Abstract: An apparatus for enhancing chemical reactions in a constantly flowing stream of liquid character fortified with oxidizing agents, such as air or oxygen or other chemical agents, makes use of an inner resonant tube concentrically mounted within an outer resonant tube with the walls of the tubes spaced from each other forming an annular passageway for the flow of liquid from one end of the passageway to the other. One or more sets of radially spaced ultrasonic transducers are located on the outside wall of the outer resonant tube thereby to create an ultrasonic cavitation condition in the liquid as it flows through the annular passageway.

Abstract: A continuous self-cleaning filter for liquids has an outer resonant tube concentrically mounted around an inner composite tube in spaced relationship providing an annular chamber between them. There is an inflow at one end of the annular chamber for the liquid and an outflow at the other end for residual concentrate. The inner composite tube has an outlet at one end for clear effluent and a closed opposite end. A relatively thin walled perforate liner enveloped in a filter blanket comprises the composite tube.

Abstract: A guide for slidably accepting opposite edges of an electronic circuit board has a rotating clamp which is open to offer zero frictional resistance when the board is slid into position. The clamp is in effect a bar rotatably mounted in an elongated retainer, the bar having a camming action against the retainer so that when the bar is rotated the entire length of the bar is pressed against the board to anchor it in place.