Патент USA US2132920код для вставки
Oct. 1l, 1938. I ` P. s'. BEAR Er'AL ' swITcH _' ‘ ' `2,132,920 , Filed Aug. 5, A1935 - 2 Sheets-sheet 1v ' Oct. ll, 1938. P. s. BEAR Er AL swITcH Filed Aug. 5, 1935 2,132,920 ' 2 Sheets-Sheet 2 2,132,920 Patented Oct. 11, 1938 , UNITED vSTATES PATENT OFFICE swrron y Paul S. iìear and Herbert EÍ Bucklen, Elkhart, Ind., assignors to Bucklen-Bear Laboratories, Inc., Elkhart, Ind., a corporation of Indiana Application `August 5, 1935, Serial No. 34,682 (Cl. 20o-_152) 26 Claims. Our invention is concerned primarily with switches of the mercury contactor type, and par ticularly with switches having a metallic switch envelope in place of the glass type envelope for 5 merly employed. which has sealed-in metallic electrodes, although certain features of the pres ent invention are applicable to such glass en velope switches. A - The specific embodiments herein disclosed ,are l0 heavy duty switches suitable for a heavy schedule of switching- of power current. While our inven tion is especially useful for heavy duty switches, certain phases of the invention are equally ap plicable to light duty or small capacity switches. l5 In mercury switches of the glass envelope type, the envelope is either evacuated or provided with a filling of hydrogen, neon, or a similar gas, usually under pressure. There are distinct dis advantages in both types of glass envelope 20 switches, since the inability to dissipate heat re sults in excessive temperature of the inleads'A with resultant leakage about the seal. Such leak age admits oxygen to the interior of the envelorîe, resulting in rapid deterioration of the switch. or 25 explosion of the hydrogen filling. to permit inñltration of air, causing oxidation of the inner surfaces of the shells. ' ì Attempts have been made to fill suchswitches with hydrogen gas, but hydrogen gas is very dif ficult to retain. Hydrogen will leak through pores 5 that will not pass other gases. It has also been attempted to employ liquid ñlls in such switches, but thus far no commercially practicable liquid fill switches have appeared on the market or been available. We have found that liquid iilled 10 switches prior `to our present invention would almost invariably explode upon continued inter "rupting operation at their rating, or upon over load. Our present invention contemplates a mercury 15 switch of the sealed envelope type, in which the interior of the- switch envelope is cleaned thoroughly prior to assembly, and kept clean dur ing operation. In the preferred form of our in vention we employ a cup-shaped metallic shell 20 which has a ceramic insert sealed in one end thereof and having an electrode carried thereby,_ the shell itself serving'as the second electrode. In order 'to reduce the localization of heat generated by the arcing produced during opening 25 The chief disadvantage of glass envelope ' and closing of the switch as much as possible, we switches of the mercury type is that there is a .4 provide a switch construction in which this gen considerable difference in the coeilicients, of thermal expansion of the glass and of the' me-. eration of heat takes place away from the metallic switch parts. 'I'his greatly reduces the tendency 30 tallic electrodes. vThis results in a definite limi tation of the size of the electrode that can -be for pitting and oxidation of the metal. This con- 30 struction also secures the beneficial action oi’ employed, directly limiting the current carrying capacity of the switch, since heating of the elec a mercury to mercury making and breaking of the contact. Also, our present construction re moves this generation of heat as far as possible from the point of sealing of the ceramic insert 35 trode produces severe strains in the glass sur 35 rounding its point of entrance into the switch, and in most cases results in loosening of the seal or into the open end of the shell, serving to protect cracking of-the envelope, both of which results this seal from the heat. are disastrous to the life of the switch. ' This has induced a tendency to use _metallic 1 40 shell type mercury switches, but such construc tions present other disadvantages limiting their use. With a metallic envelope type of switch, there is diiiiculty in keeping the parts free of im purities, and surface oxidation particularly, dur 45 ing the assembling process. Impurities tend to foul the mercury as_well as the contact sur faces, and tend to increase the contact resist ance. Also, where a thin metal section is em ployed, the thermal capacity is low andthe rate 50 of heat transmission is 'limited thereby. In such constructions the heat generated by a rapid suc cession of makingand breaking of relatively high currents cannot be readily dissipated,»causing uneven heating up of the parts and tending to 65 break the seals about the electrodes. This tends Y ' _ One of the primary objects of our present in vention is the use of a liquid iill which is limited in volume with respect to the vapor space in 40 the switch envelope. This limited liquid ñll to vapor relation is of distinct advantage in con nection with several phases of this type of switch construction. In the first place, the liquid iill which dwe preferably employ is a slightly viscous 45 liquid having a relatively high boiling point. The preferred liquid is triethanolamine. We may utilize a mixture of castor oil and alcohol. We do not wish to be limited to the above named liquids as others may be employed but the foregoing 50 appear to 'ne-suitable for this purpose. Only a limited quantity of such liquid is em ployed, the major portion of the interior ofthe switch envelope being employed as a vapor cham ber. Upon slight heating of the liquid iill by 55 2 2,182,920 the making and breaking of contact within the switch, the liquid starts to boil, and the vapor ramic shell type switches; and liquid. modified form of electrode and stud. f respect to the _volume of the chamber produces the beneficial action, that the liquid fill upon boiling v10 and subsequent condensation acts as a highly 15 20 25 - chamber lbecomes filled with vapor which con denses on the defining surfaces of the envelope and runs back as' a liquid into the main body of The use of alimited amountr of liquid lill with ' Figure 8 is a sectional view through a modified type of metal shell switch; Figures 9 and 10 are similar views through ce _ Figure 11 is a fragmentary section through a Referring now in detail to’the drawings, in Figure 1 we have provided _a substantially cup- ' shaped metallic shell I0, having an outwardly flared open end portion I2 adapted to receive the effective medium for dissipating heat generated ceramic insert I3, preferably porcelain of the wet at a localized 'point in the switch uniformly to ' process type; which insert is provided with an all parts ofthe envelope, whereby the heat is outwardly flaring tapered spillway -or runway I4 rapidly conducted away from the arcing point and extending into the shell I0 toward the closed end dissipated throughout the switch. This prevents thereof. The shell I0 is preferably a drawn sheet the temperature at the heat generating point from metal member formed of iron or stainless steel rising above the boiling point so long as `there is I or alloy of iron. liquid in >contact with the heated part. , The insert I3 is provided with an annular disc Another beneficial action secured by the use of or ring member I5 of iron, stainless steel or alloy a relatively large vapor space in the envelope of iron forming an electrode, which member is 20 compared to the amount of liquid ñll employed providedl with a threaded stud I6, also of iron, resides in the limitation of the vapor pressure stainless steel or alloy of iron, extending out which can be generated by converting all of it to wardly through a tapered opening formed sub a vapor. ' ' f v stantially coaxially of the spillway I4 and extend Still another beneficial action secured by this ing outwardly of the ceramic insert I3. The stud 25 limitation ofthe liquid fill resides in the reduction I6 is secured in position to hold the electrode I5 of resistance to movement of mercury contactor, in proper position by means of al washer member since it does not have to displace any appreciable I1 and nut I8 threaded thereon and bearing quantity of liquid during its movement into and , against a suitable resilient conical gasket or pack ing member I9, which is compressed axially in 30 30 out of lcontacting engagement. The use of a liquid ñll of this type is also advantageous in that as order to expand it radially. This gasket or pack the pressure builds up inside the envelope, due to ' ing member I9 preferably is formed of natural the heat of the arc, the arc value is thereby re duced by the increased pressure, preventing the 35 formation of any appreciable’ arcs during rapid operation of the switch. ' or artificial rubber or like impervious expansible material, or any other suitable material. A suit able recess permitting llateral expansion at the outer'end of the conical-packing member 49 may The particular characteristics and advantagesl >b_e provided forkeeping the rubber undercom of liquid fills as to their action on the metallic surfaces and the like are fully disclosed in our 40 copending application, Serial No. 745,842, filed September 28, 1934. Another feature of the present invention 'is the simplified, compact and eflicient switch structure which we employ in connection with the concept 45 of limiting the liquid fillÁ to vapor relation. The structure which we herein disclose is designed to ,utilize the advantages of the limited liquid fill but obviously many, if not all, of the advantages may be realized in other structures or types of struc 50 tures, though generally less in degree. Other objects and advantages of the present invention will appear more fully from the follow pression without completely filling -the available space. . This allows the washer 41 to rest against the ceramic I3. Alternately, the. washer 41 may 40 rest solely upon the end of the rubber gasket 49. ‘ A conductor 20 is soldered or otherwise suitably secured to'the outwardly extending end of the stud I6. . ' » The electrode I5 is disposed within a substan tially cylindrical recess 22 formed at the rear end of the outwardly flaring spillway I4, the re cess 22 providing 'a retaining ring or groove adapted to carry a small body of mercury 23 therein which is in engagement with the elec 50 trode I5, and which is adapted to .have contact ing engagement with a second body of mercury ing detailed description, which, taken in oonnec- _ 24 upon tiltingof the switch to move the body of - mercury 24 up the inclined spillway I into con tion with the accompanying drawings, will dis 55 lclose to those skilled in the art the particular con struction and operation of a preferred embodi ment of our present invention. In the drawings: 22 lprovides a lshoulder, the vedge of _which is - Figure 1 is a vertical sectional view .through one form of switch `embodying the principles of the present invention, the switch hereshown being a‘low angle switch; AFigure 2 is a view similar to Figure 1, through a modiñed type of switch, this switch being a high angle switch; Figure 3 shows the ,switch of Figure 2 in the other of its operating positions; tact with the body of mercury 23. 'I‘he junction of the spillway I4 with the recess ` sharp and includes a solid angle of 'less than 90° whereby accurate repeat perfomance is secured. In assembling the component> parts of the 60 switch, the insert I3, is secured in the :flared end I2 of the shell I0 by means `of a sealing gasket 25, which may be formed of natural or synthetic rubber or other suitable material, and which is compressed partly axially and partly radially and 65 laterally of the tapered surfaces 26 and 21 of the insert when the insert is moved into position Figure 4 is a sectional view taken‘substantially y' within the end of the shell I0. on line 4-.4 of Figure- 2, showing the internal A suitable me tallic retaining ring 21' of frusto-conical section 70 construction of th'e switch; is carried »by the outer end of the insert, and the 70 Figure 5 is a detailed view of a modified type of outwardly defining edge of the flared portion I2 insulating sleeve embodied-in the switch shown in of the shell III-is spun inwardly over the longi tudinally extending end of the gasket 25 and Figures 6 and 7 are corresponding views of 'ring 21', as shown- at 28, vto compress and dis 75 still further modified types of insulating sleeve; place the gasket into final position to seal the 76 Figure 2; _ ' - f , 2,132,920 3 with the relatively cool walls _throughout the re insert within the shell. The spun-over edge 28 serves to prevent displacement of the insert I3 outwardly of the shell i0 by internal pressure. mainder of the switch envelope, is condensed, and runs back down the side wall of the envelope A slight expansion space for the lend of the rub into 'the main body of liquid iill. _ This ebullìtion ber gasket 25 should be allowed near or at ring 21’. of the liquid fill and the subsequent condensa ' The shell I0 forms the second electrode for the ' tion of the vapor, due to the use of a definitely switch, having secured thereto a conductor 29 which may besoldered or otherwise suitably se cured to the external surface of the shell l0, as 10 indicated at 3B. In the assembly of the switch structure shown'in Figure 1, the closed and rounded end 32 of the shell I0 is provided with a threaded‘inward ly extending portion receiving the closing screw 15 or sealing plug 33. When the insert, with its y electrode fixed in position, is sealed within the open end of the shell, the shell is tipped upward ly with the end 32 thereof disposed at the top of the switch, and the mercury 23 and 24, of a 20 predetermined amount, is placed in the switch envelope through the opening closed by the plug 33. A suitable quantity of liquid ñll, indicated at 35, is then forced into the interior of the shell I0, the interior of the shell beingfirst evacuated to 25 produce a relatively high vacuum therein, and being washed in any suitable manner to drive out any occluded gases or the like. Before the liquid fill has been introduced, and with a vac uum in the chamber, the chamber may be filled, 30 preferably under a slight pressure, with any suit-‘ limited quantity of ñll, prevents any excessively high rupturing pressures within the envelope, even if all of the liquid vaporizes. We preferably employ triethanolamine as the liquid ñll, this liquid having a relatively high boiling point and having the characteristic of maintaining the switch surfacesclean and free from foreign materials. If desired, however, a mixture of castor oil and alcohol may- be em 15 ployed, the castor oil being employed in the form commercially known as “_Ricinine”. Any’liquid of this class which is anhydrous, alkaline in re action, possesses arc extinguishing character istics and has about the same viscosity and boil 20 ing point, may be employed. It will also be apparent that the generation of heat at this acute breaking angle will be trans mitted directly to the liquid ñll, and by reason of the vaporization of this liquid fill will be'dissi 25 pated substantially uniformly throughout the `en tire switch envelope, whereby the entire surface of the metallic shell I0 can be used for heat con duction away from-the point of generation of ` heat, whereby the heat will be rapidly dissipated 80 to the surrounding atmosphere. Thus the lim able gas which is substantially inert or non cor-rosive with respect to the metal and with re- ' ited liquid ñll performs three important functions spect to the liquid ñll. This may be neon, argon, nitrogen, carbon monoxide, hydrogen helium, or 35 the like. The amount of liquid fill 35 which is inserted is predetermined with respect to the vol in a switch of this type, namely, a maintenance of a relatively low pressure, less than the ruptur ing or leakage pressure caused by its ebullìtion due 85 to the heat generated by arcing of the mercury ume of the interior of the switch envelope. In a preferred embodiment of the invention the quantity of liquid fill for a switch envelope hav 4.0 ing approximately a 21 cc. volume comprising about 0.5 cc. of liquid iill, which, together with the mercury and the like, provides for approx to mercury contact; secondly, its use as a heat l. 45 the internal volumeof the switch chamber is 21 cc. and approximately 7 cc. of ‘mercury is employ the arcing time, or the length of the arc, de 45 creases. By maintaining the volume of liquid fill transferring medium for dissipating the localized heat generated by thearc within the switch to all points of the switch envelope; and thirdly, the 40 reduction of the arcing time due to the increased pressure within the switch envelopeV caused by evaporation of the fill, whereby upon increased imately 13.5 cc. of vapor space within the cham ber. In a preferred embodiment of our switch, -rapidity of operation the pressure increases and ed as a contactor. The liquid ñll may run any employed relatively small with respect to the vol where from 1/2 cc. to 1 cc., leaving a vapor space ume of the vapor space indicated at 35, it occupy of approximately 64% of the total volume of the We have shown the liquid as exaggerated in amount in the drawings, for the sake of illustration. In practice, the liquid has a tendency to spread and wet all of the inside sur face of the container. The liquid- _film is shown ' ing only about 3% of this volume, it is apparent that high internal pressures within the switch 50 envelope will not be developed even though all, or substantially all, of the liquid ñll be vaporized.' Thus by the limited liquid fill both hot spots which are particularly destructive of glass en velope switches and high' pressures which are de 55 50 switch chamber. 55 as of an exaggerated thickness, for purposes of illustration. ' When the connection tothe opening into which the closure plug 33 extends is removed, a por-v tion of this gas escapes, providing a vapor space 60 above the liquid ñll 35. The closure plug 33 is then immediately screwed into place and the en tire external surface of the switch envelope and the ceramic insert may be coated with a coating of “Bakelite”, cellulose aetate, or the like. 65 .It will be noted, in this embodiment of the in vention, that the making and breaking of con ‘ tact occurs at the acute angle formed between structive of all forms of switches are avoided or greatly reduced. - It is to be observed that our system of internal circulation of the liquid flll is unique. The liquid forms a viscous film in contact with the internal 60 surfaces and particularly with the mercury, which is always subject to heat generation by both the flow of current through it and by the arc produced at either making or breaking of the circuit. This film of liquid is vaporized locally, i. e., at the point where heat is generated. The vapor tends to fill the entire vapor space and selectively the sloping spillway I4 and the side wall defining ‘ flows to the coldest region because it is there most ` ' the cylindrical recess 22. Thus, the heat gen 70 erated is generated at a point removed from the metal itself, and inasmuch as the liquid fill surrounds, or at least wets, this particular point of making and breaking of Contact, the liquid fill is heated to’ an extent such that a portion of 75 it vaporizes. This vapor then comes into contact rapidly condensed. ‘By the employment of a liq uid the boiling point of which is at a substan tially higher temperature than that of the sur rounding air, i. e., by providing a substantial tem perature differential, the heat of vaporization which is given óñ by the vapor in condensing on the inside surfaces is readily dissipated. 'm ' 4 2, 1312,920 _The condensed liquid, being viscous, runs back slowly, and thereby tends to give oif heat in ex cess of the heat of vaporization, i. e., a substantial part of the heat of the liquid. Thus the viscosity rends to regulate the rate of circulation of the iiquid back to the point of heat generation by gravity. The liquid of the thin layer or ñlm is - thus elevated by heat, i. e., vaporization, and de livered to the point'where it liqueñes and returns Thus there is an internal circulation of the liquid in the switch. This action is highly z advantageous, and is particularly useful in heavy duty metal' shell switches. There is a peculiarly useful feature in the con 15 stitution of the liquid flll as above disclosed. The 10 by gravity. high boiling point, viscosity, and the limitation of amount provide an ideal coordination of features, ' for Anot only is the heat easily dissipated, but the rise of pressure is also limited. 20 ` - In the construction ci the porcelain insulator I3 it is advisable to construct the same of two parts joined together because of the 'diñìculty otherwise encountered in producing the sharp an nular shoulder and the annular recess 22. The 25 joint between the two parts is made preferably at a point along the length of the recess 22 where the gasket or seal 25 will prevent any possible leakage of the joint from communicating with the outside; Thus an imperfect joint between the two porcelain parts does not destroy the useful ness of the switch. The parts may be produced and ñred and then cemented together or they may and the head end of the stud 45. A second body of mercury 5.4 forming the rest of the liquid fdl is carried withirrthe shell 40 about> the outer surface of the ceramic sleeve 44, the two bodies of mercury being adapted `to have contacting en gagement beyond the outer end of the ceramic Asleeve 44 when the switch is tilted about its longi tudinal axis. The insert 43 is secured within the open end of the shell 42 in the same manner as described in connection with Figure 1, there being 10 a suitable resilient gasket 55 and clamping ring 55’ interposed therebetween, the outer edge 56 of the shell being spun over the rear portion of the gasket and about the outer surface of the ring to retain the insert in cushioned sealed engage 15 ment within the end of the shell 40 substantially. A second conductor 51 is secured at 58 to the external surface ofthe Vshell 40, whereby control of the circuit through the conductors 55 and 51 is provided by movement of the bodies of mercury 20 53 and 54 within the switch. 'I'he closure plug 59 ~ corresponds, to the closure plug 33 of Figure 1, and is employed in the same manner. A suitable liquid fill 60 is introduced into the interior of the switch’envelope, and is so propor 25 tioned with respect to the vapor space 62 that ‘ free ebullition of the ñll is provided for washingV the'internal surfaces of the shell 40, the sleeve 44 and the-tubular electrode 45, as well as the mer cury itself. This vapor space 62 also provides for 30 free transmission of the heat generated at the outer end of the sleeve 44 due to rnaking and be joined before firing if desired. breaking of contact thereover between the bodies The electrode I5_it will be observed adapted , of mercury 53 and 54, to ali parts of the switch 35 to engage the mercury both on its axially facing envelope, whereby no loeaiized points of heat or end surface and on its radially facing or side generation are allowed to build up. surface. This radial bearingJr or contact reduces In the operation of the switch shown in Figures the contact resistance between the electrcde..and ‘ 2 and 3, when the switch _is in the position shown the mercury with minimum amount of mercury in Figure the circuit is broken between the in the recess 22 while preserving the desired re bodies of mercury 53 and 54, which are in respec 40 tive engagement with the electrodes 45 and 40. Considering now Figures 2 to 4, inclusive, the ' Upon tilting of the switch in a counterclockwise peat performance. . switch shown-in this embodiment of the invention comprises a drawn metallic shell 40 of iron, stain ’ less steel or suitaole iron alloy, having the flared directionabout its longitudinal axis, as shown in' Figure 3, the twofbodies of mercury 53 and ,54 both move forwardly with respect to the end of 45 end 42 adapted to receive a ceramic insert 43 of v the sleeve 44, »and come into engagement about porcelain or the like, the insert 43 having a for wardly extending substantially cylindrical sleeve portion44, which sleeve portion is adapted to re 50 ceive a tubular sleeve electrode 45 which may beof drawn sheet metal ofthe same material'as the shell 40 and which electrode is carried by the headed end of a shank 46 extending outwardly through the rear end of the insert 43. The sleeve lss 45 and the shank 46 are secured in fixed position with respect to the insert 43 by means of the washer 41 and nut 4e threading over the extend ` ing end of the stud ë‘ô, there being a suitable lre silient conical rubber bushing or gasket 49 inter 60 posed about the stud and compressed ,and ex pan-ded within the defining wedge-shaped open ing in the insert through which the stud extends by endwise pressure of washer 41. A suitable electrical conductor 50 is soldered or otherwise 65 secured tc the outwardly extending end of the. stud 46. The sleeve 45 may be made of iron or stainless steel or the'like with a copper stud,46 70 the defining edge of this’ sleeve, thereby closing lcontact between the electrodes 45 and 4l). It will be noted that the point at which contact is rnade and broken `is about the defining edge c-f the ceramic sleeve 44, spaced away from the ceramic 43 and from t-he inner> surface of the shell 40. This provides for generation of heat at a point removed from the electrode seal 49, and from the ' ceramic seal 55. , In addition, it removes the point of generation of heat away from any of the metal surfaces of the electrode 45 or electrode 40, and consequently provides for free action of the liquid fill 60 dis- ' »sipating this heat to all parts of the -switch enve 60 lope, and preventing building up of localized heated spots. Also, due to the definite relation of ‘the sleeve 44 withv respect to the shell 40, a positive opening and closing of contact at the same points of inclination is assured, thus giving 65 “repeat” performance, that is, the opening and ' closing oi the switch at the same angular posi brazed to the end ivall thereof, as shown as a tions -for successive operations of the switch. modification in Flgure ,11. Referring now to Figure 5, we provide a ceramic sleeve 44", which may correspond to the ceramic " , I It will be noted that Ithe cuter end of the tubu lar sleeve electrode 45, indicated at 52, is dis sleeve 44 of Figures 2 to 4, inclusive, but which is posed inwardly of the end of the ceramic s‘ieeve _44, and that a body of vmercury 53 forming part tending end of the sleeve 44', which‘is provided ' 'of the mercury fill is carried within this sleeve in 75 engagement with the inner surface of the sleeve not as great in longitudinal extent. To the ex with the, annular shoulder 65, we secure a modi fledtype of breaking edge, which is shown as a 75 5 2,132,920 'substantially cylindrical sleeve 86 having an in wardly extending tapered portion 61 at the outer end thereof, the sleeve 86 being provided with ex tending cylindrical iia'nge portion 68 extending about the shoulder 65, the sleeve-66 being secured ing provided with an outwardly flaring recess 95 receiving the compressible sealing gasket 96 for sealing the shank of they electrode with respect to the insert.' As here shown, the washer 93 rests against the end of gasket 95 only. A predetermined body of mercury 91 is dis posed on the iioor of the switch envelope, and edge formed by the tapered surface 61 is con siderably wider in extent, that is, is radially `it will be noted that the lower surface of the . f tothe sleeve` 44' by cementing.~ The breaking thickened toprovide for slow motion operation 10 of the switch, whereby the .two bodies of mercury 53 and 54 will not come together with as great a rapidity as provided merely by the sleeve 44. Optionally this edge may be cut back, as shown in Figure '1, to increase the acuteness of the breaking angle. ' electrode head 89 is positioned substantially at the lower edge of the head approximately .015” io lower‘than 'the meniscus height of the mercury 91, 4whereby the mercury' will make contact be- ' tween the shell 80 and the electrode 89 Without ñrst engaging the ceramic 84. The floor of the envelope is thus maintained level and no'uphill 16 rolling of the mercury is necessary. The in - In Figure 6 we show a still further modified -form of breaking edge, comprising a sleeve' mem- _ eluded angle of operation of such a switch can ber 10, having a suitable recess Íportion 12 for receiving the end of the stub porcelain sleeve 20 44', and having a double rounded outwardly ex tending defining edge 13, which provides a spill _ over or snap operation of vthe switch; due to the fact that the two bodies of mercury snap over the rounded portion of thè-edge 13 and come into engagement in a direction substantially normal to their original direction of movement. This provides for engagement ofthe mercury at an y be maintained within 1/¿°. The interior of the envelope is provided with a partial fillingA of tri ethanolamine, or a similar liquid having equiv 20 alentproperties, as indicated at 98, in the man ner _described in connection Awith previous em bodiments of the invention. - Figures 9 and 10 are directed to a switch of the ceramic shell type, and disclose switches of the same general construction as indicated by corresponding reference numerals. Thus we pro vide a ceramic cup-shaped shell |00 having an accelerated speed of engagement, which pro duces a sufficient impact to completely close annular _externally thickened portion |02 adja 'so 30 the circuit without any frying or sputtering be ~cent its open end.A The closed end of the shell |00 is adapted to receive an electrode button |03 tween the advancing edges of mercury as the having a shank portion |04 extending through switch should be> slowly tilted. It isl to be ob the shell and sealed with respect to the shell served that. in the forms shown in Figures 2 to by the tapered gasket |05 which is axially com 7, both bodies of mercury have movementtoward l pressed'into sealing position by the nut |06 en 35 35 and away from eachother, with the resultant gaging the outer end of the shank |04. double speed of engagement and separation. At its opposite end, the shell |00 receives the In the embodiment of the invention shown in closure cap |01 having the annular clamping por Figure 7, we provide a still further modified type tion |08 provided with a spun-over edge |09 en . . of breaking edge comprising the sleeve 15 having 40 the cutaway annular ring portion -16 for cement ing the same to the end of the stub shaft 44', and provided with an externally chamfered acute angle breaking edge 11, cut back from the inner defining periphery of the sleeve 15. This edgev 45 forms a definite and positive point of separat ing the mercury, whether moved rapidly or rela .tively slowly, and thereby permits repeat per formance, i. e., the feature of making and break ing contact at the same angle'at all times. This 50 feature we believe to be unique in this sleeve type of switch. The present switch requires to - be held in no particular angular position about its axis, since it is symmetrical with respect to its longitudinal axis. 55 ' In Figure 8 we have provided a switch requiring gaging the frusto-conical washer ||0 for com pressing the resilient gasket ||2 into tight seal ing engagement with the external tapered sur faces of the portion |02 of the shell. Welded, or otherwise suitably secured to the inner surface of the cap member |01, is a tubular sleeve mem l45 ber I I3 having a relatively snug fit in the interior of the shell |00 and being closed at its opposite end across the inner face'of the cap member |01. A suitable filler opening is formed in the mem bers |01 and II3, and is closed by the iiller plug 50 H4. ' - Referring 'now speciñcally to Figure 9, a body of mercury ||5 is disposed within the envelope comprising shell'l00 and sleeve H3, and upon tilting of the envelope the mercury is adapted to 55 move toward and away from the electrode button only a small operating angle. In this construc |03, which is preferably formed of stainless steel’ tion the metal shell 80 is provided with the usual ' or other metal not wet by the mercury. This filler opening 82 and sealing plug 83. At its open produces contact'- between the sleeve ||3 _and end the shell 80 receives the ceramic insert 84 button |03, and controls the circuit through the 60 60 cushioned in sealed engagement within the shell two flexible leads ILS and ||1 electrically con by means of the annular tapered compressible gasket 85 and the frusto-conical ring 86 which nected- to the button and the sleeve. Suitable is pressed longitudinally against the gasket by the liquid iill is introduced into the envelope, as in dicated at ||8, to take care of heat dissipation spun-over edge 81 of the shell 8|).` 65 and the like. Extending centrally through the insert 84 Nis 65 In Figure 10 we have modiñed the construction a second electrode stud 88, having an inner hemi ` spherical head portion 89, preferably formed of ` to produce va switch having a larger operating a non-wetting metal, such as stainless steel, pro jecting outwardly of a central boss 90 formed'on 70 the insert. The surface of the insert adjacent the boss 90 is annularly recessed, as at 92, to posi tion the head 89 of the second-electrode inwardly -\ of adjacent portions of the insert. 'I'he stud 88 is secured in position by a washer 83 and nut 75 94 engaging the outer end thereof, the insert be angle and having mercury-to-mercury making and breaking contact. The button |03 ‘of this vembodiment is provided with a` substantially 70 hemispherical cup member -|20 held in the closed end ofthe shell |00 by the electrode |03. An an nular insulating ring |22, having an'internal frusto-conical spillway surface |23, is inserted into position with the small end of> the spillway 75 6 . 2,132,920 adjacent the> cup |20, whereby a small body of? larged open end, a ceramic insert in the open mercury |24 is trapped on the inner surfaceoi’ end of said shell, ,resilient sealing means com the cup behind the vertical edge |25 of the ring .pressed radially between said insert and the in |22. 'I'he ring |22 is cemented or otherwise terior of said enlarged opened end, a ceramic suitably secured in position. The sleeve ||3 and cap member |01 are as. sleeve extending longitudinally inwardly from said insert and of a diameter substantially less sembled' `in position in the manner- previously than the internal diameter of said shell, a tubu described, and the body of mercury .||5 is intro lar electrode Áwithin said sleeve and abutting duced into the switch envelope. In the operation .against the insert at the insert end of said sleeve. 10 of the switch to close the circuit, the 'mercury an extension of- the electrode supportingV said 10 ||5 moves to the left, up the surface |23, and electrode in position and extending outwardly then, due to its accelerated movement up the .centrally of said insert, compression seals of converging surface, rushes into contact with the> yielding material for sealing the ceramic radially. mercury |24, closing'the circuit through the within the open end of said shell and sealing said electrode with respect to said shell, a body of 15 vmercury moves down the diverging surface with mercury'in said shell and adapted to make and increased momentum, until finally the gravita break contact between said electrode and shell tional pull'overcomes the cohesion between the over the extending edge of said sleeve member, bodies |24` and ||5, and themercury is parted and an anhydrous alkaline liquid fill in said. 20 over the sharp edge between surfaces |23 and -shell for dissipating heat from said edge to all |25, whereby the surface tension snaps the ?ad parts of said shell.` ' jacent contiguous edges into receded position. '2. A switch of the metallic envelope type com Thus a substantially snap action type of switch ` prising a >tubular cup-shaped metallic shell hav is produced. ing an enlarged open end, a ceramic insert clos „ It will be noted that in both Figures 9 and 10 ing the open end of said shell, an annular rub the actual making and breaking of `the circuit ber gasket compressed between -the external an 25 occurs at a point removed from the gaskets ||2, nular surface of said insert and the exterior whereby the'gaskets are disposed at the relatively surface of the open end of said shell, an integral switch. Upon opposite tilting of lthe switch, the ` ' cylindrical sleeve extending longitudinally from 'It is of paramount importance that the rela - said insert into said shell, an annular electrode tion of the volumeY of liquid ñll to the `volume of surface engaging the interior of said sleeve inter the vapor? chamber> be accurately controlled in mediate the ends thereof, a stud securing said order that proper limitation of pressure during in said sleeve and extending outwardly heating be obtained. The liquidñlm provides electrode through said insert, a rubber gasket about said 35 for cleansing of the internal surfaces of the lstud and compressed against said insert, an switch envelope and keeping them clean. .The integral flange'on said insert surrounding said 35 vapor produced by boiling, and its condensation, stud and extending axially outwardly beyond the provides for rapid dissipation of heat from a end of said shell, and a body o_f mercury vfor ~localized point of heat generation in order that bridging said shell and electrode about the inner overheating of any particularportion of the end of said sleeve upon tilting of said switch. so cool portion of the switch. switch will be prevented. It is apparent,- how ever, that this ratio or relationshipbetween thesetwo factors may be varied, depending upon the _type of switch which is employed, the currentV which it is required to control, vand other similar factors which must be considered. Therefore, while we have disclosed a particular ratio of ap proximately 3% of liquid 'fill inI the vapor space, we do not intend to limit the invention to ex actly this particular percentage, since it is ob vious that the >proportions can be regulated or 3. A switch of the metallic envelope type com 40 prising a tubular cup-shaped metallic shell hav ing an enlarged open end, a ceramic insert clos ing thevopen end of said shell, a rubber gasket compressed between the external annular sur 45 face of said insert and the inner surface of the , open end of said shell, an integral sleeve extend ing longitudinally from said insert into said shell, an electrode within said sleeve Iextending to a point adjacent the open end thereof, a stud 50 varied as desired to meet certain specified con- . securing said electrode in said sleeve and ex ditions. tending outwardly through said insert, a rubber - One primary concept vinvolved in this phase of the present disclosure is to reduce _the amount of liquid fill to the point that when the entire liquid ñll is vaporized the pressure of the vapor will then not exceed the strength of the shell or con tainer of the switch. 'I'his medium, i. e., a con densing vapor, is a highly eiiicient means for transferring heat. .'I'he parts are so proportioned that on rated maximum duty the liquid will not all be vaporized, but> suiiicient vaporization oc curs to carry off the necessary amount of lieat to keep the temperature Within safe limits. If rated maximum is exceededy the pressure may rise, but never to the point of breaking orde y stroying the container. , - i gasket about said stud and compressed -radially against said insert, insulating ñange means on said insert surrounding said stud axially out 55 wardly of the-end of said shell, a body of mer cury for bridging said shell and electrode, and means for making and breaking contact between said shell and electrode over the open end «of said‘sleeve. y _. >fi. A mercury switch of lthe closed metallic en velope type> comprising a liquid fill consisting of an anhydrous alkaline liquid of low vapor pres sure and having a substantially constant vis 85 cosity within the temperature range‘to which it is subject and being inert with respect to'the ' mercury in-said switch, said liquid rlll compris We donot intend to be limited to the speciñc" ing` approximately 3% of the volume of the details shown and-described, nor to the propor switch envelope. ' ` tions or sizes shown, as mòdiñcations of our in ventiony will be obvious to'thosef skilled in the art. We claim: . 1. In combination, in a switch of the class de scribed, a cup-shaped metal shell having an en 70 5. In a mercury switch having a switch en velope, _an anhydro alkaline liquid ñll therein above the mercury i said envelope, the volume of said ñll being such that complete vaporizatio / thereof will not produce a pressure/sumcieí to 75 2,132,920 rupture said envelope and associated parts of said switch. . » 6. In a mercury switch, a metallic cup-shaped shell, a ceramic insert in the open end thereof, lcompressible’gasket means between said shell vand insert, an electrode carried on the inner surface of said insert and having an outwardly extending shank, gasket means about said shank and compressible against said insert, a- body of mercury in said shell of such quantity that the meniscus height thereof is substantially equal to the radial distance between the inher surface of said shell and the peripheral surface of saidl elec trode, and a vaporizingpartial liquid iill in said 15 shell for dissipating heat therein during rapid operation of said switch, said gasket means be of substantially not more than a ñlm in contact with the mercury at the point of greatest heat generation, said film being locally vaporized andl the vapor carrying the heat to the envelope to equalize the same. l 11.'In a heavy duty mercury switch of the metal-envelope type comprising a metal shell and an insulated electrode sealed together and insulated from each other, a body of substantially pure mercury for making and breaking connec 10 tion between the shell and the electrode, said shell being beaded over the insulation of the electrode to provide a closed envelope capable of withstanding high internal pressures and tem peratures substantially in excess of boiling water, 15 and a small quantity of anhydrous _triethanol ing so shaped as- to relieve excessive internal amine forming a iilm of liquid in contact‘with pressures in said shell but preventing entrance the mercury and being vaporized locally by the heat of the current to transfer heat from the ' A r ` point of vaporization to cooler parts of the en 20 ’7. A heavy duty switch comprising a metal 20 ' shell, an insulator, and an electrode deñning an, velope, where it is condensed. 12. 'Ina mercury switch, a metallic cup-shaped envelope which consists chieñy in 'a metal heat conducting wall and which is of great strength shell, an insert closingone end of said shell, a to resist internal pressure, a body of substantially body of mercury in said shell, an electrode car ried at the inner end- of_said insert and radially 25 pure mercury adapted to make and to break con tact between the metal shell and the electrode, spaced from said shell a distance substantiallyv and a thin film of a viscous anhydrous alkaline equal to the meniscus height of said mercury, liquid of high boiling point which is in contact said insert having an annular recess in the radial with the mercury and which is vaporized at the inner face thereof about said electrode of a curva of heat generationv and condensed upon ture corresponding to the curvature of the ap 30 so. point the metal walls of the envelope to dissipate heat proaching edge of said mercury, and a shank and equalize the temperature of the parts of on said electrode extending outwardly through v the switch, the amount of liquid in saidenvelope said insert. . -13. In a mercury switch, a ceramic cup-shaped' being so ‘low-that excessive pressure is avoided by vaporization of the liquid as fast as it flows envelope having an open end and having an en larged annular wall portion about said end, an to the point of heat generation. » 8. In a mercury switch of the sealed envelope electrode sealed in the opposite end of said en velope, a second tubular sleeve electrodev ex type having iron electrodes and a body of sub tending into the open end of said envelope and stantially pure mercury for making andV4 break ing circuit betweenl the electrodes, a limited fill _terminating within said envelope iat a point of triethanolamine providing not substantially spaced from said electrode, a retaining flange of air thereinto. more than a thin film which is adapted to be > vaporized locally by the action of makingl or breaking the circuit, the vapor thereof engaging the walls and there being condensed. 9. In a mercury switch, a tubular ferrous en for said second electrode embracing the enlarged wall portion of said envelope, and resilient seal ing means compressed between said flange and said enlarged wall portion. 1 . 45. 14. In combination, a pair of cup-shaped mem velope, a plug of insulation closing said envelope, bers disposed in telescoping relation- with the the end of said envelope >beingl beaded over a open ends thereof in overlapped relation to form@v portion of the plug -«'“to retain said plug- -against aA switch envelope, annular sealing means sur-i internal pressure, a central electrode extending rounding an end-of one of said members', means 50 50 -through and sealed to said plug and _having a carried by the other member for radially com head upon the inside thereof preventing the ex pressing said sealing means into sealing engage pulsion of the electrode by internal pressure, a ment to form a sealed switch chamber, a body of mercury in said chamber,- one of said mem body of substantially pure mercury in the en for connecting and disconnecting the shell bers being> metallic and the other being formed of 55 sa A velope and electrode, and a small quantity only of refractory insulating material, and an electrode ethanolamine in said envelope and in contact carried within said chamber by said insulating member and spaced from the other member; said with the mercury, said ethanolamine being pres ent -in less than 5% of the free internal volume mercury bridging between said electrode and said other member upon tilting of the switch chamber. 60 of the envelope and being capable of being va 15. In combination, a cup-shaped ceramic porized locally by operation of said switch under member, a cup-shaped metallic member fitting load in making and breaking the- circuit. into and- extending toward the closed end of 10. In a mercury switch, a tubular ferrous en ' velope, a plug of insulation closing said envelope, said ceramic member, electrode means carried within the closed end of said ceramic member, 65 65 the end of said envelope being beaded over a por an insulating ring within said ceramic member tion of the plug to retain said plug against in ternal pressure, a central electrode extending between >¢said electrode means and the inner end 1 through and sealed to said plug and having a vof said metallic member forming ~an inclined raceway therebetween, and ñuid conducting head upon »the inside thereof preventing the ex pulsion'of the electrode by internal pressure, a means for eiîecting connection between said 70 body of substantially pure mercury in the en-_ metallic Amember and said electrode means over velope for connecting and disconnecting the shell said raceway upon tilting of said switch. 16.7In combination, an elongated cup-shaped and electrode, and a small quantity of an anhy -drous alkaline liquid of a boiling point in excess ceramic member having an open end, a -tubular 75 of that of water, said liquid forming a thin layer electrode sleeve sealed in the open end ofwsaid/ /75/ 8 '2,132,920' member, electrode means carried within said type, a cup-shaped metal shell forming one elec ‘ member at the closed end thereof and spaced trode and having an enlarged open end, a re from the inner ende ef saidi electrode sleeve by an annular wall portion of Ysaid ceramic mem ber, and a body of mercury in contact with said electrode sleeve and movable into contact with fractory insert in said open end having an axially . tapered- bore opening into the interior of said envelope, Yan annular resilient gasket interposed between the external annular surface of said in said electrode means upon tilting of said ceramic - sert and the adjacent internal surface of the en member. . ‘ . l e larged end of said` shell, said shell having its de i’ining edge forced radially inwardly to eifect ra dial and axial compression of said gasket, an electrode carried within said bore and having its periphery spacedzfrom the annular defining sur face of the smali end of-said bere, a body of Y -. 1f?. In a metallic envelope mercuryVV switch hav 10 ing two vbodies of mercury adapted to makeand break contact over an'insulating surface by rela tive movement therebetween, a film of an anhy drous alkaline liquid' over said bodies of mercury, said ñlm serving toi maintain maximum surface mercury retained in said bore in contact Ywith a . compressed therebetween upon relative movement portion of the face and periphery of said elec trode, and a second body of mercury in said shell adapted to makeY and break contact with said of Leaid mercury and to assist its; move is `tension ment. the films on said`bodies of‘mercury being toward each other to increase the head of mer ñrst body of mercury at a. point spaced from said _ cury at the-contacting surfaces, andethe potential across s_aid bodies of mercurypuncturing said electrode. ñlm to produce instantaneous enlarged surface contact between said bodies for reducing the re ing a substantially cup-shaped switch chamber 22. In a metallic envelope mercury switch hav 20 defined by metaliic walls and closed at one end by , sistance to passage of current through said con a refractpry ceramic insulator carrying a metallici electrode, said chamber having a liquid cgntactorY _ 18. In surfaces. a mercury switch, a cup-shaped metallic ' 25 tacting envelope having an lenlarged open end, a ceramic insert in said open end having an external an nular shoulder, resilient sealing means between -sald enlarged vend of Ysaid envelope and saidV movable upon tilting of said switch to make and .25 break contact between said envelope and said electrode, the method of maintaining the switch cool during operation at its rated capacity which comprises providing a limited flll of an anhydrous shoulder, said enlargedend having its defining alkaline liquid which clings to and-moves with 80 edge pressed radially inwardly axially outwardly _ said contacter, eand has .a boiling point below of said shoulder to lock _said insert in sealed'posi the temperature vto which flow -oi! normal rated ' tion therein, said ¿insert having a tubular'` sleeve current-¿tends to heat said conductor, vaporizingVV extendingaxiallyï’iinto Vsaid envelope in spaced ' said liquid fill at vthe point of said contact bei relation thereto, a tubular electrode within said tween .said envelope and said- electrode by the sleeve terminating adjacent the inner endthereof and having a shank portion vextending outwardly through said insert, anda body Y'of mercury in saidenvelope for bridging between said electrode and envelope and makingV and breaking contac ~ over the defining edge of ?said sleeve. ` ' 19. Means for dissipating heatv from the*A point of generation thereof in a sealed metallic en velope mercury switch having a ceramic insert heat generated in said contacter, providing un restricted movement of said vapor into contact with said metallic walis to dissipate said heat therefrom and to condense said vapor, and pro viding for freeë return of said condensate into contact with said contactor. v 23. A. switch comprising a first cup-shapedr _member having a central axially projecting tubuê lar portionv secured to the base thereofi and de 45 in one er?el thereof Vcarrying an electrode and hav y ing a body of mercury therein adapted to make flning therewith an annular groove, a second 45 and break contact betweengsaid envelope and electrode’Y over an internal surface of said‘insert, comprising an anhydrous alkaline -liquidi-lll of" 50 small volume compared to the internal volume of -said switch and adapted ¿to ‘adhere to the mer cury, said ñll having a?relatively high boiling in said groove, an electrode carried at the closed point whereby upon arcing at said surface saidl cup-shapedV member having its open ,end sealed end of ~said second member, and iiuid contact ing means for bridging between saidl electrode and said tubular portion upon tilting o1' said 50» switch. , i 24. _A ceramic insert for a mercury switch coni; prisinga cylindrical portion andan enlarged head , i fill vaporizes and'passes to cooler portions of said ë portion having a tapered external surface cori 55 `'Witch where it is condensed and flows by gravityS verging toward the cylindrical portion, said in 55 back to the point of heat generation. Í - _ sert having imperforate sidewalls and having 20. Means forfdissipating heat from the point a conical tapered runway terminating in a sharp of generation thereof in a sealed metallic envelope Y mercury switch having a ceramic (insert in one 60 end thereof carrying anî electrode `and having a body of mercury therein adapted to make and peripheral edge defined by a radially extending -groove terminating theÈ conical runway. ' 25. In combination in a mercury switch, a bushing of reîractorylfinsulation having imper break contact between said envelope and elecf forate side walls and having a peripheral shoul- Y ' trode over an internal surface ofsaid insert, com- ’ der deñning aY wall of a mercury retaining pocket prisingr an anhydrous alkaline liquid fill of smalilf volume âcompared to the internal volume of said* and a bore extending in one direction'from said 65 switch 'and adapted to. adhere to the mercury, shoulder and forming a runway for mercury, said ¿said fill: having a relatively high boiling point? bushing having a substantiaiiy cylindrical por-v -whereby upon `arcing at said ïsurface ?said ñll tion extending in the apposite direction from said vaporize’s and passes' to cooler portions of said .shoulder to form a part of said mercury retain 70 switch whereit is condensed and flows by gravity ing pocket, alrtubular metal shell having Ian en-> larged sealingportion having spaced inwardly back to the point of heat generation, said vapori zation producing an increased pressure in said extending shoulders for holding the bushing switch tending to minimize arcing during making l against endwise displacement in either direction and breaking of contact. ' è relative to the shell, and a resilient annular body ’ 75 21. In a mercury switch of the heavy duty of insulation disposed between the shell and saidv 2,132,920' bushing and being held in compression uponv the external peripheral wail of the bushing whereby ¿i the bushing is also placed under compression. 26. The combination of claim 25 with an elec¿5 trede carried by the bushing, said electrode hav- ' I f 9 bushing, a resilient deformable sealing b?hing surrounding said stem within said refractory bushing, and ineens for holding said sealing bush ing in compression to seal the electrode tothe re Iractory bushing. ‘ . i ing a disc-shaped portion closing~ of! said cylin- PAUL S. BEAR. drical portion and forming a wall of said pocket and having a stem portion extending outside said HERBERT E. BUCKLEN'. _ - v_ v CERTIFICATE 0E coRREcTIoN. Patentl No. 2,152,920. ' ' v -- . october 11, 1958. PAUL s. BEAR, ET AL. It is hereby certified that error appears in the printed. specifi-cation of the above numbered patent requiring correction‘as follows z Page 6 , second column, line 27 , claim 2, for the word "exterior" >read interior; and that ’ the said Letters Patent should be read with this correction thereinrthat the same may conform to.the record ofthe case in' the Patent Office. _ ‘Signed and. sealed' this 29th day of November, A. D. 1958; Henry Van Arsdal e (Seal) - I ` l A Acting` Commissioner of Í’dtents.