Apparatus for dispensing conductive coating materials having multiple flow paths
AssigneeNordson Corporation
InventorRonald D. Konieczynski
Life of this patent
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Abstract
An apparatus is provided for transferring electrically conductive coating materials, such as water-based paint, from a source to at least one coating dispenser such as a spray gun for discharge onto a substrate. In alternative embodiments, the coating material is supplied to the dispenser(s) from parallel flow paths which are comparatively simple and inexpensive in construction, and which are capable of delivering high pressure, high volume flows of coating material while substantially eliminating pressure fluctuations in the coating material supply when switching from one flow path to another.
Claims22
Apparatus for transmitting electrically conductive coating material to at least one electrostatic coating dispenser, comprising:
- a first supply unit and a second supply unit, said first supply unit including a first transfer device having a reservoir and a voltage block connected to said reservoir, said second supply unit including a second transfer device having a reservoir and a voltage block connected to said reservoir;
- a control device for controlling the operation of said first and second supply units, said control device including:
- (i) a first sensor operative to produce a first signal when the coating material within said reservoir of said first transfer device is depleted to a selected level;
- (ii) at least one first control element operative to initiate the flow of coating material from said reservoir of said second transfer device to the coating dispenser, in response to said first signal, while the flow of coating material from said first transfer device to the coating dispenser is continued;
- (iii) a second sensor operative to produce a second signal after said second transfer device has supplied coating material to the coating dispenser;
- (iv) at least one second control element operative to stop the flow of coating material from said first transfer device in response to said second signal.
Apparatus for transmitting electrically conductive coating material to at least one electrostatic coating dispenser, comprising:
- a first supply unit and a second supply unit, said first supply unit including a first transfer device having a reservoir and a voltage block connected to said reservoir, said second supply unit including a second transfer device having a reservoir and a voltage block connected to said reservoir;
- a control device for controlling the operation of said first and second supply units, said control device including:
- (i) a first sensor operative to produce a first signal when the coating material within said reservoir of said first transfer device is depleted to a selected level;
- (ii) at least one first control element operative to initiate the flow of coating material from said reservoir of said second transfer device to the coating dispenser, in response to said first signal, while the flow of coating material from said first transfer device to the coating dispenser is continued;
- (iii) a second sensor operative to produce a second signal after said second transfer device has supplied coating material to the coating dispenser;
- (iv) at least one second control element operative to stop the flow of coating material from said first transfer device in response to said second signal;
- a color changer device, associated with each of said first and second supply units, which is operative to empty said first and second transfer devices of coating material, to allow the introduction of a cleaning fluid into said first and second transfer units, and then to introduce a coating material of a different color into said reservoir of each said first and second transfer devices in preparation for a new coating operation.
A method of transmitting electrically conductive coating material to at least one electrostatic coating dispenser, comprising:
- transmitting coating material from a first supply unit to an electrostatic coating dispenser;
- producing a first signal, by operation of a first sensor, when the quantity of coating material within the first supply unit is depleted to a selected level;
- initiating the flow of coating material from a second supply unit to the electrostatic coating dispenser, in response to the first signal, while continuing the flow of coating material to the electrostatic coating dispenser from the first supply unit;
- producing a second signal, by operation of a second sensor, after the second supply unit has been supplying coating material to the dispenser;
- stopping the flow of coating material from the first supply unit in response to the second signal.
A method of transmitting electrically conductive coating material to at least one electrostatic coating dispenser, comprising:
- transmitting coating material from the reservoir of a first piston pump having a piston rod to an electrostatic coating dispenser;
- sensing the position of the piston rod of the first piston pump by operation of a first sensor of the first piston pump as the reservoir of the first piston pump empties, and transmitting a first signal from the first sensor when the quantity of coating material within said reservoir is depleted to a selected level;
- initiating the flow of coating material to the electrostatic coating dispenser from the reservoir of a second piston pump having a piston rod, in response to said first signal, while continuing the flow of coating material from the first piston pump;
- sensing the position of the piston rod of the second piston pump by operation of a second sensor as the reservoir of the second piston pump empties, and transmitting a second signal from the second sensor after the second piston pump has been supplying coating material to the coating dispenser;
- stopping the flow of coating material from the first piston pump in response to the second signal.
Dependencies are inferred from the claim text.