US2186474A - Furnace - Google Patents

Description

Jan. 9, 1940. J. BLIZARD 2,186,474

I warmer:

' 7 Filed Nov. 4, 1937 2 Sheets-Sheet 1 Jan. 9, 1940. J. BLIZARD 2,186,474

FURNACE Filed Nov. 4. 1937 2 Sheets-Sheet 2 Patented Jan. 9, 1940 burrs!) 's'rA'n-zs FURNACE John Blisard, Garden City, N. in, as..." to Foster Wheeler Corporation, New York, N. Y., a corporation of New York Application November 4, 1937,.Serial No. 172,670

16 Claims.

My invention relates to furnaces, and more particularly pertains to means for, firing the burners of steam boiler furnaces. The invention is particularly useful in connection with fur- 5 naces in which there are one or more burners mainly for superheating steam in addition to one or more burners for generating steam, the two sets of burner'sbeing separated by groups of superheater tubes, boiler tubes, baiiies or the like,

10 with the arrangement such that the firing and operation of the primary burner or burners will not in itself ignite the secondary burner or burners but the invention is not limited in its application to this particular arrangement. My in-' 15 vention also has application to steam boilers that are wholly or partially surrounded by an air duct or air chamber, the pressure in which is normally considerably higher than that in the boiler room or firing isle, although the invention 20 is not so limited.

Various .means might readily be provided for the entrance of a firing torch through an ordinary ignition port in the furnace wall to a second'ary set of burners, were it not for the fact 25 that, after the main or primary burners are in operation, the pressure of the combustion gases within the furnace will be sufllcient to cause a blast of gas from the furnace to pass outwards through the aperture through which the torch is 30 introduced, and to extinguish the torch and cause possible serious injury to the operating personnel, unless special means are provided to prevent such results.

The present invention provides means whereby 85 one or more burners, or a secondary set of burners, may be safely and readily ignited in steam boiler furnaces, or other types of furnaces.

For a better understanding of the particular features that characterize my invention, refer- 40 ence may be had to the following description considered in connection with the accompanying drawings, forming a part thereof and in which:

Fig. 1 is a more or less diagrammatic vertical sectional view of a steam boiler and. furnace 5 therefor, having primary and secondary sets of fuel burners in the front wall of the furnace, showing the location therein adjacent the secondary burners. of burner ignition means embodying the invention;

Fig. 2 is a longitudinal sectional view of the ignition means taken on lines 2-2 of Figs. 1 and 4;

Fig; 3 is an elevational view of the outer end 55 of the apparatm;

Fig. 4 is a transversesectional view taken line 4-4 of Fig. 2, and

Figs. 5, 6 and 7 are diagrammatic views illustrating three diiferent positions of the movable parts of the apparatus during various stages of its operation.

Like reference characters refer'to the same parts throughout the several views.

Referring to the drawings particularly Fig. 1, reference character Ill designates the setting of 10 a steam boiler in which a steam and water drum H is connected to lower drum [2 by-a bank of steam generating tubes l3, and to lower drum It by another bank or group of steam generating tubes i5. Aconduit it connects the steam space of the drum I l with a superheater inlet header ll which serves a plurality of bent superheater tubes I8, the outlet ends thereof being connected to an outlet header l9. Two spaced sets of fuel burners and 2|, positioned in the front wall 20 22 of the boiler setting, supply the products of combustion required respectively, in the normal operation of the boiler, for generating and superheating the steam. The furnace gases, after being partially cooled by their passage over the steam generating and superheating tubes, enter the flue or uptake 23 in which may be located an economizer 24 or other heat recovery apparatus. Adjacent one or more of'the bumers 2! is an aperture 25 in the furnace wall through which, by

' means of the present invention, a firing torch can be passed, and the burners 2| safely and readily ignited.

Referring now to Figs. 2 to 7 inclusive, an air duct 26 is provided between the furnace wall and an outer casing wall 21 in which a polygonal opening 28 is partially closed by a cover plate 28, which is firmly secured to the casing wall by the machined'screws 30 and nuts 3|, the joint between said cover plate and easing wall being made pressure tight by means of a brass packing strip or gasket 32. In the central portion of the cover plate is a round aperture 33 that can be closed by a flap cover 34 pivoted on stud 35. When moved to closed position by handle 31, the

' notched portion 38 of the fiap cover engages the I or other suitable means.

heat resisting metal.

43 which is secured by tap bolts 44 to the cover plate, and at the inner end by a bracket 45 which .is secured to the casing 42 by stud bolts 46. A

shaft 41 having at the outer end a fixed crank 48 and handle 49 extends from in front of the air duct wall, through the cover plate and the air duct in a direction parallel to the ignition tube 4| to a point adjacent the inner end thereof. This shaft is also supported by the brackets 43 and 45 through which it passes. shaft is prevented by collars 50 and which are held in a fixed position on the shaft by set screws At the point where the shaft passes through the cover plate, a pressure tight seal is obtained by packing material 52 which is held firmly in place by a cylindrical housing 53, welded to the outer surface of the cover plate, and by a cap 54 which is threaded over the housing. It will be understood that owing to the pressure in the air duct all joints in the outer casing wall must be of sufiicient pressure tightness to prevent leakage.

Rigidly fixed to the inner end of the shaft 41,

for rotation in the narrow space 55 between the furnace wall casing 42 and the inner end of the ignition tube 4|, is a relatively wide triangular shaped shutter 56 made of a high temperature A guard plate or guide 51 for this shutter, is welded to the lower portion of the ignition tube adjacent its inner end. Welded or otherwise fixed to the outer end of the ignition tube is a segmental plate 58 that partially weight 6| so disposed as to tend to close the shutter by gravity. Fixed to the shaft at a point adjacent the outer shutter 60 is a lug 52 having a recess 63, and fixed to the shutter 60 is a lug 64 which is received in the recess 83 of the lug 62, the arrangement being such that when the shaft is rotated the shutter 60 is moved so as to open or close the outer end of the ignition tube. A guard plate or guide 65 for the shutter 60, is welded to the upper portion of the outer end of the ignition tube. It will be noted that when the outer shutter is in a closed position, as shown for example in Fig. 3, the notch 50' coincides with the notch 59 in segmental plate 58 thus forming a small aperture for receiving and supporting a firing rod 66, one end of which is adapted to carry a torch 61.

The operation of the described embodiment of my invention is as follows:

When it is desired to light the burners 2|, the wing nut '40 on stud 39 is turned soas to free the flap cover 34 which is then lowered to the open position shown clearly in Figs. 2 and 3. By means of the handle 49, the crank 48 and the shaft 41 are rotated to the right or in a counterclockwise direction from the position shown in Fig. 5 to that shown in Fig. 6. It will be perceived that a shoulder of lug 62 acting against the lug 64 will have fully opened the shutter 60, which has been brought to a stop by contact with the casing wall, while the larger inner shutter 56 has rotated a certain distance withoutopening Axial movement of the 62 on lug 64 will be temporarily released and the shutter 60 will normally fall by gravity, due to the weight 6|, to a closed position against segmental plate 58, and the shutter 55 will merely have rotated back to the position shown clearly 5 in Fig. 5. However, by continuing the clockwise movement of the crank for approximately 45 to the position shown in Fig. 7, the shutter 56 will rotate far enough to fully open aperture 25. The firing rod 65 and lighted torch 61 can then be safely introduced through the aperture 25 into the furnace chamber and the burners 2| will be readily lighted, the outer shutter remaining closed. With proper design and relationship of the several parts, the upper shoulder of lug 62, as seen in Figs. 5 and 6, will engag lug 64,

if shutter 50 has not theretofore fallen to closed position, and force shutter 50 to closed position before inner shutter 55 has been moved to open position. The burners having been lighted, the operation just described is reversed to remove the firing rod.

It is apparent that my invention provides improved ignition means, specifically of the air lock type, whereby one or more burners, or any secondary or additional set of burners under the conditions referred to, can be readily ignited without the risk of "a blast of hot furnace gases extinguishing the torch, or entering the firing isle, boiler room, or other furnace inclosure regardless of the pressure in the furnace chamber. And, it is to be understood, that although I have herein described and illustrated a preferred embodiment of my invention applied to a furnace wholly or partially surrounded by an air duct, the latter may be omitted, and other changes or modifications made in the present disclosure without departing from the principles of the invention, which is not to be limited except by the scope of the appended claims.

What I claim is:

1. A furnace having a primary burner and a secondary burner so disposed with respect to the primary burner that operation of the latter will not ordinarily fire the second burner, means providing a chamber having communication with the furnace adjacent the secondary -burner through which a torch may be passed to fire the secondary burner, a shutter at theinner and outer end portions of the chamber for controlling fluid flow through the chamber, and means for operating the. shutters to permit the entry of the torch into the chamber and the furnace and to prevent a fiow of gases and air therethrough sufiicient to extinguish the torch when the torch is in the chamber.

2. A furnace having a primary burner and a secondary burner so disposed with respect to the primary burner that operation of the latter will not ordinarily fire the secondary burner, means providing a chamber having communication with the furnace adjacent the secondary burner through which a torch may be passed to fire the secondary burner, a shutter at the inner and outer end portions of the chamber for controlling fluid flow through the chamber, and means for operating the shutters to open the outer end of the chamber without opening the inner end to permit the entry of the torch into the chamber, and for closing the outer end and opening the inner end of the chamber to permit the entry of the torch into the furnace. I

3. In a boiler furnace wholly or partially surrounded by an air duct, a primary set of fuel burners for generating steam and a secondary area-r74 set of fuel burners mainly for superheatingsteam disposed so that the operation of the primary burners will notin itself ignite the secondary burners, said last mentioned burners being separated from said primary set of burners by boiler and superheater tubes, means for igniting said secondary set'of burners after said primary burners are in operation comprising an aperture in the boiler furnace wall and an ignition tube in axial alignment with said aperture extending outwardly through said air duct to the outer wall thereof, an inner and outer shutter in said i n tion tube, a notched segmental plate fixed to the outer end of said ignition tube, means for operating the shutters from a point in front of said air lock, and means for controlling the opening and closing of each of said shutters so asto permit a firing rod and torch to be passed through said ignition tube and said aperture and removed therefrom, and at the same time to prevent a blast of hot products of combustion from passing through said ignition tube.

4. In a furnace, a primary set of fuel burners and a secondary set of fuel burners, means for igniting the secondaryburners after the primary burners have been placed in operation comprising an aperture in the furnace wall adjacent said secondaryburners and in axial alignment with an ignition tube, inner and outer shutters in said ignitiontube, a notched segmental plate fixed to the outer end of said ignition tube, and means for alternately opening and closing said shutters in such manner as to permit the entrance of a firing rod and torch through said ignition tube and said aperture and to prevent a blast of hot furnace gases from extinguishing said torch.

5. In a furnace, a plurality of sets of burners, means for igniting one of the sets of burners whileanother of the sets of burners is in operation, comprising anv ignition tube in axial alignment with an aperture in the wall of the furnace adjacent one of said sets of burners, an inner shutter and an outer shutter for the ignition tube, means for operating the shutters so 'as to permit a firing rod and torch to be passed through said ignition tube and said aperture and to prevent a blast of products of combustion from the burners already in operation from extinguishing said torch.

6. In a steam bolier furnace having a plurality of sets of burners, means for igniting one of the sets of burners while another of said sets of .bumers is in operation, comprising a firing tube in axial alignment with an aperture in one of the walls of the furnace, a notched segmental plate fixed to the outer end of the firing tube and partially closing the tube, and inner and outer shutters for said firing tube arranged to be alternately opened and closed to permit the entrance into said furnace of a firing rod and torch andto prevent said torch from being extinguished by a blast of hot furnace gases.

7. In a steam boiler furnace having a plurality of sets of fuel burners, means for igniting one of the sets of burners after another of said sets has been put inoperation, comprising an ignition tube extending outwardly from one of the walls of said furnace in axial alignment with an the arrangement being such that said shutter and said segmental plate together will substantially close the outer end of said firing tube and at the same time provide a small aperture to receive a firing rod, an inner shutter adjacent the inner end of said ignition tube, and means for alternately opening and closing said shutters so as to permit the entrance of a firing rod and torch into said furnace and to prevent a blast of products of combustion from extinguishing said torch and passing through said ignitiontube.

8. A furnace having enclosing walls and at least one burner, one of said walls having an aperture through which a torch may be passed to fire said burner, and valve means for preventing fiuid flow through the aperture after the torchihas been inserted in the aperture.

*9. A furnace having enclosing walls and at least one burner, one -of said walls having an aperture through which a torch may be passed to fire said burner, and spaced valve means for preventing fluid flow through the aperture after the torch has been'inserted in the aperture.

10. A furnace having enclosing walls and at least one burner, one of said walls having an aperture through which a torch may be passed to fire said burner, means providing a chamber having communication with the aperture, and valve means for preventing fluid flow through the aperture and chamber after the torch. has been inserted in the chamber.

11. A furnace having enclosing walls and at least'one burner, one of saidiwalls having an aperture through which a torch may be passed to fire said burner, means providing a chamber having communication with the aperture,-and spaced valve means for preventing fluid flow through the aperture and chamber after the torch'has been inserted in the chamber.

12. A furnace having enclosing walls and at least one burner, one of said walls having an aperture through which a torch'may be passed to fire-said burner, a tubular member in communication with the aperture, spaced shutters and the aperture, and single means operable to move one shutter toopen position while another shutter remains in closed position. v

14.-A furnace having enclosing walls and at least one burner, one of said walls having an I aperture through which a torch may be passed.

to fire said burner, a tubular member in communication with the aperture. spaced shutters for preventing fluid flow through said member and the aperture. a shaft for operating said shutters. and means for operating the shaft,

15. A furnace having enclosing walls and at,

least one burner, one of said walls having an aperture through which a torch may be passtn'l tofir'e said burner, a, ,tulmlar member in comm'unication with the aperture, spaced shutters for preventing fiuid "flow through said member 'and'the aperture, a shaft, one shutter being fixed to the shaft, another shutter being operable .by

the shaft ins uch manner that it may be moved ato open position while said one shutter continues to prevent fluid flow through the tubular memand means for moving the outer shutter to open her, and means for operating the shaft. position while the inner shutter continues to pre- 16. A furnace having enclosing walls and at vent fluid flow through the chamber and for least one burner, means forming a chamber havmoving the inner shutter to open position while ing communication with the furnace through one the outer shutter prevents fluid flow through 5 of said walls and through which a torch may be v the chamber. passed to flre the burner, inner and outer shut- JOHN BLIZARD. ters controlling fluid flow through said chamber,

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