US3792409A - Electrostatic hand gun cable - Google Patents

Electrostatic hand gun cable Download PDF

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Publication number
US3792409A
US3792409A US00347240A US3792409DA US3792409A US 3792409 A US3792409 A US 3792409A US 00347240 A US00347240 A US 00347240A US 3792409D A US3792409D A US 3792409DA US 3792409 A US3792409 A US 3792409A
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United States
Prior art keywords
cable
high voltage
semiconductive
electrostatic
resistance
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Expired - Lifetime
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US00347240A
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English (en)
Inventor
W Smart
P Gregg
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Ransburg Corp
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Ransburg Corp
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Publication of US3792409A publication Critical patent/US3792409A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/0054—Cables with incorporated electric resistances

Definitions

  • An improved high voltage cable for usein electrostatic hand guns includes a semiconductive stranded fiber glass core within a semiconductive shield surrounded by body of insulative material, a flexible conductive sheath in an outer protective covering;-the semiconductive core and semiconductive shield provide resistance of not less than 20,000 and not more than 300,000 ohms per foot of cable length.
  • the present invention related to a high voltage cable for use in connecting electrostatic spray coating devices with a separate source of high voltage.
  • Electrostatic coating systems frequently use voltages on the order of 20,000-100,000 volts of direct current. Voltage of this magnitude places great stress upon electrical insulation that is used to isolate it. Being exposed to such stress, high voltage insulation can fail permitting electrical discharge of the high voltage through the body of the insulation or across its surface. In addition, such high voltages can break down surrounding air and initiate a spark that can travel through air to adjacent bodies at lower potential. Electrical isolation of such high voltages is therefore a problem.
  • Electrostatic coating systems are frequently used with coating materials that have a flammable residue or that produce flammable vapors. Spraying operations are most frequently conducted in a spray booth to confine such flammable materials and to remove them safely from the interior of an'industrial facility. The Sprayers of electrostatic coating systems are thus most frequently used. inside a spray booth.
  • the high voltage source is generally located outside of and at least feet from. the spraying area. The electrostatic charge to. be applied to the spray particles must be carried from the high voltage source to the electrostatic spray device over a distance on the order of 20 feet.
  • the high voltage conductor was a metallic wire at the center of the high voltage cable.
  • Surrounding the wire was a body of insulating material, generally a polyethylene.
  • Surrounding the polyethylene insulation was the grounded metallic braid to act as a barrier to any electric discharge which might occur in the event of an insulation failure of the dielectric material, and to prevent such an electric discharge from occurring to personnel who may be using the electrostatic hand gun.
  • a protective covering of rubber or plastic was provided as the outermost covering of the cable.
  • high voltage cables for electrostatic systems were manufactured having a central conductor made of a plurality of shortb'ut rigid high resistance segments that extended throughout the length of the cable (see U.S. Pat. No. 3,348,186). Cables of this latter type thus included many high voltage electrical connections at the junctions of the short high resistance segments. Furthermore, such cables included necessarily, a plurality of high voltage conductor surface discontinuities at these connections at which nonuniformly high potential gradients could occur. This plurality of connections of surface discontinuities was undesirable and accentuated the tendency of high voltage to break down the electricalinsulation of the cable.
  • Our invention is an electrical cable used to connect an electrostatic hand spray gun to a separate high voltage source.
  • a cable is generally on the order of at least 20 feet, although somewhat longer and shorter lengths of cable may be used. It includes a high voltage conductor which is smooth throughout its length and has a uniform distributed resistance of at least 0.5 to about 7.5 megohms equally distributed along its length.
  • the cable is thirty feet in length and has a total resistance of five megohms, or about 167,000 ohms per foot of cable length.
  • the cable is small, having an overall diameter of 7/16 of an inch. This cable solves the difficulties of providing a cable that can be reliably manufactured for commercial use and provides the flexibility needed for manipulatable hand guns, with the ability to withstand the tendency of high voltage to break down its electrical insulation.
  • FIG. 1 is a diagrammatic sketch of an electrostatic hand gun system including such a cable.
  • FIG. 2 is a cross-sectional view of the cable.
  • FIG. 1 shows an electrostatic hand gun in use in a spraying area.
  • Electrostatic hand gun 10 is connected to the high voltage source 11 by 25 feet of high voltage cable 12.
  • One such electrostatic hand gun includes within its barrel portion a high voltage resistor 13 having a resistance on the order of megohms. The high voltage for such a hand gun produces 60 kilovolts of direct current.
  • the high voltage cable 12 which carries electrostatic charge from the high voltage source to the hand gun as shown in FIG. 2, includes as the high voltage conductor 14 stranded conductive fiber glass.
  • the central conductor is comprised of many fibers each having a very small diameter. When stranded, they produce a central high voltage conductor having a diameter of 0.015 inches.
  • This stranded fiber glass conductor is treated to provide a resistance on the order of 20,000 to 300,000 ohms per foot.
  • a corona shield 15 of conductive polyethylene consisting of a homogeneous mixture of polyethylene with a small percentage of carbon black.
  • the conductive polyethylene minimizes variations of potential gradient which might occur at the surface of the high voltage conductor because of gas trapped during the manufacturing process or surface discontinuities.
  • the corona shield is typically 0.050 inches in diameter.
  • the combined resistance of the semiconductive stranded fiber glass conductor and the semiconductive corona shield should preferably measure not less than 20,000 nor more than 300,000 ohms per foot of cable length.
  • the insulation is a high grade polyethylene that isolates the high voltage charge at its center.
  • a polyethylene is typically DFD 60005 NT (Natural), manufactured by Union Carbide.
  • a conductive braid 17 Surrounding the insulation is a conductive braid 17.
  • Such a braid is comprised of 160 strands of 30-gauge copper alloy wire braided together around the insulation.
  • a sheath 18 typically 0.030 of an inch thick polyurethane. Total diameter of such a cable structure can be 7/16 inch.
  • this cable can be easily manufactured.
  • the fiber glass center conductor provides strength and flexibility needed to manufacture the cable. Furthermore, its smooth outer surface is relatively free of surface imperfections, which can accentuate the tendency of the high voltage to break down electrical insulation.
  • the fiber glass provides a chemically and dimensionally stable medium and permits a conductivity which can be controlled within the limits needed for a commercially satisfactory product. Sufficient resistance can be incorporated into the central conductor so that in the event of an insulation failure, the energy stored throughout the cable by the high voltage electric charge present on the high voltage conductor is dissipated by the resistance of the high voltage conductor as the electric charge travels down the cable to the point of the insulation failure.
  • the energy available in an electrical discharge between the high voltage conductor and the conductive braid may be limited by the action of the resistance of the high voltage conductor. Because of the reliability in achieving stable high resistance values to the high voltage conductor, it is possible to obtain a cable where the energy available in the event of an insulation failure is below the level necessary to ignite most combustible vapors and residues encountered in spray finishing operations. Incorporation of such a cable into an electrostatic hand gun system thus improves the safety of the system.
  • An electrical cable used to connect an electrostatic spray gun to a separate high voltage source said cable having a stranded fiber glass core within a semiconductive shield surrounded by a body of insulative material, a flexible conductive sheath in an outer protective covering; the improvement which consists of the core and the shield together having a resistance of not less than 20,000 and not more than 300,000 ohms perfoot of cable length the improvement which consists of the core being semiconductive and with semiconductive shield providing a resistance of not less than 20,000 and not more than 300,000 ohms per foot of cable length.
  • an electrical cable used to connect an electrostatic spray gun to a separate high voltage source said cable having a stranded fiber glass core within a semiconductive shield surrounded by a body of insulative material, a flexible conductive sheath in w an outer protective covering; the improvement which consists of the core andgjg the shield together having a resistance of not less than 20,000 and not more than 300,000 ohms per foot of cable length.

Landscapes

  • Electrostatic Spraying Apparatus (AREA)
  • Insulated Conductors (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
US00347240A 1973-04-02 1973-04-02 Electrostatic hand gun cable Expired - Lifetime US3792409A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US34724073A 1973-04-02 1973-04-02

Publications (1)

Publication Number Publication Date
US3792409A true US3792409A (en) 1974-02-12

Family

ID=23362897

Family Applications (1)

Application Number Title Priority Date Filing Date
US00347240A Expired - Lifetime US3792409A (en) 1973-04-02 1973-04-02 Electrostatic hand gun cable

Country Status (8)

Country Link
US (1) US3792409A (enrdf_load_stackoverflow)
JP (1) JPS50381A (enrdf_load_stackoverflow)
AU (1) AU472386B2 (enrdf_load_stackoverflow)
CA (1) CA991286A (enrdf_load_stackoverflow)
DE (1) DE2353809A1 (enrdf_load_stackoverflow)
FR (1) FR2223797B1 (enrdf_load_stackoverflow)
GB (1) GB1424296A (enrdf_load_stackoverflow)
IT (1) IT996889B (enrdf_load_stackoverflow)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3885085A (en) * 1974-06-11 1975-05-20 Gen Cable Corp High voltage solid extruded insulated power cables
FR2358734A1 (fr) * 1976-07-14 1978-02-10 Nordson Corp Cable electrique allonge de connexion d'un pistolet de pulverisation electrostatique
FR2456374A1 (fr) * 1978-07-22 1980-12-05 Nkf Groep Bv Cable souple pour tensions continues elevees
FR2475279A1 (fr) * 1980-01-31 1981-08-07 Sumitomo Electric Industries Cable d'allumage perfectionne
US4487057A (en) * 1980-09-16 1984-12-11 Raychem Corporation Continuous sense and locate device
US4576827A (en) * 1984-04-23 1986-03-18 Nordson Corporation Electrostatic spray coating system
US4584431A (en) * 1984-10-11 1986-04-22 Us Of America Secr Air Force High voltage RF coaxial cable
US4642417A (en) * 1984-07-30 1987-02-10 Kraftwerk Union Aktiengesellschaft Concentric three-conductor cable
US4739935A (en) * 1986-03-12 1988-04-26 Nordson Corporation Flexible voltage cable for electrostatic spray gun
US4924037A (en) * 1988-12-20 1990-05-08 W. L. Gore & Associates, Inc. Electrical cable
US4978813A (en) * 1989-08-29 1990-12-18 W. L. Gore & Associates, Inc. Electrical cable
EP0416452A3 (en) * 1989-09-05 1992-04-29 Abb Kabel Und Draht Gmbh Electro-filter cable
US5166477A (en) * 1991-05-28 1992-11-24 General Electric Company Cable and termination for high voltage and high frequency applications
US5803372A (en) * 1997-04-03 1998-09-08 Asahi Sunac Corporation Hand held rotary atomizer spray gun
EP0829883A3 (de) * 1996-09-13 1998-12-23 Schnier Elektrostatik GmbH Schwingungsfreies bedämpftes Hochspannungskabel
EP1267361A3 (en) * 2001-06-14 2003-12-17 Illinois Tool Works Inc. High voltage cable
WO2015113729A1 (de) * 2014-01-30 2015-08-06 Dürr Systems GmbH Hochspannungskabel

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5024727A (enrdf_load_stackoverflow) * 1973-06-14 1975-03-17
JPS5265164U (enrdf_load_stackoverflow) * 1975-11-10 1977-05-13
JPH02165516A (ja) * 1988-12-16 1990-06-26 Sumitomo Electric Ind Ltd 直流用高圧電線
US5034719A (en) * 1989-04-04 1991-07-23 Prestolite Wire Corporation Radio frequency interference suppression ignition cable having a semiconductive polyolefin conductive core

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB547481A (en) * 1940-05-10 1942-08-28 United Air Lines Transp Corp Improvements in or relating to electrical resistors
US2703356A (en) * 1951-02-01 1955-03-01 Gen Motors Corp High ohmic resistance conductor
US2790053A (en) * 1951-12-27 1957-04-23 Thomas F Peterson Shielded ignition cable and resistors
US3105218A (en) * 1961-06-30 1963-09-24 Fischer & Co H G Electric resistor
US3105219A (en) * 1962-02-19 1963-09-24 H G Fischer & Co Inc Electric resistor
US3167255A (en) * 1961-05-08 1965-01-26 Sames Mach Electrostat Electrostatic sprayer system having a separate high resistivity conductor
US3284751A (en) * 1963-10-11 1966-11-08 Eltra Corp Resistor ignition lead
US3348186A (en) * 1964-11-16 1967-10-17 Nordson Corp High resistance cable
DE1490618A1 (de) * 1964-07-24 1970-02-05 Sueddeutsche Kabelwerke Zweign Tempe?aturunabhaengige Widerstandszuendleitung mit thermoplastischem Masseleiter,in dessen Laengsachse ein zugfester Kern angeordnet ist
US3518606A (en) * 1968-06-27 1970-06-30 Eltra Corp Ignition cable with terminal construction
US3644866A (en) * 1971-01-11 1972-02-22 Owens Corning Fiberglass Corp Tightly bound bundle of filaments and method of producing same
US3680027A (en) * 1971-04-19 1972-07-25 Avnet Inc Ignition cable
US3683309A (en) * 1970-03-20 1972-08-08 Yazaki Corp High frequency noise prevention cable

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB547481A (en) * 1940-05-10 1942-08-28 United Air Lines Transp Corp Improvements in or relating to electrical resistors
US2703356A (en) * 1951-02-01 1955-03-01 Gen Motors Corp High ohmic resistance conductor
US2790053A (en) * 1951-12-27 1957-04-23 Thomas F Peterson Shielded ignition cable and resistors
US3167255A (en) * 1961-05-08 1965-01-26 Sames Mach Electrostat Electrostatic sprayer system having a separate high resistivity conductor
US3105218A (en) * 1961-06-30 1963-09-24 Fischer & Co H G Electric resistor
US3105219A (en) * 1962-02-19 1963-09-24 H G Fischer & Co Inc Electric resistor
US3284751A (en) * 1963-10-11 1966-11-08 Eltra Corp Resistor ignition lead
DE1490618A1 (de) * 1964-07-24 1970-02-05 Sueddeutsche Kabelwerke Zweign Tempe?aturunabhaengige Widerstandszuendleitung mit thermoplastischem Masseleiter,in dessen Laengsachse ein zugfester Kern angeordnet ist
US3348186A (en) * 1964-11-16 1967-10-17 Nordson Corp High resistance cable
US3518606A (en) * 1968-06-27 1970-06-30 Eltra Corp Ignition cable with terminal construction
US3683309A (en) * 1970-03-20 1972-08-08 Yazaki Corp High frequency noise prevention cable
US3644866A (en) * 1971-01-11 1972-02-22 Owens Corning Fiberglass Corp Tightly bound bundle of filaments and method of producing same
US3680027A (en) * 1971-04-19 1972-07-25 Avnet Inc Ignition cable

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3885085A (en) * 1974-06-11 1975-05-20 Gen Cable Corp High voltage solid extruded insulated power cables
FR2358734A1 (fr) * 1976-07-14 1978-02-10 Nordson Corp Cable electrique allonge de connexion d'un pistolet de pulverisation electrostatique
US4103276A (en) * 1976-07-14 1978-07-25 Nordson Corporation Resistor core cable
FR2456374A1 (fr) * 1978-07-22 1980-12-05 Nkf Groep Bv Cable souple pour tensions continues elevees
FR2475279A1 (fr) * 1980-01-31 1981-08-07 Sumitomo Electric Industries Cable d'allumage perfectionne
US4487057A (en) * 1980-09-16 1984-12-11 Raychem Corporation Continuous sense and locate device
AU572987B2 (en) * 1984-04-23 1988-05-19 Nordson Corp. Electrostatic spray
US4576827A (en) * 1984-04-23 1986-03-18 Nordson Corporation Electrostatic spray coating system
US4642417A (en) * 1984-07-30 1987-02-10 Kraftwerk Union Aktiengesellschaft Concentric three-conductor cable
US4584431A (en) * 1984-10-11 1986-04-22 Us Of America Secr Air Force High voltage RF coaxial cable
US4739935A (en) * 1986-03-12 1988-04-26 Nordson Corporation Flexible voltage cable for electrostatic spray gun
US4924037A (en) * 1988-12-20 1990-05-08 W. L. Gore & Associates, Inc. Electrical cable
US4978813A (en) * 1989-08-29 1990-12-18 W. L. Gore & Associates, Inc. Electrical cable
EP0416452A3 (en) * 1989-09-05 1992-04-29 Abb Kabel Und Draht Gmbh Electro-filter cable
US5166477A (en) * 1991-05-28 1992-11-24 General Electric Company Cable and termination for high voltage and high frequency applications
EP0829883A3 (de) * 1996-09-13 1998-12-23 Schnier Elektrostatik GmbH Schwingungsfreies bedämpftes Hochspannungskabel
US5803372A (en) * 1997-04-03 1998-09-08 Asahi Sunac Corporation Hand held rotary atomizer spray gun
EP1267361A3 (en) * 2001-06-14 2003-12-17 Illinois Tool Works Inc. High voltage cable
US20050178578A1 (en) * 2001-06-14 2005-08-18 Gorrell Brian E. High voltage cable
WO2015113729A1 (de) * 2014-01-30 2015-08-06 Dürr Systems GmbH Hochspannungskabel
US20170011819A1 (en) * 2014-01-30 2017-01-12 Dürr Systems GmbH High-voltage cable
US10811167B2 (en) * 2014-01-30 2020-10-20 Dürr Systems Ag High-voltage cable

Also Published As

Publication number Publication date
AU6165773A (en) 1975-04-24
FR2223797B1 (enrdf_load_stackoverflow) 1976-10-01
JPS50381A (enrdf_load_stackoverflow) 1975-01-06
GB1424296A (en) 1976-02-11
DE2353809A1 (de) 1974-10-10
CA991286A (en) 1976-06-15
AU472386B2 (en) 1976-05-20
FR2223797A1 (enrdf_load_stackoverflow) 1974-10-25
IT996889B (it) 1975-12-10

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