US2343422A - Gas blast circuit interrupter - Google Patents

Description

March 7, 1944. H. L RAwLlNs GAS; BLAST CIRCUIT INTERRUPTER Filed Feb. 20, 1940 2 Sheets-Sheet l yPatented Mar. 7, 1944 amaze l ons sms'r cmcuir Mmmm Herbert L. Rawlins. Wilkinsbnrg. Pa., assignmto Westinghouse Electric Manufacturing Coinpany, East Pittsburgh. Pa.. a corporation of Pennsylvania Application Femm zo, im. sei-iai No. nasse :s claim. (ci. zoo-1w- My invention relates generally to electric circuit interrupting devices. and more particularly to such devices which are capable of automatically interrupting an electric circuit upon the passage therethrough of currents above a predetermined value. and to the manner of extinguishing electric arcs formed thereby.

In a circuit interrupter where it is necessary to interrupt currents o! dii'terent magnitudes, it is desirable to provide a single means tor extinguishing the arcs formed. which will operate in a'quick and emcient manner irrespective of the current magnitude of the arc. Electric arcs may be efilciently extinguished by the use of a blast of cool, un-ionized gas played throughv the arc stream to cool and deionize the same. Such a gas blast may be derived from an independent source of compressed gas. or it may be generated by the are itself by. its action on a gas evolving material. To obtain arc extinguishing gas from an outside source involves in addition to the lnterrupter and outside source, suitable connections therebetween, constructed so as to be automatically operable to deliver gas when an arc lis struck. Self-generated gas interrupters eliminate such additional structure and attendant complexities, but the quantity of gas generated is usually dependent upon the current magnitude of the arc.

One object of my invention, therefore, is to provide a circuit interrupter of the self-generated gasblast type which is capable oi' producing a relatively large quantity' of cool, unionized arc extinguishing gas independently of the current magnitude of the arc formed.

Another object of my invention is to provide in a circuit interrupter of the gas blast type, a novel arcing chamber construction. having means for advantageously directing arc extinguishing gas through the arc.

Another object of my invention is to provide a circuit interruptor having incorporated therein a potential source of arc extinguishing gas which is released in response to the striking of an arc, and wherein the amount of such gas released is independent of the current magnitude of the arc formed.

Another object oi' my invention is to provide a novel form of fuse wherein a fusible element acts to release a supply of arc extinguishing gas which, in turn, operates to open separable contacts and extinguish the arc formed at said contacts.

Another object oi my invention is to provide a novel form o! circuit uiterrupter having separable contacts. with a .Supply oi' arc exgaslnamannersuchthatthegas is operable to separate said contacts and extinguish the arc formed.

Another obiect ot my invention is to provide a' t inten-opter or the type dcsibed emin a fuse which is and arranged so as to automatically drop out ot its associated circuit whenv the tuse blows.

Still another object oi my invention is to provide a .totally enclosed fuse of the type described which is so constructed and arranged as to automatically drop out of its associatd circuit in response to blowing oi' the fuse.

A further object oi my invention is to provide a circuit interrupter having means associated therewith for producing relatively large quantities of gas by chemical action, together" with means for cooling such gas and directing it' ing novel gas generating means associated i therewith in the form of a replaceable unit.

Another object of my invention is to provide a fuse construction having s. novel replaceable refill unit construction which includes fusible means and gas generating means.

' These and other objects of my invention will become more apparent upon consideration of the following specication of preferred embodiments thereof taken in connection with the attached drawings, in which:

Figure 1 is a longitudinal section through a fuse illustrating one embodiment of my invention;

Fig. 2 is a partial longitudinal sectional view of a fuse illustrating another embodiment of my invention;

Fig. 3 is a view similar to Fig. 2 and illustrating a still further embodiment oi' my invention;

Fig. 4 is a sectional view similarto Figs. 2 and 3 and illustrating another modiiication oi' my invention;

Fig. 5 is a side view illustrating a fuse which may be constructed in accordance with my invention and one manner of mounting the same in engagement with a pair o! line contacts:

Fig. 6 is a partial, central, longitudinal crosssection view of the lower portion of a fuse and a part of its mounting means, and illustrating a modification of the mounting illustrated in 1538.52

Fig. 7 is a view similar to Fig. 6 showing a further modified form of fuse mounting means.

Referring to the drawings, in Figure 1 I have shown a fuse comprising an. insulating tube 2 which may be of fiber, porcelain, glass or any other insulating material. The tube 2 is provided with upper and lower terminal ferrules 4 and I, respectiveLv, threadedly engaged with the threaded ends of fuse tube 2. 'I'he upper fuse terminal ferrule 4 is in the form of a cap prdvided with a central opening l for receiving a portion of a fuse refill unit for securing the same in position in the fuse tube 2. 'I'he fuse illustrated in Fig. 1 is constructed with a readily replaceable refill unit which may be easily and quickly renewed when the fuse blows. The refill unit includes a tubular metallic member I having an interiorly threaded upper end portion forming in the member I0, a shoulder I2 on which is seated a metallic supporting disk Il of conducting material. The disk I4 is secured in position in the tubular member I0 by means of an end closure plug I6 threadedly engaged in the upper end of the tubular member III, and

` having a 'reduced upwardly projecting portion I6 extending through the aperture l in end terminal cap 4 of fuse tube 2, which portion is threaded to cooperate with the clamping member I1 which acts to secure the refill unit in operative position within fuse tube 2.

The lower portion of the tubular member III of the refill unit is reduced as at I8, to provide a shoulder 2li upon which is seated a perforated partition member 22. The lower reduced end I8 of the tubular member I0 is exteriorly threaded for cooperation with a tubular insulating throat member 24, which may be of-any desired insulating material such, for example, as fiber or a molded insulating material. As shown in Fig. 1, the tubular throat member 24 is provided with a substantially cylindrical bore 26 adjacent to and forming an extension of the bore of the reduced end Il of tubular member III, and with an outwardly flaring exit portion 28. An insulating tube 30, of fiber or the like, is positioned in a central aperture through the perforated end closure disk 22 and extends upwardly within the tubular member Il to a position spaced fromthe supporting disk I4 for receiving a high resistance fusible wire 32 therein. The wire 32, which may be of any desired high resistance fusible alloy, such as nickel-chromium alloy or the like, has its upper end anchored to the supporting disk I4 in any desired manner, as by being soldered within an aperture in the disk as shown.

and its lower end is secured in a conducting sleeve 34 as by soldering or the like, andthe sleeve is in turn connected to the upper end of a flexible conductor 36. 'I'he conductor 36 may be of any suitable flexible conducting material preferably of a stranded copper wire construction.

The conductor 36 extends downwardly through the insulating fuse tube 2 and through an aperture provided in an end cap 36 threadedly mounted on the lower fuse terminal ferruie 6. The flexible conductor 36 is then bent about the end cap 36 to be secured to the end ferrule 6 as by the thumb nut 42.

Within the upper portion of the tubular member I0 of the refill unit, and in engagement with the high resistance fusible wire 32, I provide gas generating material 44 which may be gun pow ins, or the like.

der, gun cotton, or any other desired type of explosive or semi-explosive material, or highly combustible material which is adapted to evolve relatively large quantities of hot gas upon combustion. In the lower portion of the tubular member I0 and separated from the gas generating material 44 as by a metallic screen 48, I provide cooling means 46, which may be in the form of metal shavings, or a gas evolving material which is capable of evolving relatively cool un-ionized gases when subjected to heat, such, for example, as boric acid, fiber, synthetic res- If desired, of course, the cooling medium 46 may comprise a mixture of metal shavings and such gas evolving material.

The sleeve 34 which is secured to the upper end of the flexible conductor 26 is also connected to the reduced portion I8 of the tubular member II) of the refill unit, by means of a short section 50 of a calibrated relatively low resistance fusible wire.

The circuit through the fuse extends from the upper terminal ferrule 4 and clamping disk I1, through the end closure plug I6, and then in parallel circuits, one of which extends through the tubular member IU to the reduced portion I3 thereof, and fuse link 50, to the flexible conductor 36 and the lower terminal ferrule 6. The high resistance fuse wire 32 is in parallel with the fuse link 5D and with the tubular member IIJ, since it is electrically connected between end closure plug I6 b y way of the supporting disk I4 to the sleeve 34 on the upper end of flexible conductor 36. Thus it is seen that I have provided two fusible wires in parallel; however, inasmuch as the wire 32 is of relatively high resistance and the fusible section 5U is of relatively low resistance, the greater part of the current through the fuse will pass through fusible section 5D around high resistance fuse wire 32.

In operation, when the current through the` fuse exceeds a value predetermined by the short fusible section 50, this fusible section will melt and the current through the fuse will be transferred through the high resistance fusible wire 32. This, in turn, will melt practically instantaneously following the fusion of the fusible section 50, and heat generated thereby will ignite the gas generating material 44 in the upper end of the tubular member I0. Gases which are generated by explosive or semi-explosive material usually have a relatively high temperature and therefore in passing downwardly through the tubular member I0 these gases will be cooled by the cooling material 46 in the lower portion of the tubular member I0 and escape through the perforated end' closure disk 22 into the passage 26 and thence downwardly in the fuse tube. material is employed, the heat of combustion of material 44 and the heat contained in the hot gases evolved will cause evolution of aro extinguishing gas from such material 46 which will also pass down through perforated closure disk 22. vAfter the high resistance fuse wire 32 has blown the arc will obviously be reestablished between the sleeve 34 on the upper end of the flexible conductor 36 and the closely adjacent portion I8 of the tubular member I0. The gases then in passing downwardly through the fuse will pass through the arc and tend to expel the upper end of the flexible conductor 3E from the passage 26 in the insulating member 24. It should be noted that the reduced lower end I8 of the tubular member Ill, together with the insulating Where cooling means 46 of gas evolving member 24, form a. restricted or Venturi passage therethrough. This is particularly advantageous since the arc is struck substantially in the throat portion 28 of the Venturi passage where the highest gas pressure will be concentrated to l quickly blow out the arc and expel the upper end sleeve of the flexible conductor 38 from proximity to the tubular member I8. This action will extinguish the arc by supplying relatively cool unionized gas in a blast through the arc, and by drawing out the arc, to thereby increase the arc voltage, by blowing the sleeve 34 on the flexible conductor 38 downwardly away from the tubular extension I8. A

In connection with the blowing of the fuse shown ,in Fig. 1, it should be. noted that three successive arcs are struck, and that the current is successively shifted from one path through the fuse to another, and then back to the first path.

This occurs as follows: When the fusible' section 58 blows, the main portion of the current flowing through the fuse is suddenly transferred to the high resistance fusible wire 32 and no current flows through the shunt path provided by the tubular member I8 and fusible section 58 which has, of course, been blown. Substantially instantaneously thereafter the high resistance fusible wire 32 blows and the current is then shifted back to the shunt path provided by the tubular member III through thereduced lower end I8 thereof and across the gap to the sleeve 34 on the upper end of the flexible conductor 38. It should be noted that the high resistance fusible wire 32 acts tol relieve the strain on the short fusible section 58 as well as serving to ignite the gas generating material 44 with which it is inl contact.

After the fuse is blown, it is possible to easily refill the fuse by removing theA lower end cap 38 and releasing the flexible conductor 38 from the thumb screw 42, andthen unscre'wing the clamping disk Il, whereupon the entire refill unit comprising all the parts supported within the fuse tube 2 may slide out of the lower end of the tube. In inserting a new refill unit, this may be merely slid into the lower end of the tube until the proiromthe aperture 8 in the upper fuse terminal cap 4 whereupon the clamping disk I1 may be secured to the projection I5, and the lower fuse cap 88 threaded over the flexible conductor 88 and s'crewedinto position, and the flexible conductor 38 may then be clamped to the lower fuse ferrule 8 by the thumb nut 42.

The fuse illustrated in Fig. l is substantially totally enclosed and the lower portion of the fuse tube 2 is utilized as an expansion chamber for- However,`if desired the lower end` restricted portion, which may be formed by an insert 88 threadedly engaged in the insulating throat member 84. The inner contour of the passage through th'e throat member 84 then flares outwardly as at 88, to provide as in the previously described embodiment, a restriction in the gas passageway to form a substantial Venturi passage therethrough. The inset 88 provided for the insulating throat member 84 may be ofany desired material, preferably some heat resistant material such as metal or an insulation material a short calibrated fusible section 88. The elec'- jectlng portion I on the closure disk I8 projects The tubular member lo in this embodiment or my invention is generally similar to that previously described, differing therefrom in that it is provided witth an integral perforated bottom closure 52, having an integral, depending, centrally positioned electrode 82 extending outwardly of the lower end of the reduced portion I8 of the tubular trode 82 is also provided with a central,' longitudinally extending bore in which is received an insulating tube 84 similar to the tube 88 described in connection with Fig. 1, for receiving a relatively high resistance fusible strain wire 88 similar to the wire 82 disclosedin connection with the embodiment of my invention shown in Fig; 1. The tubular member I8 in this embodiment of my invention contains gas generating material 44 and cooling means 48 as in the previously described embodiment.

The operation of the fuse shown in Fig. 2` is much like that described in connection with the fuse shown in Fig. 1and hence willnot be repeated in great detail. TheI main difference in operation of this fuse resides' in the fact that the gas `blast is directed peripherally around the arcing electrode 82. The arc will be drawn, in this embodiment of my invention, between the electrode 82 and the sleeve 34 on the flexible, conductor 38. Hence the gases will be directed around the electrode 82 and then converge through the restricted portion of the arc e provided by the liner 88, and then may expand outwardly in the flared portion 88 of the passage.

The gas passage in this embodiment of my invention, it will be noted. may be termed a Venturi passage as in the embodiment illustrated in Fig. i. It should be noted that the gases passing through the varc between the terminal 82 and the sleeve 34 will be crowded together into a high' pressure region provided by the restricted lining 88. This will also tend to reduce the cross-section of the arc and thereby aid in extinguishing the same. `The order of blowing of the fusible section 88, and the high resistance fusible wire 88, and the final striking of an arc between the -terminal 82 and sleeve 34, is the same as that previously described in connection with the embodiment shown in Fig. 1. Similarly, this fuse may be refilled in exactly the same manner as that previously described. l

In Fig. 3 I have shown a form of fuse where the fusible elements proper ,are remote from thepoint at which the. arc is finally struck and extinguished, and wherein the gases generated also operate to separate the arcing terminals to draw out the arc. Many of the parts of the fuse shown in Fig. 3 are similar to those described in connection with Figs. 1 and 2, and hence like reference numerals will be used here to designate like parts. In' this form vof fuse I have provided, as shown in Fig. 3, a tubular metallic member I8 4 However, I have provided the upper end of the tubular member i8 with an end closure plug 88 having a centrally interiorly threaded aperture therein, in which is secured an insulating screw 18 for securing the end fitting 12 thereto in insulating relation. An insulating washer 14 is provided between the fitting 12 and the closure plug 88 to insure electrical isolation of these parts. The screws 18 and washer 14 may be of any desired insulating material such as fiber or the like. The fitting 12 has a reduced projection 18 which is adapted to be received in the aperture 8 in the upper fuse terminal cap 4, for cooperation with the clamping disk I1 to secure this refill unit in proper position within the fuse tube. The fitting 12 and insulating screw 18 are provided with aligned, substantially central bores for the reception of a highv resistance fusible wire 18 having its upper end secured to the upper end of the projection 18 o! the ntting 12. as by soldering or the like, and having its lower end extending through the gas generating material 44 and being fixed to the inner side wall of the tubular member I8. A calibrated low resistance fuse wire section 88 connects the fitting 12 with the end closure plug 88 to provide a circuit in parallel with the high resistance fuse wire 18. The reduced lower end portion I8 of the tubular member I8 is provided with an insulating throat 24, and a flexible conductor 38 has the end sleeve 34 thereon received in an aperture in the base of a generally cupshaped contact member 82, made of any desired resilient conducting material, and having the sides thereof split as shown in Fig. 3 to provide resilient contacting fingers 84. As is apparent from Fig. 3, the contact 82 substantially closes the gas passage through the lower end of the tubular member lil and the insulating throat 24, and the contact 82 is frictionally retained in position by the outwardly biased spring fingers 84.

In operation, the fuse of this embodiment of my invention, similar to those previously described, first opens the circuit through the short fusible section 88, and transfers the current through the device to the high resistance fusible wire 18. This wire is melted and acts to ignite the gas generating material 44 which builds up a gas pressure within the tubular member i8 of a value sumciently great to force the cupshaped terminal 82 downwardly through the passage 28 and out through the lower end'of the insulating throat member 24, to thereby interrupt the circuit through the fuse and extinguish the arc formed.

It should be noted that in all the embodiments of my invention thus far described the interruption of the circuit by one or more fusible elements is utilized to initiate the action of gas generating material, to provide a supply of gas for extinguishing the arc formed, and that the amount of gas generated is entirely independent of the current value of the arc established and will be substantially the same for each interruption of the fuse. In the embodiment of my invention shown in Fig. 3 the gas generated is additionally utilized to build up a pressure to separate two terminals of the circuit through the fuse, and this pressure will be the same irrespective of the current value of the arc formed. In other words, the fuses thus far disclosed are capable of acting with equal efliciency to extinguish arcs, and

therefore to interrupt the circuit, whether the arcs formed are of a high or low current value.

In Fig. 4 I have illustrated a fuse similar in many respects to the embodiments previously described but which utilizes a source of compressed gas which is released upon blowing of the fuse, and the released gases are directed through the arc formed to extinguish the same. Inasmuch as the structure shown in Fig. 4 has many parts in common with the structures previously described, like reference numerals will be used to designate like parts. In place of the tubular member I0 utilized in the fuses of the previously described embodiments o'f my invention, I have provided a tubular member 88 having an end plug 88 secured in the upper end thereof, as by welding, brazing, or the like. The end closure plug 88 is provided with a reduced projection 88 for extension through the opening 8 in the upper fuse terminal cap 4, to cooperate with the clamping disk I1 -to secure this refill unit in operative position within the fuse. lI'he end closure plug 88 is provided with a substantially central bore extending to the outer end of the projection 88, and which may be sealed by the threaded sealing plug 92. The lower end of the tubular member 88 is provided with an aperture which is closed by a fusible plug 94, and which in turn is connected by a short calibrated fusible section 8l to the sleeve 34 on the upper end of the flexible conductor 38. The tubular member 88 is provided with an insulating throat member 24 to provide a restricted or Venturi gas passage similar to that shown in Figs. 1 and 3. The tubular member 88 is adapted to be filled before sealing, with a gas under pressure such, for example, as air or the like.

In operation, when the current through the fuse exceeds a predetermined value the fusible section melts and an arc is struck to the fusible plug 94 which will, in turn, melt and thereby provide an opening in the lower end of the tubular member 88 through whichthe stored compressed gas may escape. When the fusible section 95 and plug 94 melt, an arc is struck from the adjacent portion of the tubular member 88 to the sleeve 34 on the flexible conductor 38. Obviously, gases escaping from the lower aperture in the tubular member 88 will necessarily be directed through the arc formed and will also tend to expel the flexible conductor 38 in the same manner described in connection with the embodiment of my invention shown in Fig. l. It should be noted also, that this fuse may berenewed by removing a blown refill unit and inserting a new one in the same manner as in the previously described embodiments.

In Fig. 5 I have shown a mounting for a fuse which may be utilized for supporting any of the fuses described heretofore, and which mounting is designed so that upon blowing of the fuse, the fuse tube terminals are released from engagement with respect to at least one line contact, and the fuse tube proper is supported so that it is movable in response to blowing of the fuse to move at least one of its terminals out of engagement with respect to at least one of the line contacts.

As shown in Fig. 5, a pair of insulators 98 and |88 are secured in spaced relation on a supporting member 98. The upper insulator 98, as appears in Fig. 5, is provided with a substantially L-shaped resilient contact and terminal member |82, one les of which is secured to the cap of the insulator 98 as by the machine screws IUI, and

'2,848,422 the other leg of .which extends substantially horizontallyl and is provided with an aperture for receiving the projection y|04 on the clamping disk I1 of the fuse, and is up-turned at its outer end as at |06. The`upper fuse ierrule may be pro.

supporting arms |08 for'fpivotally supporting therebetween a releasing lever H'. The lever ||0 is apertured as shown for the insertion :of a

hook stick or other operating member, and as appears from,v Fig. A isladapted to releasethe upper end of the fuse from the contactmember |02 when the lever I0 is rotated in a clockwise vided with a pair of outwardly extending spaced within the fuse tube to limit downward movement thereof. kIt will be obvious that with the construction shown in Fig. 6the -gas .pressure vdeveloped within the fuse tube will positively move 'the piston member |36 and consequently direction about its pivot. Such movement of the releaselever ||0 acts to raise the outer end |03v oi' the contact i 02 out-of engagement with the projection |04 on the upper fuse ferrule cap 4. With the fuse pivotally mounted at its'lowervend' it is obvious that the fuse may be ymoved in a generally counterclockwise direction to' become reengaged with the contact member |02 since the projection |04 on the fuse will engage. with the outer up-turned end |03 oi'.` the contact |02fand a cam the vsame upwardly to permit the projection t |04 to ride along the under surface of thepontact |02 until it becomesvaligned with the aperture therein, when it will be latched in the position shown inlig. 5. The vertical arm of the contact |02 as seen` in Fig. 5,-vmay servegas a terminal portion for the connection of a line conductor thereto. zV

The lower fuse ferrule 6 is provided with a pair of spaced inwardly extending arms ||2 for pivotally supporting therebetween, as by a pivot pin ||3, an intermediate portion of a supporting lever |4. The inner endfof the lever is provided with lower opposed trunnions ||8 adapted to be vf receivedv in notches provided in the sides of a split' contact member |22 secured to the outer end of the lower insulator |00. The contact |22 is provided with an integral downwardly extending terminal portion |24 for connection of a line conductor thereto. The inner end. portionof lever |4 is also provided with upper opposed positioning lugs |20 adapted to properly position the lever with respect to the contact |22, and also is provided with intermediate opposed stop lugs; |23

adapted to engage concave :stop portions |23 prof` vided .on the contact, as will be hereinafter described. The fuse link 33 is adapted to extend out of the lower end of the fuse tube and over a lateral projection on the outer end of the supporting lever ||4 and be secured tothe lever as by a thumb nut |32. f

In operation, when the fuse blows the flexible conductor 35 will be released within the fuse tube 2 andfaccordingly will no longer support the outer end projection |30 of the supporting lever` ||4. The fuse tube and lever are then freed-for relative movement and the fuse tubemay drop downwardly under the inuencev of gravity and the force exerted by theresilient contact |02, to disengage its upper projection |04 from the contact member 02 before the downward movement of lever ||4 is stopped by engagement of the stop lugs |25 thereon with the stop recesses |23 pro-` f The fuse tube 2 is vided on the contact |22.

the lower end of :the ilexible conductor 33 'down-- wardly to permit the fuse tube to be disengaged from its upper contact |02. This may be advantageous to prevent possible fouling of the lower opening through which the iiexible conductor 33 extends, and to positively insure movement at* least at the lower end `of this conductorinsteadY fof merey relying upon the force of gravity.

, this construction provides` ay totally'gl Moreove enclosed dropouty fuse construction.

In Fig. 7 I have shown a slightly modified form I of connection between `a'supporting lever |343.'y vgenerally similar tothe supporting levery 4 de,A

` scribed inl connection withFigs. vand 0 and t' adapted to be supported onva contact similar to.; the contact |22 of Fig.` 5, and the lower endot'a l fuse tube. The fuse tube inthis embodiment'of 1 niy invention is provided with a' lower endv `cap-2r.L |40 having an eccentric orfoset opening provided with a bushing |42 through 'which passes n. 'the lower end. of the flexible conductor` 35 to be y secured to the end cap l|40'asby a thumbfnut'ff |44. The end cap |43 is provided with a central aperture for receiving a piston member |43 pro-- portioned to relatively closely and slidablvj fit "j within the aperture through the end cap. {Ihe j piston |43 is also provided with a flangey |43 withinl the fuse tube to limit outward movement of the piston. In thenormal position of the fuse the lower end of the piston. |43 is adapted to em gage one arm of a bell crank lever |30, pivoted Aas at |5| between spacedl depending suDDOrtnZ Carl., integral with the lower fuse cap |40. The otherl A arm of the bell crank lever| is formed into a hook shape at its outer end forengagement with 1;, a pin |54. extending :between the'sides |33'of the l split outer end o! supporting lever/I 53. l 'I'he supe p y 'porting lever |53, similar to the lever ||4 previously described, is provided with positioning lugs |32. trunnions |34, and stop lugs |33,l simn cally connected to the lower fuse terminal cap then free to rotate about pivot ||5 in a clock/wise 1 direction outwardly of and away from the upper contact |02 to thereby introduce a large air gap in the circuit.

The release of the flexible conductor 33 may n be aided by the gas pressurey developed within the fuse and as shown in Fig. 6, the iiexible con- |40 by a flexible shunt |33'suitably secured to the levery and terminal cap. as'by the screws ||0. Ie-fv ver |53is pivotally mounted between spaced pivot supporting arms integral with the lower fuse terminal cap |40, as bythepivot pin |50. 4

In the operation of this-embodiment of my invention, it is apparent that normallyfthe lever l' |53 isjlatched.againstmovement relative'toy thev fuse tube 2 Vby a positive latching means |50, |52,

which is independent of the flexible conductor 33, and therefore independent of thel fusible means within the `fuse tube. The'lever |53 and fuse tube 2 are released for relative movement upon blowing of the fuse, `solely bythe gas'pressure developed within the fuse tube acting upon the piston member |43, whichris moved outwardly thereby, to rotate the bell crank lever |50 in a clockwise direction about its pivot |5| and thereby out of latching engagement with respect to the pin |54 on the lever |53.

then drop down and out of the circuit as deductor 33 may have secured thereto a relatively u Fig. 5.

torcgoing it should be apparentI that devised new and improved means for utieombustible or` explosive material las for. etingiiishin` g an electric n i will!! fuse. by cooling thel gas eireietroducinzu into them stream. I u, to obtain a predetermined u e t .of gas in a blast through the arc irre- 4 o! the current value of the arc estab- .illtdlbovathci'useinanyofits be either closed or have one fue# ewstruction l `to drop outof its associated cirat least 'one` terminal thereof to insert a relatively large x Furthermore, the drop- M auch an enclosed drop-out'fuse by the las pressure developed susennomimtnswemtnedmit.

l y, for assisting tbe dropest in mr www fuse cwtmww -H ,i of the current interrupted,

,i finaybeofapredeterminedvalue which Ind reliable in operation under Therefore. by providing a gas material which can be depended upon a constant quantity of las irrespect values interrupted by the fuse.

,i anarc.butalsoto'use aourceofgastobuildupapressureto operate meansfor releasing the fuse anomale `dit particularly t0 Perm med in art. that many changes and modificabe made in the particular structures l ,e 'without departing from the .broad spirit of my invention. Therefore, I dethe following claims be interpreted as aspoasible and that they be limited only w isexpreosly stated therein and Ibythe as my invention: l 1, In :i` dreist inten-opter, means for interthe circuit therethrough to establish an of a material independently capable ci, predetermined relatively large quantitles hot gases independent of the current or und are. means for initiating said upon operation oi said interrupting to open the circuit. means for cooling said and means for guiding said eases cooling means and thereafter through arc.

"2. a circuit interruptor, means for interrupting. `circuit therethrough to establish an arc, a combustible material capable of evolv..

be apparent that Ihave to enclosed mpciatedcircuit. Alsothegasgener`y ing relatively large 'quantities of hot gases as products of said combustion.' means for ignitlng said combustible material upon operation of said interruptor,` means for cooling said gaseous products of combustion, and means for guiding said gases past said cooling means and thereafter through the arc.

3. In a circuit interrupter, means for interruptingthe circuit therethrough to establish an arc, means of a material independeny capable of evolving predetermined relatively large quantities of hot gases independent of the current magnitude of said arc, means foi-,initiating said gas evolution upon operation of 'said interrupting f means to open the'circuit. means for cooling said evolved gases including material capable of evolv-l ing relatively cool lin-ionized gas when in proximity to said hot gases. and means for guiding said hot gases past said cooling means and thereafter through the arc.

4. In a circuit interrupter, means tor interrupting the circuit therethrough to establish an arc, means of a highly combustible material capable of evolving relatively large quantities of hot gases as products of combustion. electrical means for igniting said combustible material in response to operation of said interrputing means to interrupt the circuit, means for cooling said hot gases, and means for conducting said gases past said cooling means and thereafter through the arc formed by said interrupting operation of said interrupting means. 5. In a circuit interrupter, arc passage means. means for striking an arc in said' passage means, a source of arc extinguishing gas remote from said passage means. means energized by the arc struck in said passage means to liberate gases from said source. means for directing gases from said source throughsaid passage means to extinguish the arcformed therein. and the arc struck by said interrupter being confined solely to said passage means.

8. In a fuse. main fusible means connecting a pair of arcing terminals. a relatively high resistance ignition fusible means in parallel with said main fusible means, means of combustible material capable of producing relatively large quantities of gas as a product of combustion and positioned so as to be ignited by said ignition fusible means, and means for directing said gases between said terminals. whereby upon blowing of said main fusible means, said ignition fusible means blows and said terminals are subjected to a gas blast, in said sequence.

7. In a circuit interrupter, a pair of spaced arcing terminals dening an arcing space therebetween, means of combustible'material capable of producing relatively large'quantltles of gases as a product of combustion and located remote from said arcing space, means for striking an arc in said space between said terminals and lncludlng ignitionmeans positioned adjacent said combustible f material to ignite said combustible means in response to the striking of an arc in said arcing space, and means for guiding said combustion gases through` said arcing space to extinguish the arc.

8. In a fuse, a pair of spaced arcing terminals defining an arcing space therebetween, means of combustible material capable of producing relatively large quantities of gases as a product of combustion and located remote from said arclng space, fusible meansfor striking an arc between said terminals in said arcing space and including a fusible portion positioned adjacent said 772,848,409.- wmbustibie mman@ ignite-sala emanuele means in response to the strikingof an in.. said arcing space, and means for 'said combustion gases through lsaid arcing yspaoeto extinguishthearc.v

tainerof electrical conducting materialqdetach'- 9. A lcircuit interrupter including, incombination, separable contactsfor interrupting the circuit and establishingan arc, yany arc rmssagegfork said contacts having arestricted portionkadjacent said contacts through which atleast one of said contacts moves yin* drawing an arc, means` for supplyingwan-v arc extinguishing vfluid tothe end,

of said passage away from l the .direction of movement of saldone contact, and aflaringoutlet fol'` the other end ofsaid passage.r t

l10.` A circuit interrupter including, in combination, means formingan arc passagehaving an.

intermediate restricted portion,v separable contacts for lnterruptingfthe circuit and establishingV an arc longitudinally ofsaid` passage, means ,for supplying an arc extinguishing huid to one en d of said passage in la'zone surrounding one of said contacts, and a Venturi outlet for said passage. x

nation, a pair of separable contacts for interrupting the circuit and establishing an arc, an arc passage for said contacts with one of said contacts mounted at one end of said passage in fixedspaced relation relative to the walls oisaid passage, the otherrof said contacts lbeing movable towards the other end-of lsaid passage to establish an arc, and means for supplying an arc extinguishing uid under 'pressure'in the `space between said one contact and' said passage for movement about said one contact and through Isaid passage in response to separation of said contacts.

13. A fuse reiiil unit, including a container of electrical conducting material having attaching.

means and terminalmeans at one end thereof, tubular means of insulating material forming an arc passage secured to the other end of said container, a second terminal extending out the open outerend of said v e, means including a fusible element connecting said container and second terminal, means in said container capable of evolving an arc extinguishing gas under pressure in response to fusion of said fusible element, and the other end of said container communicating with said arc passage.

14. A fuse refill unit, including a container having attaching means and terminal means at one end thereof,` means of combustible, gas forming material in said container adjacent said one end thereof, cooling means positioned in said container between said gas forming means and the other end of said container, tubular means forming an arc passage secured to the other end of said container, a second terminal extending out the open end of said passage, means including a fusible-element connecting said terminals, said fusible means including means for igniting said combustible material in response to fusion of said fusible element, and the other end of said a material capable of, evolving a predeterminedablysecured in` said tube adjacent one end there'.

effin cnducuve reissen tn the corresponding one of'saidl terminals, gasgeneratingmaterial. in said container,- tubular means of insulatingmaterialf `forming an arc esecured to saidcontainer in said tube and communicating with the interior* of said'. container, fusible meansxinlsaidgtubular means adapted toj .open the. circuit and initiate operationbf said.k gas generatingmeans.. said fu-f .sible means being Vconnected said.y conjf itnlner and the other,nrsnldternunalsmndaua of'said parts being detachable fromy said tube andtermlnau as afunlt.V f

16.- A fuse revllunit including acontainer'rof'v conductingmaterial havingattachment and ter-v minal .means at :oneLendthereof, and a. tubular -extension at vthe other endthereotublllarmeans of insulating material connectedV to said exten'- e sion and. forming a; continuation thereof topro-U vide an arc passage,va Lsecond terminal in= said passage. means including a fusible element connecting .said secondV terminal to Isaid container:- means in said container capable of l evolving an arcextinguishingfgas in response to fusion'of said fusible element, and said'arc passage communicating` with the interior:y of said f a container. i 17. In a circuit interrupter, an interrupter chamber having an opening, means for establishingan arc adjacent saidopeningin a position to be engaged byy gases flowing out through said chamber opening. meansin said chamber of amount of hot gasesfindependent of the currentmagnitude of said arc, cooling means` ink said chamber interposed between said gas evolving material and said opening, and means for initiating gas evolution by said gas evolving means in ,response to the striking oran arc, whereby said arc is subjected to a blast'of cool gas to extinguish the same.

18. In a circuit interrupter, an interi-aptes chamber having an opening, means for establish-l ing an arc with at least a .portion in said opening, means in said chamber of a material capable of evolving a predetermined amount of hot gases independent of the current magnitude of said arc, cooling means in said chamber Vinterposed between said gas evolving mater-island said openling. and means for initiating gas evolution by said gas evolving means in response to the striking of an arc, whereby said arc is subjected to a blast of cool gas to extinguish the same.

19; In a circuit interrupter, an lnterrupter chamber-having anv opening, means of insulatingv material forming an arc passage extending outwardlyjfrom said opening, means for establishingan'arc with at least a portion of the arc in said passage at least vwhen a blast of gas passes out through said passage. means in said chamberoiamaterial capable of evolving a predetermined amount of hot gases independent of the current magnitude of said arc, cooling means in said chamber interposed between said gas evolving material and said opening, and means for initiating gas evolution by said gas evolvingl means in response to the striking of an arc, whereby said aro is subjected to a blast of cool gas to extinguish the same.

20. In a circuit interrupter, an interrupter chamber having an outlet passage extending 15.11. In infuse, vanlf insulating :fuse` tube terminals adjacent opposite:endatliereotlafcon-,

means for establishing an arc predetermined amount of hot gases independent of the current for initiating gas evolution by said gas evolving means in response to the striking of an arc. whereby said arc is subjected to a blast of cool gas to extinguish the same.

21. In a circuit interrupter. a pressure container for an arc ex gas under pressure. means of insulating material forming an arc passage secured at one end to said container, in said passage and concurrently establishing an opening in said container at said one end of the a blast of gas through the saine.

32. In a circuit interrupter, a pressure container for an arc ex gas under pressure, means of insulating material' forming an arc passage secured at one end to said container. said container having a fusible terminal wall poridonatsaidoneendofsaidpassagaaterminnl wail portion and movable arc to extinguish the 23. In a fuse. main fusible means connecting a pair of arcing terminals. a relatively high resistance ignition fusible means ily and connected in parallel with said main arc passage to cause 4 means serially contacts.

fusible means so said main fusible material capable a sas blast, in said sequence.

24. Inua fuse, separable contacts and fusible means serially connected in the circuit, an arc e having a restricted portion adjacent said one of said contacts forming a displaceable obstruction in said passage, means responsive to fusion of said fusible means for supplying a predetermined quantity of arc extingas under pressure to one end of said passage independent of the current magnitude of the arc, whereby said one contact will be displaced through said passag upon fusion of said fusible me to draw an arc of predetermined length irres tive of the magnitude of the current interrupted.

25. In a' fuse, separable contacts and fusible connected in the circuit, means responsive to fusion of said fusible means for liberating a predetermined quantity of arc extinguishing gas under pressure independent of the current magnitude of the arc. means associated with at least one of said contacts responsive to said gas pressure for separating said contacts, and means for guiding said gas through the arc drawn between said contacts.

HERBERT L. RAW'LINS.

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