US3215123A - Boiler construction - Google Patents

Description

NOV. 2, 1965 OLSEN BOILER CONSTRUCTION 2 Sheets-Sheet 1 Filed July 11, 1963 .1 x I l: v l K I. ha .3 n no a n :28 Iit u a a a a 8:5 v u a 1 f v u c c u 233 iwhl W nNHH .3 g 3 o n on 803 .ll v 3 no no a o no 0260 ATTUP/VE) Nov. 2, 1965 A. R. OLSEN BOILER CONSTRUCTION 2 Sheets-Sheet 2 Filed July 11, 1965 INVENTOR.

A/P/VOZD A? 0A 557V United States Patent 3,215,123 BOILER CONSTRUCTION Arnold R. Olsen, Brooklyn, N.Y., assignor to Thermal Refractories Company, North Bergen, N.J., a corporation of New Jersey Filed July 11, 1963, Ser. No. 294,304 2 Claims. (Cl. 122-478) This invention relates to boiler construction and particularly to the steam generating type which is used in marine environments.

Marine boiler construction is fairly simple, and is comprised of a combustion chamber, in which a selected fuel (oil, powdered coal, etc.) is burned to generate gases in a temperature range typically of from 2200 to 2600 F. These gases are caused to flow across upright generator tubes, which extend between a mud or water drum and a steam drum. Usually, these tubes are divided into two groups: a forward group and a rearward group, between which are positioned superheater tubes. The superheater tubes are normally held in position at right angles to the generator tubes by tube sheets. Tube sheets are relatively thin metal plates suspended within the space between the two sets or groups of generator tubes.

The tube sheets have the distressing propensity to rapidly oxidize in service, if the hot combustion gases from the combustion chamber are allowed to directly impinge upon them. Various solutions have been suggested to overcome this difiiculty, such as, for example, welding or otherwise aflixing a plurality of thin sheet metal fins to the generator tubes and superheater tubes adjacent the tube sheet, in order to divert the flow of combustion gases and prevent direct impingement on the tube sheet. As one might well imagine, whereas the tube sheet may be well protected, the fins have a tendency to erode rapidly in service. Another difliculty with the fins is the expense of installation. Further, when the fins become extensively eroded, they must be burned off before new ones can be substituted.

Refractory castable, with wire mesh reinforcing, has been suggested as a means of protecting the tube sheets. While removal is easy, the castable and wire reinforcing is rather diflicult to install, particularly in the overhead or suspended position in which the tube sheet is normally located.

Ceramic tile, usually fabricated of silicon-carbide-because of its thermal and mechanical strength and good thermal conductivity-has been suggested as a means to deflect the combustion gases from direct impingement on the tube sheets. However, even though various mating and so-called self-locking ceramic tile designs have been suggested, they have not been entirely satisfactory, since, in some instances, the tile fall from position during actual operation of the boiler.

Accordingly, it is an object of this invention to provide an improved boiler construction, which includes means to protect superheater tube sheets from direct impingement with combustion gases. It is another object of the invention to provide superheater tube sheet protection means, which are rapidly and easily installed in conventional marine boilers with a minimum of modification thereof. It is, still further, an object of the invention to provide means for turbulent deflection of the flow of combustion gases directed against generator tubes and superheater tubes in a marine boiler to promote better heat conducting relation between the gases and tubes, which means is easily installed.

Briefly, according to one aspect of the invention, I provide a plurality of self-locking pairs of deflector tile. A plurality of these pairs of tile is constructed and arranged to be positioned in stacked relation between an adjacent pair of closely spaced, parallel generator tubes. The

lowermost tile of the lowermost pair of self-locking tile has a notch formed in it arranged to loosely substantially entirely encompass or be positioned over a smaller, but complementary shaped lug welded or otherwise affixed to one of the pair of generator tubes between which the tile are stacked. When I say lowermost tile of the lowermost pair of self-locking tile, I mean to describe that the tile having the notch formed in it and which, when it is itself suspended by the lug, supports its mate to form a self-locking pair.

Further details of construction, and other objects and advantages of boiler construction according to this invention, will be readily apparent to those skilled in the art from the following detailed description, with reference to the drawings; in which like reference numerals are used to designate like parts in the several views. In these drawings:

FIG. 1 is a fragmentary perspective view, partially broken away and in partial section, to better show internal arrangement of parts, of marine boiler construction having the benefits of this invention;

FIG. 2 is a fragmentary side elevation of a portion of the arrangement of FIG. 1;

FIG. 3 is the top elevation of the arrangement of FIG. 2;

FIG. 4 is a fragmentary end detail of the arrangement of FIG. 2;

FIG. 5 is a fragmentary side elevation of the arrangement of FIG. 2; and

FIG. 6 is a fragmentary schematic view of a composite installation using the teachings of this invention.

Before describing the drawings in detail, it should be understood they are but exemplary of practices according to this invention; and the improvements disclosed and claimed herein should not be considered as limited to the apparatus embodiment shown in the drawings but, rather, the true spirit and scope of the invention should be as defined in the hereafter appended claims.

Particularly in large marine vessels, it is common to use a steam generating boiler as a portion of the power plant thereof. These boilers are most generally of the water tube variety, in which the inner walls of a combustion chamber are lined with a plurality of tubes; and, further, include banks of tubes of various special constructions arranged for contact with hot products of combustion, to heat water passing through them, to thereby generate steam. The fuel for these boilers is, conventionally, a pulverized carbonaceous material, such as coal, or oil. In FIG. 1, I have shown what can be considered an exemplary boiler construction. It includes a main combustion chamber 10. A front wall 11 has a burner port 12 openin g therethrough for the obvious purpose of entering the fuel into the combustion chamber.

A sidewall, rearwall and roof are partially shown in FIG. 1. The sidewall includes the outer sheet steel skin 15, having a layer of refractory castable 16 along the inner surface thereof. Block insulation 17 is positioned over the castable 15. Refractory tile 18 face the block insulation and are the inner wall of the combustion chamber. The roof is similarly constructed and includes the outer sheet metal shell or skin 20, the inner layer of castable 21, block insulation 22, and the inner face of refractory tile 23. The rearwall, which is faced with refractory tile 24, and the other sidewall, which is not shown in the drawings, are of construction similar to the other walls. The floor of the burner chamber is comprised of an outer metal skin 25, castable 26, block insulation 27, refractory brick 28 and a refractory monolith floor 29. This moonlith floor can be, for example, a sodium silicate bonded periclase grain.

Within chamber 10, to one side of the burner port 12, are positioned a water drum 30 and a steam drum 31.

The water drum 30 is supported on the floor of the combustion chamber, and the steam drum 31 is shown supported in or by the roof. A plurality of generator tubes opens between the water tank 30 and steam tank 31. These tubes are, generally, divided into the two groups 32 and 33. The forward group 32, under stabilized operating conditions, generates steam at a temperature of about 450 F. and at about 600 psi. pressure. This steam is passed upwardly through the pool of water 34 in the bottom of the steam drum 31. Steam evolving from this body of water 34, is passed through a header (not shown) opening from the rear of the steam drum to flow into and through the substantially horizontally disposed banks of superheater tubes 35. These superheater tubes 35 are maintained as bundles, and suspended in position by tube support sheet 36. The steam, after passing through the superheater tubes 35, is on the order of about 800 F. (The above temperatures and pressures are, of course, exemplary and are, generally, indicative of conditions found when the combustion gases are between 2200 and 2600 F., as mentioned above.) The rear group of generator tubes 33 conduct water downwardly from the pool 34 to the water drum 30.

The superheated steam from superheater tubes 35 is conducted to a turbine or reciprocal engine installation (not shown) in a known manner to propel a vessel or the like in Which the boiler is installed. The particular type of superheater tubes 35, shown in the drawings, are termed hairpin tubes in the art.

It is conventional to run tubes through the walls behind the refractory face tile, but we have not shown them in the drawings to maintain simplicity herein.

As mentioned above, the tube sheet 36 is normally a plate or sheet of metal and is rapidly oxidized when it is subjected to direct impingement by gases exiting from the combustion chamber 10. The water or steam which passes through the generator tubes and superheater tubes protects them from this rapid oxidation and, thus, the tube support sheet is the weakest point in the tube system. To protect the tube sheet 36 from direct impingement, I suspend a plurality of pairs of interlocking deflector tile 40 in stacked relation to each other. These tile are arranged for mounting between adjacent parallel pairs of forward generator tubes 32. When so mounted, they deflect the gases traveling from the combustion chamber and prevent direct impingement thereby on the tube support sheet 36. More detail of deflector tile construction and relation with the generator tubes 32 in an installation according to this invention is most clearly seen by reference to FIGS. 2 through 5. The tile of a self-locking pair of tile 40 are actually two identical tile, one of which has been inverted so respective biased or sloped surfaces 41 abut each other. The outer edge or face of each of the tile 40 is grooved its entire length to provide an arcuate longitudinal depression 42, capable of partially encompassing in face to face relation at least a portion of the outer surface of a generator tube 32. As is seen most clearly in FIG. 2, from the rear, 21 pair of tile show a rectangular configuration with a sloped cut through it. This sloped cut is the interface of abutting sloped faces 41. The forward face of each tile of a pair of tile is outwardly curved, as at 43, to together form a smooth convex surface arranged to deflect impinging gases towards and against the generator tubes between which the pair of tile are placed.

Upper and lower surfaces of the tile which make up the pairs of tile are preferably flat so they may contiguously lie in stacked relation on or beneath other pairs of tile, as is shown in FIG. 2.

The lowermost tile 40A of a stacked plurality of selflockin-g pairs of deflector tile is notched as at 50. The notch 50 is sufficiently large as to completely cover, in loose relation, a lug 51, which is welded or otherwise affixed to the inner or side face of one of the pair of generator tubes 32 between which a stacked plurality of the self-locking tile are to be positioned. When I say completely encompass, in referring to the size of the notch 50 relative to the lug 51, I mean it is of sufiicient depth to prevent direct impingement on a contained lug by combustion gases traveling towards them. The bottom of the notch is, of course, open; although, it may be closed with a conventional silicon carbide type mortar, if one so desires. The notch and lug have vertical bisectors lying in a plane common to that of a vertical bisector of the generator tube to which the lug is attached.

The foregoing construction, described relative to FIGS. 2 through 5, can be seen to provide a rapidly and easily installed arrangement for preventing direct impingement of high temperature combustion gases of such as tube sheet 36. My construction has still other advantages and uses. For example, referring to FIG. 6, I show its use to fabricate suspended bafiies for convection control. The parts I have shown in FIG. 6 are, generally, the same as those shown in FIGS. 1 through 5; but I have appended the letter B to similar parts, in order to avoid confu sion. For example, the water drum 30B and steam drum 31B have a plurality of generator tubes opening between them, one of which is indicated at 32B in FIG. 6. A plurality of the self-locking tile is shown in position to form two suspended baffles. The first, at 58, includes a plurality of interlocking tile 40B; the lowermost tile 40AB of the series of the interlocking tile 40B is shown to include a notch 50B capable of loosely encompassing the lug 51B which is welded to the generator tube 32B. Silicon carbide cement is indicated at 52 to seal the space between the steam drum 31B and the baflie at 58. This baffle construction is used to prevent short circuiting of combustion gases closely adjacent the steam drum. Lacking such a baffle, the gases, instead of traveling over the mass of tubes which are positioned lower, may tend to rush upwards across the roof and below the steam drum 31B.

A second baffle installation is shown at 53, which bafile installation is comprised, again, of a plurality of self-locking tile 40B, the lowermost of which 40AB includes a notch 50B of sufficient dimension as to encompass a lug 51B. This baflie is supported a distance above the water drum 30B and, further, assists in inducing turbulent counterflowing of combustion gases to assure intimate heat conducting contact between the generator tubes and superheater tubes.

The lug 51B, or the lug 51, is so positioned as to allow insertion of a whole number multiple of a plurality of pairs of the self-locking tile above the lug and below the steam drum. To do this, one must allow for space to remain above the stacked plurality of deflector tile. If this space is not allowed for, considerable difiiculty will be had when one attempts to set the last pair of tile above the plurality of previously positioned tile and below the steam drum. For example, considering the individual tile to be on the order of 4" in height, I would suggest leaving about three inches. A pair of tile can then be sawed crosswise in half and inserted and the remaining space filled with a refractory mortar such as silicon carbide mortar, or else the entire space can be filled up with silicon carbide mortar.

As to an exemplary suggested vertical dimension for the composite boiler baffle, described above, it may run from 10 to about 40% of the total vertical distance between the water drum 30 and steam drum 31. The precise dimensions are, of course, very flexible.

Having thus described the invention in detail and with suflicient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims.

I claim:

1. The combination with a boiler having a combustion chamber, an upper steam drum and a lower water drum with a plurality of upright generator tubes running between the steam drum and water drum, and a group of superheater tubes, said generator tubes divided into at least two upright groups to define a space therebetween transversely Within which space is suspended a plurality of superheater tubes, said superheater tubes at least partially supported in position by at least one tube support sheet which is transverse of the superheater tubes, said tube support sheet being a relatively thin metal plate extending downward in a space between said two upright groups, of a plurality of self-locking pairs of deflector tile positioned in stacked relation between at least one adjacent pair of the generator tubes, and means suspending the stacked pairs of selflocking deflector tile between adjacent pair of generator tubes in position to completely cover the edge of said support sheet normally exposed to the flow of combustion gases to deflect said combustion gases from direct impingement on the superheater tube support sheet, said means suspending the tile comprised of lug means affixed to the exterior surface of one of the generator tubes and a slot formed in the lowermost tile of the lowermost pair of self-locking tile, said notch encompassing said lug in loose fitting relation and to a suflicient extent to prevent impingement of combustion gases on said lug.

2. The combination of claim 1 in which the tile are silicon carbide tile.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Publication: Refractories, published by General Refractories Co., Philadelphia, Pa. Copyright, pages 23 to 25.

JAMES W. WESTHAVER, Primary Examiner.

KENNETH W. SPRAGUE, PERCY L. PATRICK,

FREDERICK L. MATTESON, JR., Examiners.

Claims (1)

1. THE COMBINATION WITH A BOILER HAVING A COMBUSTION CHAMBER, AN UPPER STEAM DRUM AND A LOWER WATER DRUM WITH A PLURALITY OF UPRIGHT GENERATOR TUBES RUNNING BETWEEN THE STEAM DRUM AND WATER DRUM, AND A GRUP OF SUPERHEATER TUBES, SAID GENERATOR TUBES DIVIDED INTO AT LEAST TWO UPRIGHT GROUPS TO DEFINE A SPACE THEREBETWEN TRANSVERSELY WITHIN WHICH SPACE IS SUSPENDED A PLURALITY OF SUPERHEATER TUBES, SAID SUPERHEATER TUBES AT LEAST PARTIALLY SUPPORTED IN POSITION BY AT LEAST ONE TUBE SUPPORT SHEET WHICH IS TRANSVERSE OF THE SUPERHEATER TUBES, SAID TUBE SUPPORT SHEET BEING A RELATIVELY THIN METAL PLATE EXTENDING DOWNWARD IN A SPACE BETWEEN SAID TWO UPRIGHTGROUPS, OF A PLURALITY OF SELF-LOCKING PAIRS OF DEFLECTOR TILE POSITIONED IN STACKED RELATION BETWEEN AT LEAST ONE ADJACENT PAIR OF THE GENERATOR TUBES, AND MEANS SUSPENDING THE STACKED PAIRS OF SELFLOCKING DEFLECTOR TILE BETWEEN ADJACENT PAIR OF GENERATOR TUBES IN POSITION TO COMPLETELY COVER THE EDGE OF SAID SUPPORT SHEET NORMALLY EXPOSED TO THE FLOW OF COMBUSTION GASES TO DEFLECT SAID COMBUSTION GASES FROM DIRECT IMPINGEMENT ON THE SUPERHEATER TUBE SUPPORT SHEET, SAID MEANS SUSPENDING THE TITLE COMPRISED OF LUG MEANS AFFIXED

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