US1991350A - Electric connecter - Google Patents

Description

Feb. 12, 1935. C GREEN ELECTRIC CONNECTER Filed Feb. 28, 1921 "Fig.2.

n w@ o e r t0 mii v M 4 fl TmMWMS m m a y b .Patented Feb. 12, 1935 ELECTRIC CONNECTED Charles M. Green, Swampscott, Mata, assignor to General Electric Company, a corporation of New York Application February 28, 1921. Serial No. 448,520 as Claims. (01. 200-152) The present invention relates to electric current conveying parts for electric devices, and particularly to sealed-in conductors for devices containing a body of mercury as, for example,

mercury switches, mercury rectifiers, arc lamps,

and the like.

Certain oxidizable refractory metals, particu larly tungsten and molybdenum, have been found to be fully as satisfactory as platinum for sealing into glasses having substantially the same thermal coemcient of expansion as the sealed-in metal. A thin coating of the oxide which forms on the metal when the seal is made helps in the production of a permanently gas-tight seal, but the poor electrical conductivity of the oxide zone beyond the glass introduces a relatively high (contact) resistance between the leading-in-wire and a body of mercury. The oxides can be cleaned off of the metal previous to sealing of the 20 glass flare into the bulb, but, ordinarily, the heat required to seal in the flare and to properly anneal the glass, reoxidizes the metal, and it is extremely difiicult, if not impossible, to remove or reduce this oxide on the lead wire inside of the bulb. Oxide of tungsten may be reduced by hydrogen at a high temperature, but the reduction temperature is above that which the glass, even heat resisting glass, will stand.

In accordance with my invention, vI have provided a leading-in-conductor which overcomes this difliculty and which consists of a refractory metal, such, for example, as tungsten, tipped with a metal, such, for example, as nickel or iron, referred to in some of the appended claims as of the iron group, the oxide of which may be reduced by. hydrogen without affecting the glass, thereby cleaning the surface of the metal tip and even going so far as to have the tip wet by the mercury. By this means the best possible connections between tungsten leading-in-wire and mercury is obtained, and the interaction of the hydrogen, the mercury and the metal electrodes is such that the connecter is substantially nondeteriorating.

The accompanying drawing shows for illustrative purposes in Fig. 1, as a side elevation partly in section, a mercury switch or contactor containing a leading-in-conductor embodying my invention; and in Fig. 2 aleading-in-wire sealed into a glass flare.

This switch bulb comprises an envelope 1 consisting of sodium magnesium bore-silicate glass (also known to the glass trade as G 702 P, Corning (N. Y.), Glass Works), into which conductor 2 of tungsten, molybdenum or the like, referred to some of the appended claims as a metal of the tungsten group, may be sealed in accordance with Weintraub Patent 1,154,081 of September 21, 1915. G 702 P glass contains an appreciable amount of lead. The envelope contains two pockets 3 and 4. Into these pockets extend reentrant portions 5 and 6 of the envelope, into which are sealed the conductors 2 and 'I. The envelope or bulb 1, contains a body of mercury 8, completing the electrical circuit between the conductors 2 and 7, the quantity of this mercury being so proportioned that when the bulbis tilted the circuit" is broken by separation of the mercury body into two parts. To assist in this break ing of the mercury body, small indentations 9 and 10 may be formed in the wall of the bulb. After having been carefully evacuated the bulb is filled with dry hydrogen at substantially atmospheric pressure. The conductors 2, 7, may be assumed for the purpose of illustration to be of tungsten.

In accordance with my invention a globule 11 of an easily reducible metal, for example, nickel or iron, is applied prior to the sealing-in process to the end of the tungsten wire. The tip may be applied by drawing an arc in hydrogen between the tungsten wire and a nickel wire. .The nickel preferably is connected to the positive terminal and the tungsten to the negative terminal of an electrical circuit. The tungsten being held below the nickel, the two terminals are brought together, then separated, forming an are which melts the nickel and reduces the oxide of tungsten on the tungsten wire, thereby cleaning it, and the globule of nickel is dropped off the nickel wire down on to the tungsten, forming a bead on the end of the tungsten wire. The tungsten wire may then be sealed into a flare tube 12, as shown in Fig. 2. A globule of nickel, 13, preferably is deposited on the opposite end of the wire as well, to assist in the connection of the protruding end of the tungsten wire to an electric conductor 14, which may consist of copper, or other suitable metal. The copper lead is electrically welded tq 'the nickel globule 13 on a tungsten lead after the bulb has been exhausted. A small quantity of'suitable cement is applied where the tungsten wire comes up through the flare tube12 above the main bulb as shown at 15. This protects the glass from being injured by the heat of the arc whenthe copper lead iswelded on to the leading-in-yvire within to of the glass, and furthermore, gives additional support to the leads, strengthening same.

When the tungsten wire tipped with nickel has been sealed into the glass flare tube, the nickel is naturally more or less oxidized. The oxide may be removed by grinding, but when the flare is sealed into the bulb the temperature required for the sealing in and proper annealing of the glass is suflicient to oxidize both the nickel and the tungsten. The nickel is subjected to the reducing effect of hydrogen while the entire bulb is heated to a temperature at which a reduction of the nickel oxide will take place, say, about 500 C. This treatment is repeated a number of times with fresh fillings of hydrogen to replace the hydrogen which has combined with the oxygen of the nickel oxide, reducing same and forming water vapor. It furthermore effects the reduction of the nickel oxide at a temperature which may be employed without injuring the glass. The nickel should be free from oxide, and under these conditions the nickel may be wetted by the mercury, or will be cleaned so that there will be low resistance connection between the tungsten leading-in-wire and the mercury. Furthermore, it is necessary that there should be a fairly large contact surface between the leading-in-wire and the mercury due to the fact that mercury has a high specific resistance, 94 10* in comparison with nickel 10.7 10" and tungsten 7 l0 After the nickel oxide has been reduced the bulb is evacuated, filled with pure mercury under vacuum, impurities being not over one part in a million. The bulb then is filled with dry hydrogen at atmospheric pressure, and is sealed off in. the usual manner.

The cement is then placed around the tungsten leads as they leave the glass bulb, allowed to harden, then the flexible lead 14 is are welded to the nickel tipped tungsten leading-in-wirc.

Mercury switches embodying my invention have a lower resistance, lower losses, and are more reliable than mercury switches containing a simple leading-in-wire of tungsten, or similar oxidizable refractory metal.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

1. An electric device comprising a glass bulb, a body of mercury contained therein and a leading-in conductor sealed into said bulb and contacting with said body of mercury, said conductor comprising an oxidizable refractory metal having joined thereto a tip of metal the oxide of which is reducible at a lower temperature than the temperature at which said bulb will be injured, said tip being freed from oxide by reduction after the conductor is sealed into the bulb.

2. An electric device comprising a bulb, a body of mercury contained therein, and a leading-in conductor consisting of tungsten sealed therein and extending into said bulb, and a metal coating the projecting portion of said conductor, said metal being reducible, after sealing-in said conductor, and at a temperature sufficiently low to avoid injury to said container.

3. In a mercury switch comprising a glass envelope, a body of mercury contained therein and a tungsten lead sealed into said envelope and projectingbeyond the seal, the projecting part being of such length as to be subject to oxidation during the sealing and annealing of the glass, the combination of a coating of nickel on said projecting part, said coating being free from oxide by reduction and making a good electrical contact with said mercury.

4. In a mercury tube switch, in combination, an

envelope of boro-sllicate glass carrying an appreciable quantity of lead and contacts sealed into the walls of said envelope, said envelope being filled with a gas having the property of assisting in removing heat from the high temperature points in the envelope.

5. In a mercury tube switch, in combination, an envelope of bore-silicate glass carrying an appreciable amount of lead and contacts sealed into the walls of said envelope, said envelope being filled with hydrogen.

6. In a mercury tube switch, in combination, an envelope of glass having a coefficient of thermal expansion substantially that of bore-silicate glass and greater than that of fused silica, contacts sealed into the walls of said envelope, and a con tact making and breaking member in said envelope for bridging the gap between said contacts.

'7. In a mercury tube switch, in combination, an envelope of glass having a coeflicient of thermal expansion substantially that of Doro-silicate glass and greater than that of fused silica, contacts sealed into the walls of said envelope, and a gas assisting in removing heat from said envelope.

8. In a mercury switch, in combination, an envelope of glass having the property of withstanding high temperatures and rapid fluctuations in temperature and a well formed thereon of borosilicate glass, mercury in said switch, and lead wires passing through the wall of the envelope and in contact with said mercury.

9. In a mercury switch, in combination, an envelope of glass having the property of withstanding high temperatures and rapid fluctuations in temperature and wells formed thereon of borosilicate glass, mercury in said switch, and lead wires passing through the wall of the envelope and in contact with said mercury.

10. In a. mercury switch, in combination, an envelope of glass containing an appreciable quantity of metal and having the property of withstanding high temperatures and rapid fluctuations in temperature, mercury pools in said envelope in the open position of said switch, and lead wires passing through the wall of the envelope and in contact with said pools.

11. In a mercury switch, in combination, an envelope of glass containing an appreciable quantity of metal and having the property of withstanding high temperatures and rapid fluctuations in temperature, mercury pools in said envelope in the open position of said switch, and lead wires of tungsten like material passing through the wall of the envelope and in contact with said pools.

12. In a mercury switch, in combination, an envelope of boro-silicate glass carrying an appreciable quantity of metal, wells opening into said envelope, and contacts sealed into the walls of said envelope and terminating in said wells.

13. In a mercury switch, in combination, an envelope of boro-silicate glass carrying an appreciable quantity of metal, a well opening into said envelope, and dividing the mercury into two pools in the open position of the switch, and contacts passing through the wall of the switch and terminating in said pools.

14. In a mercury switch, in combination, an envelope of boro-silicate glass carrying an appre ciable quantity of metal, mercury pools in said switch, and tungsten lead in wires sealed in the wall of the envelope and in contact with said mercury pools.

15. In a mercury switch, in combination, an envelope oi boro-silicate glass carrying an appreciable quantity of metal, mercury pools in said envelope in the open position of said switch, and a. gas in said envelope having the property of assisting in the removal of heat from the high temperature points in the envelope.

16. In a mercury switch, in combination, an envelope of boro-silicate glass carrying an appreciable quantity of metal, mercury pools in said envelope in the open position of said switch, tungsten lead in wires sealed in the wall of the envelope and in contact with said mercury pools, and a gas in said envelope having the property of assisting in the removal of heat from the high temperature points in the envelope.

17. In a mercury switch, in combination an envelope of boro-silicate glass, contacts sealed through the walls thereof, and mercury therein.

18. In a mercury switch, in combination, an envelope of boro-silicate glass having wells opening thereinto, contacts sealed through the wall of said envelope and terminating in said wells, and a body of mercury in said envelope.

19. In a mercury switch, in combination, an envelope of glass having the property of withstanding high temperatures and rapid fluctuations in temperature, mercury pools in said envelope in the open circuit position of said switch and lead wires in contact with said pools passing through the wall of the envelope in sealed relation to borosilicate glass carried by said wall.

20. In a mercury switch, in combination, an envelope of glass having the property of withstanding high temperatures and rapid fluctuation in temperature, mercury in said envelope, and lead wires passing through the wall of the envelope in sealed relation to boro-silicate glass carried by said envelope and being in contact with said mercury in a closed circuit position of the switch.

21. In an electrical contactor device for electric power circuits, a sealed container, electrodes positioned within said container, an atmosphere comprising hydrogen gas filling said container, and a body .of mercury movable to make and break the circuit between said electrodes, the latter being composed of a metal of the iron group, said device being substantially non-deteriorating by reason of the inter-action of the mercury, said atmosphere and said metal electrodes.

22. An electrical contactor comprising an elongated hermetically sealed container of insulating material, a quantity of mercury in said container adapted to ride back and forth on the inner surface of the container and lengthwise thereof when the container is tilted in opposite directions past a horizontal position, electrical conductors composed of metal of the iron group within the container in position to cooperate with the mercury to open and close the electric circuit through said contactor upon the tilting of the latter, and an atmosphere of hydrogen in the container, the action of the said atmosphere, the mercury and said electrical conductors being such that the contactor is substantially non-deteriorating.

23. An electrical contactor comprising an elon gated hermetically sealed container, a quantity of mercury in said container adapted to ride back and forth on the inner surface of the container and lengthwise thereof when the container is tiltedin opposite directions past a horizontal position, leading-in wires extending through the wall of said container and being of a material to provide substantially permanent hermetic seals therein, electrical conductors comprising a metal of the iron group at the inner ends of said leadingin wires and being positioned to cooperate with the mercury to open and close the electric circuit through the contactor upon tilting it, and an atmosphere comprising hydrogen filling the said container.

24. An electrical contactor comprising 9. hermetically sealed container, electrical conductors hermetically sealed in said container and severally terminating into an exposed portion within the container that is composed of a metal of the iron group, said exposed portions cooperating with the mercury to open and close the electric circuit through said contactor when tilted, an atmosphere comprising hydrogen gas filling said container, a quantity of mercury contained within said container and which contacts with said electrical conductors to open and close the electric circuit through said contactor, the action of said atmosphere, the mercury and said electrical conductors being such that the contactor is substantially non-deteriorating.

25. A mercury power switch comprising an envelope of glass, mercury therein, and electrodes, each of which comprises a lead-in sealed into said envelope and a terminal portion of metal of the iron group welded to said lead-in and extending into said mercury.

26. A mercury switch comprising an envelope of glass, mercury therein, and electrodes, one of which comprises a lead-in of a metal of the tungsten group sealed into said envelope and a terminal portion of metal of the iron group welded to said lead-in and extending into said mercury.

27. A mercury switch comprising an envelope of glass, a mercury therein, and electrodes, one of which comprises a lead-in of a metal of the tungsten group sealed into said envelope above the level of the mercury and a terminal portion of metal of the iron group welded to said lead-in and extending into said mercury.

28. A mercury switch comprising a longitudinal envelope of glass having mercury therein, an electrode sealed through the envelope wall and extending into said mercury, an electrode lead-in of tungsten sealed through the envelope wall at one end thereof and a terminal portion of nickel welded to said lead-in and extending into said mercury.

29. A mercury switch comprising a longitudinal envelope of glass having a well formed therein, mercury in said envelope, an electrode sealed through the wall of said envelope and extending into said mercury, an electrode lead-in of tungsten sealed through said wall above normal mercury levels and a terminal portion of nickel welded to said lead-in and extending into said well.

30. A mercury power switch comprising a sealed envelope of glass, mercury therein, and electrodes, each of which comprises a lead-in sealed into said envelope and a terminal portion of metal of the iron group welded to said lead-in and extending into said mercury, and a filling of hydrogen in said envelope.

31. A mercury switch comprising a sealed envelope of glass, mercury therein, and electrodes one of which comprises a lead of tungsten sealed into the envelope and a terminal thereon of oxygen free nickel.

32. The method of making an electrode for a mercury device into which it is sealed which comprises welding a nickel terminal portion to a tungsten lead-in portion.

33. In an electrical contactor device for electric power circuits, a sealed container, electrodes positioned within said container, an atmosphere comprising hydrogen gas filling said container,

and a body of mercury movable to make and break the circuit extending between said electrodes, the latter having mercury engaging portions or metal wetted by mercury, said device being substantially non-deteriorating by reason of the inter-action of the mercury, said atmosphere and said metal electrodes.

34. An electrical contactor for making and breaking an electric circuit, including a movable hermetically sealed hydrogen-filled container having a closed position and an open position, a quantity of mercury therein, leading-in conductors extending through the wall of said container and hermetically sealed therein, electrical conductors of a metal 01 a group consisting of nickel and iron at the inner ends of said leadingin conductors and positioned so as to be in contact with the mercury and complete a circuit from one leading-in conductor to the other through said mercury when the container is in the closed position, said circuit being broken when the container is in the open position, the surface of said electrical conductors being wetted with mercury whereby a relatively low resistance contact is made with the mercury in the container.

35. A mercury switch including a hydrogenfilled glass envelope, a body of mercury within said envelope. a pair of leading-in conductorl sealed in said envelope and provided with terminal portions of a metal 0! a group consisting of nickel and iron for engaging said body of mercury, said terminal portions being wetted with mercury.

CHARLES M. GREEN.

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