US2577653A - Mercury switch - Google Patents

Description

@su 4p E953 A, s, DYSART 2,57%@53 MERCURY SWITCH Filed May 22, 1945 3 SheGS-Sheel. l

A. S. DYSART MERCURY SWITCH Dec. 4, 1951 3 Sheets-Sheet 2 Filed May 22, 1945 Filed May 22, 1945 FICELQ A. DYSART E MERCURY SWITCH 3 Sheecs-Shee't 5 FIGLIO INVENTOR ARTHUR S. DYSAFZT ATTOIQ NEY Patented Dec. 4, 1951 MERCURY SWITCH Arthur S. Dysart, Elizabeth, N. J., assigner of one-half to Mabel S. Dysart, Elizabeth, N. J.

Application May 22, 1945, Serial No. 595,155

8 Claims.

Ibis invention relates to mercury switches and particularly to switches of this type operated by variations in the pressure of a gas iilled chamber forming part of the switch to move a quantity of mercury between contact closing and opening positions.

More particularly the invention relates to mercury switches in which a small quantity of kmercury is forced through an orice or along a channel into a position to electrically connect two terminals, movement of the mercury being effected by heating a chamber, closed except for the oriiice, so that the air or gas within the chamber, being increased in volume by being heated, will force the mercury through the orifice into another chamber or 'portion of the switch to connect the terminals of ya main or load circuit.

Any gas that will not combine with mercury may be used.

A primary object of the invention is to provide a pressure or heat operated mercury switch that will be simple, compact, and that will not easily get out of order.

A feature that enables the above object to be accomplished is that'the parts employed in the switch are few in number and easily assembled in permanent relative positions within a sealed member.

With the above and other objects in view the invention includes the features of construction and operation set forth in the following speciiication and illustrated in the accompanying drawings.

In the accompanying drawings annexed hereto and forming a part or" this specification, I have shown the invention embodied in several ldiiierent types of liquid contactor switches, but it will be understood that the invention can be otherwise embodied and that the drawings are not to be construed as defining or limiting the scope vof the invention, the claims appended to this speciiication being relied upon for that purpose.

In the drawings:

Figures 1, 3, 4, 5, 7, 9 and l0 are central` longitudinal sectional views of mercury switches showing diiierent embodiments of the invention.

Fig. 2 is a transverse sectional view of one form of the invention taken on the plane of line 2 2 in Fig. 1.

Fig. 6 is a transverse sectional view of .another form of the invention taken on the plane of line E-IS in Fig.

Fig. 8 is a transverse sectional View of another form of the invention taken on the lplane of line 8 8 in Fig. '7.

Fig. 11 is a transverse sectional view taken on the plane of line Ii-ii in Fig. 10.

In the above-mentioned drawings there have been shown a .number of different embodiments of the invention which are now deemed :preferable ior different conditions and services, but

(Cl. 20D- 122) it is to be understood that changes and modiiications may be made within the scope of the appended claims without departing from the spirit of the invention.

Brieiiy, and in its preferred aspect, the invention may include the following principal parts: First, adjacent chambers communicating with each other by means of a connecting orice or channel; second, a quantity of mercury movable from one chamber partially or wholly into the other; third, terminals mounted on each of the casings of the chambers; and fourth, means to heat or otherwise change the pressure of the gas in one or both chambers.

Referring more in detail to the gures of the drawings, and rst to the embodiment of the invention shown in Figs. 1 and 2, it will be seen that two metal casings I0 and I2 t partially one within the other and are held in their relative positions by insulating material such as rubber Iii, etc. Surrounding a portion of the inner casing I0 and disposed within the inner end of the outer casing I 2 is a channelled member of porcelain, or other insulating material, forming a rm body member I5. At the lowermost part of the inner casing IIJ is a small aperture I8, the body member I6 being so formed adjacent this orifice I8 that a channel is formed from the interior of the inner casing Ii) to the end wall of the outer casing I2. Mercury 20 within the casing Ill may therefore flow through the orifice I8 and between the sloping sides of the body member It to electrically connect the end walls of the casings I0 and I2 by this liquid conductor 22. Terminals 22 and 24 on the casings IIJ and I2 are electrically connected. when the mercury 20 is forced partially from the casing II) and comes into contact with the casing I2.

To force the mercury 2G from the position shown in Fig. 1 into Contact with the casing I2, a heating resistance 2E is provided within casing I0. When this resistance Zi is connected to a source of current as by a switch 23 connecting lead lines of a supply circuit, the heat increases the pressure and volume of the gas within the chamber of casing iii and forces the mercury 23 partially or wholly from this chamber into Contact with the end wall of casing I2. This connects terminals 22 and 24 electrically and closes the main circuit between terminals 22 and 2li of any type. Any excess gas will follow the mercury through orifice I8 into space II without breaking the continuity of the electric circuit. With the switch 2B opened the pressure within casing Iii will be reduced by cooling of the gas therein and excess pressure of the gas in the other chamber ywill return the mercury 29 to the position shown in Fig. 1 which will then open the circuit between the terminals 22 and 24.

Terminal screw 25 containsan axial hole 23 communicating with radial hole 2'! near its inner end. Screw 25 is pushed into chamber 9 until radial hole 21 connects with chamber 9. A rubber tube (not shown) may be attached to the outer end of screw 25 and the switch chambers exhausted. The desired gas is then admitted into the switch through the same tube at the desired pressure, preferably higher than atmospheric pressure. Nut 3| is then set up tight, drawing the head of screw 25 against plug 33, closing the radial hole 21 and sealing the gas into the switch.

Fig. 3 illustrates a modification of the embodiment of the invention shown in Figs. 1 and 2. Inner and outer casings I and |2, the. body member I6 within the outer casing, the terminals 22 and 24, etc., may all be similar to their corresponding parts shown in Figs. l and 2. In-

stead of the pressure within the inner casing I I6 being increased by heating the gas therein, a bellows 36 is connected thereto as by a nipple 32. A hand lever 35 moved about a fixed pivot or axis compresses and expands the bellows 36 and thus increases and decreases the gas pressure within this casing I9 and forces the mercuryl 26 into contact with the outer casing |2 in the same manner as in Figs. 1 and 2. A transparent plug I1 provides a window through which the action of the switch may be seen.

Fig. 4 shows a still further method cf increasing the pressure within one or the other of the casings I6 or l2 t0 force the mercury 2|! to -make and break an electrical connection between the casings. Surrounding one, or if desired both, of the casings, as in Fig. 4 are jackets 34' and 36 of any suitable material. Each of these jackets is provided with openings for the entrance and exit of a fluid. The fluid in one of the jackets may be heated or cooled to a different temperature from that in the other s,

jacket, causing a difference in temperature between the casings I0 and l2. When a diiference in temperature exists between the spaces in casings I9 and l2 the mercury 26 `will be forced from one to the other of its positions in the same manner as in Figs. 1 and 3.

Figs. 5 and 6 show a mercury switch employed as a rheostat to successively by-pass portions of a resistance. Outer and inner shell members in the form of metal tubes ||4 and ||6 are provided suitably insulated from each other as shown. Enclosed within the outer shell ||6 and surrounding the lower part of the inner shell H4 is a porcelain or other body member of heat resisting insulating material H8. This member I8 connects by a suitable channel or orice with the space within the inner shell H4. Within the body member ||8 a channel |22 is provided with a plurality of depressions or pools, each pool being successively slightly higher and grouped circularly about the inner shell |I4. Also each pool is provided with a contact connected to a point along the turns of a resistance wire |24. By heating the gas within the inner shell as by a heating resistance |26, the increased preesure drives a quantity of mercury |28 from the inner shell into the channel |22. As the mercury reaches the successive pools, contact is made with different portions of the resistance coil |24 and successively short circuits additional amounts of this resistance. If desired, the connection to the heating coil |26 may include a variable resistance |36 enabling the amount of heat supplied to the heating coil to be controlled to regulate the time necessary to force the mercury from the inner shell successively into the portions of channel |22 and thus delay the successive short circuitng of the sections of the resistance |24. As shown in Figs. 5 and 6, a contacter in the form of a vertical metal rod |23 extends into each of the depressions in the channelled member |22, serving to connect this depression with a point on resistance |24. Insulating sleeve |33 and insulating disc |35 are added to prevent accidental contact of parts of opposite polarity.

In Figs. 7 and 8 is shown a mercury oprated switch generally similar to that shown in Figs. 5 and 6 in that a mercury pool is forced from an inner shell H into channels formed within a body member |32 of insulating material and into contact with an outer shell H6. In this form of the invention, however, the channels in member |32 extend radially t0 enable mercury |28 in any channel to contact the outer shell ||6. The space within the inner shell H4 may be heated by a resistance like resistance |26 contacting the wall of the inner shell, the opposite end of the resistance being connected to an insulated terminal |34 extending through an insulating closure for the inner shell I4. When tilted in any direction, as by the rolling or pitching of a ship, one or more channels in member |32 will be maintained filled with mercury and contact with the outer shell will not be broken. By forming a central depression in the insulating body member |32 a quantity of mercury may be provided within the inner shell and surrounding the opening from the inner shell to maintain this opening sealed without any liability of the mercury contacting the cuter shell n until a material amount of mercury has been forced from the inner shell.

Fig. 9 shows a double pole switch formed from two single pole switches similar to the switch shown in Fig. 3, the two single switches being operated by a single bellows. The central bellows |52 when compressed forces gas from the two chambers formed by the inner shells I0 and forces the pools of mercury. 20 at the inner ends of these shells through an orifice and along grooves formed in insulating bodies I6 so that this mercury 26 will contact the end walls of the outer shells I2. Terminals 22 and 24 are provided on the inner and outer shells i6 and |2 respectively, so that when the mercury pools 29 have been forced from the inner shells the inner and outer shells of each pair are electrically connected. Any type of power circuits may be closed by these simultaneously acting switches.

Figs. 10 and 11 show a form of the invention in which a Siphon connection is provided through which mercury is forced from inoperative to operative switch closing position. Two metal tubes |96 and |98, one within the other, are supported in position and suitably insulated from each other as shown. A channeled block of insulating material 206 is inserted Within the lower end of the outer tube |96, the block having a central depression and radially extending channels. Extending into the lower end of the inner tube |96 is a Siphon 262, the upper end of which is within a pool of mercury 264 and the lower end extends partially within the central depression in block 260. A heating resistance 296 is provided within the upper end of the inner tube |98 so that when the gas within the inner tube is increased in pressure by heating this resistance, or by any other means, mercury 204 will be forced from the inner tube |98 through the siphon 292, which is preferably of non-conducting material, into the depression and radial channels within block This electrically connects the tubes ld and 93, both of which are provided with terminals for power circuit. When the gas within tube i99- again cools the reduced pressure therein draws back the mercury 294 through the siphon and disconnects the two tubes electrically from each other. Above the siphon 292 is a diaphragm 298 having a small central opening therethrough to prevent mercury from entering the upper end or" the tube |98 when the unit is turned to any position.

By means of this type of switch employing a Siphon 292 the switch is not closed until enough mercury has been forced into the siphon to complete the flow of mercury therethrough. When the flow of mercury through the Siphon starts by the greater weight of mercury in the branch leading to the lower opening, the flow will continue to f assure completion of the switch closing action.

What I claim is: 1. A fluid operated switch comprising two electrically conducting casings filled with a gas, said.

casings being one within the other and normally insulated from each other, means to change the pressure of said gas within one of said casings, a connection between said casings, and conducting iluid normally retained within one of gas filled casings and movable when the pressure of said gas is changed into a position partially fill ing the other of said casings and electrically con necting terminals secured to said casings.

2. A fluid operated switch comprising two metal casings filled with a gas, said casings being one within the other and normally insulated from each other, means to heat the gas within one of said casings, and a quantity of conducting fluid retained in one of said casings when both casings are at the same temperature, some of said fluid being forced into the second casing when said first casing is heated, whereby said casings are electrically connected when said first casing is heated and a portion of the fluid is forced into the second casing.

3. A fluid operated switch comprising two metal casings one within the other and both casings being lled with a gas and normally insulated from each other, means to change the pressure in one of said gas filled casings, a connection permitting communication between said casings, and a quantity of conducting fluid normally retained within one of said gas filled casings, said fluid being movable when the pressure of said gas is changed to a position electrically connecting terminals secured to said casings.

4. A fluid operated switch comprising 'two metal casings filled with a gas, said casings being disposed one within the other and normally insulated from each other, means to heat one of said gas filled casings, a connection between said casings, a channelled member of non-conducting material in the other of said casings, and conducting fluid partially in said channelled member and partially filling one of said gas filled casings, whereby when said gas in one casing is heated said conducting fluid is forced from said heated casing to said channelled mem ber and into contact with the other of said casings to electrically connect the two casings.

5. 1n a fluid operated switch, two casings filled with a gas, one or" said casings being metal and connected to an electrical terminal, said casings being positioned one within the other, means to change the pressure of the gas in one of said casings, a plurality oi switch contacts, and a conducting :duid normally retained within one of said casings, said fluid being forced into the other of said casings and successively into electrical connection with said switch contacts when said gas is increased in pressure.

6. A fluid operated switch comprising two casings iilled with a gas, one of said casings being metal and connected to an electrical terminal,

said casings being positioned one within the other, means to increase the pressure of gas in one of casings, a member formed of nonconducting material inserted between said casings and having a channel provided with a pluralty of depressions, a conducting fluid within said member ol non-conducting material and contacting the metal casing, whereby said fluid forced successively into said depressions when said gas ls increased in volume, and individual terminals dipping into said depressions whereby when said gas is heated said terminals are successively contacted by said conducting fluid.

7. A iluid operated switch comprising two casings, one within the other and the inner casing being formed of conducting material, a gas within aid casings, means to change the pressure of h gas in one of said casings, a channelled part .i non-conducting material within the outer i f and a quantity of conducting liquid normally within the inner casing, a connection beween said casings whereby when the gas pres- Mure within the casing containing the conducting liquid is increased liquid is forced from said inner casing into said channelled part, and electric terminals within said outer casing whereby when liquid is forced into said channelled part said liquid successively connects said electric terminals.

8. A fluid operated switch comprising two metal casings one within the other and both casings being filled with a gas, said casings being normally insulated from each other, means to change the pressure in one of said gas filled casings, a connection permitting communication between the lower ends of said casings, a quantity of conducting iluid normally retained within one of said gas filled casings, said fluid being movable when the pressure of said gas is changed to a position electrically connecting terminals secured to said casings, and means to retain said fluid within the lower end of said inner casing.

ARTHUR S. DYSART.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 375,403 Waterhouse Dec. 27, 1887 1,106,907 Wilkinson Aug. 11, 1914 1,596,964 Goodhue Aug. 24, 1926 1,647,595 Weeks Nov. 1, 1927 1,674,489 Vickery June 19, 1928 2,012,491 Agnew Aug. 27, 1935 2,047,902 Eitzen July 14, 1936 2,124,626 Mishelevich July 26, 1938 FOREIGN PATENTS Number Country Date 20,554 Great Britain 1904 621,128 Germany Nov. 1, 1935 664,449 Germany Aug. 27, 1938

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