US2052232A - Electric switch - Google Patents

Description

1936- J. KOPELlOWiTCH ET AL 2,052,232

ELECTRIC SWITCH Filed Nov. 11, 1933 Patented Aug. 25, 1936 UNETED STATES 2&5223

PATENT GFHQE Switzerland, assignors to Brown Boveri & Cie.,

Airtiengesellschaft Baden, Switzerland, a

joint-stock company of Switzerland Application November 11, 1933, Serial No. 697,580 In Germany November 11, 1932 7 Claims.

This invention relates in general to electric switches having pressure vessels and more particularly to switches in which a limited amount of arc extinguishing fluid contained in a pressure vessel is used for extinguishing the are exteriorly thereto.

In switches employing a reduced amount of arc extinguishing fluid, thearc produced upon disengagement of the contacts is generally extinguished by deionization due to the contact and proximity of the arc with vapor produced from the fluid. If such vapor is produced by drawing the arc out within a body of fluid, a large amount of fluid becomes necessary. In addition, when the switch is being closed the moving contact must then travel through an appreciable depth of fluid previous to engaging with the flxed contact, thereby establishing a protracted connection of the circuit through the fluid during the closing operation. If the arc extinguishing fluid utilized is appreciably conductive, as is the case when undistilled water is utilized, sufllcient current may flow between the contacts during closing operation to cause large amounts of vapor to be produced, thereby hindering or even preventing completion of the closing operation. The fluid to be vaporized may also be forced into the arc path; if the clearance between the moving contact and the fluid constituting a passage therefor is small, difliculty is then experienced in displacing a. suflicient amount of fluid and, if such clearance is large, the fluid is inefllciently utilized. In either of the above cases the interrupting operation becomes uncertain and variable.

By providing, outsideof the pressure chamber, a passageway closely confining the movable .contact and the arc,and by providing a flow of fluid through other passageways to chambers communicating with the passageway in which the arcing takes place, an efllcient flow of fluid is easily produced and the interrupting operation is rendered rapid and certain.

It is therefore among the objects of the present invention to provide an electric switch of the pressure chamber type in which the moving contact and the arc terminating thereat are closely conflned'within an arcing passageway.

Another object of the present invention is to provide an electric switch of the pressure chamber type in which the passageway confining the arc is in communication with chambers receiving are extinguishing fluid only during interrupting operation of the switch. e

Another object of the present invention is to provide an electric switch of the pressure chamber type in which the arc extinguishing fluid is vaporized by the are at a plurality of points in the arc path.

Another object of the present invention is to provide an electric switch of the pressure chamber type in which a flow of arc extinguishing fluid is produced under pressure resulting from striking of the arc.

Another object of the present invention is to provide an electric switch of ,the pressure chamber type in which the flow of arc extinguishing fluid is obtained partly by movement of pump means controlled by the movable contact.

Objects and advantages other than those above described will be apparent from the following description when read in connection with the accompanying drawing, in which:

Fig. 1 is a. vertical cross-sectional view of one embodiment of the present invention in which the arc extinguishing fluid is displaced under a pressure generated. by vaporization of a portion of such fluid in the arc; and

Fig. 2 is a vertical cross-sectional view of another embodiment of the present invention in which displacement of the arc extinguishing fluid is obtained partly by means of a piston moving in the pressure chamber of the switch.

Referring more particularly to the drawing by characters of reference, reference numeral 6 designates a. vessel forming a pressure chamber 1 for an electric switch and containing a body of arc extinguishing fluid 8. Vessel 1 contains the fixed contact structure 9 of the-switch, which may be of any suitable kind known in the art and which is provided with suitable conductive connections (not shown) for the purpose of completing the electric circuit of the switch. Contact 9 is immersed in the fluid preferably in close proximity to the surface thereof. A movable con tact l I, preferably of a rod shape, closes the circuit of thebreaker by engaging with contactsand may be guided and operated by any well known mechanism (not shown). when the switch is in the closed position and contact it engages with contact 9, contact H is surrounded over a substantial portion of the length thereof by a member I2, preferably constituted of insulating material, and provided with a passageway l3 closely confining contact ll without however hindering movement thereof. Member I! is supported in flxed relation with respect to vessel 6 in any suitable manner, as for instance by cementing member l2 into a. flange l4 constituting a cover for vessel 0.

- Member I2 is provided with one or more chambers it which are in communication with passageway l3. Some or all of chambers l6 are connected with chamber 1 by means of passageways l'l likewise provided in member i2. Such connection may be eifected in any desired manner; for instance, as illustrated in Fig. 1, some .of chambers l6 may be provided with individual passageways whereas others may communicate with a common passageway and others may be entirely without communication with the chamher 'l. Member i2 is also preferably provided with an extension forming a circular partial partition l3 immersed in fluid 3, whereby passages i3 and II are sealed against-direct connection therebetween through chamber 1. Member l2 may be formed from a single piece of material shaped to provide passageways i3 and i1, chambers i 6 and is formed with partition l3. As illustrated in Fig. 1, member l2 may also be constituted of a body i3 havinga recess receiving a plurality of inserts such as 2i which deflne passageway I3 and chambers l6. Passageways I'I may then be provided between body l3 and the several inserts contained therein. Partition l3 may be integral with the lowest insert. The in-..

serts may be fastened within body i3 by any suitable means' such as by means of a split collar 22 provided with apertures alined with passageways II. When it is desired to provide sufflcient fluid for a number of successive operations of the switch and at the same time insure that the fluid level within the chamber remain substantially constant even with a reduced amount of fluid within the pressure chamber, such chamber-is provided with. a reservoir 23 communicating therewith. Such communication is preferably effected through a relief valve 24 permitting flow therethrough and to flll chambers i3. Contin-' of fluid from chamber 1 into reservoir 23 when the pressurewithin the chamber is excessive, such valve being provided with a vent 26 permitting the slow flow of fluid therethrough to equalize the fluid levels in chamber 1 and in reservoir 23. Reservoir 23 may be closed by means of a cover 21 to avoid evaporation of the fluid and introduction thereof of foreign matter; such cover may be provided with a flller opening closed by'a vented plug 23. I

To cause interrupting operation 01' the switch,

contact i I is moved upwardly out of engagement withcontact 3 and is withdrawn from vessel 6- ued movement of contact ii causes the are between the contacts to be gradually extended over part or all or the'length of-oassageway l3. During suchmotion, contact Ii successively passes through the diflerent chambers iland the fluid v then present in such chambers flows, by gravity, into the arc path at a plurality of points thereof where such fluid is vaporized by the heat of the arc. The arc is thereby deionized and caused to be extinguished, and the excess fluid present in chambers it at the end of the interrupting operaosaaaa ation is returned into chamber I by gravity. During such operation, fluid is forced from chamber I into reservoir 23 through vent 26, but such flow is practically inappreciable as a result of the small dimensions of vent 26. Ii, however, 5 the pressure within vessel 6 reaches a value which might damage anyuif' the portions of the switch, valve 24 opens and permits a substantial flow oi fluid from chamber 1 into reservoir 23 thereby relieving the excess pressure within the chamber.

When the switch is ,being reclosed, contact ll penetrates into passageway i3 and into chamber I and immerses in fluid 3 before engaging with contact 3. Contacts 3 and ii are thus connected by fluid 8'during a length of time which is however inappreciable as a result or the location of contact 3, and any vapor produced by the flow 01' current between the contacts through the fluid will be negligible in amount.

In the embodiment illustrated in Fig. 2, contact 3 is provided with a passageway extending therethrough and is supported within vessel 6 from the side walls thereof. The lower portion of vessel 6 constitutes a cylinder receiving a piston 23. Such piston is biased upward by means of a spring 3! resting on a closure plate 32 separating chamber I from reservoir 23. Piston 23 is provided with a valve 33 permitting flow oi fluid from the lower side to the upper side thereof within chamber 1, and closure plate 32 is likewise provided with a valve 34 permitting flow of fluid from reservoir 23 into chamber 1. Such valves are therefore operable to permit the flow of fluid from reservoir 23 into chamber 1 upon reciprocating motion of piston 23, such motion. being effected by the combined actions of contact ii and spring 3| on the piston. In the present embodiment, member i2 is constituted of a plurality of alined annular members such as disks 36 defining the passageways i3 and I1 and the chambers I6. Members 36 are maintained in engagement with each other and with the upper portion of vessel 6 by means of a spring 31 maintained under pressure by suitable means. Such means preferably comprise a cover 33 mounted on an insulating bushing 33 cemented into a flange 4i, such assembly constituting a cover for reservoir 23. Reservoir 23 may be provided with a level gauge 42 having a filler cap 43 and need not be vented due to the clearance between con- 50 tact ii and cover 33.

When contact ii is withdrawn to cause interrupting operation or. the switch, such contact initially slides through contact 3 while remaining in conductive engagement therewith. Spring 3i then causes piston 23 to move upward, thereby forcing flow of fluid through passageways I! to chamber i6. Fluid is then also drawn from reservoir 23 through valve 34 into the lower part of chamber I. Continued movement of contact il causes such contact to disengage from contact 3 whereby an arc is struck between the contacts 3 and contact I I. Such arc-causes continued displacement of fluid 3 in the manner above described with respect to the embodiment illustrated in Fig; 1, thereby cooperating with piston 23 in causing the transfer or fluid. During such operation, some of the-vaporized fluid condenses within cover 33 and bushing 33 and is returned to reservoir 23, the unvaporized portion of the fluid returning to chamber I by gravity. Piston, 23 is then abutted against the supports of contact 3, thereby raising the fluid level within chamber .1 above that oi. reservoir-.23. 'Fluid will then flow from chamber I through vent 23 into reservoir aosacsa 23 to bring the fluid therein at the same level. During the interrupting operation, excess pres sures in chamber 7 are relieved by means of valve 2%. Excess pressures within passageway l3 and chambers It may cause members 35 to momentarily disengage from each other against the action of the spring 37 to thereby allow vapor in chambers 16 to escape in the space within bushing 39 and thereby relieve the pressure within chamber l5.

When the switch is being reclosed, contact ii penetrates within passageway 13, engages with contact s and depresses piston 29 to the position shown, whereby the fluid present below the piston is transferred to the space above such piston through valve 33 without changing the fluid level within chamber 1.

From the above description of the construction and operation of the present invention, it will be apparent that the displacement of arc extinguishing fluid from the pressure chamber into the arc path is obtained in an efiicient and positive manner at a plurality of points of the arc, whereby the arc is extinguished rapidly and certainly. Closure oi the switch is likewise obtained in a positive and a certain manner even when the are extinguishing rluid is conductive as a result of arranging substantially the entire arc path in air whereby the switch contacts remain perfectly insulated from each other during almost the entire closing operation of the switch.

Although but a few embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

i. In an electric switch, a vessel forming a pressure chamber, an arc extinguishing fluid contained within said chamber, a fixed contact within said pressure chamber immersed in said fluid, a movable contact withdrawable from engagement with said fixed contactand from said pressure chamber, means arranged adjacent said vessel and defining a passageway closely confining said movable contact and defining a chamber in adjacent communication with said passageway, and means for causing said are extinguishing fluid to fill the second said chamber only during interrupting operation of said switch, said means comprising a piston operable in response to movemerit of said movable contact and said means further comprising additional passageways providing communication between a point above said fluid in said pressure chamber and said second said chamber.

2. In an electric switch, a vessel forming a pressure chamber, an arc extinguishing fluid re= talned within said chamber, a fixed contact with-= in said pressure chamber immersed in said fluid and extending adjacent to the surface thereof, a movable contact withdrawable from engagement with said fixed contact and from said pressure chamber, means arranged adjacent said vessel defining a passageway closely confining said mov able contact, a second chamber in adjacent com-- munication with said passageway, and an additional passageway providing communication be tween said second chamber and a point above the surface of said fluid in said pressure chamber.

3.111 an electric switch, a vessel forming a pressure chamber, an arc extinguishing fluid retained within said chamber, a fixed contact within said pressure chamber in said fluid and extending adjacent to the surface thereof, a inevable contact withdrawable from engagement with i said fixed contact and from said pressure chamber, insulator means arranged adJecent said vessel and having a passageway closely confining said movable contact and having a chamber in communication with said passageway, and means for causing said are extinguishing fluid to enveiop said movable contact in the second said chamber only during interrupting operation of said switch, said means comprising a second passageway between said pressure chamber and said first mentioned passageway.

i. In an electric switch, a vessel forming a pressure chamber, an arc extinguishing fluid retained within said chamber, a fixed contact within said pressure chamber in said fluid and extending adjacent to the surface thereof, a movable contact withdrawable from engagement with said fixed contact and from said pressure chamber, means arranged adjacent said vessel and having a'passageway closely confining said movable contact and having a plurality of closed chambers in communication with said passageway, and means for causing said are extinguishing fluid to envelop said movable contact in at least some of said plurality of chambers only during interrupting operation of said switch, said means comprising a plurality of additional passageways providing communication between said some of said closed chambers and said pressure chamber.

5. In an electric switch, a vessel forming a pressure chamber, an arc extinguishing fluid retained within said chamber, a fixed contact inrrnersed in said fluid within said pressure chamber and extending adjacent to the surface thereof, a movable contact withdrawable from engagement with said fixed contact and from said pressure ch rnber, a plurality of contiguous annular members arranged adjacent said vessel and aimed to form a passageway closely confining said rnovable contact and forming a plurality of closed chambers in adjacent communication with said passageway, means including additional passageways provided between certain of said closed chambers and said pressure Ehamber for causing said are extinguishing fluid to envelop said movable contact in at least some oi said plurality of chambers only during interrupting opera tion of said switch, and resilient means yieldably maintaining said annular members in contacting engagement when the pressure within said passageway remains below a predetermined value, said annular members momentarily disengaging when interrupting operation causes the pressure within said passageway to reach said predetermined value.

6. In an electric switch, a vessel forming a pressure chamber, an arc extinguishing fluid retained within said chamber, a fixed contact linmersed in said fluid within said pressure chamher and extending adjacent to the surface thereof, a movable contact withdrawable from engagement with said fixed contact and from said pressure chamber, means arranged adjacent said vessel and having a passageway closely confining said movable contact and having a chamber in adjacent communication with said passageway, said chamber and passageway being connected with said pressure at a point above the level of said fluid, means for causing arc ex= tinguishing fluid to be connected to the second said chamber upon occurrence of a pressure producing are within the first said chamber. and means responsive to movement of said movable contact and cooperating with the last said means to displace said are extinguishing fluid.

7. In an electric switch, a cylindrical vessel forming a pressure chamber, a resiliently biased piston closing said chamber, a reservoir for are extinguishing fluid, valve means operable to cause transfer of arc extinguishing fluid from said reservoir to said pressure chamber by reciprocating motion of said piston, a fixed contact within said pressure chamber, a movable contact extending aoeaass through saidfixed contact against said pie and withdraw/able from engagement with d fixed contact and with said piston and from said pressure chamber, and means arranged adja= cent said. vessel and having a passageway receiving said movable contact and constituting an arcing chamber thereior, said passageway being connected'with said arcing chamber by passageways entering said pressure chamber at a point above the level of said fluid whereby said piston causes flow of arc extinguishing fluid from said pressure chamber into said passageways only in response to withdrawal of said movable contact.

' JAKOB KOPOTGH.

"It i WANG.

CTIFlCATE OF CORRECTION.

Patent No. 2,052,232.

the above numbered patent requiring correction as follows:

August 25, 1936 JAKOB KOPELIOWITGH, ET AL.

It is hereby certified that error appears in the printed specification of Page 4, first column, line 2, claim 6, for "oonnected" read conducted; and that the said Letters Patent should be read with this correction therein that the same may conform to' the record of the case. in the Patent Office.

Signed and sealed this 6th day of October, A. D. 1936.

(Seal) Henry Van Arsdale Acting Commissioner of Patents.

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