Abstract: A method for spraying a powdered to granular bulk material is disclosed in which a stream of propellant gas is mixed with the bulk material and the mixture is sprayed by a suitable known spraying device. Unwanted clogging of conduits and wastage of the bulk material are prevented by rerouting the flow of the bulk-material/gas mixture at a point upstream from the spray device whenever it is desired to interrupt spraying. A device for effecting this method is also disclosed.

Abstract: A method and apparatus are disclosed for spray coating one or a series of objects with at least two powder coating materials in succession or alternately. When a change of the material being sprayed is to be effected, the flow of the first material is terminated, preferably by means of a squeeze valve, the flow path of the first material is flushed with a fluid, preferably air, and the second spray material is sprayed. The relative positions of the apparatus forming the respective flow paths of the two spray materials are not changed during this process. In one preferred embodiment, feed conduits corresponding to respective spray materials converge into a single delivery conduit. Each feed conduit includes means for closing and opening it. Means are provided for flushing at least part of a given feed conduit, or the delivery conduit, or both, with a fluid. The flushing can preferably be done pulsatingly.

Abstract: A pneumatic conveyor for powdered to granular bulk material, having adjustable conveyance capacity, is disclosed, the capacity being adjusted by electromagnetic adjustment of a pressure regulator disposed in a conduit used to supply a propellant for drawing the bulk material from a storage container thereof and for conveying it. A supplemental supply of gas, which may be but need not be different from the propellant gas, may be provided to control the flow of propellant gas independently of the first pressure regulator. In this case, the flow of the supplemental gas may itself be controlled by a second pressure regulator. The pressure regulators operate according to the diffuser or Venturi principle. The device may be particularly advantageously applied to the spray-coating of articles with a bulk material.

Abstract: The disclosure concerns an atomizer head used for atomizing wet lacquer, or the like. The atomizer head has an air conduit communicating with an air outlet part and has a liquid conduit communicating with a liquid outlet part. The air outlet part is radially outside the liquid outlet part. There is an inner part of the atomizer head which adjoins the outlet end of the liquid conduit. The inner part has an outside which is preferably trumpet shaped. The liquid conduit outlet end communicates with the outside of the inner part through obliquely extending ducts. There is an intermediate part that is outside the outlet end of the liquid conduit and outside the inner part. A cap is positioned outside the intermediate part. The air conduit is in part defined between the intermediate part and the cap. The intermediate part has a peripheral flange which is engaged by the interior of the cap. The flange has grooves extending along it for passage of air. The flange is in the air conduit.