High voltage sealing and isolation via dynamic seals
AssigneeGraco Inc.
InventorsYamin Ma, Lawrence J. Lunzer, Norman N. Fender
Life of this patent
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Abstract
A liquid pumping system for transporting conductive liquids to an electrostatic spraying device while maintaining electrical isolation between the spraying device and the liquid source; the system includes sequentially-arranged metering valves and pumps to sequentially transport predetermined and isolated quantities of liquid.
Claims13
An apparatus for conveying conductive liquids to an electrostatic spraying device for providing electrical isolation of the liquid source from the spraying device, comprising:
- a) a first metering valve in liquid flow communication with said liquid source, said first metering valve having an outlet port;
- b) a liquid pump having an inlet in flow communication with said first metering valve outlet port, and having an outlet check valve;
- c) a second metering valve in liquid flow communication with said pump outlet check valve, said second metering valve having an outlet port;
- d) an electrostatic spray device in flow communication with said second metering valve outlet port;
- and
- e) control means for sequentially filling said first metering valve with a predetermined volume of said liquid, and for transporting said predetermined volume to said pump, said second metering valve and said spray device, so that said predetermined volume does not simultaneously contact said first and second metering valves.
An apparatus for conveying conductive liquids to an electrostatic spraying device for providing electrical isolation of a conductive liquid source from the spraying device, comprising:
- a) a first pump having an inlet connected to said conductive liquid source, and having a first outlet;
- b) a second pump having an inlet connected to said first outlet, and having a second outlet;
- c) a third pump having an inlet connected to said second outlet and having a third outlet;
- d) wherein each of said first, second and third pumps further comprise a piston reciprocable within a cylinder, said piston having an annular groove therein;
- and a nonconductive seal filling said annular groove;
- e) first, second and third control valves respectively connected to said inlets of said first, second and third pumps.
- f) a spraying device connected to said third outlet;
- and
- g) means for sequentially driving said first, second and third pumps to sequentially move a volume of said conductive liquid from said liquid source to said spraying device comprising means for sequentially controlling said first, second and third control valves.
Dependencies are inferred from the claim text.