PROCESS AND APPARATUS FOR COATING OBJECTS WITH POWDERY SUBSTANCES

• US 3,709,434 A
• Filed: 04/21/1971
• Issued: 01/09/1973
• Est. Priority Date: 04/24/1970
• Status: Expired due to Term

• Current Assignee: Fred Luderer, Karl-Heinz Stahlschmidt, Otto Gebhardt
• Original Assignee: Fred Luderer, Karl-Heinz Stahlschmidt, Otto Gebhardt
• Inventors: Gebhardt, Otto, Luderer, Fred, Stahlschmidt, Karl-Heinz
• Primary Examiner(s): Wood, Jr., M. Henson
• Assistant Examiner(s): Grant, Edwin D.
• Application Number:
  US05/135,868
• Time in Patent Office: 629 Days
• Field of Search: 239/8,427,427.3,428,429,430,431,433,589 117/16 302/53
• US Class Current: 239/8
• CPC Class Codes: B05B 5/032 for spraying particulate materials
• CPC Class Codes: B05B 5/1691 Apparatus to be carried on or by a person or with a container fixed to the discharge device

Abstract

A powder spraying apparatus comprises a finishing container and a spraying system attached thereto. The spraying system comprises a nozzle portion and a connector portion which communicates the nozzle with the finishing container. The finishing container and the connector portion each have an independently controlled supply of compressed air for keeping powder particles in a fluidized, or suspended, state to prevent the particles from lumping together. The nozzle is operated by an additional supply of compressed air which creates a suction force in a manner allowing the nozzle to aspirate powder from the finishing container. By switching off the supply of compressed air to the connector portion just prior to switching off the nozzle air, the powder within the connector portion will lump, thus preventing an undesirable discharge through the nozzle under the influence of residual pressure in the finishing container. An attachment is provided for the nozzle which serves to change the shape of fluid flow therefrom and which has air flow means for preventing the particles from lumping up therein.

Claims

1. A process for coating objects with powdery substances, the process utilizing:

a finishing container;

at least one compressed air operated spraying system, including a powder diffusing means, being connected to and communicating with the finishing container;

first means for creating a bed of turbulence within the finishing container;

means for creating a bed of turbulence within the spraying system adjacent the diffusing means; and

third means, cooperable with said diffusing means, for creating an aspirating force to aspirate powder particles from the finishing container through the diffusing means;

the process comprising;

creating a first bed of turbulence in the finishing container to place powder particles contained therein in a fluidized state;

creating a second bed of turbulence within the spraying system adjacent the diffusing means to place powder particles located thereat in a fluidized state; and

aspirating powder particles from the finishing container through the diffusing means while maintaining the particles in a fluidized state.

2. The process of claim 1 further utilizing:

a plurality of spraying systems connected to the finishing container; and

means for independently controlling the flow output of each spraying system;

the process further including the step of;

independently controlling the flow output of each spraying system.

3. Apparatus for coating objects with powdery substances and comprising:

a finishing container;

at least one compressed air operated spraying system, including a powder diffusing means, being connected to and communicating with the finishing container;

first means for creating a bed of turbulence within the finishing container to place powder particles located therein in a fluidized state;

second means for creating a bed of turbulence within the spraying system adjacent the diffusing means to place powder particles located thereat in a fluidized state; and

third means, cooperable with the diffusing means, for creating an aspirating force to aspirate powder particles from the finishing container through the diffusing means;

the beds of turbulence in the diffusing means and in the spraying system being operable to maintain the particles in a fluidized state during movement of the particles to the diffusing means.

4. Apparatus according to claim 3 wherein the finishing container comprises:

a generally upright cylinder, on the outer surface of which is mounted at least one spraying system; and

the cylinder having a feed connection at its upper end adapted for communication with a powder supply container;

the lower end of the cylinder being defined by a bottom plate in which is provided an opening adapted to receive compressed air.

5. Apparatus according to claim 4 wherein the cylinder further includes:

a wall of porous material spaced from the bottom plate and defining therewith an air chamber;

the opening being positioned at the lower end of the chamber.

6. Apparatus according to claim 3 wherein the finishing container comprises:

a generally upright cylinder formed of inner and outer spaced-apart walls defining an air chamber therebetween;

the inner wall being formed of a porous material;

the outer wall being connected to means adapted to supply compressed air into the air chamber.

7. Apparatus according to claim 4 wherein the feed connection includes a continuous bore to provide ventilation for the cylinder.

8. Apparatus according to claim 4 wherein the feed connection includes a conduit extending downwardly into the cylinder interior.

9. Apparatus according to claim 4 further including:

regulating means for automatically controlling the amount of powder within the cylinder.

10. Apparatus according to claim 4 wherein the cylinder further includes:

a plurality of openings, each being adapted for communication with a spraying system; and

a cover detachably positioned over each opening being in non-communication with a spraying system.

11. Apparatus according to claim 10 wherein the spraying system is swivelly mounted on the cylinder to permit the spraying system to rotate about its longitudinal axis with respect to the cylinder.

12. Apparatus according to claim 11 wherein the spraying system includes a universal swivel connection permitting the diffusing means to pivot with respect to the cylinder.

13. Apparatus according to claim 12 wherein the spraying system further includes:

a supporting foot having a channel communicating with the diffusing means; and

a porous pipe member being positioned within inner walls of the channel and spaced therefrom to define an air chamber;

the chamber being connected to a source of compressed air.

14. Apparatus according to claim 4 wherein the cylinder is swivelly mounted so as to be pivotal from an upright position to an angled position.

15. Apparatus according to claim 4 and further including an additional finishing container positioned opposite the first-mentioned finishing container;

a powder supply container mounted above the finishing containers; and

powder guide means connected between the supply container and each finishing container.

16. Apparatus according to claim 4 wherein the diffusing means includes:

a longitudinally extending diffuser member;

a generally bell-shaped body positioned on the outer end of the diffuser member and having at least one opening therein; and

a supply line being connected between the opening and a source of compressed air.

17. Apparatus according to claim 16 wherein:

the bell-shaped body has an inside wall spaced from the outer end of the diffuser member to define the opening.

18. Apparatus according to claim 16 and further including:

a plurality of bores being formed in the bell-shaped body and being directed inwardly of the bell-shaped body; and

feed channel means being connected to the bores and connected to a source of compressed air.

19. Apparatus according to claim 4 wherein the first and second means for creating a bed of turbulent flow in the finishing container and spraying system, respectively, and the means for creating an aspirating force each includes an independently controlled flow of compressed air.

20. Apparatus according to claim 4 and further including:

a powder supply container, and a guiding conduit extending between the powder supply container and the finishing container.

21. In a spraying apparatus having a longitudinally extending diffuser member, the combination therewith of a spray attachment comprising:

a generally bell-shaped body positioned on the outer end of the diffuser member;

the generally bell-shaped body having an inner wall spaced from the diffuser means to define therewith an annular gap; and

a supply line being connected between the annular gap and a source of compressed air.

22. A method of preventing ejection of powder particles from a powder spraying system, the method utilizing:

a longitudinally extending diffuser member;

first means cooperating with the diffuser member for creating an aspirating force therein and adapted to draw powder particles through the diffuser member from a powder source positioned away from the diffuser member;

a channel-forming member connected to the diffuser member and adapted to communicate the diffuser member with the powder source; and

second means for optionally creating a bed of turbulence within the channel forming member to prevent powder particles located therein from lumping together;

the method comprising;

rendering the second means incapable of creating a bed of turbulence juSt prior to rendering the first means incapable of creating an aspirating force, to cause the powder particles located in the channel forming member to lump together for preventing a flow of powder to the diffuser member.

23. A powder spraying system comprising:

a longitudinally extending diffuser member;

first means cooperable with the diffuser member for creating an aspirating force therein and adapted to draw powder particles through the diffuser member from a remotely-positioned powder source;

a channel-forming member connected to the diffuser member and adapted to communicate the diffuser member with the powder source;

second means, including a foraminous pipe positioned in the channel-forming member, for optionally creating a bed of turbulence within the channel-forming member to prevent powder particles located therein from lumping together; and

means for rendering the second means inoperable prior to rendering the first means inoperable, for permitting the powder particles located within the channel-forming member to lump together to close-off communication with the diffuser member.