US4027607A — Pulsed powder application system

Claim 1

Independent Claim 153 words

An aparatus for electrostatically powder-coating a substrate occupying a coating position adjacent thereto, comprising in combination: applicator bed means positioned in the vicinity of said coating position for holding electrostatic powder particles, and carrying a pair of electrodes; fluidizing means adjacent to and operatively associated with said applicator bed means for acting on said electrostatic powder to endow it with fluid-like characteristics; and pulsing means connected to said pair of electrodes and having a first state for applying a high voltage pulse to said electrodes for a predetermined coating time so as to effect ionization of said electrostatic powder particles whereby to cause the establishment of an electric field attracting said electrostatic powder particles to said substrate, and having a second state for removing said high voltage pulse from said pair of electrodes whereby to cause the establishment of a reverse electric field attracting said ionized electrostatic powder particles away from said substrate.

Claim 2

Dependent Claim 153 words

An aparatus for electrostatically powder-coating a substrate occupying a coating position adjacent thereto, comprising in combination: applicator bed means positioned in the vicinity of said coating position for holding electrostatic powder particles, and carrying a pair of electrodes; fluidizing means adjacent to and operatively associated with said applicator bed means for acting on said electrostatic powder to endow it with fluid-like characteristics; and pulsing means connected to said pair of electrodes and having a first state for applying a high voltage pulse to said electrodes for a predetermined coating time so as to effect ionization of said electrostatic powder particles whereby to cause the establishment of an electric field attracting said electrostatic powder particles to said substrate, and having a second state for removing said high voltage pulse from said pair of electrodes whereby to cause the establishment of a reverse electric field attracting said ionized electrostatic powder particles away from said substrate.

Claim 3

Dependent Claim 71 words

Apparatus of claim 1 including a feeder bed means for holding said electrostatic powder when not in use for coating, additional fluidizing means adjacent to and operatively associated with said feeder bed means for acting on said electrostatic powder in said feeder bed means to fluidize it, and pump means extending between said feeder bed means and said applicator bed means for providing said fluidized powder to said applicator bed means.

Claim 4

Dependent Claim 53 words

Apparatus of claim 2 including level control means operatively associated with said applicator bed means and said feeder bed means for controlling the level of said electrostatic powder in said applicator bed means by draining off the excess powder over a predetermined level, said excess powder being returned to said feeder bed means.

Claim 5

Dependent Claim 35 words

Apparatus of claim 1 including mask means carried by said applicator bed means and positioned between said applicator bed means and said substrate for causing said substrate to be electrostatically coated in selected areas only.

Claim 6

Dependent Claim 43 words

Apparatus of claim 1 including shutter means carried by said applicator bed means and having a first condition for allowing coating of said substrate by said electrostatic powder and having a second condition for inhibiting coating of said substrate by said electrostatic powder.

Claim 7

Dependent Claim 21 words

Apparatus of claim 5 wherein said shutter means is a mechanical shutter positioned between said applicator bed means and said substrate.

Claim 8

Dependent Claim 39 words

Apparatus of claim 5 wherein said shutter means comprises air manifold means for creating an air curtain between said applicator bed means and said substrate so as to inhibit coating of said substrate whereby to establish said second condition.

Claim 9

Dependent Claim 67 words

Apparatus of claim 5 including shutter control means connected to said shutter means for moving the latter alternatively to said first and second conditions, and proximity sensing means positioned adjacent to said coating position for sensing when said substrate is in said coating position, and operatively associated with said shutter control means for causing said shutter control means to move said shutter means to said first condition.

Claim 10

Dependent Claim 72 words

Apparatus of claim 8 wherein said proximity sensing means provides an open-shutter signal when said substrate is in said coating position, and including time delay means connected to said proximity sensing means for receiving said open-shutter signal, and responsive thereto for transmitting to said pulsing means, after a predetermined period of delay, a pulse-on signal, said pulsing means being responsive thereto to apply said high voltage pulse to said pair of electrodes.

Claim 11

Dependent Claim 29 words

Apparatus of claim 1 wherein said fluidizing means includes a porous plate means positioned in horizontally level orientation for supporting and maintaining the powder in said applicator bed means.

Claim 12

Dependent Claim 16 words

Apparatus of claim 10 wherein said plate means includes means for mounting said pair of electrodes.

Claim 13

Dependent Claim 37 words

Apparatus of claim 1 wherein said applicator bed means has small dimensions so as to minimize the required magnitude of said electric field whereby to minimize the magnitude of said voltage pulse applied by said pulsing means.

Claim 14

Dependent Claim 74 words

Apparatus of claim 1 wherein said fluidizing means includes an air chamber located adjacent to said applicator bed means and remote from said substrate, air compressor means connected to said air chamber for providing a pressurized air flow into said chamber, and porous plate means disposed between said air chamber and said applicator bed means for conveying said pressurized air flow to said applicator bed means whereby to fluidize said electrostatic powder contained therein.

Claim 15

Dependent Claim 75 words

Apparatus of claim 2 wherein said additional fluidizing means includes an air chamber located adjacent to said feeder bed means and remote from said substrate, air compressor means connected to said air chamber for providing a pressurized air flow into said chamber, and porous plate means disposed between said air chamber and said feeder bed means for conveying said pressurized air flow to said feeder bed means whereby to fluidize said electrostatic powder contained therein.

Claim 16

Dependent Claim 42 words

Apparatus of claim 14 wherein said feeder bed means includes air exhaust means for conveying said pressurized air flow and any stray electrostatic powder carried by said air flow, out of said feeder bed means whereby to recover said stray electrostatic powder.

Claim 17

Dependent Claim 70 words

Apparatus of claim 1 wherein said pulsing means includes voltage means for providing said high voltage pulse, said apparatus also including coating initiator means positioned adjacent to said coating position for sensing when said substrate is in said coating position, and connected to said voltage means for transmitting a pulse-on signal thereto, said voltage means being responsive to said pulse-on signal for applying said high voltage pulse to said electrodes.

Claim 18

Dependent Claim 78 words

Apparatus of claim 16 wherein said pulsing means includes additional time delay means connected to said coating initiator means for receiving and delaying said pulse-on signal so as to generate a pulse-off signal a predetermined time interval, equal to said predetermined coating time, after the reception of said pulse-on signal, said voltage means being connected to said additional time delay means for receiving said pulse-off signal and responsive thereto for connecting said pair of electrodes to electrical ground.

Claim 19

Dependent Claim 97 words

Apparatus of claim 17 including shutter means carried by said applicator bed means and having a first condition for allowing coating of said substrate by said electrostatic powder and having a second condition for inhibiting coating of said substrate by said electrostatic powder, and shutter control means connected to said shutter means for moving the latter alternatively to said first and second conditions, said additional time delay means being connected to said shutter control means for transmitting said pulse-off signal thereto, said shutter control means being responsive thereto for moving said shutter means to said second condition.

Claim 20

Dependent Claim 104 words

Apparatus of claim 17 wherein said voltage means includes D.C. circuit means connected in series with said pair of electrodes to form a closed electrical loop for applying said high voltage to said pair of electrodes during said first state, and relay means in parallel with said pair of electrodes and actuable to an open circuit condition for forcing the application of said high voltage to said pair of electrodes during said first state and actuable to a closed circuit condition for short-circuiting said pair of electrodes to inhibit the application of said high voltage to said pair of electrodes during said second state.

Claim 21

Dependent Claim 54 words

Apparatus of claim 19 wherein said relay means is an electronic switch connected to said coating initiator means for receiving said pulse-on signal and responsive thereto for assuming said open circuit condition, and connected to said additional time delay means for receiving said pulse-off signal and responsive thereto for assuming said closed circuit condition.

Claim 22

Dependent Claim 45 words

Apparatus of claim 19 wherein said D.C. circuit means has two terminals each connected to a respective one of said pair of electrodes, a given one of said terminals and said respective one of said pair of electrodes being connected to a common electrical ground.

Claim 23

Dependent Claim 89 words

Apparatus of claim 16 wherein said pulsing means includes additional time delay means connected to said coating initiator means for receiving and delaying said pulse-on signal so as to generate a pulse-off signal a predetermined time interval, equal to said predetermined coating time, after the reception of said pulse-on signal, said voltage means being connected to said additional time delay means for receiving said pulse-off signal and responsive thereto for applying to said electrodes a reverse high voltage pulse with polarity opposite to that of said high voltage pulse.

Claim 24

Dependent Claim 128 words

Apparatus of claim 22 wherein said voltage means includes first D.C. circuit means connected in series with said pair of electrodes for providing said high voltage pulse to said pair of electrodes during said first state, second D.C. circuit means connected in series with said pair of electrodes for providing said reverse high voltage pulse to said pair of electrodes during said second state, and switch means between said pair of electrodes, on the one hand, and said first and second D.C. circuit means, on the other hand, and having a first position for applying said high voltage pulse to said pair of electrodes during said first state and a second position for applying said reverse high voltage pulse to said pair of electrodes during said second state.

Claim 25

Dependent Claim 49 words

Apparatus of claim 23 wherein said switch means is connected to said coating initiator means for receiving said pulse-on signal and responsive thereto for assuming said first position, and connected to said additional time delay means for receiving said pulse-off signal in response thereto for assuming said second position.

Claim 26

Dependent Claim 15 words

Apparatus of claim 1 wherein said substrate to be coated is a can end unit.

Claim 27

Independent Claim 186 words

An apparatus for electrostatically powdercoating a substrate occupying a coating position adjacent thereto, comprising in combination: feeder bed means for receiving and for holding electrostatic powder to be used for coating; fluidizing means adjacent to and operatively associated with said feeder bed means for fluidizing said electrostatic powder in said feeder bed means; applicator bed means positioned in the vicinity of said coating position for holding said electrostatic powder during coating; pump means extending between said feeder bed means and said applicator bed means for providing said fluidized powder to said applicator bed means; additional fluidizing means adjacent to and operatively associated with said applicator bed means for fluidizing said electrostatic powder in said applicator bed means; and pulsing means connected to said applicator bed means for applying a high voltage discharge to said electrostatic powder for a predetermined coating time so as to effect ionization of said electrostatic powder whereby to cause the establishment of an electric field attracting said electrostatic powder particles to said substrate and including means to establish a reverse electric field whereby to attract excess powder particles away from said substrate.

Claim 28

Independent Claim 186 words

An apparatus for electrostatically powdercoating a substrate occupying a coating position adjacent thereto, comprising in combination: feeder bed means for receiving and for holding electrostatic powder to be used for coating; fluidizing means adjacent to and operatively associated with said feeder bed means for fluidizing said electrostatic powder in said feeder bed means; applicator bed means positioned in the vicinity of said coating position for holding said electrostatic powder during coating; pump means extending between said feeder bed means and said applicator bed means for providing said fluidized powder to said applicator bed means; additional fluidizing means adjacent to and operatively associated with said applicator bed means for fluidizing said electrostatic powder in said applicator bed means; and pulsing means connected to said applicator bed means for applying a high voltage discharge to said electrostatic powder for a predetermined coating time so as to effect ionization of said electrostatic powder whereby to cause the establishment of an electric field attracting said electrostatic powder particles to said substrate and including means to establish a reverse electric field whereby to attract excess powder particles away from said substrate.

Claim 29

Dependent Claim 53 words

Apparatus of claim 26 including level control means operatively associated with said applicator bed means and said feeder bed means for controlling the level of said electrostatic powder in said applicator bed means by draining off the excess powder over a predetermined level, said excess powder being returned to said feeder bed means.

Claim 30

Dependent Claim 35 words

Apparatus of claim 26 including mask means carried by said applicator bed means and positioned between said applicator bed means and said substrate for causing said substrate to be electrostatically coated in selected areas only.

Claim 31

Dependent Claim 43 words

Apparatus of claim 26 including shutter means carried by said applicator bed means and having a first condition for allowing coating of said substrate by said electrostatic powder and having a second condition for inhibiting coating of said substrate by said electrostatic powder.

Claim 32

Dependent Claim 21 words

Apparatus of claim 29 wherein said shutter means is a mechanical shutter positioned between said application bed means and said substrate.

Claim 33

Dependent Claim 39 words

Apparatus of claim 29 wherein said shutter means comprises air manifold means for creating an air curtain between said applicator bed means and said substrate so as to inhibit coating of said substrate whereby to establish said second condition.

Claim 34

Dependent Claim 67 words

Apparatus of claim 29 including shutter control means connected to said shutter means for moving the latter alternatively to said first and second conditions, and proximity sensing means positioned adjacent to said coating position for sensing when said substrate is in said coating position, and operatively associated with said shutter control means for causing said shutter control means to move said shutter means to said first condition.

Claim 35

Dependent Claim 71 words

Apparatus of claim 32 wherein said proximity sensing means provides an open-shutter signal when said substrate is in said coating position, and including time delay means connected to said proximity sensing means for receiving said open-shutter signal, and responsive thereto for transmitting to said pulsing means, after a predetermined period of delay, a pulse-on signal, said pulsing means being responsive thereto to apply said high voltage pulse to said electrostatic powder.

Claim 36

Dependent Claim 29 words

Apparatus of claim 26 wherein said fluidizing means includes a porous plate means positioned in horizontally level orientation for supporting and maintaining the powder in said applicator bed means.

Claim 37

Dependent Claim 37 words

Apparatus of claim 26 wherein said applicator bed means has small dimensions so as to minimize the required magnitude of said electric field whereby to minimize the magnitude of said voltage pulse applied by said pulsing means.

Claim 38

Dependent Claim 74 words

Apparatus of claim 26 wherein said fluidizing means includes an air chamber located adjacent to said feeder bed means and remote from said substrate, air compressor means connected to said air chamber for providing a pressurized air flow into said chamber, and porous plate means disposed between said air chamber and said feeder bed means for conveying said pressurized air flow to said feeder bed means whereby to fluidize said electrostatic powder contained therein.

Claim 39

Dependent Claim 42 words

Apparatus of claim 36 wherein said feeder bed means includes air exhaust means for conveying said pressurized air flow and any stray electrostatic powder carried by said air flow, out of said feeder bed means whereby to recover said stray electrostatic powder.

Claim 40

Dependent Claim 75 words

Apparatus of claim 26 wherein said additional fluidizing means includes an air chamber located adjacent to said applicator bed means and remote from said substrate, air compressor means connected to said air chamber for providing a pressurized air flow into said chamber, and porous plate means disposed between said air chamber and said applicator bed means for conveying said pressurized air flow to said applicator bed means whereby to fluidize said electrostatic powder contained therein.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1980-06-06	1980-12-06	1981-06-07	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1984-06-06	1984-12-06	1985-06-07	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1988-06-06	1988-12-06	1989-06-07	$7700.00	Window Closed / Lapsed

Pulsed powder application system

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