US2578717A

US2578717A - Burner control mechanism

Info

Publication number: US2578717A
Application number: US163764A
Authority: US
Inventors: Charles M Mayer; John M Hoff
Original assignee: TAPPAN STOVE CO
Current assignee: TAPPAN STOVE Co
Priority date: 1950-05-23
Filing date: 1950-05-23
Publication date: 1951-12-18
Anticipated expiration: 1968-12-18

Description

Dec. 18, 1951 c. M. MAYER ET AL BURNER CONTROL MECHANISM 5 SheetsSheet 1 Filed May 23, 1950 INVENTORS (War/a9 M Mayer 9J0/1/7 Mf/off 3 Dec. 18, 1951 c. M. MAYER ET AL 2,573,717

BURNER CONTROL MECHANISM Filed May 25, 1950 Sheets-Sheet 2 I 5/ 69 .fZ 2'5 26 L Ml: i

6737 & v @8 9 1y? LF Char/es M Na er J 8 John N. Hog- 5 V464. H MZZZ/ IN V EN TORS Dec. 18, 1951 c. M. MAYER ET AL 2,573,717

BURNER CONTROL MECHANISM Filed May 25, 1950 5 Sheets-Sheet s 1951 c. M. MAYER ETAL BURNER CONTROL MECHANISM 5 Sheets-Sheet 4 Filed May 23, 1950 INVENTORS Char/es M Mayer 9 J0 m1 N. Hoff WW Dec. 18, 1951 c. M. MAYER ET AL 2,578,717

BURNER CONTROL MECHANISM Filed May 23, 1950 5 Sheets-Sheet 5 /94 /73 INVENTORS Char/es /7Z Mayer m5 m/ I Patented Dec. 18, 1951 BURNER CONTROL MECHANISM Charles M. Mayer and John M. Hofl', Mansfield, Ohio, assignors to The Tappan Stove Company, Mansfield, Ohio, a corporation of Ohio Application May 23, 1950, Serial No. 163,764

12 Claims.

1 This invention relates to automatic control mechanisms for cooking range burners using gaseous fuel, and is a modification of the invention disclosed in our co-pending application, Serial No. 153,664, filed April 3, 1950. It is especially designed and adapted for automatically controlling the operation of oven burners in cooking ranges which are equipped with a time control mechanism.

The mechanism is designed for use with a main gaseous fuel burner which is adapted to be ignited by a gaseous fuel pilot burner. In most cooking ranges in use today it is immaterial whether or not the oven burner burns constantly as long as the pilot burner associated therewith is ignited. It may be extinguished for some reason but it will be promptly re-ignited by the pilot burner if fuel is supplied thereto. But if the pilot burner is extinguished for any reason while the main control valve is still open to supply gas to the main burner a very dangerous situation sometimes arises. Let us assume that both the pilot burner and the main burner are extinguished during operation for some reason. Gas can then flow to the main burner but since the pilot burner is extinguished the main burner will not be ignited and unburned gas will accumulate in the oven which may violently explode when an attempt is made to ignite either the main or pilot burner. It has been found by experience that both the pilot burner and the main burner are frequently extinguished during use while the main control valve is open to supply gas to the main burner. It has also been found that a constantly burning pilot burner is frequently extinguished for some reason while the oven is not in use and the supply of gas to the main burner is cut off. This is sometimes due to a momentary failure of the gas supply or the slamming of the oven door or to various other reasons.

In order to prevent an accumulation of unburned gas and thus eliminate danger of an explosion therefrom in the event the pilot burner is extinguished for any reason while the control valve is still open to supply gas to the main burner, we provide in our improved apparatus safety control mechanism by which the, supply of gas to the main burner is cut off independently of the main control valve, in the event the pilot burner is extinguished for any reason while the main gas control valve is open.

One form of our improved apparatus as shown in Figs. 1 to 5 includes a main gaseous fuel burner by which the oven in a cooking range is heated. The main burner is adapted to be ignited by a the pilot burner.

2 gaseous fuel pilot burner which burns only during the time the oven is in operation. At other times the supply of gas to both the main burner and the pilot burner is cut oil by a main control valve which is interposed in a conduit between the gas supply manifold and the burners. When the main control valve is open gas will flow from the main control valve and into a safety control valve mechanism. From the safety control valve mechanism gas will flow through a small branch conduit directl to the pilot burner; and through the main conduit and a standard thermostatically operated oven temperature control valve to the main burner. A normally open master control switch which is operatively associated with the main control valve is arranged to be closed by the opening of the main control valve and to be opened by the closing of the main control valve. The closing of the master control switch, as the main control valve is opened to supply gas to the burners, energizes through a. normally closed thermostatically operated switch an electric resistance ignition element and a solenoid which is operatively connected to the safety control valve mechanism. The energization of the solenoid causes it to operate the safety control valve mechanism to permit the flow of gas to the pilot burner while cutting off the supply of gas to the main burner. The pilot burner is then ignited by the electric ignition element and projects a flame against a thermostatic element, which controls the operation of the normally closed switch, and against a thermo couple which is operatively connected to the safety control valve mechanism. After the thermostatic element becomes heated it opens the normally closed switch which deenergizes the electric ignition element and the solenoid. As soon as the solenoid is de-energized the safety control mechanism is automatically operated by spring means to supply gas to the main burner through the oven temperature control valve. The main burner is then ignited by The thermocouple, as long as it is heated by the pilot burner, maintains the safety control valve mechanism in condition to supply gas to both the main burner and the pilot burner. The oven temperature control valve then regulates the supply of gas to the main burner so as to maintain the desired oven temperature. As lOI'lg as the pilot burner is ignited the main burner will burn normally under the control of the oven temperature control valve until the main control valve is manually turned 011'. But if during operation the pilot burner is extinguished for any reason the thermocouple will immediately cool and allow the safety control valve mechanism to automatically cut off the supply of gas to both the .main burner and the pilot burner. As an example of the manner of operation of the apparatus, let us assume that during operation the pilot burner is suddenly extinguished, for instance, by a, momentary failure of the gas supply from the manifold to the burners. The thermocouple immediately cools, allowing the safety control valve mechanism to cut off communication between the manifold and both the main burner and the pilot burner. The main control valve is still open and the master switch closed. Then after the thermostatic element has cooled, closing the normally closed switch, which is maintained open by the thermostatic element during normal operation of the oven, the electric ignition element and the solenoid are again energized. The energization of the solenoid will cause it to operate the safety control valve mechanism to reestablish communication between the manifold and the pilot burner only. Then when gas is again available the pilot burner will be ignited and reestablish normal operation of the oven as previously described. In the event of a power failure during normal operation of the oven, the main burner will continue to operate normally under the control of the oven temperature regulator valve until the burner is turned off by the main control valve, assuming of course that the pilot burner continues to burn. In the event of a power failure before gas is turned on by the main control valve, the pilot burner can be manually ignited as will be hereinafter explained. The supply of gas to both the main burner and the pilot burner will then be controlled by the pilot burner through the thermocouple and safety control valve mechanism as previously described.

In order to accommodate the apparatus for use in conjunction with any standard type time control mechanism, we provide a supplemental master switch and a normally open solenoid valve. The supplemental master switch is inserted in the main circuit in series with the primary master switch and is adapted to be closed at a predetermined time by the time control mechanism. The normally open solenoid valve is inserted in the branch conduit between the safety control valve mechanism and the pilot burner, and is adapted to be closed at a predetermined set time by the time control mechanism. In use the time control mechanism is set to initiate operation of the oven burner at a predetermined time and to terminate operation thereof at a predetermined later time, after the main control valve hasbeen turned on which also closes the primary master switch. Then when the supplemental switch which is in series with the primary switch is closed by the time control mechanism the apparatus will function in the same manner as previously described, until the time control mechanism effects the closing of the normally open solenoid valve which cuts off the supply of gas to and extinguishes the pilot burner which in turn causes the safety control valve mechanism to operate to cut off the supply of gas to and thus extinguish the main burner. Means to lock the supplemental switch closed is provided in order that the apparatus may be used independently of the time control mechanism when desired.

Another form of our invention (Figs. 6 to 10) includes a main gaseous fuel oven burner which is adapted to be ignited by a constantly burning pilot burner which is associated therewith. The

supply of gas to the main burner is controlled by a main control valve which is interposed in a conduit between the gas supply manifold and the main burner. When the main control valve is open gas flows from the manifold through the main control valve and into a safety control valve mechanism. From the safety control valve mechanism the gas flows through a standard thermostatically operated oven temperature control valve to the main burner where it is ignited by the pilot burner. Gas is constantly supplied to the pilot burner through a secondary conduit which extends between the manifold and the pilot burner. The pilot burner projects a flame against a thermocouple which is operatively connected to the safety control valve mechanism. As long as the thermocouple is heated by the pilot burner it will energize an electro-magnet which when energized will maintain the safety control valve mechanism in condition to supply gas to the main burner. The oven temperature control valve then regulates the gas flowing from the safety control valve mechanism in order to maintain the desired oven temperature. If during operation the pilot burner is extinguished for any reason the thermocouple will immediately cool which will de-energize thev electro-magnet and cause the safety control valve mechanism to cut off the supply of gas to the main burner. The pilot burner must then be manually lighted and after the thermocouple has become heated by the pilot burner the safety control valve mechanism must be manually reset in condition to again supply gas to the main burner. The electro-ma net which is energized by the thermocouple is strong enough to maintain the safety control valve mechanism in set position, but is not strong enough to reset it. Consequently it must be reset manually. After resetting the apparatus will function normally as described as long as the pilot burner is ignited. If during use the main burner is extinguished for any reason it will be immediately reignited by the pilot burner.

In order to accommodate this form of the invention for use. with a standard time control mechanism, we provide an interrupter switch in the circuit between the thermocouple and the electro-magnet. We also provide a solenoid which is operative to automatically reset the safety control valve mechanism after the electro-magnet has been de-energized by the momentary opening and closing of the interrupter switch. When used the time control mechanism is first set to initiate operating of the oven main burner at a predetermined time and to terminate operation thereof at a predetermined later time, and then the main control valve is opened. The setting of the time control mechanism momentarily opens and then clos s the interrupter switch in the circuit between he thermocouple and the electro-magnet. The momentary opening of the interrupter switch momentarily de-energizes the electro-magnet which causes the safety control valve mechanism to cut off the supply of gas to the main burner. The safety control valve mechanism will remain in this condition until it is reset by the solenoid which is provided for this purpose. At the predetermined set time to initiate operation of the main burner the time control mechanism through a suitable switch will momentarily energize the solenoid which will automatically reset the safety control valve mechanism to supply gas to the main burner where it will be ignited by the constantly burning pilot burner. At the predetermined set later time for terminatingoperation of the oven burner the time control -mechani$m' will momentarily open the interrupter switch and de-energire the electro-magnet which will cause the safety control valve mechanism to cut off the supply of gas to the oven burner and terminate operation thereof. When the time control mechanism is not used the interrupter switch is locked in closed position.

The principal object of the invention is to provide an improved automatic control system for cooking range oven burners using gaseous fuel.

Another object of the invention is to provide in an electrical ignition and control system of the character described improved means for completely shutting off the supply of gas to both the main burner and the pilot burner in the event the pilot burner becomes extinguished for any reason before the supply of gas to both the main burner and the pilot burner is cut oil by the main control valve.

Another object of the invention is to provide an improved automatic control mechanism for a cooking range which is equipped with a constantly burning pilot burner from which the main.

oven burner is ignited.

Still another object of the invention is to provide an improved control system of the character described which may be used in conjunction with a time control mechanism or independently thereof as desired.

Other and more limited objects of the invention will be apparent from the following specification and the accompanying drawing forming a part thereof, wherein:

Fig. 1 is a diagrammatic view illustrating one form of our improved control mechanism as applied to a cooking range oven burner using aseous fuel;

Fig. 2 is an enlarged central longitudinal vertical section through the safety control valve mechanism of Fig. 1 showing the various parts in the position they assume when the oven burner is turned off;

Fig. 3 is a view similar to Fig. 2 showing the various parts in the positions they are automatically moved to when the main control valve is first turned on to initiate the operation of the main oven burner;

Fig. 4 is a horizontal section taken on the line 4-4 of Fig. 1;

Fig. 5 is a wiring diagram of this form of the apparatus as used in conjunction with a time control mechanism.

Fig. 6 is a view similar to Fig. 1 showing another form of the invention;

Fig. 7 is an enlarged central longitud nal vertical section through the safety control valve mechanism of Fig. 6 showing the various parts in position to cut off the supply of gas to the main burner;

Fig. 8 is a view similar to Fig. 7 showing the various parts in position to supply gas to the main burner;

Fig. 9 is a horizontal section taken on the line 99 of Fig. 6; and I Fig. 10 is a wiring diagram illustrating the use of the apparatus of Fig. 6 in connection with a time control. mechanism.

Referring now to Figs. 1 to 5 of the drawings by reference characters, the numeral I indicates a gaseous fuel burner which is mounted in or in heating relation to a cooking range oven 2. Gaseous fuel is supplied to the burner I from a manifold M through a conduit 3. Interposed in the valve 6.

conduit 3 are a main control valve 4, a safety control valve mechanism generally indicated by the numeral 5, and an oventemperature control The main control valve 4 is a cut-off valve of standard construction which when in open or on position permits the flow of gas through the conduit 3 from the manifold to the burner I, and in closed or olf position cuts 011' flow of gas to the burner I. This valve is manually opened and closed by a handle I and a valve stem 8, anddirectly controls the operation of the entire apparatus in that it initiates the operation of the entire apparatus when it is turned to the on position and terminates the operation when it is turned to the off position. From the main control valve 4 gas flows through a connector 9 to the safety control valve mechanism 5, to be described in detail hereinafter. From the safety control valve mechanism 5 the gas flows through a connector [0, the oventemperature control valve 6 and the conduit 3 to the burner I. The oven temperature control valve 6 is operative to regulate the amount of gas flowin to the burner I in order to maintain the oven at any desired set temperature. The valve 6 is set to any desired temperature by a handle II having a pointer I2 which cooperates with a graduated dial I3 carried by the valve 6. The valve 6 is controlled according to the temperature setting by a thermostatic element I4 which is mounted in the oven 2 and is connected to the valve 6 as shown at l5. The oven temperature control valve 6 is of standard well known construction. quently it is not shown in detail herein. There are many different constructions available any one of which will work equally well herein. Gas is also supplied to a pilot burner I6 through a branch conduit I! which extends between the safety control valve mechanism and the pilot burner I6. A normally open valve V which is adapted to be closed by a solenoid S is interposed in the branch conduit II between the safety control valve mechanism 5 and the pilot burner I6 for a purpose to be hereinafter described. The pilot burner I6 is disposed adjacent the rear end of the main burner I in position to ignite the burner I when gas is supplied thereto. An electrical ignition element I8 is operatively associated with the pilot burner I6 in position to ignite the pilot burner I6 when gas is supplied thereto. A thermostatic element I 9 and a thermocouple 20 are mounted in position to be heated by a flame from the pilot burner. The thermostatic element I9 is operative to open and close a switch II which controls the energization of the electrical ignition element I8 and a solenoid 22 which when energized operates the safety control valve mechanism to supply gas to the pilot burner I6 as will be described in connection with the description of the safety control valve mechanism and the operation of the whole apparatus. The thermocouple 20 when heated is operative to hold the safety control valve mechanism in condition to maintain the supply of gas to both the pilot burner I6 and the main burner I, as will also be described in connection with the description of the safety control valve mechanism and the operation of the apparatus. A master switch 23 which is associated with the main control valve 4 is adapted to be opened and closed simultaneously with the closing and openin of the main control valve 4. As the control valve 4 is turned from the off or closed position to the on or opened position the switch 23 is moved from the open position to the closed position by an operating Conselever 24 which cooperates with a cam section 25 on the main control valve stem 8. Conversely, when the main control valve 4 is turned from the open or on position to the closed or oil position the switch 23 is moved from the closed position to the open position. An electric circuit between the thermocouple 26 and the safety control valve mechanism is established by a copper tube 26 which encloses an insulated wire 21.

The construction of the safety control valve mechanism 5 and its connection to the solenoid 22 will now be described, reference being had to Figs. 2, 3 and 4 of the drawing. This mechanism comprises a casing 35 having a chamber 36 in one end thereof and a chamber 31 in the other end thereof. The chambers 36 and 31 are connected by a bore 38 of reduced diameter. A valve seat 39 is located at one end of the bore 38 and a similar valve seat 46 is located at the other end of the bore 38. The chamber 36 is closed by a removable cap 4| and the chamber 31 is closed by a removable cap 42. A sleeve 43, having

end walls

44 and 45, is carried by the cap 4| and extends into the chamber 36. A valve stem 46 which is slidably mounted in a bushing 41 carried by the end wall 45 of the sleeve 43, extends from the chamber 36 into the sleeve 43. A valve disc 48 of suitable material is secured to one end of the valve stem 46 within the chamber 36, and a metal disc 49 is secured to the other end of the stem 46 within the sleeve 43. A spring 56 disposed about the valve stem 46 between the valve disc 48 and the end wall 45 of the sleeve 43 normally holds the valve disc 48 against the valve seat 39. An electro-magnet 5| is secured to one end of a hollow exteriorly threaded stud 52 which extends out through aligned apertures in the end wall 44, of the sleeve 43, and in the end of the cap 4|. A nut 53 screwed onto the outer portion of the stud 52 securely holds the magnet 5| and the sleeve 43 in place. The legs of the magnet 5| have a winding 54 thereon one end of which is connected to the tube 26 and the other end of which is connected to the wire 21 in the tube 26. The tube 26 is inserted into the hollow stud 52 and is held in place by a screw fitting 28. A sleeve 55 is screwed into a threaded recess in the end of the cap 42, as indicated at 56, and extends into the chamber 31 a slight distance. One end of the sleeve 55 is closed by an end wall 51, and the other end which is open registers with a circular aperture 58 in the end wall of the cap 42. A plug 59 is slidably mounted in the sleeve 55 and extends out through the aperture 58 in the cap 42. The outer end of the plug 59 has a reduced extension 66 formed integral therewith, providing an annular shoulder 8| around the extension 66 at the outer end of the plug 59. A stem 62 which is secured to the inner end of the plug 59 extends out through an aperture 63, in the end wall 51 of the sleeve 55, and through the chamber 31 and into the bore 38. The stem 62 has a. collar 64 rigidly secured thereon between the end wall 51 and the outer end of the stem. A valve disc 65 of suitable material is slidably mounted upon the stem 62 between the end wall 51 of the sleeve 55 and the collar 64. The valve disc 65 is adapted to engage the valve seat 46 to cut off the flow of gas into the chamber 31 during the initiation of operation as will be hereinafter described. A compression spring 66 disposed about the stem 62 between the end wall 51 and the valve disc 65 normally yield'ingly holds the valve disc 65 against the collar 64. A compression spring 61 which is stronger than the 8 spring 66 is disposed about the stem 62 within the sleeve 56 between the inner face of the end wall 51 and the inner end of the plug 59. The spring 61 is operative to return the plug 59, stem 62 and valve disc 65 from the position shown in Fig. 3 back to their normal position as shown in Fig. 2, against the resistance of the' spring 66. A port 68 in the casing 35 provides communication between the chamber 36 and the connector 9 to allow gas to flow from the main control valve 4 through the connector 9 and into the chamber 36. During normal operation of the main burner gas flows from the chamber 36 through the reduced intermediate bore 38 and into the chamber 31. A port 69 which establishes communication between the conduit l1 and the bore 38 is provided to supply gas to the the pilot burner I6; and a port 16 establishes communication between the chamber 31 and the connector l6 to permit the fiow of gas from the chamber 31 to the main burner I through the oven temperature control valve 6 and the conduit 3.

The safety control valve mechanism 5 is operatively connected to the solenoid 22 by a yoke 12 and a link 13. The yoke 12 which encompasses the safety control valve mechanism 5 as shown in Fig. 4 comprises a pair of spaced parallel arms 14 which are connected together at one end by a bridge 15. The bridge 15 has an aperture 16 therein through which the reduced end 66 of the plug 59 extends with the inner face of the bridge engaging the shoulder 6| between the plug 59 and the reduced extension 66 thereof. The other ends of the arms 14 terminate in a pair of spaced parallel ears 11 to and between which one end of the link 13 is pivotally connected. The other end of the link 13 is pivotally connected to the movable core 18 of the solenoid 22 as indicated at 19.

The master control switch 23 comprises the

contacts

82 and 83 which are adapted to be bridged by the conductor bar 84; and the switch 2| comprises three

contacts

86, 89 and 96 which are adapted to be bridged by a conductor bar 9| when the switch is in its normal closed position.

The supplemental master switch 92 which is shown in Fig. 6 comprises the

contacts

93 and 94 which are adapted to be bridged by a conductor bar 95; and a switch 96 which is shown in Fig. 6 comprises the

contacts

91 and 98 which are adapted to be bridged by a conductor bar 99. The contact 91 of the switch 96 is connected to the side |65 of the line by a lead 86, and the contact 98 of the switch 96 is connected to one end of the winding 8| of the solenoid S by a lead 85. The other end of the winding 8| of the solenoid S is connected to the other side I69 of the line by a lead 86. The switch 96 thus controls the energization of the solenoid S which when energized closes the normally open valve V. The conductor bars 95 and 99 are mounted on a base I66. of insulating material, which is adapted to be moved toward and away from the

contacts

93, 94, 91 and 98 at predetermined times by a time control mechanism |6| through a connecting link I62. When it is desired to operate the oven burner independently of the time control mechanism, the switch 92 is locked in closed position and the switch 96 is locked in open position through the medium of a manually operable button I63 incorporated in the time control mechanism |6|.

The operation of the apparatus independently of the time control mechanism will now be de-.

scribed in connection with Fig. 5. To initiate the operation of the oven burner I it is only necessary to set the oven temperature control valve 6 to the desired temperature and to manually turn the main control valve 4 from the off position to the on position. After that the ignition and operation of the burner are automatically controlled until the operation of the burner is terminated by manually turning the main control valve 4 from the on position to the off position. As the main control valve 4 is turned from the off position to the on position the masterl switch '23 is closed by the cam 25 and lever 24. After the main control valve has been opened gas can fiow from the manifold M through the main control valve 4 and into the chamber 36 of the safety control valve mechanism 5, the various parts of which are in the position shown in Fig. 2. But the gas can go no farther since the valve disc 48 is being held against the valve seat 39 by the spring 58, thus closing the only exit from the chamber 36. As soon as the switch 23 is closed current flows from one side I85 of the line through-the lead I06 to the terminal 82 and thence through the conductor bar 84 to the terminal 83. From the terminal 83 the current flows through the lead I01 and the switch 92 which is locked in closed position to the terminal 88 of the normally closed switch 2|, and thence through the conductor bar 9I to the

terminals

89 and 98. From the terminal 89 the current flows through the lead I08 to the electrical resistance ignition element I8, thence through the ignition element I8 and back to the other side I89 of the line through the lead IIIJ, thus completing a circuit through the ignition element I8 which energizes it and renders it operable to ignite the pilot burner I6 as soon as gas is supplied thereto. From the terminal 90 of the normally closed switch 2| the current flows through the lead III to the solenoid 22, thence through the winding of the solenoid and back to the other side I99 of the line through the lead II2, thus completing a circuit which energizes the solenoid 22. The energization of the solenoid 22 causes it, through the link 13 and yoke I2, to shift the various parts of the safety control valve mechanism from the position shown in Fig. 2 to the position shown in Fig. 3. In this position the valve disc 48 is held away from the valve seat 39 and the metal disc 49 is held against the ends of the legs of the magnet 5I by the stem 62 acting against the resistance of the spring 58. This allows gas to flow from the chamber 36 into the bore 38 and thence through the port 69 and conduit II to the pilot burner I6 where it is ignited by the ignition element I8. But the gas cannot yet fiow to the main burner I since the valve disc 65 is being held against the seat 40 by the spring 66 which cuts off communication between the bore 38 and the chamber 31. As soon as the pilot burner I6 is ignited it projects a flame against and heats both the thermocouple 20 and the thermostatic element I9. The heating of the thermocouple 20 generates a minute current which energizes the electro-magnet 5I sufiiciently for it to hold the metal disc 49 and the stem 46 and valve disc 48 secured thereto in the position shown in Fig. 3 against the pressure of the spring 50 after the disc 49 has been moved into engagement with the magnet 5| by the solenoid 22. But the magnet 5| when energized by the thermocouple 20 is not strong enough to attract and withdraw the metal disc 49, and the stem 46 and valve disc 48 secured thereto, from the position shown in Fig. 2 to the position shown in Fig. 3. It can only hold these parts in this position after they have been moved thereto by the-solenoid 22 through the medium of the link 13, yoke I2, plunger 59 and stem 62. The electric circuit between the thermocouple 20 and the winding 58 of the magnet 5| is through the copper tube 26 and the wire 21. This circuit will be maintained as long as the thermocouple is heated. After the thermostatic element I9 has been heated sufiiciently, which is after the thermocouple has energized the magnet 5|, it will open the normally closed switch 2I, breaking the circuit to and de-energizing both the ignition element I8 and the solenoid 22. After the pilot burner has been ignited there is no further need to maintain the ignition element energized. As soon as the solenoid 22 is de-energized the spring 61 will return the plunger 59, stem 62 and valve disc 65 back from the position shown in Fig. 3 to the position shown in Fig. 2 against the pressure of the spring 66. The valve disc 48will be held in the position shown in Fig. 3 by the magnet 5I. Communication is then established between the chambers 36 and 31 through the bore 38. Gas will then fiow from the chamber 36 into the chamber 31 through the bore 38. From the chamber 31 gas will flow through the oven temperature control valve 6 and conduit 3 to the main burner I where it will be ignited by the pilot burner I6. The apparatus is now operating normally, and in the absence of any abnormal conditions it will continue to do so, provided the pilot burner remains ignited, until the supply of gas to both the pilot burner and the main burner is cut 01? by the manual closing of the main control valve 4.

In the event the pilot burner I6 is extinguished for any reason during operation, the thermocouple 20 will cool in a few seconds and deenergize the magnet 5|. The de-energizing of the magnet 5| will allow the spring 58 to move the valve disc 48 back into engagement with the valve seat 39, as shown in Fig. 2, which will cut off the flow of gas from the chamber 36 into the bore 38 and chamber 31, and from them to the pilot light I6 and the main burner I. The burner I will then be extinguished along with the pilot burner. As son as the thermostatic element I9 cools it will close the switch 2I which will energize both the ignition element I 8 and the solenoid 22 as previously described since the main control valve 4 is still open and the switch 23 is closed. The pilot burner I6 will then be re-ignited and the rest of the apparatus will again function as described, provided there is gas available. If no gas is available every hing will remain in condition to ignite the pilot burner and re-initiate operation as soon as gas is again available. In the event of either a momentary or prolonged power failure during operation, the apparatus will continue to operate normally until terminated by the manual closing of the main control valve, provided of course that all other conditions are normal. In order to operate the apparatus during a prolonged power failure tinue to function normally as described under the control of the pilot burner I6 and the oven temperature control valve 6.

When the apparatus is used in conjunction with the time control mechanism IOI the time control mechanism is set to initiate operation of the main burner I at a predetermined time and to terminate operation thereof at a predetermined later time. The setting of the time control mechanism IOI opens the

switches

92 and 96 as shown in Fig. 5. Qperating current is supplied to the time control mechanism from the line I-I09 by the leads H1 and H8. After the time control mechanism has been set the main control valve 4 is manually opened which closes the master switch 23. Then at the predetermined set time the time control mechanism will close the supplemental switch 92 and es- A tablish the circuits to the ignition element I8 and the solnoid 22. The apparatus will then operate as previously described until the time control mechanism terminates operation by closing the switch 96. The closing of the switch 96 energizes the solenoid S which then closes the valve V. The closing of the valve V cuts off the supply of gas to and extinguishes the pilot burner I6. After the pilot burner I6 has been extinguished the thermocouple cools which de-energizes the electro-magnet 5|. The safety control valve mechanism will then operate as previously described to cut off the supply of gas to the main burner, thus terminating the operation thereof. The main control valve 4 can then be manually closed at any time.

Referring now to Figs. 6 to 10, inclusive, of the drawing wherein a gaseous fuel burner I2I is shown in an oven I22. Fuel is supplied to the burner I2I from the manifold M by a conduit I23. Interposed in the conduit I23 between the manifold M and the main burner I2I are a main control valve I24, a safety control valve mechanism I25 and an oven temperature control valve I26. The main control valve I24 is a cut-off valve of standard construction which when in open or on position permits the flow of gas from the manifold M to the main burner I2I and when in closed or off position cuts off the flow of gas thereto. This valve is manually opened and closed by a handle I21 secured to the valve stem I28, and primarily controls the operation of the main burner in that it must be turned on to initiate operation of the burner and when it is turned off the burner cannot function. From the main control valve I24 gas flows through a connector I29 to the safety control valve mechanism I25, to be described in detail hereinafter. From the safety control valve mechanism I25 the gas flows through a connector I30 to the oven temperature control valve I26 and from there to the main burner I2I. The oven temperature control valve I26 is operative to regulate the amount of gas flowing to the burner I2I in order to maintain the oven at any desired set temperature. The'valve I26 is set to maintain any desired temperature by a handle I3I having a pointer I32 which cooperates with a graduated dial I33 carried by the valve I26. The valve I26 is controlled according to the temperature setting by a thermostatic element I34 which is mounted in the oven I22 and is connected to the valve I26 as indicated at I35. The oven temperature control valve I22 is of standard well known construction. Consequently it is not shown and described in detail herein. There are many different types, any one of which will operate equally well herein. Gas is supplied to a constantly burning pilot burner I36 through a small secondary conduit I31 which connects the pilot burner I36 directly to the manifold M. A cutoff valve I38 by which the supply of gas to the pilot burner I36 may be manually cut off if desired is interposed in the conduit I31. The pilot burner I36 is mounted adjacent the rear end of the main burner I2I in position to ignite the main burner I2I whenever gas is supplied thereto. A thermocouple I40 is disposed adjacent the pilot burner I36 in position to be heated by a flame therefrom. The thermocouple I40 is connected to the safety control valve mechanism I35 and is operative when heated to maintain the safety control valve mechanism in condition to supply gas to the main burner I2I when the main control valve is open as will be described in connection with the description of the safety control valve mechanism and the operation of the apparatus. An electric circuit is established between the thermocouple I40 and the safety control valve mechanism by a copper tube I46 which encloses an insulated wire I41. The wire I41 is severed between the thermocouple I40 and the safety control valve mechanism I25 and an interrupter I48 having terminals I49 and I50 is interposed between the severed ends. One of the severed ends of the wire I41 is connected to the terminal I49 and the other severed end is connected to the terminal I50. The purpose and function of the interrupter I48 will be explained in detail in connection with the description of the operation of the apparatus.

The construction of the safety control valve mechanism I25 will now be described, reference being had to Figs. '7, 8 and 9 of the drawings. This mechanism comprises a casing I55 having a chamber I56 in oneend thereof and a chamber I51 in the other end thereof, which are connected by a bore I58 of reduced diameter. A valve seat I59 is loiated at one end of the bore I58 within tne chamber I56 which is closed by a removable cap I6I. A cylindrical sleeve I63, having end walls I64 and I65, is carried by the cap I6I and extends into the chamber I56. A valve stem I66 which is slidably mounted in a bushing I61 carried by the end wall I65 of the sleeve I63, extends from the chamber I56 into the sleeve I63. A valve disc I68 of suitable material is secured to one end of the valve stem I66 within the chamber I56, and a. metal disc I69 is secured to the'other end of the valve stem I66 within the sleeve I63. A spring I10 disposed about the valve stem I66 between the valve disc I68 and the end wall I65 of the sleeve I63 normally holds the valve disc I68 against the valve seat I59. An electromagnet I1I is secured to one end of a hollow exteriorly threaded stud I12 which extends out through aligned apertures in the end wall I64 of the sleeve I63, and in the end of the cap I6I. A nut I13 screwed onto the outer portion of the stud I12 securely holds the electro-magnet HI and the sleeve I63 in place. The legs of the electro-magnet I1I have a winding I14 thereon one end of which is connected to the tube I46 and the other end of which is connected to the wire I41 in the tube I46. The tube I46 is inserted into the hollow stud I12 and is held in place by a screw fitting I48. A sleeve I15 which is carried by the cap I62 as indicated at I16 extends through the chamber I51 and into the bore I58 a short distance. One end of the sleeve I15 is closed by an end wall I11, and the other end which is open registers with a circular aperture I18 in the end wall of the cap I62. A plug I19 is slidably mounted in the sleeve I15 and extends out through t e aperture I18 in the cap I52. The outer end of the plug I19 has a reduced extension I88 formed integral therewith, providing an annular shoulder I8I around the extension I88 at the outer end of the plug I19. A stem I82 which is secured to the inner end of the plug I19 extends out through an aperture I83 in the end wall I11 of the sleeve I15 and into the bore I58. A compression spring I81 which is disposed about the stem I82 within the sleeve I15 between the inn r face of the end wall I11 and the inner end of the plug I19 is operative to return the plug I19 and stem I82 from the position shown in Fig. 8 back to their normal position as shown in Fig. '1. A port I88 in the casing I55 provides communication between the chamber I56 and the connector I29, and a port I98 establishes communication between the bore I58 and the connector I38. During normal operation gas flows from the main control valve I24 through the connector I29 and port I88 into the chamber I56 and bore I58. From the bore I58 the gas flows through the port I98 and connector I38 into the oven temperature control valve I26 and from there to the main burner I2I.

The plug I19 of the safety control valve mechanism is operatively connected to a solenoid I42 by a yoke I92 and a link I93. The yoke I92 which encompasses the safety control valve mechanism I25 as shown in Fig. 9 comprises a pair of spaced parallel arms I94 which are connected together at one end by a bridge I95. The bridge I95 has an aperture I96 therein through which the reduced end I88 of the plug I19 extends with the inner face of the bridge engaging the shoulder I8I between the plug I19 and the reduced extension I88 thereof. The other ends of the arms I94 terminate in a pair of spaced parallel ears I91 to and between which one end of the link I93 is pivotally connected. The other end of the link I93 is pivotally connected to the movable core I98 of the solenoid I42 as indicated at I99.

The solenoid I42 and the interrupter I48 are provided to adapt the apparatus for use in conjunction with a standard time control mechanism 288. When the apparatus is used independently of a time control mechanism the solenoid I42 and the interrupter I48 have no function. When the solenoid I42 is energized it is operative to shift the valve I68 of the safety control mechanism I25 from the closed position as shown in Fig. '1 to the open position as shown in. Fig. 8. The energization of the solenoid I42 is controlled by a switch 28I which is adapted to be opened and closed at predetermined set times by the time control mechanism 288. The switch 28I comprises a pair of contacts 282 and 283 which are adapted to be bridged by a conductor bar 284 which is connected to the time control mechanism 288 as indicated at 285. The contact 282 is connected to one side 288 of the line by a lead 281, and the contact 283 is connected to one end of the winding of the solenoid I42 by a lead 288. The other end of the winding of the solenoid I42 is connected to the other side 289 of the line by a lead 2I'8.

The terminal I49of the interrupter I48 is connected to the contacts 2 and 2I2 of a double pole switch 2I3 by a lead 2I4, and the terminal I58 of the interrupter I48 is connected to the contacts 2I5 and 2I6 of the switch 2I8 by a lead 2I1. The contacts 2H and 2I5 and the contacts 2 I 2 and 2 I 6 are adapted to be alternately bridged by a conductor bar 2| 8 which is shifted from one position to the other at predetermined set times by the time control mechanism through a connection 2I9.

When this form of the apparatus is used independently of the time control mechanism 288 the switch 2I3 is in the position shown in Fig. 10 with the conductor bar 2I8 bridging the contacts 2I I and 2 I5. Theoperation of the main burner I2I is then manually initiated and terminated by the main control valve I24. When the main control valve is turned to the on position gas flows from the manifold M through the main control valve I24, safety control valve mechanism I25 and oven temperature control valve I26 to the main burner I2I where it is ignited by the constantly burning pilot burner I36. After the burner I2I has been ignited the supply of gas thereto is controlled by the oven temperature control valve in accordance with the setting thereof. Should the constantly burning pilot burner I36 become extinguished for any reason while the main burner I2I is ignited, the thermocouple I48 will cool which will de-energize the electro-magnet I 1|, after which the spring I18 will shift the valve disc I68 into engagement with the valve seat I59 and cut off the flow of gas from the safety control valve mechanism I25 to the main burner I2I through the oven tempera ture control valve I26. he main burner I2I cannot be ignited/again until after the pilot burner I36 has been manually ignited and the safety control valve mechanism manually reset which cannot be done until after the thermocouple has been heated by the pilot burner. The safety pontrol valve mechanism I25 is reset by manually depressing the plug I19 from the position shown in Fig. '1 to the position shown in Fig. 8 which moves the valve disc I68 from the seat I59 and reestablishes communication between the main control valve I24 and the main burner IN. The electro-magnet III then holds the valve disc I68 in set position. The electro-magnet I1I as previously stated when energized is strong enough to hold the valve disc I68 in set position against the pressure of the spring I18 as shown in Fig. 8,

but it is not strong enough to shift the disc I68 from the position shown in Fig. 7 to the position shown in Fig. 8. It must be shifted by other means.

When the apparatus is used in conjunction with the time control mechanism 288, the time control mechanism is first set to initiate operation at a predetermined time and to terminate operation at a pretermined later time. The setting of the time control mechanism 288 shifts the conductor bar 2 I 8 of the switch 2 I3 from engagement with the contacts 2 and 2I5 and into engage ment with the contacts 2 I2 and 2 I6. The shifting of the conductor bar 2 I8 momentarily breaks the electric circuit between the thermocouple I48 and the electro-magnet I1I which de-energizes the electro-magnet HI and causes it to release the valve disc I68 which is then moved by the spring I18 from the position shown in Fig. 8 to the position shown in Fig. 7, thus closing the exit from the chamber I56 and preventing gas from flowing from the safety control valve mechanism I25 to the main burner I2 I. When the conductor bar 2I8 engages the contacts M2 and 2I8 the time to initiate operation the time control mechanism 200 will momentarily close the switch 20I by moving the conductor bar 2M into and then out of engagement with the

contacts

202 and 203. The closing of the switch 20I energizes the solenoid I42 which then resets the safety control valve mechanism, as shown in Fig. 8, to supply gas to the main burner I2I where it is ignited by the constantly burning pilot burner I36. The main burner then operates under the control of the oven temperature control valve until it is extinguished by the time control mechanism. At the set time for terminating operation the time control mechanism 200 moves the conductor bar 2 I8 of the switch 2I3 out of engagement with the contacts 2I2 and 2I6 and back into engagement with the contacts 2H and 2I5. Theshifting of the conductor bar 2I8 momentarily breaks the electric circuit between the thermocouple M and the electro-magnet III which de-energizes the electro-magnet I.'I and causes the safety control valve mechanism I25 to cut off the supply of gas to and extinguish the main burner I2I as previously described. The main control valve I24 can then be turned off at any time. In the event the constantly burning pilot burner I36 is extinguished for any reason during automatic operation the safety control valve mechanism I25 will function as described in connection with the manual operation of the apparatus.

From the foregoing it will be apparent to those skilled in this art that we have provided a very simple and efficient means for accomplishing the objects of our invention; and it is to be understood that we are not limited to the specific constructions shown and described herein as various modifications may be made thereto within the scope of the appended claims.

What is claimed is:

1. In a burner control apparatus of the character described, the combination of a main burner, a pilot burner by which said main burner is ignited, a conduit through which gaseous fuel is supplied to said main burner, a safety control valve mechanism operative to control the supply of fuel to said main burner interposed in said conduit, a solenoid and operative connecnections between said solenoid and said safety control valve mechanism, a thermocouple disposed adjacent said pilot burner in position to be heated thereby and operative connections between said thermocouple and said safety control valve mechanism, said solenoid being operative when energized to set said safety control valve mechanism in condition to supply fuel to said main burner and said thermccouple being operative when heated to maintain said safety control valve mechanism in said set condition, means operable to control the energization of said solenoid, means operable to render said thermocouple ineffective to maintain said safety control valve mechanism in said set condition, a time control mechanism, operative connections between said time control mechanism and said first mentioned means by which said first mentioned means is a.tuated at a predetermined time by said time control mechanism to energize said solenoid, and operative connections between said time control mechanism and said second mentioned means by which said second mentioned means is actuated by said time control mechanism at a predetermined later time.

2. In a burner control apparatrs of the character described, the combination of a main burner, a pilot burner by which said main burner is ergized to set said safety control valve-mechanism in condition to supply fuel to said main burner, said electro-magnet being operative when energized to maintain said safety control valve mechanism in said set condition and said thermocouple being operative to energize said electromagnet, means operable to control the energization of said solenoid, means operable to render said thermocouple ineffective to energize said electro-magnet, a time control mechanism, operative connections between said time control mechanism and said first mentioned means by which said first mentioned means is actuated at a predetermined time by said time control mechanism to energize said solenoid. and operative connections between said time control mechanism and said second mentioned means by which said second mentioned means is actuated by said time control mechanism at a predetermined later time.

3. In a burner control apparatus of the character described, the combination of a main burner, a pilot burner by which said main burner is ignited, a conduit through which gaseous fuel is supplied to said main burner, a safety control valve mechanism operative to control the supply of fuel to said main burner interposed in said conduit, a solenoid and operative connections between said solenoid and said safety control valve mechanism, an electro-magnet incorporated in said safety control valve mechanism, said solenoid being operative when energized to set said safety control valve mechanism in condition to supply fuel to said main burner and said electromagnet being operative when energized to maintain said safety control valve mechanism in said set condition, means operable to control the energization of said solenoid, means operable to control the energization of said electro-magnet, a time control mechanism, operative connections between said time control mechanism and said first mentioned means by which said first mentioned means is actuated at a predetermined time by said time control mechanism to energize said solenoid, and operative connections between said time control mechanism and said second mentioned means by which said second mentioned means is actuated by said time control mechanism at a predetermined later time to effect deenergization of said electro-magnet.

4. In a burner control apparatus of the character described, the combination of a main burner, a pilot burner by which said main burner is ignited, an electric ignition element by which said pilot burner is ignited, a conduit through which gaseous fuel is supplied to said main burner, a safety control valve mechanism interposed in said conduit, a secondary conduit extending between said safety control valve mechanism and said pilot burner through which gaseous fuel is supplied to said pilot burner, said safety control valve mechanism being operative to control the supply of fuel to said main burner and said pilot burner, a solenoid and operative connections between said solenoid and said safety control valve mechanism, a thermocouple disposed adjacent said pilot burner in position to be heated thereby, an electric circuit between said thermocouple and said safety control valve mechanism, a normally open valve interposed in said secondary conduit, a second solenoid operative when energized to close said normally open valve, said solenoid being operative upon energization thereof to set said safety control valve mecha-' nism in condition to supply fuel to said main burner and said pilot burner and said thermocouple being operative when heated to maintain said safety control mechanism in said set condition, switching means operative to control the energization of said solenoid and said electric ignition element, a switch operative to control the energization of said second solenoid, a time control mechansm, operative connections between said time control mechanism and said switching means by which said switching means is set by said time control mechanism in condition to energize said solenoid at a predetermined time, and operative connections between said time control mechanism and said switch by which said switch is set by said time control mechanism in condition to energize said second solenoid at a predetermined later time.

5. In a burner control apparatus of the character described, the combination of a main bumer, a pilot burner by which said main burner is ignited, an electric ignition element by which said pilot burner is ignited, a conduit through which gaseous fuel is supplied to said main bumer, a safety control valve mechanism operative to control the supply of fuel to said main burner interposed in said conduit, a secondary conduit through which fuel is supplied to said pilot bin'ner, a solenoid and operative connections between said solenoid and said safety control valve mechanism, a thermocouple disposed adjacent said pilot burner in position to be heated thereby, said solenoid being operative when energized to set said safety control valve mechanism in condition to supply fuel to said main burner and said thermocouple being operative when heated to maintain said safety control valve mechanism in said set condition, means operable to control the energization of said solenoid, means independent of said safety control valve mechanism operable to extinguish said pilot burner, a time control mechanism, operative connections between said time control mechanism and said first mentioned means by which said first mentioned means is actuated by said time control mechanism to effect energization of said solenoid at a predetermined time, and operative connections between said time control mechanism and said second mentioned means by which said second mentioned means is actuated by said time control mechanism at a predetermined later time.

6. The burner control apparatus as set forth in claim in which said first mentioned means includes a normally open switch and a normally closed switch disposed in series with each other.

'18 includes a normally open solenoid operated valve interposed in said secondary conduit.

9. The burner control apparatus as set forth in claim 5 in which said second mentioned means includes a solenoid operated valve interposed in said secondary conduit.

10. In a burner control apparatus of the-character described, the combination of a main burner, a pilot burner by which said main burner is ignited, an electric ignition element by which said pilot burner is ignited, a conduit through which gaseous fuel is supplied to said main burner, a safety control valve mechanism operative to control the supply of fuel to said main burner interposed in said conduit, a secondary conduit through which fuel is supplied to said pilot bumer, a solenoid and operative connections between said solenoid and said safet control valve mechanism, an electro-magnet incorporated in said safety control valve mechanism, a thermocouple disposed adjacent said pilot burner in position to be heated thereby and an electric circuit between said thermocouple and said electro-magnet, said solenoid being operative when energized to set said safety control valve mechanism in condition to supply fuel to said main burner and said electro-magnet being operative when energized to maintain said safety control valve mechanism in said set condition and said thermocouple being operative when heated to energize said electromagnet, means operable to control the energization of said solenoid, means independent of said safety control valve mechanism operable to extinguish said pilot burner, a time control mechanism, operative connections between said time control mechanism and said first mentioned means by which said first mentioned means is actuated by said time control mechanism to effect energization of said solenoid at a predetermined time, and operative connections between said time control mechanism and said second mentioned means by which said second mentioned means is actuated by said time control mechanism at a predetermined later time.

11. In a burner control apparatus of the character described, the combination of a main burner, a constantly burning pilot burner by which said main burner is ignited, a conduit through which gaseous fuel is supplied to said main burner, a safety control valve mechnism operative to control the supply of fuel to said main burner interposed in said conduit, a solenoid and operative connections between said solenoid and said safety control valve mechanism, a thermocouple disposed adjacent said pilot burner in position to be heated thereby, an electric circuit between said thermocouple and said safety control valve mechanism, a switch in said circuit, said solenoid being 0perative when energized to set said safety control valve mechanism in condition to supply fuel to said main burner and said thermocouple being operative when heated and said switch is closed to maintain said safety control valve mechanism in said set condition, a second switch "by which the energization of said solenoid is break the circuit between said thermocouple and said safety control valve mechanism.

12. In a burner control apparatus of the character described, the combination of a main burner, a constantly burning pilot burner by which said main burner is ignited, a conduit through which gaseous fuel is supplied to said main burner, a safety control valve mechanism operative to control the supply of fuel to said main burner interposed in said conduit, a solenoid and operative connections between said solenoid and said safety control valve mechanism, an electromagnet incorporated in said safety control valve mechanism, a thermocouple disposed adjacent said pilot burner in position to be heated thereby and an electric circuit between said thermocouple and said electro-magnet, a switch in said circuit, said solenoid being operative when energized to set said safety control valve mechanism in condition to supply fuel to said main burner, said electro-magnet being operative when energized to maintain said safety control valve mechanism in said set condition and said thermocouple being operative when heated to energize said electro-magnet, a second switch by which the energization of said solenoid is controlled, a time control mechanism, operative connections between said second switch 20 and said time control mechanism by which said second switch is set by said time control mechanism to energize said solenoid at a predetermined time, and operative connections between said time control mechanism and said switch by which said switch is opened at a predetermined later time by said time control mechanism to break the circuit between said thermocouple and said electro-magnet to effect deenergization thereof.

CHARLES M. MAYER.

JOHN M. HOFF.

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

UNITED STATES PATENTS Number Name Date 2,055,384 Meacham Sept. 22, 1936 2,125,473 Vaughn Aug. 2, 1938 2,249,442 Thornbery July 15, 1941 2,315,773 Couzens Apr. 6, 1943 2,315,774 Couzens Apr. 6, 1943 2,318,801 Ray May 11, 1943 2,353,042 Koch July 4, 1944 2,408,673 Moorhead Oct. 1, 1946 2,544,454 Gauger Mar. 6, 1951