US2604266A - Combined thermostat and automatic pilot control - Google Patents

Description

July 22, 1952 w. F. JACKSON 2,604,266

COMBINED THERMOSTAT AND AUTOMATIC PILOT CONTROL Filed June 11, 1949 2 SHEETSSHEET 1 IIIIIIIIIIIEF'" IIII IIIII-I l 19 60 kgfi I J9 ON INVENTOR.

4:50.9 FT Jac/rsoM' ATTORNEY.

y 22, 1952 w. F. JACKSON 2,604,266

COMBINED THERMQSTAT AND AUTOMATIC PILOT CONTROL Filed June 11 1949 2 SHEETS-SHEET 2 8% INVENTOR. (0280 F J cKso/V.

' BY Jbzs ATTORNEY.

Patented July 22, 1952 COMBINED THERMOSTAT AND AUTOMATIC PILOT CONTROL Wilbur F; Jackson, Compton,

cane, assignor to Robertshaw-Fulton Controls Company, Greensburg, Pa., a

corporation of Delaware Application June 11, 1949, Serial No. 98,486

8 Claims.

- l Thisinvention relates to combination controls forg'aseous fuel burners wherein the temperature controlling device and the pilot cut-oil both operate upon a single control valve. In this respect the device is similar to that disclosed in U. S. Patent No. 2,361,945 to W. F. Jackson wherein the automatic pilot control embodied thermomagnetic means-responsive to extinguishment of the pilot flame for causing thecontrol valve to close in the event it was being held open by the thermostat.

The present invention is characterized by a movable electromagnet which picks up its armature in response to energization by the thermoelectric device and returns to its initial position upon completion of this resetting operation. The single control valve is thus free to be moved between closed and open positions by the thermostat which may be of the rcd-and-tubetype operating through snap-action mechanism. However, when the pilot flame is extinguished and the thermoelectric device cools thenthe armature is released and returns under spring bias to its initial position. The return movement of thearmature is in .a path substantially coaxial with the valve member so that the latter is moved to closed position should the thermostat be holding it open.

The provision of the movable magnet reduces the number of parts required for safe operation during resetting. Moreover, the separate armature and control valveconstruction retains intact the majority of features found advantageous in prior devices of this general type. Among these may be mentioned the provision for automatic shut-off of the main burner fuel in the event of pilot flame failure; the single valve for dual control purposes which is not subjected to damage when the automatic shut-elf occurs; the safeguard against sticking valves which may occur where a separate cut-off valve is provided and infrequently operated; and the safe-lighting feature provided by preventing flow of fuel to the main burner during the resetting operation.

In the accompanying drawings:

Fig. 1 is a plan view of the control device of thisinvention;

Fig. 2 is an elevation Fig. 3 is a side elevation;

Fig. 4 is an enlarged sectional view taken on the line IV-IV of Fig. 1; and

Fig. 5 is an enlarged sectional view taken on the line V-V of Fig. 3.

' Main shut-o1? cock Referring more particularly to the drawing the 2 control device comprises a casing I0 provided at one end with a lateral inlet opening I2 for fuel and at the other end With an outlet opening I4 which .is adapted to be connected by suitable piping with the main or heating burner of a water heater or other appliance (not shown).

A valve chamber i 5 is positioned in the body l0 intermediate the inlet I2 and outlet I4 and passage of fluid, such as gaseous fuel, between the inlet I 2 and the valve chamber I3 is under control of a main shut-off cock I8. As shown more clearly in Fig. 5, the shut-off cock I8 is provided with an angular port 28 which is movable upon rotation of thecock Iii by the usual knob I9 to open and close communication .between the inlet I2 and thevalve chamber I 6.

Pilot shut-017 cock ,A pilot passage 22 communicates at one end with the inlet I2 adjacent the main shut-off cock I8 and the passage of fuel therein is under control of a pilot shut-off cook 24. An outlet 26 is provided in the body I0 for connection to a conduit 25 leading'to the pilot burner of the appliance 27 when an angular port 28 in the pilot shutoff cook 24 is rotated therewith by the usual knob 29 to open position.

Control valve mechanism A partition 36 projects from opposite walls of the valve chamber I6 and provides a support for an annular valve seat member 32 therein. An axial hollow boss 34 is formed within the annular valve seat 32 and provides a bearing for a hollow valve stem 36 for relative slidable movement thereof: A disc valve member 38 is mounted on the valve stem 36 for movement therewith between open and closed positions relative to the seat 32. The valve member 38 is normally biased.

toward the seat 32 bymeans to be described more fully hereinafter. Suitable ports 40 extend latera'lly through the valve seat 32 to provide communication between the, valve chamber I6 and the'outlet I4 when the valve member 38 is in open position.

The hollow valve stem .36 contains an override mechanism comprising a plunger 42 and biasing spring 44 which serves to urge a collar 46 on the plunger 42 into engagement with a bushing 48 closing the inner end of the hollow valve stem 36., The lunger 42 projects through ,thebushing 48 for operative engagement with a clicker mechanism of well-known form including a thrust element 50 which is biased within'the' annular valve seat 32 for imparting snap-action movement to the valve member 38.

Temperature regulation able cap element 56 which is .carried'in the valve; body [0. The opposite side of the cap element 56" engages with the thrust element 50. of the, clicker mechanism for operating the same as will hereinafter be apparent. Suitable meansior mount:- lng the control in the water heater or other appliance is provided by an elongated boss 58fprojecting from the body around the rod-and.- tube element 52, 54. The temperature at which the.valve member 38 will beoperated may be adjusted by. means-of the" usual lever 60carried by therod'54 and .manuallyioperable for-rotating the ro'd52:relative.to the-tube 54- as'previously explained. It willbe'understood that otherwellknown thermostatic devices may-be substituted including the hydraulic or liquid-type if' desired.

Automatic pilot control.

Thermoelectric means areprovided for moving the valve member 38ft0- closed position in the event of "extinguishment' ofthe pilot'burner'flame and irrespectiveofthe thermal condition ofthe thermostat. To this end, a magnet housing 62 is mounted on the body In on the side opposite the connection 58-andextending coaxially with the valve member 38. The interior of the magnet housing 62 communicates with the interior of the body I0 defined by the valve chamber l8 and a flexible sealing'disc64 extends across the interior ofthe housing 82at'its junction with the body l0 for: closing the communication therebetween. Thus, passage of fluidfrom the'valve chamber l6 t'o'the magnet housing '62. is prevented. The sealing disc 64 carries; a spring retainer 6.5 secured thereto byan axially located plug" or rivet 66; A coil spring 61 is operative between the valve member 38 and the retainer 65' andserves to bias the valve member:38 toward theseat 32 a previously indicated.

'A magnetcover. B'Biis mounted .within the housing 62for slidable movement therein toward and. away'from the sealing disc 64. The. cover 68- is. biased-toward the. outer end of the magnet housing 62" by a coil' spring inoperative between the. cover 68. and the housing. 62'. A'nelectromagnet comprising, ahorseshoe frame 14 is, seated on its. base 15 at one end of the cover 88andii's secured thereto by. a hollow rivet. 16. extending: through these members. The usualiwindingfla has one end secured in the hollow rivet.16 to providev a ground. connection as will be apparent hereinafter.. The'winding continues in theform of a pair of coils 19' around .the legs. ofthe horseshoe. magnet 14' although only one such coil is. shown in the drawing. The opposite end of.the.winding 18"extendsthrough'a suitable aperture in. the cover 68 to' the exterior thereof and. is formed. into a'loop8l between the end faceofthecover. 68'andjthe adjacent end. of the housing,62". The looped end is secured in a socket 83 for one end of'a' thermocouple 80, the opposite. endof which provides a hot. junction for exposure. to. the .pilot burner fiame.

An armature 82is supported. within the. magnet cover-68' on an armature stem 84 and isseparable from the pole faces of the magnet 14 during its movement between attracted and released positions. The armature stem 84 is slidably mounted in a hollow bearing member 85 on the cover 68 and projects therefrom into abutting engagement with the plug or rivet 66 on the seating disc 64. The armature 82 isbiased to .its released position by a coil spring 86=operab1e between the cover 68 and a retaining plate 88 carried on the projecting end of the armature stem 84. As the spring86 is considerably stronger than the valve spring. sufiicient force is exerted thereby on the valve member 38 to hold the same in its closed position relativeto the valve seat 32 whenever the armature 82: is disengaged from the pole faces of the magnet 14. It should be observed, however,. that the coil spring 18 is considerably stronger than the armature spring 86 for a purpose apparent hereinafter.

As is well known, the electrical energy generated bythe thermocouple responsive to heatingby, the pilot flame is insufficient to attract the armature 82 from its released position but-is-suffi.- cient to hold the same in attracted position after? the usual resetting operation has been conducted; Consequently, manual resetting means are-:employed to move the magnet Ill-into engagement. with the armature 82 andtake-the form of a resetting button 90which projects from the mag; net housing 6-2 and engages atits innerend with the rivet 16 on the magnet cover 68. A coil spring 92 is housed within thebutton 98 and-engages at its inner end with the magnet cover: 88- for biasing the button outwardly ofv the magnet housing 62; A head 94 is: formed on the-inner. end-of the button Qiifor cooperation with a suitably fianged end of the, magnet" cover -62 to,pre-- vent; ejection of the button- 90-therefrom1under bias of the spring 92.

Operation The'control device-isplaced in operativecondition by manual operation when the pilot burnerislighted and'thevalve'member 38- is normally; engaged with its seat 32. l8and pilot cook 24 areboth manually rotated to open position and fuel thereupon flows through the inlet 12 to the valve chamber l6-and to'the pilot outlet 26 The fuel issuing from the pilot burner 21 is-then lighted. The thermocouple has its-hot junction exposed to the pilot burner flame and-thereupon becomes heated and develops sufficient current to energize the-winding 18' of the electromagnet. The resetting operation is then conducted by manual pressure appliedto the button Sill-for moving the magnet cove1-68 and magnet T4- jointlyrelative to the armature 82. During this movement thecoil-spring Hi-is compressed, thebearingmember moves relativelytothe stem 84 and the coilspring 861s somewhat compressed as will be apparent. Itwill be observed that the winding 18- does not interfere with free movement of the magnet 14 due to the provision ofthe-loop: iil 'which also eliminates any strain on the electrical connections. When this portion of the resetting operation is completed, the armature 82 isfirmly engaged with the pole-faces ofthexmagnet l4.

Afterthe thermocouple develops sufil'cientcurrent to energize the magnet. 14,.the'reset button Sll'is released and the bias'of the spring Hr-serves to retract the magnet cover fiaandthe magnet 14 to their initial positions. However, the armature 82 is now carried along with-the magnet 14 against. the bias ofthe coil. springJQ- which The main shut-off cock remains somewhat compressed. The armature stem can thus no longer exert a force on the rivetfit carried by the sealing disc64 so that the valve member 38 becomes freed for movement to open position relative to the valve seat 32.

It should be observed, however, that movement of the valve member to open position cannot occur, due to the bias of the valve spring 67, until the thermostat 52, 54 is adjusted by manual operation of the lever 68 to a desired temperature setting and operation of the main burner is required by the thermal conditions sensed by the thermostat. The rod 52 exerts a force on the thrust element 53 and the clicker mechanism opens the valve member 33 against the bias of the valve spring 51. Flow of fuel from the inlet i2 through the valve chamber It and ports 40 in the valve seat 32 to the outlet 14 is now permitted and operation of the main burner in the usual manner can then occur. perature sensed by the thermostat 52, 54 reaches that for which the adjustment has been set, then closure of the valve member 33 occurs under bias of the spring ill and is permitted due to reverse positioning of the clicker mechanism as is well known to those skilled in the art. However, during this normal reciprocation of the valve member 33 in controlling flow of fuel to the outlet 14, the armature 82 remains engaged with thepole faces of the magnet 14.

In the event that the pilot burner is extinguished, then the thermocouple 86 ceases to generate current causing deenergization of the electromagnet and movement of the armature 82 away from the pole faces of the magnet 14. Such release of the armature B2 is due to the bias of the coil spring 86 and serves to bring the armature stem 34 into operative engagement with the rivet lit carried bythe sealing disc 64, thus causing closure of the valve member 38. As

previously indicated, such closure can occur re gardless of whether the thermostat 52, 54 is operating to hold the valve member 38 in open position due to provision of the override connection within the hollow valve stem 38. Thus, the bias of the override spring 44' is overcome upon release of the armature 82 due to the stronger bias exerted by the coil spring 86. The hollow stem 36 moves relatively to the plunger 42 during compression of the override spring 44 and without causing reverse operation of the clicker mechanism as in normal thermostatic operation.

It will be understood that many changes may be made in the details of construction and arrangement of parts to accomplish the purposes of this invention without departing from the scope of the invention as defined in the appended claims.

I claim:

1. A control device comprising in combination, a movable electromagnet having an armature separable therefrom for movement between attracted and released. positions, a valve member movable independently of said armature between open and closed positions and having operative engagement with said armature in said released position thereof, means for biasing said armature to released position to hold said valve member in closed position, thermoelectric means adapted for energizing said electromagnet but insufliciently to attract said armature from released position, resetting means operable for overcoming said biasing means and moving said electromagnet into engagement with said armature while maintaining said armature in operative engagement with said valve member, and

When the tem- 6 means effective upon completidn of the resetting operation for retracting said electromagnet and causing movement of said armature out of operative engagement with said valve member to free the same for movement between said open and.

closed positions.

2. A control device comprising in combination, a movable electromagnet having an armature separable therefrom for movement between attracted and released positions, a valve body having a seat spaced from said electromagnet, a valve member movable independently of said armature between open and closed positions relative to said seat and having operative engagement with said armature in said released position thereof, means operative from one side of said seat for biasing said armature to released posi-" tion to hold said valve member in closed position, yieldable actuating means operative from the opposite side of said seat for actuating said valve member between said closed and open positions while said armature is in said attracted position,

thermoelectric means adapted for energizing said electromagnet but insufiiciently to attract said armature from released position, resetting means operable for overcoming said biasing means and moving said electromagnet into engagement with said armature while overcoming said yieldable actuating means and holding said valve member in closed position, means effective upon completion of the resetting operation for retracting said electromagnet and causing movement of said armature out of operative engagement with said valve member to free the same for movement to open position by said actuating means.

3. A control device comprising in combination, a valve body having inlet and outlet passages for fluid and a valve seat, a valve member movable between open and closed positions relative to said seat for controlling fluid flow through said passages, a magnet housing carried by said body on one side of said seat, a movable electromagnet in said housing having an armature separable from said electromagnet for movement between attracted and released positions independently of said valve member, yieldable means operative between said electromagnet and said armature on one side of said seat for biasing said armature to released position to hold said valve member in closed position, yieldable actuating means operative from the opposite side of said seat for actuating said valve member between said closed and open positions while said armature is in said attracted position, thermoelectric means adapted for energizing said electromagnet but insufficient to attract said armature from released position, resetting means reciprocable relative to said housing for overcoming the first said yieldable means and moving said electromagnet into engagement with said armature while maintaining said armature in operative engagement with said valve member to overcome said actuating means and hold said valve member in said closed position, second yieldable means operative between said housing and said electromagnet for retracting the latter upon completion of the re-- setting operation and thereby causing movement of said armature out of operative engagement with'said valve member, and means operative from the opposite side of said seat for actuating said valve member to open position when the same is freed by said armature.

4. A control device comprising in combination, a valve body having inlet and outlet passages for fluid and a valve seat, a valve member a sesses movablesbetween openland closed positions 'relativeto saidseat forcontrollingfiuidflow through'. said passages-, a magnet housing-carried by said 11 body on one side: of -said seat and communicating 1 with. the interior of "said body, fiexible sealing means between said body and housing-for. closing.-said communicationtherebetween; said sealing means. being. movable independently of said r valve member and being biased away from said valve member, avmagnet cover mounted for slid-' ablermovement-in'said housing, an electromagnet carriedbv said cover for movement therewith" and whavin'gjsan armature iseparable from'isaid eleotromagnetpfora movement" between. attracted":

and released positions; an armature stem: projectingthrough said coverinto operative engage-- ment with said, sealingcmeans;firstspring means between: said; cover and projecting end of said sternfonbiasingtsaid armature to releasedposition' .andsaid sealing means into Operative-18ngagement with said valve member for holding,

thesame in closed position; thermoelectric means adapted for-energizing said electromagnet but insufliciently ;to attract saidarmature from re-' leased position, resetting; means reciprocable relative -to-said hOuSing and operable on said cover forovercoming said first springVmeans-and moving-said electromagnet into engagement with said armature, andsecond spring meansoperative'between said housing and said cover for retracting said 'electromagnet upon completion ofsaidqresetting. operation and thereby. causing.

movement of said sealin .meansout of operative engagement with said valve member;

5. A control device as claimed in claim having actuating means operative from the opposite sideof'said' seat from said first spring means for actuating said valve member to open position when the same is freed by said movement of said sealing .means, said actuating means inclu'dinga yieldable'connection adapted to be overcome by said resettingmeans duringsaid resettingiopera tio'n'l andlby said first spring means Whilev said armature isin said released position,

6."A'control device as claimed in claim 5.

wherein said actuating'means includes a thermostat and said yieldabl'e connectionincludes an override connection between said thermostat and said valve member, said override connection includingryi'eldable means incapable of resisting movement of, said valve member to closed-position uponmovement of said armature to released positionirrespective of thethermal condition of said thermostat.

7."'A contro1 device comprising in combination,-

a valvebody having inlet andloutletpassages for fluidsanda .valve seat; a valve member movable between open and closed positions-relative tosald seat for controlling' fluidi flow-through saidpassages;-a-magnet' housi-ngcarriediby said body on one side of said seat and communicating with the interior or said body, flexible-sealing-means between said body 'andsaid housing for closing said communication .tlierebetween, a magnet cover mounted ior 1 slidable' movementin said housing, an-electr'om'a'gnet-carriedby said cover for movement therewith and having an armature sep arable fr'om said ele'ctrom'agnettor movement be tween=attracted and released positions, anarma'- ture: stem-projecting through said cover for 'opE erative engagement with' said sealing means, first spring means between said cover and said projectingend-of said stem for'biasing said armature toreleased 'pos'ition and said sealing means into-operative" engagementwith said valve-member for holding the same in closed 1 position,- thermoelectriomeans adapted for energizing said'ele'ctro magnetbut insufliciently to attract said armature from said rele'asedposition, resetting means reciprocable'relative to said housing and operable on saidcover for overcoming said first spring means and moving-said electromagnet into engagement'with said armature, and second springm'eans'operative'between said housing and said cover 'for' retracting-said electromagnet upon completion of said resetting operation and thereby causing movement of said armature out of operative engagement with said 'valve 'memb'er.

8. Acontrol device-as claimed in claim '1 having yieldableactuating means operative-fromthe opposite side of said seat from'said first spring means for actuating said valve member to open position when'the-same is freed by said last named movement'of said armaturesaid' actuating'means'beingadapted to be overcome-bysaid resetting means during said resettingoperation :and by said first spring means-while said arma-- ture is in saidreleased position. 7

VVILBUR F. JACKSON;

REFERENCES 5 CITED' 'Ihefollowing references are of record-in the fileof this patent:

UNITED STATES PATENTS

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