US3767971A - Static bleed resistor - Google Patents

Static bleed resistor Download PDF

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Publication number
US3767971A
US3767971A US00140461A US3767971DA US3767971A US 3767971 A US3767971 A US 3767971A US 00140461 A US00140461 A US 00140461A US 3767971D A US3767971D A US 3767971DA US 3767971 A US3767971 A US 3767971A
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United States
Prior art keywords
bleed resistor
static
static bleed
tow
resistor
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Expired - Lifetime
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US00140461A
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English (en)
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A Patrick
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Avco Corp
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Avco Corp
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Publication date
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05F—STATIC ELECTRICITY; NATURALLY-OCCURRING ELECTRICITY
    • H05F3/00—Carrying-off electrostatic charges

Definitions

  • ABSTRACT This invention covers a drain for electrostatic charge commonly called a static bleed resistor in which a resistance element forms the core of a composite structure which includes a non-tracking plastic resinous material.
  • the core may be made from a fibrous tow, and in this event, one end of the fibers making up the tow may be exposed to the atmosphere to constitute the active bleeding elements.
  • INV E NTOR STATIC BLEED RESISTOR The prevention of the buildup of an electrostatic charge on an insulated conducting body is typically accomplished with a sharp pointed conducting rod attached to the body. The charge concentrates, typically, at the point. Because of the high charge density at the sharp point, ionization of the surrounding air occurs and the charge bleeds away. Generally, in most applications, it is necessary to limit the current that flows through the bleeder resistor to prevent sparking. This is accomplished by making the resistance means of the rod very high, several million ohms.
  • the static bleed resistor must also be able to withstand lightening strikes to the body that it is protecting because it is in itself the logical point of exodus for the lightening bolt from the body into the surrounding atmosphere.
  • a static bleed resistor which (1) is self-healing; (2) is resistant to atmospheric erosion and other deteriorating effects of the atmosphere; (3) contains an internal resistance network provided with an essentially non-conducting surface so that it can be used in improved lightening handling techniques; (4) is formed from a non-tracking matrix to maintain an essentially non-conducting surface when raised to temperatures where tracking materials char; and (5) contains a fibrous tow resistance element which prevents lightening penetration.
  • a static bleed resistor comprises an electrical resistance element substantially enclosed within a non-tracking plastic resin matrix.
  • the resistor is provided with an electrical coupling means for coupling the resistance element to the body which the static bleed resistor is intended to protect.
  • a discharge means is also provided.
  • the resistance element is formed from a fibrous tow formed from electrically conducting material.
  • the terminal edges of one end of the tow may be exposed to the atmosphere so that each exposed fiber edge acts as the means for coupling the static charge to the atmosphere, a discharge means.
  • FIG. 1 of the drawing is a cross-sectional representation of a static bleed resistor embodying the principles of the present invention.
  • FIG. 2 is an end view taken along line 22 showing in detail the static bleeding means.
  • FIG. 3 is a pictorial representation of the static bleed resistor in an operational assembly.
  • FIG. 1 of the drawing there is shown a static bleed resistor comprising an electrical resistance means 13 embedded within a plastic matrix ll.
  • the static bleed resistor 10 is coupled to a metal body 12 through an electrical coupling means 20.
  • the body 12 represents figuratively the member from which static electricity is to be bled.
  • the electrical coupling means 20 is preferably an electrically conductive adhesive such as the adhesive sold under the designation C34 made by the National Carbon Company. Chromerics and Emerson Cummings are two other sources of conductive adhesive.
  • a conducting adhesive is essentially an adhesive loaded with carbon, silver or other conductor.
  • the electrical coupling means may comprise a threading recess portion in the body 12 with a complementary threaded end of the static bleed resistor 10.
  • the static bleed resistor 10 is a composite structure with an electrical resistance means 13 embedded within a non-conducting plastic matrix 11.
  • the electrical resistance means 13 is represented by a fibrous tow made up from either continuous carbon filaments or staple carbon fibers.
  • the tow is made up of an extremely large number about 105 of extremely high resistance fibers to prevent lightening from penetrating into the tow via an occasional fiber that may be near or at the surface of the bleeder resistor.
  • the tow is constructed from carbon filaments formed, as is widely done from a cellulose material such as rayon or from PAN or acronym for polyacylatonitrile.
  • a cellulose material such as rayon or from PAN or acronym for polyacylatonitrile.
  • Other filaments such as glass coated filaments are also applicable.
  • the specific resistance material is not critical, though the resistance per unit length of the filament is.
  • each filament should exceed 10" ohms. Accordingly, in the order of 100,000, about 14 micron in diameter filaments are required to make up a static bleed resistor. Typically, static bleed resistors are 8-10 inches long and have a total longitudinal resistance of 5 X 10 to 100 X 10 ohms.
  • the electrical resistance means 13 is made up of a large number of parallel essentially insulated longitudinal electrical conducting paths for the electrostatic charge to traverse. Theoretically, there are as many parallel essentially insulated longitudinal electrical conductingpaths as-there are filaments, for example. Additionally, there are a number of finite interconnections between the parallel fibers so that if one or a number of paths formed by the length of a fiber is broken, it may be circumvented by a parallel path through a pair of interconnections.
  • non-conducting and preferably a non-tracking, plastic matrix.
  • nontracking as applied to the plastic resin matrix 11 is hereby defined to mean a material which does not form a carbonacious or other electrically conducting path when thermally dissipated as might occur by a spark or an arc discharge.
  • Typical non-tracking matrix materials are homoor copolymers of polyformaldehyde such as Delrin and Celcon.
  • An epoxy-urethane system sold by the Assignee as the 21 system as well as the fluorocarbons known as Teflon and Kel-F are also suitable non-tracking materials.
  • the preferable means involves the use of fibers, a small number of these fibers will appear at the surface of the plastic as shown by the symbol 15 in FIG. 1. These do not materially affect the operation of the static bleed resistor because these surface penetrations are essentially isolated because of the high fiber and high overall resistance. They also tend to disappear due to environmental erosion or by distruction during a lightening strike. It may be accurately stated that the surface of the static bleed resistor consistsof essentially the non-tracking matrix material, except for the discharge end 17 where the fiber ends are deliberately exposed.
  • the static bleed resistor contains a static bleed means which in this case comprises the discharge end 17.
  • the end 17 is in the form of a sharp pointed cone to concentrate the static electricity and to simplify the ionization of the surrounding air so that the static electricity may be bled from the resister 10 to the atmosphere. 5
  • ends 16 of the fiber resistance means 13 exposed to the atmosphere on the surface of the conical discharge end17.
  • Each of these ends exposed per se represents a high electrical stress region so that each one I acts as an effective coupling means between the static bleed resistor 10 and the atmosphere.
  • Each of these ends 16 acts as a substitute for the tip of a metal cap, the conventional discharge end.
  • the static bleed resistor 10 is shown within an assembly.
  • the assembly includes in addition to the static bleed resistor, a metal sleeve 23, securely fastened to the cylindrical surface of the static bleed resistor 10.
  • the metal sleeve does not affect the performance of the static bleed resistor since it is isolated from the electrical resistance means 13 by the plastic matrix 11.
  • the metal sleeve 23 operates to protect the static bleed resistor in the event of a lightening strike to the body 12.
  • the flow of electricity tends to gravitate to the static bleed resistor 10 on the body in an ionized sheath along the surface of the body.
  • the lightening bolt would, if it could, enter the resistor and traverse the resistance element. If this occurs, the static bleed resistor would be destroyed. This, in fact, occurs in prior art devices. It does not happen on the static bleedresistor described herein.
  • the lightening traveling along the surface of the body encounters either the matrix or an isolated fiber.
  • the air surrounding the static bleed resistor offers less resistance than the fiber having 10 inches ohm/in. Characteristically, therefore, the air around the static bleed resistor is converted .into an ionized sheath. The lightening current is dissipated into the atmosphere through this sheath.
  • the lightening strike ionizes the air between the body 12 and around the metal sleeve 23. Since the metalsleeve 23 covers the major portion of the static bleed resistor surface, most of the lightening current is dissipated around the metal sleeve. The sleeve is able to withstand damage because of its excellent conductive qualties. The exposed surface areas of the static bleed resistor 10 are stressed less, and to the extent that the surfaces are burned, there is no conducting residue from the non-tracking matrix. The metal sleeve merely increases the reliability of the static bleed resistor against lightening strikes; its presence is not a necessity.
  • a static bleed resistor comprising a longitudinal resistance element having a large number of parallel and essentially insulated longitudinal electrical conducting paths embedded within a non-tracking plastic matrix, each of said conducting paths having a resistance per length of about 10 ohms per inch.

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  • Elimination Of Static Electricity (AREA)
US00140461A 1971-05-05 1971-05-05 Static bleed resistor Expired - Lifetime US3767971A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US14046171A 1971-05-05 1971-05-05

Publications (1)

Publication Number Publication Date
US3767971A true US3767971A (en) 1973-10-23

Family

ID=22491328

Family Applications (1)

Application Number Title Priority Date Filing Date
US00140461A Expired - Lifetime US3767971A (en) 1971-05-05 1971-05-05 Static bleed resistor

Country Status (5)

Country Link
US (1) US3767971A (enExample)
CA (1) CA958787A (enExample)
DE (1) DE2221622A1 (enExample)
FR (1) FR2135619B1 (enExample)
GB (1) GB1393012A (enExample)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3898526A (en) * 1971-06-01 1975-08-05 Charles D Hendricks Static discharge apparatus and several methods for manufacturing the static discharge apparatus
US4698723A (en) * 1986-04-24 1987-10-06 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Lightning discharge protection rod
US4733268A (en) * 1986-05-09 1988-03-22 International Business Machines Corporation Voltage control bar for electrophotography
US5570265A (en) * 1989-01-31 1996-10-29 Hr Smith (Technical Developments) Limited Static dischargers for aircraft
US5871060A (en) * 1997-02-20 1999-02-16 Jensen; Kenneth M. Attachment geometry for non-planar drill inserts
US20050002165A1 (en) * 2002-11-26 2005-01-06 Samsung Electronics Co., Ltd Laser diode for optical pickup and method of protection
WO2009120785A3 (en) * 2008-03-25 2009-12-30 Ebr Systems, Inc. Implantable wireless acoustic stimulators with high energy conversion efficiencies
US20100234924A1 (en) * 2008-03-25 2010-09-16 Ebr Systems, Inc. Operation and estimation of output voltage of wireless stimulators
US9180285B2 (en) 2008-03-25 2015-11-10 Ebr Systems, Inc. Implantable wireless accoustic stimulators with high energy conversion efficiencies
US11654287B2 (en) 2019-08-30 2023-05-23 Ebr Systems, Inc. Pulse delivery device including slew rate detector, and associated systems and methods

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3305616A1 (de) * 1983-02-18 1984-08-23 Vorwerk & Co Interholding Gmbh, 5600 Wuppertal Vorrichtung zur vermeidung elektrostatischer aufladungen
DE3931230A1 (de) * 1989-09-20 1991-03-28 Neuero Stahlbau Gmbh & Co Magnetbahn

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2631189A (en) * 1950-01-27 1953-03-10 Dayton Aircraft Prod Inc Static wick discharger
US3034020A (en) * 1960-06-27 1962-05-08 Dayton Aircraft Prod Inc Static discharger
US3473087A (en) * 1962-05-22 1969-10-14 Raybestos Manhattan Inc Electrically conductive polytetrafluoroethylene tubing
US3617805A (en) * 1970-03-02 1971-11-02 Dayton Aircraft Prod Inc Low-noise static discharger device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2631189A (en) * 1950-01-27 1953-03-10 Dayton Aircraft Prod Inc Static wick discharger
US3034020A (en) * 1960-06-27 1962-05-08 Dayton Aircraft Prod Inc Static discharger
US3473087A (en) * 1962-05-22 1969-10-14 Raybestos Manhattan Inc Electrically conductive polytetrafluoroethylene tubing
US3617805A (en) * 1970-03-02 1971-11-02 Dayton Aircraft Prod Inc Low-noise static discharger device

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3898526A (en) * 1971-06-01 1975-08-05 Charles D Hendricks Static discharge apparatus and several methods for manufacturing the static discharge apparatus
US4698723A (en) * 1986-04-24 1987-10-06 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Lightning discharge protection rod
US4733268A (en) * 1986-05-09 1988-03-22 International Business Machines Corporation Voltage control bar for electrophotography
US5570265A (en) * 1989-01-31 1996-10-29 Hr Smith (Technical Developments) Limited Static dischargers for aircraft
US5871060A (en) * 1997-02-20 1999-02-16 Jensen; Kenneth M. Attachment geometry for non-planar drill inserts
CN1525609B (zh) * 2002-11-26 2012-02-29 三星Led株式会社 用于光拾取器的激光二极管和保护方法
US20050002165A1 (en) * 2002-11-26 2005-01-06 Samsung Electronics Co., Ltd Laser diode for optical pickup and method of protection
US9180285B2 (en) 2008-03-25 2015-11-10 Ebr Systems, Inc. Implantable wireless accoustic stimulators with high energy conversion efficiencies
US20100234924A1 (en) * 2008-03-25 2010-09-16 Ebr Systems, Inc. Operation and estimation of output voltage of wireless stimulators
US8364276B2 (en) 2008-03-25 2013-01-29 Ebr Systems, Inc. Operation and estimation of output voltage of wireless stimulators
WO2009120785A3 (en) * 2008-03-25 2009-12-30 Ebr Systems, Inc. Implantable wireless acoustic stimulators with high energy conversion efficiencies
US9343654B2 (en) 2008-03-25 2016-05-17 Ebr Systems, Inc. Method of manufacturing implantable wireless acoustic stimulators with high energy conversion efficiencies
US9981138B2 (en) 2008-03-25 2018-05-29 Ebr Systems, Inc. Operation and estimation of output voltage of wireless stimulators
US10052493B2 (en) 2008-03-25 2018-08-21 Ebr Systems, Inc. Implantable wireless accoustic stimulators with high energy conversion efficiencies
US10512785B2 (en) 2008-03-25 2019-12-24 Ebr Systems, Inc. Implantable wireless accoustic stimulators with high energy conversion efficiencies
US10806938B2 (en) 2008-03-25 2020-10-20 Ebr Systems, Inc. Implantable wireless accoustic stimulators with high energy conversion efficiencies
US11712572B2 (en) 2008-03-25 2023-08-01 Ebr Systems, Inc. Implantable wireless acoustic stimulators with high energy conversion efficiencies
US12465777B2 (en) 2008-03-25 2025-11-11 Ebr Systems, Inc. Implantable wireless acoustic stimulators with high energy conversion efficiencies
US11654287B2 (en) 2019-08-30 2023-05-23 Ebr Systems, Inc. Pulse delivery device including slew rate detector, and associated systems and methods
US12427319B2 (en) 2019-08-30 2025-09-30 Ebr Systems, Inc. Pulse delivery device including slew rate detector, and associated systems and methods

Also Published As

Publication number Publication date
CA958787A (en) 1974-12-03
DE2221622A1 (de) 1972-11-09
GB1393012A (en) 1975-05-07
FR2135619A1 (enExample) 1972-12-22
FR2135619B1 (enExample) 1973-07-13

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