US4427712A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrodynamic coating process
Assignee: Continental Can Co Inc
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Filing: 1979-08-27
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Granted: 1984-01-24
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Expires: 1999-08-27
Abstract
Abstract A system and process for electrodynamic powder coating of conducting and non-conducting substrates using an electrodynamic fluidized bed. The system generally includes a coating applicator means for applying charged particles to the substrate to be coated, and postcharging means for applying to the substrate an additional charge of such polarity as to cause an increase in the electrostatic forces holding the coating particles to the substrate. The system further includes a precharging means for precharging the substrate with a charge of such polarity as to effect more uniform coating of the substrate and a higher rate of coating. Where the substrate to be coated is a continuous web, the system includes a conveying means for conveying the web through the various positions adjacent to the three aforementioned means. The coating applicator means may be an electrodynamic coating apparatus of the electrodynamic fluidized bed type and comprising a fluidized bed means and a charging bed means with a porous wall positioned therebetween, and a recharging means.
Inventors
- 👤 Peter N. Y. Pan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:55
CPC Classifications
B; B05; B05C; B05C19/00; B05C19/02; B05C19/025
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
94 words
An electrodynamic coating process comprising the steps of: (a) providing a substrate to be coated; (b) supplying charged particles of a given polarity charge in the vicinity of said substrate and thereby effecting coating of said substrate by said charged particles; and (c) applying in the vicinity of the coated side of said coated substrate and at a time when the supplying step (b) has been completed a postcharge of a polarity the same as said given polarity so as to effect an increase in the electrostatic forces holding said particles to said substrate.
Claim 2
Dependent Claim
94 words
An electrodynamic coating process comprising the steps of: (a) providing a substrate to be coated; (b) supplying charged particles of a given polarity charge in the vicinity of said substrate and thereby effecting coating of said substrate by said charged particles; and (c) applying in the vicinity of the coated side of said coated substrate and at a time when the supplying step (b) has been completed a postcharge of a polarity the same as said given polarity so as to effect an increase in the electrostatic forces holding said particles to said substrate.
Claim 3
Dependent Claim
45 words
A process as recited in claim 1 wherein said substrate provided in step (a) is a continuous web and step (a) includes conveying said substrate along a predetermined path which includes at least a coating position and a post-charging position both independent of one another.
Claim 4
Dependent Claim
37 words
A process as recited in claim 1 including after step (a) precharging the substrate with a polarity opposite to said given polarity so as to effect a higher deposition rate and more uniform coating during step (b).
Claim 5
Dependent Claim
46 words
A process as recited in claim 3 wherein said substrate provided in step (a) is a continuous web and step (a) includes conveying said substrate along a predetermined path which includes a precharging position, a coating position, and a postcharging position all independent of each other.
Claim 6
Dependent Claim
25 words
A process as recited in claim 1 wherein said postcharging includes the step of providing a groundplane electrode on the uncoated side of the web.
Claim 7
Dependent Claim
181 words
A process as recited in claim 1 wherein step (b) takes place with said substrate in a coating position by providing at said coating position: a fluidizing reservoir means for receiving said particles and for fluidizing said particles so as to provide fluidized particles for coating; charging bed means disposed adjacent to said fluidizing reservoir means for receiving said fluidized particles provided for coating, and disposed adjacent to said coating position for charging said fluidized particles so as to cause electrostatic attraction of said fluidized particles to said substrate; recharging means disposed between said charging bed means and said coating position for recharging said fluidized particles attracted to said substrate prior to coating of said substrate; and porous wall means between said fluidizing reservoir means and said charging bed means for containing said fluidized particles within said fluidizing reservoir means, and for providing passage of said fluidized particles from said fluidizing reservoir means and to said charging bed means, whereby said particles may be fed at a high feed rate without harmful effect on the operation of said charging bed means.
Claim 8
Dependent Claim
51 words
A process as recited in claim 6 wherein the providing of said recharging means includes providing a control grid located in such a position relative to said coating position that the particle-to-air ratio of said position of said control grid is 6-10 times lower than the bulk density of fed particles.
Claim 9
Dependent Claim
40 words
A process as recited in claim 6 wherein the providing of said charging bed means includes providing a charging plate and an array of corona pins mounted thereon, and the providing of said recharging means includes providing a control grid.
Claim 10
Dependent Claim
59 words
A process as recited in claim 6 wherein the providing of said charging bed means further includes providing first source means connected to said array of corona pins for providing a plate-pin voltage thereto, and the providing of said recharging means further includes providing second source means connected to said control grid for providing a control grid voltage thereto.
Claim 11
Dependent Claim
50 words
A process as recited in claim 9 wherein the providing of said first and second source means includes providing variable voltage sources adjustable to provide such values of said plate-pin voltage and control grid voltage, respectively, that said control grid voltage is lower in absolute value than said plate-pin voltage.
Claim 12
Dependent Claim
61 words
A process as recited in claim 9 wherein the providing of said first and second source means includes providing variable voltage sources adjustable to provide such levels and polarities of said plate-pin voltage and said control grid voltage, respectively, that said fluidized particles attracted to said substrate form a particle cloud statically suspended between said charging plate and said control grid.
Claim 13
Dependent Claim
59 words
A process as recited in claim 6 wherein the providing of said recharging means includes providing a control grid which has a geometrical design so as to cause said fluidized particles attracted to said substrate to form a particle cloud which is intensified according to said geometrical design, and said substrate is coated with varying intensities in various areas.
Claim 14
Dependent Claim
47 words
A process as recited in claim 6 wherein the providing of said recharging means includes providing further means for introducing ionized gas at a position relative to said coating position such that the particle-to-air ratio at said position is lower than the bulk density of fed particles.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-23 | 1987-07-25 | 1988-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-23 | 1991-07-25 | 1992-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-23 | 1995-07-25 | 1996-01-24 | $7700.00 | Window Closed / Lapsed |