Abstract: In order to inject oxygen into a liquid, for example, sewage, the installation is provided with an aerating system (2) that is arranged in an aerating basin (1).In order to improve the oxygen injection rate per kilowatt of driving force the aerating system (2) that is connected with a pump (3) in the manner of a water jet pump, the flow cross-section of which, in its air intake area, can be varied so as to change the oxygen injection rate. To this end, the diffusor stage (8) of the aeration system (2) extends along a conical surface. The hollow-configured conical diffusor inner portion (13) is arranged, together with a surface aeration impellor (16), on a common drive shaft (14), and can be moved along its longitudinal axis (15).

Abstract: A surface-aeration rotor is provided with a carrier-part connected to a vertical drive-shaft. Secured adjustably to the carrier-part are several liquid-conveying units each consisting of a scoop and two flow-guiding walls. In order to improve the oxygen-input performance per kilowatt of rotor-drive power, the liquid-conveying units are designed in such a manner that the scoops are disposed in a plane which is twisted and which is curved in the direciton of rotation of the rotor, whereby the jets of liquid emerge from the rotor standing on edge.

Abstract: The rotary surface aeration device used to rotate and aerate sewage is provided with a carrying part connected to a vertically running drive axle. A plurality of liquid transporting units also fastened to the carrying part.In order to improve the oxygen input, the liquid transporting units, which are adjacent to each other viewed in the circumferential direction of the rotary aerating device, have different jet exiting speeds. This is achieved by giving the scoop outlet edges of these liquid transporting units, which are adjacent to each other, a different distance (d, d') from the drive axle of the rotary aeration device. The liquid transporting units are arranged and constructed in such a way that the liquid jets of at least two liquid transporting units, which are adjacent viewed in the circumferential direction of the rotary aeration device, exiting from said units during the operation of the rotary aeration device strike each other before reentering into the liquid to be aerated.

Abstract: A surface aerating rotor has an intake zone for circulating and aerating a liquid, and includes a supporting assembly, a driving shaft connected to the supporting assembly, fixed flow guidance devices disposed in the intake zone of the rotor, and a plurality of fluid throughput units. Each fluid throughput unit has a discharge opening, and includes a vane which has an adjustable discharge angle with respect to the radial direction, and at least one flow guide wall. At least some of the fluid throughput units include an extension member downstream of the discharge opening, a flow guide profile on the extension member, and a baffle downstream of the flow guide profile. Connecting pins join the fluid throughput units to the supporting assembly, for adjustment of the vane discharge angle within a predetermined range.

Abstract: An aiming device for a firearm comprising a laying device adapted to be fitted on the firearm parallel thereto, a laser device and a power supply. The laying device has a double articulation on which the front part of the laser device is mounted, and an adjusting facility having an articulation and a vertical rod, the bottom part of the laser device being retained on the facility for movement in two directions, so that vertical and lateral drift can be adjusted for by means of two adjusting mechanisms.The power supply comprising at least one battery is for energising the laser device and is disposed therein or outside it.

Abstract: Effluent to be biologically purified is poured serially through three interconnected tanks with the first two tanks acting as activation tanks and the last tank acting as a post-clarification tank. After the concentration of activated sludge in the first tank has dropped to a predetermined value, the flow through the tanks is reversed so that the last tank, previously the post clarification tank, acts as one of the activation tank and the first tank, previously one of the activation tank, acts as the post clarification tank, while the middle tank continues to operate as the other of the activation tanks.In one embodiment, an aerator is provided in each tank and the aerators in the first and last tanks are switched on or off depending upon the direction of flow of effluent. In another embodiment, two movable aerators are provided and are disposed in use, in those tanks which are acting for the time being as activation tanks.