Nozzles for Coating Applications
Engineering Consideration - Spray Angle
Generally the substance being sprayed to form a coat will have an intrinsic value. As such, only the target object should be sprayed otherwise money is being sprayed away. Getting the correct area coated, and only the correct area, is largely a matter of trigonometry.
The cone or triangle of spray is only maintained for a certain distance after which it breaks up. This coherence of the spray cone, be it hollow cone, flat fan or full cone, will depend upon the pressure and flow rate of the fluid. As the flow rates and pressures involved in most coating applications are relatively small it is important to check that the spray pattern will be maintained at the required distance. If pattern degradation is a problem for the desired distance and flow rate then air atomising nozzles may offer a solution as these low flow rate nozzles use compressed air to project a very fine spray some distance from the nozzle.
When utlising a series flat fan nozzles in a spray bar that is coating product on a conveyor then one needs to account for the slight tapering of each individual spray pattern. In order to achieve a uniform line of spray the individual flat fan patterns will need to be slightly overlapped as illustrated below.
