US2112841A - High voltage fusible cut-out - Google Patents

Description

April 5, 1938. G. L. HILL HIGH VOLTAGE FUSIBLE CUT-OUT s sheets-.sheet 1 Filed NOV. 2.6, 1934 o b. 1 1. 2 w n 11|1W1nlr r o l f 1 11 -1 mww 1N VEN TOR. :940170 MM.

A TTORN April 5, 1938. G. I HILL 2,112,841

` HIGH VOLTAGE FUSIBLE CUT-OUT Filed Nov. 26, 19344 s sheets-sheet 2 I V EN TOR.

AP 5, 1938. G. L.. HILL HIGH VOLTAGE FUSIBLE GUTOUT Filed Nov. 26, 1934 l5 Sheets-Sheet 3 13g' f- W ll| INVENTOR,

Patented Apr. 5, 1938 PATENT OFFICE 2,112,841 HIGH VOLTAGE FUSIBLE CUT- .application November 2 32 Claims.

This invention relates to a high voltage fusible cutout, and particularly to improvements in V an enclosed manually operated switch for ina fusible element stallation in subways, vaults, basements etc., which may be damp, or flooded with water at times, or installations where gases expelled might ignite explosive vapors and cause an explosion. l

All enclosed underground, high voltage, fus'- sible cutouts available and known at the present time use oil for an insulating medium and immersed in the oil for interrupting overcurrent't. The fuses used in enclosed, fusible cutouts are of three general types:

(a) Expulsion type, consisting of a long tube of insulating material, open at both ends, and having metal ferrules pressed onto the ends of the tube. A copper or alloy fuse elementpasses through the tube and is fastened to each ferrule. The fuse tube is clamped onto an operating arm which is used to engage or disengage the fuse with terminals inthe cutout. A cutout box is employed which is filled with oil, and this oil iills the fuse tube and entirely surrounds the fuse element.

(b) Spring actuated type in which the ruse element consists of an alloy strip with a strain wire, connected in parallel with the strip, to relieve the alloy strip of the tension from the spring.

spring are inserted in an insulating tube, with metal end caps, the element being fastened to one cap and the spring to the other. The tube is divided into two chambers by a center partition with a hole' The fuse element is disposed in one throush it.

` chamber, which becomes the explosion chamber,

and the spring is posed in the adjacent' chamber, which becomes the expansion chamber, expansion chamber being in turn vented to the inside of a cutout box. The cutout box, in turn. is iilled with oil and the oil fills the fuse tube and'entirely surrounds the fuse element.4

(c) Magnetic repulsion type in which the fuse element consists of a U-shaped member. fastened o`n the end of an insulated bayonet type plug which is inserted into the top of the cutout and then turned 90 for engaging or disengaging the fuse with terminals in the cutout box. This box volatilizes throughout its entire George Leslie l-lill, Oakland, Calif.

6, 1934, Seal N0. 754,747 (C1. 20o-120) is also filled with the fuse element.

All of the types (a, b and c) have very definite disadvantages. As an example, the fuse tube and fuse element of the expulsion type is ten or twelve inches long and the fuse element length on large currents. The arcenergy liberated is practically proportional to its length, so it may be seen that .the arc energy liberated is very high. The high pressure bursts the organic insulating tube and, in turn, burst the cutout ate over-currentsthe arc melts the -fuse element and follows back to the ferrule and burns the tube and in some cases causes failure.

v It has been found that the spring actuated type does not efiiciently utilize the oil in the explosion chamber for the extinction of the arc, and also that the spring actually retards and hinders the operation of the device on heavy over-currents, rather than being an aid in the operation.

The link of the magnetic repulsion type is blown under oil in the main chamber ofthe cutout box and on large over-currents very high pressures are set up of the order of six hundred to twelve hundred pounds per square inch. Such pressures may disastrous to the cutout box itself and to the supporting insulating members within the cutout box. currents, the magnetic repulsion actuates the side bands of the U so rapidly that they strike the wall of the cutout box and rebound to the center and re-establish the circuit.

The insulation on the operating mechanism for supporting the fuse of all the types have been made of various organic materials, such as wood and lmoulded or laminated balrelite.l It has been found that the small leakage currents over the surface of these insulators made of organic material carbonizes a path and frequently causes a power arc to start and thereby results in failure oi.' the device.

The object of the present invention is to provide an improved economical and efficient fuse device for the interruption of over-currents in an-electric circuit; to provide an improved ruse cartridge for insertion in a circuit-interrupting deviceand to form the wall of the explosion chamber of metal so that it may function both as a conductor for the circuitpassing through the interrupting device, and, further, to function as a reinforcing member to sustain the high pressures generated when the fuse blows on heavy over-currents; to provide an .improved and emoil and the oil entirely covers box. On modery Also on heavy overcient de-ionizing and cooling means for de-ionizing and cooling expelled gases, upon blowing of the fuse, whereby a dryA type fuse device may be used within an enclosed cutout box; to provide an improved fuse cartridge for insertion in a fuse device, which is adapted to employ oil as tridge of a type iilled with a4 dry granular or powder material.

Fig. 3 is a longitudinal section of a fuse cartridge of the oil or liquid lled type.

Fig. 4 is a detail view of the lower end of the fuse housing showing a modiiied form of the same.

Fig. 5 is a vertical, longitudinal section of the cut-out box, showing the fuse. deviceand switch mechanism mounted therein. v

Fig. 6 is a plan section, taken on line VI-VI of Fig.l

Fig. 7 is an end view of the cutout box.

Fig. 8 is a vertical cross section, taken on the line VIII-'VIII of Fig. 5.

Referring to the drawings in detail, and particularly. Figs. 1 and 2, 2 indicates an elongated, tubular member constructed of a suitable insulating material. ferred to as the fcartridge tube". Disposed within the cartridge tube is a tube 3. This tube is constructed of metal and serves the following functions: First, that of a conductor for the current passing through the fuse device; second, that of a receptacle for an arc extinguishing medium, such as indicated at 3a; and, third, that of a reinforcing member for the cartridge tube to sustain the high pressuredeveloped during the blowing of the fuse during the interruption of the circuit.

Disposed at opposite ends of the cartridge tube are bushings 4 and 4a, which are constructed of a suitable insulating material, and carried by the respective bushings are copper or similar terminal members 5 and 5a. To the inner ends are soldered, or otherwise secured, fuse elements 6 and 6a. 'I'he opposite ends of the tube 3 are tapered to form annular seats for the reception of the insulating bushings I and 4a. 'I'he inner ends of these bushings are similarly tapered, and each bushing carries a tapered sleeve or ferrule I and 1a which is pressed on or otherwise secured thereto. 'I'hese ferrules are in turn provided with an inwardly projecting tongue 8 and 8a, and the ends of the fuse elements 6 and 6a are soldered or otherwise secured thereto. 'I'he terminal member 5 terminates in a head 5b which is engaged There is a screw connection I0 between the cap and the cartridge tube 2; hence when the cap is applied, endwise pressure is exerted on the terminal member 5 and the insulating bushing in which it is mounted and the ferrule is thus pressed downwardly into the tapered end of thetube 3 so as to form a contact for the conduction of current from the cap 9, through the terminal 5 and the 'fuse 6,- to the tube 3.

The insulating bushing la is similarly tapered on its inner en d and carries a sleeve or ferrule 1a This tube will hereinafter be reprovided with an inwardly extending tongue 8a, to which the fuse element 6a is soldered, or otherwise secured. 'I'he lower end of the terminal member 5a is enlarged, as shown at 5b, and extends through a stuiling box containing a packing I I which is held in position by a nut I2, outside of which is applied a sealing medium I3. The insuthe tube 3, butit also forces the lower tapered downwardly against the ferrule 1a.

two functions: pigtail connection 2l; and, secondly, gas de-ionizing and cooling for instance, calcium carbonate, or any suitable actsfas a de-ionizing agent when proJected into the arc.

3 a modified minal member 28, having a cap 29 at its upper end, is screwed into the upper end of the bushing 2E. It carries a fuse element 30 and this is soldered, or otherwise connected, with a metal lbushing 3I, screwed or otherwise secured in lthe nected with a exible conductor or pigtail 2Ia, similar to that disclosed in Figs. 1 and 2.

The diaphragm, indicated at 34, serves two main functions: First, that of a seal to retain the oil or other arc extinguishing substance with which the chamber, indicated at 38, is lled; and, secondly, it serves as a fuse. The diaphragm prevents leakage of the arc extinguishing substance employed around the terminal member 36 and by applying a suitable lacquer to the threads when the bushing 26 is applied leakage through that end of the fuse cartridge is avoided.

The fuse cartridge shown in Fig. 2, as previouslydescribed, is designed for insertion in the fuse housing, such as shown in Fig. 1. rI'he wet or liquid type of cartridge shown in Fig. 3 is similarly suited for insertion in the housing I5, but the gas de-ionizing and cooling device, indicated at 22, will in that instance be removed and it will be replaced by a slotted cap, such as shown at 22al (see Fig. 4). The gas de-ionizing and cooling device, indicated at 22, is similar to the one shown in my co-pending applicationentitled High tension fuse, iiledJanuary 12, 1931,Serial Number 508,029, but is an improvement thereon.

In my earlier disclosure of the device above referred to, a single chamber was employed, into which the gases from the cartridge discharge. 'Ihe chamber was perforated and steel wool or a similar cooling medium was placed within the chamber. In the present instance (see Fig. 1) a central chamber 40 is provided and surrounding the same is an annular chamber 4|. Two concentric tubular walls are'provided, as indicated at 42 and 43. These are both perforated and the space between them is filled with steel wool or a similar cooling medium, the cooling medium being retained in the annular chamber by a bottom plate 44.

By this construction the hot gases discharged from the fuse cartridge are-permitted to rapidly expand. This, obviously, aids in the cooling of the gases and as the vgases also have to pass through the cooling medium in the annular chamber 4I further and rapid cooling of the gases is insured. If desired, the wall 43 may be used without any perforations, thus making an entirely closed in device.

While the dry type of fuse cartridge and the housing provided for it and shown -in Fig. l may be placed wherever desired, I wish to emphasize the fact that itmay also be placed in confined spaces, such as cutout boxes, and the like. The liquid or wet type of fuse cartridge, shown in Fig. 3, is one intended for installation in a cutout box, and its use will hereinafter be described. For the purpose of describing the manner in which a fuse device of this character may be installed in a cutout box, reference will be made to Figs; 5 to 8, inclusive. In these gures the numeral 5I) indicates a form of cutout box which is provided wtih two cables entering the cutout box through insulating bushings 5I'-5I. Passing through the `bushings and suitably secured therein are terminal studs 52, to which are fastened spring clip contacts 53. Swfitchblades 54 are adapted to be inserted between the contacts and they are secured to clamping members 65 which are, in turn, secured to and supported by porcelain insulatorsi, these being secured, in

turn, to an'oper'ating rod orshaft y51 by y.means Y of clamps 58. Thek switch blades 641mm a part of the clampingmembers,6 5 they te* fas-l means. The operating shaft 51 is supported in bearings, as shown, and one end extends through the end of the cutout box, the extending end being provided with an operating handle 59, on which is mounted a knob 60. The handle swings over a quadrant 6I and slots or depressions may be formed therein to retain the switch arm in different positions.

The housing IliA containing a' fuse cartridge,l

whether it be of the dry or liquid type, is best shown in Figs. 6 and 8. It is secured at opposite ends by the clamping members 55 and as these surround the ferrules I6 and I9, a circuit through the switch and the fuse device is established.

To place the device inservice, the voperation will be as follows: The handle 59 is moved to the re-fuse position on the quadrant 6I and the fuse housing I5, containing a fuse cartridge, is inserted in the clamps 55 and-secured therein and the handle is 'then moved to the open position. If a dry type of fuse cartridge is to be inserted the gas de-ionizing and cooling device, shown at 22, will be applied before the fuse cartridge isinserted. After that it will only be necessary to apply a cover on the cutout 50 and to clamp it down by the thumb-screws shown, a packing being interposed between the box and the cover to render the box watertight.

After the cover has been securely fastened, the handle 59 is moved to closed position. This causes engagement of the switch blades 54 with the spring contacts 53, thus placing the fuse in the electric circuit.

When an over-current occurs, the fuse element 6 will melt or blow first as it is purposely made smaller than'the element 6a. The heat from the resultant arc will decompose the surrounding arc extinguishing substance and thereby generate a gas which will build up a high pressure in the chamber. When the pressure has reached a predetermined value, the terminal member 5a starts to move outwardly and places a tension on the fuse element 6a. When the tension exceeds the strength of the fuse element 6a, which, by the way, has already been weakened by the heat produced by the over-current, it is easily pulled apart, causing a secondary arc as the terminal 5a is expelled outwardly through the tube 4a. The tubes 4'and 4a, may be made of a material, such as horn fibre, ich will also decompose from the heat of the arcs and give off a de-ionizing gas.

The instant theI secondary arc is established in the passage of the bushing 4a, the gases previously generated and the arc extinguishing substance are blasted into it at a high velocity and in a turbulent manner. This causes a rapid deionizing action to take place and interrupts the circuit. 'I'he gas blast from the chamber will expel all the ionized products resulting from the arcs and leave a clean de-ionized path in the bushing 4a.

When the terminal member 5a is expelled from the fuse cartridge the flexible conductor or pigtail 2| is forced downwardly into the chamber 40 where it will pile up and introduce an insulated path between the end of the fuse cartridge and the interior of the ferrule' I9. The hot ionized gases expelled from the central passage in the bushing 4a will also pass into the chamber 40 and then through the perforated cylindrical wall 43 into the annular chamber 4I and then through the perforations in the outer wall 43. During this ow the gases expand and cool and Cil are finally released into the space Within the cutout box.

Tests and experiments have been conducted which show that the expulsion and cooling of the gases'are so thorough that they may be successfully released within an enclosed metal cutout box, such as here illustrated, making such boxes available for underground, subway or basement service. However, tests have also shown that the holes in wall 43 may `be eliminated and the material in chamber 4i will continue to act as a cooling medium forthe gases.

On large over-currents both fuse elements 6 and 6a will blow or melt, but due to the fact that the element 6 is smaller than the element 6a an increment of time will always exist between the blowing of the two fusible elements, the increment decreasing as the current increases but the blowing of the two elements will never become simultaneous, so that there will always be a pressure generated by the primary arc at 6 before the aro starts at 6a, this pressure being utilized to extinguish the second arc.

The secondary arc at 6a, while it persists, will also generate a gas by decomposing the surrounding arc extinguishing substance. This gas, due to the fact that the arc at 5a starts at a later period of time than the arc at 6, will be at a lower pressure than the gas from the arc at 6 and will be blasted back into the arc stream at 6a, resulting in a most efiicient and quick means of interrupting the electric circuit.

ln the ordinary operation of a switch, when the box is not lled with an oil, such as shown in Figs. 5 to 8, inclusive, it is obvious that excessive arcing will take place between the blades 54 and the spring contacts 53 whenever the switch is opened while carrying a load current. To reduce such a tendency to arc, a shunt circuit is here illustrated. This shunt circuit is established by providing a pair of auxiliary' switch blades 7U, which engage spring contacts il. These contacts are fastened to a casting 12 by means of screws, as shown. A suitable resistance material 13 is clamped between the casting l2 and a bracket ld. The object of this auxiliary circuit is to aid in preventing excessive arcing when the cutout is used as a disconnecting switch without oil in the cutout box. The blade lll and contact ll are designed to remain in Contact after the blades 54 and contacts 53 have parted, thus shunting the circuit from the main operating blades and contacts through the resistance material i3 and the blades and contacts, indicated at 'l0 and 1l. The resistance material 13 employed in this instance may have a characteristic similar to the inorganic resistance material used in lightning arresters; that is, it is substantially an insulator at a low voltage and a conductor at a high voltage. The resistance material referred to is a dense synthetic granular compound of a refractory and a ceramic nature combined into a mass under high temperature. It is usually sold under the trade names of Thyrite, Antovalve and Granulon.

When the voltage rises to its full value during an alternating current 'zero, while an arc is drawn, between 54 and 53, the material "i3 will `become a conductor andl shunt the current around through the bracket i4, the resistance material 13, castings l2, contacts 7i and blades l0. 'Ihe arc will then break easily-between the contacts 53 and blades 54,` and due to the additional resistance interposed in the shunt circuit, the arc will also break easily between the contacts 'H and the blades 10, thus interrupting the circuit.

The cutout box, which has been described up to this point in conjunction with the dry type of cartridge fuse, has not been filled with an insulating oil, but above certain operating voltages the cutout box may be filled with oil and the dry type fuse cartridge is replaced with a fuse cartridge, utilizing oil, of the type illustrated in Fig. 3. The similarity in construction and operation between the dry type fuse cartridge and the liquid or oil type fuse cartridge is readily observed. It will be noted that an insulating tube, similar to that shown at 2 (see Fig. 2), is not employed as it has been found by tests to be unnecessary, due to the fact that the oil surrounds the fuse cartridge tube when inserted in the housing tube l5 and thereby provides suillcient insulation. 'I'he housing tube I5 is, accordingly, used for both the dry and liquid type of fuse cartridge, and the only change necessary, when employing a liquid type of fuse cartridge, is to remove the gas de-ionizing and cooling member, indicated at 22, and replace it with the slotted or perforated cap, shown at 22a in Fig. 4. This cap is nothing more nor less than a venting cap and it is employed when the cutout box is iilled with oil. This cap serves the triple purpose: First, that of clamping the divided ends of the pigtail or flexible conductor 2i to the ferrule i9; secondly, that of venting the housing tube I5; and, third, that of catching the expelled' parts so as to prevent them from causing an electrical contact with the metal parts of the cutout box.

Referring to the liquid or oil type of fuse cartridge shown in Fig. 3, it will be understood that the chamber 38 is lled with oil or other suitable arc extinguishing substance and that the oil is retained by the diaphragm 34 and by applying a lacquer or similar medium to the threads at the opposite end of the fuse cartridge.

In operation, when a predetermined overcurrent occurs, the fuse melts or blows and establishes an arc which decomposes the surrounding oil, resulting in a pressure being built up in the chamber 38. The pressure, after reaching a predetermined value, will rupture the diaphragm 34 and establish a second arc in the orifice formed in the bushing 21. A blast of oil and gas into this second arc will interrupt the high voltage circuit in a quick and efficient manner similar to the operation of the dry tube previously described.

Where the liquid or wet type of fuse cartridge is employed, the cutout box will preferably be filled with oil so that the fuse device, together with the switch mechanism employed, will be completely submerged. In that case the circuit shunting device may be entirely eliminated as the switch blades and flexible contacts will be submerged in the oil and the arc formed when operating as a disconnect switch will be quenched thereby.

While certain features of the present invention are more or less specifically described, I wish it understood that various changes may be resorted to within the scope of the appended claims. Similarly, that the materials and finish of the several parts employed may be such as the manufacturer may decide, or varying conditions or uses may demand.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a circuit interrupting device, a member 75 having a chamberformed therein, a pair of terminal connectors, one at each end and insulated from the member, a circuit interrupting device disposed interior of the member between the Vterminal connectors and forming a conductor between one terminal connector and said member, said chamber forming a receptacle for an arc extinguishing medium, and said member forming a conductor between the other terminal connector and the interrupting device and sustaining the pressure produced during interruption of the circuit.

2. In a circuit interrupting device an elongated member having a chamberformedtherein, said chamber forming a receptacle for an arc extinguishing medium, means at opposite ends of the chamber for forming successive arcs, said elongated member forming a conductor between the arc forming means and sustaining the pressure produced by the arc forming means, a pair of terminal connectors, one at each end of the elongated member and insulated therefrom, and a connection' between each terminal connector and an adjacent arc forming means.

3. In a circuit interrupting device an elongated member having a chamber formed therein, said chamber forming a receptacle for an arc extinguishing medium, means at one end of the chamber for forming an arc, a terminal connector at each end of the elongated member and insulated therefrom, a connector between one terminal connector and the arc forming means, a connector between the other terminal connector and the adjacent end of the elongated member, said member forming a conductor between thelast-named connection and the arc forming member and sustaining the pressure produced by the arc forming means.

4. In a circuit interrupting device a cutout box, a switch within the box having a pair of stationary and a pair of movable terminals, a fuse controlled circuit interrupting device connected between the movable terminals of the switch, metallic means for de-ionizng of gases discharging by the blowing of a fuse, and means for establishing a shunt circuit for preventing excessive arcing when disengaging the movable terminals of the switch with relation to the stationary terminals.

5. In a circuit interrupting device a cutout box, a switch within Ithe box having a pair of stationary and a pair of movable terminals, a fuse controlled circuit interrupting device connected between the movable terminals of the switch, means for momentarily shunting the circuit when disengaging the terminals of the switch, and a reslstance material in said shunt circuit, said material having the characteristic of becoming a relatively good conductor at an alternating current zero when an arc is drawn between the switch contacts and thereby shunt the current through the resistance material and reduce the arcing between the switch contacts.

6. In a circuit interrupting device, a metallic member within the device and having a chamber formed therein, and means in the chamber to form two arcs, said metallic chamber adapted to sustain the pressure generated by said arcs and to act as a conductor between the arcs and an arc extinguishing substance surrounding each arc.

1. In a circuit interrupting device, a metallic member withih the device having a chamber formed therein, and means in the chamberfor establishing a preliminary arc and thereafter a second arc. said metallic member acting as a conductor between the arcs and an arc extinguishing substance surrounding each arc.

8. In a circuit interrupting device, a metallic member within the device having a chamber formed therein, and a compound fuse element having a small current carrying capacity section and a greater current carrying capacity section located within the chamber, said metallic member acting as a conductor between the two fuse sections.V

9. In a circuit interrupting device, a metallic member within the device having a chamber formed therein, and a compound fuse element having a small current carrying capacity section and a greater current carrying capacity section locatedl within the chamber, said metallic member acting as a conductor between the two fuse sections, said fuse element of greater current carrying capacity forming a seal for one end of the chamber.

10. In a circuit interrupting device, a metallic member, within the device having a chamber formed therein, means in the chamber for establishing a preliminary arc and thereafter a second arc, said metallic member acting as a conductor between the arcs, and an arc extinguishing substance in the chamber and surrounding both arcs, said metallic member sustaining the pressure generated by the arcs, said arc extinguishing substance being blasted into the second arc by the pressure generated by the preliminary arc.

11. In a circuit interrupting device, a metallic member within the device having a chamber formed therein', a compoundv fuse element having `a small current carrying capacity section and a as a conductor between the two fuse sections, and

an arc extinguishing substance in the chamber and said metallic member sustaining the pressure generated within the chamber, the energy generated during the blowing of the small fuse section being utilized to aid in establishing an arc in the fuse of greater current carrying section.

12. In a circuit interrupting device, a metallic member within the device having a chamber formed therein, a compound fuse element having a small current carrying capacity section and a greater current carrying capacity section located within the chamber, said metallic member acting as a conductor between the two fuse sections, and an arc extinguishing substance in the chamber and said metallic member sustaining the pressure generated within the chamber, the energy generated during the blowing of the small current carrying section being utilized to aid in extinguishing, the arc formed in the fuse of greater current carrying section.

13. In a circuit interrupting device of the character described an elongated metallic tubular member having a tapered seat formed at each end, a tapering insulator insertable and engageable with each seat, a terminal member carriedy 15. In a circuit interrupting device of the character described an elongated metallic tubular member having a tapered seat formed at each end, a tapering insulator insertable and engageable with each seat, a terminal member carried by each insulator, one of said terminal members being expellable, and a fuse device connecty ing each terminal member with the metallic tube. 16. In a circuit interrupting device of the character described an elongated metallic tubular member having a tapered seat formed at' character described an elongated metallic tubular member having annular shoulders formed thereon adjacent opposite ends, fuse plugs insertable in the opposite ends of the tube, each plug having a contact end engageable with the adjacent shoulders, and a terminal member carried by each fuse plug to establish an electric circuit.

18. In a circuit interrupting device of the character described an elongated metallic tubular member having annular shoulders formed thereon ladjacent opposite ends, fuse plugs insertable in the opposite ends of the tube, each plug having a contact end engageable with the adjacent shoulders, a terminal member carried by each fuse plug to establish an electric circuit, one ci said annular shoulders having an annular tapering contracted passage formed therein to form a discharge ori'lce'for the discharge of gases generated during blowing of the fuse at high velocity.

19. 'Ihe combination with the expulsion end of a* fuse of the character described, of a deionizing device comprising a container consisting of an inner and an outer housing, said housings being spaced apart and the walls of said housings being perforated and a de-ionizing medium disposed in the space formed between the housings.

20. The combination with an expulsion end of a fuse of the character described, of a deionizing device comprising a container consisting of an inner and an outer housing, said housings being spaced apart and the walls of Said housings being perforated, and a metallic de-ionizing medium disposed in the space formed between the housings.

21. In a high voltage fuse, an expulsion tube having metallic end terminals, a re-ll cartridge for insertion in the tube, said cartridge comprising a` metallic member Within the cartridge, said member having a chamber formed therein, and means in the chamber to form an arc, said metallic member adapted to sustain the pressure generated by said arc and to act as a conductor between said arc and the terminal.

22. In a high Voltage fuse, an expulsion tub-e having metallic end terminals, a re-ll cartridge for insertion in the tube, said cartridge comprising a metallic member within the cartridge having a chamber formed therein, means in the chamber for establishing a preliminary arc and thereafter a second arc, said metallic member acting as a conductor between the arc and an arc extinguishing substance in the chamber and said metallic member sustaining the pressure generated by the arcs.

23. In an enclosed high voltage cutout box, electric terminals within the box, an expulsion fuse comprising an insulating tube, a fuse element within the tube, a metallic de-ionizing and cooling means attached to the end of the expulsion tube, and means for connecting the expulsion fuse to the terminals within the box.

2d. In a high voltage fuse, an expulsion tube having metal end terminals, a re-ll cartridge for insertion in the tube, said re-flll comprising a metallic tube having a chamber formed therein, means in the chamber for establishing an arc, and means in the chamber for interrupting the arc after it is established.

25. In a circuit interrupting device an enclosed cutout box, a switch Within the box connected with a source of currentsupply, a fuse-controlled circuit interrupting device connected in the circuit and disposed within the box, and means for de-ionizing gases discharging by the blowing of the fuse, said means comprising a container consisting of an inner and an outer housing, said housings being spaced apart and the walls of said housings being perforated, and a de-ionizing medium disposed in the space formed between the housings.

26. In a circuit interrupting device an enclosed cutout box, a switch within the box connected with a source of current supply, a fuse-controlled circuit interrupting device connected in the circuit and disposed within the box, and means for de-ionizing gases discharging by the blowing of the fuse, said means comprising a container consisting of an inner and an outer housing, said housings being spaced apart and the walls of said housings being perforated, and a metallic de-ionizing medium disposed in the space formed between the housings` 27. In a circuit interrupting device an enclosed cutout box, a switch within the box connected with a source of current supply, a fusecontrolled circuit interrupting device connected in the circuit and disposed within the box, means for momentarily shunting the circuit when disengaging the terminals of the switch, a resistance material in said shunt circuit, said material having the characteristics of becoming a relatively good conductor at a high voltage and a poor conductor at a relatively low voltage when an arc is drawn between the switch contacts, and

thereby shunt the current through the resistance material and reduce the arcing between the switch contacts.

28. In a circuit interrupting device an enclosed cutout box, a switch Within the box connected to a source of current supply, a fusecontrolled circuit interrupting device connected in the circuit and disposed within the box, metallic means for de-ionizing gases discharging by the blowing of the fuse, and means for establishing a shunt circuit for preventing excessive arcing when disengaging the switch.

29. In a circuit interrupting device a member having a chamber formed therein, a pair of terminal connectors, a circuit interrupting device between the terminal connectors, said chamber forming a receptacle for an arc extinguishing medium, and said member forming a conductor between the terminal connectors and the interrupting device and sustaining the pressure produced during interruption of the circuit.

30. In a circuit interrupting device an elongated member having a chamber formed therein, said chamber forming a receptacle for an arc extinguishing medium, means at opposite ends of the chamber for forming successive arcs, said elongated member forming a conductor between the arc forming means and sustaining the pressure produced by the arc forming means.

I 31. In a circuit interrupting device, a metallic member within the device, said member having a chamber formed therein, and means in 'the chamber to form an arc, said metallic member adapted to 'sustain the pressure generated by said arc and to act as a. conductor between said arc and a terminal.

32. In a circuit interrupting device, a metallic member within the device, said member having a chamber formed therein, means in the chamber to form an arc, said metallic member adapted to sustain the pressure generated by said arc and to act as a conductor between said arc and a terminal, and an arc extinguishing substance in the chamber. A

GEORGE LESLIE HILL.

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