Abstract: In a method of treating a liquid, a liquid to be treated is introduced into a space, a mechanical cavitation element acts upon the liquid while gas is supplied into the region of the surface of the cavitation element and introduces the gas into the liquid by moving the cavitation element, and sound waves are introduced directly into the liquid by at least one acoustic power transducer.

Abstract: In a method of treating a liquid, a liquid to be treated is introduced into a space, a mechanical cavitation element acts upon the liquid while gas is supplied into the region of the surface of the cavitation element and introduces the gas into the liquid by moving the cavitation element, and sound waves are introduced directly into the liquid by at least one acoustic power transducer.

Abstract: The description relates to an actuator for use at high and low temperatures, with a cylinder block (8), a piston (14) movable therein and a piston rod (22) secured to the piston. A first and a second flange cover (46, 48) and a sleeve (40) in the cylinder block (8) in which the piston (14) can move to and fro are made of ceramic. The piston rod (22) is secured to the piston (14), also of ceramic, by a head bearing (24) movable transversely to the longitudinal axis of the piston. The seal between the piston (14) and the sleeve (40) is provided solely by a close fit, without the need for additional sealing components. The low thermal expansion of the ceramic components used also means that the tolerances change little even at great temperature fluctuations. The radial head bearing (24) prevents the piston (14) from jamming during forces transverse to the longitudinal axis of the piston possibly arising at the piston rod (22).

Abstract: A solar heated building comprising a frame, an inner wall supported by the frame, and an outer wall of generally transparent material supported by the frame and spaced outwardly of said inner wall thereby defining a passage therebetween. The passage has an inlet for the flow of air into the passage and an outlet in communication with the interior of the building for flow of air from the passage into the interior of the building. The inner and outer walls are positioned for incidence thereon of solar radiant energy, whereby on flow of air through the passage the air may be heated by the solar radiant energy prior to flowing into the interior of the building.