US2315774A - Burner control system - Google Patents

Description

-PRil 6, 1943- wfM. coUzENs 2,315,774

BURNERy CONTROL SYSTEM A Filed Feb. 19, 1940 2 Sheets-Sheet l 4? April 6, 1943. w. M. coUzENs 2,315,774

BURNER CONTROL SYSTEM Filed Feb. 19, 1940 2 sheets-sheet 2l Patented Apr. 6, 1943 UNITED STATES PATENT ori-ICE BURNER CONTROL SYSTEM E. Gaifers Application February 19, 1940, Serial No. 319,720

(Cl. 16h- 9)E 3 Claims.

This invention relates to controls and relates more particularly to control systems for iluid fuel burners. A general object of this invention is to provide a safe, dependable and effective control system for a uid fuel burner.

The present invention is concerned with automatic controls or timed controls for burners and is particularly suited for embodiment in controls for the burners oi cooking ranges and other appliances utilizing a iiuid fuel such as gas. The improved control system of the invention provides for the operation of a burner for any given or selected period and for the automatic extinguishing of the burner at the end of the time period.

Another object of this invention is to provide a cont-rol of the character mentioned embodying an electrically governed valve inthe burner supply line, a thermo-electric generator supplying current for the operation of the valve and a manually energized mechanical timer readily set or conditioned to provide for any selected-period of burner operation. The burner control system is characterized by the thermo-electric generator actuated by the heat of a flame and the mechani-y cal manually energized timer governing the control circuit of the valve, the generator and the manually energized timer providing for the full and desired contr/ol of the valve without resorting to the use of electrical energy from an external source such as batteries or an electrical utility supply line.

Another object of this invention is to provide f a control system of the character mentioned in which the thermo-electric generator may be actuated by the flame of the pilot burner of the controlled burner to constitute a safety element. Where the thermo-electric generator is actuated by the pilot burner iiame extinguishment of the pilot burneriiame results in de-energization of the generator and the valve controlling circuit so that the valve in the line of the controlled burner cannot be opened when the pilot flame is extinguished.

Another objectof this invention is to provide a burner control system of the character mentioned embodying a mechanical timer adapted to be manually energized and set to provide forimmediate burner operation for any selected period, and a valve controlling the burner which is directly operated by the timer thus eliminating all electrical circuits and electrical control elements. In one form of the invention the control valve for the burner is directly manually operated by the manually energized timer,

greatly simplifying the structure and materially reducing its cost.

A further object of this invention is to provide a burner control system of the type embodying the control valve directly governed by the timerwhich is characterized by a safety thermostatically controlled valve in the line of the burner that automatically closes in the event the pilot name is extinguished thereby preventing a discharge of unconsumed fuel into the cooking compartment or appliance in the event the control system is put into operation when the pilot flame is extinguished.

The various objects and features of my invention will be fully understood from the following detailed description of typical, preferred forms and applications of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a side elevation of a typical cooking range with a portion broken away to illustrate y certain parts oi the burner means and the control system, the electrical circuits of the control being diagrammatically illustrated. Fig. 2'is an enlarged vertical detailed sectional view of the electrically controlled valve. Fig. 3 is an enlarged vertical detailed sectional view of the timer with certain parts in elevation. Fig. 4 is` an enlarged side elevation of the thermo-electric generator and pilot burner unit. Fig. 5 is a front view of the cooking range with a portion broken away to show the burner and control parts in elevation illustrating another form of control system, and Fig. 6 is an enlarged vertical detailed sectional view of the timer and control valve of the system illustrated in Fig. 5 with certain timer parts in elevation.

The control systems of the present invention have many uses and applications and are particularly useful for the control of fluid fuel burners of devices or appliances wherein it is desirable to limit the period of burner operation or the temperatures developed. In the drawings I have illustrated the invention embodied in controls for the burner in the broiler compartment of a typical cooking range. It is to be understood that these are merely typical forms and applications of the invention and that the invention is not to be construed as limited or restricted to the forms or applications herein described.

The cooking range illustrated in the drawings comprises a range body I0 having a cooking compartment or broiler compartment Il and a suitable burner I2 in the compartment. The burner I2 is adapted to handle a fluid fuel such as gas and is horizontally arranged in the compartment II to have its flame jets directed downwardly. A uid fuel supply line I3 enters the range body III and extends to the burner I2. A manually operable valve I4 is connected in the burner supply line I3 and is arranged so that its operating handle I5 is accessible at the front of the range body. The range body I0 is further equipped with the usual upwardly projecting guard rail I6.

The burner control illustrated in Figs. l to 4, inclusive, may be said to comprise, generally, an electrically governed valve I1 in the burner supply line I3, thermo-electric means IB generating current for the operation of the valve I1, and a manually operated timer I9 in the circuit ofthe valve I1 operable to provide for immediate opening of the valve and for burner operation for a selected period.

The valve I1 serves to control the line I3 of the burner I2 and in turn is controlled by the timer I9. The valve I1 includes a body 20 having chambers A and B separated by a partition 2i. The valve body is connected in the supply line I3 so that the chamber A is in communication with the upstream part of the line and the chamber B is in communication with the down stream side of the line. 'I'he valve body structure is sectional including an upper body part 23 that is tubular or hollow to have a third chamber C. A port 22 in the partition 2I is adapted to put the chamber A in communication with the chamber B and a raised valve seat 24 is provided on the partition at the upper end of the port. A iiexible diaphragm 25 extends across the lower end of the chamber C and has a valve disc 26 adapted to cooperate with the seat 24. A weight 21 is provided on the diaphragm 25 to hold the valve disc 26 in cooperation with the seat 24.

The valve I1 includes a pilot valve means for controlling the diaphragm 25. A pair of aligned openings 28 is provided in the upper body section 23 and jets 29 are arranged at the mouths of the openings 28 to project toward one another. The jets 29 have finished end surfaces of limited area. A port 30 passes through the walls of the body 20 and section 23 to connect the chamber A with one opening 28 and a, similar port 3| is provided in the body and the section 23 to connect the chamber B with the other opening 28. An electrically actuated pilot valve 32 controls the jets 29. A sensitive electromagnet or solenoid coil 33 is suitably supported at the upper end of the section 23 to operate or control the valve 32. The valve 32 is a iiapper valve pivoted at X to have one end project between the jets 29 and to have its other end adjacent the core of the coil 33. The valve 32 is biased and supported to normally maintain the position illustrated, where it closes the jet 29 communicating with the chamber B and leaves the other jet open. With the valve 32 in this normal unactuated position the chamber C is in communication with the chamber A and the upstream side of the supply line I3 so that the pressure above the diaphragm 25 is substantially equal to the pressure in the chamber A and the weight 21 holds the valve disc 26 against the seat 24. Operation of the coil 33 reverses the valve 32, closing the jet 29 communicatingwith the chamber A and opening the jet communicating with the chamber B and the fuel under pressure in the chamber C quickly leaks away into the chamber B so that the pressures on the diaphragm 25 are unbalanced and the diaphragm moves upwardly to uncover the port 22 and thus permit the flow of fuel to the 75 chamber B and the burner I2. The coil 33 and the upper portion of the pilot valve 32 are housed in a suitable case 34 secured to the body section 23. The case 34 may serve to close the upper end of the section 23 and may carry the posts or terminals 35 of the coil 33.

The means I8 for generating current for the control of the valve I1 is a thermo-electric generator means. The means I3 embodies or is associated with the pilot burner for the main burner I2 and in accordance with the invention is energized by the heat oi the pilot burner flame. The combined pilot burner and thermo-electric generator is arranged in the cooking compartment I I and comprises a tuber 36 connected in the main supply line I3 by a pipe 31. The pipe 31 is connected in the supply line I3 above the manual valve I5 so that the pilot burner is unaffected by operation of the manual valve or the electrically controlled valve I1. The cute; end of the tube 36 has a tip 31L opposed by a spool 33 of ceramic material, or the like, so that the issuing gas 0r fuel forms an annular ilame about the spool.

The generator portion of the assembly is a multiple thermo-couple comprising a multiplicity of thermo-couples spaced about the tube 33. The thermo-couples comprise pairs of wires or rods of thermoelectrlcally dissimilar metals connected at their opposite ends and the several thermo-couples are connected in series. The outer portions of these thermo-couples are arranged at the burner tip 31* and may have suitable protective caps 39. The outer parts oi' the thermo-couples are maintained at a high temperature by the flame of the pilot burner while the rear or inner parts of the thermo-couples remain at a much lower temperature and this temperature differential provides for the generation of current or an electrical potential. In practice the thermo-electric generator generates about 1A volt of electrical potential. Thermoelectric generators of the type just described are now well known to those skilled in the art and it is believed that the generator requires no further description. An insulated electrical lead 4I extends from one pole of the thermo-electric generator to a pole 35 of the valve coil 33. A second insulated lead 4I extends from the other pole of the generator to the timer I9.

The timer I9 is manually energized to provide for immediate opening of the valve I1 and for continued opera-tion of the burner I2 for any selected period. The timer I9 may be arranged at any selected point remote from the burner I2 and is preferably arranged where it is conveniently accessible and visible. In the construction illustrated the timer I9 is supported by a suitable bracket 42 secured to the top of the guard rail I6. The timer I9 includes a case 43 containing a clockworks mechanism 44 of suitable design embodying the usual energy storing spring. The main shaft 45 of the clockworks mechanism projects from both the front and rear of the case 43. A knob or handle 45 ls keyed or otherwise secured to the shaft 45 at the front of the case 43 and is shaped to form a pointer or hand for moving across a dial 41. 'I'he dial 41 is calibrated to have a series of marks designatingl minutes or other suitable time periods. In practice the dial 41 may have a plurality of minute marks collectively indicating 60 minutes or multiples of hours or fractions of hours with numerals at spaced graduations.

The projecting rear portion of the timer shaft 45 carries a cam disc 48. The disc 48 ls xed to the shaft 45 and has a notch 49 in its periphery. One Wall of the notch 49 is curved or sloping for the purpose to be subsequently described. A second disc 58 is arranged on the shaft 45 under the disc 48 and its periphery has a notch 5|. The notch 5I has straight parallel side walls. The inner disc 58 is free to turn on the shaft 45. A slack connection between the discs 48 and 58 limits turning of the disc 58 with respect to the disc 48. This slack connection may comprise a lug 52 on the disc 48 operating in an arcuate slot 53 in the disc 58. The circumferential extent of the slot 53 is equal to the spacing( of a limited number of calibrations of the dial 41. For example, it may equal the spacing of four or ve calibrations. The inner loose disc 58 is slightly larger in diameter than the disc 48.

An effective switch mechanism is associated with the timer I9 to govern the circuit of the valve coil 33 and when brought into engagement L serve to complete the energizing circuit of the coil. The free or outer ends of the flexible contacts 56 have suitable points and the contacts are formed and mounted so that their points are normally open. A rocker or lever 58 is suitably pivotally supported at the back of the timer case 43. An arm 59 projects from the lever 58 and has a disc or block 68 of insulation engageable with one contact 56 to bring it into engagement with the othercontact. A second projecting arm 6I of the lever 58 has a pin 62 adapted to enter the notches 49 and 5| and adapted to bear on the periphery of the larger disc 50. The parts are related so that the contacts 56 are open when the pin 62 is received in the notches 49 and 5| and the contacts 56 are made or engaged when the pin 62 bears on the periphery of the disc 58. A spring 63 is connected with the lever 58 to urge the pin 62 against the periphery of the disc 50 and to urge the pin into the notches 49 and 5I.

With the knob or handle 46 at zero the pin 62 is in the notches 49 and 5I so that the contacts 56 are open.` When the shaft 45 is turned by means of the handle 46 the sloping wall of the i notch 49 cams the pin 62 outwardly to engage the periphery of the disc 58 and thus pivots the lever 58 so that the block 68 brings the contacts 56 into engagement. The clockworks 44 is manually energized by the above mentioned turning of the handle 46 and serves to turn the shaft 45 to return the discs 48 and 58 to their normal positions so that the pin 62 reenters the notches 49 and 5|. This allows the lever 58 to pivot to the position where the contacts 56 may open. The contacts 56, the bracket 54, and the adjacent parts may be housed in a suitable box 65 attached to the case 43.

Audible signal means may be associated with the timer I9 to indicate the time of closing 0f the valve I1. A bracket 66 supports a bell 61 at the rear of the case 43. A hammer 68 is pivoted to the case 43 in position to strike the bell 61. An arm 69 of the lever 58 is engageable with the hammer 68 to suddenly throw the hammer lli I8 and then passes to the valve I1a.

against the bell 61 when the pin 62 moves into the notches-49 'and 5I.

In the operation of the burner control system of Figs. 1 to 4, inclusive, the valve I4 is normally closed, the valve I1 is normally closed, and the pilot name of the means I8 normally heats the outer portions of the thermo-couples so that the means I8 generates electricity for the operation of the valve coll 33. When it is desired to use the burner I2 the valve I4 is opened and adjusted to provide the desired temperature in the cooking compartment II. The knob 46 is then manually turned to indicate on the dial 41 the time during which it is desired to have the burner I2 in operation, In practice the knob 46 must be turned suiiciently to cam the pin 62 out of the slots 49 and 5I so that the pin bears against the periphery of the disc 58. Camming of the pin 62 from the notches 49 and 5I pivots the lever 58 so that the block 68 closes the contacts 56. When this occurs the circuit to the valve coil 33 is completed and the coil operates the pilot valve 32. Operation of the pilot valve 32 unbalances the pressures on the diaphragm 25 and the diaphragm is lifted by the pressure in the line I3 allowing the fuel to pass to the burner I2. The pilot ame ignites the fuel at the burner I2.

When the timer I9 has been put into operation, as above described, the clock works 44 immediately begins to turn the shaft 45 in a direction to return the notches 49 and 58 to their initial positions. The engagement of the pin 62 with the disc 58 causes the disc to lag behind the disc 48. 'Ihis moves the notches 49 and 58 out of registration. Near the end of the selected interval of burner operation the sloping wall of the notch 49 passes the pin 62, the larger disc 58 serving to prevent the pin from entering the flaring notch 49. When the straight-walled notch 5I reaches the pin 62 the spring 63 acting on the lever'58 causes the pin to suddenly enter the notches 49 and 5|. The sudden pivoting of the lever 58 moves the block 68 out of engagement with the adjacent contact 56 opening the circuit to the coil 33. The sudden pivoting of the lever 58 also operates the hammer 68 providing an audible signal. Opening of the circuit to the coil 33 results in reversal of the biased valve 32 and the diaphragm 25 returns to its normal position where the valve disc 26 closes the port 22. Thus the burner l2 is extinguished at the end of the selected time interval. It will be observed that the manual operation of the timer I9 results in immediate operation of the burner I2 and subsequent continued operation of the burner for any given or selected period.

The form of the invention illustrated in Figs. 5 and 6 may be said to comprise, generally, a valve |12 connected in the supply line I3a of the burner I2, a timer I9@l controlling the valve I1L and a pilot governed thermostaticvalve 18 connected in the supply line |39.

In the construction of Figs. 5 and 6 the burner I 2 may be the same as in the previously described form of the invention being suitably positioned in the cooking compartment I. The supply line I3a for the burner I2 extends to the manually operable valve I4 at the front of the range body The valve I1a may be located as found most desirable.

However, it is preferred to locate the valve I1n where the associated timer I9* is readily accessible and fully visible. In the case illustrated the valve I1a and the timer I9 are carried by a bracket 42a on the guard rail I6 and the supply line i3 of the burner I2 extends from the manual valve I5 to the bracket 42. The bracket 42 illustrated in the drawings comprises spaced posts 1| and the valve |1a and the timer I!!l nre supported between the posts. The posts 1I may be tubular and may form parts of the supply line |33, although this construction may not be preferred in every instance. The line I3n extends from the bracket 42 to the burner I2 in |She cooking compartment II.

The valve |11- is adapted to be directly or mechanically operatedby the timer I9 to control the supply line I3u of the burner I2. The valve Ile includes a body 13 whose end portions are formed for connection with supply line parts. l'n the particular case illustrated pipe parts 14 extend laterally from the spaced arms 1I and ihread into the opposite ends of the valve body 13. A partition 15 extends across the interior of the valve body 13 and has a port 16. A valve stem 11 extends through the port 16 with substantial clearance and passes through a packing gland 18 to project from the body 13. A valve head 19 is secured to the stem 11 and is adapted to engage a suitable seat on the partition 15 to close the port 16. A spring 80 is arranged under compression between the head 19 and a plug 8| which closes the lower end of the valve body 13. The spring urges the valve head 19 to its closed position.

The timer I9a is substantially the same as the above described timer I9 having the case 43, the clock-works M, the operating knob 46, the lever 58 provided with the pin 62 for cooperating with the notches of the discs 48 and 50, the hammer 68 actuated by the lever 58 and the bell 61, all as above described. An operative connection is provided between the lever 58 of the timer I9 and the lever I1a whereby the timer is manually operable to immediately open the valve Il and hold the valve open for a given or selected period. This connection comprises a bell crank 83 pivotally mounted on the valve body 13 and engageable with the outer end of the valve stem 11. A projecting arm 84 of the lever 58 has a link 85 ccnnected therewith 'Ihe outer end of the link 85 is pivotally connected with the bell crank 83 whereby pivoting of thelever 58 causes pivot'ng of the bell crank. The parts are related so that the spring 63 normally holds the lever 58 and the bell crank 83 in positions where the valve head 19 is closed against its seat. Manual turning of the knob 46 results in pivoting of the lever 58 so that the bell crank depresses or shifts the stem 11 to open the valve head 19. The pin 62 engaging the periphery of the disc 50 holds the valve I1 open until the pin is again received in the notches 49 and 5 I.

The thermostatic valve 10, while not essential, is preferred as it prevents the discharge of unconsumed gas into the compartment II in the event the burner control is operated when the pilot flame is extinguished. The valve 10 is connected in the supply line I3n at a point between the valve I1a and the burner I2 and has a thermostatic element or heat responsive element 9U projecting into the compartment I I. A pilot burner 9| is arranged to have its ame in igniting relation to the burner I2 and in heating relation to the element 80. The supply line 82 of the pilot burner 9| is connected with the supply line Il* at the upstream side of the manual valve I4. The Valve 10 and its thermostatic element SII may be of conventional or selected construction. With the pilot burner 9| lit the valve 10 is open. However, if the flame of the pilot burner becomes extinguished the valve 10 automatically closes to prevent the delivery of fuel to the burner I2.

To operate the control and provide for the operation of the burner I2 for a given period the valve |4 is opened to provide for the required temperature in thecompartment II and the handle vor knob 46 is turned to point to the selected time indicia. on the dial 41. Turning of the knob 46 results in pivoting of the lever 58 vand this movement is transmitted to the bell crank 83 by the link 85. Pivoting of the bell crank 83 shifts the stem 11 to bring the valve head 18 to its open position. The disc 60 of the timer holds the lever 53 in the position where the valve I1 is open. Fuel is delivered to the burner I2a until the selected time interval has expired whereupon the pin 62 moves into the notches 49 and 5I with resultant pivotal movement of the lever 58. This pivotal movement of the lever 58 is accompanied by return pivoting of the bell crank 83 and the valve head 19 is closed by the spring 60.

Having described only typical preferred forms and applications of my invention, I do not wish to be limited or restricted to the specic details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art, or fall within the scope of the following claims.

Having described my invention, I claim:

l. A control system for a burner having a supply line and a pilot burner, the system comprising an electrically operated'valve in the supply 'line, an electrical operating circuit for the valve,

a thermo-electric generator energized by the flame of the pilot burner supplying current to said circuit, switch means in said circuit, and a manually energized timer manually operable to close the switch means and hold the switch means closed for a given period.

2. A control system for a burner having a supply line and a pilot burner, the system comprising a normally closed valve in the supply line. electrically operated means for reversing the valve, an electrical operating circuit for said means, a thermo-electric generator energized by the flame of the pilot burner supplying current to the circuit, and a mechanical manually operated timer governing the circuit operable to hold the circuit closed for a selected period.

3. A control system for a burner having a. supply line and a pilot burner, Vthe system comprising a normally closed valve in the supply line, electrically operated means for reversing the valve, an electrical operating circuit for said means, a thermo-electric generator energized by the flame of the pilot burner supplying current to the circuit, a normally open switch in said circuit, and a manually energized' spring driven timer operable to close the switch and thereafter hold the switch closed for a selected period.

WILLIAM M. COUZENS.

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