Abstract: An apparatus for entraining a powder in a process fluid is provided. The apparatus (2?) has a process passage (22) having a passage inlet (24) connectable to a source of process fluid, and a passage outlet (26). A nozzle (30) opens into the process passage (22) intermediate the passage inlet (24) and passage outlet (26). The nozzle (30) has a nozzle inlet (32), a nozzle outlet (36) and a nozzle throat (34) intermediate the nozzle inlet (32) and nozzle outlet (36), where the nozzle throat (34) has a cross sectional area which is less than that of the nozzle inlet (32) and nozzle outlet (36). At least one first port (42?) opens into the process passage (22) adjacent the nozzle outlet (36), and an entrainment fluid supply chamber (38) is in fluid communication with the nozzle 30. A first powder supply chamber (44?) is connected to the first port (42?) by a first powder supply passage (46), wherein the powder supply chamber (44?), powder supply passage (46) and first port (42?) are coaxial.