Spray device and spray nozzle unit

A spray device has a spray nozzle unit (1), wherein said spray nozzle unit (1) comprises a cavity (5) with an inlet (2) for receiving a pressurized liquid at an operating pressure and an outlet (3) for releasing a liquid spray during operation. A spray nozzle body (10) is fitted sealingly within said cavity (5), having a perforated nozzle layer (14) with at least one spray orifice (16) that extends between an upstream surface and a down stream surface thereof releasing at least one jet of said liquid spray at said downstream surface of said nozzle layer. The spray nozzle unit (1) is provided with a pressure safety device (30) upstream of said spray nozzle body (10). Said pressure safety device (30) comprises a closed burst layer (34) that closes a fluid pathway between said inlet (2) and said spray nozzle body (10) but ruptures once a threshold pressure is exceeded. Said operating pressure exceeds said threshold pressure.