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US 4,824,295 AGranted
Powder delivery system
AssigneeNordson Corporation
InventorJohn Sharpless
Life of this patent
Estimating the term…
Abstract
A method and apparatus for pumping a steady flow of powder from a powder spray gun of a powder spray system by pumping the powder from a fluidized bed feed hopper to the spray gun via a small auxiliary fluidized bed hopper located in close proximity to the powder spray gun. The apparatus comprises a primary fluidized bed hopper into which reclaimed powder is supplied from a powder spray booth via a powder filter module and a sieve. Powder from the primary feed hopper is pumped to the gun via an auxiliary and much smaller capacity auxiliary fluidized bed hopper located in relative close proximity to the spray gun.
Claims6
In combination, a powder spray booth, a powder spray gun for spraying solid particulate powder onto workpieces contained within said booth;
- a filter module for collecting oversprayed powder from said booth, and a sieve for receiving powder from said filter module and separating said oversprayed powder from coarser particles,
- a primary fluidized bed hopper for receiving powder from said sieve, said primary hopper having an interior chamber adapted to receive and fluidize powder material,
- a primary pneumatic powder pump having an inlet port and a discharge port, said primary powder pump having a low pressure venturi pumping chamber contained therein and a powder flow passage intersecting said venturi pumping chamber, said powder flow passage having an inlet connected via a siphon tube to said interior chamber of said primary hopper,
- means connecting said inlet port of said primary powder pump to a source of high pressure air,
- an auxiliary fluidized bed hopper having an interior chamber of substantially less capacity than said interior chamber of said primary hopper, said auxiliary fluidized bed hopper being located in close proximity to said powder spray booth,
- first conduit means connecting said outlet port of said primary powder pump to said interior chamber of said auxiliary hopper,
- at least one auxiliary pneumatic powder pump having an inlet port and a discharge port, said auxiliary powder pump having a low pressure venturi pumping chamber contained therein and a powder flow passage intersecting said venturi pumping chamber, said powder flow passage of said auxiliary powder pump having an inlet connected via a siphon tube to said interior chamber of said auxiliary hopper,
- second conduit means connecting said outlet port of said auxiliary powder pump to said powder spray gun, said second conduit means being substantially shorter than said first conduit means, and
- means for maintaining a constant level of fluidized powder in said auxiliary hopper, said means for maintaining a constant level of fluidized powder in said auxiliary hopper comprising an overflow tube extending between said auxiliary hopper and said primary hopper, said overflow tube having an inlet spaced upwardly from the bottom of said interior chamber of said auxiliary hopper.
6 more elements
In combination, a powder spray booth, a powder spray gun for spraying solid particulate powder onto workpieces contained within said booth;
- a filter module for collecting oversprayed powder from said booth, and a sieve for receiving oversprayed powder from said filter module and separating said oversprayed powder from coarser particles,
- apparatus for dispensing a relatively constant flow of solid particulate powder from said powder spray gun, which apparatus comprises,
- means including a relatively large capacity primary hopper for receiving powder from said sieve and for fluidizing said solid particulate powder,
- a substantially smaller capacity auxiliary hopper,
- means including a relatively long conduit for supplying said powder from said primary hopper into said auxiliary hopper,
- means for fluidizing said powder in said auxiliary hopper,
- means including a relatively short conduit for supplying said solid particulate material from said auxiliary hopper to said powder spray gun,
- said means for supplying said powder from said primary hopper to said auxiliary hopper being operable to supply a greater quantity of solid particulate powder material to said auxiliary hopper than is supplied from said auxiliary hopper to said spray gun, and
- means for transporting excess powder from said auxiliary hopper to said primary hopper so as to maintain a substantially constant level of fluidized powder in sad auxiliary hopper.
6 more elements
In combination, a powder spray booth, a powder spray gun for spraying solid particulate powder onto workpieces contained within said booth;
- a filter module for collecting oversprayed powder from said booth,
- a primary fluidized bed hopper for receiving powder from said filter module, said primary hopper having an interior chamber adapted to receive and fluidize powder material,
- a primary pneumatic powder pump having an inlet port and a discharge port, said primary powder pump having a low pressure venturi pumping chamber contained therein and a powder flow passage intersecting said venturi pumping chamber, said powder flow passage having an inlet connected to said interior chamber of said primary hopper,
- means connecting said inlet port of said primary powder pump to a source of high pressure air,
- an auxiliary fluidized bed hopper having an interior chamber of substantially less capacity than said interior chamber of said primary hopper,
- first conduit means connecting said outlet port of said primary powder pump to said interior chamber of said auxiliary hopper,
- at least one auxiliary pneumatic powder pump having an inlet port and a discharge port, said auxiliary powder pump having a low pressure venturi pumping chamber contained therein and a powder flow passage intersecting said venturi pumping chamber, said powder flow passage of said auxiliary powder pump having an inlet connected to said interior chamber of said auxiliary hopper,
- second conduit means connecting said outlet port of said auxiliary powder pump to said powder spray gun, said second conduit means being substantially shorter than said first conduit means, and
- means for maintaining a constant level of fluidized powder in said auxiliary hopper, said means for maintaining a constant level of fluidized powder in said auxiliary hopper comprising an overflow tube extending between said auxiliary hopper and said primary hopper, said overflow tube having an inlet spaced upwardly from the bottom of said interior chamber of said auxiliary hopper.
6 more elements
In combination, a powder spray booth, a powder spray gun for spraying solid particulate powder onto workpieces contained within said booth;
- a filter module for collecting oversprayed powder from said booth,
- apparatus for dispensing a relatively constant flow of solid particulate powder from said powder spray gun, which apparatus comprises,
- means including a relatively large capacity primary hopper for receiving powder from said filter module and for fluidizing said solid particulate powder,
- a substantially smaller capacity auxiliary hopper,
- means including a pump and a relatively long conduit for supplying said powder from said primary hopper into said auxiliary hopper,
- means for fluidizing said powder in said auxiliary hopper,
- means including a pump and a relatively short conduit for supplying said solid particulate material from said auxiliary hopper to said powder spray gun,
- said means for supplying said powder from said primary hopper to said auxiliary hopper being operable to supply a greater quantity of solid particulate powder material to said auxiliary hopper than is supplied from said auxiliary hopper to said spray gun, and
- means for transporting excess powder from said auxiliary hopper to said primary hopper so as to maintain a substantially constant level of fluidized powder in said auxiliary hopper.
6 more elements
Dependencies are inferred from the claim text.