US1950043A - Boiler - Google Patents

Description

March 6, 1934. A, U, WETHERBEE 1,950,043

BOILER Filed Aug. 4, 1952 5 sheets-sheet 1 March 6, 1934. A U WETHERBEE 1,950,043

BOILER Filed Aug. 4, 1932 5 Sheets-Sheet 2 9 J d /7 a C a ,aff/f: w: :QQ/N

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March 6, 1934. A. u. WETHERBEE 1,950,043

BOILER Filed Aug. 4, 19252 5 Sheets-Sheet 4.

March 6, 1934. A u. WETHERBEE BOILER Filed Aug. 4, 1932 5 Sheets-Shea?I 5 Patented Mar.' 6, 1934 UNITED STATES PATENT OFFICE 12 Claims.

This invention relates to boilers,'and more particularly to boilers employing a plurality of drums connected in a ring circuit.

I have illustrated my invention, by way of example, as applied to a boiler comprising three drums connected in a ring circuit. Though my invention is particularly adapted for a three drum boiler, it may be applied, in its broader aspects, to boilers using more than three drums as will be understood'by those skilled in the art, and I do not, therefore, limit my invention to three drum boilers only.

The primary object of my invention is to provide a boiler of comparatively simple and inexpensive construction which possesses high efficiency. More specifically, the main object of my invention is the provision of a boiler having a large heat absorbing area and'rapid circulation, to the end of high heat absorbing capacity. Further objects and advantages of my invention will appear from the detail description.

In the drawingsz- Figure 1 is a vertical central sectional view of a boiler constructed in accordance with my invention as applied, taken from front to back of the casing, with parts in elevation;

Figure 2 is a view similar to Figure 1, showing a modified form of my invention;

Figure 3 is a view similar to Figure 1, showing a second modified form of my invention;

Figure 4 is a view similar to Figure 1, showing a third modified form of my invention;

Figure 5 is a view similar to Figure 1, showing a fourth modified form of my invention;

Figure 6 is a section taken substantially on line 8 6 of Figure 1.

In Figure 1 of the drawings Ihave illustrated my boiler as mounted in a casing which is reenforced by a frame 2 formed of structural steel. The frame and the casing are, in general, of known construction and need not be illustrated nor described in detail. The casing includes a furnace 3 at the rear of which is a back wall 4, the space 5 above the grate 6 constituting the combus- 45 tion space of the furnace.

The boiler is mounted in casing l at the upper portion thereof. 4Frame 2 comprises two main side supporting beams 7 of I cross section. The boiler comprises an upper steam and water drum 5c 8 disposed adjacent the back wall of the casing, a. lower mud drum 9 also disposed adjacent the back wall of the casing, and a water drum 10 disposed between drums 8 and 9 and at the front wall of the casing. These drums are connected te together in a ring circuit by banks of tubes 11,

12 and 13. 'I'he tubes are bent and enter the drums radially thereof, in a manner well known in the art. Drum 8 is provided with a steam nozzle 14. This drum may also be provided with a dry pipe, suitable battles adjacent to the dry pipe, and a feed water pipe extending along the drum 8 at the lower portion thereof for supplying feed water to the drum in a known manner; all known in the art. The tubes 11 constitute the downcomers, certain tubes conducting more feed water than other tubes, the tubes 12 constitute the upgoers for the upward fiow of steam and water therethrough at relatively high speed, and the bank of tubes 13 also constitute upflow tubes for conducting the steam and water from drum l0 to drum 8 in which the steam is liberated.

The water drum 10 is anchored to the under faces of beams 7 in a suitable manner, as by means of brackets 15 suitably secured to the .heads of the drum, these brackets being riveted or otherwise suitably secured to beams 7. Drum 8 is slidably mounted, at each end and in a suitable manner, upon the upper faces of beams 7.

An arch 16 ext-ends over the upper portion of the drum 8 and is provided with an opening to 80 accommodate the nozzle y14, this opening being of appreciably greater extent than the nozzle to permit the sliding movement of drum 8 referred to. The top of the casing is closed by a suitable roof structure 17.

A baffle 18 formed of slabs or tiles of suitable refractory material, is supported upon the upper tubes of the bank of tubes 12 and extends up'- Wardly from the mud drum 9 for approximately one-half the length of the tubes. An upper baie 19 extends across the bank of tubes 13 from the lower row of tubes thereof to the next to the top row of tubes, this bale being inclined upwardly and forwardly of the casing. An angle bar 20 is secured to the lower row of tubes of the bank 13 by U-bolts 21,v or in any other suitable man ner. The vertical flange of this bar fits into a groove 22 formed in the upper edge of a vertical y baie 23, the lower edge of which is rabbeted and seats upon the upper edge of baiiie 18. The up- 10c per edge of baiiie 23 is disposed closely adjacent the lower edge of bailie 19, so as to form a closure therewith. Groove 22 is of appreciably greater width and depth than the vertical ange or arm of bar 20 thus permitting movement of bae 23 105 relative to the bar. This is of importance as permitting movement of baiiie 23 in accordance with expansion and contraction of the bane 18 and tubes l2, While also permitting relative move= ment between this baiie and the heme l@ and tubes 13. In this manner I avoid subjecting the bailie 23 to stresses such as would tend quickly to destroy the baffle. I also provide simple and efficient means for normally holding the baiiie 23 in position while permitting ready removal and replacement thereof as required. This baffle may be constructed of slabs or tiles of proper width fitted end to end across the casing to form a suitable barrier or baffle, as is known in the art in the constructionof baffles and similar structures.

The casing further comprises a fire wall 25 disposed adjacent the back of the casing. An arch 26 is disposed between the-back wall and the iire wall and a series o f tubes, one of which is shown at 27, extend through this arch, these tubes connecting the mud drum 9 to a. header 28 at the top of front wall 29 of the furnace. A series of tubes 30 connect header 28 to water drum 10, the header 28 being at a lower level than the water drum and the tubes 30 being inclined upwardly and rearwardly of the casing. The tubes 30 alternate with the tubes 27 and provide a supporting structure for the roof 31 of the furnace, the furnace roof being thus water cooled. The tubes 27 form a slag screen which extends above the fire box in the furnace.

A baille 32 extends from the arch structure 26 upwardly and forwardly of the casing to within a short distance of water drum 10. A baille 33 extends downwardly from the drum 8 between certain of the tubes 11. This baffle 33 is suitably secured to certain of the tubes 11 by U-bolts 34 or in any other suitable manner. 'I'he hot products of combustion are -thus caused to pass downwardly along the tubes 11 and across the lower portion of these tubes and then upwardly along the remaining tubes 11 to the'chimney or outlet,` opening 24, this opening being controlled by a suitable valve or damper 24a.

The hot products of combustion from the furnace flow rearwardly and then upwardly along and across the lower bank of tubes and are then deflected by the baffle 19 forwardly of the casing across the tubes 13, these gases then passing through the space between baffle 19 and roof 17 and iiowing downwardly acrossl tubes 13 in a reverse direction, after which the gases flow across and along the tubes 11 and-thence to the chimney opening or outlet 24 of the furnace.

Mud drum 9 extends into a recess at the upper edge of fire wall 25, the space between this wall and the drum being sealed by a packing 35 of suitable material, such as asbestos. The ends of this drum may extend through suitable openings in the sides of the casing, as may the ends of drum 8. In such case packing rings of suitable refractory material maybe disposed about the ends of the drums to provide closures between the same and the casing walls. Preferably, asbestos in a highly fibrous condition is employed for effecting these closures, though any other suitable material which possesses sufllcient resiliency to permit of the desired movement of drums 8 and 9 may be used.

The tubesl 27 and 30 and the header 28 are included in the circulating system of the boiler and the drum 8 is mounted for sliding movement on the beams 7 of the frame, mud drum 9 being tube suspended and free for movement to accommodate expansion and contraction of the tubes, as stated.

It is particularly pointed out that in the boiler construction illustrated, water drum 10 is anchored to the undersides of beam 7 and the water and steam drum 8 is slidably mounted upon the upper sides of these beams, the mud drum 9 being tube suspended from the drums 8 and 10 and being free for movement to accommodate expansion and contraction of the tubes 11 and 12. This provides a simple but highly efficient construction of boiler in which both the water drum and the water and steam drum are effectively supported in such manner as to prevent any tendency toward tipping of the boiler structure while permitting expansion and contraction of the tubes 13, dueto the sliding movement of drum 8, as well as the tubes 11 and 12. In this manner I eliminate undesirable stresses due to expansion and contraction of the tubes, such as would be apt to cause injury to either the tubes or the drums if the drum 8 were not mounted for sliding movement and the mud drum 9 were not capable of movement to accommodate expansion and contraction of tubes 11 and 12.

In Figure 2 I have illustrated my lboiler as used with a furnace employing gas, oil or pulverized coal as fuel, and the construction of the casing 36 is modified accordingly. A header 37 extends across the back of the furnace and is connected by tubes 38 to mud drum 9. Tubes 38 alternate with tubes 39 which connect the header to drum 10 and are inclined at an inclination upwardly -and forwardly of the casing, these tubes 39 extending over the combustion space of the furnace and constituting a slag screen. A wall 40 extends across the casing adjacent and in front of mud drum 9, and a baille 41, which rests upon the lower portions of tubes 39 and constitutes a fire arch, extends from wall 40 to theback wall of the casing. Tubes 12a, disposed in a row above the bank of tubes 13 and adjacent roof 17a, connect drum 10 to drum 9 and support roof 17a. With the exceptions noted, the boiler of Figure 2 is, in general, similar to that of Figure 1.

In the modified form of Figure 3, tubes 38a alternatel with tubes 39, and connect the mud drum 9 to header 37. In addition, I provide tubes 42, which may correspond in number to tubes 38a and connect the mud drum to header 37 at the top thereof. A wall 43 extends across the casing adjacent and in front of drum 9, there being a baille member 44 supported upon tubes 38a and 39, which baiiie member extends upwardly about the front face of wall 43 with the inner ends of tubes 38a being curved upwardly about the front end of this baffle. The tubes 38a and 42 provide, with drum 9 and header 37, a local circuit effective for heating theV water in the mud drum.

The boiler shown in Figure 4 is the same as that of Figure 2, except that alternate tubes 12b of the bottom row of the lower bank of tubes are bent downwardly so as to provide an upper and supplemental slag screen. If desired, and under certain conditions, header 37 and tubes 38 and 39 may be omitted.

The modified form illustrated in Figure 5 may be considered as a combination of the forms shown in Figures 1 and 3. In this form, tubes 39a connect back header 37a to front header 28a tubes 38h, which alternate with tubes 39a, connect header 37a to drum 9, and tubes 42a connect mud drum 9 to header 37a and serve a:

downcomers.

In all of the forms of my boiler illustrated, thu slag screen extends over the combustion space o the furnace. The tubes of this screen material ly increase the surface area exposed to the ho gases of combustion, which increases the hea absorbing capacity of the boiler, resulting in in creased efliciency. They also facilitate the obtaining of long ame travel, which is desirable.

In the construction of boiler in Figures 1 to 5, inclusive, the steam and water drum 8 is of appreciably greater diameter than the mud drum 9, and the mud drum and the water drum are of substantially the same ldiameter. It is the present practice in boiler construction to have the upper water and steam drum of the same diameter as the mud drum. I have found, however, that by increasing the diameter of the steam and water drum I obtain certain important advantages over the present practice. In practice, I prefer to have the water and steam drum approximately one-third greater in diameter than the mud drum 9. This relatively great diameter of the steam and water drum has numerous advantages. It provides greater water and steam storage space than heretofore, and also provides an increased steam liberating area avoiding splashing in the steam and water drum. Another important advantage of employing the steam and water drum of relatively great diameter is that it provides greater water endurance surface than is available in boilers constructed in accprdance with the present practice, maintaining the water more nearly at a constant level. This is an important consideration in the operation of boilers. Also, with a large drum the tubes are less liable to be uncovered due to variations in water level. By water endurance surface I refer to the net area of the actual contact surface between the water and the steam space in the boiler, which serves as the measure of the ability of a boiler to deliver steam without dropping its water level if boiler feeding is stopped.

In the several forms of myinvention illustrated the setting or casing, including the furnace, has been illustrated as of more or less conventional construction. It will be understood, however, that the construction of the setting or casing may be varied within wide limits without departing from my invention which resides primarily in the construction and arrangement of the boiler drums and tubes and associated parts. The mud drum 9 is provided with a blow-off pipe 45 for blowing mud and sediment out of this drum in a known manner.

As above indicated and as will be understood by those skilled in the art, changes in construction and arrangement of parts of my invention may be resorted to without departing from the eld and scope of the same, and I intend to include all such variations, as fall within the scope of the appended claims, in this application in which the preferred forms only of my invention are disclosed.`

This application is a continuation in part of my copending application for Three drum boiler, Serial No. 342,506, filed February 25, 1929.

What I claim iszl. In combination, a casing comprising a furnace provided with a roof and extending forwardly from the front wall of the casing and opening into the same, an upper steam and water drum adjacent the rear of the casing, a water drum adjacent the front of the casing and below the steam and water drum, a lower mud drum, banks of tubes connecting the drums in a ring circuit, a header adjacent the front wall of the furnace, tubes connecting the header to the water drum and supporting the roof of the furnace, and tubes connecting the header to the mud drum and extending over the combustion space of the furnace.

2. In combination, a casing comprising a furnace provided with a roof, an upper steam and water drum adjacent the rear of the casing, a water drum adjacent the front of the casing and below the steam and water drum, a lower mud drum, banks of tubes connecting the drums in a ring circuit, a header adjacent the front wall of the casing,- tubes connecting the header to the water drum and supporting the roof of the furnace, and tubes connecting the header to the mud drum and extending over the combustion space of the furnace.

3. In combination, a casing comprising a furnace extending forwardly from the front wall of the casing and opening into the same, an upper steam and water drum adjacent the rear of the casing, a drum adjacent the front of the casing and below the steam and water drum, a lower mud drum, bank of tubes connecting the drums, a header adjacent the front wall of the furnace, tubes connecting the header to the water drum, and tubes connecting the mud drum to the header and extending over the combustion space of the furnace.

4. In combination, a casing comprising a furnace, an upper steam and water drum adjacent one end of the casing, two lower drums one of which is a mud drum and the other of which is la water drum, the water drum being disposed between the mud drum and the steam and water drum and adjacent the other end of the casing, the mud drum being disposed adjacent the first mentioned end of the casing, banks of tubes connecting the drums, a header at one end of the casing, tubes connecting the header to one of the lower drums, and tubes connecting the header to the other lower drum and extending over the furnace, the last mentioned tubes being disposed below the lower of said banks of tubes a distance greater than the vertical distance between adjacent tubes of said lower bank and providing a slag screen over the furnace.

5. In combination, a casing comprising a furnace, an upper steam and water drum adjacent one end of the casing, two lower drums one of which is a mud drum and the other of which is a water drum, the water drum being disposed between the mud drum and the steam and water drum and adjacent the other end of the casing, the mud drum being disposed adjacent the rst mentioned end of the casing, banks of tubes connecting the drums, a header at one end of the casing and adjacent one of said lower drums, tubes connecting the header to .the lower drum adjacent thereto and extending over the furnace, and tubes connecting the header to the other lower drum and extending over the furnace, the last mentioned tubes being disposed below the lower of said banks of tubes a distance greater than the vertical distance between adjacent tubes of said lowerbank and providing a slag screen over the furnace.

6. In combination, a casing comprising a furnace, two drums disposed one below the other and adjacent an end of the casing, a third drum adjacent the other end of the casing, banks of tubes connecting the drums, a header at the jacent the other end of the casing,

nace, an upper steam and water drum adjacent the rear of the casing, a drum adjacent the front of the casing and below the steam and water drum, a lower mud drum, banks of tubes connecting the drums in a ring circuit, a header adjacent the back wall of the casing, tubes connecting the header to the mud drum and extending over the combustion space of the furnace. and tubes connecting the header to the water drum and extending over the combustion space of the furnace.

8. In combination, a casing comprising a furnace, an upper steam and water drum adjacent the rear of the casing, a water drum adjacent the front of the casing and below the steam and water drum, a lower mud drum, banks of tubes connecting the drums in a ring circuit, a header adjacent the back wall of the casing, tubes connecting the header to the water drum and extending over the combustion space of the furnace, a first series of tubes connecting the mud drum to the header, and a second series of tubes connecting the header to the mud drum, the two said series of tubes and the header and the mud drum formv ingv a local flow circuit. 9. In combination, ahcasing comprising a furnace, two drums disposed one below the other and adjacent an end of the casing, a third drum adbanks of tubes connecting the drums, a header at the first mentioned end of the casing, tubes connecting the header to said third drum and extending over the combustion space of the furnace, a lower series of tubes alternating with the tubes extending over the combustion space and connecting the header to the lower one of said two drums, and an upper series of tubes connecting the header to said lower drum.

10. In combination, a casingcomprising a furnace, two drums disposed one below the other and adjacent an end wall of the casing, a third drum adjacent the other end of the casing, banks oftubes connecting the drums, a header at the first mentioned end of the casing, a wall within and extending across the casing adjacent the lower one of said two drums, tubes connecting the header to said lower drum, tubes connecting the header to said third drum and extending over the combustion space of the furnace, and a baffle member extending between said wall and the adjacent end wall of the casing, said member being supported by said tubes and constituting therewith a re arch.

11. In combination, a casing comprising a furnace, two drums disposed one below the other and adjacent an end wall of the casing, a third drum adjacent the other end of the casing, banks of tubes connecting the drums, a header at the rst mentioned end of the casing, a lower series of tubes connecting the header to the lower one of said two drums, an upper series of tubes connecting the header to said lower drum, a wall within and extending across the casing adjacent the lower drum, and a baille member extending between said wall and the adjacent end wall of the casing, said member being supported by said lower series of tubes and constituting therewith a fire arch.

12. In combination, a casing comprising a furnace, two drums and adjacent an end of the casing, a third drum adjacent the other end of the casing, banks of tubes connecting the drums, headers at each end of the casing, tubes connecting the respective headers to the drums adjacent thereto, and tubes connecting the headers and extending over the combustion space of the furnace.

yASHUiEt U. WETHERBEE.

disposed one below the other.

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