A nozzle assembly, configured to receive fluid at pressures of greater than 1 bar. The nozzle assembly comprises a first perforate element (1) comprising one or more orifices (2), each orifice having an inlet and an outlet and a diameter of no more than 100 μm, and at least one second perforate element (4) further comprising a plurality of orifices of a smaller size than the one or more orifices of the first perforate element (1) and having a larger number of orifices than the first perforate element (1). The second perforate element (4) is configured to act as a filter and the second perforate element (4) is attached to the first perforate element (1). A perpendicular distance between the first and second perforate elements (4) is less than the diameter of the largest orifice of the first perforate element (1).