US3443570A - High voltage isolator for liquid feedline - Google Patents

High voltage isolator for liquid feedline Download PDF

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Publication number
US3443570A
US3443570A US3443570DA US3443570A US 3443570 A US3443570 A US 3443570A US 3443570D A US3443570D A US 3443570DA US 3443570 A US3443570 A US 3443570A
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US
United States
Prior art keywords
feedline
bubble
gas
liquid
fluid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
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English (en)
Inventor
Harry J King
Jerome H Molitor
James W Ward
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Raytheon Co
Original Assignee
Hughes Aircraft Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hughes Aircraft Co filed Critical Hughes Aircraft Co
Application granted granted Critical
Publication of US3443570A publication Critical patent/US3443570A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00—Cosmonautic vehicles
    • B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
    • B64G1/40—Arrangements or adaptations of propulsion systems
    • B64G1/402—Propellant tanks; Feeding propellants
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03H—PRODUCING A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03H1/00—Using plasma to produce a reactive propulsive thrust
    • F03H1/0006—Details applicable to different types of plasma thrusters
    • F03H1/0012—Means for supplying the propellant
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00—Cosmonautic vehicles
    • B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
    • B64G1/40—Arrangements or adaptations of propulsion systems
    • B64G1/411—Electric propulsion
    • B64G1/413—Ion or plasma engines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
    • B64G1/00—Cosmonautic vehicles
    • B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
    • B64G1/40—Arrangements or adaptations of propulsion systems
    • B64G1/411—Electric propulsion
    • B64G1/415—Arcjets or resistojets
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/0318—Processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/2931—Diverse fluid containing pressure systems
    • Y10T137/3003—Fluid separating traps or vents
    • Y10T137/3084—Discriminating outlet for gas
    • Y10T137/309—Fluid sensing valve
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/8593—Systems
    • Y10T137/87571—Multiple inlet with single outlet
    • Y10T137/87652—With means to promote mixing or combining of plural fluids
    • Y10T137/8766—With selectively operated flow control means

Definitions

  • High voltage isolation between the ends of the liquid feedline is provided by injecting a bubble of insulative material into the feedline.
  • the method preferably includes sensing the existence of a previously injected bubble at a downstream point and using the signal to inject another bubble. It also includes removing the insulating bubble from the feedline.
  • the apparatus includes a bulbble injector, a downstream bubble sensor connected to drive the bubble injector and a bubble remover downstream from the bubble sensor.
  • This invention relates to fluid feed systems and more particularly to a method and apparatus for providing electrical isolation between the ends of a fluid feedline adapted to feed conductive fluid.
  • electrical isolation is accomplished by injecting an insulating gas bubble into the conductive liquid in the feedline at a point adjacent the inlet of the feedline, removing the gas bubble from the feedline at a point adjacent the outlet thereof, sensing the presence of a bubble as it approaches the outlet, and control-lably injecting another bubble into the line in response to a signal from the sensor indicating the presence of such a bubble, there assuring at least one bubble in the line at all times.
  • the system of the present invention serves to interrupt or open the conductive path which previously existed in the feedline. Any voltage drops along the feedline will appear entirely across the gas bubble.
  • the insulating properties of the gas bubbles are determined from the Paschen curve for the particular gas employed. For all pressures above torr, an air bubble of .5 cm. length can hold off several kilovolts without breakdown.
  • FIG. is a cross sectional, partly schematic view of a preferred embodiment of the present invention.
  • the invention will be described below by reference to the preferred embodiment thereof in which the feedline is used to carry liquid mercury to an ion thruster.
  • the figure shows a liquid mercury feedline 2 for supplying liquid mercury propellant from a common manifold or propellant reservoir (not shown) to a liquid mercury cathode incorporated in a liquid mercury electron bombardment ion thrustor (not shown).
  • the wall of the feedline 2 should be constructed of an insulating material such as glass, ceramic or Teflon, which will not be wet 'by the conductive liquid. This will aid in maintaining the configuration of the figure where the two sections of the conducting fluid are completely separated by the gas bubble.
  • gas bubbles are injected into the mercury 4 which is flowing through the feedline 2 as follows.
  • a gas reservoir 6 supplies the insulating gas through a gas flow line 8 provided with suitable one-way valves 10 and 12 which assure gas flow in the proper direction.
  • the gas flow line 8 is connected to the feedline 2 at an opening 14 therein adjacent the inlet of the line 2.
  • Gas bubbles 15 are injected into the liquid 4 from the gas reservoir 6 by an electromagnetically driven bellows 16 which forms a contractable chamber.
  • a portion of the feedline 2 is formed with a porous-walled section 18.
  • the material forming the porous wall can be, for example, porous tungsten.
  • the porous section 18 is surrounded by an evacuated housing 20, provide with a pump 22 for maintaining the vacuum.
  • the housing 20 and pump 22 can be dispensed with.
  • the material of which the porous section 18 is composed must be such as to allow the passage therethrough of the gas which is used to form the gas bubbles while preventing the passage therethrough of the liquid 4.
  • While the injection of the gas bubbles into the liquid 4 can be controlled in any one of a number of ways, such as manually or at predetermined intervals by the use of a simple timer-actuated pump or syringe, a preferred automatic method is shown in the figure. If, as in an ion thrustor system, the cathode is at a high positive potential (several thousand volts) and the mercury reservoir is at ground potential, then a coaxial capacitor 24 (which can be plated onto the outside of the feedline 2) can be used to sense the change in potential when a bubble passes through that section of the feedline 2 surrounded by the capacitor 24. The capacitor 24 is connected to ground through two resistors R and R connected in series.
  • the capacitor 24 is connected to a pulser 26 through the junction between R, and R
  • the pulser 26 thus receives a signal each time a bubble 15 passes through the capacitor 24.
  • the pulser 26 is connected to solenoid 30 which is activated by the pulser 26 upon receiving a triggering signal from the capacitor 24.
  • Air other gases can be used
  • the pulser can take a variety of configurations depending on the exact application.
  • One embodiment is to use a thyratron or SCR, which is triggered by the signal from the capacitor 24, in series with a capacitor and the coil of the solenoid.
  • the capacitor is charged by an auxiliary circuit.
  • the thyratron or other switch allows a pulse of current to pass through'the' solenoid thus driving bubble of gas into the feedline 2.
  • the bubble it is necessary to remove the bubble from the feedline to prevent it from affecting the operation of the cathode.
  • An insulating liquid can be used to form a bubble for use in the present invention rather than a gas as described above with respect to the preferred embodiment. In such a case if the liquid forming the insulating bubble does not affect the operation of the feed device, it can be left in the feedline. If it does affect the operation of the device, it can be removed by a simple valve for draining the portion of the fluid containing the bubble.
  • the opeartion of the valve can be controlled by a simple bubble-sensing means upstream of the valve
  • Another method of removing the insulating material forming the bubble from the feedline is to use an insulating material which is either more or less dense than the fluid being fed through the line and to feed the fluid into a centrifugal separator.
  • the present invention is not limited in use to the preferred embodiment described above involving high power ion thrustor systems but is useful in any application involving the flow of a conductive fluid through a conduit in which application it is desired to electrically isolate the two ends of the feedline.
  • a method for providing electrical isolation between the ends of a fluid feedline composed of insulating material and adapted to carry conductive fluid comprising:
  • said insulating fluid material is a gas and in which said removing step comprises passing said gas through a porous wall section of said feedline, said porous section allowing the passage therethrough of said gas but preventing the passage therethrough of said conductive material.
  • Apparatus for electricaly isolating the ends of a fluid feed line comprising:
  • an insulating fluid feedline adapted to carry a conductive fluid
  • injector means for injecting an insulating fluid into said line adjacent the inlet of the line, which insulating fluid is adapted to form a bubble in the conductive fluid so as to interrupt the electrical continuity of the conductive fluid;
  • sensing means positioned downstream from said injector means for detecting a bubble in the feedline adjacent said detecting means, said sensing means being connected to said injector means so that when said detecting means detects a bubble in said feedline said injector means injects another bubble in said feedline;
  • said removing means comprises a porous walled section of the feedline encased in an evacuated container, the porous wall allowing the passage therethrough of the insulating fluid but preventing the passage therethrough of the conductive fluid.
  • Apparatus for electrically isolating individual thrustors connected to liquid mercury propellant feedlines in a liquid mercury ion thrustor system comprising:
  • injector means for injecting a quantity of insulating gas sufiicient to form a gas bubble extending across the entire width of the feedline so as to interrupt the electrical continuity of the mercury in the feedline, said bubble being adapted to flow downstream with the liquid mercury, said injector means comprising a contractible chamber containing insulating gas and means to contract said chamber to expell insulating gas from said chamber and inject it into the feedline,
  • said removing means comprising a porous-walled section of the feedline surrounded by an evacuated container, said porous-walled section allowing the passage therethrough of the gas but preventing the passage therethrough of liquid mercury;
  • sensing means for sensing, at a point adjacent to but 2,694,404 11/1954 Alexander 1371 upstream from the point at which the bubble is re- 2 9 5 114 12 1960 Harden 137 1 moved from the feedline the existence of a bubble 3,033,911 5/1962 D u d dy 137 197 X in the feedhne, said sensing means being connected 3 1 6 Sk X to said means to contract said chamber so that when 09714 11 19 3 eggs a bubble is sensed by said sensing means, said chamher is contracted to inject another bubble in said ALAN COHAN, Examine"- feedline to continue to interrupt electrical continuity.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Remote Sensing (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Geophysics And Detection Of Objects (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
US3443570D 1967-01-03 1967-01-03 High voltage isolator for liquid feedline Expired - Lifetime US3443570A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US60661167A 1967-01-03 1967-01-03

Publications (1)

Publication Number Publication Date
US3443570A true US3443570A (en) 1969-05-13

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Family Applications (1)

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US3443570D Expired - Lifetime US3443570A (en) 1967-01-03 1967-01-03 High voltage isolator for liquid feedline

Country Status (5)

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US (1) US3443570A (de)
CH (1) CH471970A (de)
DE (1) DE1640407B1 (de)
GB (1) GB1198673A (de)
SE (1) SE341739B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3646960A (en) * 1969-04-25 1972-03-07 Lkb Produkter Ab Injection and dosing arrangements
US3895641A (en) * 1968-08-28 1975-07-22 Stephen C Jacobsen Fluid system and method for coding information
US4313739A (en) * 1979-10-01 1982-02-02 Avco Everett Research Laboratory, Inc. Removal of contaminants from gases

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2627933A (en) * 1947-06-28 1953-02-10 Sinclair Refining Co Aerogel diffusion unit
US2694404A (en) * 1952-09-24 1954-11-16 Du Pont Nitroglycerin transport
US2965114A (en) * 1957-10-14 1960-12-20 Shell Oil Co Method and apparatus for controlling the pumping of fluids in a pipeline
US3033911A (en) * 1958-07-30 1962-05-08 Electric Storage Battery Co Vent plug
US3109714A (en) * 1959-07-22 1963-11-05 Technicon Instr Means for separating fluids from each other

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2627933A (en) * 1947-06-28 1953-02-10 Sinclair Refining Co Aerogel diffusion unit
US2694404A (en) * 1952-09-24 1954-11-16 Du Pont Nitroglycerin transport
US2965114A (en) * 1957-10-14 1960-12-20 Shell Oil Co Method and apparatus for controlling the pumping of fluids in a pipeline
US3033911A (en) * 1958-07-30 1962-05-08 Electric Storage Battery Co Vent plug
US3109714A (en) * 1959-07-22 1963-11-05 Technicon Instr Means for separating fluids from each other

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3895641A (en) * 1968-08-28 1975-07-22 Stephen C Jacobsen Fluid system and method for coding information
US3646960A (en) * 1969-04-25 1972-03-07 Lkb Produkter Ab Injection and dosing arrangements
US4313739A (en) * 1979-10-01 1982-02-02 Avco Everett Research Laboratory, Inc. Removal of contaminants from gases

Also Published As

Publication number Publication date
CH471970A (de) 1969-04-30
GB1198673A (en) 1970-07-15
SE341739B (de) 1972-01-10
DE1640407B1 (de) 1970-08-20

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