Abstract: A rotor apparatus for extracting energy from bidirectional fluid flows comprises a first rotor (7) mounted for rotation about an axis of rotation (4) in a first direction of rotation, the first rotor (7) having at least one helical blade (2) with a pitch that decreases in a direction along the axis of rotation (4); and a second rotor (8) mounted for rotation about the same axis of rotation (4) in an opposite direction of rotation and having at least one helical blade (2) with a pitch that increases in the same direction along the axis of rotation (4), wherein fluid exiting the first rotor (7) is passed to the second rotor (8).

Abstract: An electrodialysis unit 8 for treating water, such as a treatment in order to kill microorganisms, comprises: a membrane cell, an anode flow path 52 for directing a portion of an incoming water flow to an anode side of the membrane cell, a cathode flow path 50 for directing a portion of an incoming water flow to a cathode side of the membrane cell, a temperature monitoring device 9a for monitoring the temperature of the water and a heater 9b for increasing the temperature of the water in the anode flow path 52 before it reaches the membrane cell, wherein the heater 9b is arranged to operate to increase the temperature of the water in the anode flow path 52 when the original water temperature is below a predetermined level. A membrane 71 is located between the electrodes (cathodes 68 and anode 70).

Abstract: A liquid or water treatment apparatus comprising one or both of an electrodialysis cell and a cavitation unit. The cavitation unit generates cavitation in the liquid by flow of the liquid into a constriction where cavitation bubbles are formed and then to an outlet where cavitation bubbles implode, and the constriction includes an aperture formed by walls which are long and narrowly spaced in a plane normal to the flow direction. The electrodialysis cell is arranged with an inlet flow path for directing only part of a quantity of water to be treated through the electrodialysis cell, and an outlet flow path for returning a product of the electrodialysis cell to the remainder of the water.

Abstract: A cleaning head for a filter backwashing mechanism, the cleaning head comprising: a nozzle for contact with a filter element wall 1 and for receiving a flow of backwash fluid 8, 9, wherein the nozzle comprises a rotor 3 for generating a torque when exposed to the flow of backwash fluid 8,9, and wherein the cleaning head is arranged such that at least a part of the nozzle will move toward and/or apply a force to the filter element wall 1 as a result of the torque generated by the rotor 3.

Abstract: A rotor apparatus for extracting energy from bidirectional fluid flows comprises a first rotor (7) mounted for rotation about an axis of rotation (4) in a first direction of rotation, the first rotor (7) having at least one helical blade (2) with a pitch that decreases in a direction along the axis of rotation (4); and a second rotor (8) mounted for rotation about the same axis of rotation (4) in an opposite direction of rotation and having at least one helical blade (2) with a pitch that increases in the same direction along the axis of rotation (4), wherein fluid exiting the first rotor (7) is passed to the second rotor (8).

Abstract: A liquid or water treatment apparatus comprising one or both of an electrodialysis cell and a cavitation unit. The cavitation unit generates cavitation in the liquid by flow of the liquid into a constriction where cavitation bubbles are formed and then to an outlet where cavitation bubbles implode, and the constriction includes an aperture formed by walls which are long and narrowly spaced in a plane normal to the flow direction. The electrodialysis cell is arranged with an inlet flow path for directing only part of a quantity of water to be treated through the electrodialysis cell, and an outlet flow path for returning a product of the electrodialysis cell to the remainder of the water.