Abstract: A solar energy heating apparatus comprising means for concentrating solar energy incident thereon at an absorption station, an absorber located at the said absorption station for absorbing solar energy concentrated thereat, a first passageway associated with the said energy concentrating means for directing fluid so as to be preheated by the proportion of the incident energy absorbed by the said means, a second passageway associated with the absorber for effecting principal heating of fluid directed therethrough, the second passageway being such that on directing fluid through the first passageway it is initially preheated by the proportion of the incident energy absorbed by the said energy concentrating means, the preheated fluid thereafter being directed to the second passageway where the principal heating takes place.

Abstract: A fluid operated control device which co-operates with reciprocating means, such as a pneumatically driven shaft. The device includes a main cylinder and piston backed at each end by valves which each include auxiliary cylinders and pistons. The valves provide signal inlets and outlets which can be cross connected to cause continuous reciprocation of the main piston. Alternatively, the valves are operated to displace the main piston selectively or are connected to a delay to vary the timing sequence. Stroke adjustment is possible by a rod attached to one of the auxiliary valves. The main piston is mounted on a shaft passing through the other auxiliary valves.