US2097406A - Mercurial electrical cut-out - Google Patents

Mercurial electrical cut-out Download PDF

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Publication number
US2097406A
US2097406A US5110A US511035A US2097406A US 2097406 A US2097406 A US 2097406A US 5110 A US5110 A US 5110A US 511035 A US511035 A US 511035A US 2097406 A US2097406 A US 2097406A
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mercury
current
mercurial
paths
cut
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US5110A
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Jenkins Francis Thomas
Sparks Stephen Dale
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H87/00—Protective devices in which a current flowing through a liquid or solid is interrupted by the evaporation of the liquid or by the melting and evaporation of the solid when the current becomes excessive, the circuit continuity being reestablished on cooling

Definitions

  • 'I'he present invention relates to mercurial electrical cut-outs, that is to say, to cut-outs of the type wherein the current to be controlled is passed through a fuse consisting of a column of mercury, a portion of which, on the current exceeding a predetermined value, is vaporized by the heat generated therein due to its electrical resistance, mercury being thereby expelled from the column the continuity of the circuit being accordingly broken.
  • these alternative paths have different external connections, e. g., electrodes connected to a two way switch, so that the flow of the current is not re-established until such switch or the like is actuated, but in certain cases it may be desired that the circuit should be reestablished after rupture with only a minimum time lag, such as is aorded by the change of t paths, and in such cases the provision of dif- I forms pressure was exerted on rubber balls, dia-Y (Cl. D-113) ferent external connections becomes unnecessary or arrangements may be made for temporarily bridging such connections.
  • dia-Y Cl. D-113
  • this invention enables mercury cut-outs to be constructed in which the mercury is hermetically sealed from access of air and this is of great importance since any exposure of the mercury to atmosphere renders it liable to oxidation, which would affect the electrical resistance of the circuit.
  • means may be provided for providing one or more supplementary circuit-breaking points in series with the mercury fuse.
  • the apparatus comprises a cylinder containing mercury and tted with a freely movable plunger and two tubes communicating with opposite ends of the cylinder (which constitutes a common reservoir) by means of openings through that one of which, for the time being in circuit, on the passage of excess current, mercury is ejected against the plunger in such a direction as to impel it toward the other opening through which mercury is therby forced to complete the column in the corresponding tube.
  • a plunger is dispensed with, the communication between the two tubes being such as to permit mercury expelled from one tube to pass to the other, and in a further convenient form one mercury column is used having branch tubes communicating therewith, the mercury being expelled through either one of such branches whilst the other is occluded in order to make a gap in one path for the current through the device and to bridge a gap in another path.
  • the mercury column is of uniform cross section, it will be appreciated that this is not necessarily a feature of the invention.
  • the column is reformed under the simple action of gravity, which would obviously be insufilcient for this purpose if tubes with capillary restrictions were used unless there was a considerable head of mercury above the capillary restriction, and it must be understood that where it is desired to use such tubes the apparatus must be so formed and/or dimensioned that the pressure necessary to reform the column will be available.
  • Figure 3 is a longitudinal section of a modicatlon
  • Figures 4 and 5 are respectively a cross section on line 4 4 of Figure 6 and a iront4 elevation of a further form of cut-out,
  • Figure 6 is a section on the lines 5-6 of Figure 4,
  • Fig. 7 is a longitudinal section of a modied form of cut-out.
  • Fig. 7 is a longitudinal section of one-half of a cut-out similar to that shown in Fig. 7 but on an enlarged scale to show the rled construction of the plunger and cylinder.
  • Figs. 8 and 9 are longitudinal sections of two further modifications.
  • Figures 10 and 11 are respectively a longitudinal section and arsectional plan oi still another form of cut-out.
  • acylinder I constituting the reservoir is made of conductive material and is mounted with its axis substantially horizontal.
  • 'I'he tubes 2 and 3 of ceramic non-conducting material, are substantially vertical and project through the peripheral wall ofthe cylinder I in proximity to its opposite ends.
  • the bore of each tube communicates with a small chamber 4 in a block 5 of insulating material tted in the end of the cylinder I, these chambers communicating with the cylinder by means of passages 6 opening respectively into the chambers at a level somewhat above the point at which the bore of the tube 2 or 3 enters the chamber and extending in a downward direction toward the cylinder I, as shown.
  • Either the chamber 4 (as shown) or the passage 6 is lined with conducting material 4a which serves, when the mercury column is complete as indicated within the tube 3, to establish electrical connection between it and the cylinder I or the mercury contained therein.
  • a plunger 1, freely movable in the cylinder I is located between the outlets of the passages 6; thus, on mercury being ejected from one of these passages due to rupture of the mercury column in ⁇ the tube'2 or 3 communicating therewith, suicient pressure is exerted on the plunger I to impel it toward the opposite end and thus force mercury through the passage 6 in the opposite insulating block 5 and thence, via the small chamber 4, into the corresponding ceramic tube, thereby completing the column therein.
  • the lower ends of the ceramic tubes 2 and 3 are respectively tted in blocks 8 of conductive material provided with pinfconnections 9, terminals or other suitable means ffor connection to the external circuit.
  • the ends of the cylinder I are closed by plugs I0, to one of which there is fitted a pin connection I Iy or the like.
  • the whole apparatus is enclosed in a moulding I2 of the material known by the registered trade name Bakelite or other suitable substance, the terminals or "the like projecting therefrom.
  • the lower end of 'the lining to chamber 4 terminates so far short of the bottom of block 5, that if the column rey makes other than by the rupture ot the other column, the level of the mercury falls below the lining and maintains the interruption of the circuit.
  • connections are led from the pins or terminals 9 to a two-way switch I3, represented diagrammatically, the main circuit being connected, as shown, to the common terminal of this switch and to the terminal II.
  • the two-way switch may be of any suitable form and may be either separate from the cut-out itself or incorporated with or attached to the Bakelite or like moulding.
  • each indicator which, as shown, is preferably of the type described in U. S. A. patent application Serial No. 642,123, consisting of a tube I4 filled with neon or other suitable gas and connected respectively between the cylinder I and the corresponding plug 8.
  • the tubes I4 are thus respectively in parallel with the mercury columns, and when either column is ruptured, an indication 'of this fact is aiorded by the glowing of the corresponding tube.-
  • the tubes I4 are housed in a cavity within .the Bakelite or like moulding. and are viewed through apertures I5 located opposite the tubes.
  • the various parts of the apparatus are so dimensloned, and the amount of mercury inserted is such that, as indicated, one of the mercury columns is complete while the other is ruptured; consequently, when it is desired to introduce the cut-out into circuit the two-way switch I3 is turned to the position shown communicating with the complete mercury column which'then carries the current. On rupture of this column the circuit through it is broken, the force of the rupture being employed to complete the other column as above described. The complete circuit is, however, not immediately re-established, this action only taking place when the two-way switch is moved to the position in which connection is made between its common terminal and that communicating with the second mercury column.
  • the mercury columns shall occupy a vertical position: for instance, in the alternative construction of cutout depicted in Figure 3 the ceramic or like tubes 2 and 3 ⁇ are substantially co-axial with the cylinder I constituting the common reservoir and are fitted into its ends.
  • the blocks at the ends of the cylinder I and indicated at 5a are of conductive material and the passages 6a slope upwardly toward the interior of the cylinder so that on rupture of one of the columns, a small quantity of mercury is trapped in the corresponding passage: this serves to make contact with the main body of the mercury contained in the cylinder I when, on rupture of the opposite column, a plunger 1a travels along the cylinder so as to cause the mercury level to rise and ll the inclined passage and the ceramic tube communicating with it.
  • the plunger 'la may be made in the form of a ball, and the pins or the like 3 and II may be carried by 'spring clips which grip around the member with which they make contact.
  • the two ceramic tubes 2 and 3 wherein rupture occurs are combined into asingle tube I6, the altemative-paths, essential in accordance with the ⁇ present invention, being provided by branches I1 and I3 having linings of conductive material and communicating with the interior of cylinder Ia whose wall is made oi non-conducting material.
  • the plunger 1b within the cylinder Ia is of conducting material and, as shown, is provided with three heads, these being so spaced that when the plunger is in either of its extreme positions one of the branches I1 or I8 is occluded by the central head.
  • Thecylinder Ia is provided over portions o!
  • the ceramic tubes 2 and 3 are maintained separate and are electrically connected to the cylinder Id o! the insulating material by means of conducting blocks 2i, 22 provided respectively with insulating sleeves 23, 2l constituting cylinders for pistons 25, 23 the rodslof which are pivoted to a rocking lever or levers 21 and electrically connected with the terminal II.
  • the plunger 25 is in contact with the block 2
  • the plunger 25 descends, thus coming into contact with the conducting block 22 and forcing mercury into the tube 3 to re-establish the mercury column therein.
  • a plunger in the cylinder or associated with the mercury columns is by no means essential, and in Figures 9, and 11, two forms of cut-out are illustrated in which the plunger is dispensed with.
  • the cylinder le which in this case is of insulating material, is provided with a lining 28 of conductive material, the base of which is formed with an excrescence 29 which permits mercury to collect either on one side or the other.
  • the mercury column in the ceramic tube 2 being shown as completed, when it is ruptured mercury is thrown over the excrescence 29 to the space above the tube 3, which is thereby filled ready for use when the switch I3 is changed over to its contact connected therewith: likewise, on rupture of the columns in the tube 3, the mercury is thrown back over the excrescence 29 tothe space above the tube 2, thereby filling that tube ready for use when the switch I3 is changed back again.
  • the ceramic tubes 2 and 3 communicate respectively with chambers 30, 3l having metallic liners connected with the common terminal II by a metal plate 32.
  • Inclined passages 33 and 34 and cross passages 35 and 36 respectively connect the chambers, so that, on ejection of mercury from one of the tubes e. g., 3 (in which a momentary rupture is indicated), it ilows along the passages 33, 35 or 34, 35, as the case may be, to reach the other tube which is thereby illled with mercury. It will be understood that no passage of current can take place by mercury ilowng back to this tube since the level will be too low to reach the conducting liner 3
  • the additional cut-out capacity may be equal to or smaller than the main cut-out, the two together providing for a temporary increase in capacity.
  • this can be eiected by bridging the pins, terminals, or connections that are normally connected to the two-way switch I3, thus dispensing with the latter by theiprovision of a pivoted arm I3a, as shown, for example, in Fig. 7, or by the use of a pull-off bar or bridging the gap by means of an ordinary wire.
  • the ceramic tubing may with advantage be provided :with a series of external vannular ribs and grooves which inter alia provide a better grip for the covering material and also assist in heat dissipation.
  • I f a series of external vannular ribs and grooves which inter alia provide a better grip for the covering material and also assist in heat dissipation.
  • the cut-out may be initially charged by anyl convenient method, e. g., by connecting the mercury column tube or one of such tubes to a vacuum pump and allowing the mercury, stored for examplel at atmosphericpressure to iiow into the exhausted cut-out through such tube.
  • 'I'he second column where this is provided may be formed or completed by establishing a rupture of the. column already made.
  • a tube lconnecting the column tube with the pump may be pinched or fused to seal oil.' the device.
  • the charge introduced into the cut-out is of such an order that upon such a rupture occurring the required a'mount of mercury is available for establishing the column in the other tube.
  • the ⁇ parts of the apparatus not lled by the mercluy may be exhausted of air or charged with a nonoxidizingl gas.
  • a space for expansion of the mercury, which is ejected is provided.
  • the expansion space isformed by the cylinder I and the chambers or passages communicating with it; in Fig. 7 an expansion space is formed by the cylinder I; ih Fig. 8 the space formed below the ⁇ piston when in raised position serves as an expansion space; in Fig. 9 the cylinder I and in Figs. 10 and l1, the chambers 3l and the passages 33, 34, 35 and 36 form the expansion space.
  • a mercurial electric cut-out provided with two tubes containing mercury columns, said tubes being contained in alternative 'paths for the passage of the current through the apparatus, a common reservoir with which both said tubes communicate, said reservoir being constituted by a cylinder provided with a plunger whereby when one said path is broken by the expulsion of mercury from one said tube by the current under control exceeding a predetermined value, the expelled mercury causes the plunger to move and displace mercury into the other tube so that the other of said alternative paths is automatically -made available for the passage oi' the current.
  • a mercurial electric cut-out provided with a single tube provided with branches contained in alternative paths for the passage oi' the current through the apparatus, a cylinder with which both said branches communicate, and a plunger arranged in said cylinder so that when one said path is broken by the expulsion of mercury from said tube and one said branch by the current under control exceeding a predetermined value, the plunger is displaced by the expelled mercury and caused to make available for the passage of the current the other of said alternative paths, said plunger being provided with three heads and being so dimensioned that when it is in either of its extreme positions one of the branches is occluded by the central head and the other branch opens into the space between the central head and that at one end of the plunger.
  • a mercurial electric cut-out provided with a single tube provided with branches contained in alternative paths for the passage of the current through the' apparatus, a cylinder with which both said branches communicate and a plunger in .said cylinder, said cylinder and plunger beingcorrespondingly riiied and said plunger being arranged so that when one said path is broken by the expulsion of mercury from said tube and one said branch by the current under control exceeding a predetermined value, the
  • plunger is displaced by the expelled mercury and caused to make available for the passage of the current the other of said alternative paths.
  • a mercurial electric cut-out containing alternative paths for the passage of the current through the apparatus and at least one supplementary circuit breaking point provided in series with the mercury forming part of each path, piston means controlling the opening and closing of said supplementary breaking point, a cylinder in which said piston means are arranged, said cylinder communicating with the mercury containing part oi.' the cut-out so that the piston means are actuated by the mercury expelled when the current exceeds a predetermined value, said piston being arranged so that when it is so actuated it renders available an alternative path for the current through the apparatus.
  • Amercurial electric cut-out containing alternative mercurial paths for the passage of the current through the apparatus, said paths being arranged so that any one of said paths which for the time being is closed includes a mercurial fuse which is adapted to rupture when the cui'- rent passing through it exceeds a pi edetermined value and means whereby on rupture occurring of the circuit along one path mercury expelled from said fuse automatically renders available an alternative path through the apparatus, said al- ⁇ ternative path including said mercurial fuse which allows the current to pass in such latter path so long as said current does not exceed a predetermined value.
  • a mercurial electric cut-out containing a plurality of mercurial fuses each adapted to rupture and break the circuit when the current passing through it exceeds a predetermined value, expansion space between said fuses, alternative paths for the passage of the current through the apparatus each containing one o1' said fuses, said paths being arranged so that when the current under control exceeds a predetermined value mercury is expelled from the fuse in the path for the time being closed and passes directly to another of said fuses so as to re-make the said last mentioned fuse and automatically render an alternative path available for the passage o! the current through the apparatus.
  • a mercurial electric cut-out provided with two tubes containing mercury, an expansion chamber between said tubes, said tubes being substantially parallel with each other and in communication with opposite ends of said expansion chamber, said mercury-containing tubes being in different paths for the current through the cut-out and being arranged so that when the path of the current through the mercury in one tube is interrupted by the expulsion of mercury from vthat tube, mercury is caused to enter the other tube and render available the other path for the current, the mercury in each tube thereby in turn serving as a fuse to inten'upt the circuit through the cut-out when the current passing exceeds a predetermined value.
  • a mercurial electric cut-out provided with two tubes containing mercury, said tubes being contained in alternative paths for the passage of the current through the cut-out, a common reservoir with which said tubes communicate, said tubes being substantially in line with, and in communication with opposite ends of, said reservoir, said reservoir being constituted by a cylinder provided with a plunger whereby when one of said paths is broken by the expulsion of mercury from one said tube by the current under control ex.
  • the other of said alternative paths is automatically made available for the passage of the current by the expelled mercury indirectly causing the column of mercury in the other of said tubes to be completed.
  • a mercurial electric cut-out containing alternative mercurial paths for the pasage of the current through the apparatus, said paths being arranged so that the one of said paths which for the time being is closed includes a mercurial fuse which is adapted to rupture and break the circuit when the current passing through it exceeds a predetermined value, and means whereby on rupture occurring of the circuit along one path mercury expelled from said fuse automatically renders available the alternative path through the apparatus, said alternative path then containing the said mercurial fuse which allows the current to pass so long as the current does not exceed a predetermined value, each of said paths containing at least one supplementary circuitbretililking point in series with the mercury in the pa Y l2.
  • a mercurial electric cut-out containing alternative paths for the passage of the current through the apparatus said paths being arranged so that any one of said paths which for the time is closed includes a mercurial fuse which is adapted to rupture and permit the expulsion of mercury therefrom when the current passing through it exceeds a predetermined value, and means whereby on rupture occurring of the circuit along one path mercury expelled from said fuse automatically renders available an alternative path through the apparatus, said alternative path containing a mercurial fuse which allows the current to pass so long as the current does not exceed a predetermined value, in combination with switching means which require to be actuated before the current can pass through the available alternative path.
  • a mercurial electric cut-out containing at least three contacts within a sealed space, two interior paths for the passage of the current through the apparatus between said contacts, said paths being arranged so that4 any one of said paths which for the time being is closed includes a mercurial fuse contained within said space, means whereby when that path is broken by the expulsion of mercury therefrom by the current under control exceeding a predetermined value,y
  • the other of said paths is automatically made available for the passage of the current, a twoway switch, connections external of said space between said contacts and said switch, said switch requiring to be actuated before the current can pass ⁇ through such other path, said other path when switched in serving to pass the current under control until the current again exceeds a predetermined value, whereupon that path is broken by the expulsion of mercury therefrom and the nrst mentioned path automatically made again available for the passage of the current.
  • a mercurial electric cut-out provided with alternative paths for the passage of the current through the apparatus, each path comprising a tube containing a mercury column adapted to rupture and'break the circuit when the current passing through it exceeds a predetermined value, a common expansion chamber between the tubes ⁇ with which said tubes communicate, and means whereby when one said path is broken by the expulsion of mercury from one said tube by the current under control exceeding such predetermined value, another of said alternative paths is automatically made available for the passage of the current by the expelled mercury causing the col- I umn of mercury in another of said tubes to be completed, the mercury in said last mentioned tube allowing the current to pass in said last mentioned alternative path unless saidcurrent again exceeds a predetermined value.
  • a mercurial electric cut-out containing alternative paths for the passage of the current through the apparatus, each of said paths containing a mercurial fuse which is adapted to rupture when a current exceeding a predetermined value passes therethrough, a sealed space in the interior of the cut-out for containing the mercury and providing an expansion space therefor, contacts within said sealed space dening said alternative paths therethrough, the contacts of said paths at one end at least of said paths being separated from each other, one of the paths between said contacts being normally broken and.
  • a mercurial electric cut-out according to claim 1'7 having exterior contact faces communieating electrically with said interior contact faces.
  • a mercurial electric cut-out containing alternative paths for the passage of the current through the apparatus, said paths being arranged so that any one thereof which for the time being is closed includes a mercurial fuse which is adapted to rupture when a current exceeding a predetermined value passes therethrough, and an element movable by the mercury expelled as a result of a rupture for automatically causing another of said paths to be made available for the passage of the current, said alternative path containing a mercurial fuse which allows the current to pass so long as it does not exceed a predetermined value.
  • a mercurial electric cut-out provided with a single tube containing mercury, branch tubes from said tube contained in alternative paths for the passage of the current through the cutout, a contact member for each path, a common reservoir with which both said branch tubes corn-l municate, the column of mercury contained'in said single tube serving as a fuse which ruptures when the current exceeds a predetermined value, said fuse being contained in whichever-path is for the time being closed, a movable elementin said reserteir adapted to be displaced by mercury expelled from saidcolumn when a'current overload occurs, the movement oi'V said element causing electrical *connection to be broken at one of said contacts and made at another and serving to displace mercury back into ⁇ the single tube so as to make the latter again available for use.
  • a mercurial electrical cut-out containing alternative mercurial paths for the passage of the current through the apparatus, said mercurial paths being arranged so that any one of said paths which for the time being is closed includes a mercurial fuse which is adapted to rupture when a current exceeding a predetermined value passes therethrough, said mercurial paths being contained within a sealed space in the cut-out, means whereby when any one of said paths is broken by the expulsion of mercury therefrom another of said paths is automatically made available for the passage of the current, said alternative path containing a mercurial fuse which allows the current to pass so long as it does not exceed a predetermined value, and external contacts communicating with said paths and adapted for connection with diil'erent electrical paths external to such mercurial paths.
  • a mercurial electrical cut-out comprising a plurality of mercurial electrical fuses, an expansion chamber between said fuses, a sealed interior within which said fuses and said expansion space are contained, exterior contacts, current-conducting lines within said interior connecting said contacts and providing alternative current paths, each line containing one of said fuses, one of said fuses being normally arranged so that the line therethrough is broken and another of said fuses being arranged to complete another of said lines, said latter fuse being adapted to be ruptured when the current passing through it exceeds a predetermined value.
  • said fuses being arranged so that when the one in circuit ruptures due to a current overload mercury is caused to ow into and complete another fuse, and means for preventing mercury from returning to the ruptured fuse and remaking the corresponding line.

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US5110A 1934-02-09 1935-02-05 Mercurial electrical cut-out Expired - Lifetime US2097406A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4395/34A GB438190A (en) 1934-02-09 1934-02-09 Improvements in or relating to mercurial electrical cut-outs

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US2097406A true US2097406A (en) 1937-10-26

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US (1) US2097406A (enMihai)
BE (1) BE407673A (enMihai)
FR (1) FR798476A (enMihai)
GB (1) GB438190A (enMihai)
NL (1) NL41953C (enMihai)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2505193A (en) * 1946-02-08 1950-04-25 Loporto Frank Fuse plug

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2505193A (en) * 1946-02-08 1950-04-25 Loporto Frank Fuse plug

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NL41953C (enMihai)
FR798476A (fr) 1936-05-18
BE407673A (enMihai)
GB438190A (en) 1935-11-11

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