US2289389A

US2289389A - Current interrupting apparatus

Info

Publication number: US2289389A
Application number: US321868A
Authority: US
Inventors: Charles L Stroup
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-03-02
Filing date: 1940-03-02
Publication date: 1942-07-14
Anticipated expiration: 1959-07-14

Description

y 1942- c. L. STROUP CURRENT INTERRUPTING. APPARA'IfUS Filed March 2, 1940 T0 l/NE 22 I 22 I 2/ a cmrzeszsm Patented July 14, 1942 UNITED STATES PATENT- OFFICE T T T .-2,2s9,3s9 T CURRENT m'rannur'rmc APPARATUS Charles L. Stroup, Oak Park, m'. Application March 2, 1940,- Serial Nb. 321,868 (Cl. i'zs-aoi i 13 Claims.

My invention relates generally to electrical apparatus and it has particular relation to cur-. rent interrupting apparatus such as lightning arre'sters, in which arc extinction is efiected by means of a blast resulting from the creation of the arc and acting to blow out or cut oil the arc.

An object of my invention is to provide for extinguishing an arc in 'a new and improved manner by directing across a'section of its created as a result of the arc.

Another object of my invention is to provide for extinguishing an are by placing a pair of electrodes at the open ends of a restricted arc passageway so that a blast created therein by an arc will extinguish the are at either or both of the open ends. I

Another object of my invention is to provide for extinguishing an are by placing an electrode to the side of an arc passageway so that a blast created therein by an arc will cut ofi or blow out the arc where it changes direction toward the electrode.

Still another object of my invention is to provide for extinguishing an' are between a pair of electrodes by causing the arc to make a sharp change in direction from its main or general path, and cutting off the are where it changes direction by a blast moving in a direction generally parallel to the main path of the arc.

Another important object of my invention is to prevent the puncture or bursting of a lightning arrester housing due to heavy electric arcs, by placing the electrodes of the arrester in from the sides of the housing.

Other objects of my invention will in part be obvious and in part appear hereinafter.

Accordingly, my invention is disclosed in the embodiment thereof shown in the accompanying drawing, and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the appended claims.

path a blast Figure 1 is a vertical sectionalview through a lightning arrester unit illustrating one w'orlring embodiment of my invention;

Figure 2 is a sectional view, taken on line 2-2 ofFi'gurehand j I Figure 3 is a view takenon line 3+3 of Figure 1.

While I have chosen to disclose my invention 1 as employed in a lightning arrester, it will be apparent that it may also be employed for use in other types of current interrupter, such as fuses or circuit breakers;

For a more completeunderstanding of the.

nature and scope of my invention, reference may be had to the following detailed description,

taken in conjunction drawing, in which with the accompanying Referring now to Figures 1, 2 and 3 of the drawing, a lightningarrester unit is indicated generally at Ill, comprising a fiber-tube'or housing with a fiber cylinder l2 fitting closely therein approximatelymidway between the open ends. Preferably, the cylinder I2 is of such size that it may be easily inserted into the tube II with substantially no 'play therebetween. The narrow clearance between the cylinder l2 and the inside of the casing ll provides a. restricted arc passage l3, the width of which is shown greatly exaggerated in the drawing for purposes of illustration.

The lightning arrester l0 shown in the drawingrepresents an actual working embodiment of my invention and is shown in approximately full scale dimensions in Figures 1, 2 and 3. The tube or casing H is 10 inches long with an outside diameter of 2 inches. The cylinder I2 is 1% inches in height and has a diameter of 11-} inches. The width of the arc passageway I3, or the clearance between the cylinder l2 and inside of the casing I I, isapproximately 3.0 thousandths of an inch in the working device shown. T

A pair of disc-shaped electrodes I may be provided on opposite sides of the fiber cylinder l2, having bosses l5 fitting into recesses in the faces of the fiber cylinder II to maintainalignment. The electrodes ll may be machined down so as to leave shoulders l6 at the faces abutting the cylinder 12. A pair of inner metal sleeves I1 and a pair of outer fiber sleeves l8 fit over the machined, portion of the electrodes M and rest against the shoulders Hi. It is not essential to the operation of the lightning arrester III that the sleeves I8 be formed of fiber. The ends of the metal sleeves l1 and fiber sleeves l8 maybe closed by a pair of washers. IS. The fiber sleeves l8'are of somewhat less diameter than the inside the sleeves l8 are about 2%. inches long and have a diameter of 11-} inches. And the annular spaces 2 0 are about inch in radial width.

A pair of end plugs '2! may be screwed; into, the ends of the fiber tube I I, having a plurality of apertures 22 for outlet or discharge blast gases from within the lightning arrester unit it]. In order to connect the lightning arrester unit in electrical relationship between line and ground, a pair of terminals 23 in the form of bolts may be screwed centrally through the plugs 2| and into threaded recesses in the electrodes 14, as shown. An air gap, such as a sphere gap or a horn gap, should be provided in the line connection, according {to standard practice, in order to prevent subjecting the lightning arrester unit III to continuous line voltage, with resultant leakage current and to avoid the voltage hazard of a live piece of equipment.

Several difierent insulation materials other than hard fiber may be used. for the casing H,

cylinder l2, and the sleeves l8. Any material which evolves arc extinguishing gases under the heat of an electric 'arc may-have the necessary are extinguishing properties. Certain woods, vegetable fiber, impregnated paper, and chemical compounds give of! arc extinguishing gases. Wood, fiber, paper and the like yield gases by destructive distillation. These gases probably comprise both water vapor and lower hydrocarbons. Chemicals, such as boric acid, yield water vapor by having water of crystallization driven oil by the heat of the arc.

The operation of the lightning arrester unit- It may be explained as follows: The height of the fiber cylinder. l2 and corresponding distance between the electrodes I 4 largely determines the discharge rating or capacity of the lightning arrester unit it). When the voltage impressed on the lightning arrester unit It exceeds its discharge rating, an arc will be established between the electrodes l4. Such an arc will be formed between opposite points of the peripheries of the shoulders l6 through the narrow or restricted space between the fiber cylinder i2 and the inside of the tube II. It will be noted that the main path of such an arc is parallel with the axis of the tube H but that the arc must turn in at each end to reach the opposing points on the shoulders I6. Having the shoulders It thus inset a. short way from the periphery of the faces of the cylinder I 2 serves to aid in the extinguishment of an arc. Gases will be driven oil from the cylinder 12 and tube H by the arc flowing therebetween to create a blast which moves with tremendous velocity out the opposite ends of the narrrow space between the cylinder l2 and the inside of the tube H, into the relatively open annular spaces 29. It will be seen that this blast moves in a direction generally normal to the portions of the are which turn in to reach the shoulders l6. Such a transverse blast either cuts off the turned-in or normal portions of the are immediately at the edges of the cylinder H, or forces the arc in loop form up into the open annular spaces 20, Where its extinguishment is aided by the gases evolved from the fiber sleeves l8 and the tube H. The end plugs 21 are spaced sufliciently far from the electrodes I4 so that there is no possibility of the arc restriking or being extended therebetween, or, if necessary, the plugs 2| may be made of insulating material.

An are established between opposing points on the shoulders IE will burn opposing groove or furrows into the fiber cylinder l2 and fiber tube II, as indicated at in Figure 2 of the drawing. The thickness of the grooves 25 is greatly exaggerated in Figure 2 for purposes of illustration.

An arc will not usually be reestablished between the same pair of opposing points on the shoulders 56 of the electrodes M.

A very important feature of my invention is in having the shoulders l6 of the electrodes [4 spaced from the inside of the casing or tube ll, so as to leave expansion spaces therebetween. It has been found that on placing electrodes against an arrester housing, heavy arcs will puncture and burst the housing. My improved lightning arrester is capable of withstanding a number of heavy current arc discharges without failure by reason of the housing being punctured or broken adjacent to the electrodes.

Since certain changes can be made in the foregoing construction, and different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matters shown in the accompanying dawing or described hereinbefore shall be interpreted as illustrative and not in a limiting sense.-

I claim as my invention:

1. In a circuit interrupting device, in combination, a fiber housing, an imperforate fiber plug wall of said fiber plug and. the inside of said fiber housing providing a restricted arc passageway open at the ends, a pair of electrodes disposed at the opposite ends of said fiber plug, said electrodes being laterally spaced from the discharge path of gases from said restricted arc passageway so that an are established between said electrodes must make at least two changes in direction therebetween, and said are established between said electrodes being extinguished by a blast shooting out the open ends of said restricted arc passageway and cutting off said are where it turns at the open ends of said restricted arc passageway to meet said laterally spaced electrodes, said blast being created by gas evolution from said fiber housing and said fiber plug defining said restricted arc passageway.

3. A lightning arrester comprising, in combination, a fiber tube, a relatively short fiber block fitting closely within said fiber tube and leaving a narrow space therebetween, a pair of electrodes disposed against the opposite ends of said fiber block, the peripheries of said electrodes lying within the peripheries of the opposite ends of said fiber block, a pair of fiber sleeves extending outwardly from said pair of electrodes, the periphery of said fiber sleeves being substantially less than the internal periphery of said fiber tube so as to provide relatively wide annular spaces therebetween, means for closing the ends of said fiber tube having apertures therein for gas outlet, and terminal means individual to each of said electrodes.

4. A lightning arrester comprising, in combination, a fiber tube, a relatively short fiber block fitting closely within said fiber tube and leaving a narrow space therebetween, a pair of electrodes disposed against the oppositeends of said fiber block, the peripheries of said electrodes lying within the peripheries of the opposite ends of said fiber block, a pair of fiber sleeves extending outwardly from said .pair of electrodes, the periphery of said fiber sleeves being substantially less than the internal peripheryof said fibertube so as to provide relatively wide annular spaces therebetween, means for closing the ends of said fiber tube having apertures therein for gas'outlet, and terminal means individual to each of said electrodes, said narrow space between the inside of said fiber tube and the outside of said fiber block forming a restrictedare passageway opening at its ends into ,said, relatively wide annular spaces formedby said fiber sleeves and the outer portions of said fiber tube. a

5. A lightning arrester comprising, in combination, a cylindrical fiber tube, arelativelyv short fiber cylinder fitting closely within" said cylindricalfiber tube'and substantially midway between the ends ;thereof, a pair of? disc-shaped electrodes fitting against the end faces of said 'short fibercylinden'thelaterah edges of said electrodes lying a shortudistance :in. from the peripheries of the endfaces of saidshort fiber cylinder, a pair of cylindrical fibersleeves fitting on said electrodes and'extending outwardly therefrom toward the ends of said cylindrical fiber tube, said. cylindrical fiber sleeves being substantially less 'in' diameter than the inside of said cylindrical fiber tube so as to "leaver relatively wide annular spaces therebetween; apair of plugs closing the outer ends of said cylindrical fiber tube and having a plurality of. apertures therein for blastdischarge, and a pair of terminal posts extendingoutwardly from said electrodes through theendsof said cylindrical fiber tube, the narrow space between the outside of said short fiber cylinder and the inside of said cylindrical fiber tube providing a restricted arc passageway for an are established between said electrodes, the spacing of the lateral edges of said electrodes in from the peripheries of the end faces of said short fiber cylinder causing such anarc at its outer ends to take paths substantially normal to the axis of said cylindrical fiber tube whereby a blast created in' said restricted arc passageway shoots out of, the opposite ends thereof into said relatively wide annular spaces in a direction parallel? to the axis of said cylindrical tube to cut off said arc-at said sections of its path normal thereto. 6'. A circuit interrupting device comprising, in

combination, a pair of electrodes in spaced end to end relation between which an arc may be formed, means providing a restricted .arc passagewayv between said spaced electrodes in material adapted to evolve an arc extinguishing medium due to the heat of the arc, at least one end of said are pasageway being open and the electrode thereatbeing spaced laterally from the discharge path of said medium out, of said'arc passageway" whereby the are established between said electrodes is required to follow a path transverse to the path of said medium as it is discharged from said open end and is extended and extinguished thereby, conductor means extending from the electrode at said open end of said passageway, and insulating means surrounding said conductor means for a substantial distance from the electrode fromwhich' it extends. I

7. A circuit interrupting device comprising, in combination, a pair of electrodes in spaced end to vend'relation between which an arc may be formed, and means providing a restricted arc material adapted to evolve an arc extinguishing medium due to the heat of thearc, both ends of saidare passageway being open and the electrodes thereat being spaced laterally from the discharge path of said medium out of said are pasageway whereby the 'arcestablished between said electrodes is required to follow paths transverse to the path of said medium as it'is discharged from said open ends and is-extended and extinguished thereby. I

8. A circuit interrupting device comprising, in combination, a pair of electrodes in spaced end to end relation between which an arc may be formed, means providingfa restricted arc passageway between said spaced electrodes in material adapted to evolve an arc extinguishing medium, due to the heat of the arc, both ends of said arc passageway being open and the electrodes thereat being spaced laterally'from the discharge path of said medium out of said are passageway whereby the are established between said electrodes isreduired to follow paths transverse to the path of said medium as it is discharged from said open' ends and is extended and extinguished thereby, conductor means extending e'ndwise from each of said electrodes, and insulating means surrounding each conductor means for a substantial distance from the electrode from which it extends.

and means providing a restricted arc passageway between said spaced electrodes in material adapted to evolve an arc extinguishing medium due to the heat of the arc, both ends of said arc passageway being open and the electrodes thereat being spaced laterally from the discharge path of said i medium out of said are passageway whereby the arc established between said electrodes is required to follow paths transverse to the path of said medium as it is discharged from said open ends and is extended and extinguished thereby.

10. In a circuit interrupting device, in combination, a relatively long tubular housing, a relatively short imperforate plug fitting closely within said tubular housing intermediate its ends, said housing and plug being formed of insulating material capable of evolving an arc extinguishing medium due to the heat of an arc, electrodes at the ends of said imperforate plug between which an arc may be formed along the juxtaposed surfaces of said housing and plug, a conductor rod extending axially from each electrode out of its end of said housing; and a sleeve of insulating material extending outwardly from each electrode and spaced from the inner surface of said housing to provide therebetween a gas expansion space.

11. In a circuit interrupting device, in combination, a relatively long tubular housing, a relatively short imperforate plug fitting closely within said tubular housing intermediate its ends,-

said housing and plug being formed of insulating material capable of evolving an arc extinguishing medium due to the heat of an arc, electrodes at the ends ofrsaid imperforate plug between which an arc may be formed along the juxtaposed surfaces of said housing and plug, a conductor rod extending axially from each electrode out oi its end of said housing, and a sleeve of insulating material extending outwardly from each electrade and spaced from the inner surface of said housing to provide therebetween a gas expansion space, thegas expansion space at each end of said housing being vented to the atmosphere through a plurality of apertures.

12. In a lightning arrester, in combination a tubular housing, a plug within said tubular housing' spaced a substantial distance from at least one end thereof, said housing and plug being formed of insulating material capable of evolving an arc extinguishing medium due to the heat of an arc, electrodes at the ends of said plug between which an arc may be formed along the juxtaposed surfaces of said housing and plug, a conductor rod extending axially out of said one end of said housing from the adjacent" electrode therein, a sleeve of insulating material extending from abutting relation with said adjacent electrode and spaced from the inner surface of said housing to provide therebetween a gas expansion space, and clamp means at said one end of said housing abutting the adjacentend of said aaeasee sleeve and cooperating with said conductor rod to hold said sleeve in a predetermined position in said housing.

13. In a circuit interrupting device,vin combination, a relatively long tubular housing, a

trode out of its end of said housing, a sleeve of insulating material extending outwardly from abutting relation with each electrode and spaced from the inner surface of said housing to provide .therebetween a gas expanison space, the outer end of each sleeve being spaced inwardly from the adjacent end of said housing. and clamp means threaded interiorly of each end of said housing including means abutting the adjacent end of the sleeve therein for holding the various parts in positionin said. housing.

V CHARLES L. STROUP.