US3439161A - Heater - Google Patents

Description

A ril 15, 1969 1.. A. MCELWEE E AL HEATER Filed Sept. 16, 1966 Sheet of 2- NW M, MMN

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HEATER Filed Sept. 16, 1966 Sheet 13 of 2 law/n /4. Mcf/n ee Pay 5. (arc/ray Gearyecfreene, (fr.

INVENTORS BY mm A rrol? E K) United States Patent 3,439,161 HEATER Lorin A. McElwee, Roy E. Cordray, and George .I.

Greene, Jr., Shreveport, La., assignors to UGC Instruments, Inc., Houston, Tex., a corporation of Delaware Filed Sept. 16, 1966, Ser. No. 579,926 Int. Cl. Etllb 7/24 US. Cl. 246428 18 Claims ABSTRACT OF THE DISCLOSURE The present invention is directed to an improved heater and particularly a heater for a railroad track switch.

The presence of ice or snow may render a railroad track switch inoperative. Present day operations of the railroads require that track switches be remotely operated from a central location. To assure that such switches remain operative, heaters have been installed to melt any ice and snow accumulations at the switch. Such prior heaters have been remotely operated, but very considerable difficulties have been encountered with them. Many times the combustion in such heaters has been extinguished by the passing of a train or by wind. Such heaters have overheated certain portions of the switch rails while failing to completely clear the switch of ice or snow. Other difficulties such as improper ignition or failure of ignition and burning of the rail ties have been encountered.

It is therefore one object of the present invention to provide an improved heater for a railroad track switch which is not extinguished by wind or passing trains.

Another object is to provide an improved heater for a railroad track switch which uniformly heats the outside rails and also conducts heat to the space between the rails along the length of the switch.

A further object is to provide an improved heater for a railroad track switch which is actuated responsive to snow or icing conditions.

Still another object is to provide an improved burner and ignition system for a heater having a burning of the fuel along a substantial length of the heater to provide uniform heating along the length of the heater.

A still further object is to provide an improved burner and ignition system for a rail switch heater which does not require premixing of air and fuel and which has a central ignition point with combustion taking place along a substantial length of the burner.

Another object is to provide an improved rail switch track heater which eliminates the aforementioned difficulties, is easily constructed and is readily installed to heat a track switch.

These and other objects and the attendant advantages of the present invention will be more fully understood from the following detailed description and the accompanying drawings wherein:

FIGURE 1 is a plan view of a railroad track switch having the improved heater of the present invention installed thereon;

FIGURE 2 is a detail sectional view of the ignition system and the primary burner tubes;

FIGURE 3 is a sectional view of the ignition trough taken along line 3-3 in FIGURE 2;

FIGURE 4 is a sectional view of the heater, also show- 3,439,161 Patented Apr. 15, 1969 ing the rail, a portion of a tie and the ballast, taken along line 4-4 in FIGURE 1;

FIGURE 5 is a sectional view of the heater only taken along line 55 in FIGURE 1;

FIGURE 6 is another sectional view of the heater taken along line 66 in FIGURE 1;

FIGURE 7 is another sectional view of the heater taken along line 7-7 in FIGURE 1 and FIGURE 8 is a schematic view of the burner tubes to illustrate the combustion of the fuel gas in relation to the burner tubes.

In FIGURE 1, a typical rail track switch is shown including the main rails 10 and 12 and the movable switching rails 14 and 16, with the heater of the invention installed in two sections, section 18 against the outside of rail 10 and section 20 against the outside of rail 12. As is normal, the rails 10 and 12 are supported on ties 22, and suitable structure (not shown) is provided to support and move the switching rails 14 and 16.

The heater sections 18 and 20 are identical and are positioned as stated on the outside of the tracks 10 and 12 to heat the tracks and also to conduct hot combustion gases under the tracks, as hereinafter more fully explained, to melt all snow and ice from between the switch rails and the main rails, thereby assuring that the switching mechanism will not be rendered inoperative by a collection of snow or ice. Fuel gas is delivered from a suitable source of supply (not shown) through the fuel gas supply line 24 through a shutoff valve 26, a temperature control valve 28, to a fuel gas manifold 30. The manifold 30 delivers fuel to the fuel inlet line 32 to supply fuel to the heater section 18 and to the fuel inlet line 34 to supply fuel to the heater section 20.

The valves 26 and 28 are controlled by the control panel 36. Suitable source of electrical current is conducted to the panel 36 through the leads 38 and connection is provided to the control panel 36 from the central control location (not shown) by the leads 40. A means for sensing snow or icing conditions, such as, the snow detector 42, which is connected to the ambient temperature sensor 44, provides an output signal to the control. panel 36 to start operation of the heater whenever snow or icing conditions prevail. It is contemplated that the snow detector 42 may be similar to the device disclosed in the George J. Greene, Jr. application Ser. No. 508,915, filed Nov. 22, 1965. Rail temperature sensor 46 is also connected to the control panel 36 to provide an indication of the temperature of the rails which indication may be used to control the temperature control valve 28 such that when the rails are sufiiciently heated assuring proper operation of the switch, the heater may be shut off. The control panel 36 therefore starts the heater by opening the valves 26 and 28 and by providing suitable power for ignition through the leads 48 to the ignition system responsive to the snow detector 42 and the temperature sensor 44, or responsive to a remote signal through leads 40 to the control panel 36. The control panel 36 also may provide an indication of burning in the heater sections to the central control station through the leads 40. A remote control, such as is shown in the W. McKean White, Jr., Patent No. 2,644,657 issued July 7, 1953, is suitable for opertion of the heater with provision made for the operation of the snow detector 42.

In FIGURE 2, the main portion of a burner and the ignition system for one of the heater sections are illustrated. The fuel gas is conducted to the burner tube through the fuel inlet 34, assuming that FIGURE 2 illustrates heater section 20. The inlet 34 extends through the trough 50 with communication to the trough provided by the orifices 52 and also connects to the fitting 54. The main burner tubes 56 and 58 are connected in axial alignment with each other to the fitting 54. The fitting 54 provides restricted passageways connecting from the inlet 34 to direct the fuel gas into the interior of each of the burner tubes 56 and 58. Each of the burner tubes at its end near its connection to the fitting 54 is provided with a plurality of apertures 60 through which primary air for combustion flows into the burner tubes 56 and 58. The passageways in fitting 54 are substantially restricted so that the fuel gas will be injected into the interior of the burner tubes at a velocity sufficient to draw enough air into tubes 56 and 58 to support burning of less than all of the fuel gas. The fuel and air mixture within the burner tubes 56 and 58 is ignited by the flame within the trough 50 through the apertures 60 which register with the trough 50.

The ignition system which provides both ignition and a pilot light for the burner includes the trough 50 having sparking means, such as the spark plug 62, and the thermal sensor 64 positioned therein. As shown in FIG- URE 2, the right end of the trough 50 is closed up to a point immediately adjacent the burner tube 58 while the left end of the trough 50 is open. The trough 50 includes the bottom 50a and side walls 50b and is mounted under fitting 54 and the apertured ends of main burner tubes 56 and 58.

In operation, the ignition system is supplied with fuel gas from the fuel inlet 34 through a means of directing the fuel gas against the side walls of trough 50, such as the orifices 52. As best seen in FIGURE 3, the orifices 52 are so arranged in relation to the trough 50 so that the gas flowing therethrough impinges on the side walls of the trough at an angle of incidence equal to the angle a and are spaced apart by the angle 12. It has been found in operation that best mixing of fuel gas and air for ignition occurs in the trough 50 when the angle b is approximately 108 and the angle a is approximately 36. With this configuration, the stream of fuel gas impinges on the side walls of the trough 50 at an angle of 36 to create sufficient turbulence for good mixing with the air entering the trough through the opened end and through the spaces above the sides of the trough which are not in direct contact with the burner tubes 56 and 58. It has been found, however, that suitable mixing may be obtained when the angle a varies approximately from 30 to 45. As shown in FIGURE 3, four of the orifices 52 are shown. While tests have indicated that only two such orifices are necessary, each being directed toward the opposite end of the trough from the other, problems may be encountered with only two orifices when particles and impurities in the fuel gas accumulate in the orifices, and therefore four orifices are preferred.

With this structure, fuel gas is supplied to each end of the trough. The turbulence created by its impingement on the side walls causes the fuel gas to mix with air, and allows the spark to ignite this mixture at both ends of trough 50. With ignition achieved within the trough 50 and with the fuel gas flowing into the burner tubes 56 and 58, the flame in trough 50 ignites fuel and air mixture in the burner tubes through those apertures 60 which are in communication with the trough. Also, continued burning in trough 50 provides a pilot flame which re-ignites the main burners in the event of failure of combustion in the main burners.

It should be noted that the ignition system and primary burner tubes do not require any premixing of air with the fuel gas. Further, it should be noted that the size and number of the apertures 60 should be sufficient to provide enough air to the interior of the burner tubes 56 and 58 to support combustion, but should be less than the amount necessary to support complete combustion of the fuel delivered thereto. In general it has been found that suflicient air should be allowed into the main burner tubes 56 and 58 for complete combustion of only one-third of the fuel gas introduced therein.

After combustion has been initiated within the main burner tubes 56 and 58, the combustion gases and unburned gas flow outwardly through each of the burner tubes. As best seen in FIGURE 8, the combustion gases and unburned gas are directed from the main burner tube toward the secondary burner tubes 66 and 68 which have apertures 70 and 72 and are spaced apart from the main burner tubes and from each other to provide additional air to the tubes 66 and 68. The apertures and the spacing of these burner tubes allows a portion of the unburned fuel gas to mix with additional air and burn in the tubes and in the spaces therebetween. The remainder of the combustion gases and fuel gases are conducted through the other burner tubes and combustion is sustained in each tube and at the ends thereof by reason of the additional air being mixed with the unburned fuel gas.

As can be seen from FIGURE 8 the outer ends of each of the main burner tubes 56 and 58 are surrounded by liners 74 and 76, respectively. These liners are substantially the same diameter as the secondary burner tubes 66 and 68. A typical example of an installation would be to utilize oneand one-half inch stainless steel pipe for the main burner tubes having a combined over-all length from the outer ends of the burner tubes of approximately four feet with the outer half of each of the main burner tubes being surrounded by a two and one-half inch stainless steel pipe liner. In such installation it has been found that the restricted passageways in the fitting 54 may vary from 0.046 to 0.086 of an inch and the orifice diameter may vary from 0.013 to 0.018 of an inch depending on the type of fuel gas being used. The larger diameters are generally used for natural gas or methane while the smaller diameters are recommended for use with propane fuel gas. The secondary burner tubes '66 and 68 are approximately four feet long and are of two-and-one-half inch pipe. The spacing between the burner tubes would be approximately four inches and the apertures in the secondary burner tubes are varied in size and number to assure prolonged combustion throughout a substantial portion of the length of the heater.

As can be seen from FIGURES 4 and 5, the liners 74 and 76 surrounding the main burner tubes are supported by clips 78 secured to the housing 80 and the secondary burner tubes are supported by the clips 82 which are secured to the housing 80.

FIGURE 4 is a section through a rail and illustrates the relationship of the heater structure to the ties and ballast. As shown, the housing 80 is positioned to abut against the outside edge of the upper flange of the rail 84, rests on the plate 86 and is held in such position by the bracket 88 which is secured to the tie 22 as by nailing. The plate 86 covers the top surface of the tie 22 to protect it from being overheated. The housing 80 is a sheet metal construction having an upper surface 92 which is generally flat and horizontal in position terminating in the depending flange 94 and a side portion 96 extending from the outer extremity of the upper surface 92 downwardly and terminating in a flange portion 98 which rests on the upper surface of the plate 86 and abuts the clip 88. The clips 78 are suitably secured to the housing 80 as by spot-welding or may be secured thereto by any other suitable means. Separate parts of housing 80 are secured together to provide a continuous housing for the heater sections 18 and 20 in any suitable manner. Generally it is preferred to provide a clip overlying the outer surface of the adjacent edges of separate housings 80 which are suitably held in position by fasteners, such as eyes, which extend through housing 80 and the clip and cotter pins extending through the eyes to secure the adjacent housings together.

As shown in FIGURES 6 and 7, the outermost portions of housing 80 may include simple structure for conducting hot combustion gases outwardly from the burner tubes to the end of the heated section of the rails. FIGURE 6 illustrates housing 80 which includes a panel 100 suitably secured to the housing 80 and which has a configuration to define the passageway 102 with housing 80 and also includes apertures 104 to direct the hot combustion gases against the outside of the rails. The outermost of the heater housings 80 shown in FIGURE 7 is substantially similar to the housing 80 just described in relation to FIGURE 6 and includes similar panel 100 defining the passage 102 with aperture 104. It should be noted however, that this housing 80 includes an end plate 106 and that the panel 100 extends only partially along the length of such housing so that the hot combustion gases at the outer end of the heater section are directed against the outside edge surface of the rails and under the rails between ties to heat the area between the inside of the main rails and the switch rails.

In operation, when the heater sections are ignited, burning proceeds in the main burner tubes 56 and'58, also between the outer ends of the main burner tubes and the secondary burner tubes and the hot combustion gases from burning in the secondary burner tubes 66 and 68 are directed through the areas 102 in the outer sections. The main rails are uniformly heated along the entire length of the track switch. Air which supports combustion is generally drawn through the ballast 108 under the outer edges of the heater sections 80 and through the apertures in and spacing between the secondary burner tubes 66 and 68. However, it should be noted that the housing 80 covering the main burner tubes is provided with slots or apertures along its side 96 to assure that suflicient air is available for the combustion desired in the main burner tubes 56 and 58. With the housings 80 covering and supporting the burner tubes, the rails are heated on their outside surface and also the hot gases pass thereunder, as best shown in FIGURE 4 by the arrows, in the space between the ties to heat the inside portion of the rails and the switch rails thereby assuring that all ice and snow is cleared therefrom so that the switch is operative. Additionally, the housings 80, by providing the covering and the end covers 106, protect the burners from wind. The burners therefore, are not subject to the difficulties encountered by the prior art devices of having wind extinguish combustion.

It has further been found that the particular ignition system of the trough 50, even though combustion fails in one burner tube, re-ignites the burner tube so long as the fuel gas continues to flow. The ignition system, while providing the spark for ignition in only one side of the trough, because of the turbulence created by the impingement of the fuel gas flowing through the orifices 52 against the side walls of the trough 50, assures that fuel is ignited at both ends of the trough 50 and also that the fuel gas in the main burner tubes is ignited through the apertures 60 which are exposed to the trough 50.

So long as fuel gas burns in trough 50, this flame provides a pilot light to re-ignite the main burners. In the event the flames in both the burners and the trough are extinguished, thermal sensor 64 provides an indication of the flame-out and may be used to shut down the flow of fuel gas or to initiate ignition procedures. Also, sensor 64 is connected to controller 36 and may be used as a safety shut down in the event ignition does not occur within a preselected period of time after ignition is initiated.

From the foregoing it can be seen that the heater of the present invention may be actuated by remote control or may be controlled by the local conditions with the snow detector 42 to turn the heater on whenever temperature conditions as sensed by the ambient temperature sensor 44 indicate the likelihood precipitation as sensed by the snow detector 42 is snow or may freeze. The heater then ignites itself and burns unnterrupted providing a uniform heat throughout the length of the track switch to assure that snow and ice, which may collect at the track switch location, are completely melted to thereby render the track switch operative at all times.

This heater, as has been stated, in addition to providing a uniform heating along the entire length of the track switch also is continuous so long as desired since it is not subject to being extinguished by wind or other conditions.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.

What is claimed is: 1. A heater, comprising a plurality of burner tubes, means supporting said burner tubes in substantially axial alignment with an open space between adjacent ends of said burner tube, means supplying fuel to one of said burner tubes, said burner tubes defining apertures for admitting air,

and ignition means associated with said one of said burner tubes, said apertures restricting the amount of air flowing into said burner tubes whereby combusion of fuel occurs along the length and at the spaces between each of said burner tubes. 2. A heater according to claim 1, wherein said support means includes a housing partially surrounding said burner tubes and directing hot combustion gases in a direction away from said burner tubes. 3. A heater according to claim 1, wherein said ignition means, includes an ignition trough positioned in close spaced relationship to said one burner tube and open to some of the apertures in said one burner tube, means supplying fuel to said ignition trough, and spark means in said trough to ignite fuel in the trough whereby combustion in the trough ignites fuel in said one burner tube. 4. A heater according to claim 3, including means directing fuel against said ignition trough at an angle to produce sufficient mixing of fuel and air for ignition by said spark means. 5. A heater according to claim 4, wherein the angle of incidence of said fuel against said trough is between 30 and 45 degrees. 6. A heater according to claim 4, wherein the angle of incidence of said fuel aganst said trough is approximately 36 degrees. 7. A heater for a railroad track switch, comprising a plurality of burner tubes, means supporting said burner tubes in substantially axial alignment and in heating relationship along the length of one of the rails of the track switch, said burner tubes each being spaced apart at their ends from the end of the adjacent burner tube, means supplying fuel to one of said burner tubes, apertures in said one burner tube for admitting sufficient air for only partial combustion of the fuel supplied to said one burner tube, ignition means associated with said one burner tube,

and means directing fuel from said fuel supply means longitudinally into said one burner tube whereby unburned fuel and hot combustion gases flow through said burner tubes and a portion of the unburned fuel is burned in the spaces between and in each of the burner tubes. 8. A heater according to claim 7, wherein said one burner tube is between other burner tubes and fuel is delivered to a second burner tube adjacent said one burner tube and including, means directing fuel from said fuel supply means longitudinally into said second burner tube in a direction away from said one burner tube whereby combustion of fuel proceeds outward through said 14. As a subcombination with a heater having a burner burner tubes in opposite directions. 9. A heater according to claim 7, wherein tube with apertures defined in the wall of the burner tube near the point of introduction of fuel, an ignition system,

said supporting means includes a housing mounted on comprising the rail ties and covering the side of said burner a trough, tubes away from said rail and extending over the said trough having its open side in communication with top of said tubes into engagement with the side of at least one of said apertures in said burner tube, said rail to direct hot combustion gases toward said spark means in said trough, and rail and under said rail between ties. fuel gas supply means directing fule gas at an angle 10. A heater for a railroad track switch having a pair 10 toward at least one wall of said trough, of main rails and switch rails, comprising the angle of incidence of said fuel gas with said trough a pair of heater sections, wall being preselected to create sufficient turbulent each heater section being mounted along the outside fiow of fuel gas and air in said trough to provide a of one of said main rails and including, combustible mixture thereof. a plurality of burner tubes, 15. A subcombination acording to claim '14, wherein means supporting said burner tubes in substantial axial said angle of incidence of fuel gas with said trough wall alignment and in heating relationship along the length is between 30 to 45 degrees. of one of the rails of the track switch, 16. A subcombination according to claim 14, wherein said burner tubes each being spaced apart at their ends said angle of incidence of fuel gas with said trough wall from the end of the adjacent burner tube, is approximately 36 degrees. means supplying fuel to one of said burner tubes, 17. As a subcombination with a heater having a burner apertures in said one burner tube for admitting air for tube with apertures defined in the wall of the burner tube only partial combustion of the fuel supplied to said and a fuel gas supply line connecting to said burner tube one burner, near said apertures of an ignition system, comprising ignition means associated with said one burner tube, a trough having a bottom and opposing side walls,

and said trough positioned with said bottom facing said means directing fuel from said fuel supply means apertures in said burner tube and said fuel gas suplongitudinally into said one burner tube whereby ply line extending through said trough, unburned fuel and hot combustion gases flow through said fuel gas supply line defining at least one orifice for said burner tubes and a portion of the unburned fuel directing fuel gas into said trough at an angle with is burned in the spaces between and in each of the at least one of said side walls whereby said fiow of burner tubes. fuel gas is sutficiently turbulent to mix with air to 11. A heater according to claim 10, wherein provide a combustible mixture, and said one burner tube is between other burner tubes and means associated with said trough for igniting said fuel is delivered to a second burner tube adjacent said combustible mixture. one burner tube and including 18. A subcombination according to claim 17, including means directing fuel from said fuel supply means longimeans mounted in the trough to sense combustion tudinally into'said second burner tube in a direction therein. away from said one burner tube whereby combustion of fuel proceeds outward through said burner tubes 40 Ref renc s Cited i p g 1 10 h UNITED STATES PATENTS ea er accor ing to c aim w erem said supporting means includes a housing mounted on 2 3 3 2 11/1905 Younlg 2646*428 the rail ties and covering the side of said burner tubes 7 3/1940 Krog et a 12 271'2 away from said rail and extending over the top of 2633190 3/1953 i et a1 1262712 said tubes into engagement with the side of said 7/1953 White 246*428 rail to direct hot combustion gases toward said rail 2960983 11/1960 126 271'2 and under said rail between ties. 3204094 8/1965 Hulsmga 246428 ARTHUR L. LAPOINT, Primary Examiner.

RICHARD A. BERTSCH, Assistant Examiner.

US. Cl. X.R.

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