US4802625A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic spray coating device for coating with powder
Assignee: Gema Switzerland GmbH
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Filing: 1987-03-06
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Granted: 1989-02-07
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Expires: 2007-03-06
Abstract
Abstract An electrostatic spray device for coating powder has a powder channel, the downstream end of which has a spray opening for the spraying of the coating powder. At least one gas channel with at least one gas outlet opening is arranged substantially in the radial center of the powder channel upstream of its spray opening, the gas outlet discharging axially in the direction toward the spray opening. At least one electrode, around which gas from the gas channel flows, is located in the gas outlet opening, the downstream electrode end of the electrode terminating substantially at the downstream end thereof. Within the powder channel, directly in front of its spray opening, a funnel-shaped powder channel section is provided for compacting the powder concentration. The gas stream injects electric charges into this section, which the stream of gas has taken up from the electrode. The spray opening preferably has the shape of a slot.
Inventors
- 👤 Karl Buschor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 00:34
CPC Classifications
B; B05; B05B; B05B5/00; B05B5/025; B05B5/03; B05B5/032
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
222 words
An electrostatic spray coating device for coating with powder, comprising: a powder channel defined by elongated channel wall means for receiving coating powder and discharging it at a spray opening at a downstream end thereof; at least one gas channel which has at least one gas outlet, the gas channel and its gas outlet being arranged substantially in the radial center of said powder channel upstream of its spray opening and discharging axially downstream toward said spray opening; and at least one electrode disposed for having gas from the gas channel flow around it, said electrode being located om the gas outlet and having a downstream electrode end terminating substantially at the downstream end of the gas outlet; the powder channel further having a generally conical section which becomes narrower substantially from the gas outlet to the spray opening in the downstream direction, said conical section including means forming a damming region for compacting the coating powder and for simultaneously electrostatically charging the powder before it is discharged, and into which the gas outlet debouches; the downstream ends of said gas outlet and said electrode end being located within said damming region in said conical section; the radial center of the spray opening being located substantially at the point of the smallest diameter of the conical section and opposite the gas outlet.
Claim 2
Dependent Claim
222 words
An electrostatic spray coating device for coating with powder, comprising: a powder channel defined by elongated channel wall means for receiving coating powder and discharging it at a spray opening at a downstream end thereof; at least one gas channel which has at least one gas outlet, the gas channel and its gas outlet being arranged substantially in the radial center of said powder channel upstream of its spray opening and discharging axially downstream toward said spray opening; and at least one electrode disposed for having gas from the gas channel flow around it, said electrode being located om the gas outlet and having a downstream electrode end terminating substantially at the downstream end of the gas outlet; the powder channel further having a generally conical section which becomes narrower substantially from the gas outlet to the spray opening in the downstream direction, said conical section including means forming a damming region for compacting the coating powder and for simultaneously electrostatically charging the powder before it is discharged, and into which the gas outlet debouches; the downstream ends of said gas outlet and said electrode end being located within said damming region in said conical section; the radial center of the spray opening being located substantially at the point of the smallest diameter of the conical section and opposite the gas outlet.
Claim 3
Dependent Claim
25 words
A spray device according to claim 1, further comprising coatable powder particles which form a compacted and electrostatically charged powder mass in said damming region.
Claim 4
Dependent Claim
28 words
A spray device according to claim 2, wherein an angle defined by conical surfaces of the conical section of the powder channel is substantially between 100° and 140°.
Claim 5
Dependent Claim
13 words
A spray device according to claim 3, wherein the angle is substantially 120°.
Claim 6
Dependent Claim
34 words
A spray device according to claim 3, wherein a distance from the downstream end of the gas outlet to the downstream end of the spray opening is substantially between 3 mm and 5 mm.
Claim 7
Dependent Claim
14 words
A spray device according to claim 5, wherein said distance is substantially 4 mm.
Claim 8
Dependent Claim
17 words
A spray device according to claim 5, wherein the spray opening has the form of a slot.
Claim 9
Dependent Claim
48 words
A spray device according to claim 7, wherein the slot which forms the spray opening extends symmetrically and transversely with respect to the radial center of the powder channel, and extends within the channel wall means in upstream direction to beyond the downstream end of the gas outlet.
Claim 10
Dependent Claim
51 words
A spray device according to claim 8, wherein the slot which forms the spray opening extends upstream up to a distance of substantially 5 mm to 10 mm from a conical apex defined by a conical outer surface of the channel wall means adjacent the conical section of the powder channel.
Claim 11
Dependent Claim
15 words
A spray device according to claim 9, wherein said last-mentioned distance is substantially 8 mm.
Claim 12
Dependent Claim
43 words
A spray device according to claim 9, wherein the downstream end of the electrode and the downstream end of the gas outlet are substantially 0.5 mm to 1.5 mm downstream of the upstream starting point of the conical section of the powder channel.
Claim 13
Dependent Claim
33 words
A spray device according to claim 11, wherein the transverse dimensions of the spray opening slot are substantially 15-28 mm in length measured along the outer end surface and 3-5 mm in width.
Claim 14
Dependent Claim
27 words
A spray device according to claim 12, wherein the transverse dimensions of the spray opening slot are substantially 25 mm in length and 4 mm in width.
Claim 15
Dependent Claim
21 words
A spray device according to claim 6, wherein said coatable powder forms a flat spray jet downstream from said spray opening.
Claim 16
Independent Claim
200 words
A method of forming a powder spray jet for coating articles with powder, comprising the steps of: passing coating powder through an elongated powder channel and discharging it at a spray opening at a downstream end thereof; transmitting gas through at least one gas channel which has at least one gas outlet, the gas channel and its gas outlet being arranged substantially in the radial center of said powder channel upstream of its spray opening and discharging axially downstream toward said spray opening; and supplying high voltage to at least one electrode disposed for having gas from the gas channel flow around it, said electrode being located in the gas outlet and having a downstream electrode end terminating substantially at the downstream end of the gas outlet; damming and compacting the powder before it is discharged, in a damming region formed in the powder channel at a generally conical section thereof which becomes narrower substantially from the gas outlet to the spray opening in the downstream direction, and into which the gas outlet debouches; the radial center of the spray opening being located substantially at the point of the smallest diameter of the channel section and opposite the gas outlet.
Claim 17
Independent Claim
200 words
A method of forming a powder spray jet for coating articles with powder, comprising the steps of: passing coating powder through an elongated powder channel and discharging it at a spray opening at a downstream end thereof; transmitting gas through at least one gas channel which has at least one gas outlet, the gas channel and its gas outlet being arranged substantially in the radial center of said powder channel upstream of its spray opening and discharging axially downstream toward said spray opening; and supplying high voltage to at least one electrode disposed for having gas from the gas channel flow around it, said electrode being located in the gas outlet and having a downstream electrode end terminating substantially at the downstream end of the gas outlet; damming and compacting the powder before it is discharged, in a damming region formed in the powder channel at a generally conical section thereof which becomes narrower substantially from the gas outlet to the spray opening in the downstream direction, and into which the gas outlet debouches; the radial center of the spray opening being located substantially at the point of the smallest diameter of the channel section and opposite the gas outlet.
Claim 18
Dependent Claim
22 words
A method according to claim 15, wherein said coating powder forms a compacted and electrostatically charged powder mass in said damming region.
Claim 19
Dependent Claim
27 words
A method according to claim 16, wherein an angle defined by conical surfaces of the conical section of the powder channel is substantially between 100° and 140°.
Claim 20
Dependent Claim
12 words
A method according to claim 17, wherein the angle is substantially 120°.
Claim 21
Dependent Claim
33 words
A method according to claim 17, wherein a distance from the downstream end of the gas outlet to the downstream end of the spray opening is substantially between 3 mm and 5 mm.
Claim 22
Dependent Claim
13 words
A method according to claim 19, wherein said distance is substantially 4 mm.
Claim 23
Dependent Claim
16 words
A method according to claim 19, wherein the spray opening has the form of a slot.
Claim 24
Dependent Claim
21 words
A spray device according to claim 6, wherein said coatable powder forms a flat spray jet downstream from said spray opening.
Claim 25
Dependent Claim
47 words
A method according to claim 24, wherein the slot which forms the spray opening extends symmetrically and transversely with respect to the radial center of the powder channel, and extends within the channel wall means in upstream direction to beyond the downstream end of the gas outlet.
Claim 26
Dependent Claim
50 words
A method according to claim 23, wherein the slot which forms the spray opening extends upstream up to a distance of substantially 5 mm to 10 mm from a conical apex defined by a conical outer surface of the channel wall means adjacent the conical section of the powder channel.
Claim 27
Dependent Claim
14 words
A method according to claim 24, wherein said last-mentioned distance is substantially 8 mm.
Claim 28
Dependent Claim
42 words
A method according to claim 24, wherein the downstream end of the electrode and the downstream end of the gas outlet are substantially 0.5 mm to 1.5 mm downstream of the upstream starting point of the conical section of the powder channel.
Claim 29
Dependent Claim
32 words
A method according to claim 26, wherein the transverse dimensions of the spray opening slot are substantially 15-28 mm in length measured along the outer end surface and 3-5 mm in width.
Claim 30
Dependent Claim
26 words
A method according to claim 27, wherein the transverse dimensions of the spray opening slot are substantially 25 mm in length and 4 mm in width.
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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) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |