March 20, 192-8. ' 1,662,991 ' P. THOMSEN AIR PREHEATER Filed Jan.16, 1925

lpai’ér Z?Q'mJen/INVENTOR

£14 A TTORNEV

Patented Mar. 20, 1928. * weasel hair-a; stares nestles. VIPETER'THOMSEN, 0-15‘v CASSEL, GERMANY, ASSIGNOR TO THE COMPANY, OF'NEW YORK, N. Y.,' A CORPORATION OF DELAWARE.

AIR PREHEATER. ‘Application ?led January‘ 16,1925,‘ Serial No. 2,774, and in Germany March '3, 1924.. The subject ‘of the present invention is a FigureQ shows a water tube ‘which 55 ‘boiler for'movable steam power'installation, comprises lateral and upper steam and'wa ‘?nding ' application particularly ~ in connec ter‘drums and cross tubesconnécting‘them, tion with locomotives. and is equipped with a superheater which 5 . According to the invention an air ‘pre can be removed‘through the smok-ebox; v:Fig heateris built intoa boiler in'su'ch a manner ure 3 shows a boiler equipped with therusual 60 ‘that the longitudinal axis of the lpreheater smoke tube superheater; Fig. 3a showsion extends substantially in‘ an ‘up'and down di~ a larger scale a detail of Fig. ‘3; Figures .rection, and the air is supplied to ‘the "air 4: and 5 show other forms of the; invention. 10.preheater through an opening in‘ the up In Figure '1 the boiler 2, which is equipped per part'of the v‘front ‘wall of the'smoke‘ with smoke tubes 3, is so shortened that the 65 box. The preheater preferably comprises 4 is longer than usual. In'the ' parallel pipes. Contrary to known-arrange smokebox an air preheater 5, consisting of ments of ‘air 'preheaters which lie entirely parallel tubes, is ‘arranged so 1'that its gen 15 ‘or for their greatest party in ‘the lower part eral direction is diagonallydownwardzfrom 'of‘the smoke chamber'and have 'an'air sup front to rear. In the upper "portion'of'the ply opening which is arranged 'at'the'lower ‘front wall of the smokebox there is pro part of the front wall of'the smoke chamber, vided an opening‘ 6 from whichY-aichannel 7 the present arrangement presents the ad leads'to the 'air‘preheater 5. The channel 20 vantage that during the motion'of the boiler 7 surrounds the stack '8. The dimensions the air can enter better‘ and with less dis of‘ the channel ‘7 "are so chosen thattheiopené ‘ turbance than if the ‘supply opening for the ing ‘(Sat the'front wall/of the smokebox is ‘air is atthe lower part of‘the' front wall .materially' larger than the opening of the of the smokebox, as in the latter position channel leading to the‘preheater 5 ‘so‘that 25 of the air op'ening‘the air‘is diverted up a sort of funnel is‘ formed. 'Therain?ows wardly. ' in ‘through-‘the channel 7, as indicated-by _ In connection ‘with the use of'an air pre the arrowf?ows ‘next through thepreheater heater according to the present invention, 5, and then ‘through the channel ‘9, which aiboiler of any preferred formfmay be used. lies below ' the‘ boiler and ‘carries the an: ‘to 30 For example, the boiler can 'beshortened a'point below ‘the grate. - to such an extent that'there is still sufficient The shortening o'f-theboiler 2 and<0f the 85 best left at the exit vof the hot'gas'es from ‘boiler tubes 3 is so calculated that-thexhot the fines, and before these hot gases are gases leave the tub‘es'at a temperature‘ still allowed to come into contact with the pre high enough" thateven after the requisite- heat 35 heater ‘so that the steam can be ‘raised to is abstracted for superheating thesteamin the desired degree of superheat in av super a superheater v1O located between'the smoke 90 heaterv which is removable either upwardly box ‘end of the boiler and'the preheater -5 or laterally. However, a fsuperheater vmay ‘there is'su?icient'heat 1left "to preheatv the also be chosen which can be removed through air flowing through the preheatermto-‘the 40 the smokebox after the “manner of a smoke desired temperature. The superheater :10, tube superheater, or which can‘ be ‘con to which saturated steam from'the‘boiler is 95 structed according to the usual form of delivered by pipe 11, is in-the'illustrative smoke tube superheater. In this "case ‘the exampleso arranged that it canlbe taken air preheater must be ‘so arranged that it out upwardly from the‘smok'ebox through an opening 12, which is normally'olosed- but 45 can be removed out of "the direct path of can be opened for ‘ this > purpose. ' The-super 100 the superheater elements. 7 ' ' ' In the drawings there‘are represented dif heater can also be soarra'nged that'itqcan ferent illustrative'forms of accord be removed laterally from the ‘smokeb‘ox. ing, to this invention.~ Figurel shows ~the The best arrangement vforuthe lsuperheater ‘is such that the steam which is»to“be;-super 50 ‘smokebox of a '?retube "boiler withv an air p'reheater and witha s'uper'heat'er 'whichlat heated ?ows throughiit'iin‘a directiomcoun 105 ' iter can be removed in an upward vdirection, ter to that in which the hot gases arewmove this saperheate'r lying between the’ front tube ing. In the illustrative example thesatu - the ‘boiler ‘and the fair’ preheat'er; rated steam.v is thereforemad'eto enter the 2 1,662,991

superheater pipes at 13 and the superheated opening 6 in the upper part of the front steam leaves the superheater at 14 where it wall through which air ?ows into the chan enters the superheater header 15. nel 7 to flow thence through the tubes of the By means of the above mentioned funicu air preheater 5, after which itis carriedto lar form of the channel 7 the resistance a point below the grate through the duct- 9. which the air will-encounter in the pipes The tubes 5 lie in a diagonal direction from of the preheater and in the channel9 is the front rearward and downward. The air more easily overcome, while the resistance preheater 5 is in this case so arranged that at- the grate and the friction in the ?nes‘ and it can be rotated about the axis 27 into'the in the smoke chamber are taken care of in approximately horizontal position indicated 75 the usual way by means of the exhaust noz by the dotted lines. In the normal position ‘zle 16. - indicated by full lines it is held by means WVhile in the arrangement according to of a latch or the like 28 and 29,vor in any Figure 1 the air preheater ispermanently other desired manner. This is shown on an built ‘in and. the superheater may be re enlarged scale and more clearly in Fig. 3‘‘. 80 moved either upwardly or laterally, provi When the air heater is in its normal position, > sion must be made in those types of super the latch 28 engages the angle iron E which - heaters which are removable through the "is secured to the upper end of the heater by - - smokeboX so that the air preheater may means of the piece H and the angle, J, and 20 readily be removed out of the path of the thus keepsthe heater in position. l/V hen it 85 isuperheater elements. This is done in the is desired to lower the heater into the posi» forms givenby way of illustration in Fig tion indicated in dotted lines in Fig. 3. the ’ ures 2 and 3. . ‘ latch 28 is moved out of engagement with E, In Figure 2 the. smolirebox 4 is again and the heater is lowered by means of the 25 equipped at its upper portion with an open cable G, which 1s secured toone or more of‘ ing 6. through which the channel 7 ‘ leads to the tubes and is wound on the drum C. ~ the upper end'of the air preheater 5. The The crank D'for rotating drum lies out latter/is so arranged that its tubes lie in a side of the smokebox. . In this case also the I vertical position and that it may be integral air preheater 5 is removed out of the path 30 removed upwardly from the smokebox of the superheater elements when it is de " through’ the normally'closed opening 17. sired to remove or reinsert them. It need ‘ The cover B is made removable for this pur not however be removed entirely from the pose.‘ The de?ecting plate A is preferably smokebox, but may be simply rotated down I secured directly to cover B so‘ the two are into the dotted position. a removed'together. The air which enters at By means of the ‘arrangement described" 100 ‘ the opening 6 in this case also ?ows around and illustrated of a boiler with a preheater the stack 8 while passing through the chan lying in the smokebox, there can in all cases nel 7, and after it’ has passed through the be obtained a sufficient preheating of. the ' preheater 5 vreaches the duct 9 and thence air and su?icient heat will be re the grate. In the duct 9 there is arranged moved from the waste gases. Generally it 105 ' in Figure 2 a sort of hopper 18, through will. be su?icient if the temperature of the _ which cinders carried along by the hot gases vcombustion air is raised to about 1000 C. can be removed. This hopper 18 is sur Assuming by way of illustration that the rounded by the air ?owing through the desired superheated. steam temperature is to be 350° C; then the gases leaving the super~ 110 In this case the boiler consists of an upper heater will-have an approximate tempera ‘steam chamber 19 and-of lateral steam and ture of 850° C. and can give'up approxi 'water chambers 20, which together form an mately 100° C. to the air ?owing through - upper and two lateral walls. The chambers the air preheater so that they will reach the‘ 50 are connected by cross pipes 21. In the in stack with a temperature of about 250° C. ' termediate spaces left free by these cross In practicing the invention according to Fig pipes there are located the serpentine ele ure 1 in which the smoke tubes are shortened, ments 22 of a superheater whose saturated thearrangement will be such that the gases and superheated headers are respectively will leave the ?ues with a temperature of ap 55 numbered 23 and 24. If it is desired to re~ proximately 500° to 550° C. and‘ come into‘ 120 move any of the elements 22 through the contact with thesuperheater at such a tem~v smokebox or to insert them, the air pre perature. Here they give upto the steam heater v5 must ?rst be removed upwardly which is to be superheated approximately through the opening 17 . 200° C. so that they-will leavethe super 60 In Figure 3 there is represented a ?re tube heater for the air preheater at about 350? 25 boiler 2 with ?re tubes 3, which is equipped C., give up to. the air passingthrough it with a smoke tube superheater of the usual about 100° C. and pass on to the stack at type in which the serpentine elements 25 lie about 250° C. In all ofthe cases which have_ ' in the smoke tubes and open into a common‘ been described and shown and in all similar 65 header‘ 26. The smokebox 4 again has the cases which fall within the scope of this in 1,662,991 I ' 8

vention there is therefore obtained a par-' the front, The lower ends of the pipe 5 are ticularly economical utilization of the heat so arranged that, viewed in the direction of ‘ of the gases, together with the desired the boiler axis, they lie behind each other. 60 amount of superheating and of the preheat The openings in the lower tube sheet in C21 ing of the combustion air. which the bent ends of the-pipe 5 are se If desired the shortening of the boiler can cured lie in parallel vertical rows. In the be carried even further so thatin addition upper tube sheet the openings are staggered to superheating the live steam and preheat so that there results a sloping position of 65 ing the combustion air the hot gases leave some of the pipes 5 as indicated in Figure 5. 10 the boiler at an even higher temperature In this way there is provided in the lower and can be used to reheat the steam in an in part of the preheater a comparatively free termediate reheater as it flows from one passage for cinders, while in its upper por stage of the engine to the next. In Figure tion the is improved by means 70 4: an illustrative case of a boiler of this type of the particularly good contact of the heat 15 is shown in which this is made possible. As ing gases withthe greatest possible amount in the form according to Figure 2, the boiler of heating surface. here also consists of uppenchambers 19, The air preheater which is represented in lower chambers 20 and cross tubes 21 con Figure 4 could be made out of plates in a 75 necting them. The superheater which super previously known manner which would take heats the live steam is arranged in the the place of the pipes. smokebox beyond the boiler and can, as in ‘What I claim is: , ' ' the case of Figure 1, be removed through 1. In a locomotive boiler, the combination the normally closed opening 12. The super of a. smokebox into which gases are dis 80 heater here also as in Figure 1 comprises charged from the boiler Hues, a stack ex 2.5 the ‘distributing header 13 (which receives tending through the forward upper part of ' steam from the boiler through pipe 11) and the smokebox sheet, an intake for air at the superheater elements 10 from which the the upper part of the front wall of the ‘steam ?ows at 14: to be delivered into the smokebox, a. passage extending rearwardly 85 superheated chamber 15 whence it is carried from the intake and surrounding the stack, to the high pressure stage of the engine. In an air preheater comprising two parallel addition to this live steam superheater an tube sheets and tubes connecting them, a intermediate reheater consisting of serpen duct extending rearwardly from the lower ' tine tubes 30 is arranged in the smokebox part of the smokebox, the air preheater ex 90 beyond it. This reheater can also be re tending from the rear end of said passage 35 moved through the opening 12. The steam to the front end of said duct, superheater which is to be reheated enters the chamber elements extending into said ?ues, said pre 31 and flows also in a direction counter to heater being hinged at its lower‘ end so it the heating gases through the elements 30 can be rotated out of the direct line‘ ofsaid to the chamber 32 whence it ?ows to the next elements, and means. to hold the preheater 40 stage of the engine. in its normal operative position. ' In Figure'll there is also shown a variation 2. In a locomotive boiler equipped with of the form of the air preheater. Its tubes tubular superheaterelements extending into 5 extend vertically downward from the hori the boiler from the smokebox, the combina 100 zontal inner end of the channel 7 and then tion of said smoke-box; anintake for air 45 turn at right angles into the vertical parti at the upper part of the front wall of the tion at the front end of duct 9. Since the smoke-box; an air preheater comprisingtwo two can be removed upwardly tube sheets and tubes . connecting them; it is not necessary in this case to make pro a duct extending rearwardly from the lower 105 vision for ready removal of the air preheat part of the smoke-box; the air preheater 50 er. This form of the air preheater with the being arranged in front of said superheater curved pipe ends has the advantage that no elements and receiving vair from the intake cinders can lodge on the tube sheet to which and discharging it into the duct; and the the pipes are secured at the end opening into air preheater being readily removable as a 110 the air duct. , p unit out of ‘the direct line of said superheater In Figure 5 there is shown a special form elements. 7 - of an air preheater of the kind indicated in Figure 4:, the heater being viewed from PETER THOMSEN.