Patent US3541320A successfully refreshed from Google Patents.
US3870233A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color change of electrostatic spray apparatus
Assignee: Nordson Corp
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Filing: 1973-09-12
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Granted: 1975-03-11
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Expires: 1993-09-12
Abstract
Abstract An electrostatic spray system for spraying multiple colors of material or multiple materials through a single common gun, including apparatus for spraying solvent through the gun between color or material changes. The system includes a dump valve for connecting the spray gun to a waste tank upon a color change so that the old color plus a solvent for purging the system of the old color may be pumped to the waste tank upon a color change. The dump valve is mounted directly upon the spray gun and is made from non-metallic, low capacitance material so that it does not store an electrical potential sufficient to create a dangerous condition in a spray environment and so that it does not leak or bleed excessive electrical potential from the system and thereby destroy its deposition efficiency.
Inventors
- 👤 Frederick R Wilhelm
- 👤 Donald R Hastings
- 👤 William W Lyth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:47
CPC Classifications
B; B05; B05B; B05B5/00; B05B5/16; B05B12/00; B05B12/08; B05B12/085; B05B12/087; B05B12/088; B05B12/14; B05B15/00; B05B15/50; B05B15/55; B05B12/149
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
232 words
An electrostatic spray system for selectively spraying any one of a plurality of spray materials from a common spray gun, which system comprises a spray gun having a spray material flow passage terminating in an outlet orifice and a selectively operable valve for controlling the emission of spray material from said orifice, means including a high voltage power supply for applying an electrical charge to spray material as it is emitted from said spray gun, a plurality of spray material reservoirs and a solvent reservoir, means including an electrical control circuit for selectively connecting any one of said reservoirs to said spray gun so as to enable spray material to be supplied from a selected reservoir to said gun, a dump tank, and a dump valve operatively connected to the spray material flow passage of said gun and operable when opened to bypass spray material from said flow passage to said dump tank, said dump valve being positioned immediately adjacent said gun and made from components which have a capacitance sufficiently low as to preclude said dump valve from storing a potentially dangerous electrical charge, said dump valve comprising a valve housing, said housing having an inlet port and an outlet port interconnected by a dump flow passage, and a needle valve element located within said dump flow passage and operable to control the flow of spray material through said dump valve.
Claim 2
Dependent Claim
232 words
An electrostatic spray system for selectively spraying any one of a plurality of spray materials from a common spray gun, which system comprises a spray gun having a spray material flow passage terminating in an outlet orifice and a selectively operable valve for controlling the emission of spray material from said orifice, means including a high voltage power supply for applying an electrical charge to spray material as it is emitted from said spray gun, a plurality of spray material reservoirs and a solvent reservoir, means including an electrical control circuit for selectively connecting any one of said reservoirs to said spray gun so as to enable spray material to be supplied from a selected reservoir to said gun, a dump tank, and a dump valve operatively connected to the spray material flow passage of said gun and operable when opened to bypass spray material from said flow passage to said dump tank, said dump valve being positioned immediately adjacent said gun and made from components which have a capacitance sufficiently low as to preclude said dump valve from storing a potentially dangerous electrical charge, said dump valve comprising a valve housing, said housing having an inlet port and an outlet port interconnected by a dump flow passage, and a needle valve element located within said dump flow passage and operable to control the flow of spray material through said dump valve.
Claim 3
Dependent Claim
232 words
An electrostatic spray system for selectively spraying any one of a plurality of spray materials from a common spray gun, which system comprises a spray gun having a spray material flow passage terminating in an outlet orifice and a selectively operable valve for controlling the emission of spray material from said orifice, means including a high voltage power supply for applying an electrical charge to spray material as it is emitted from said spray gun, a plurality of spray material reservoirs and a solvent reservoir, means including an electrical control circuit for selectively connecting any one of said reservoirs to said spray gun so as to enable spray material to be supplied from a selected reservoir to said gun, a dump tank, and a dump valve operatively connected to the spray material flow passage of said gun and operable when opened to bypass spray material from said flow passage to said dump tank, said dump valve being positioned immediately adjacent said gun and made from components which have a capacitance sufficiently low as to preclude said dump valve from storing a potentially dangerous electrical charge, said dump valve comprising a valve housing, said housing having an inlet port and an outlet port interconnected by a dump flow passage, and a needle valve element located within said dump flow passage and operable to control the flow of spray material through said dump valve.
Claim 4
Dependent Claim
232 words
An electrostatic spray system for selectively spraying any one of a plurality of spray materials from a common spray gun, which system comprises a spray gun having a spray material flow passage terminating in an outlet orifice and a selectively operable valve for controlling the emission of spray material from said orifice, means including a high voltage power supply for applying an electrical charge to spray material as it is emitted from said spray gun, a plurality of spray material reservoirs and a solvent reservoir, means including an electrical control circuit for selectively connecting any one of said reservoirs to said spray gun so as to enable spray material to be supplied from a selected reservoir to said gun, a dump tank, and a dump valve operatively connected to the spray material flow passage of said gun and operable when opened to bypass spray material from said flow passage to said dump tank, said dump valve being positioned immediately adjacent said gun and made from components which have a capacitance sufficiently low as to preclude said dump valve from storing a potentially dangerous electrical charge, said dump valve comprising a valve housing, said housing having an inlet port and an outlet port interconnected by a dump flow passage, and a needle valve element located within said dump flow passage and operable to control the flow of spray material through said dump valve.
Claim 5
Dependent Claim
22 words
The electrostatic spray system of claim 1 in which said dump valve is physically attached to and supported from said spray gun.
Claim 6
Dependent Claim
21 words
The electrostatic spray system of claim 1 in which said components of said dump valve are all made from non-metallic materials.
Claim 7
Dependent Claim
30 words
The electrostatic spray system of claim 1 in which all of said components of said dump valve which are exposed to contact with said spray material are made from non-metals.
Claim 8
Dependent Claim
29 words
The electrostatic spray system of claim 1 in which said dump valve includes a fluid motor for controlling positioning of said needle valve element within said dump flow passage.
Claim 9
Dependent Claim
27 words
The electrostatic spray system of claim 5 in which said needle valve element is mounted within a piston, said piston being slideable within said dump valve passage.
Claim 10
Dependent Claim
42 words
The electrostatic spray system of claim 6 in which said fluid motor includes a flexible diaphragm and a fluid motor chamber, said diaphragm being located between and sealingly separating said dump flow passage from said fluid motor chamber of said dump valve.
Claim 11
Dependent Claim
73 words
The electrostatic spray system of claim 7 in which said dump valve includes a valve seat located within said dump flow passage, said piston including a section in slideable contact with a wall section of said dump flow passage of said dump valve, said section of said piston being shaped as a sector of a sphere so as to enable said piston mounted needle valve element to be self-centering within said valve seat.
Claim 12
Dependent Claim
22 words
The electrostatic spray system of claim 8 in wHich said dump valve is physically attached to and supported from said spray gun.
Claim 13
Dependent Claim
21 words
The electrostatic spray system of claim 9 in which said components of said dump valve are all made from non-metallic materials.
Claim 14
Dependent Claim
38 words
The electrostatic spray system of claim 10 in which said dump valve housing and said piston are made from a plastic material and in which said needle valve and needle valve seat are made from a ceramic material.
Claim 15
Dependent Claim
22 words
The electrostatic spray system of claim 11 in which said diaphragm biases said piston and needle valve to a normally closed position.
Claim 16
Dependent Claim
21 words
The electrostatic spray system of claim 7 in which said components of said dump valve are all made from non-metallic materials.
Claim 17
Dependent Claim
115 words
A dump valve for use in an electrostatic spray system for selectively spraying any one of a plurality of spray materials from a common spray gun, which dump valve comprises a valve housing having an inlet port and an outlet port interconnected by a dump flow passage, a movable valve element located within said dump flow passage and operable to control the flow of spray material through said dump valve, said dump valve being made from components which have a capacitance sufficiently low as to preclude said dump valve from storing a potentially dangerous electrical charge so that said dump valve is adapted to be positioned immediately adjacent the common spray gun of said system.
Claim 18
Dependent Claim
115 words
A dump valve for use in an electrostatic spray system for selectively spraying any one of a plurality of spray materials from a common spray gun, which dump valve comprises a valve housing having an inlet port and an outlet port interconnected by a dump flow passage, a movable valve element located within said dump flow passage and operable to control the flow of spray material through said dump valve, said dump valve being made from components which have a capacitance sufficiently low as to preclude said dump valve from storing a potentially dangerous electrical charge so that said dump valve is adapted to be positioned immediately adjacent the common spray gun of said system.
Claim 19
Dependent Claim
27 words
The dump valve of claim 14 in which said dump valve further includes means for attaching said housing to and supporting it from an electrostatic spray gun.
Claim 20
Dependent Claim
20 words
The dump valve of claim 15 in which the components of said dump valve are all made from non-metallic materials.
Claim 21
Dependent Claim
29 words
The dump valve of claim 15 in which all of the components of said dump valve which are exposed to contact with said spray material are made from non-metals.
Claim 22
Dependent Claim
27 words
The dump valve of claim 14 in which said dump valve includes a fluid motor for controlling positioning of said valve element within said dump flow passage.
Claim 23
Dependent Claim
28 words
The dump valve of claim 18 in which said valve element is secured to and mounted upon a piston, said piston being slideable within said dump valve passage.
Claim 24
Dependent Claim
41 words
The dump valve of claim 19 in which said fluid motor includes a flexible diaphragm and a fluid motor chamber, said diaphragm being located between and sealingly separating said dump flow passage from said fluid motor chamber of said dump valve.
Claim 25
Dependent Claim
20 words
The dump valve of claim 20 in which said diaphragm biases said piston mounted needle valve to a closed position.
Claim 26
Dependent Claim
79 words
The dump valve of claim 19 which further includes a valve seat located within said dump flow passage, said movable valve element being a needle valve element and said piston including a section in slideable contact with a wall section of said dump flow passage of said dump valve, said section of said piston being shaped as a sector of a sphere so as to enable said piston mounted needle valve element to be self-centering within said valve seat.
Claim 27
Dependent Claim
37 words
The dump valve of claim 22 in which said dump valve housing and said piston are made from a plastic material and in which said needle valve element and valve seat are made from a ceramic material.
Claim 28
Dependent Claim
41 words
The dump valve of claim 23 in which said fluid motor includes a flexible diaphragm and a fluid motor chamber, said diaphragm being located between and sealingly separating said dump flow passage from said fluid motor chamber of said dump valve.
Claim 29
Dependent Claim
22 words
The dump valve of claim 24 in which said diaphragm biases said piston mounted needle valve element to a normally closed position.
Claim 30
Dependent Claim
83 words
The dump valve of claim 14 which further includes a valve seat located within said dump flow passage, said movable valve element being a needle valve element mounted upon a movable piston, said piston including a section in slideable contact with a wall section of said dump flow passage of said dump valve, said section of said piston being shaped as a sector of a sphere so as to enable said piston mounted needle valve Element to be self-centering within said valve seat.
References Cited (Backward Citations)
US3219273A
Cited
US3317141A
Cited
US3348774A
Cited
US3450092A
Cited
US3412931A
Cited
US3610285A
Cited
US3672570A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-10 | 1978-09-09 | 1979-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-10 | 1982-09-09 | 1983-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-10 | 1986-09-09 | 1987-03-11 | $7700.00 | Window Closed / Lapsed |