Powder spray apparatus for the manufacture of coated fasteners

• US 5,571,323 A
• Filed: 03/27/1995
• Issued: 11/05/1996
• Est. Priority Date: 08/27/1993
• Status: Expired due to Fees

• Current Assignee: Nylok Corp. (Berkshire Hathaway Incorporated)
• Original Assignee: Nylok Corp. (Berkshire Hathaway Incorporated)
• Inventors: Sessa, Eugene, Duffy, Richard J.
• Primary Examiner(s): Housel, James C.
• Assistant Examiner(s): FREED, RACHEL
• Application Number:
  US08/410,944
• Time in Patent Office: 589 Days
• Field of Search: 118/308, 118/310, 118/326, 118/620, 118/500, 118/313
• US Class Current: 118/308
• CPC Class Codes: B05B 7/1404 Arrangements for supplying particulate material
• CPC Class Codes: B05B 7/1477 means for supplying to several spray apparatus
• CPC Class Codes: B05D 1/12 Applying particulate materials B05D1/06, B05D1/10 take precedence
• CPC Class Codes: B05D 2258/02 The objects being coated one after the other
• CPC Class Codes: B05D 2401/32 applied as powders
• CPC Class Codes: B05D 3/0218 Pretreatment, e.g. heating the substrate

Abstract

An apparatus for generating a powder stream to be applied to a work piece includes a powder reservoir, a mixing chamber, a powder metering valve, a transfer conduit, and a nozzle. The metering valve allows control of the powder flow from the reservoir into the mixing chamber where it is dispersed with and entrained in an air flow entering the chamber through an aspirating inlet. The air entrained powder is then conveyed from the mixing chamber via the transfer conduit to the nozzle. The nozzle includes a controllable gas flow input and a powder stream generating passageway configured and associated with the transfer conduit to generate a reduced pressure in the conduit and mixing chamber which draws the air borne powder from the chamber into the nozzle. One or more of the individual components are adjustable to control the size, configuration, thickness or other parameters of the coating on the work piece as a result of the applied powder stream.

Claims

1. An apparatus for dispensing powder and generating a powder stream comprising:

a powder reservoir having means for maintaining a substantially constant level of powder within the reservoir;

a mixing chamber;

a passageway extending between said mixing chamber and said reservoir and terminating in a powder inlet to said mixing chamber;

an adjustable powder metering valve, disposed in said powder inlet, for delivering a controlled amount of powder from said reservoir to said mixing chamber;

an aspirating air inlet, disposed in said mixing chamber separate from said powder inlet, for introducing and mixing air with powder in said mixing chamber;

an airborne powder outlet, disposed in said mixing chamber;

a nozzle including a powder stream generating passageway, said passageway having a controllable gas flow input and a separate airborne powder input;

a transfer conduit having one end in communication with an outlet of said mixing chamber and a second end communicating with the airborne powder input to said nozzle; and

said controllable gas flow input generating a gas flow within said nozzle passageway and a vacuum within said mixing chamber and said transfer conduit to convey powder to said nozzle;

whereby said substantially constant powder level, said powder metering valve, said aspirating air inlet and said controllable gas flow input are operatively associated to generate a substantially uniform powder stream flowrate.

2. The powder dispensing apparatus of claim 1 wherein said powder metering valve is a needle valve.

3. The powder dispensing apparatus of claim 1 wherein said aspirating air inlet is adjustable.

4. The powder dispensing apparatus of claim 1 wherein said controllable gas flow input is adjustable.

5. The powder dispensing apparatus of claim 1 wherein two or more of said powder metering valve, said aspirating air inlet and said controllable gas flow input are independently adjustable.

6. The powder dispensing apparatus of claim 1 wherein said powder metering valve includes an external handle for adjusting the flow of powder from said reservoir into said mixing chamber.

7. The powder dispensing apparatus of claim 1 wherein said powder is directed from said reservoir through said metering valve and into said mixing chamber by gravity and wherein a vibrator is operatively associated with said reservoir to facilitate said gravity flow.

8. The powder dispensing apparatus of claim 1 wherein said nozzle has a bore of substantially round, constant cross-sectional shape and area.

9. An apparatus for dispensing powder and generating a powder stream to be applied to a work piece comprising:

a powder reservoir having means for maintaining a substantially constant level of powder within the reservoir;

a mixing chamber;

a powder passageway extending between said mixing chamber and said reservoir and terminating in a powder inlet to said mixing chamber;

an adjustable powder metering valve, disposed in said powder inlet, for delivering a controlled amount of powder from said reservoir to said mixing chamber;

an adjustable aspirating air inlet, disposed in said mixing chamber separate from said powder inlet;

for introducing and mixing air with powder in said mixing chamber;

an airborne powder outlet, disposed in said mixing chamber;

a nozzle, adjacent to said work piece, including a powder stream generating passageway, said passageway having a controllable gas flow input and a separate airborne powder input;

a transfer conduit having one end in communication with an outlet of said mixing chamber and a second end communicating with the airborne powder input to said nozzle;

said controllable gas flow input generating a gas flow within said nozzle passageway and a vacuum within said mixing chamber and said transfer conduit to thereby generate a powder stream discharged from said nozzle passageway and directed toward said work piece; and

a vacuum collector positioned adjacent said work piece to receive over spray powder;

whereby said substantially constant powder level, said powder metering valve, said aspirating air inlet and said controllable gas flow input are operatively associated to generate a substantially uniform powder stream flowrate.

10. The powder dispensing apparatus of claim 9 wherein said powder metering valve is a needle valve.

11. The powder dispensing apparatus of claim 9 wherein said controllable gas flow input is adjustable.

12. The powder dispensing apparatus of claim 9 wherein said vacuum collector is adjustable to vary the reduced pressure at the inlet to said collector.

13. The powder dispensing apparatus of claim 9 wherein two or more of said powder metering valve, said aspirating air inlet, said controllable gas flow input and said vacuum collector are adjustable.

14. The powder dispensing apparatus of claim 9 wherein a plurality of powder metering valves, mixing chambers, transfer conduits, nozzles, and vacuum collectors are employed, and at least each of said nozzles is independently positionable relative to a path of travel of said work piece.

15. The powder dispensing apparatus of claim 14 wherein each of said plurality of nozzles is operatively associated with only one powder metering valve, mixing chamber, transfer conduit and vacuum collector.