US2204155A - Fluid heat exchange device - Google Patents

Description

June 11, 1940. c@ u. SAVOYE FLUID HEAT EXCHANGE nnvrcn Filed Nov. 15, 1934 5 Sheets-Sheet 1 INVENTOR Charles U Sav aye June 11, 1940.

C. U. SAVOYE FLUID HEAT EXCHANGE DEVICE Filed Nov. 15, 1934 5 Sheets-Sheet 2 June 11, 1940. C u SAVQYE 2,204,155

FLUID HEAT EXCHANGE DEVICE Filed NOV. 15, 1934 5 Sheets-Sheet 3 5! INVENTOR Charles (I Savage June 11, 1940. c. u. SAVOYE FLUID HEAT EXCHANGE DEVICE Filed Nov. 15, 1934 5 Sheets-Sheet 4 INVENTOR Char/es U. Sax aye QS%I\IEY June 11, 1940. c. u. SAVOYE FLUID HEAT EXCHANGE DEV ICE Filed Nov. 15, 1934 5 Sheets-Sheet 5 v Charles U. Savage IINVENTOR A TORNEY Patented June 11, 1940 UNITED STATES PATENT OFFICE FLUID HEAT EXCHANGE DEVICE Application November 15, 1934, Serial No. 753,166 In Canada October 11, 1934 16 Claims.

This invention relates to fluid heat exchange apparatus and it is exemplified by superheater improvements whereby an even superheat is attainable in spite of varying loads on the boiler with which the superheater is associated.

It has been recognized that convection superheaters result in varying superheat temperatures when they are operated in conjunction with a steam boiler which is subjected to varying loads. Various schemes have been proposed to overcome this defect but none has resulted in an apparatus which has been generally adopted. It is an object of this invention to provide a commercially effectiveness, and thereby keep the superheat constant as the boiler load varies.

It is also an object of the invention to effect, in a superheater boiler, a constant superheat .by co-relating changes in superheater tube effectiveness and changes in boiler rating.-

Other objects of the invention will appear as the accompanying description proceeds.

The invention will be described with reference to the accompanying drawings, in which:

Figure 1 is a View in the nature of a horizontal section through apparatus illustrating the embodiment of the invention in which the separate flat coils of superheater tubes are arranged in groups of three with the corresponding outside coils of the groups movable in unison. This view shows the actuator mechanism including two parallel and movable fluid cooled actuator tubes for moving the outside superheater coils in opposite directions from the fixed coils of the group of three.

Fig. 2 is a view in the nature of a transverse vertical section showing the manually operated device'constituting a part of the actuator mechanism. i

Fig. 3 is an elevation of the parts shown in Fig. 2.

4 is a detail horizontal section taken on the line 4-4 of Fig. 3, showing the manually operated pinion and the oppositely movable racks secured .to the fluidcooled actuator tubes.

Fig. 5 is a view in the nature of a vertical section, showing an embodiment of the invention in which the outside superheater coils of. the groups of three are moved in parallelism to the fixed coils of the groups, there being actuator mechanisms at each end of the superheater.

Fig. 6 is a view in the nature of a horizontal section of the embodiment of the invention shown in Fig. 5. Fig. '7 is a vertical section through another embodiment of the invention.

Fig. 8 is an enlarged View in the nature of a horizontal section showing the arrangement of the superheater coils in groups of three.

Fig. 9 is a detailed View in the nature of a side elevation showing the relation of the fluid cooled actuators to the lowermost loop of the superheater coils.

Fig. 1G is a detailed view indicating the manner in which the middle, or fixed superheater tubes are held in position.

11 is a detailed sectional View taken on the line lI--ll of Fig. 10.

Fig. 12 is a detailed view showing a superheater associated with the bank of steam generating. tubes.

In the drawings I have shown a superheater intended to be associated with the steam generating tubes of a water tube steam boiler. The superheater is of the convection type which has i been subject to the disadvantage that, other conditions remaining unchanged, the 'superheat varies considerably over a wide range of boiler capacities. In fact, this characteristic is so marked that damage to turbines and other equipment would be caused on account of the excessively high temperatures to which the steam would be superheated when a plain convection superheater is associated with a boiler operating over a Wide capacity range. The illustrative superheater corrects such conditions and improves superheater and turbine operation by maintaining a substantially uniform superheat over a wide range of boiler capacities. When the superheater consists of fiat coils of return bend tubes, it may be associated with a steam boiler in the manner indicated in my co-pending application #695,450, filed October 27, rest. That is, it may be located in an inter-deck 'position as indicated in Fig. 12, between vertically spaced banks of steam, generating tubes connected by headers, nipples, and .circulators into the same boiler circulation system. The flat superheater coils are preferably upright, and successive tube lengths of each coil may be joined by struts arranged throughout the coil in truss formation. This gives each coil desired stiffness and maintains the predetermined spacing of the tube lengths. Each coil may be fixed to an inlet header at one end, and an outlet header at the other end, the component successive tube lengths extending across a gas pass through which the hot gases flow across the steam generating tubes of the boiler and then across the superheater.

At least one end of each of a plurality of the.

superheater coils is shiftable transversely of the as flow and transversely of the plane of the coil to compensate for changes in boiler capacity. When the headers are fixed at one side of the gas pass, shiftable superheater coils are movably supported at the opposite side of the gas pass, and a plurality of the coils are preferably connected to actuator mechanism for simultaneous movement. This action changes the spacing of the superheatertubes.

When boiler capacity, or rating, is increased and it is desired that the superheat remain constant, the shiftable superheater coils are moved so that the coil spacing changes from a regular and uniform spacing to a grouping of the coils.

The gas lanes between the groups are thus increased, and the heating effectiveness of the coils v changed.

In one embodiment of the invention the coils are so. arranged and so connected to oppositely movable actuators that the superheater tubes are changed from a uniform spacing to a group arrangement in which each group consists of three tubes. One series of tubes moves to the right and the other series of shiftable tubes simultaneously moves toward the left. The remaining tubes are fixed against lateral novement.

Such an embodiment of the invention is indicated in Figs. 1 and 7 of the drawings. In the latter figure, the superheater coils are shown as extending from the fixed headers I40 and I42 across a gas pass 20 in which the gases flow upwardly after passing across such heating surfaces as those afforded by a bank of steam generating tubes. In this instance, the gas pass is bounded on one side by a wall, the fluid cooled tubes I60 which are preferably connected into boiler circulation. Refractory blocks 22 are preferably secured to these tubes so as to act as space closures and complete one wall of the gas pass. At the opposite side of the gas pass, refractory wall blocks 24 are secured to fluid heat exchange tubes I62 to complete the wall.

The superheater coils are preferably arranged in groups of three at maximum boiler capacities. This is clearly indicated in Fig. 1 of the drawings in which a plurality of groups of coils is clearly shown. Each group consists of a middle coil 26 positioned between shiftable coils 28 and 30. All of the coils 28 are connected to one of the actuator tubes, as for instance, tube IIB, for movement in one direction. The remaining shiftable coils are connected to the other actuator tube I I8 for simultaneous movement in an opposite direction when the heating effectiveness of the superheater coils is to be varied to afford compensation for changes in boiler capacities.

The superheater coils extend between the tubes I62 and through the wall supported by those tubes, as clearly indicated in Figs. 1 and '7. The

latter figure also indicates a manner in which the coils may be supported. At the right hand side of the superheater, brackets 38 secured to the coils extend over and are supported by brackets 36 which may support a bar 39 extending across the bracket 36. The fixed superheater coils may be supported as indicated in Figs. and 11 of the drawings. As here shown, the bracket 38 extending from a fixed coil 26 is positioned between spaced upstanding lugs 30 and 32 on the bracket 36. The bracket 38 extending from the shiftable coils are movable along toward or away from the lugs.

Corresponding shiftable coils of the separate groups of coils may be connected by pivoted lugs or links to one of the actuator tubes, the remaining superheater coils are similarly connected to the other actuator tube. These devices are indicated generally at 34 and 35 in Fig. 1 of the drawings. They may include such brackets as those indicated at 40 and M in Fig. 8, disposed between pairs of lugs 42 and 43 secured to the superheater coils.

As the boiler load increases, the superheater coils 28 and 30 are moved by the actuators from regularly spaced positions to the group arrangement indicated in Fig. 1 of the drawings. It is to be understood, of course, that these two positions are extreme control positions and that there are various intermediate positions corresponding to intermediate boiler loads.

The actuator tubes H6 and H8 each has one end connected to the inlet header I40 and the opposite end connected to the outlet header I42, as indicated in Figs. 1 and 7 of the drawings. This provides for a flow of steam or other cooled fluid through the actuator tubes to maintain them Within an allowable temperature range. Furthermore, these tubes are looped externally of the boiler casing so as to provide for the operative movements of the tubes. During such movements, the looped portions of the tubes are flexed, as will be indicated by a comparison of the full line positions and the dotted line positions in Fig. 1 of the drawings. These tubes slide through the opposite walls of the boiler at the positions indicated in Fig. l, and appropriate devices are used to prevent gas leakage to or from the gas space of the boiler, at these positions. Stuffing boxes, employing heat resisting material on their fire sides are preferable.

Fig. 7 indicates the actuator tubes H6 and H8 as located at the top of the superheater coils. This figure also shows similarly arranged tubes I30 and I32 positioned at the lower ends of the superheater coils. When these two pairs of coils are moved in unison by such control mechanism as that indicated in Figs. 2 and 3 of thedrawings, undesirable tilting or canting of the coils is prevented. These figures indicate hand control apparatus including an upright shaft I06 mounted in bearings III, H2, H3 and having fixed thereon pinions I04 meshing with confronting racks I00 and I02 secured to the actuator tubes as indicated in Fig. 1 of the drawings. When superheat is to be automatically controlled an electric motor or other appropriate driving mechanism may be substituted for the handwheel on the shaft I06, and this, or other devices appropriately governed by boiler load conditions. Steam flow indicators, temperature responsive devices, or pressure responsive instruments may be employed in controlling the automatic spacing of the superheater tubes to compensate for boiler load changes.

The ends of the superheater coils opposite the tubes I00 are supported by an arrangement of brackets similar to that supporting the coils at the tubes I60. This arrangement includes the brackets 45 and the supplementary lugs or brackthe wall formed by the blocks 24. In this situation, the end tube sections 41', 48, 49, and 50 (see Fig. '7) of the coils flex so as to permit the desired coil movements. The heat insulating material at positions 5| and 52 may be held in position by collars 53 which are maintained against the outer face of the wall blocks 24 by any appropriate means. It will also be clear from an observation of Fig. '7 of the drawings that the end tube sections 41 and 48 at the upper ends of the superheater coils are in an upright row arrangement at a position where they pass between the tubes I62. They change horizontal row arrangement at positions within. the gas pass. A similar arrangement of elements is shown at the bottoms of the superheater coils.

Tubes 60 and 6! supply saturated steam to the superheater inlet header I40 and the tubes 6| preferably have brackets 62 and 63 secured thereto for supporting the sections 41, 48, 49, and 50 of the superheater coils in their operative positions. Also, the superheater outlet header I42 is preferably located between the tubes I60 and IBI.

In the embodiment of the invention illustrated in Figs. 5 and 6, the shiftable superheater coils are maintained in parallelism during their adjustments which regulate their heating effectiveness to compensate for changes in boiler load. In this embodiment, similar coils are fixed in the manner above described and there are two pairs of actuator tubes at each side of the superheater. As illustrated in Fig. 6, one actuator mechanism includes the parallel tubes. IIS and H8 operably connected by a pinion similar to the pinion I04, mounted upon an upright shaft I20. This shaft has a lower pinion operatively associated with the actuator tubes I30 and I32 in a similar manner.

At the opposite side of the superheater indicated in Fig. 5, the upper set of actuator tubes I22 and I 26 are movable in opposite directions and in unison with a corresponding set of actuator tubes I34 and I36 by a shaft and pinion apparatus similar to that above mentioned. These two pinion shafts are intended to be operated in unison, and this may be done by the same motor or operating device so that the major parts of the superheater coils between the two upper sets of actuator tubes and the two lower sets are maintained in parallelism during the adjustments of the superheater.

All of the actuator tubes are connected into fluid circulation so that they may be protected against overheating. Fig. 6 of the drawings shows the actuator tubes I22 and I26 connected to the superheater outlet header I42 by the loops I23 and I at one side of the boiler. At the other side of the boiler they are connected to the superheater inlet header by loops I21 and I29.

1 This provides for a flow of a fluid through the coils above described. The arrangement may be suchthat alternate superheater coils are fixed, while others are movable therefrom by control mechanism similar to that described above. Also, it is within the purview of the invention that some of the coils are movable in one direction and the remaining coils movable in an opposite direction. It is also to be understood that the superheater coils may be arranged in groups of more than three coils each.

It is also to be understood that the invention is not necessarily limited in its application, to superheaters. It may be advantageously applied to other fluid heat exchange. apparatus in which spaced tubes are employed.

It is to be further understood that an arrangement of struts different from the arrangement of the struts II of Fig. '7 of the drawings may be employed.- Successive tube lengths of each superheater coil may be connected by struts arranged in truss formation. For example, the struts may be arranged in rows diverging downwardly or upwardly. Such rows of struts may be also employed in addition to the upright row of struts II. Also, the struts may be arranged so as to form, with the successive tube lengths of the superheater coils, double truss structures, in cases where the superheater coils are of considerable length. Also, the individual struts may be formed of two relatively movable interlocking parts which permit adjacent tube lengths to have relative longitudinal movement.

The motors or other operating devices which are used to move the actuator tubes may be so arranged and connected with the tubes that the tubes are always under tension while they are moving the superheater coils. This may be important to prevent buckling of the tubes, under some conditions.

It is to be further appreciated that the arrangement of the superheater coils indicated in Fig. 1 of the drawings illustrates a condition of the apparatus when an associated boiler is operating at a very high rating. At lower ratings the coils are moved out of their closely spaced, or grouped, arrangement.

In the embodiment of the invention illustrated in Fig. 5 of the drawings the shiftable superheater coils are preferably suspended by hangers I50 and I52. The coils preferably have pivoted connections with these hangers at the lower ends of the latter, and brackets I 54 and I56 support the upper ends of the hangers so that the latter are free to have limited swinging motion. These brackets are preferably welded to the wall tubes I60 and I62.

Fig. 12 shows a superheater Ill) disposed above the bank of steam generating tubes I12, and in such relationship that the furnace gases first pass over the steamgeneratilng tubes, and then over the superheater.

While the invention has been illustrated by the disclosure of a particular modification, and the description has related to such modification, it is to be appreciated that the invention is not limited thereto, but is of a scope commensurate with the scope of the sub-joined claims.

What is claimed is:

i. In superheater and boiler organization, superheater tubes, movable superheater tubes maintained .in parallelism between the fixed tubes, the tubes being so spaced that a change in spacing varies the heating efiectiveness thereof, and a fluid cooled controller connected to the movable tubes and operable to vary the tube spacing and so change the heating effectiveness of all of the tubes that a uniform superheat maybe maintained over a Wide range of boiler ratings.

2. In a superheater and boiler organization, superheatertubes so spaced that a change in spacing varies the heating effectiveness thereof, means for movably supporting some of the superheater tubes, and fluid cooled control means connected to a plurality of the movable tubes to vary the spacing of the superheater tubes while the superheater is in service and thereby modify the superheat at difierent boiler ratings, said control mechanism being so arranged that it maintains the movable tubes in parallelism.

3. In fluid heat exchange apparatus, tubular coils arranged in groups of three subject to contact with a heat exchange medium, the adjacent tubes of the adjacent coils being so spaced that a change in spacing varies the heating effectiveness thereof, oppositely movable actuators each connected to corresponding outer coils of said groups, and means for causing said actuators to be moved simultaneously in opposite directions While the ends of the coils remote from the actuators retain their original spacing.

4. In fluid heat exchange apparatus, fixed and movable tubes conducting a fiuid across a passage in which an exterior fluid at a different temperature flows transversely over the tubes, the tubes being so spaced that a change in spacing varies the heating effectiveness thereof, means connect- :ing some of the movable tubes for movement in unison in one direction away from adjacent fixed tubes, and simultaneously operable means connected to the remainder of the movable tubes for unitary movement in an opposite direction away from adjacent fixed tubes.

5. In a superheater and steam boiler organization, superheater tubes arranged in groups of three and spaced so that changes in their spacing will vary their heating effectiveness, means for maintaining the middle tubes of the groups in fixed positions, means for movably supporting the remaining tubes of the groups, a controller device connected to the exterior tubes of the groups at the right of the fixed tubes for simultaneous movement relative to the fixed tubes, a similar controller device connected to remaining movable tubes, and means for simultaneously moving said devices in opposite directions to so change the heating effectiveness of all of the tubes over a uniform superheat may be maintained over a'wide range of boiler ratings.

6. In a superheater and steam boiler organization, super-heater tubes arranged in groups of at least three tubes with each group including a fixed tube between two movable tubes and all of the tubes being so spaced that changes in their spacing will vary their heating effectiveness, a controller connecting right hand movable tubes for simultaneous movement in one direction and means connecting the remaining movable tubes to simultaneously move them in an opposite direction to prevent excessive changes in superheat as the boiler rating is varied.

'7. In fluid heat exchange apparatus, a convection section including tubes so spaced that changes in their spacing will vary their heating effectiveness, said tubes being arranged in groups of at least three tubes each with each group having a fixed tube between two movable tubes, 2. controller connecting the right hand movable tubes for simultaneous movement in one direction, and controller means connecting the remaining' movable tubes for movement simultaneously in the opposite direction whereby the heat transfer rate of said section may be varied and regulated while the apparatus is in operation.

8. In fluid heat exchange apparatus, tubes so spaced that a change in their spacing varies their heating effectiveness, means for fixing a first set of said tubes, and means for simultaneouslymoving a second set of said tubes relative to the fixed tubes and a third set of said tubes in an opposite direction in order to control the operative results of said apparatus by regulating mass fiow over said tubes.

9. In fluid heat exchange apparatus, a plurality of fiat tubular coils each consisting of a row or set of tubes lying betwen two parallel planes and connected in series, the coils being spaced from each other with gas flow lanes between the planes bounding adjacent coils, means forming a gas pass through which furnace gases flow transversely of the tubes, the flat coils being set across the gas stream so that the lanes form gas flow paths between the coils, the first tubular section of each fiat coil being contacted by the furnace gases at the same temperature but at different parts of the cross section of the entire gas stream, fixed inlet and outlet headers to which each of the coils is connected, and a controller arranged to move coils by flexing parts of the same and connected to a plurality of the coils and operating to increase the Width of some of the gas lanes and decrease the width of other gas lanes to increase or decrease the heating effectiveness of the coils and thereby control the rate of heat transferfrorn the gases to the tubes, said controller involving means maintaining parallelism of the major parts of the flow paths of the coils while the flexing takes place.

10. In a superheater associated with a boiler and heated by the same gases, spaced superheater tubes, fixed headers to which all of the superheater tubes are directly connected, and a controller for simultaneously moving some of the tubes while the headers remain fixed, said controller operating to prevent excessive changes in superheat as the boiler rating is varied, the remaining superheater tubes remaining fixed while the controller is operating.

11. In combination, a bank of tubes constituting a steam generating section of a water tube steam boiler and extending across a gas pass, a superheater located beyond said tubes relative to heating gas flow and composed of U-tubes having their inlet and outlet ends at the same side of the gas pass, means for supporting the inlet and outlet ends of the superheater tubes in uniformly spaced arrangement, a support at the other side of the gas pass, and connections between the support and some of the superheater tubes for so fiexing the latter as to vary gas flow resistance.

12. A superheater having all of its tubes uniformly spaced at one side of a gas pass, and tube flexing means connected only to some of the tubes at the other side of the pass to position the adjacent tube ends in a non-uniform spacing while the superheater is in service, said means including a movable element extending. transversely of the superheater tub-es near their movable ends.

13. In combination, a bank of tubes constituting a steam generating section of a water tube steam boiler and'extending across a gas pass, a superheater located beyond said tubes relative to heating gas flow and composed of bent tubes having their inlet and outlet ends at the same side of the gas pass, means for supporting the inlet and outlet ends of the superheater tubes in fixed relation, a movable support at the other side of the gas pass, and connections between the support and some of the superheater tubes for so flexing the connected tubes While the superheater is in service as to vary gas flow resistance and thereby maintain a uniform superheat.

14. In combination, a bank of inclined tubes constituting a steam generating section of a water tube steam boiler and extending across a gas pass, a superheater located beyond said tubes relatives to heating gas flow and composed of tubular units having their inlet and outlet ends at the same side of the gas pass, means for supporting the inlet and outlet ends of the units in uniformly spaced arrangement, a movable support at the other side of the gas pass, and connections between the support and some of the units for so flexing some of the units While the superheater is in service as to vary gas flow resistance and thereby control superheat.

15. In a convection superheater, a furnace, a row of superheater tubes extending across a gas pass, means for fixedly supporting some of said tubes at each side of the gas pass, means for fixedly supporting the remaining tubes at one side of the gas pass and movably supporting them at the opposite side of the pass, means for connecting the inlet ends of the tubes to a common fluid supply, means for connecting the outlet ends of the tubes to a common outlet, and tube flexing means connected to the movable ends of the superheater tubes and so moving them relative to the other tubes of the row as to vary the resistance to gas flow through the row and thereby control superheat.

16. A superheater having its tubes uniformly spaced across a gas pass at one position, and a superheat controller connected to the tubes at a position remote from the first position for so flexing some of the tubes while the superheater is in service as to change the spacing of the flexed tubes relative to the remainder of the tubes.

CHARLES U. SAVOYE.

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