Патент USA US2105819код для вставки
Jan. 18, 1938. R. M.>PARSON$ 2,105,819 FURNACE Original Filed June 16, 1934 W7 55 4 Sheets-Shéet l 36‘ 33 54 \ \\ \ \\ \\\\ \\ \\\\\\\\ \\\\\ \\\ 1.. _l__m INVENTOR ORNEY Jan. 18, 1938. 2,105,819 R. M. PARSONS FURNACE} Original Filed Jun e 16, 1934 4 Sheets-Sheet 2 36 // ~16 //////4l//// / / //// //// / /. 45 " BY ORNEY 2,105,819 Patented Jan. 18, 1938 UNITED STATES PATENT OFFICE 2,105,819 FURNACE Ralph M. Parsons, Mount Vernon, Ohio, assign or to The Ralph M. Parsons Company, Mount Vernon, Ohio, a corporation of Delaware Application June 16, 1934, Serial No. 730,874 Renewed May 25, 1937 8 Claims. (Cl. 196-110) This invention relates to furnaces and more ably the ?ame is caused to impinge directly on the lower rows of tubes. 7 particularly to pipe stills for treating hydrocar Other features of the invention consist in the bon oils. various details of construction and operation In heating hydrocarbon oils to high tempera 5 tures such as temperatures required for fractional distillation or for cracking, it is necessary to use precautions to prevent carbonization or coking of the oil, which tends to occur if the rate of heat transfer to the oil in the various parts of 10 the furnace exceeds certain values, varying with the temperature and nature of the oil. At the same time it is desirable to provide for the max imum permissible rate of heat transfer so as to conserve fuel, to utilize ef?ciently the available 16 heat, and to reduce the size of the furnace for a given output of oil. It is accordingly an object of the present in vention to provide a furnace having character istics suited for the above purpose. Another object is to provide a relatively cheap, simple, efficient and dependable furnace for the heat treatment of hydrocarbon oils. A further object is to improve the details of construction and method of operation of a fur hereinafter more fully set forth. Although the *5 novel features which are believed to be charac teristic of this invention will be more particularly pointed out in the claims appended hereto, the objects and advantages of the invention and the‘ manner in which it may be carried out may be 10 better understood by referring to the embodiment thereof disclosed in the accompanying drawings and more speci?cally described herein for pur poses of illustration. 15 In the drawings: Fig. 1 is a vertical longitudinal section through a furnace embodying the present invention and taken along the line l--l of Fig. 4; Fig. 2 is a vertical transverse section of the fur— nace taken along the line 2—-2 of Fig. 1 showing 26 the intermediate tube sheets and brackets; Fig. 3 is a vertical transverse section of the nace of the above type. furnace taken along the line 3—3 of Fig. 1 show ing the end tube sheets and brackets; Fig. 4 is a horizontal section of the furnace 25' Various other objects and advantages will be apparent as the nature of the invention is more taken on the line 4-4 of Fig.1; Fig. 5 is a partial end section taken on the line fully disclosed. 5—5 of Fig. 4; In accordance with the present invention the 30 furnace is constructed to provide for the direct flow of the furnace gases from the burners to the stack connection without substantial change in direction. In a preferred embodiment the ?ow is Fig. 6 is a partial perspective view of a tube sheet; 30. Fig. '7 is a broken perspective view of an inter mediate bracket; Fig. 8 is a broken perspective view of an end upward throughout the furnace, and the stack bracket; is located directly thereover. This construction reduces the resistance to the gas ?ow and permits attached to the intermediate tube sheet; the use of a relatively low and inexpensive stack. Another feature of the invention is the pro attaching the insulation to the end tube sheet; vision of side wall tubes closely adjacent the path 40 of the ?ame, in a position to receive heat both by radiation and convection so as to reduce the tem perature of the ?ame to a value such that the ?ame may impinge directly upon certain oil tubes without causing local overheating of the oil therein. The side wall tubes also largely shield the furnace walls from the intense radiant heat of the ?ame and prevent the walls from being damaged thereby. A bank of tubes, referred to herein as convec 50 tion tubes, is located in the upper part of the furnace chamber, directly in the path of the fur nace gases and is so disposed with respect to the burners that the lower rows of such tubes re ceive radiant heat from the ?ame as well as heat 55 by convection from the furnace gases. Prefer Fig. 9 is a sectional view showing the insulation 35 Fig. 10 is a sectional view showing the means of Fig. 11 is an end elevation of the furnace; Fig. 12 is a detail of the door hinge; Fig. 13 is a detail of the door lock; and 40 Figs. 14 and 15 illustrate diagrammatically dif ferent sequences of oil flow in the various tubes. In the various figures like parts have been designated by like reference characters. 45 Speci?c terms are used herein for convenience of description but it is to be understood that they are to be interpreted as broadly as the state of the :art will permit. Referring to the drawings, the furnace is shown 50 as comprising a pair of side walls I!) and a pair of end walls H forming a rectangular furnace chamber l2. The side and end walls may be formed of refractory or heat insulating material which may be arranged in two or more layers 55 2 2,105,819 or sections, preferably separated by an air space to provide for expansion and to reduce the heat loss. The furnace ?oor I3, consisting of con crete or refractory material, may rest upon an earth ?ll and may be provided with openings l4 located in the longitudinal median line there of to receive burners to be described. The walls may rest upon a foundation 15 such as concrete. 15 20 25 30 35 40 ’ 45 ' 50 of fuel therethrough and is thoroughly mixed with the fuel so as to obtain rapid and complete combustion. This construction accordingly elim inates many operating adjustments and auxiliary apparatus and improves the burner ef?ciency. Furthermore, the cold air passing under the ?oor l3 acts as a cooling means and prevents ex cessive heating of the, floor and foundation, thereby materially reducing the maintenance cost An external framework of structural members such as channels may provide the support for of the furnace. the various furnace elements. This framework The burner blocks may be entirely constructed may comprise vertical members l5, spaced along a of super-refractory but due to the high cost the side walls and anchored thereto as by angle thereof it is preferred to use only a lining of this irons l7. Said vertical members may be an material as indicated at (l2'at the points of great chored to the foundation l5 as by rods 20 em est heat. Such construction materially reduces bedded therein and secured to angle irons 2! the burner cost. which may be secured to the vertical members An inspection or clean~out door 50 may be lo l6 as by welding. cated in one wall of the furnace such ‘as a side The vertical members l6 may be joined at wall Ill. This door may be hinged to a frame their upper ends by transverse beams 22 and by 5| secured to the framework in any convenient longitudinal beams or angle irons 23. manner and seated in an opening 52 formed in The furnace also comprises a hood 30 which the furnace wall for this purpose. seats on the side and end walls and may be se The oil is heated in an upper bank 53 of con cured to the angle irons 23 which transfer the vection tubes and side wall tubes 10. The upper weight of the hood 30 to the frame-work. The tube bank 53 may comprise a plurality of verti hood may include a door 3| which may be hinged cally spaced rows of longitudinal tubes carried as at 32 to permit automatic opening in response in end tube sheets 54 and intermediate tube to explosions or puffs occurring in the furnace. sheets 55. The tubes of the different rows may The hood 363 communicates with a stack 33 which be staggered so as to obtain the fullest effect of may be provided with a damper 34 having an the heat of the combustion gases. The tube arm 35 adapted for remote operation by suit sheets 54 and 55' are each provided with upper able means (not shown). The stack 33 may be ears 55 which are engaged by stirrups 51 sup relatively short and may be supported directly ported by vertical rods 58, which in turn are hung by the hood 3!) and guyed if desired to the cor from the transverse beams 22. The various ners of the furnace as by guys 36. beams 22 are located above the hood 3!] and the A row of burners 40 may be located at the rods 58 extend therefrom through the hood to lower part of the furnace chamber l2 in a po the stirrups supporting the tube sheets. Obvi~ sition to direct the ?ame upwardly. Preferably ously, any number of tube sheets may be em said burners extend through the openings M in ployed although the four tube sheets disclosed the ?oor l3. The burners 40 may comprise blocks have been found satisfactory in a particular in of refractory material such as ?re clay or the stance. like having ?ared passages U shaped similar The end tube sheets .54 may be formed of suit to a Venturi tube so as to obtain an ei‘?oient able material such as cast iron and may be flow of gaseous. fuel and a thorough mixture of covered with moldable insulation 59 which may the fuel and air for combustion. The outer ends be held in position by wires 65 (Fig. 10). Said of the passages 4| may be lined with a super Wires 60 may be secured, as by welding, to pins refractory 42 such as high chrome non-metallic or nails 6|, which are cast directly in the tube refractory, preferably mixed with basic refrac sheet. The nails 6| may be bent over and the tory oxides adapted to withstand the high tem wires 65 may be twisted and/or welded thereto peratures of the ?ame. in the ?eld. The burners '40 may be su?iciently long to The intermediate tube sheets 55 may be made permit partial combustion to take place therein so that the ?ame may have reached a high tem perature opposite the lower side wall tubes, to 55 be described. Fuel supply pipes 43 extend to each burner 49 and terminate in jets 46 at the entrance to the passages 41. The pipes 43 may be connected to a main supply pipe 44 through valves 45 by 60 which the action of the various burners may be individually controlled. The air supply for the burners may be ob tained directly from the outside by air ducts M6 extending beneath the ?oor l3 and com 65. municating with the passages 4!. In this burner the ?ow of the fuel gases through the passages 4i induces a flow of air through the ducts I45, and the Venturi effect serves to effect mixing of the air and fuel. The area of the passages 70 4i and the position and area of the jets 45 may be such that the required air flow is induced without additional blower means. It is to be noted that all of the air for combustion is auto matically drawn through the passages 4| of the 75. burners by the suction induced by the passage 10 20 25 30 35 40 of cast iron or of a material such as steel which will permit wires (to be described) to be welded thereto. They may also be covered with insula tion 59 similar to that above mentioned which may be secured thereto by wires l?l. The wires I St may be looped and secured to the tube sheet at intervals, as by welds 62, to form a mesh or network about which the insu lation may be applied. Side ?anges 63 may be formed on the tube sheets 54 and 5.5 to confine the insulation 59 and to stiffen the structure. A lower ?ange 84 may be positioned above the two lower rows of tubes for the same purpose and the part below said ?ange 64 may be covered by insulation 65 which may extend around the bottom 66 of the tube sheets to protect the lower edge thereof. The insulation on the intermediate tube sheets 55 may terminate at a point short of the upper rows of tubes where the gases have cooled to a tem perature such that protection for the tube sheet is not required. The end tube sheets 54 are pref erably completely insulated on both sides so as 60 2,105,819 to reduce heat loss through the end doors (to be described). A set of side wall tubes it is located adjacent each side wall ill below the upper tube bank 53. The width of the furnace chamber l2 is such that the side wall tubes. are sui?ciently close to the ?ame to receive heat both by radiation and convection. Tubes 752 are carried in end tube brackets ‘H and intermediate tube brackets ‘i2. The end tube brackets ‘H are preferably made 10 of cast iron or steel channels covered with insu lation 8| similar to that above mentioned and may be hung from the end tube sheets 54 as by bolts 13. The intermediate tube brackets 72 may be 15 formed of alloy steel so that insulation is not required, thereby increasing the surface area of the tubes available for heat transfer. Since common bolts would tend to burn off if unpro 20 tected by the insulation and alloy bolts are ex pensive, the brackets ll2 may be attached to the tube sheets 55 by lugs ‘M formed on said brackets and having apertures '15 (Fig. 7) adapted to pass over and be supported by ears '16 extending from 25 opposite sides of the tube sheets .55. The ears '16 may be received in suitable recesses in the side walls it! which restrict transverse movement of the assembly. The end tube sheets may be an 3 Another sequence is indicated in Fig. 14 in which the oil enters the top row of tubes in the convection bank 53, passes down through the three upper rows, thence up through the three lower rows, thence down through the remaining 5 tubes of the convection bank, thence through the side wall tubes in the manner shown in Fig. 2. This sequence of ?ow may be advantageous where cooler oil is required in the lower tubes of the convection. bank which are subjected to the great est heat. The cooler oil in these tubes permits a higher rate of heat transfer without carboniza tion or local overheating of the oil. A further modi?cation is shown in Fig. 15 in which the cold oil ?ows downwardly through the 15 upper tubes of the convection bank, thence through the side wall tubes, and ?nally through the lower rows of tubes of the convection bank in a transverse direction. In this modi?cation the upper tubes of the convection bank constitute 20 a preheating section which extracts heat from the gases before they are discharged to the stack. The side Wall tubes which are heated both by radiation and convection constitute the main heating section in which the oil may, for exam 25 ple, be brought to cracking temperature, and the lower tubes of the convection bank, which are also heated both by radiation and convection, consti chored by stays TI to a suitable portion of the 30 furnace framework. tute a section in which heat may be transferred at a rate to maintain the oil at the required tem 30 The lower ends of the brackets ‘H and 12 may be held against the side walls H3 by stays Bil en gaging ears 8! on said brackets and extending through the side walls to the vertical members 35 it of the framework, to which they are secured. perature. Clearance is provided around the stays 85, par ticularly at the inner ends thereof, to permit movement in response to‘ expansion and con traction of the tube sheets andbrackets. 40 The end walls H are provided with a door 82 opposite the ends of the upper bank of tubes and with doors 83 opposite the side wall tubes, to afford access thereto. Said doors may also be lined with insulating material and may be hinged 45 to the framework by plates 88a. and. 81a (Fig. 12) which may be welded to the framework and to the doors respectively and receive hinge pins 88. Similar plates 89 and 90 are welded to the door and framework to receive a latch pin 9! (Fig. 13). 50 The plates may be attached by temporarily se curing the door in place, as by spot welding, then welding the plates in place and releasing the door by breaking the spot weld. This ensures an accurate ?t and requires only a minimum of time. 55 An inspection door 84 may also be provided in one end wall H which may be hinged as at 85 to a liner 86 within an inspection aperture 81 in the end wall II. The various tubes may be connected for oil 60 flow in any desired sequence. A preferred se quence for certain types of cracking is illustrated in Fig. 2 in which the oil inlet is indicated by pipe 92 which. leads to a tube in the top row of the upper bank 53. The various tubes are inter 65 connected by suitable return bends to provide oil fiow through the upper bank countercurrent to the combustion gases, thence through one set of side wall tubes countercurrent to- the flow of said gases, thence through the other set of side wall tubes concurrent with said gases, and out at pipe 93. The above sequence maintains an increasing rate of heat transfer up to the point at which the oil enters the side wall tubes, thence a some what reduced rate of heating throughout the rest 75 of the circuit It is obvious that various other modi?cations may be employed and that the furnace is readily adaptable for various uses by changing the con nections to the various tubes. It is to be noted that the position of the side tubes close to the ?ame causes the tubes to receive heat by convection as well as radiation whereby the heat is more quickly extracted from the ?ame. Such rapid extraction of heat serves 40 to reduce the temperature of the flame before it impinges on the lower tubes of the upper bank and to prevent carbonization or coking in such tubes due to local overheating. The side wall tubes partly shield the side walls 45 it from they direct heat of the flame and reduce the quantity of heat applied to the side walls so as to prevent heating of the walls to radiance. The upper tubes of the bank 53 are heated substantially entirely by convection whereas the 50 lower tubes of said bank and the side wall tubes besides convection heat also receive radiant heat. The construction accordingly provides a bank of convection tubes above the radiantly heated tubes and enclosedwithin the samev furnace chamber. 55 This feature is important as it avoids any sub stantial change in direction of the furnace gases after passing the radiantly heated tubes. In this way the resistance to gas flow is reduced to a minimum and the required ?ow of gases may be 60 obtained without using a high, expensive stack or a blower. The side wall tubes prevent appreciable heat loss by absorption of the side walls and roof. The end walls are of comparatively small area 65 and the heat loss produced thereby is not great. It is contemplated that the side walls may be’ made comparatively thin and of inexpensive ma terial since they are nearly completely shielded from the flame and are not required to absorb 70 a large amount of radiant heat and to transfer such heat by reradiation to the tubes. The mounting of all tubes directly from the out side framework simpli?es the construction prob lem since a minimum of weight is carried by the 2,105,819 tion may likewise be applied at the point of as side wall tubes onto the lower tubes of said con vection bank, and means to withdraw combus tion gases from the top of said combustion cham ber in substantially a direct line with said burn ers, whereby combustion gases pass through said .5 furnace upwardly without substantial change in direction, said side wall tubes being spaced to shield the side walls from the radiant heat of sembly. the flame and being disposed adjacent the path Although any standard method of joining the structural members may be employed, it is pre of the flame to receive heat both by radiation and 10 convection for rapidly extracting heat therefrom before the ?ame impinges on the lower tubes of furnace walls. By suspending the side wall tubes directly from the upper tuba sheets, relative movement between the tubes due to expansion is avoided and the necessity for expansion couplings is eliminated. The tube sheets and brackets are so formed as to be readily assembled in the ?eld. 10 ferred to use all welded construction. The insula This may be accomplished by use of simple welding devices which are readily available at the point of as 15 sembly. Although the invention has been illustrated as embodied in a speci?c device, it is to be under stood that various changes and substitutions may be made therein by a person skilled in the art. 20 The invention is accordingly to be limited only by the scope of the following claims when inter preted in View of the prior art. What is claimed is: 1. In a furnace of the class described, a tube 25 chamber, a bank of tubes in the upper part there of, tube sheets supporting said tubes, a structural framework, said tube sheets being supported by said framework and having ears formed at the lower part thereof, additional tubes below said 30 bank, brackets carrying said additional tubes, said brackets being hung on said ears and sup ported thereby whereby the entire set of tubes may expand and contract as a unit. 2. In a furnace of the class described, a side wall, a set of side wall tubes, tube supports car rying said tubes, means suspending said supports, and a link extending through said side wall to hold the lower part of said supports thereagainst, said side walls having su?icient clearance around said link to permit vertical movement of said supports due to expansion thereof. 3. In combination, a furnace wall, a tube sheet the convection bank. 6. An upshot oil still comprising, in combina tion, a rectangular combustion chamber, a con vection chamber above said combustion chamber and formed as a continuation thereof, a bank of horizontal, longitudinally extending convection tubes carrying hydrocarbon oil substantially ?ll ing said convection chamber, transverse tube 20 sheets carrying said convection tubes, a row of horizontal radiant heat tubes extending verti cally below said convection tubes, brackets sus pended from said tube sheets carrying said radi ant heat tubes, a row of burners at the bottom of said combustion chamber and spaced longi tudinally thereof to direct the ?ame past said radiant heat tubes toward the lower tubes of said convection bank, and means to withdraw com bustion gases from the top of said combustion ’ chamber in substantially a direct line with said burners whereby the combustion gases pass through said furnace upwardly without substan tial change in direction, said radiant heat tubes being disposed adjacent the path of the ?ame to receive heat both by radiation and convection for rapidly extracting heat therefrom before the ?ame impinges upon the lower tubes of the con vection bank. '7. An upshot oil cracking still comprising, in combination, a rectangular, elongated combus rigidly supported with respect thereto, said tube tion chamber, a convection chamber above said combustion chamber and formed as a continua sheet having a transverse lug entering a recess tion thereof, a bank of horizontal, longitudinally 45 in said wall, a tube carrying bracket adapted to hang over and be supported by said lug, and means securing the lower end of said bracket against said wall while permitting vertical move ment of said bracket in response to expansion 50 and contraction thereof. 4. In combination, a furnace wall, a tube sheet extending convection tubes carrying hydrocar bon oil substantially ?lling said convection chamber, transverse tube sheets carrying said convection tubes, a row of horizontal side wall radiant heat tubes on both longitudinal side walls below said convection tubes, a plurality of verti cal brackets supported only at one end, each rigidly supported with respect thereto, said tube bracket extending in supporting engagement with sheet having a transverse lug entering a recess in said wall, a tube carrying bracket adapted to 55 hang over and be supported by said lug, and means securing the lower end of said bracket against said wall while permitting vertical move ment of said bracket in response to expansion and contraction thereof, said means comprising rods 60 extending through enlarged openings in said wall and anchored externally thereof. 5. An upshot oil still comprising, in combina tion, a rectangular combustion chamber, a con vection chamber above said combustion chamber 65 and formed as a continuation thereof, a bank of horizontal, longitudinally extending convection tubes carrying hydrocarbon oil substantially ?ll ing said convection chamber, transverse tube sheets carrying said convection tubes, a row of 70 horizontal side wall tubes on both side walls be low said convection‘ tubes, brackets suspended from said tube sheets carrying said side wall an entire row of said radiant heat tubes, a row of burners at the bottom of said combustion chamber spaced along the center line thereof to ' direct a ?ame upwardly between said rows of side wall tubes onto the lower tubes of said con vection bank, and means to- withdraw combus tion gases from the top of said combustion cham ber in substantially a direct line with said burn ers, whereby combustion gases pass through said furnace upwardly without substantial change in direction, said side wall tubes being spaced to shield the side walls from the radiant heat of the ?ame and being disposed adjacent the path of the ?ame to receive heat both by radiation and convection for rapidly extracting heat therefrom before the ?ame impinges on the lower tubes of the convection bank. 8. An upshot oil cracking still comprising, in combination, a rectangular, elongated combus tubes, a row of burners at the bottom of said com tion chamber, a convection chamber above said bustion chamber spaced along the center line combustion chamber and formed as a continu 75 thereof to direct a ?ame between said rows of ation thereof, a bank of horizontal, longitudinal 75. 2,105,819 1y extending convection tubes carrying hydro in carbon, oil substantially ?lling said convection chamber, transverse tube sheets carrying said convection tubes, a row of horizontal, longitudi nally extending radiant heat tubes, said row ex tending vertically below said convection tubes, a plurality of vertical brackets supported only at one end, each bracket extending in supporting engagement with the entire row of said radiant 10 heat tubes, a row of burners at the bottom of said combustion chamber and spaced longitudinally thereof to direct the ?ame upwardly past said radiant heat tubes onto the lower tubes of said 5 convection bank, and means to withdraw com bustion gases from the top of said combustion chamber in substantially a direct line with said burners whereby the combustion gases pass through said furnace upwardly Without substan tial change in direction, said radiant heat tubes being disposed adjacent the path of the flame to receive heat both by radiation and convection for rapidly extracting heat therefrom before the ?ame impinges upon the lower tubes of the con- 10 vection bank. RALPH M. PARSONS.