US1773036A - Mercury relay - Google Patents

Description

A"8-. 1930, A. s. FITZ GERALD 1,773,036

MERCURY RELAY Filed Jan. 12, 1928 2 Sheets-Sheet l Iwventov; Adan S. Fitz Gercdd; by Wad/wa His Attovneq Aug. 12, 1930. A. s. FITZ GERALD 1,773,036

' MERCURY RELAY Filed Jan. 12, 1928 2 sheets-sh et 2 Q/JZ 5 I 37 I 40 o W M 5 2% 5 Z 2/ J 3? 9 Li;

- Inventor:

Alorn S. Fitz Gerald,

His Attorney.

' such switches arenot suitable for'controllmg Patented Aug. 12, 1930 UNITED mm PATENT OFFICE ALAN S. FITZGERALD, OF SCHENECTADY, NEW YORK, ASSIGNOB TO GENERAL ELEC- i TRIO COMPANY, A CORPORATION 01' NEW YORK lanolin! RELAY Application filed January 12, 1928 Serial No. 248,317.

My invention relates to circuit controller to liquid contact controllers, such as sealed mercury contact switches, are well known in the art.. By the use of these controllers in,

circuits which must be opened or closed frequently, the burning of contacts and consequent maintenance which is an incident to the use of metallic contacts may be avoided, and the life of the controller increased.

In the mercury contact switch heretofore though any other suitable materialv which in general use, the mercury and contacts have been enclosed within a sealed tube pivoted to permit a limited rocking motion. While this arrangement has been more or less satisfactory where the current carrying capacity of the switch was small, and the operating forces available to tilt the tube were ample,

large currents because of the difliculty of providing connections sufficiently flexible to avoid hindering the operations of the mercury tube while at the same time havin suitable current carrying capacity and su' cient strength to withstand ordinary handling.

It is an object of my invention to overcome the abovementioned difiiculties by substituting for the pivoted mercury tube, a stationary vessel and causing the mercury therein to be diplaced by electro-magnetic influence to close the contacts.

Another object of the invention is to pro vide a liquid contact electric switch of a relatively large current carrying capacity.

which may be operated with a comparati ly small amount '0 power. A

The preferred embodiments ofmy invention, as illustrated inthe accompanying drawi'n will now be described, and the features .w 'ch I' believe to be. new -.and-patentable will be pointed out in-the appended gram ofthe preferred embodiment of my in vention in a mercury contact switch. I Fig. 2

1 is a cross-sectional view of the electromagnet shown in Fig. 1', taken on the line 2-2. Fig.

3 shows a modification of my invention in which the electromagnet is replaced by a pen manent magnet. Fig.4 illustrates an applicationof the same principle with the interposition ofmecnanical means between the mercury chamber and the switch which is illustrated as a disconnecting switch of a well known type, though it is obvious that it might be applied to any other t pe of switch.

Referring now to Fig. 1 of t e drawing, I

have illustrated a mercury contact switch comprising a vessel 1,containing the main switch contacts 3 and 3. This vessel is preferably of glass and hermetically sealed, ali may be readily formed in the desired shape may be used. It is not necessary to the op-' eration of this device that the vessel be sealed,

although in practice, it is usuall desirable. The contacts 3 and 3" are also sea ed into the vessel in case a sealed vessel is used, and they must be insulated from the vessel if it is made of electrically conductive material.

This vessel comprises a main mercury cham' and 11, sealed into the vessel. This mercury chamber 4 is filled with mercury which rises in the tubes 6 and 7 to a level 12 substantially below the contacts 3 and 3*. Contacts 3 and '3 might be placed normally below the mercury level ifintended to be normally closed. Surrounding the mercury chamber 4'. in the position in which the electrodes 8 and 9 .are mounted is a C-shaped electromagnet-13 having'a winding 14 terminating in the loads 15 and 16'. That is, the portion of the mercury chamber containing the electrodes 8 and 9 is arranged in the air gap of the electrom agv net 13, which ispreferably made only long enough to receive the vessel so that a maxi mum flux ma be obtained for a given magneto-motive orce.

Current of low voltage but high amperage is supplied to the electrodes 8 and 9, through binding posts 10 and 11 mounted in the main mercury chamber e from the secondary wind The urimar 17 of a m .rner 1s energlzed winding 1% of the winding 19 O1 in series with e exciting electromagnet 1 By this means the current flowing between the electrodes 8 and 9 1S kept substantially phase with the flui: set up by the electromagnet l3. lhe primary of the transformer 18 and the winding 14 are enerized through the leads 20 and 21 from a suit able source of alternating current 22. In this circuit may be placed a suitable switch 28 i the electrodes 8 and 9 through the mercury as a conductor. This mercury which is carrying the greater part of the current is in the air gap of the electromagnet13 and is acted upon in the same manner as the armature conductors of an electric motor. This elec- 'tromagnctic force propels the mercury to the right, and the mercury rises in the contact chamber 5 to the level 24 and falls in'the tube to the left until the difference in hydrostatic head just balances the propulsive force acting on the mercury. 1

As the mercury rises in the chamber 5, the circuit is completed between the main contests 3 and 3 This circuit will be maintained closed as long as the switch 23 is closed to energize the transformer 18 and exciting vinding 14, but will be opened as soon as they are deenergized.

.In Fig. 3, I have represented a further modification of my invention where the magnet 13 is 21;. ordinary permanent magnet and the electrodes 8 and 9 are connectedto a direct current source through a reversing switch 39. This modification may be used where the change in level of the mercury is small. Fig. 4 illustrates an application of the same rinciple involved in the apparatusjust decribed to the operation of a disconnecting witch or to operate any other movable device. In this figure the disconnecting switch comprises a base 26 on which are mounted the split contact 27 and the split finger 28 in which is pivoted the disconnect blade 29.

The disconnect blade has a projecting arm 30 to which is pivoted the operating link 31. The operation of the switch is similar in prin ciple to that described in connection with Fi 1, with. the exception that the difference in head of the two columns of mercury in the which the operation of this 37 and 38 is im )ressed upon a piston 3a perating in a cylin er 33. The piston 34 is e nnected by means of a link 82 to the operating lin 31. In addition, a double pole double row switch 39 is provided in the circuit of the exciting winding for reversing the current therein. This reversing of current in the exciting winding 14: relative to that between the electrodes causes a reversal in the direc tion of displacement of the mercury, which, in turn, may be utilized to open and close the disconnecting switch 29. A switch 40 is provided in the supply leads 20 and 21 to control. the operation of the disconnecting switch. The switch 40 is shown as a manually open ated device, though obviously it may consist contacts of some relay or other control device. here desired the switch 40 may, be omitted and-the switch controlled entirely by the switch 39.

While I have shown and described only the preferred embodiments of my invention, it is not limited to the structure disclosed but ohviously includes other modifications such as the use of a single electromagnet with a shed ing coil such as is well known in the art as applied to the induction disc relay, in place of the electroma netic means illustrated; or in place of a sealed vessel, an open vessel of proper form might be used; or in place of the-glass, vessel with sealed electrodes a metallie vessel might be used with the contacts 3 and 3 properly insulated.

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

1. In combination, an electromagnet, a

transformer having a primary winding connected in series with said electromagnet, and a secondary winding; a vessel arranged in the air gap of said clectromagnet containing spaced contacts, an electrically conductive liquid, and electrodes connected to the sec; ondary winding of said transformer for supplying an electric current to said liquid; and asource of alternating current for energizing said electromagnet in series with said transformer whereby said liquid is displaced from its normal position to control a circuit be tween said-contacts.

I 2. In combination, an electromagnet, a transformer having a. primary winding connected'in series with said electromagnet, and a secondary winding, a vessel arranged in the air gap of said electromagnet, containing an electrically conductive liquid and electrodes connected to the secondary winding of said transformer for supplying an electric current to said liquid, and a source of alternating current for energizing said electromagnet in series with said transformer whereby said liquid is actuated.

In witness whereof, I have hereunto set my hand. this 11th day of January, 1927.

ALAN S. FITZGERALD.

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