A spraying apparatus for spraying liquid surface treatment material which
includes a gas inlet, a liquid inlet and an outlet nozzle. The apparatus
also has a needle valve for regulating the supply of surface treatment
material to the nozzle. The needle valve is at least partially located
within a gas outlet chamber and is adapted so as to cause minimal
disruption to the gas flow from the gas inlet to the nozzle. To further
aid gas flow efficiency, the gas supply passage is substantially
straight, the outlet chamber has a laterally outwardly tapering inlet and
an inwardly tapering outlet and a smooth radius of curvature from the gas
supply passage into the outlet chamber. There is also provided a control
means for controlling the axial movement of the needle valve, the control
means being provided with indicator means so as to provide an accurate,
repeatable control means.