US3002505A - Tube heater - Google Patents

Description

Oct. 3, 1961 K. w. FLEISCHER TUBE HEATER 4 Sheets-Sheet 1 Filed July 28, 1958 I l6 l4 INVENTOR. KURT W. FLEISCHER g4 s hm ATTORNEY Oct. 3, 1961 K. w. FLEISCHER 3,002,505 I TUBE HEATER Filed July 28, 1958 FIG. 2 7 l6 l5 4 Sheets-Sheet 2 w f lmllm M UL f I i Ii 1 i |2-\ I l3 I l i 5 I i i ,J I $|4 1 w i T 5 l S I 5 INVENTOR. H KURT w. FLEISCHER BY S "1% ATTORNEY. I

Oct. 3, 1961 K. w. FLEISCHER 3,002,505

TUBE HEATER Filed July 28, 1958 4 Sheets-Sheet 3 INVENTOR. KURT W. FLEISCHER ATTORNEY.

Oct. 3, 1961 K. w. FLEISCHER 3,002,505

TUBE HEATER Filed July 28, 1958 4 Sheets-Sheet 4 F l G. 5

l I 32*- 1 I L INVENTOR. KURT w. FLEISCHER ATTORNEY.

3,002,505 TUBE HEATER Kurt William Fleischer, Philadelphia, Pa., assign'or to Selas Corporation of America, Dresher, Pa., a corporation of Pennsylvania Filed July 28, 1958, Ser. No. 751,315 7 Claims. (6]. 122-240) The present invention relates to heaters for processing fluids, and more particularly to heaters for heating a fluid as it is being forced through a tube.

In the petroleum and chemical industries there are many processes that require fluids to be heated continuously as they go from one portion of the process to another. Often a fluid must be raised in steps to different temperatures or raised to a given temperature and held there for a given time. These heating functions have been accomplished by the use of a plurality of heaters or by a complicated arrangement of tubes and bafiles in a single heater.

It is an object of the present invention to provide a fluid heater that is economical in construction and maintenance which can be used to heat a single fluid or a plurality of fluids to different temperatures. It is a further object of the invention to provide a fluid heater which has a plurality of heating compartments that may be completely or only partially separated.

In following the invention, there is provided a centrally disposed stack around which are located a plurality of heating compartments that extend radially from the stack. Each of these compartments is provided with one or more banks of tubes, with means for heating each compartment individually. The various tube banks may be separate or connected in various ways, depending upon the use to which the heater is to be placed.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:'

FIG. 1 is a plan view, partly in section, of one form of the heater;

FIG. 2 is a section through the heater taken on line line 2-2 of FIG. 1;

FIG. 3 is an enlarged view of the damper taken on line 3-3 of FIG. 1;

FIG. 4 is a plan view partly in section of another form of the heater; and

FIG. 5 is a section of the heater taken on line 5-5 of FIG. 4.

Referring to the embodiment disclosed in FIGS. 1 to 3, it Will be seen that the heater consists of a circular outer wall 1 and a circular inner wall 2, forming an annular heating chamber between the walls and a stack that is located centrally thereof. The chamber is completed by a floor 3 and a roof 4. As best shown in FIG. 2 of the drawings, the furnace is supported with the floor 3 raised above a supporting surface by means of a frame- Work which consists of structural steel members 5. The inner wall forming the stack extends to the supporting surface as shown at 6 and extends above the furnace as shown at 7, for a suitable height. The inner wall 2 is broken by a series of radially extending passages 8 which lead to the central stack. It will be seen best in FIG. 1 that the inner Wall 2 is provided with a series of openings 9 that extend from the top to the bottom thereof and through which project additional structural 3,002,505 iatented Oct. 3, 1961 steel members 11 to support the central portion of the furnace.

A plurality of banks of tubes are located radially in the furnace chamber between the inner and outer Walls. These tube banks may be either double rows of tubes as shown at 12 or single rows of tubes as shown at 13. In either event, the banks of tubes consist of vertically extending lengths of tube 14 which are joined by reverse bends 15 outside of the ceiling and floor respectively. The reverse bends are covered by separable housings 16 which are suitably insulated. By removing the housings the return bends become accessible for maintenance. The various banks of tubes may be connected to each other or they may be separate, depending upon the use to which the heater is placed and the process that the fluid flowing through the tubes is to be used with. The manner in which the various banks of tubes are connected, if such is the case, will depend upon the use of the equipment.

The tube banks, in effect, divide the heater into a series of sector shaped heating zones or compartments, each of which is heated by burners that can be adjusted separately from the burners in the other compartments. As shown herein burners 17 of a conventional type, fire upwardly through openings 18 in the floor that are provided for this purpose. The burners for each of the furnace compartments are supplied with fuel through a pipe 19 that has a regulating valve 21 in it. It will be apparent that a smaller or larger number of burners may be used depending upon the heating requirements of each compartment. It will also be apparent that the burners may fire downwardly from the roof, rather than upwardly from the floor as desired. Also burners may be put in the side walls of the furnace if desired. The criterion is that suflicientheat be supplied by suitable burners to each compartment of the furnace and that it be possible to regulate the burners of each compartment individually.

In order to control the draft in the furnace there is provided a damper 22 in each of the passages 8. As shown herein, this damper includes a vertically extending shaft 23 whose lower end is received in a bearing 24 and whose upper end is provided with an adjusting handle 25. The damper itself comprises a plurality of baffles or plates 26 that are fastened to the shaft 23 at spaced points along the same by means of straps 27. It may be necessary to provide intermediate bearings or guides for the shaft, one of which is shown at 28. In any furnace structure the tendency is for the products of combustion to rise to the top of the furnace and thereby create a higher temperature in the upper portion of the furnace than is obtained in the lower portion. In order to even out the flow of gases from the various compartments of the furnace to the stack the plates 26 of the damper are spaced different distances apart. As shown, the spacing between plates 26 is less at the upper portion of the passage than it is at the lower portion. For this reason more of the furnace gases will be discharged through the lower portion and thereby even out the heat to each compartment so that the top and the bottom of the compartments are heated to substantially the same temperature. 7

In the operation of a furnace of this type the fluid to be heated is directed through the various banks of tubes. If, for example, the fluid is to be raised in steps to an elevated temperature, the tubes on the opposite sides of one compartment would be heated by the burners in that compartment to a given temperature while the burners in an adjacent compartment would be fired harder so that the tubes on the sides of that compartment'would be heated higher. On the other hand, it may be that one of the compartments would be fired to raise the temperature of the fluid in the tubes to a given value and other compartments would be fired to maintain this temperature for a period of time. Since the various compartments can be fired to different temperatures, it is possible to have the banks of tubes connected to different sources of supply of fluid so that different fluids can be heated to the same or different temperatures. The banks of tubes, in effect, form a shield between each of the compartments so that they can be fired in such a manner that the temperature of one compartment will have little effect on the temperature of the other. It is realized that the tubes will not form a complete wall between each of the compartments and therefore, the temperature of one compartment will have some eifect on the temperatures of the adjacent compartments. The bafliing effect of the tubes, however, is suificient to make it possible to obtain wide variations in temperatures of the tube in the various compartments. It is noted that the openings 9 extend from thetop to the bottom of the furnace. This permits air to circulate through the inner wall of the furnace, which is the hottest portion, and thereby protect the steel framework and lengthen appreciably its life. It is also noted that dampers 22 can be adjusted to vary the draft in each of the compartments. It is possible to adjust plates 26 vertically along shaft 23 to vary the eflFect of the damper in each of the passages for any given position thereof.

Another form of the invention is shown in FIGS. 4 and 5. In this form there is provided a centrally disposed stack 31 that extends from a supporting base to a heighth that is necessary for the particular installation. A plurality of individual sectorshaped heating compartments 32, which are provided with a suitable floor and roof, are mounted in a vertical position around the stack. The compartments are mounted at a suitable elevation and supported in relation to the stack by means of structural steel members 33. The compartments, which are shown herein as being four in number, although any other suitable number could be used, are connected at their apexes to the stack 31 by means of passages 34 through which the products of combustion are exhausted to the stack. Each compartment is provided on each side thereof with a bank of tubes 35 that is formed of straight lengths of tube which are joined at their upper and lower ends by reverse bends 36. One end of the bank will be the supply end and the heated fluid will be discharged from the other end of the bank. The bends and the supply and discharge portions of the tube are received in insulated housings that can be attached suitably to the floor and to the roof, respectively, of the various heating compartments. Additional tube lengths can be placed in the apex of the compartments across exhaust passage 34 to form a convection section if desired. Each of these compartments is heated to bring the fluid flowing through the tube banks to the desired temperature by one or more burners 38. It is preferred that the burners used with a heating compartment of the type shown herein, should be of the bushy flame type. These burners are shown in FIG. as being spaced vertically along the outer wall of the compartment and extending through suitable openings 42 provided for this purpose. The burners are supplied from a fuel manifold 42a through valves 43. As is common in vertically elongated furnaces, there is a chimney eflect which carries the heated gases to the upper part of the chamber thereby giving a tendency for the upper portion of the chamber to be heated to a higherdegree than the lower. This is overcome in the present invention by spacing the burners closer together at the bottom than at the top of the heater compartment. In addition, there is provided a baffle 39 located in the passage 34 through which the products of combustion must travel to the stack.

' This baflle is shown as being provided with a plurality of openings 41 through which the products of combustion can travel with the openings being smaller near the top than they are near the bottom of the compartment. If desired, burners could be placed in the bottom of the compartments as shown, for example, in the embodiment of FIGS. 1 to 3, and as indicated in one compartment of FIG. 4. 'It is also noted that a damper of the type described above could be used instead of a fixed baffle if it is desired.

In this embodiment of the invention, as in the one previously described, the various tube banks can be connected in series or in parallel, or they can be separate as is desired for the particular operation or process in which the fluid to be heated is used.

It will be seen that this invention discloses a furnace having a compartmented construction that can be used for heating fluid flowing through a tube. This furnace is economical in construction, is designed to produce even heating of the fluid in each of the heating compartments, and requires a small area for a large number of tubes.

While in accordance with the provisions of the statutes, 1 have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. In a tube heater, the combination of a vertically extending stack, a plurality of vertically extending heating chambers shorter than said stack that are sector shaped in section surrounding said stack between the ends thereof, a burner in each chamber, means connecting said chambers to said stack at circumferentially spaced points around said stack with said chambers extending radially and with the apex of each chamber adjacent to the stack, said connecting means including means forming separate vertically elongated passages between said apexes and stack through which products of combustion can flow from a chamber to the stack, said passages extending for substantially the length of said chambers and equal distances above and below the vertical midpoint of said chambers, a damper in each passage, each damper being so formed that the lower portion of a passage is open more than the upper portion, and means to adjust said dampers.

2. In a tube heater, structure forming an annular chamber positioned vertically, a vertical stack taller than said chamber positioned centrally of said chamber and extending entirely through the same, means forming a plurality of elongated, vertically extending radial passages sub stantially the height of said chamber between said stack and said chamber, each passage extending equal distances above and below the vertical midpoint of said chamber, a radially extending row of vertical tubes in said chamber between each of said passages, means forming a floor under said chamber, and a burner in said floor between each row of tubes.

3. The combination of claim 2 including a plurality of spaced bafiies in each passage, the spacing between each bafiie diminishing as the elevation of the bafiles increases.

4. The combination of claim 2 including a damper in each passage, and means to adjust said dampers, said dampers being so formed that they open more at the bottom of a passage than at the top thereof.

5. The combination of claim 2 including means forming vertically extending passages in said structure, said passages being open at the top and bottom and being located between each of said rows of tubes and said stack.

6. In a tube heater, a vertically extending stack, said stack being provided with a plurality of narrow and vertically extending slots spaced around its periphery between its ends, a plurality of banks of tubes, said tubes being longer than said slots but shorter than said stack, means .to mount one of said banks of tubes in a vertical position extending substantially radially from said stack between each of said slots, each bank of tubes extending substantially equal distances above and below the ends of said slots, furnace structure around the outside of said tube banks and over the ends thereof whereby the spaces between said tube banks will form sector shaped chambers, a burner to heat each chamber with the products of combustion flowing through said slots, a burner between each bank of tubes and an adjustable damper in each of said slots.

7. In a tube heater, a vertically extending stack, a plurality of vertically extending tubes shorter than said stack forming a plurality of banks of tubes, means to mount said banks of tubes at substantially equally spaced distances around said stack between the ends thereof with each bank extending substantially radially thereof, furnace wall means surrounding said banks of tubes with the sector spaces between said tubes forming chambers, means forming a vertically elongated passage in said stack substantially the length of said tubes between the apex of each chamber and the interior of said stack, each passage extending equal distances above and below the vertical midpoint of said chambers, a burner to heat each chamber, the products of combustion flowing through said openings, and an adjustable damper in each openmg.

References Cited in the file of this patent UNITED STATES PATENTS 2,211,903 McCarthy Aug. 20, 1940 2,745,388 Becker May 15, 1956 2,789,521 Wasp Apr. 23, 1957 2,898,892 Campbell et a1. Aug. 11, 1959

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