US3724416A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic resin powder spray system having improved powder dispensing means
Assignee: Allis Chalmers Corp
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Filing: 1970-05-28
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Granted: 1973-04-03
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Expires: 1990-05-28
Abstract
Abstract An electrostatic spray system for resin coating metallic articles heated above the melting temperature of the resin and moved on a conveyor through a spray booth past spray nozzles for resin powder includes means for recovering and recirculating the overspray resin particles which do not come into contact with the heated article, a bin for the recovered resin powder containing a magnet and a vibrating screen for cleaning the power, a supply hopper below the recovered power bin having venturis at its lower end operated by a pressurized air source for controlling the supply of powder to the spray nozzles, means driven by a motor for delivering new powder to the supply hopper, and means for detecting the level of new and recirculated powder in the supply hopper and for energizing the motor only when the powder in the supply hopper is below a predetermined amount which will prevent agglomeration and compacting of the resin powder particles. In one embodiment a hopper for new resin powder is disposed above the supply hopper, a rotatable valve at the lower end of the new powder hopper is rotated by an electric motor and controls the amount of new powder delivered to the supply hopper, and the powder level detecting means controls the energization of the electric motor. In an alternative embodiment, a flexible screw conveyor driven by an electric motor controlled by the powder level detecting means delivers the new powder to the bin containing the magnet and vibrating screen to remove agglomerated particles and ferromagnetic particles from the new powder.
Inventors
- 👤 H Diamond
- 👤 F Gustine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:18
CPC Classifications
B; B05; B05B; B05B7/00; B05B7/14; B05B7/1404; B05B7/144; B05B12/00; B05B12/08; B05B12/081; B05B14/00; B05B14/40; B05B14/48; B05B5/00; B05B5/16; B05B5/1683; B05B7/1445; B05B7/1477
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
50 words
In a system in accordance with claim 1 wherein said means for recovering includes a vibratory screen for removing coarse resin particles and said means for recovering delivers said recovered powder above said vibratory screen and said means for feeding new powder also delivers new powder above said vibratory screen.
Claim 2
Dependent Claim
41 words
In a system in accordance with claim 2 wherein said means for feeding new resin powder includes an electric motor and said level detecting means completes an energizing circuit to said motor to feed new resin powder to said supply hopper.
Claim 3
Dependent Claim
27 words
In a system in accordance with claim 3 wherein the walls of said supply hopper are flexible and including means for vibrating a wall of said hopper.
Claim 4
Dependent Claim
32 words
In a system in accordance with claim 3 wherein said means for feeding new powder includes a flexible conduit and a screw conveyor within said flexible conduit driven by said electric motor.
Claim 5
Dependent Claim
61 words
In a system in accordance with claim 5 wherein said level detecting means includes a vibrating rod probe depending to a predetermined level within said supply hopper, exciting electric coil means for driving said probe into self-sustained oscillations when said probe is uncovered, and pickup electric coil means for generating an output signal in response to oscillations of said rod probe.
Claim 6
Dependent Claim
62 words
In a system in accordance with claim 5 wherein said means for supplying resin powder to said electrostatic spray nozzle includes a venturi communicating with the lower end of said supply hopper, a conduit between said electrostatic spray nozzle and said venturi, and pressurized air supply means communicating with said venturi for propelling said powder through said conduit and said spray nozzle.
Claim 7
Dependent Claim
32 words
In an electrostatic powder coating system in accordance with claim 2 wherein said means for recovering includes continuously operating powder separator means which discharges recirculated powder collected therein above said vibratory screen.
Claim 8
Dependent Claim
57 words
In a system in accordance with claim 1 wherein said level detecting means includes a vibratory rod probe depending within said supply hopper, exciting electric coil means for driving said probe into self-sustained oscillations when said probe is uncovered, and pickup electric coil means for generating an output signal in response to oscillations of said rod probe.
Claim 9
Dependent Claim
53 words
In a system in accordance with claim 1 wherein said means for supplying new resin powder to said supply hopper is driven by a variable speed motor and also includes means for varying the speed of said motor as a function of the amount of new and recirculated powder in said supply hopper.
Claim 10
Dependent Claim
88 words
In a system in accordance with claim 1 wherein said means for supplying resin powder to said nozzle includes a venturi having a housing at the lower end of said supply hopper provided with a chamber registering with said supply hOpper into which said resin powder in said supply hopper may fall, a conduit between said spray nozzle and said venturi housing in communication with said chamber, and pressurized air supply means for forcing said power out of said chamber and through said conduit and said spray nozzle.
Claim 11
Dependent Claim
57 words
In a system in accordance with claim 1 wherein said means for feeding new powder includes a flexible conduit, a screw conveyor within said flexible conduit, and an electric motor for driving said screw conveyor, and wherein said level detecting means competes an energizing circuit to said motor to feed new resin powder to said supply hopper.
Claim 12
Dependent Claim
83 words
In a system in accordance with claim 12 wherein said means for recovering includes a vibratory screen above said supply hopper, said screw conveyor discharges new powder above said vibratory screen, and said means for supplying resin powder to said electrostatic spray nozzle includes a venturi communicating with the lower end of said supply hopper, a conduit between said venturi and said nozzle, and pressurized air supply means communicating with said venturi for moving powder through said conduit and out of said nozzle.
Claim 13
Dependent Claim
30 words
In an electrostatic powder coating system in accordance with claim 1 wherein said means for recovering resin powder particles includes continuously operating powder collector means communicating with said supply hopper.
Claim 14
Dependent Claim
157 words
In an electrostatic resin powder system for coating a metallic article, in combination, an electrostatic resin powder spray nozzle, means for electrostatically charging resin powder particles ejected from said nozzle, means for maintaining said article at a potential which will attract said charged resin powder particles to it, a supply hopper for new and recirculated resin powder, means communicating with said supply hopper for supplying resin powder to said nozzle, means for recovering resin particles from said spray nozzle which do not contact said metallic article and for delivering them to said supply hopper, a supply bin for new resin powder, valve means between said bin and said supply hopper for controlling the amount of new resin powder delivered from said bin to said supply hopper, and level detecting means in said supply hopper for actuating said valve means when the amount of new and recovered resin powder in said supply hopper is below a predetermined magnitude.
Claim 15
Dependent Claim
150 words
In an electrostatic resin powder system for coating a metallic article, in combination, an electrostatic resin powder spray nozzle, means for electrostatically charging resin powder particles ejected from said nozzle, a supply hopper for new and recirculated resin powder, means communicating with said supply hopper for supplying resin powder to said nozzle, a bin for recirculated powder disposed above said supply hopper, means for recovering resin particles from said spray nozzle which do not contact said metal article and for delivering them to said bin for recirculated powder, a supply bin for new resin powder, valve means between said new powder bin and said supply hopper for controlling the amount of new resin powder delivered to said supply hopper, and level detecting means in said supply hopper for actuating said valve means when the amount of new and recirculated resin powder in said supply means is below a predetermined magnitude.
Claim 16
Dependent Claim
77 words
In a system in accordance with claim 16 and including a magnet and a vibratory screen in said bin for recirculated powder and wherein said means for recovering delivers said recovered powder particles above said magnet and said screen and said valve means includes a rotatable cylinder having elongated powder receiving depressions in its outer periphery parallel to its axis and an electric motor for rotating said cylinder and wherein said level detecting means controls said motor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |