US2275962A - Safety ignition and control device - Google Patents

Description

March 10, 1942.

G. HERBSTER 2,275,962

SAFETY IGNITION AND CONTROL DEVICE FOR BURNERS Filed Feb. 2, 1938 4 Sheets-Sheet l INVENTORQ 1 GEORGE HERBSTER Ea ATTORNEY:

March 10, 1942. HER S ER 2,275,962

SAFETY IGNITION AND CONTROL DEVICE FOR BURNERS Filed Feb. 2, 1938 4 Sheets-Sheet 2 I Q Fig.3

INVENTOR. v GEORGE HERBSTER G. HERBSTER 2,275,962 SAFETY IGNITION AND CONTROL DEVICE FOR BURNERS March 10, 1942.

Filed Feb. 2, 1938 :4Sheets-Shee t s INVENTOR. GEORGE HERBSTER 2" ATTORNEY.

March 10, 1942. s. HERBSTER 2,275,962

SAFETY IGNITION AND CONTROL DEVICE FOR BURNERS I Filed Feb. 2, 1958 4 Sheets-Sheet 4 INVENTOR. v GEORGE HER BSTE R,

I ATTORNEY.

Patented MarJO, 1942 SAFETY IGNITION AND CONTROL DEVICE .FORB .1:

George Herbster, Cleveland, Ohio, assignor to John fi Leonard, trustee, Cleveland, Ohio Application February 2, 193a, Serial No. 188,336

4 Claims. (cl. 158117.1)

This invention relates to a safety ignition and control device for a fuel burner and particularly for a burner which is located so that it is not readily accessible ,to or visible toanoperator.

For the purposes of illustration, the invention isdescribed hereinin connection with a service burner for a domestic gas range cooking oven,

its use in connection with other types of bumers-being readily apparent in theexemplary description and drawings.

Domestic gas range ovens constitute a fire and explosion hazard due to the fact that the oven burner occasionally is extinguished by drafts or temporary reduction in gas line pressure with a resultant accumulation of gas in the oven compartment; a

Attempts have been made to insure proper ignition of the oven service burner at all times by the provision of gas burning pilot burners which operate continuously. Since such pilot burners operate continuously, economy requires that they be adjusted to produce a very small flame. Consequently, the pilot itself is extinguished easily and cannot be relied upon as a complete safety ignition device for a service burner.

Again, since an oven service burner is not readily accessible and visible to the operator of the range, it is not unusual for the operator-to be unaware that the service'burner is not ignited until an explosion occurs, or the kitchen or room is filled with a hazardous accumulation of gas.

In domestic gas cooking ranges, thermostatic oven temperature controls have been provided,

these controls being arranged to be set by a suitable indicating dial to provide different degrees of temperature desired and to maintain the set temperature either byreducing the gas supply to the service burner or by temporarily shutting ofi gas supply of the service burner. While these controls are very desirable for the purposes intended, they increase the explosion hazard due to the fact thatpsometimes after shutting off of the gas, or reduction of the supply to the bumer to such an extent that the burner becomes extinguished, the subsequent supply of gas does tion;

the usual manual gas cock for admission of fuel to the burner.

A correlative object is to supply ignition sparks in firing relation to a burner for re-igniting the burner automatically upon the burner becoming extinguished for anyreason; and, in the event the burner is not -re-lgnited with reasonable promptness, to block entirely the supply of fuel thereto.

A more specific object is to provide a deVice for producing electrical sparks in firing relation to a burner, and thermally responsive means operated by the heat produced by the burner to cause cessation, of the production or such-sparks when the burner becomes ignited and has heated the thermally responsive means to a predetermined degree.

Another specific object is to provide a device for the purposes described which employs a pilot v burner which is readilyaccessible and visible to an operator of a range and which, as a condition precedent to its operation, necessitates the proper operation ofa burner remote from it whereby it indicates at all times to the operator that the remote burner is operating properly, or, that the remote; burner is extinguished. I

Other objects and advantages will become apparent fromthe following specification, wherein switch, showing the valve and switch in fully open position;

Figures 4 and 5 are enlarged cross-sectional views taken on planes indicated by the lines 4-6 and 5 -5, respectively, in Figure 2;

"Figure 6 is a view similar to Figure 1, illustrating a modification of certain parts of the inven- Figure l is a. plan view of the device and associated burners illustrating the relation among the various parts for effecting remote control of one of the burners, part of the device being shown in section for cleamess in illustration;

burner consequent upon turning or opening of Figure 8 is a diagrammatic illustration of an electric circuit which may be used in connection with the present invention.

Referring first to Figures 1 to 5, inclusive, the invention is shown in connection with a service. burner and a pilot bilrner 2 arranged in firing relation to the service burner I. The admission of gas to the burners I and 2 is controlled initially by the usual rotatable stop cock'3 to which gas from a suitable main line is supplied through I a gas inlet passage 4. The gas cock 3 is connected by a pipe 5 to the pilot burner 2 in a manner' such that when the gas cock 3 is turned to its on position gas is admitted to the pipe 5. Connected in the pipe 5 between the gas cock 3 and pilot burner 2 is a pressure operated auxiliary valve 6 which normally blocks the passage of gas through the line 5. The valve 6 has a duct 1 through which gas may flow from the portion of the pipe 5 which is adjacent the cock 3-to the portion of the pipe 5 which connects with the valve 6. Mounted in the valve 6 is a large diameter piston 8 the under side of which is exposed to the full pressure of the gas from the gas cock 3. The piston has a depending needle valve 9 which is rigid with the piston and normally seats in the inlet end of the duct 1 and blocks the passage of gas through the duct. The valve 9 is normally seated by gravity or a light spring (not shown). The piston 8 is operative when gas is admitted to'the valve Bfrom the gas cock 3 to be lifted by the gas pressure on the under side of the piston 8 and thus to lift the needle valve 9 and connect the portions of the pipe 5 for admitting gas to the pilot burner 2.

Mounted on the piston 8 and movable therepositions.

connected to the body -at one sideof the valve seat and the pipe l8 being connected to the body at the opposite side of the valve seat. Within the body is a valve disc 22 having a stem 23 which is mounted slidably in the body 20- for moving the valve disc 22 to open and closed Mounted on the valve body is a supporting member having a tubular body 24 disposed in coaxial relation to the stem 23. The body 24 -is open at both ends and, at the end opposite with is a rod [0- of electrical insulating material 8 lowers until the needle valve 9 seats in which position the contact H is moved out of connecting relation to the contacts l2 and I3, thus opening the circuit therethrough. Accordingly, upon turning the gas cook 3 to open position-gas is not admitted to the pilot unless there is sufiicient pressure in the pipe 5 to raise the piston 8. The piston and the pilot burner 2 are so related to the gas line pressure to be used therewith that the piston can rise and open the valve and close the auxiliary switch only when there is sufiicient gas pressure to maintain the proper flow of gas to the pilot burner 2. Leadingfrom the gas cock 3 is'a pipe l5 by which gas is supplied for the service burner I. The pipe I5 is connected to any suitable thermostatic oven temperature control 16 between the cock 3 and burner l. Beyond the control 15, the pipe [5 is connected I to a thermostatically operated stop valve, designated generally as I1. The pipe l5 enters the valve l1 in such a manner that when the thermostatic control means thereof are unheated,

the valve is closed and prevents the flow of fuel to the service burner I, but when the thermolstatic control means are heated, the valve 11 is opened and permits the flow of fuel to the service burner I through the extension pipe 18.

The valve 11 comprises a hollow body 20 having therein a valve seat 2|, the pipe l5 being from the valve body 20, has a yoke 25, Bimetal thermostatic levers 25 are pivotally connected by their ends to the freeends of the arms of the yoke 25, respectively, and the opposite ends of the levers 26 are pivotally connected to the free ends of the arms of the yoke 21, respectively. The device is positioned so that the thermostatic levers 26 are in heating relation to the pilot burner 2, the configuration and positioning of the levers being such that upon heating of the levers by the burner 2, they move the yoke 21 away from the pilot burner 2 and toward the valve body 20,and upon cooling of the thermostatic levers 26, they move the yoke 21 toward the burner 2 and away from the valve body 20 to the normal position illustrated in Figure 1. F

The tubular body 24, being open at both ends, permits relatively cool outside air to be drawn therethrough so that the parts are protected from heat and the thermostatic levers 'are cooled more readily and thereby rendered more quickly responsive when the device extends into a closed oven compartment.

' Carried by the yoke 21 is a block 28 of electri cal insulating material having high di-electric properties. Secured by one of'its ends in the block 28 and extending axially of the tubular body 24 is a metal rod 29 which is preferably of the type of wire used for the spark terminals in the ordinary automobile engine spark plug.

One end of the rod 29 provides a high capacity discharge spark terminal and is positioned sufficiently close to the burner as to provide a spark gap across which a high frequency spark may jump from the end 'of the rod 29 to the burner 2 when the burner is grounded and a high capacity current is imposed upon the rod 29. This gap is preferably of a width such that when the thermostatic levers 26 become heated by the burner 2 and move the yoke 21 and, consequently, the rod 29 away from the burner 2 a sufiicient degree to open the valve 11 an appreciable extent, as is later described herein, the gap between the end of the rod 29 and the burner 2 is increased to an amount beyond a predetermined maximum spark-gap and the spark cannot jump from the rod 29 to the burner 2 High capacity current is imposed upon the rod 29 through a metal ring 30 which is supported by but electrically insulated from the tubular body 24. The ring 30 very loosely accommodates the rod 29 and is connected by a suitable wire 3| to a source of high frequency curre t, care being taken to provide a sufficient amo nt of insulation, as illustrated, between thenvire 3t and the tubular body 24 to maintain the. spacing of thewire 3| and the body 24 greater than thepredetermined maximum spark gap which the high capacity current can jump.

Interposed between the outer end of the valve stem 23 and the adjacent end of the rod 29 is an interponent 32 of electrical insulating material. The interponent 32 is connected fixedly to the valve stem 23 and to'the rod 29 so that the movement of the rod toward the valve body 20 opens the valve and movement of the rod in the opposite direction closes the valve. Secured to the interponent 32 for movement therewith is an annular flange 33 of insulating material. In order to provide a-main switch for controlling the high capacity current, annulus or ring contact 33 of suitable electrical conducting metal is carried on the outer periphery of the flange 33. At the opposite end of the interponent 32 is a flange. 35, the flanges 33 and 35 providing opposed shoulders between which is slidably mounted on the interponent a switch element 36 in the form of a sleeve of insulating material. Segmental contacts 31 ofelectrical conducting material are carried on the element 36 and are arranged to be engaged by the ring contact 33 so that the ring contact 33. bridges between the contacts 31' and completes the circuit from one contact 31 to the other. The sleeve switch element 36 is of less thickness than the'distance between the opposed shoulders of the flanges 33 and 35 so that the sleeve switch element may slide endwise of the interponent 32 a limited amount. Spring contact arms 33 are carried by the 'body 23 and yieldably engage the segmental contacts 31 of the switch element 36 forsupplyingelectrical current thereto. The spring" contacts 38normally yieldably resist endwise movement of the sleeve switch element 36 in either direction. In the normal starting position illus-' trated in Figure -1, the contacts 31 of the sleeve switch element 33 are in contact with the conflange 35. Thereupon the contacts 33 and 31 are moved with the rod-29 in the valve opening direction while remaining in a predetermined maximum spaced relation to each other. Thus, upon initial movement of the rod 29-to'ward the valve body2il, the main switch provided by the contacts 33 and 37 is immediately opened. Con-.

tinued movement of the rod in the same direction increases the opening of the switch to a predetermined maximum amount, after which the entire main switch moves with the rod 23 uponcontinued movement of the rod in the same direction. Therefore, regardless of the, amount of movement of the rod 29 toward the body- 20 of the valve, only a predetermined maximum amount of movement of the rod in the opposite directionis necessary to re-establishcontact between the contacts. 34 and the contacts 31, and no appreciable delay can occur in re-establishing the spark if the burner 2 extinguished. Here itshould be noted that the end of the rod 23 nearest the burner 2 is so positioned that the'gap betweenithe burner 2 and the rod 23 preferably exceeds the predetermined maximum spark gap only when the valve 23 iS fll11y open being connected to the lit) volt alternating cur-' rent supplied by the wires 4|. If desired, a

transformer may be interposed between the device 40 and the source of alternating current 4|. Connected inseries with the spark-producing circuit of the dewice 40, as is described more fully hereinafter, are the spring contact arms 38, and their associated contacts 34 and 31, and also the contacts i2 and I3 with their associated contact II. The circuit rendering the spark device 40 operative necessitates the closure both of the contacts 34 and 31 with respect to each other and of the contacts 82 and [3 by the contact H, Only when all of these' contacts are in circuit closing position is the device 40 rendered operative for producing a high capacity discharge spark at the spark terminal end of the rod 29adjacent the pilot burner 2. If the contacts 36 and 32 are open or-the contact II is'out of bridging relation to the contacts l2 and I3, or both, no spark will be produced.

' Operation in contact, a circuit is'established for energizing the high capacity discharge spark producing means 30 which, through the wire 3|, imposes a high capacity current on the rod 29. The high capacity current circuit is grounded at one side and due to the metal pipe connection of the pilot;

burner 2 it also forms a ground so that'a spark or continuous series of sparks jump from the rod 29 to the burner 2 igniting the gas issuing therefrom. Obviously, if the gas line pressure is below a predetermined minimum, gas will not be admitted to the burner 2 and the control circuit will not be completed through the contacts I2 and i3. Consequently, neither the spark nor the flow of gas will occur. Upon-ignition of the pilot burner-2, however; the thermostatic levers 26 become heated and move the rod 29 to break the contact between the contacts 34 and 37 so that the spark from the terminal end of the rod 29 to the burner 2 is arrested or discontinued.

In event the contact elements 34 and-31 become and thus is an additional assurance that the spark will be discontinued and re-established,

if for some reason the switchodefined by the contacts 33 and 3? fails to operate properly.

The source of high capacity current may be any suitable one of the various electrical de-l current and spark is indicated at 43; this device therod will increase the gap at theburner 2 to such an extent that no further. spark will be produced, thus providing an additional safety feature. This same movementof the rod, however, for breaking the circuit between the contacts 33 and 37 opens the valve 22 and admits gas to the'service burner which is immediately ignited by the pilot burner 2. In event "the pilot burner 2 becomes extinguished for any reason, the therunostatic levers 26 cool, re-establishing the spark between the rod 29 and the pilot burn r2 and thus re-igniting the burner 2. But if or some reason the pilot burner 2 cannot be or is:not reigriited', the thermostatic levers 26 will cool to a .suficient degree toclose the valve 22. Inthis connection, the follow-up "relation between the sleeve switch element 36 andthe flange switch a short movement is necessary before contact is established between the contacts 34 and 31.

Ordinarily, it is desired at all times that the pilot and service burner combination be used. However, if mere ignition is desired without the safety features, it is apparent that the pilot .burner may be omitted and the rod 28 .used directly for the ignition of the service burner I.

Referring next to Figure 6, a combination similar to that above described is illustrated, except that the pipe line 50 leading to the pilot burner is connected to a valve 5| which corresponds to the valve 20 instead of being connected directly to the gas cock 52. Referring further to Figure 6, there is shown a further modification in that a switch 53 which is operated directly by the gas cock is used instead of the switch defined by contacts |2 and l3. In this form a contact member 54 is arranged on and for rotation with the handle 55 of the gas cock for closing acircuit through stationary contacts 56 when the gas cock is rotated to open position, the contacts 56 and 54 performing the same function as the contacts l2 and I3. Thus a circuit 'is established simply by tuming'the handle 55 of the gas deck 52 *to on position. This circuit is broken by opening of the contacts 51 and 58 when the pilot burner has become ignited.

Referring next to Figure '1, there is illustrated a safety ignition system employing two thermostatically controlled valves each of which is similar to that described in connection with Figure 1.-.' The particular modification illustrated in Figure? is for use where it is desired to utilize a pilot which is located on the top of the range or "some other point which is readily accessible and visible to the operator for controlling the operations of a burner which is remote from or concealed from an operator, for example, "in the ovenof the range. In Figure 7, an oven burner 8| and a second pipe 84 leads to the thermostatically controlled valve of the oven burner. The pilotburner 6| is ignited by a spark produced by a rod or movable high frequency terminal 85 which is connected to a source or means for producing the high capacity discharge spark in the same manner as the rod 28 heretofore described. The connection between the rod 65 with the high pressure source is through the electric wire 68 connected to a terminal 61 of the high capacity discharge spark producing device or means 68. The rod 65 is connected for movement with a yoke 88 to the arms of which are connected thermostatic levers 10. The op-' posite ends of the levers 18 are connected to the free ends of a yoke H fixedly mounted on the body- 12 of a control valve having a seat '|3 in the valve body 12. A cooperating valve disc -14 is carried by the rod and is'opened upon heating of the thermostatic levers IQ of the pilot burner 6|. Leading fromthe pilot burner gas supply line 63 is a branch line-15.which is connected with the body 'IZ at one side of the valve seat 13. Leading from the valve body 12 at theopposite side of the valve seat is a pipe line 16 which leads to a tell-tale pilot burner H which may be located on top of the range or wherever it is readily accessible to the operator. It is apparent that before any gas can be admitted to the accessible pilot ILthe pilot 8| first must be in operation and must have heated the thermostatic levers 18 to a suflicient degree to cause them to unseat the valve disc 14. Arranged adjacent the pilot burner 11 is a valvedevice corresponding in all respects to the valve and thermostatically controlled device, including the rod 28 and valve 28, illustrated in Figure 1. The valve 88 is provided with a movable high capacity terminal rod 8| arranged close to and in spaced relation from the burner 11 so as to provide a spark gap. The rod 8| is also connected to the high capacity discharge terminal 81 of the high frequency device 88 by a wire 82. -The spark gap between the movable terminal andthe burner 8| is normally less than the spark gap between the movable terminal 8| and the burner 11 so that when the. high capacity terminal 6'! is energized, a spark will be produced only between the movable terminal 85 and the burner 8| rather than between the'terminal 8| and the burner However; upon heating of th thermostatic levers 10, the terminal 65 is moved away from the burner 6| to a greater distance than the normal gap between the terminal 8| and burner 11. This occurs only. upon ignition and burning fdraoshort interval of the burner Gl. Consequently, a spark is first delivered to the burner 8| for igniting the gas and as soon as the gas is ignited, the spark is discontinued at the burneril and established at-the burner 81, and, at the ,same time, the valve "is opened to admit gas to the pilot burner 11. Thereupon, thetelltale pilot burner TI. becomes ignited and the thermostatic levers '84 being inheating .relation to the burner 'Il, move the movable terminal 8| away from the burner 11 to such a degree thatthe spark can no longer jump the gap. Consequently, the spark is discontinued both at the terminal 85 and at the terminal 8|. Concurrently with this operation'bf the movable terminal 8| by the thermostatic levers 84, however, the main control valve 85 is opened by the lever 84 for-admitting gas to the serviceburner which is then ignited by the bumeril.

It is often desirable, however, as explained heretofore, that thehigh pressure device be en.- tirely disconnected from the source of power when it is not being used for producing the high capacity discharge sparks. In order to open the circuit-to the device 88, a switch mechanism including, contacts 81 and 88 and movable contacts 88 and 88 are operative'ly associated with the rod 8|, these contacts and associated switch elements-corresponding to the contacts and elements 33 to 38, inclusive, of the switch described in connections with Figure 1.

Connected in series .with the switch composed of.the elements 81 to 88, inclusive, is an additional switch 8| which is operated to close the circuit when the gas cook 62 is turned to on" position. The switch 8| comprises contacts 82 and 83 with an annular contact segment 84 rotatable with the stop cock stem for bridging the Referringnext to Figure 8, the circuit and operating parts comprising one form of high capacity discharge spark producing device are illustrated diagrammatically. A 110 volt alternating current is supplied to the device from the 110 volt supply line 4|. One line of the 110 volt supply is connected ,to a condenser I00, theopposite side of which condenser is connected to a ground. The same line is also connected to a coil IOI which operates the vibrating reed I02, the reed being an electrical conductor. The reed makes and breaks contact with a contact a. I03. A wire I04 leads from the contact l03 and connects it to one terminal of a primary winding I05.

' The opposite terminal of the primary winding I05 is connected to the opposite side of the 110 volt circuit by a wire I05. The two switches heretofore described are connected in series with the last mentioned terminal of the coil I05, these establish the spark, it is necessary that both of I the series connected switches be closed. Between the primary winding I05 and the nearest one of the switches, the wire I 05 is connected by a wire I01 to a condenser I08, the opposite side of which is grounded. A wire I09 is con" nected to the wire I'I between the primary wind-"- ing I and condenser I08 and to one side ofl the condenser IIO, the opposite side of which condenser IIO being connected to that terminal of the coil I0l whichis between the coil IM and the vibrating reed I02, as indicated at III.- A secondary winding H2 is positioned-in inductive relation to the primary winding I05 and one terminal of the secondary winding H2 is connected to the terminal of the coil I05 between the coil I05 and the contact I03. The winding H2 is provided with a metal pole piece 3 to which is connected the wire 3I. The other terminal of the'secondary winding H2 is connected to the metal pole piece H3. The wire 31 is connected to the movable terminal or rod 29, which,

first burner terminal is inoperative until the gap of the second pilot burner terminal is made greater than the gap of the first, thermostatic means in heating relation to the pilot burners respec- 5 tively and operated when heated to. move the associated terminals away from the associated pilot burners and beyond said maximum, valve means operated by the thermostat means of the second pilot burner when the last mentioned thermostat means is heated to admit fuel to the first pilot burner, and valve means operated by the thermostat means of the first pilot burner when the last mentioned thermostat means isheated to admit fuel to the service burner, whereby the readily accessible first pilot burner cannot be ignited for admitting fuel to the service in the circuit arranged to close the same, said switch having a contact fixedly connected to a movable member of the thermostat and another contact having a limited lost-motion connection with the movable member of the thermostat, and

- means resisting but up: preventing movement of the second mentioned contact away from the first, whereby the circuit can be broken by ini: tial movement of the movable member in onedirection and re-estalilished upon taking up of the lost motion by movement of the member in the opposite direction irrespective of the extent of movement of the member in the first direcemitted therefrom and cooperating ground conductor means for the terminals; a single source of high potential current connected electrically to both terminals, both terminals being in sparkin turn, through.the spark gap, completes the capacity discharge spark device may be-used.

In this modification it is apparent that at all times the readily accessible tell-tale pilot is burning and the operation of the igniting pilot or remote burner and the service burner is assured and proper operation of the latter is indicated;

Having thus described my invention, I claim:

1. An ignition device for a service burner com-' prising a pilot burner readily accessible to an operator, means for admitting fuel to said pilot burner, a second pilot burner'remote from the first pilot burner and in firing relation to the service burner, electric spark terminals associated with the pilot burners, respectively, each terminal being spaced from its associated pilot burner and providing a spark gap for igniting its associated pilot burner when the spark gap is less than a predetermined maximum, high frequency electric spark producing means connected to said terminals, the spark gap for the second pilot burner normally being less than that for th first pilot' burner and both gaps normally delivering relation to their respective, ground means, one terminal being initially spaced closer to its ground means than is the other terminal to its ground means so that the former only is initially effective to deliver spark, a thermostat motor in heat-receiving relation to one of the burners and connected to said one spark terminal in amanner to separate said one terminal from its ground means a greater distance than the spacing of the other terminal from its ground being less than the maximum, whereby the sec-,

means whenthe thermostat motor is heated'b said burner, whereby gas will be ignited at said other "burner only after gas has been ignited at said one of the burners.

4."A gas ignition and control system for a service burner comprising two pilot burners, one pilot burner in igniting relation to the service burner and the other pilot burner remote from the service burner, thermally responsive-means operatively associated with said one pilot burner for controlling flow of gas to said other pilot burner, a valve for controlling the fiow of gas to the service burner, thermally responsive means operatively associated with said other pilot burn er for operating said valve, and igniting means in igniting relation to said'other pilot. burner and rendered operative consequent upon predetermined heating of the, thermally responsive means of said one pilot burner for igniting the said other pilot-burner.

GEORGE HERBSTER.

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