannisters and conduit having a liquid volume V.sub.F defined by the limits V.sub.S +V.sub.C <V.sub.F <V.sub.L, so that sufficient solar heating of the small cannister relative to the large cannister forces all of the liquid volatile fluid from the small cannister to purge it of foreign gasses;
• and
• a gas spring fluid in the large cannister having a vapor pressure sufficient to force the volatile fluid into the small cannister.

Apparatus for exposing a medium in the presence of sunlight and covering the medium in the absence of sunlight, said apparatus comprising:

• a cover;
• means for pivotably mounting the cover so that the cover is pivotable between a closed position overlying the medium and a open position which allows sunlight to strike the medium;
• a small cannister located at the front edge of the cover and having a volume V.sub.S ;
• a large cannister located at the rear edge of the cannister and having a volume V.sub.L larger than V.sub.S ;
• means for shading the large cannister from sunlight;
• a conduit providing fluid communication between the cannisters and having volume V.sub.C ;
• a quantity of volatile fluid in the cannisters and conduit having a liquid volume V.sub.F defined by the limits V.sub.S +V.sub.C <V.sub.F <V.sub.L, so that sufficient solar heating of the small cannister relative to the large cannister forces all of the liquid volatile fluid from the small cannister to purge it of foreign gasses;
• and
• a gas spring fluid in the large cannister having a vapor pressure sufficient to force the volatile fluid into the small cannister in the absence of sunlight so that the cover closes at nightfall and at other times when sunlight is not available, the cover being balanced so that movement of the volatile fluid from the small cannister to the large cannister when sunlight is available opens the cover.