Abstract: Powder is continuously circulated through a conduit loop, which has an enlarged section to increase powder turbulence, whereby the powder acquires a substantial electrostatic charge. Communication is then established with a second conduit section in which an article to be coated has been positioned to effect coating by the charged powder.

Abstract: An improved means for biological treatment of sewage characterized in the provision of a single aerating device feeding waste water serially into first and second settling chambers. The aerating chamber has a horizontal sectional area which generally increases in size from a relatively smaller horizontal sectional area at the bottom of a relatively larger horizontal sectional area at the top. The aeration chamber is characterized in the introduction of relatively large air bubbles within the water being aerated. The larger bubbles tend to move more quickly to the surface of the liquid being aerated, thereby increasing normal water movement and achieving more rapid oxidation. Plural settling chambers are connected by passageways to the aeration chamber, and an aerator in the aeration chamber causes recirculation of activated sludge from both chambers through the passageways, thereby treating in succession and maintaining sludge loss in the effluent at a minimum.

Abstract: The specification discloses a means and method for electrostatic coating of objects with synthetic resinous powdered material in which increased electrostatic charges are placed upon the powdered coating material before they are moved through the vicinity of the article to be coated by subjecting them to acceleration in a closed circuitous path from which they are tapped for movement to the coating area.