US3448923A - Fluid fuel flow control for gas burning top burner - Google Patents

Description

June 10V, 1969 D. SAPONARA FLUID FUEL FLOW CONTROL FOR GAS BURNING TOP BURNER Original Filed Dec. 16, 1956 Unted States Patent Odice 3,448,923 Patented June 10, 1969 U.S. 'Cl. 236--99 2 Claims ABSTRACT OF THE DISCLOSURE A- thermostatically controlled valve for enabling an automatic top burner to operate at an extremely 10W B.t.u. in-put without any risk of extinguishing the ame.

This application is a continuation of Ser. No. 602,285, filed Dec. 16, 1966, now abandoned'.

Background Is that of a gas burning stove wherein flow of gas to the top burners is automatically increased, or decreased, or temporarily shut off altogether, in response to the temperature of the utensil which contains the food to be cooked. Moderate down-throttling, that is, non-radical reduction of the ow of gas poses no problem because the -velocity of the gas entering the venturi of the burner remains high enough to entrain the required air, and the flame, although reduced, remains hard and stable. But reduction of the gas input to a value of the order of 50() B.t.u. which produces the desired low temperature produces 1an unstable llame which may be extinguished by slight atmospheric disturbances. This is due to the fact that, when the gas ow is reduced to about 500 B.t.u. per hour, the pressure under which gas is delivered to the burner venturi drops from about 4 inches of water which is the average normal pressure in the gas main, to about .04. At this pressure, the gas velocity is so low that it cannot entrain t-he required combustion air and the flame may be extinguished. It is in recognition of this danger that the American Gas Association has ruled that the smallest ilame of an automatic burner must be able to withstand a three-mile-an-hour air current. To limit the down-throttling to insure a hard and stable flame, is to limit the benefits which the cycling is intended to vouchsafe.

The prior art Thel invention Resides in providing means for reducing the volume of gas delivered to the burner to about 500 B.t.u. per hour without materially reducing the pressure and velocity at which the gas is delivered.

The drawings In the drawings, FIG. 1 is a vertical, sectional view of a thermostatically-controlled valve embodying this invention, the valve being adapted for use in the bypass type of burner, and being shown in full open position.

FIG. 2 is similar to FIG. 1 but shows the valve in full, closed position.

FIG. 3 is similar to FIG. 1, and shows the valve Iadapted for converting a tower type of burner to the by-pass type.

Description of a conventional by-pass" type valve A conventional by-pass type valve includes a casing 14 lwhich is internally divided to form compartments 12, 16, and 32, and is provided with a conventional disc valve .18 which controls the flow of gas from compartment 12 to compartment 16, and with orice 22 which is adjusted by screw 23 for controlling the flow of gas from compartment 16 to compartment 32, and with valve 36 which controls passage 30 to regulate the flow of gas from compartment 16 to compartment 32. Compartment 32 has an orice 34 which discharges the gas into end 44 of a conventional venturi which leads to burner 20. Valve 36 is pivotally mounted on one end of arm 38, the other end of which is hinged to the bottom wall of casing 14. Arm 38y is moved to the left, or right, as viewed in FIG, l rby the expansion, or contraction, of a bellows 40' in respose to the expansion and contraction of a iluid in a conventional sensing device 42, which has following contact with the bottom of the utensil and which is connected to the bellows by tube 43. Compartment 12 receives gas directly from gas main 10 at the normal pressure of about 4 inches of water.

Description of the operation of a conventional by-pass valve A conventional valve of the type described, operates as follows. The fmain valve 18 is opened to admit gas from the main 10 to compartment 12 and a conventional thermostat, not shown, is set to the temperature it is desired to maintain. As the temperature rises, valve 36 progressively throttles down passage 30, and vice versa. It lwill be appreciated that, as long as valve '36 is open enough to maintain a substantial flame, there is no problem. But, when passage 30 is completely closed, the burner will be supplied by orice 22 only and the small amount of gas entering chamber 32 undergoes a reduction in pressure from about 4 inches to a fraction of one inch. The velocity of gas entering the venturi will also be so reduced that insucient combustion air is entrained and the burner flame will be weak and subject to extinguishment.

Description of one preferred em bodment To overcome the diiculties set forth, I provide tting 24, one end of which is enlarged to form a plenum 25 which receives gas from orifice 22 and the other end of which is in the form of a narrow tube 26 which terminates immediately adjacent discharge orifice 34. In other respects, the valve structure may be as shown in FIG. 1.

Operation of the said one preferred embodiment Once screw 23 has been set, it is left undisturbed, and gas will ilow into compartment 32 through orilice 27 and through opening 30. It will be noted that with valve 18 open, the pressure in plenum 25 will be about the same as in Imain 10 and that restriction tube 26, if anything, increases the velocity of the gas llowing therethrough, so .that the gas flow-ing from orifice 2'7 will ow out of oriice 34 and into the burner venturi at a velocity suicient to entr-ain the combustion air needed to produce a stable -ame which can withstand the three-miles-an-hour wind test.

Description of a conventional tower type burner A tower type burner includes a spot burner, not shown, which is located adjacent burner 20, and is connected to compartment 16 `by tube 43 so as to be supplied with full pressure gas at all times.

Description of rz second preferred embodiment According to my invention, I eliminate the spot burner and I introduce one end of a tube 46 into compartment 16 with the end 27 thereof, adjacent oriiice 34'. By this arrangement, tube 46 discharges gas into orice 34 at substantially gas main pressure in the same manner as the gas is discharged through orifice 27 in the embodiment of F IG. l.

A working prototype was built and proved -to be entirely successful in that the iiame withstood the threemiles-an-hour test even when the gas input was reduced to about 500 B.t.u. per hour.

What is claimed is:

1. A valve mechanism for controlling the ow of gas to a burner, said mechanism including:

a casing,

means dividing the interior of said casing to form a first compartment and a second compartment,

supply means for supplying said iirst compartment with said gas at a pre-determined pressure and in a relatively large volume,

a thermostatically controlled valve having a passage for passing said gas in variable Volume from said first to said second compantment,

the volumetric capacity of said second compartment being so related to the flow capacity of said passage that restriction of said passage causes a corresponding reduction in the gas pressure in said second compartment,

said second compartment having an end member provided with a discharge orifice for delivering said gas from the second compartment to the burner, and

a wholly separate and independently adjustable auxiliary supply means located within said casing for delivering said gas in a fixed, greatly reduced volume from said tirst compartment through said orifice, said auxiliary supply means comprising an .elongated conduit having a irst end terminating in coaxial alignment with said discharge orifice, the opposite end of the conduit communicating with said lirst compartment, the conduit providing means for delivering said gas through the discharge orifice from the first compartment at increased velocity and without interference, said first end of the conduit being spaced slightly inwardly from said end member of the second compartment and from said discharge orifice to permit discharge of gas introduced into the second compartment via said valve.

2. A valve mechanism as set forth in claim l having a nonthermostatically controlled valve between said rst compartment yand said conduit for controlling the iiow of gas to said conduit.

References Cited UNITED STATES PATENTS 1,536,630 5/1925 Reinecke 158-120 1,838,903 l2/1931 Buschow 158-118 X 2,280,739 4/1942 Ball 236-1 FREDERICK L. MATTESON, JR., Primary Examiner.

HARRY B. RAMEY, Assistant Examiner.

U.S. Cl. XR. 431-354

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