US1699297A - Device for controlling fuel supply to gas-burner pilots - Google Patents

Description

Jan. `15, 1929. 1,699,297

E. E. LEDBETTER DEVCE FOR CONTROLLING FUEL SUPPLY TO GAS BURNER PILOTS Filed May 51, 1927 E je 3 1o 11 /I l attenua, 15

Patented Jan. 15, 1929.

UNITED STATI-:s PATENT oFFlcE.

ELMER E. LED'BETTER, OF DETROIT, MICHIGAN, ASSIGNOR TO EVERHOT HEATER COM- CPAN Y, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

DEVICE FOR CONTROLLIN G FUEL SUPPLY TO GAS-BURNER PILOTS.

Application filed May 31, 1927. Serial No. 195,497.

The invention relates to devices for maintaining a pilot light in gas burners and the like, and the principal object is to provide a device capable of restricting the amount of fuel admitted to the pilot light to only that amount necessary to maintain a proper flame without so reducing the size of the regulating openings as to render the same likely to be clogged by impurities in. the fuel line. Another object is to provide improved means for varying the amount of fuel delivered to a pilot light without varying the size of the supply orifices.

The invention is particularly applicable to thermostatically operated gas burners such as are used in hot water heaters, gas ovens and the like, though its use is not necessarily restricted to such devices.

In the present state of the art there are numerous types of heating apparatus operated by gaseousffuel, wherein it is necessary to continuously maintain a pilot light 1n order that the main burner may be operated intermittently. In order to conserve fuel it is desirable to supply to the pilot light the minimum amount of fuel that will insure continuous operation without danger of eX tinguishment. The amount of fuelrequired is exceedingly small, and when it is obtained from a gas supply conduit having a pressure and capacity -for also supplying the main burner, it is necessary to provide a restricted orifice of very small dimensions to prevent an over supply to the pilot light. With such a construction any slight impurities in the gas line may become lodged in the small calibrated orifice and clog the same, thereby reducing the size of the flame to the point where it is readily extinguished. or even stopping the supply entirely. The disadvantages of the use of a single calibrated orificel are -more pronounced with higher pressures in the supply line since the higher the pressure is, the smaller the orice must be to obtain a tiny pilot light.

My invention eliminates the undesirable features mentioned above by employing a regulatingI device wherein the calibrated orifices are made much larger than would be necessary if a single oriiice were used, and arranging a plurality of such Y orifices in series so that the restriction to the flow is obtained by passing the gas through a series of restricted ports. In this manner the supply to the pilot light can be cut down to `the desired amount vwithout increasing the tendency to clog.

My invention may be embodied in various structures, but by way of illustration I have shown in lthe accompanying drawings one particularly advantageous arrangement. In the drawings;

Figure 1 represents a thermostatically operated valve provided with my invention.

Figure 2 is an enlarged axial section through the pilot light regulating device.

In Figure 1 there is represented a thermostatically operated valve of a type adapted to be usedvin a hot water heater of the storage type. l represents a valve housing having an inlet or supply conduit 2, and an outlet or delivery conduit 3, the latter leading to a suitable burner 4. 5 is a disc valve pivotally supported from a lever 6, which in turn is actuated by a thermostat 7. The burner 4 is, in the present instance, of the modified bunsen burner type adapted to be operated from a tiny pilot light to a strong flame depending upon the position of the disc Valve relative to its seat 8. lVhen the valve 5 is entirely closed the fuel for maintaining a pilot light is obtained by bypassing the same through the valve dise, and my invention resides in this part of the apparatus.

As shown in the enlarged view in Figure 2 the disc valve 5 has an opening 9 in the upper face thereof extending part-way through the disc, leaving arelatively thin wall 10. This wall is drilled through at 11 forming a calibrated orifice of circular cross section, the diameter of which is larger than required to limit the gas supply to the pilot light. Inserted in the bore 9 is a cap 12, the lower portion 13 of which is of a diameter to form a tight fit with the walls vof the aperture 9. The upper end of the cap is of slightly reduced diameter, as indicated at 14, and is provided with a head 15. The enlarged portion 12 of the cap is recessed at 16 to provide an inner diameter of the same size as the outer diameter of the reduced portion 14. The reduced portion 14 has within the same a recess 17 forming the interior chamber 18. 12a is a similar cap, the cross sectional dimensions of which are the same as the corresponding parts in the cap 12. rllhe enlarged end of the cap 12a may therefore be engaged with the reduced end of the cap 12, thereby forming the enclosed chamberla. By adding additional caps the assembled structure may be built up to the desired length, forming a series of enclosed chambers With the heads or partitions interposed therebetween. The cap 12 has an orifice 19 drilled in the head 15 and the cap 12a has a similar orifice 19a but the orifices in adjacent caps are preferably arranged in offset relation so that their axes ,are not in alignment.' Preferably one cap has the orifice arranged centrally thereof, while the adjacent cap has the orifice located near the outer edge thereof. The orifices 19 and 19a are preferably of the same size as the orifice 11 in the valve disc, all of these orifices being sufficiently large to minimize the likelihood of being clogged by impurities in the -fuel line. f

With the device as above described the amount of fuel permitted to pass to the pilot burner depends upon the number of caps arranged inl series and the sizes of the orifices in the caps.- The principal advantage of this arrangement is that the 'desired restriction to the flovv of gas may be obtained with orifices of considerably larger diameter than are required in the usual constructions having but a single restricted orifice. Thus With my invention the size of the orifice may be determined solely from the stand point of obtaining a passageway that will not be clogged by impurities, and the regu# lation of the flow can be obtained by v employing a sufficient number of caps provided with such orifices.

In order to fully appreciate the practical advantage of my invention, the following comparison is given between a thermostatic device of the type illustrated and a similar device provided with only one calibrated orifice for the pilot light. When employing the single orifice construction in a certain commercial water heater having a continuously operating pilot light it was found that the orifice shouldbe made With a No. 77 drill; )vhen operating on artificial dgas and with a No. 8O `drill when ,operating on natural gas. In both cases sufficient fuel was supplied to the burner to continuously maintain a pilot light provided there was no clogging in the-orifices, and from an economical standpoint it was therefore not desirable to increase the sizes of the orifices with the consequent increased cost in maintaining the pilot light in constant operation. By changing the construction to utilize my inventionit was found that the sizes of the orifices could be increased'to that made with a No. drill by providing three of such orices in series when `operating on artificial gas and four in series when operatiner on natural gas. The amounty of gas supplie to the. pilot light was in each instance substantially the same as that obtained in the corresponding example employing the single calibrated'orifice. Thus with my invention it is possible to obtain the same restriction to the flow of gas Without the disadvantage of the tendency to clog inherent in the construction using the smaller orifices. Since the area of the aperture made with a. No. TO drill is substantially four times the area made with a No. 80 drill, the advantage of my construction Will be readily apparent.

Another advantage of the present invention resides in the fact that a means is provided for adjustably regulating the supply of gas to the pilot light since the flow may be increased or diminished as desired by merely removing or adding caps to the valve disc. A' further advantage obtained by my in vention is that valves manufactured according to production methods are more uniform in their calibration than With the single orifice type. This is due to the fact that a slight variationl in the diameter of a relatively large orifice does not affect the calibration of the device as much as a correspending variation in the size of a smaller orifice. 4

From the above description it Will be apparent that the essential characteristic of my invention is the provision of a series of non-aligned apertures ina series of spaced partitionsT having intermediate the same a series of chambers.` As the gas passes through the series of chambers the pressure in each successive one is reduced belovv that maintained in the supply conduit, with the result that the effective pressure upon the orifice just preceding the discharge conduit is sufficiently lower than that in the supply conduit, so that a discharge orifice of rela tively large diameter delivers no more fiuid therethrough than would a much smaller orifice under the full pressure of the supply conduit. What I claim as my invention is': 1. A device for regulating the gas supply vto a pilot light, comprising means forming a series of chambers interconnected by nonahgned orifices of circular cross section.

2. A device for regulating the gas supply a pilot light, comprising a conduit havlng a series of spaced partitionstherein, forming chambers intermediate the same, said partitions each being provided With a single orifice of circular cross section and the orifices in adjacent partitions being nonaligned.

3. A device for regulating the gas supply to a pilot light, comprising a series of chambers arranged successively and having heads at the opposite end thereof, said heads each having a single orifice therein of circular cross section and of a lsize which in. itself would supply too great a quantity of gas at the pressureA of the supply conduit, the

restricted flow from the device being obtained by the cooperation of the successive or'iices.

4. A device for regulating the gas supply to a pilot light comprising a series ofY telescopically engaged caps, each open at one end and closed at the other end, the closed end of each cap having a single calibrated restricted orifice therein and adjacent caps having the apertures offset.

5. A device for regulating the gas supply to a .pilot light, comprising a passage-v way having a series of spaced partitions therein, each provided with a single orifice, the axis of which is offset from the adjacent orifice. l

6. A fuel regulating device comprising a cap, a 'second cap telescopically engaging the irsteach cap comprising an external portion adapted to fit within a recess of the adjacent cap and having a single aperture therethrough, the apertures in adjacent caps being in non-alignment.

7. In a device for regulating the gas supply toa pilot light, a tubular member having a-series of transverse partitions therein adapted under the ull supply pressure to deliver too lar e a quantity of fuel for a pilot light, said passageway including a suiiicient number of said apertured partitions to'restrict the flow to theamount required for pilot light.

9. In a fuel regulating device comprising a passageway, having a series of spaced partitions therein formin a series of chambers, each partition belng provided with a single aperture of circular cross section, said passageway including a sufficient number oi said apertured partitions to restrict the flow to an amount required for a pilot light.

In testimony whereof I ailix my signature.

ELMER E. LEDBETTER.

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