US3468298A - Gas stove - Google Patents

Description

Sept. 23, 1969 w TEAGUE, JR ET AL 3,468,298

GAS STOVE 5 Sheets-Shem Filed Jan. 23, 1967 INVENTORS WALTER DORWIN TEAGUE, Jr.

ANTHONY P. MONTALBANO BY CHARLES W. FROMM ATTORNEYS Se t. 23, 1969 w. D. TEAGUE, JR.. ET 3,458,298

GAS STOVE Filed Jan. 23, 1967 5 Sheets-Sheet 2 ATTORNEYS p 1969 w. D. TEAGUE, JR. ETAL 3,433,293

GAS STOVE Filed Jan. 23, 1967 3 Sheets-Sheet 5 o I g Q Q E a Q "v INVENTORS WALTER DORWIN TEAGUE,Jr. ANTHONY P. MQNTALBANO BY CHARLES W. FROMM ATTORNEYS Unite US. Cl. 12639 9 Claims ABSTRACT OF THE DISCLOSURE A gas range or flat-top stove is disclosed wherein the gas and air are supplied to infrared burner units under pressure. The pressurized air fiows through an air control valve for each burner unit and thence to a venturi unit where the gas is mixed with the air. The flow of gas is controlled in accordance with the pressure of the air flowing to the venturi unit so as to insure the proper air-gas ratio. A special gas valve is provided which cuts off the supply of gas when the air control valve is closed, the products of combustion are confined to an exhaust path.

This invention relates to gas stoves, and more in particular to flat-top stoves or cooking ranges where food is cooked in utensils by gas burner units. The illustrative embodiment of the invention is a household or commercial cooking range having a plurality of infrared burners which are supplied with air and gas under pressure.

An object of this invention is to provide improved stoves, particularly cooking ranges of the household and commercial types. Another object is to provide a highly eflicient and dependable system for supplying the desired gas-air mixture to burner units. A further object is to provide stove and range constructions which are sturdy and compact, and which are eificient and dependable in operation under varying conditions of use. These and other objects will be in part obvious and in part pointed out below.

In the drawings:

FIGURE 1 is a perspective view with parts broken away of one embodiment of the invention;

FIGURES 2 and 4 are sectional views respectively on s the lines 22 and 44 of FIGURE 1;

FIGURE 3 is a sectional view on the line 33 of FIG- URE 2; and,

FIGURE 5 is a schematic electrical control circuit.

Referring to FIGURE 1 of the drawings, a flat-top stove or cooking range 2 has a base shell construction 4 with a flat top 6 in the form of a plate of heat resistant glass which transmits radiant heat as well as heat by conduction. Positioned directly beneath plate 6 are four infrared radiant burner units 8, 10, 12 and 14, which are identical, and of the construction of unit 12 which is shown in FIGURE 4. Stove or range 2 includes a control housing 5 centrally positioned in the front of the base shell construction (see FIGURE 2). Control housing 5 encloses a gas and air control assembly 7 including for each of the burner units an air flow control valve 9, a gas cut-off valve 11, a gas-flow pressure regulator 13 and a gas-mixture venturi 15. Venturi unit 15 maintains a near stoichiometric mixture ratio of the gas and air for infrared radiation operation of its burner unit.

Referring again to FIGURE 1, the operation of each of the burner units 8, 10, 12 and 14 is under the respective control of slides 32, 34, 36 and 38 (see also FIGURE 2) mounted at the top of the control housing 5. These slides are identical and each of them may be moved, as

States Patent 0 represented in FIGURE 1, from the fully closed or olf position of slide 38 to the fully open position of slide 32. Each of these slides controls the supplying of gas and air to its burner unit, and it also energizes the igniter unit. Positioned to the rear of burner unit 14 is a blower 40 which draws in fresh air at 42 and delivers it under pressure through a conduit 44 to an air supply manifold 46 (see also FIGURE 2) of the air supply control assembly 48.

Manifold 46 has a side wall 50 and a top wall 52 which is mounted thereon by a row of screws 53. The bottom of the manifold is formed by a valve plate 54 which has four rectangular openings respectively in alignment with slides 32, 34, 36 and 38, and there is a rim 57 which overlies a flange 59 at the bottom of wall 50. Positioned beneath the manifold is a valve plate 61 which is generally coextensive with valve plate 54 and which has slots in which the slides are mounted. Mounted respectively above and below each of the slides and mounted back to back is a pair of identical Teflon diaphragms 64 and 66. Each diaphragm has a central flat sealing portion (68 and 69, respectively), resting against the surface of the slide and a peripheral flange (70 and 71, respectively). Flange 70 is positioned between flange 59 of manifold 46 and valve plate 54, and flange 71 is positioned between valve plate 61 and a coextensive top surface of control housing 5. As shown best in FIGURES 1 and 3, the valve plates and the manifold are clamped to the top of the control housing 5 by five rows of screws 73 which are parallel to the edges of the slides, respectively, between the slides and at the ends of the manifold. Additional screws clamp valve plate 54 to flange 59. Hence, the periphery of each of the diaphragms is clamped by its valve plate and its central portion is somewhat resiliently supported in contact with the surface of its slide.

Each of the diaphragms has a centrally positioned and somewhat rectangular or oblong opening 72 which is closed by the slide when the slide is positioned in the fully closed position shown. At the left of the center of the slide there is a series of holes or orifices 74 through the slide, which bear sub-numbers 1 to 8. Hence, as the slide is moved to the right from the position shown in FIGURES 2 and 3, hole 74-1 first moves into alignment with or is exposed to openings 72 in its diaphragms 64 and 66, thus to provide an orifice or opening from manifold 46 to manifold 56. Upon further movement additional orifices are exposed to the openings 72 in the two diaphragms, thus providing for the increase of the flow of air into manifold 56, with the maximum being when all of the orifices 74 are exposed to the openings 72.

Diaphragm 64 and 66 provide very satisfactory seals for their respective manifolds, and they provide for free movement so that the slide may be positioned very easily with great accuracy. Also, when there is pressure within the manifold, the diaphragm is pressed against the slide so as to insure the proper sealing. The sizes and positioning of the orifices 74 are such as to provide a predetermined increase in the rate of flow of air into manifold 56 as the slide is moved toward its fully opened position. The slide bears indicia in the form of numbered lines to aid in providing the desired rate of flow. As will be further explained below, the rate of flow of the air determines the rate of flow of the gas to the burner unit and therefore controls the operation of the burner unit from the standpoint of the amount of heat produced. Each of the slides (see FIGURES 2 and 3) has a handle 33 with a main body portion 35 and an upturned flange 37 which is grasped by the fingers to move the slide between the fully closed and fully open positions. It has been found that this particular handle is ideal for quick and accurate adjustment of the slides. Also, when all of the slides are in the fully closed position, the flanges 37 of the various handles are in alignment. Hence, if any of the slides is not in its fully closed position, it will be quickly apparent to the observer.

As shown in the right-hand portion of FIGURE 2, gases are supplied to the stove through a horizontal gas-supply manifold 80 extending along the front of the stove and connected to each of the gas cutoff valves 11. Each of the gas cutoff valves 11 has a nonmagnetic body 82 with the valve closure being formed by a valve seat 84 and a steel ball 86 which is moved from and to the valve seat to open and close the valve. When the valve is in the open position as shown in full lines, gas flows from manifold 80 to the left througha passageway 88 and downwardly around ball 86 and past the valve seat through the valve opening to a gas supply chamber 100. The valve is opened and closed by the action of a cylindrical magnet 90 which is slidable vertically in the housing and guided by a pin 92 mounted at its upper end. Magnet 90 and ball 86 are urged downwardly by gravity and by a coil spring 94 mounted in the upper end of the magnet and they move upwardly only when the magnet is attracted by magnetic material above it. Accordingly, the slide 36 is of magnetic steel and it has a disk insert 06 of non-magnetic material which is moved into axial alignment with magnet 90 when the slide is in the fully closed position. Hence, when a slide is positioned as shown in FIGURE 2 or further to the right, magnet 90 is attracted to the slide and it lifts itself upwardly to the position of FIGURE 2 and carries with it the steel ball 86 so as to open the valve. However, when any of the slides is moved to the fully closed position, the nonmagnetic disk 96 is in axial alignment with magnet 90 and the magnet is no longer drawn upwardly by attraction to the slide and it moves downwardly by the combined action of gravity and spring 94 and closes the valve.

With this arrangement, the first movement of any of the slides from its fully closel position opens its gas cutoff valve 11 so as to permit gas to flow from the manifold 80 to the supply chamber 100. The gas flowing into supply chamber 100 passes through gas-flow regulator 13 and a chamber 104 to the venturi unit 15. Regulator 13 restricts the flow in a manner which is dependent upon the air pressure in manifold 56, namely, so as to maintain the gas pressure in chamber 104 at all times equal to the air pressure in manifold 56. Regulator 13 has a movable member 106 carried upon a stem from a diaphragm 108. Diaphragm 108 is urged upwardly by the gas pressure in chamber 104 with the aid of a coil spring 110, and it is urged downwardly by the pressure of the air in a chamber 112 above the diaphragm. Chamber 112 is connected to manifold 56 through a small opening 114, so that the air pressure in chamber 112 is the same as in manifold 56, except that the small size of opening 114 dampens the response to changes in the air pressure. Hence, when the air supply to a manifold 56 is reduced, the reduced pressure in chamber 112 permits spring 110 to move member 106 upwardly so as to reduce the rate of gas flow. However, when the slide is moved outwardly so as to increase the rate of air flow, the pressure in manifold 56 is increased and there is the same increase in the pressure in chamber 112 which acts upon diaphragm 108 to increase the gas flow. In this way regulator 13 acts automatically at all times to maintain the gas pressure 111 chamber 104 equal to the air pressure in manifold 56.

From chamber 104 the gas flows through orifice 105 to an annular chamber 107 and thence through a plurality of radial holes 109 where it joins the stream of air flowing to the burner unit. Orifice 105 has the characteristic that when the pressure in chamber 104 is equal to the pressure in manifold 56 gas is delivered to the air stream in the desired ratio. Hence, with the position of slide 36 controlling the rate at which air flows to the burner unit, the air pressure in manifold 56 acts through regulator 13 to produce an equal gas pressure in chamber 104, and

there is a resultant gas flow through orifice which gives the desired gas-air mixture to the burner unit. The respective mass flows of air as W and gas as W; maybe expressed as follows:

F and F are constants, and P represents thepressure in the correspondingly numbered zone.Regulator 13 insures that P equals P Holes 109 are relatively'large iii-relation to the amount of gas flowing through them; so that P in the venturi throat equals P Therefore 5s- 127) i04 io7) and In other words the mixture ratio of gas and air is a constant and depends on the values of F and F The actual value of F 'is dependent onthe size of'the orifice 105 so that by selecting various sizes of-orifice 105 the mixture ratio of gas and air can be varied to 'suit' the particular type of gas available. Also a restricting screw 122 may be adjusted so that its needle end 124 projects into the entrance to the orifice so as'to adapt the orifice for the alternative gas supply. For this'adjustment a screw plug 126 is provided which may be removed. Also, restricting screw 122 may be adjusted so that its needle end'124 projects into the entrance'to the orifice so as to adapt the orifice for the alternative gas supply. For this adjustment a screw plug 126 is provided which may be removed.

Referring to FIGURE 4, burner unit 12 has a cylindrical plenum chamber 16 to which the proper gas-air mixture is supplied through its duct 18, and which has its top closed by a concave infrared burner element 20 of the wire-mesh type. Mounted in the side of hot gas chamber 22 is an ignitor unit 30 which is energized to ignite the burner unit. Extending between the top of plenum chamber '16 is the hot gas chamber 22, the to edge of which rests against the bottom surface of plate 6 and is sealed by a ceramic fiber gasket 24. A flue 26 extends from an opening in hot gas chamber 22 to an exhaust flue, and the elevated pressure permits the discharge of the products of combustion outside the building. Hence, theproducts of combustion need not be discharged in the vicinity of stove. r

FIGURE 5 is schematic and includes a representation of the electrical system. In alignment with each of the slides, there is a switch which is held in its open position by the end of its slide whenever the slide is in the fully closed position. These switches are in parallel, and the closing of any one of them'connects the electrical supply to all of the ignitors 30 and also to the electric motor 112 of the blower. The first movement of any one of the slides from its fully closed position opens its gas cut-oif valve 11, and it also closes its electric switch 110 which energizes blower motor 112' and-the ignitors 30. The ignitors are of a known type which operate with very small current consumption, and it is satisfactoy to energize all of the ignitors whenever any burner unit is being used. However, under some circumstances it is desirable to provide a separate switch for each of the ignitors and to energize each ignitor only when its burner is to be used.

It has been pointed out above that plate 6 is of heatresistant glass which transmits infrared radiation. In producing the glass it is rendered somewhat translucent or opaque so that it prevents viewing the range components beneath the plate, except fora yellow glow when a burner unit is operating, It has been discovered that this glass has a color response to heat, which is very-desirable in this particular use. Whenever one of the burner'units is-opcrating, it produces infrared radiation which passes through the disk portion of the plate 6 above that burner unit, and is viewed by the user. Also, that disk portion of the plate is heated by radiation and conduction-from the hot gases beneath it, and the rise in temperature causes it to turn a greenish color. Hence, that greenish color indicates that the disk portion is hot and is a safety feature by which the user is warned against inadvertently touching the heated disk portion or placing combustible material upon it.

In the illustrative embodiment, the air-gas ratio is of the order of twelve to one at a fuel consumption rate of the order of 12,000 B.t.u. per hour. The elevation above ambient of the air pressure in manifold 46 is of the order of 1.8 to 2 inches of water. The air pressure in manifold 56 is not greater than that in manifold 46, and the gas pressure in chamber 104 is equal to the air pressure in manifold 56. The drop in pressure between chamber 104 and passageways 109 during maximum gas flow is of the order of 5 to 6 inches of water.

Magnet 90 is of the ceramic type which maintains its magnetism without diminution during normal usage. However, when this magnet is heated to a temperature of the order of 450 F. the magnetism is destroyed. Hence, if valve 11 is open and magnet 90 is heated to that critical temperautre, the magnet loses its magnetism, and valve 11 is closed in the same manner as if slide 36 were moved to its off position. Therefore, valve 11 is adapted to act as a safety cutoff valve if it is installed in such a manner as to be heated by the malfunctioning of its burner unit.

What is claimed is:

1. In a gas stove, the combination of, a burner unit, means forming a closed gas discharge chamber above said burner unit through which the products of combustion are discharged and including a top wall through which radiant heat may pass to a top cooking zone, means constituting a supply of gas under pressure, and valve means to control the supplying of the air and gas in the desired mixture to said burner unit, said valve means including air valve means to control the supplying of the air to said burner unit and means responsive to the initial movement of said air valve means from its closed position to activate said means constituting a supply of air under pressure and said means constituting a supply of gas.

2. A stove as described in claim 1 wherein said means constituting a supply of air under pressure is an air blower.

3. A stove as described in claim 1 wherein said valve means includes a cutoff valve for the gas and wherein said air supply valve is adapted to supply air at a selected rate to be mixed with the gas, and a control valve positioned in the path of the flow of gas between said cutoff valve and said burner unit and operative in response to increases in the pressure of air flowing from said air supply valve to provide increases in the flow of gas to said burner unit.

4. A stove as described in claim 1 which includes, a shell construction, a plurality of said burner units positioned adjacent the top of such shell construction, said top wall comprising a horizontal top wall of heat-resistant glass positioned above said burner units to provide a top wall to confine the products of combustion discharged from said burner units, and exhaust means to discharge said products of combustion.

5. In a gas stove, the combination of a shell construction, a plurality of burner units of the infrared type positioned adjacent the top of said shell construction, a horizontal top wall of heat-resistant glass positioned above said burner units and providing a top wall which confines the products of combustion discharged from said burner units, exhaust means to discharge said products of combustion, blower means constituting a supply of air under pressure, means constituting a supply of gas under pressure, and valve means to control the supplying of air and gas in the desired mixture to said burner units, said valve means including for each of said burner units a moveable slide and means operated by the movement thereof which initiates the operation of said blower means when said slide is moved initially from a closed position and thereafter provides increased amounts of air to said burner units upon progressive further movement.

6. A stove as described in claim 5 which includes a magnetic valve which is normally closed to prevent the flow of gas and means which opens said magnetic valve in response to the movement of said slide.

7. A flat-top range comprising, a shell construction having a top wall of material which transmits radiant heat, radiant burner means positioned beneath said top wall and adapted to transmit heat therethrough, blower means to supply air under pressure to said burner means, air valve means which controls the amount of air supplied by said blower means to said burner means, means constituting a supply of gas to said burner means, means responsive to the amount of air supplied to said burner means to control the amount of gas supplied thereto, and heat-control means for said burner means comprising manual means to move said air valve means between a fully closed position and a fully open position and thereby vary the amount of heat produced by said burner means.

8. A stove as described in claim 7 wherein said burner means comprises a plurality of infrared burner units positioned beneath said top wall, and wherein said stove includes means to discharge the products of combustion along a confined path.

9. A flat-top range comprising, a shell construction having a top wall of material which transmits radiant heat, radiant burner means positioned beneath said top wall and adapted to transmit heat therethrough, blower means to supply air under pressure to said burner means, air valve means which controls the amount of air supplied by said blower means to said burner means, means constituting a supply of gas to said burner means, means responsive to the amount of air supplied to said burner means to control the amount of gas supplied thereto, means forming an air header, an air valve connected to said air header and adapted to be moved from a fully closed position to a fully open position and thereby provide for the flow of air from said air header at a progressively increasing rate, means forming an air chamber into which the air flows from said air valve, a venturi unit having a central air passageway extending from said air chamber and having radial gas inlet passageways, gas supply means including a control valve through which gas passes at a controlled rate to said radial passageways where it is mixed with air flowing from said air chamber, means responsive to the air pressure in said air chamber and connected to control the opening and closing of said control valve, and means to deliver the mixture of air and gas from said venturi unit to said burner means.

References Cited UNITED STATES PATENTS 2,806,465 9/1957 Hess. 3,033,463 5/1962 Doner et a1. 3,241,542 3/1966 Lotter. 3,269,450 8/1966 Licata et al 1581 19 X 3,299,938 1/ 1967 Bally et al.

CHARLES J. MYHRE, Primary Examiner US. Cl. X.R. 43 1-328 2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 68,29 Da September 23, 1969 Inventor(s) Walter Dorwin Teague, Jr. Anthony P. Montalbano and Charles W. Fi'omm It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 31, after "zone," insert -means constituting a supply of air under pressure,--.

sit AH) LALEH SEP 2319?!) QSEAL) Attest:

Edward M. Fletcher, II'. E. sum JR. Attesting Officer ommissioner of Patents

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