US2374178A - Means for regulating the passage of gases in heat exchangers - Google Patents

Description

April 24, 1945. D. DAMN 2,374,178

'MEANS FOR REGLATINGI THE PASSAGE OF GASES IN HEAT EXGHANGERS 2l y n /5 24 April 24, 1945.- D. DALIN 2,374,178 MEANS FOR REGULTING THE PAS-SAGE OF GASES IN HEAT EXCHANGERS `Fled Dec. l2, 1942 2 Sheets-Sheet 2 Parc-nica Apr. 24, A19.45

MEANS FOR REGULATING THE PASSAGE F GASES IN HEAT EXCHAN GERS Davia Daun, sccicrtclje, sweden Application Dcccmbcr 12, 1942,'scria1 Nc. 468,832 In Sweden September 16, 1941 v 7 Claims.

invention relates to heat exchange apparatus and-.refersparticularly to a shutter or damper construction for controlling the flow` of temperature modifying gases through a gas pass in which a heat exchanger may be located.

There are many instances .in heat exchange apparatus where it is desirable to regulate the flow of hot gases-through a gas pass and thereby control the effect of the hot'l vgases upon a heat exchanger which may be a superheater or the like. One such instance is found in steam generators wherein the furnace has an oiltake gas passage in which a superheater is located. Thus, by controlling the amount of the hot gases which pass through that portion ofthe oitake gas pasisage in which the superheater is located a predetermined output condition may be maintained for the steam generator.

With this general objective in view, it is an object of the present invention to provide a shutter or damper construction for controlling the passage of gases through an opening and wherein the shutter or damper comprises a bank of fluid cooled tubes certain of which are movable with respect to others to vary the spacingl between the f' tubes and thereby regulate the flow of gases through the opening. f y

More specifically, it is an object of this invert l .tion to provide a heat exchange` I apparatus quibpdwith cooperating walls whichfderi pri` c marf'yzandsecondary gas passagesconnectedfby a.

inlet and a by-pass opening. and wherein a bank of liuid--cooled tubes extending-across the by-pass opening serves to regulatev the liow` of hot gases-through that portionyof the secondary ypassage lying between themain inlet and the .iacent'tubes and thereby determine the effectivenation and arrangement, of parts substantial]y as hereinafter described and more particularly.v defined by the appended claims, it being under' stood that suchV changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the inventionconstructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a vertical-sectional view through a steam generator illustratingI one application of Figure 5 is a-vicw simuar'tc Figure a, but shcwflexed to vary their positions with respect to adness of the barrier formed by the b'anli of tubes.

The present invention is particularly advantageous in the control of gas flow through separate'passageways of thev furnace chamber in a steam generator for the reason that one set of tubes may be used` to form the variable shutter or damper and also line the furnace walls to simultaneously insulate the furnace walls and constitute part of the boiler heatjexchange surface.

Withthe above and other objects in view, which will appear as the description proceeds, this invention resides in the novel construction, combithe invention;

Figure 2 is an enlarged view showing a portion .taken Ithrough Figure 2 on the plane of the line 3-3 and showing the open and closed positions of the damper; and' ing a slightly modified arrangement of the tubes.

`Referring now particularly to the accompanyink drawings in which like numerals indicate like parts, the numeral 5' designates a partition wall which cooperates with fixed furnace walls 6, 1, and' to form a primary gas passageway 9 and a secondary gas passageway I0, the furnace walls' having a refractory lining I I.

, me tcp cf the partition wan s is spaced frc'ncy the top furnace wall 1 to provide a main'inlet opening I2 'connecting the primary and secondary gas passageways at the top. A by-pass opening I3 in the partition wall and spaced downwardly from the top thereof provides another point of communication between. the two passageways.

The area of the secondary passageway III lying y between the main inlet opening f I2 and the bypass opening I3 constitutes a heating chamber Il in which a superheater I5 is located.

The inlet 'ends .of the superheater coils are connected with an inlet header I6 which in turn is connected to a steam drum I1 by a. supply line.'

partition wall `5. The tubes or coils then con I tinue across the secondary gas passageway tol a point adjacent to the top of the partition wall where they are directed abruptly upwardly and downwardly to form hairpin bends 22 and continue downwardly across 4the face of the partition wall defining one side of the primary gas pas- I SageWaY,

Adjacent tubes or coils have their hairpin portions 22 oilset so as to permit the flow of combustion gases through the main inlet opening I2, the extent of the odsetl determining the freedom of gas flow through the main inlet.

At the by-pass opening I3 the tubes or coils are disposed inside by side relation to normally close the by-pass opening so that the gases enter the secondary gas passageway into openings 24 in` the wall 8 where they are looped back on themselves as at 25. The loops 25 havelinks 26 connected thereto and extended out through the wall 8 to provide means for applying endwise motion to the looped portions of the coils.

The mechanism by which-such motion may be imparted to the coils comprises a shaft 21 mounted for oscillation and providedwith levers 28 which have their free ends connected to the links 26. A gear-segment 29 secured to the shaft 21 meshes with a pinion 29' driven from a Selsyn type motor 3l by a worm and worm wheel 3|. A coveror housing 32 preferably encloses the projecting ends of the links and their actuating levers to close the openings 24.

The Selsyn type/motor is controlled by an impulse organ or regulating mechanism Il responsive to temperature sensitive control means (not shown) but governed by the temperature of the steam issuing from the superheater, the im pulse organ acting through a relay 2l.

Upon oscillation of the shaft 21 either by the Selsyn type motor or by a manually actuatable handle 35 allof the levers Il and all of the coils driven thereby are pushed or pulled to flex the tubes so connected thereto and extending across the by-pass opening to vary their spacing with relation to the other stationary tubes which continue straight across the by-pass opening. Thus, it is possible to adjust the size of the bypass opening to permit the hot combustion gases to by-pass the superheater coils andV thereby maintain a predetermined temperature condition for the steam issuing from the superheater.

It is, of course, obvious that the levers It can be mounted on the shaft 21 in different positions of angular relationship so that certain of the coils will lbe moved farther than others if this is found desirable or necessary to maintain proper control for the flow oi' hot gases or for like purposes the links may have a lost motion connection with their respective levers 2l.

The tubes or coils 2l are adapted t6 have a suitable coolant, as for instance. a water-steam emulsion, continuously circulateds therethrough and as will be readily apparent, the tubes, or coils may'constitute part of the heat exchange surface .of the boiler. Therefore, they not only serve the dual function of increasing the heating surface of the boiler and of providing a controllable damperor shutter for the by-pass' opening I3, but, lining the wallsofthe furnace chamber as these walls from direct said partition wall having a main opening through which said passageways are connected for the flow of hot gases from the primary passageway into the secondary passageway and having a bypass opening spaced from the main opening through which thehot combustion gases may flow to avoid the area inthe secondary passageway lying between said openings; a heat exchange device in said area of the secondary passageway; a bank of fluid cooled tubes extending across said bypass opening to form a barrier of variable eiectiveness depending upon the spacing' of said tubes, said tubes extending along the partition wall to a point spaced a considerable distance from the bypass opening, certain of the tubes having their portions which extend across the bypass opening movable with respect to the other tubes by flexure of their portions remote from the bypass opening; and means connected to said movable tubes for flexing said tubes to vary the effectiveness of the barrier across the bypass opening. and consequently the ailect of the hot combustion gases on the heat exchange device. Y

2.- In a heat exchange apparatus: fixed iurnace walls; a partition wall cooperating with said ixed furnace walls to define adjacent primary and secondary passageways for hot combustion gases, vsaid partition wall having a main opening through which said passageway/s are connected i'or` the iiow of hot gases from the primary passageway into the secondary passageway and having a bypass opening spaced from the main opening through which the hot combustion gases may flow to avoid the area in the secondary passageway lying between said openings; a heat exchange device in said area of the secondary passageway; a bank of fluid cooled tubes extending across said bypass opening to form a barrier of variable effectiveness depending upon the spacing of said tubes, the tubes of said bank extending across the partition wall between its two openings and across the main opening where they have a reverse bend, the spacing of the tube portions extending across the main opening-being substantial so as not to interfere too greatly with the flow of gases from the primary passageway into the secondary passageway, the portions of 'the tubes extending across the bypass opening being normally closely adjacentto each other to -form an effective barrier; and means connected `to certain of the tubes at the bypass opening'for flexing said tubes from their reverse bends to alter the spacing between the tube portions extending across the bypass opening and thus vary the effectiveness of the barrier across the bypass opening and correspondingly alter the affect of the hot combustion gases on the heat exchanger.

3. Inga heat exchange apparatus: fixed furnace walls; a partition wall cooperating with said fixed furnace walls to deilne adjacent primary aaraifia opening to line part o the walls of the secondary passageway, said tubes also extending across the partition wall space intervening its openings, and

certain of the tubes having continuations thereof passing through the bypass opening and extending across the secondary passageway to a point adjacent to one of the fixed furnace walls; and means on the exterior of said xed furnace wall and connected to said adjacent tube portions for moving said portions toward and from the partition wall so as to ex the tubes'connected thereto and thus shift the-same relative to the other tubes extending across the bypass opening to vary the effectiveness of the barrier across said bypass opening.

4. In a heat exchange apparatus of the character described; cooperating iixed walls denning a passageway for hot combustion gases, said passageway having an inlet through which hot combustion gases normally enter the same, one of the walls defining said passageway having a, bypass opening through which the hot gases may flow into the passageway and thus bypass that 4 part ci the passageway lying between the bypass opening and the inlet; a bank of uid cooled tubes overlying said wall and extending across the by-pass opening, said tubes in their normal positions being closely adjacent to substantially close the bypass opening, certain of the tubes being bent abruptly and extending through the bypass opening across the passageway to the opposite wall thereof at which point said tubes have a return bend to again cross the passageway and extend through said bypass opening; and means exteriorly of said passageway and connected to the reversely bent portions of the tubes for shifting the same toward and from the wall in which4 the bypass opening is located to thereby hex the tubes connected thereto out of their normal positions `to vary the spacing between vthe tubes forming the barrier across the bypass opening.

5. In a heat exchange apparatus of the character described: fixed furnace walls; kan upright, partition wall cooperating with the' furnace walls to dene substantially vertical primary and secondary passageways for-hot Acombustion gases, the top of said partition wall being spaced from the top fixed furnace wall to provide normal communication between said passageways, said partition wall having a bypass opening spaced downwardly oi' its top, the space in the secondary passageway between the top of the partition wall and its bypass opening serving as asuperheater chamber; a superheater in said chamber; a bank oi fluid cooled tubes covering the upper portion of the partition wall and extending across the bypass opening to form a barrier of variable eiectiveness depending upon the spacing of the tubes, certain of said tubes being movable at least in their portions which extend across the bypass opening to varythe eiectiveness of said barrier, said movable tubes having lop portions extending through the bypass opening and across vthe secondary passageway to a 'point adjacent to 'tubes andlthereby vary the effectiveness oi the barrier and correspondingly alter the affect of the hot combustion gases on the superheater.

6. In a heat exchange apparatus of the character described: ixed furnace walls; an upright partition wall cooperating with thev furnace walls to define substantially Vertical-primary and secondary passageways for hot combustion gases, the top of said partition wall being spaced from the top fixed furnace wall to provide normal cornrnunication between said passageways, said partition wall having a bypass opening spaced downwardly of its top, the space in the secondary passageway between the top of the partition wall and its bypass opening serving as a superheater chamber; a superheater in said chamber; a bank of fluid cooled tubes covering the upper portion of the partition wall and extending across the bypass opening to form e, barrier of variable eii'ectiveness depending upon the spacing of the tubes, certain of said tubes being movable at least in their portions which extend Aacross the bypass opening to vary the effectiveness of said barrier, said movable tubes having loop portions extending through the bypass opening and across the secondary passageway to apoint adjacent to the opposite fixed furnace wall; and means exteriorly of said fixed furnace wall and connected with said looped portions for shifting said looped portions toward and from the partition wail to shift -the partition wall being spaced to permit4 the iiow of hot combustion gases therebetween.

7. In a heat exchange apparatus: fixed furnace walls; an upright partition wall cooperating with the furnace walls to define adjacent primary and secondary passageways; af main opening connecting -the primary and secondary passageways; said partitiouwall having a bypass opening at a distancerom said main opening through which hot combustion gases flowing in the primary passageway towards themain opening may enter the secondary passageway before they reach the main opening and thus bypass the space in the secondary passageway beyond the bypass opening; a superheater in said space; a bank of liquid cooled tubes connected'to'a source of cooling liquid and extending across the bypass opening and by their spacing controlling the amount vof hot gases which bypass-the superheater in the secondary passageway beyond the bypass opening; and'means connected to certain of said tubes in the region of the bypass opening for exing said tubes to shiftitheir portions which extend across the bypass opening with respect to the remaining tubes and thus vary the spacing between the tubes to control the amount of the hot gases which bypass the superheater.

DAVID DALIN.

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