Abstract: The object of the invention is to provide a method of treating wash water resulting from the scrubbing of process gases in smelting plants, according to which method the wash water is brought into intimate contact with the process gas and is circulated when the solids have been deposited. The method according to the invention draws off a partial flow from the wash water, mixes it with fresh water and uses it for rewashing the process gas. According to the invention, the wash water necessary for the scrubbers is drawn from a wash water container. In the sedimentation tank the insoluble portions are removed from the substance-charged wash water which is then introduced into the wash water container. The wash water required for the rewashing stage is removed from the wash water container and mixed with fresh water via the fresh water pipe.

Abstract: A control system for hydrofoil craft is one in which control surfaces are moved automatically in response to signals derived from the motion of the craft to stabilize and control the craft. In such systems, a potentially dangerous condition can occur in case of a failure or malfunction in the roll control system. In order to prevent such conditions, two roll sensing devices are provided which normally generate identical signals to actuate the control surfaces to stabilize the rolling motion. In case a failure or malfunction, the signals provided by the two sensing devices become different and apparatus is provided to compare these signals and to respond to a difference in the signals to initiate landing of the craft rapidly and safely.