In-flow evaporator

An evaporator for continuously evaporating a flowing liquid, comprising: - an outer casing; - an inner casing; - an EM wave generator; - a liquid supply; - a gas collector; and - a fluid barrier, impenetrable for fluids and penetrable for EM waves, dividing the evaporator in an EM inlet portion which includes an EM wave inlet and a fluid portion which includes a liquid inlet and a gas outlet, wherein in use: - a flow path of the EM inlet portion comprises a gaseous medium, - a flow path of the fluid portion comprises a running flow of fluid, and - the wave inlet allows EM waves to be introduced in the flow path of the EM inlet portion, through the fluid barrier, and ultimately in the flow path of the fluid portion, in which fluid portion the EM waves evaporate the liquid in said flow path.