Abstract: A digital valve unit comprised of a plurality of valve orifice sections which have orifice sizes in a binary relationship. The orifice sections are detachable from the valve unit such that the unit may be modified to have different size orifices in different combinations. The unit also comprises a plurality of stackable air powered actuators. The valve actuators may each comprise a single or multiple stage, depending on the application required.

Abstract: A sun tracker for use on a sun following device such as a concentrating solar collector. The sun tracker includes two spaced apart photosensitive elements which are separated by an opaque splitter plate so that when the splitter plate points directly at the sun the photosensitive devices are uniformly excited. The west facing surface of the splitter plate is reflective so that movement into alignment with the sun can be achieved even after long periods during which the sun is obscured by clouds. The outer edge of the splitter plate is arcuately formed so that excitation of the photocells is substantially independent of the angular orientation of the sun tracker.

Abstract: A solar energy reflector formed of a rigid frame that supports a thin reflective sheet and retains the sheet in a parabolic or like concave shape notwithstanding severe wind or like loads. The frame includes rigid end plates that define slots that have portions concentric with the focal axis of the parabolic surface so that the reflector can be installed onto and removed from a fixed water carrying pipe without disturbing the plumbing connections to the pipe. A drive system and solar energy sensor circuit connected thereto for assuring that the reflector is aimed at the sun throughout its traverse of the sky from dawn to dusk. A protective cover for the solar collector which both protects the highly reflective surface against deterioration and contributes to the overall strength of the collector.

Abstract: An array of photovoltaic cells and a parabolic concentrator for concentrating solar energy onto the cells. A watertight chamber including a solar energy pervious window adjacent the focus of the parabolic concentrator. The solar cell array is disposed within the chamber in alignment with the window. A quantity of water disposed in the chamber, the quantity being sufficient to absorb heat energy so as to limit the temperature rise of the solar cell array during periods of solar energy impingement thereon. The watertight chamber has sufficient external surface area that the heat energy stored therein is transferred away during non-solar energy producing periods of the diurnal cycle.