Water injection device for a by-pass steam system of a power plant

The water injection device (1) has a flow channel (2) that is provided with a steam inlet (8) and a steam outlet (10). An injection nozzle (12) is formed between steam inlet and steam outlet. The injection nozzle is arranged to hollow portion (14) spaced-apart from inner wall (6) of the flow channel. The chambers (16,18) are provided in hollow portion. A mixing element (24) is arranged at hollow portion.