Design of hydraulic circuits for the automatic operation of heliostats

An automatic hydraulic/thermal system for powering a tracking mechanism of a heliostat comprising at least a first means for sensing solar radiation and for selectively creating a first signal fluid pressure in response to said solar radiation, said first sensing means coupled to a first hydraulic logic circuit, said first means for sensing disposed adjacent to a first opaque shield such that said opaque shield is disposed between said sun and said first means for sensing, said first opaque shield for casting a shadow, said shadow for alternately covering portions of said first sensing means as said sun moves across the sky to indicate the relative position of said sun and for creating a specific first fluid signal pressure in response thereto, said first fluid signal pressure for energizing said first hydraulic logic circuit and for activating said first mechanical means for aligning said heliostat so as to receive direct radiation from said sun, said first sensing means comprising at least one pair or phials, each disposed within an evacuated transparent envelope and disposed from a base reference line and angle of .alpha..degree. and (180.degree.-.alpha..degree.) respectively where .alpha..degree. is between (0.degree. and 90.degree.,) said at least one pair of phials coupled one to one end and the other to the other end of a diverting valve in said first hydraulic logic circuit, as said shadow from said first opaque shield covers one of said phials of at least said one pair of phials a pressure differential is created between said at least one pair of phials, said pressure differential being identified by said diverting valve for transmitting a signal to said first hydraulic logic circuit for reacting to said pressure signal and for activating said first mechanical means to position said heliostat into proper alignment with said sun so as to receive direct solar radiation.