US2788418A

US2788418A - Circuit interrupter

Info

Publication number: US2788418A
Application number: US417622A
Authority: US
Inventors: James B Owens
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1954-03-22
Filing date: 1954-03-22
Publication date: 1957-04-09
Anticipated expiration: 1974-04-09
Also published as: GB765287A; FR1133367A

Description

p l 9, 1957 J. B. OWENS ETAL 2,788,418

CIRCUIT INTERRUPTER Filed March 22, 1954 3 Sheets-Sheet 1 Fig. l.

April 9, 1957 J. B. OWENS ET AL 2,788,418

CIRCUIT INTERRUPTER Filed March 22, 1954 3 Sheets-Sheet 2 United States CIRCUIT INTERRUPTER Pa., a corporation of Pennsylvania Application March 22, 1954, Serial No. 417,622 17 Claims. (61. 200-148) This invention relates to circuit interrupters in general, and, more particulariy, to improved interrupting devices for circuit interrupters of the fluid-blast type.

in United States patent application filed September 23, 1953, Serial No. 381,937 by James B. Owens, and assigned to the assignee of the instant application, there is disclosed and claimed a novel form of circuit interrupting device, particularly one of the load-break disconnecting-switch type, in which a main disconnecting-switch blade bridges a pair of spaced circuit terminals, and with which is associated a load-break interrupting device and an interrupter isolating blade to relieve the main switch blade from any arcing. it is one of the objects of our invention to improve upon the interrupting structure described in this application.

It is still a further object of our invention to provide an interrupter construction for forcing a blast of fluid against an established arc to rapidly effect the extinction thereof.

A more specific object of our an improved puffer interrupting device in which movement of the movable contact is effective to actuate the device, and in which a blast of fluid is directed against the established arc to quickly bring about circuit interruption.

in United States patent application filed July 19, 1951, Serial No. 237,592, now United States Patent 2,757,261, issued July 31, 1956, to Harry I. Lingal, Thomas E. Browne, in, and Albert P. Strom, and assigned to the assignee of the instant application, the use of a new gas for arc-extinguishing purposes is set forth and claimed, this gas being sulfur hexafluoride (SP6), which exhibits phenomenal arc-extinguishing properties. As set out in said application, it is advisable, in certain constructural aspects, to use a fluorinated polymer insulating material, and particularly, solid fiuorocarbons, such as polytetraiiuoroethylene, polychlorotrifluOroethylene, or polyvinylfluoride, since none of these materials reacts with the products of decomposition of the gas, when subjected to an arc, to form corrosive acids. However, polytetrafluoroethylene is quite expensive, being at the time of filing this application approximately $14 a pound. To provide a puffer assembly of this material is ere pensive, and if such a putter assembly is moved within a porcelain weather casing, or through a hollow cylinder of ceramic material, the weather casing or the cylinder of ceramic material needs to be machined to relatively close tolerances, all of which increases the expense of manufacturing such a device.

it is, therefore, a further object of our invention to provide an inexpensive puiier assembly, which, when used in conjunction with a gas, such as SP6, needs to employ only a relatively small quantity of polytetrafluoroethylene, polychlorotrifluoroethylene or polyvinyl fluoride.

In addition, it has been found from a result of research tests that prolonged scraping of the polytetrafluoroethylinvention is to provide atent O 2,788,418 Cc Patented Apr. 9, 1957 ene puffer on the porcelain tube formed a film that was susceptible to electrical breakdown. It is, therefore, still a further object of our invention to provide an effective, relatively cheap puffer assembly, easy to manufacture, and providing longer operational life while in service without danger of dielectric breakdown.

An ancillary object of our invention is to provide an improved constructional mounting arrangement for a puffer assembly, particularly one employing a relatively stationary piston.

Further objects and advantages of our invention will be readily apparent upon reading the following specification taken in conjunction with the drawings, in which:

Figure 1 is a side elevational view of a circuit interrupter, of the load-break disconnecting switch variety, incorporating our invention and illustrated in the closed circuit position;

Fig. 2 is an enlarged, fragmentary, vertical sectional view through the circuit interrupting device of Fig. l, the contact structure being likewise shown in the closedcircuit position;

Fig. 3 is an enlarged, fragmentary, vertical sectional view through the interrupter casing of Fig. 2, the contact structure being illustrated in the fully open-circuit position;

Fig. 4 is a fragmentary, sectional view taken along the line IV-IV of Fig. 3;

Fig. 5 is a plan view of one of the valve details of the interrupter shown in Fig. 3; and

Fig. 6 is a plan view of a washer element employed in the valve structure shown in Fig. 3 of the drawings.

Referring to the drawings, and more particularly to Fig. 1 thereof, the reference numerals 13 designate supporting porcelains, which extend, in this particular instance, vertically upwardly from a channel-shaped base member, not shown. As well known by those skilled in the art, the circuit interrupter 4 may be mounted in either the horizontal position, as shown, or in an inverted position, or in a vertical position, depending upon the application requirements. Naturally, the particular mounting arrangement has nothing to do with our invention, and for purposes of illustration, the load-break switch is illustrated in a horizontal position. The supporting porcelain 2 is rotatable, and, when rotated, serves to actuate a mechanism provided within a housing 5 to effect first an axial rotative movement of the main switch moving contact or blade 6 about its axis to reduce contact pressure between the end 7 of the blade 6 and the stationary main switch jaws 8, meanwhile breaking any ice which may have formed thereat.

Subsequently, the mechanism disposed interiorly within the housing 5, when actuated by rotative motion of the rotatable insulator column 2, serves to bodily rotate the main switch moving contact 6 upwardly away from the main stationary switch jaw contacts 8, separating therefrom so that the circuit will then be compelled to pass through a circuit interrupting device 10, which is mounted adjacent the switch jaws 8 upon supporting insulator 1.

The tip end 11 of the main switch-blade 6 strikes a laterally jutting projection 12 disposed at the end of a crank arm 13 to effect rotation of a drive shaft 14 to effect operation of an overcenter toggle spring mechanism 15, disposed interiorly within a housing 16 positioned at the upper end or" the interrupting device 10.

During the time that the main switch blade 6 has separated from the jaw contacts 8, the main circuit extends from the terminal pad 17 to the relatively stationary contact 18 (Fig. 2), thence by way of the movable contact 19 and through lift rod 20 to flexible connection 21, the other end of which is secured, as at 22, to a portion of the conducting housing 16. An upper stationary terminal iar'seais 23, more clearly shown in Fig. 1, has a forked outer end, not shown, which receives the end 24 of the interrupter isolating blade 25, which .is biased by a spring assembly 26 in the direction, as indicated by the arrow 27, toward the main switch-blade 6. The lower end of the interrupter isolating blade 25 is pivotally mounted to the side wall of the cam housing 5, as indicated in Fig. 1. Thus, the circuit will pass through the interrupter isolating blade 25 to conducting cam housing 5 and finally through support casting 9 to line terminal connection plate 28.

As will become more clear hereinafter, engagement of the projection 12 by the tip end 11 of the main switchblade 6 causes rotation of the drive shaft 14 and actuation of the overcenter mechanism 15 to cause upward separating motion of the movable contact 19 (Fig. 2) away from the relatively stationary contact 18 to estabiish an arc therebetween. with the

contacts

18, 19 to effect a blast t fluid, inthis particular instance a gas such as sulfur hexafiuoride, against the established arc to effect the extinction thereof. Subsequently, a laterally extending arm 39, secured to and movable with the main switch blade 6, picks up the interrupter isolating blade 25 and carries the latter therewith to the fully open-circuit position of the device, as indicated by the broken lines 31 of Fig. 1. In this position, the crank arm 13 is in the position indicated by the broken lines 32. The interrupter is then fully open.

A pufier assembly 29 is associated During the closing operation, the main switch blade 6, I

together with the interrupter isolating blade 25, swing in a counterclockwise direction about the shaft 33 of the hinge end 34 of the load-break switch, being biased together by the spring assembly 26. During this closing movement, the tip 24 of the interrupter isolating blade 25 first engages the forked end of the stationary terminal 23 at the top end of the circuit interrupting device 10. The circuit through the interrupter 4 is not closed, however, because of the separated condition of the

contacts

18, 19 at this time. Further, counterclockwise, closing rotative travel of the main switch moving contact 6 causes the tip end 11 thereof to strike the projection 35, which in the position 32 is in the path of the end 11 of the switch blade 6. As a result, the tip 11 of the switch blade 6 forces the projection 35, and hence, the crank arm 13, in a clockwise direction about the drive shaft 14 to effect overcenter spring action of the toggle mechanism 15 within the housing 16, to effect thereby snap closing motion of the movable contact 19 against the upper end of the stationary contact 18. This will complete the circuit through the interrupter 4, and continued travel of the main switch blade 6 will cause the contact end 7 thereof to slide between the spaced jaw contacts 8, making contact therewith. Final rotative closing motion of the rotatable insulator column 2 will effect axial rotative motion of themain switch-blade 6 to bring the wider dimension of the contact 7 against the spaced jaws 8 to efiect their expansion, and thereby bring high contact pressure to bear between the contacts 7, 8. Thisnot only provides a low resistance path through the interrupter 4, but also effectively shorts out the circuit through the circuit interrupting device 10. I

The circuit interrupting device 10 is more clearly set out in Fig. 2 of the drawings. It will be noted that the putter device 29 includes a relatively stationary piston 36,

which cooperates with a movable operating cylinder 37, the latter preferably being formed of aluminum tubing. The lower end of the operating cylinder 37 is rolled, as at 38, into an indentation 38a provided annularly about a spider member 39. The conducting spider member 39 not only provides a support for the movable contact 19,

but also provides a plurality of apertures 41, through which gas may pass during the opening operation. It will be noted that disposed in the side walls of the operating cylinder 37 are a plurality of venting ports 42,

opening travel of the operating cylinder 37.

Associated with the lower end of the movable operating cylinder 37 is orifice means 43, in this particular instance including an elongated orifice member 44, of substantiaily tubular configuration, which is screwed, as at 45 (Fig. 3), to a downwardly extending flange portion 46 of the spider member 39. Preferably, the orifice member 44 is formed from polytetrafiuoroethylene, polychlorotrifluorcethylene or polyvinyl fluoride, and has the length of its orifice 77 several times the diameter of the orifice to give most effective deionizing action. A shield disc member 47 preferably of polytetrafluoroethylene, polychlorotrifluoroethylene, or polyvinyl fluoride is screwed, as at 43, to the end of the orifice member 44-. he shield 47 does not have to have a close fit within the interior the insulator column which does not have to be machined as has been the case where the separate metal cylinder 37 and piston 36 were not provided. The function of the shield is to protect the metal parts above it from hot are products, rather than to act as a piston, and to prevent fiashover between the stationary contact 13 and metal spider 39.

Preferably, valve means are associated with the stationary piston as, in this instance comprising a washer 49, more clearly shown in Fi 6 of the drawings, which seals the opening 50 through the piston 36 during upward travel or the operating cylinder 37 during the opening operation. The washer 49 is supported on an apertured ring shown in detail in Fig. 5 of the drawings, the latter being secured fixedly in place within a downwardly extending flange portion 52 of the stationary piston 36 by peening over spaced portions of the flange member 52.

As a result, a valve, generally designated by the reference numeral 53, is associated with the stationary piston 36 functioning by fluid pressure to close the opening 50 during the upward driving motion or" the operating cylinder 37, and permitting, during t.e downward stroke of the operating cylinder 37, free flow of into the interior 5d of the cylinder 37 through the holes 55 of the apertured ring 51, as indicated by the arrows 56 of Fig. 3.

The specific operating mechanism i5, disposed Within the housing 1-6, forms no part of our invention, except as it cooperates with the rest of the structure, and the general principles of operation thereof are set forth and claimed in United States Patent No. 2,769,063 issued October 30, 1956 on an application filed October 26, 1951, Serial No. 253,321 by Iarry .i. Lingal, entitled Circuit interrupting Device, and in the division of that application Serial No. 576,875 filed April 9, 1956, both assigned to the assignee of the instant application. Generally, the operation is such that counterclockwise opening travel of the drive shaft 14 causes corresponding counterclockwise travel of a crank arm 57 secured thereto and disposed interiorly within the mechanism housing 16. A floating link 58 connects the outer end 59 of the crank arm 57 with the outer end of toggle arm to which one end of a tension spring 61 is secured. The toggle arm 69 rotates about a shaft 62, about which also rotates a second toggle arm s3, to which, as at 64, the other end of the tension spring at is secured.

From the foregoing, it will be noted that the tension spring 61 is an overcenter tension spring which will effect snap opening and snap closing of the contact structure. A support bracket 65 is secured to the upper end of the housing 16 on a pair of integral pedestal supports 66, 67. To the outer end of the support bracket 65 is pivotally mounted, at 68, a lever 69, to the lower end of which is pivotally connected, as at 79, a floating lever '71, which is pivotally connected, as at 54, to the second toggle arm 63 of the mechanism 15. The lower end of the floating lever 71 is pivotally connected, as at 72, to the upper end of the con act rod 2d. As well known by those skilled in the art, the foregoing linkage insures substantially straight-line motion of the upper end of contact rod 20.

The general manner of operation of the overcenter toggle spring mechanism 15 is as follows: counterclockwise rotation of the drive shaft 14, as effected by the externally disposed crank-arm 13, effects through the linkage 58 corresponding counterclockwise rotation of the toggle arm 60, and hence movement of the right-hand end 61 of the tension spring 61 upwardly toward the center line 73 of the toggle mechanism 15. Nothing happens until the line of action of the overcentcr spring 61 passes over the center line 73 and begins to exert a torque upon the second toggle arm 63 about the shaft 62. This will effect a snap action of the second toggle arm 63 in a clockwise direction about the shaft 52, to thereby effect a counterclockwise rotative travel of the floating lever 71 about its pivotal connection with the guide lever 69. This all occurs with a .ap action, as effected by contraction of the tension spring so that the floating lever 71 will be arrested A 74, as indicated by the dot-dash lines 75 of Fig. drawings.

The contact rod 20 will, by this means, be snapped to its upward position, carrying with it the entire operating cylinder 3'1 movable contact 19 and orifice means $3. The upward movement of the operating cylinder 37 will, because of the presence of the venting ports 42, effect no compression of gas within the interior of the operating cylinder 37, but during this time the movable contact 19 will be picking up speed and gathering kinetic energy. When the operating cylinder 37 has traveled upwardly far enough during the opening operation, so that the venting ports 42 will have passed over the stationary piston 36, further upward movement of the operating cylinder 37 will effect a compression of the gas within the interior 54 of the operating cylinder 37, which will forcethis compressed gas through the apertures s of spider member 39 and adjacent the are 7a, which is drawn for purposes of illustration in Fig. 3 of the draw logs. The compressed gas in passing along the interior 77 of the orifice 44 will effect deionization of the are 76 and will effect the extinction thereof.

As mentioned, during this upward travel of the operat ing cylinder 37, the valve 53 will close. in other words, the washer 4? will be forced by the gas pressure upwardly to effect closing of the opening 5% in stationary piston 36.

During the closing stroke, the operating cylinder 37 is moved downwardly with a snap action by the overcenter spring mechanism to effect rapid engagement between the

contacts

19, 18 to complete the circuit through the interrupting device 19. During this downward movement of operating cylinder 37, the gas will be sucked through the opening 5% and through the apertures 55 of apertured ring 51, the washer 49 remaining in its lower position, as indicated in Fig. 3, immediately adjacent the support ring 51.

From the foregoing description of our invention, it will be apparent that the are 76 is effectively blasted by gas passing out of the operating cylinder 37 and through the elongated orifice 44. It will be noted that the operating cylinder 37 is guided at two points. One point will be'between the piston 36 and the inner side wall of the operating cylinder 37, and the other point will be at the pivotal connection 72 of contact rod Ltd.

From the foregoing description, it will be apparent that careful machining of the inside of the porcelain ing 30 is unnecessary, and the amount of polytetrafluoroethylene, polychlorotrifiuomethylene or polyvinyl fluoride used is reduced. Also, no conducting films are formed along the inner wall of the casino so, since the stationary piston 36 and the straight-line motion of the contact rod provides essentially all the guiding action nec'essaryfthe friction or rubbing action between the 2 of the CES- by a sto pedestal 6 inner wall 79 of casing 80 and shield disc 47 being negligible.

The stationary piston 36 has an integrally formed upstanding flange portion 81, within which is positioned and welded the end of a metallic tube 82. The upper end of the tube 82 is received within a recess 83 of a nut 34, which threads, as at 85, into a tapped opening 86 provided in a mounting plate 87. Mounting bolts 88 secure the mounting plate 87 to an annular flange ring 89 cemented, as at 90, to the upper end 91 of the porcelain weather casing 80.

A gasket 92 is interposed between the end of casing 8i and the mounting plate 87 to provide a gas-tight construction, Additional mounting bolts 93 secure the mounting plate 87 to a lower inwardly extending flange portion of the mechanism housing 16. A gasket 95 provides a gas-tight connection. The contact lift rod 26 extends interiorly through the metallic tube 82.

The relatively stationary contact 18 is disposed at the upper extremity of a contact rod 96 resiliently mounted to a metallic closure plate 97, the latter being secured by mounting bolts 98 to a flange ring 99. The flange ring 99 is secured to the lower end 100 of the porcelain casing 89 by cement 101. A gasket 102 provides a gastight connection.

The pressure of the gas within the casing 80 is measured by a gauge 1% and a gas inlet opening 104 is provided for supplying gas, such as SP6, into the casing 80 as more fully covered in the aforesaid application Serial No. 576,875. Mounting bolts 1G5 secure the closure plate to the support casting 1G6 supported by insulator column 1.

From the foregoing description, it will be noted that the fixed piston 36 and the operating cylinder 37 are secured, or mounted from the top housing 16. Thus upon removal of the mounting bolts 83, the entire top housing 16 may be lifted away from the casing 80 carrying there with the entire puffer assembly 29. Obviously, this facilitates assembly and disassembly of the interrupter 10. Similarly, the casing 80 may be detached or attached to the closure plate 97, to which the stationary contact rod. 96 is secured.

Although we have illustrated our invention as employing sulfur hexafiuoride gas with insulating structural members of polytetrafiuoroethylene, polychlorotrifiuoroethylene, or polyvinyl fluoride, it is to be understood that some aspects of the invention may be applied to other fluids, such as air, helium, carbon dioxide, nitrogen, etc., in combination with other insulating materials. In each case, the advantage of having the metallic walls of the operating cylinder 37 provide the guiding function is evident.

Although we have shown and described a specific construction, it is to be clearly understood that the same was merely for the purpose of illustration, and that changes and modifications may be readily made therein by those skilled in the art, without departing from the spirit and scope of the invention.

We claim as our invention:

1. The combination in a circuit interrupter of a sealed casing containing an arc-extinguishing gas comprising sulfur hexafluoride, a relatively stationary piston, a movable operating cylinder having movable orifice means of a fiuorinated polymer insulating material disposed adjacent one end thereof, a movable contact associated with the orifice means and secured to the movable operating cylinder to effect the movement thereof, and the gas being forced during the opening operation of the circuit interrupter out of the movable cylinder and through the orifice means to effect extinction of the are.

2. A circuit interrupter including a hollow sealed casing of insulating material containing an arc-extinguishing gas comprising sulfur hexafiuoride, a relatively stationary contact extending within the hollow casing adjacent one end thereof, a relatively stationary piston extending into the other end of the hollow casing, a movable operating cylinder surrounding the relatively stationary piston and creams having a movable contact secured thereto, the contacts being separable to establish an arc, and opening movement of the movable contact and operating cylinder forcing gas comprising sulfur hexafluoride against the established arc to effect the extinction thereof.

3. A circuit interrupter including a hollow sealed casing of insulating material containing an arc-extinguishing gas comprising sulfur hexafiuoride, a relatively stationary contact extending within the hollow casing adjacent one end thereof, a relatively stationary piston extending into the other end of the hollow casing, a movable operating cylinder surrounding the relatively stationary piston and having a movable contact secured thereto, an orifice of a fluorinated polymer insulating material secured to and movable with the operating cylinder, the movable contact being disposed within the orifice, separation of tee contacts establishing an are within the orifice, and opening movement of the movable contact and operating cylinder forcing gas from within the operating cylinder through the orifice and against the established arc to efiect the extinction thereof.

4. A circuit interrupter including a tubular casing of insulating material containing sulfur hexafiuoride gas, a relatively fixed piston mounted in the tubular casing, a

movable operating cylinder containing an orifice and shield disc of a fiuorinated polymer insulating material, a relatively stationary contact disposed within said tubular casing, a cooperable movable contact disposed within the orifice and movable with the movable operating cylinder, said contacts being cooperable to establish an arc,

and sulfur hexafiuoride gas being compressed out of the operating cylinder through the orifice and against the arc to effect the extinction thereof.

5. A circuit interrupter including a tubular casing of insulating material containing sulfur hexafiuoride gas, a relatively fixed piston mounted in the tubular casing, a movable operating cylinder containing an orifice of a polymer of fluorinated ethylene selected from the group consisting of polytetrafiuoroethylene and polychlorotrifluoroethylene, a relatively stationary contact disposed Within said tubular casing, a cooperable movable contact disposed Within the orifice and movable with the movable operating cylinder, said contacts being cooperable to establish an arc, and sulfur hexafiuoride gas being compressed out of the operating cylinder through the orifice and against the arc to effect the extinction thereof.

6. A circuit interrupter including a sealed casing containing a fixed quantity of arc-extinguishing gas, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and movable over the fixedpiston, a relatively stationary contact, a movable contact carried by the movable cylinder and cooperable with the relatively stationary contact to establish an arc, and gas compressed within the movable cylinder by the fixed piston being forced into the arc to facilitate the extinction thereof.

7. A circuit interrupter including a sealed casing containing a fixed quantity .of arc-extinguishing gas, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and movable over the fixed piston, said cylinder having relatively small clearance with respect to the inner wall of the tubular member, a relatively stationary contact extending into the tubular member from the other end thereof, orifice means carried by the movable cylinder, a movable contact carried by the movable cylinder and cooperable with the relatively stationary contact to establish an arc, and gas compressed within the movable cylinder by the fixed piston being forced through said orifice means and into the arc to facilitate the extinction thereof,

8. A circuit interrupter including a sealed casing containing a fixed quantity of arc-extinguishing gas, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and movable over the fixed piston, a relatively stationary rod-shaped contact disposed adjacent the other end of the tubular member, an orifice carried by the movable cylinder, a movable contact carried by the movable cylinder and disposed within said orifice, the relatively stationary and movable contacts being cooperable to establish an arc, the rod-shaped relatively stationary contact extending into the orifice in the closed circuit position of the interrupter, and gas compressed within the movable cylinder by the fixed piston being forced through the orifice into the arc to extinguish the same with the orifice being movable over the end of the rod-shaped stationary contact.

9. A circuit interrupter including a sealed casing containing a fixed quantity of arc-extinguishing gas comprising sulfur hexafiuoride, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member f om one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and. movable over the fixed piston, a relatively stationary contact, a movable contact carried by the movable cylinder and cooperable with the relatively stationary contact to establish an arc, and gas comprising sulfur hexafiuoride compressed Within the movable cylinder by the fixed piston being forced into the arc to facilitate the extinction thereof.

10. A circuit interrupter including a sealed casing containing a fixed quantity of arc-extinguishing ga comprising sulfur hexafiuoride, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and movable over the fixed piston, said cylinder having relatively small clearance with respect to the inner wall of the tubular member, a relatively stationary contact extending into the tubular member from the other end thereof, orifice means of a fiuorinated polymer insulating material carried by the movable cylinder, a movable contact carried by the movable cylinder and cooperable with the relatively stationary contact to establish an arc, and gas comprising sulfur hexafiuoride compressed Within the movable cylinder by the fixed piston being forced through said orifice means and into the arc to facilitate the extinction thereof.

ll. A circuit interrupter including a sealed casing containing a fixed quantity of arc-extinguishing gas comprising sulfur hexafiuoride, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and movable over the fixed piston, a relatively stationary rod-shaped contact disposed adjacent the other end of the tubular member, an orifice of a fluorinated polymer insulating material carried by the movable cylinder, a movable contact carried by the movable cylinder and disposed within said orifice, the relatively stationary and movable contacts being cooperable to establish an arc, the rod-shaped relatively stationary contact extending into the orifice in the closed circuit position of the interrupter, and gas comprising sulfur hexafiuoride compressed within the movable cylinder by the fixed piston being forced through the orifice into the arc to extinguish the same with the orifice being movable over the end of the rodshaped stationary contact.

12. The combination in acircuit interrupter of a sealed casing containing a fixed quantity of arc-extinguishing gas, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and movable over the fixed piston, said movable cylinder supporting an elongated tubular orifice, a movable contact disposed adjacent one end of the tubular orifice and carried by the movable cylinder, a relatively stationary contact extending into the tubular member from the other end thereof and extending in the closed circuit position of the interrupter through the tubular orifice to engage the movable contact, during the opening operation the tubular orifice being movable with the movable cylinder 50 that the relatively stationary contact traverses the length of the tubular orifice, and the tubular orifice then moves away from the end of the relatively stationary contact.

13. The combination in a circuit interrupter of a sealed casing containing a fixed quantity of arc-extinguishing gas comprising sulfur hexafiuoride, said casing including a tubular member of insulating material, a fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the fixed piston, a cylinder supported from the same end of the tubular member and movable over the fixed piston, said movable cylinder supporting an elongated tubular orifice of a fluorinated polymer insulating material, a movable contact disposed adjacent one end of the tubular orifice and carried by the movable cylinder, a relatively sationary contact extending into the tubular member from the other end thereof and extending in the closed circuit position of the interrupter through the tubular orifice to engage the movable contact, during the opening operation the tubular orifice being movable with the movable cylinder so that the relatively stationary contact traverses the length of the tubular orifice, and the tubular orifice then moves away from the end of the relatively stationary contact.

14. The combination in a circuit interrupter of a tubular casing sealed from the ambient air and containing an arc-extinguishing gas comprising sulfur hexafiuoride, a relatively stationary piston disposed within said tubular casing adjacent one end thereof, a movable operating cylinder having movable orifice means of a fluorinated polymer insulating material disposed adjacent one end thereof, a movable contact associated with the orifice means and secured to the movable operating cylinder to effect the movement thereof, a relatively stationary contact positioned adjacent the other end of said tubular casing, the movable contact being cooperable with said relatively stationary contact to establish an are within said orifice means, and the gas being forced during the opening operation of the circuit interrupter out of the movable cylinder and through the orifice means to effect the extinction of the are.

15. A circuit interrupter including a hollow tubular casing of insulating material sealed from the ambient air and containing an arc-extinguishing gas comprising sulfur hexafiuoride, a relatively stationary contact extending within the hollow tubular casing adjacent one end thereof, a relatively stationary piston extending into the other end of the hollow tubular casing, a movable operating cylinder surrounding the relatively stationary piston and having a movable contact secured thereto, movable orifice means associated with said movable contact, the contacts being separable to establish an are through said orifice means, and opening movement of the movable contact and operating cylinder forcing gas comprising sulfur hexafiuoride against the established are within said orifice means to effect the extinction thereof.

16. A circuit interrupter including a casing sealed from the ambient air and containing a quantity of arc-extinguishing gas, said casing including a tubular member of insulating material, a relatively fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the relatively fixed piston, a movable cylinder supported from the same end of the tubular member and movable over the relatively fixed piston, a relatively stationary contact projecting into the other end of said tubular member of insulating material, a movable contact carried by the movable cylinder and cooperable with the relatively stationary contact to establish an arc, and gas compressed within the movable cylinder by the relatively fixed piston being forced into the arc to facilitate the extinction thereof.

17. A circuit interrupter including a casing sealed from the ambient air and containing a quantity of arc-extinguishing gas, said casing including a tubular member of insulating material, a relatively fixed piston, a supporting member extending into the tubular member from one end thereof and supporting the relatively fixed piston, a movable cylinder supported from the same end of the tubular member and movable over the relatively fixed piston, said movable cylinder having relatively small clearance with respect to the inner Wall of the tubular member, a relatively stationary contact, a movable con-tact carried by the movable cylinder and cooperable with the relatively stationary contact to establish an arc, and gas compressed within the movable cylinder by the relatively fixed piston being forced into the arc to facilitate the extinction thereof.

References Cited in the file of this patent UNITED STATES PATENTS