US 1281300 A
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Description (OCR text may contain errors)
C. N. CROSS.
APPLICATION FILED SEPL 13, m1
Patented Oct. 15 1918.
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CHARLES N. CROSS, 0F STANFORD UNIVERSITY, CALIFORNIA.
Specification of Letters Patent.
Patented Oct. 15, 191's.
Application filed September 13, 1917. Serial No. 191,163.
To all whom it may concern:
Be it known that 1, CHARLES N. Gross, a citizen of the United States, and a resident of Leland Stanford, Junior, University, Stanford University, county of Santa Clara, and State of California, have invented a new and useful Gas-Burner, of which the following is a specification.
My invention relates to gas burners and particularly to gas burners in which the pro portions of gas and air are automatically determined.
An object of my invention is to provide a burner with which combustion is practically perfect and the flame temperature, or temperature-head, is at the maximum for the given flow and pressure of the gas consumed.
Another object of my invention is to pro vide a burner in which the volume of air admitted to mix with the gas is regulated automatically to correspond with the volume and pressure of gas admitted into the burner.
It has been determined by experiment that the rate of heat-flow from hot gases in close thermal contact with water is nearly proportional to the fourth root of the temperature-head, when the difference in temperature between the gases and the water is in the neighborhood of 2000 Fahrenheit. It has further been determined that the index of the root decreases as the temperature-difference increases; and that the index also 'decreases as the velocity of the hot gases over the heating surfaces increases. Hence, for the maximum heat-flow per unit of heating area, a high temperature-difference and a high velocity of gases over the heating surface is essential; and it is, therefore,
broadly the object of my present invention to provide a burner in which these conditions of maximum heat-flow are met.
In the use of the burner shown in Figure 1 of the drawings, for top heating on a domestic gasrange, an efiiciency of 74.8% has been attained. The significance of this will be clear when it is understood that the efficiency of various types of gas burners now in common use varies under laboratory tests from 35 to 15%. The great eificiency of my burner is due to the extremely high temperature-head which it maintains, with the consequent high rate of heat-flow. With gas pressures of 3 to 8" of water, a maximum flame temperature or temperature-head of 2800 degrees to 2900 degrees is obtainable. With gas pressures of 1 to 8 pounds gage,
temperatures up to 3200 degrees are secured.
In the following description of the preferred form of my invention which is illustrated in the drawings accompanying and forming part of the specification, I shall treat my invention as applied in a gas range for domestic uses, but it is to be understood that it may be applied to and adapted for other uses. I do not, therefore, limit myself to the showing made by. the said drawings cal section.
Fig. 2 is a plan view of the burner shown in Fig. 1.
Fig. 3 is a plan view of a modified form of grid which may be used with my burner.
Fig. 4 is an elevation of a modified form of burner.
Fig-5 is a sectional view taken on the lin 5- 5, of Fig. 1.
The gas burner of my invention consists of a fixed base 6 of cylindrical form adapted to be threaded tightly upon the nipple 7 which is the terminal fitting on the pipe 8 through which gas is conducted to the burner. A hexagonal boss 9 is provided on the bottom of the base to serve as a wrench hold. The base is formed with a chamber 12 into which gas from the nipple 7 discharges, and the upper wall 13 is provided with a centrally-disposed conical aperture which forms the seat of the valve controlling the passage of gas from the chamber 12 into the burner.
Fitted snugly about the cylindrical base is the lower end of the burner tube 14. The tube is rotatable upon the base and is provided with a helically-disposed thread 16 engaging a corresponding. groove in the base 6, so that rotation of the tube is accompanied by an axial movement thereof away from or toward the base.
Qecured rigidly to the tube and lying across the lower portion thereof just above the top of the base 6 is a plate 17 forming a partition wall in the tube. This plate is provided with a centrally-placed conical needle 18 which projects downwardly from the lower surface of, the. plate and is adapted to seat in the aperture in the upper wall of the base 6. Apertures 19 through the plate 17 at the base of the needle provide passages for the gas into the lower portion of the 5 burner tube when the needle valve is opened.
Closure of the needle valve seals the only egress from the pipe 8 and no leakage of gas can take place around parts, of .the burner. Normally the needle valve is closed when the 10 tube 14 is in the lowermost position onthe base 6, as shown in Fig. 1. Rotation of the tube causes it to recede from the base, .thus raising the needle from its seatand opening the passage. The pitch of the thread 16an'd vmating groove is such that rotation of the tube through an arc of about .60 degrees, .will effect the maximum opening. ofthe needle valve. Preferably a separate valve or cock-21 of any suitable type is provided in zorthe supply pipe22 for controlling the admission of gas into .the pipe 8, and means are preferably provided .for coordinating the operation of the two valvesso that the tube 14 is rotated .to open or close the needle valve simultaneously with the opening or closing of the cock.
.The valve stem 23 is provided with an operating handle 24 with which -it'may be turned to open or close the passage into the pipe 8. Projecting from the side of the stem is a lever arm 25 to which is pivotally attached a link 26. The other end of the-link is pivoted to an arm 27 carried upon the side of the burner tube 14. Movement of the handle 24 to openorclosethe cock 21 is thus accompanied by a corresponding ,rotation andaxial movement of the tube 14,,opening or closing the passage past the needle 18. Preferably the handle 24 is moved through a maximum arc of about 90 and therefore ;.the arm 25 is .made'enough shorter than the arm 27 to cause a movementof about 60 in the latter. Above the plate 17 the tube 14extends in cylindrical form inclosing a mixing chamber 29, then, narrowing into a Venturi tube 31, it flares outwardly toward thetop where a forami-nated block or grid 32 is held upon asuitably formed flange33. Inlet ports 34 are formed in the wall of the tube'for-the admission .of air into the mixing chamber 29. The .function of the Venturitube is to augment the velocity of gases passing the-revthrough, and somewhat in the .manner of an injector, draw into the current of gas, the required volume of air. Preferably means are provided .for automatically regulating the volume of air drawn through .these portsin-accordance with the volume of gas delivered from the needle valve.
A sleeve 35 isrigidly attachedtatheflange .36 on=the lowerportion of the.base, and ,ex- -tends' upwardly about .the cylindrical portion of zthe ftube 14 which incl oseszthe chamber29 forming a sliding fit therewith. Ports 37 aref'ormed in the sleeve which in the position of parts indicated l are out of register with the ports 34 in the tube so that the chamber 29 is closed. With rotation of the tube 14 to admit gas through the needle valve,the ports 84 gradually move intofull register with apertures 37, the amount of openingat alltimesjbeing such as to admit the proper proportion of air. As shown in Fig. 5, I prefer rouse-three ports -34 in the burner tube .andthree ports 37 inthe sleeve,
and to. rotate .the tube through'a maximum arc of about 60fidegrees. owing to the axial ,movementof thev sleeve when it is rotated,
each pair of ports 34 and 13.7 areepreferably .disposed upon a helicalcurve, the pitchoof which is the same aszthe pitch of the thread 16. The size of the needlevalve passage,
the pressureof gas and thesize of the air inlets, are carefully related so; thatthe most perfect combustion and the maximum effi- ..ciency for-the volume of gas vconsumed is obtained.
- The :f'oraminated.blocker grid 32- .has an important influence ,upon the proper functioning of ,my invention. For a burner of the size and proportions shown in Fig. 1,
:I preferto use ,a grid piercedby apertures 38 of squaresection. The section may eonveniently be about .05 on a side. ,One of the functions of the grid is to .produce a short flame and .the maximum temperature is produced,;between .05 and .10 from-the top surface of .thegrid. Because of .this
fact, the utensil'beingheated maybe placed very close to .the grid ,and in the zone of highest temperature Without smothering the flame. In ordinary burners the flame .is smothered by too close a spacingof the utensil. The nearnessoftheutensil to the burner prevents the-admixture ,Of cold air in .the
flame .and materially assists in maintaining the high temperature-head essential-to efli- .cient operation. It should .be ,noted that with a given pressure and volume of gas ameter and thicknessof the grid and .the
shape and. sizeof the. apertures,-therethrough,
the proportionsofthe Venturi t11b e, and the size of theair inlets, .are ,amongthe important factors,,a proper relation ofwhich *From theaboveit will be clearthat rotation ,of the tube '14 lay-movement of the .handle .24 results in admitting gas vunder pressure through the 1 needle valve *1 into i the "mixing chamber, and also simultaneously opens the passages 34%,37 through which air is drawn into .the moving stream of i gas delivered into .the mixing chamber, thedipassing into the Venturi tube. From the Venturi tube, the gas and air mixture is delivered to the grid apertures, above which, upon ignition, it burns with a short, intensely hot flame.
In Fig. 3, I have shown a modification of the grid 32. The top of the burner tube 14 is flared outwardly to hold a grid of much larger diameter than that shown in Fig. 1. The grid consists of a solid or imperforate center 41 about which a band 42 of suitable width and thickness is wound in an involute curve, the coils spaced a short distance apart. The gas passes upwardly out of the burner tube 14 between these coils and burns above the annular gridded space so formed, as already explained. This construction is also adapted for use where it is desirable to distribute the heating flame over a wide area.
In Fig, 4, I have shown a modified form of burner, in which the area of the air inlet. into the mixing chamber is constant instead of variable. The sleeve 34 is omitted in this construction and the four air inlets 43 are so proportioned as to admit the proper volume of air for the gas admitted during normal operation.
Secured rigidly to the tube and lying across the lower portion thereof just above the top of the base 44 is a partition plate 46 which is provided with a centrally-placed conical aperture forming the valve seat for the needle 47 projecting upwardly from the upper surface of the base 44 and preferably formed integrally therewith. Normally the needle valve is not quite closed when the tube 14 is in the lowermost position on the base 44, as shown in Fig, 4. This leaves a passage 48 around the needle suflicient for the gas in the pipe 8, when the cook 21 is closed, to pass into the mixing chamber 29 and thence to the grid where it is consumed before the flame dies out. Then the cock 21 is opened, the accompanying rotation of the tube 14 causes the tube to recede from the base, thus raising the plate 46 from the fixed needle 47 and enlarging the passage 48 suiiiciently to permit the calculated quantity of gas to pass. Otherwise the structure and operation of this burner is the same as that already described in detail.
The line U above the grid 32 in Fig. 1 represents the upper surface of the range grating upon which the utensil to be heated is supported over the burner. It will be understood that the spacing of the grating above the burner is suchthat when the burner is turned on, it rises into the proper position for maximum efliciency.
1. In a gas burner, a chambered base, a burner tube rotatably mounted on said base and arranged to move axially in respect thereof when rotated, an aperture in said base for admitting gas to said burner, a needle movable with said tube for controlling the flow of gas through said aperture, a pipefor supplying gas to said base chamber, a cock in said pipe, and means for effecting the rotation of said tube to operate said needle by the operation of said cock.
2. In a gas burner, a base, a burner tube having air inlet ports therein, rotatably and axially movable on said base, a val e operated by the axial movement of said tube arranged between said tube and said base, and a sleeve fixed to said base and having ports therein with which the ports in said tube are adapted to be registered by the rotatable movement of said tube.
3. In a gas burner, a movably mounted burner tube, means for supplying gas to said tube, a valve operated by the movement of said tube arranged between said tube and said supplying means, a cock for controlling the passage of gas through'said supplying means, and means connecting said tube and said cock whereby the operation of said cock efi ects the valve-operating movement of said tube.
4. In a gas burner, a chambered base, a burner tube movably mounted on said base, a valve operated by the movement of said tube arranged between the tube and said base, air inlet ports controlled by the movement of said tube for admitting air into said tube, means for supplying gas to said chambered base, a cock for controlling the flow of gas through said supply means, and means for coordinating the operation of said cock with the operation of said valve and of said air inlet ports.
5. In a gas burner, an apertured chambered base, means for supplying gas to said base, a burner tube movably threaded upon said base and having a horizontal partition wall adjacent said base, and an apertured needle on said wall adapted to control the passage of gas through the aperture in said base.
6. In a gas burner, an apertured chambered base, means for supplying gas to said base, a burner tube movably threaded upon said base and having an apertured partition wall adjacent said base, a needle on said wall adapted to control the passage of gas through the aperture in said base, means for admitting air into said tube, and a grid comprising a foraniinated block arranged in said tube.
7. In a gas burner, an apertured chambered base, means for supplying gas to said base, a burner tube movably threaded upon said base and having an apertured partition wall adjacent said base, a needle on said wall adapted to control the flow of gas through the aperture in said base, said tube forming a mixing chamber above said wall and being contracted to form a Venturi tube above the mixing chamber. inlet ports for admitting air into said mixing chamber, and a grid comprising a foraminated block arranged at the top of said Venturi tube.
8. In a gas burner, an apertured chambered base, means for supplying gas to said base, a burner tube movably mounted upon said base and having an apertured partition wall adjacent said base, a needle on said wall adapted to control the flow of gas through the aperture in said base when said tube is moved, said tube forming a mixing chamber above said wall and being contracted to form a Venturi tube above the mixing chamber, inlet ports in said tube for admitting air into said mixing chamber, a sleeve fixed on said base surrounding said burner tube and provided with ports with which the ports in said mixing chamber are adapted to be registered when said tube is moved, a foraminated block forming a grid at the top of said burner, and means for moving said burner tube upon said base.
9. In a gas burner, a chambered base, a burner tube movably mounted on said base, a valve operated by the movement of said tube arranged between the tube and said base, air inlet ports controlled by the movement of said tube for admitting air into said tube, means for supplying gas to said chambered base, a cock for controlling the flow of gas through said supply means, means for coordinating the operation of said cock with the operation of said valve and of said air inlet ports and means at the top of said burner tube for producing a plurality of short flames.
10. In a gas burner, an apertured chambered base, means for supplying gas to said base, a Venturi tube arranged on said base,
a plate in said tube movable in respect of said base, an apertured needle through which gas from said chamber passes into said tube, means operative by the movement of said plate for controlling the passage of gas through said needle, and means for admitting air into said tube.
11. In a gas burner, an apertured chambered base, means for supplying gas to said base, a Venturi tube'arranged on said base, a plate in said tube movable in respect of said base, an apertured needle through which gas from said chamber passes into said tube, means operative by the movement of said plate for controlling the passage of gas through said needle, means for controlling the passage of gas through said supply means, and means for coordinating the operation of said gas control means and said movable parts.
12. In a gas burner, a chambered base, means for supplying gas to said base, a Venturi tube having air inlet portstherein and arranged on said base, said base being provided with an aperture through which gas passes from said chamber to said tube, a plate arranged in said tube above said apertured base, means for moving said plate to control. the flow of gas from said chamber, means 'for controlling the passage of gas through said supply means and means for coordinating the operation of said gasv control means and said plate.
In testimony whereof I have hereunto set my hand at San Francisco, California, this 8th day of September, 1917. 7
CHARLES n. onoss.
In presence of- G. S. EVANS.
Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of, Patents,
Washington, D. G.