Dish antenna structures and hydraulic control of the orientation thereof

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS The dish antenna 10 illustrated in FIGS.
1 and 2 was designed by the present inventors and has been assembled at The Australian National University, in Canberra, Australia.
It comprises a dish 12 constructed using a number of reflecting dish segments or panels 31 which are mounted on a dish supporting frame 15.
The dish 12 is a spherical reflector having a hexagonal periphery.
The shorter edges of the hexagonal periphery are 21.
8 meters long and its longer edges are 24.
7 meters long.
The dish has an aperture of 400 square meters.
If this dish should focus the sun (which subtends an angle of about 0.
5.
degree.
at the earth) sharply, the sun's image would have a diameter of approximately 14 cm.
Such an image of the sun would create such a concentration of energy at the focus that most materials used in equipment to harness the sun's energy would be damaged.
Thus the dish 12 is designed to form a "fuzzy" image of the sun, having an area of about five times the sharply focused image, at its focal region.
A "receiver" 13 of the solar energy, which is supported by struts 21, is positioned at the focal region of the dish 12.
In the solar collector built by the present inventors, the receiver 13 comprises a coiled tube which is used to generate high quality steam (that is, steam at high pressure and high temperature--although the temperature of the steam is limited by its application, for most steam turbines cannot accept steam at a temperature in excess of 500.
degree.
C.
).
It is emphasised that the embodiment of the present invention featured in FIGS.
1 and 2 is but one example of an implementation of the present invention, and the present invention is not limited to solar energy collectors generally, or to antenna configurations which are similar to that illustrated in FIGS.
1 and 2.
The dish supporting frame 15 is pivotally connected by a horizontal tilt axis 14 to a base frame 11 of the antenna structure.
The elevation of the line of sight 32 of the dish antenna is controlled by movement of the dish 12 and its support frame 15 about the tilt axis 14 using a hydraulic ram arrangement 16 which controls the movement of a sub-frame 17 that extends from the dish support frame of the solar collector antenna