USRE19235E - Electrical apparatus - Google Patents

Description

July 10, 1934.

L. A. M. PHELAN AL ELECTRICAL APPARATUS 23. 1922 2 Sheets-Sheet 1 Original Filed Dec he/an trill Cit/Edge y 1934- Y LA. M. PHELAN ET AL 19,235

ELECTRICAL APPARATUS Original Filed Dec; 2:. 1922 2 Sheets-Shae? 2 'IIIIIII A Reissues] July Our invention relates to electrical switches de-, signed particularly for the regulation or control of electrical circuits, such as may be used in connection with heating, cooling or and systems.

The subject matter 0 ELECTRICAL mmros Louis A. M. Phelan, Chicago, IlL, and Cliilord Hotchkiss, Elkhart, Ind., assignors, by mesne assignments, to Minneapolis-Honeywell legulator Company, Minneapolis, Minn, a corporation of Delaware Original No.'1,676,921, dated July 1c, 1928, Serial No. 608,703, December 23, 1922. Application l reissue July 9,

1930, Serial No. 486,896

as Clainu. (o1. soc-139) tainer is prop rly actuated.

edtomechauicalabuseandwhenimedinconnection with considerable quantities 0! electric.

tactor oi the above mentioned type, mounted in coniimction with an expansible and contractible element, such as heat or pressure responsive dealarm apparatusthis invention has reference to a device making use of a liquid electrical .contactor tube, which comprises a container in which'are mounted spaced electrodes adapted to be bridged'by a body of mercury when the con- Flg. 5' shows a modification having still another type'of casing or housing;

Fig. 6 is a detail sectional view similar to Fig. 3, taken along theline 6-6 of Fig. 'l, but showing a modified form of thermostatic element and contactor tube;.

Fig. is'a front view of and,

Figs. 8 and 9 are detail sectional views of huther modifications.

the device of Fig. 6;

In a general way our invention, as shown in Our invention makes use of an electrical con- Fig. 1, comprises the liquid contactor tube I mounted upon a conical spiral thermostatic bimetallic element 2, which in turn is pivotally mounted at 3 to the frame or support 4. A cover vices, .or as curved pressure tubes and thermo- '5 serves -to protect and enclose the device.

static elements. The pressure responsive or thermostatic element is designed to support and serve to actuate the electrical contactor. into or More particularly our device refers to anelectricswitchotthistypeinwhichthepressureor thermostatic element is unusually emcient, ac-

curate and rapid in operation.

. A'iurther particular object of our invention is topmvideareadymeansioradiustingtheabove operate at predetertypefotde'viceto Another -readiiy energy will object oi our invention -tubeottheabov echaracter, which upon an actuating dea very small quantiiw contactor tube and require only a small change in prestemperature for its actuation. I

object of our invention is to provide switchdeviceoithetypeindicatemthatwillbe and economical to construct and which will possess great durability, even when subjectmoimted available for actuating the current at substantial voltages.

Also further objects and advantages wlllappear from the following specification and accompanying drawings, in which- I Figure 1 is an elevation view partly in oi my invention;

Fig.2isasectionalviewtakenonline22oi Pia-1:

I'lg.3isadetailsec modification having a is to produce a tionalv iewtaken The tube 1 is constructed in 'a substantially toroidal form, preferably in the form of a torus.

the tube is evacuated and filled with aninert gas and sealed oil through the tip 6. Electrodes the tube and may be formed oi. platinum or o! Dumet wire covered or plated with casings of pure iron or the like metal which is unafiected' by the arcing obtaining in the tube in the presence of the mercury and the mercury vapor. A body of conducting fluid 9, preferably mercury, may substantially.fill the lower half of the container 1- and is normally in contact with the electrode 8. When the tube is tilted in the proper direction,

relation with the electrodes-7 and. 8, thusclosing an electrical circuit through the tube.

' Since the tube is oi toroidal term and is mounted to be tilted substantially about its geometrical axis, it will be noted that the body of mercury 9 will remain practically stationary and .of constant-shape whenthe tube is tilted into or out of circuit making podtion. Inother womathebodyoioonductingfiuidaaswell as the tube 1, retains substantially statimiar'y center oi gravity-when the tube is actuated. Hence it is obvious that very little. energy is requiredeithertoinitiallymovethetube orto returnthetube toitsnormalpositiomsincethe parts remain practically balanced at all times. In the former types of-liqui'd contactor tubes, it hasbemnecemarytodisplaceafairlylargemam Such contactors have the further disadvantage that an appreciable temperature obs-n8 is requiredto restorethepartsincluding the'bodyoi conducting liquid to their normal position after .onee

on line the bodyci mercury 9 will come into bridgingofheavyliquidinordertoactuatethedeviee.

After the various parts in the tube are in place,

'7 and 8 are inserted and sealed in the walls of for mounting the of a bi-metallic ribbon composedof layers of any suitable metals or alloys, such as brass and nickel, and is wound substantially in the shape of a conical or helical spiral as shown. This form of winding has a particular advantage over. the more usual simple spiral form in that a much larger portion of the surface area of the thermostatic ribbon or heat responsive element is directiy exposed to the atmosphere and air cur,-

rents. This is an important consideration when this type of device is used for accurate and rapid temperature regulation. This form; of conical spiral mounting has a further advantage in the present structure, in that it .makes possible a more convenient arrangement of thelead wiresto the contactor tube and permits the contactor.

tube to be flexibly mounted at a central position in the casing remote from, any of the fixed parts of the structure which would possibly hit against and break the glass tube.

The inner end of the 'spiral element 2 is mounted upon a pivoting shaft 3 which is retained in a frame 4 by a nut 3a and washer 3b. A collar 11 surrounds the pivoting screw 3 and is fixed to the spiral element 2 by solder or by means of a screw 12.

The collar 11 is provided with an extension 13 which forms a handle for adjusting the angular positionof the tube land the spiral element 2 about its pivoting shaft 3. The handle 13 extends to the exterior of the casing and is provided with a pointer 14 co-operating with a calibrated scale 15 formed on an extension of the frame 4.

The electrodes '1 and.8 are connected in the circuit, respectively, by the flexible lead wires 16 and 17. The flexible wire. 16 is attached to the outer end of the spiral element 2 so that the electric current flowing in the circuit will trav-- erse this element for the particular purpose hereinafter described. From. the spiral element 2' the circuit continues through frame 4 to a bind-' ing post 19. The flexible lead 17 is connected to a binding, post 20. The binding posts 19 and 20 serve to connect the device to the desired externalcircuit.

The cover 5 is attached to the frame 4 by means of lugs 21 formed integral with the lower end of the frame 4 and by a lug 22 formed at the upper end of the frame 4 and engaged by a screw 23. Openings 24 are provided in the cover 5 for the 1 purpose of permitting free circulation of aircurrents about the thermostatic element 2. The

cover 5 is provided witha thermometer 25 which serves as a guide when adjusting the switch to actuate at a desired temperature.

Screw holes 26 may be provided in the frame 4 device upon a wall or partition In Fig. 4, the device is shown mounted in a modifled form of The casing here consists of a-body portion 2'! and a cap portion 28 having a flange 29, which is intended to be mounted flush with a wall surface. In Fig. 5, the device is shown mounted in another modified form of easing, comprising a rear enclosing frame 30, a mounting plate 31, and

.a cover portion 32. The rear frame 30 constitutes a weather-proof connection box for the .'electrical leads and is provided with a threaded opening for a conduit connection.

In Figs. 6 and 7, a modified structure is shown in which a cylindrical contactor tube 36 is used. The tube 36 is designed to be normally located in a position neighboring the horizontal and upon being tilted, a body of mercury 37 is designed to flow into and out of bridging relation with a pair of electrodes 38 and 39 which are connected in circuit in the manner of electrodes 7 and 8 above described. A contactor tube of this type has been found to be accurately responsive to very slight changes in its angular position and consequently is desirable for use'where only small changes in temperature occur. The

tube 36 is mounted upon a spiral element 40 by means of a. spring clip 41. It will be noted that the spiral element 40 is shown in an inverted position from that shown in Fig. l, in order to accommodate more readily the cylindrical type of contactor tube; The spiral element 40 is attached by means of rivets 42 to a supporting arm 43. a

In Fig. '8, a further modification is shown in which a hollow spiral thermostatic element 44 is'used. The hollow portion of this spiral element may form a continuous passage throughout the length of the spiral and may be connected at an end, if desired, with a container 45. The passage through the spiral element and the container 45 may be fllled with air or other fluids,

which when heated will result in a'- change in pressure. This pressure change will serve to alter the shape of the spiral element 44 and thus actuate the contactor tube. It will be understood that container 45 is merely disclosed as an e xample of a source of pressure changes and that the contactor tube and spiral element shown in Fig. 8 are capable of use with, and may be actuated by, other desired sources of varying pressure.

In Fig. 9, a modification is shown embodying features shown in Figs. 3 and 8. A hollow spiral element 46 is shownhaving outer and inner walls 46a and 46b composed respectively of materials having difl'erent coeihcients of expansion. This spiral elementmay also be attached to a source 7 of variable pressure, such as the fluid container 47 and hence this element issubject to an alteration in shape when temperature changes occur, both because of its bi-metallic nature and because of its action as a curved pressure tube.

mail of the above described structures it will be noted that the use of hearings in the operating parts of the mountings ofthe contactor tubes is entirely eliminated. Consequently the spiral elements when actuating 'the contactor tubes,

are not required to overcome any variable frictional lomesas would result with the use of bearings.

The operation and one method of using the device of Fig. 1 will now be-outlined. The binding posts 19 and-20 are connected directly in series with the circuit which is to be controlled such, for example, as the circuit of a motor controlled heating q efit of any of the usual and suitable UP that the room temperature is at or near the desired point, the lever 13 is turned so that the contactor tube-1 isin a substantially neutral pofltion ready to either close or open the circuit with a very slight change .of temperature.

If it is assumed the device is being used for heating apparatus should not be in full operation and consequently the contactor tube-should be in open circuit position with the body of mercury 9 out of contact with the electrode '7.

However, as the room temperature drops a predetermined amount. the thermostatic element 2.

will become modified in shape because of the ternperature change and will rotate the contactor tube 1 about its axis into circuit closing position. The current to the contactor tube will now flow through the spiral element 2 and. will start the operation of the heating equipment. The spiral element 2 will thereupon begin to return to its normal position and will begin to rotate the contactor tube back to itsformer position as a result of two causes: first, the heatingequipment will have partially restored the room temperature and second, the current running through the spiral element will furnish a slight amount of heat, thus aiding in quickly bringing the temperature of the spiral element 2 back to normal.

This current heating efl'ect obtaining in the element 2 has a particular advantage in this type of heat regulating switch which will now be outlined. When the contactor tube 1 turns to its closed circuit position it will tend to remain there for a slightly longer period thannecessary due to'inertia of the heating apparatus and to the timeirequired to bring the room temperature and the temperature of the thermostatic element back to normal. This will result in a room tempei'ature in excess of that desired before the thermostatic element is sufilciently heated to cause the heatingequipment to be shut oii. Hence, in order to use this type of regulating switch where the temperature must be regulated very accurately, it is advisable to supplement the action of the increased room temperature upon the spiral element 2 with the heating action of the current flowing through this element. With such a device it has been found possible to regu-- late the room temperature with an accuracy several degrees closer than with the former methods However, in case this type of thermostatic switch is used in connection with the control of refrigeration orcooling apparatus, it will ordinarily be connected in circuit and adjusted to open the circuit upon the occurrence of a sub ficient drop in temperature- This is the opposite of its action when used with heating apparatus .where it serves to open the circuit upon the occurrence of 'a sufiicient increase in temperature. In, view of these facts, the heating effect of the current through the spiral element is not required' in the case of refrigeration and cooling apparatus. Consequently in the device as shown in Fig. 4, the current is not connected through the spiral element but independent lead wires 16a and 170 are. provided to the binding posts. In other instances it may be desirable'to pass only a'portion of the total current through the spiral element and in such cases a shunt wire 16b, as shown in Fig. '5, maybe so designed to by-pass the desired amount of current;

The terms contactor', "li uid contactor. and electrical contactor as employed in the claims contained herein refer to the well known type of mercury electric switch or an equivalent there-.- of which comprises an hermetically sealed con-- tainer having electrodes disposed therein and a body of conducting liquid, such as mercury,.which serves to make and break the electric circuit between the said electrodes. The various modithe regulation of heating equipments and that the room is at the desired temperature, then the fications of our invention shown in the drawings are illustrative of several types of such contactors as are covered by our present invention. It is obvious, therefore, that the'above-mentioned terms do not pertain to an open and exposed contact member which is movable by the coiled thermostatic element and which is adapted to control an" electric circuit by cooperating with a second and fixed open contact member.

While we have shown and described several embodiments of our invention, it is to be understood that manymodificationsmay be made therein without departing from the spirit and scope of the appended claims, and we desire that only such limitations shall be imposed upon our inventlonas are specifically pointed out in the claims and such as are required by the prior art.

Having thus described ourinvention, what we 7 claim as new and desire to secure by Letters Patent in the United States, is:

"1. An electric switch comprising a coiled expansible and contractible element, a liquid contactcr wholly supported on and movable with said element, 'a body of conducting liquid housed in said contactor, and an adjustable supporting means for said elementfor adjusting the position of said contactor.

.2. A thermostaticswitch comprising a heat responsive element formed of conducting material,

and a liquid contactor comprising a container, oo-

operating electrodes sealed therein and a conducting body housed in said container, said contactor being wholly supported upon one end of said element and one of said electrodes being electrically connected in circuit relationship to said element.

3. A thermostatic switch comprising a heat responsive element formed of conducting material, and a liquid contactor comprising a container, cooperating electrodes .sealed therein and a conducting body housed in said container, said con-' tactor being wholly supported upon a free end of said element, and said element being electrically'connected to one of said electrodes whereby the current that may .fiow in said circuit serves to heat and thereby tends to actuate said element'.

' '4. An electric switch comprising an expansible andcontractible element, and an electrical ll uid contactor, including co-operating electrodes of opposite polarity, said element being fixed at one s end and free at its other end and said electrical trical liquidcontactor, including cooperating electrodes of opposite polarity, said element being fixed at one end and free at its other end and said electrical liquid contactor bei g wholly supported upon said free end, and means for adjusting the angular position of said element and said cohtactor.

6. An electrical switch comprising acoiled tube filled with a volatile fluid, and a rotatable electrical contactor, said tube being fixed at one end and its other end being free to impart movement as said tube expands and contracts, and said contactor being mounted immediately adjacent to said other end and connected directly thereto so as to rotate about the axis of said tube.

- 7. An electric switch comprising a coiled expansible and contractible element, a liquid contactor mounted at the inner end thereof and tiltable about the axis of said coiled element, and

element, said supporting means being in turn pivotally mounted in order to provide for adjustment of the angular position of "the said liquid contactor.

' 8. An electric switch comprising a coiled expansible and contractible element, a liquid contactor mounted on the inner end thereof, and adjustable supporting means having in turn a mounting pivoted substantially coaxially with said coiled element in order to provide foradjustment of the angular position of said liquid contactor,

9. A thermostatic switch comprising a heat responsive element, a liquid contactor operable.

upon being tilted and wholly supported on the free end thereof, and supporting means fixed to the other end of said element, said supporting means being pivotally mounted in order to provide for adjustment of the actuating position 01' said liquid contactor.

10. An electric switch comprising an expansible and contractible element, amounting towhich one end only of said element is fixed, atiltable contactor mounted and wholly supported upon the other end of said element, said contactor comprising a container, electrodestherein and a conducting body movable therebetween, and means for adjusting the tilting angle of said contactor.

11. An electric switch comprising an expansible and contractible element in the form of a substantially conical spiral, the end of said element at the base of the conical spiral being fixed, and an'electrical contactor wholly and tiltably supported upon the end 01 said element at the apex of the conical spiral 12. A thermostatic electric switch comprising a coiled thermostatic element having only one of its ends fixed, a liquid contactor operable on'being tilted and supported wholly upon the other end of said thermostatic element, and means for v adjusting the angular position of said liquid, contactor thereby permitting said thermostatic element to tilt said contactor at predetermined temperatures.

13. A thermostatic switch comprising a coiled thermostatic element having only one of its ends fixed, a liquid contactor operable on being tilted wholly carried by and mounted upon the free end of said thermostaticelement, and means for adjusting the angular position of said liquid contactor to permit said thermostatic element to operate it at difierent predetermined temperatures.

14. An electrical device comprising a coiled expansible and contractible element, a mounting ,member, 'a bracket mounted on said mounting member and having one end only of said element secured thereto, a liquid contactor operable on being tilted and mounted at the other end of said element, said bracket being adjustable for vary ing the angular position of said liquid contactor thereby permitting said element to operate said liquid contactor under predetermined conditions.

15. An electrical device comprising a spirally coiled expansible and contractible element, a mounting member, a bracket adjustably pivoted upon said mounting member, the outer end of said element being secured to said bracket, and a liquid contactor mounted at the inner end of said element at its 'axis and connected to said inner end whereby movement'is imparted thereby to actuatesaid liquid contactor.- g

'16. An electrical device comprising a coiled expansible and contractible element, a mounting member, a bracket pivoted upon said mounting member, one end of said coiled element being semounted at the other end'oi. said element and connected thereto whereby movement of said other end may be imparted to; said liquid contactor for tilting the latter.

17. ,An electrical device comprisinga coiled actuatin'g element, a mounting member a bracket adjustably secured to said mounting member, one end of said element being secured to saidbracket, and a liquid contactor wholly supported uponan carried by the free end of said element. 7 18. A thermostatic switch comprising a thermostatic coil, a mounting member, a bracket pivotally secured to said mounting member, the outer end of said coil being attached to said bracket, and a liquid contactor wholly supported upon the free end of said coil. 19. An electrical device comprising a' thermostatic spirally coiled element, a mounting memher, a bracket pivoted thereto, the outerend of said element being attached to said'braeket, and.

a liquid contactor disposed at the axis thereof, said contactor being wholly supported upon the free end of said element.

20. A thermostatic switchcomprising-a coiled -actuating element, a liquid contactor operable upon being tilted and mounted upon the free end of said coiled element adjacent to the axis then.- of, and supporting means to which the other end of said coiled element is attached, said supporting means being adjustable to provide for a djustment of the tilting {angle of said contactor.

21, An electrical device comprising a thermostatic coil, a liquid contactor operable upon being tilted and mounted adjacent to the axis thereof and wholly supported upon the free end ofsaid coil, supporting means to'which the other end of said coil is secured, said supporting means being adjustable in order to provide for varying the actuating position of said contactor, and electrical connections for said contactor said coil as a part thereof. 4 .22. An electric switchcomprislng an actuating element having only one end thereof fixed, a tiltable liquid contactor being mounted and wholly supported upon the free endof said element, said contactor comprising a container,

electrodes therein and a conducting body movable therebetween. and means for adjusting said actuating element whereby the tilting angle of said contactor for opening, and closing its associated electric circuit may be varied.

' 23. An electricswitch comprising a heat responsive actuating element having only one end thereof fixed, a tiltable contactor mounted and wholly supported upon the tree end-of said ele end of said element is fixed, a tiltable contactor constituting secured to and wholly supported upon the free end of saidelement, said contactor comprising a container, electrodes therein, and a conducting body mova 1e therebetween, and means'for adlusting sai thermostatic element" whereby the tilting angle of said contactor may be varied.

25. An electrical switch comprising a coiled expansible and contractible element, and a rotatable electrical contactor, said element being fixed at one end and being free at its other end toimpart movement as said element expands and contracts and said contactorbeing mounted immediately adjacent tosaid other end and connected directly thereto so as to tilt about the axis of said element by the movement imparted byLsaid other end. v a

26. An electrical switch comprising a coiled expansible and contractible element, an electrical contactor, said element being fixed at" one end and being free at its other end to impart movement as said element expands and contracts and said contactor being mounted-adjacent to and tiitable about the axis of said element and being tiltable by the movement imparted by said other end, and adjustable means for varying the position of the fixed end of said element for varying the tilting angle of said contactor.

27. An electrical switch comprising a spirally coiled expansible and contractibie element, an electrical contactor mounted adjacent to and tiltable about the axis of said element, said element being fixed at its outer end and being free at its inner end to impart tilting movement to said contactor as said element expands andcontracts, and means for adjusting the position of the fixed outer end of the said element thereby varying the tilting angle of said contactor.

28. An electric temperature control switch comprising a heat sensitive element responsive primarily to the ambient temperature to be controlled, an electrical contactor, a holder therefor adapted to be moved in response to temperature changes to which said heat sensitive element is subjected, and means for additionally thermally influencingsaid heat sensitive element through the medium of the electric current flowing through said electrical contactor.

29. An electrical temperature control switch comprising a heat sensitive elenient responsive primarily to the ambient temperature to be controlled, a member associated therewith and moved thereby in response'to temperature changes to which said heat sensitive element is subjected. and an electrical contactor carried by said member, said heat sensitive element being thermally influenced additionally by the current flowing through said electrical contactor and said additional thermal influence being discontinued when said electrical contactor moves to open circuit position.. v

30. A control mechanism for maintaining the temperature of an ambient medium substantially uniform comprisingin combination with electric switching means, of a temperature respon-' sive device responsive primarily to the temperature of the ambient medium which temperature is to be con lied to substantial uniformity, and means opera vely connecting said device and said switching to one positiomg said device when the latter responds to a c e in one direction of the temperature of the ambient medium for maintaining said-temperature within the normal range to establish substantial uniformity thereof, such operation of the switching means also controlling the transmission of auxiliary heat to' said device whereby said devicewill respond to the combined effect of the temperature of'the ambient medium and the auxiliary heat to operate the switchingmeans to its other position at a different point in the range of the ambient temperature than would.

be the case if the device was responsive only to the temperature of the ambient medium to the exclusion of the auxiliary heat. I

31.'A control for maintaining the the latter 'being operated temperature of an-ambient medium substantially uniform comprising in combination electric switching means, and a thermal actuatorprimarily responsive to the temperature of the ambient medium operatively connected to said switching means and'adapted to move the same to circuit opening and closing positions in response to changes in the temperature of the am-.

bient medium under control, actuation of said switching means to one of its positions being effected solely by the temperature of the ambient medium and when moved to said position then controlling the transmission of auxiliary heatto said actuator whereby the switching means will be operated to its other position in response to the combined action upon said actuator of the auxiliary. heat and the temperature of the ambient =m'edium under control.

32. A control mechanism for maintaining the temperature of an ambient medium substantially uniform comprising in combination electric switching means, and a thermal actuator responsive primarily. to the temperature of the ambient medium to be controlled and operatively connected to said switching means for actuating the same to circuit opening and circuit closing positions, the 'said actuator solely operating said switching means to both positions by reason of its physical distortion arising from its own temperature, movement of said switching means by said actu ator to one of its positions being effected solely by the temperature of the ambient medium whereby when said switching means is moved to said first position the transmission of ,auxiliary' heatto said actuator is controlled whereby it then becomes responsive to the combined action of the temperature of the ambient medium to be controlled-and the auxiliary heat for moving said switching means to its other position.

33. A control device for maintaining the'temperature of an ambient medium substantially uniform comprising in combination electric switch ing means, and a thermal device influenced primarily by the ambient temperature beingoperatively connected thereto for actuating the same,

said thermal device moving said switching means -to circuit closed position solely as a result of a fall in the ambient temperature to be controlled to restore said temperature to substantially normal value, the closing of said switching means, controlling an auxiliary supply pf heat to said device whereby it"actuates said switching means to open position as a result ofthe combined action of a rise in the ambient temperature to be controlled and the auxiliary heat.

34. A control device. for maintaining the temperature of the ambient mediumsubstantially uniform comprising in combination a thermal device primarily influenced by the ambient temperature, andelectric switching means actuated thereby, said thermal device solely by reason of its own physical distortion moving said switching means to closed position when the ambient temheated for influencing said thermal device whereby the switching means is actuated to open posielectric circuit comprising a heat operated element including. a thermostatic metallic coil, a circuit closing device including a tiltable vessel, terminals and a fluent conductor therein, means intermediate said circuit closing device and said heat operated element for operating the former to break the circuit by the heat expansion of the latter and means for varying the point at which the said intermediate means will cause circuit breaking movement of said device without changing the relative positions 01 said device and said tion beiorethe ambient temperature of the space element. to be heated rises to that point at which said LOUIS A. M. PHELAN. switching means would otherwise be opened. CLIFFORD HO'IUHKISS.

36. A thermostatic device for controlling an DISCLAIM-ER- Re. 19,235.Zouis A. M. Phelan, Chicago, Patent May 28, 1941, by the assignee, 17w

ELECTRICAL APPARATUS.

111., and 011370112 Hotchkiss,Elkha1-t, Inddated July 10, 1934. Disclaimer filed Brown Instrument Company.

' Hereby enters this disclaimer to claims 31, 32, 3s, and 35 in said specification.

[Qflic'ial 0am June 24, 1941.

heated for influencing said thermal device whereby the switching means is actuated to open posielectric circuit comprising a heat operated element including. a thermostatic metallic coil, a circuit closing device including a tiltable vessel, terminals and a fluent conductor therein, means intermediate said circuit closing device and said heat operated element for operating the former to break the circuit by the heat expansion of the latter and means for varying the point at which the said intermediate means will cause circuit breaking movement of said device without changing the relative positions 01 said device and said tion beiorethe ambient temperature of the space element. to be heated rises to that point at which said LOUIS A. M. PHELAN. switching means would otherwise be opened. CLIFFORD HO'IUHKISS.

36. A thermostatic device for controlling an DISCLAIM-ER- Re. 19,235.Zouis A. M. Phelan, Chicago, Patent May 28, 1941, by the assignee, 17w

ELECTRICAL APPARATUS.

111., and 011370112 Hotchkiss,Elkha1-t, Inddated July 10, 1934. Disclaimer filed Brown Instrument Company.

' Hereby enters this disclaimer to claims 31, 32, 3s, and 35 in said specification.

[Qflic'ial 0am June 24, 1941.

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