US3261328A

US3261328A - Boiler construction

Info

Publication number: US3261328A
Application number: US363382A
Authority: US
Inventors: Johannes G Mueller
Original assignee: Weil McLain Co Inc
Current assignee: Marley Wylain Co LLC
Priority date: 1964-04-29
Filing date: 1964-04-29
Publication date: 1966-07-19
Anticipated expiration: 1983-07-19

Description

July 19, 1966 .1. G. MUELLER BOILER CONSTRUCTION 2 SheetsSheet 1 Filed April 29, 1964 INVENTOR- JOHANNES G. MUELLER Voii$m ATTYs,

July 19, 1966 J, MUELLER 3,261,328

BOILER CONSTRUCTION Filed April 29, 1964 2 Sheets-Sheet 2 A h INVENTOR JOHANNES G-MUELLER United States Patent 3,261,328 BOILER CONSTRUCTION Johannes G. Mueller, Michigan City, Ind., assignor to Weil-McLain Company, Inc., Michigan City, Ind., a corporation of Indiana Filed Apr. 29, 1964, Ser. No. 363,382 Claims. (Cl. 122225) The present invention relates to heating equipment and, more specifically, to a boiler construction utilizable with forced or natural draft firing. While not so limited in its uses, the present invention finds particularly advantageous application in connection with sectional type boilers made up of a plurality of individual rectangular shaped sections which are fastened together mechanically and which define a firebox located centrally in the lower portion thereof.

In general, this invention is concerned with improvements in the internal construction of multiple pass boilers which allow for an increase in the capacity of the boilers, assuming the same size fireboxes as with previous boiler constructions and assuming the same pressure loss or forced draft loss exists throughout the boilers. In previous boiler constructions having multiple passes, a flue gas outlet has been provided in the rear of the boiler and the flue gas flow pattern results in an accumulation of the total flue gas volume in the last pass before the outlet. Since the same boiler sections are used for a series of boilers, this requires that the cross-sectional area of the last pass be dimensioned in accordance with the maximum total flue gas volume for the largest boiler in a series. As

a result, the last pass is oversized for the smallest boiler in the series, resulting in uneconomical operation thereof due to the slow gas velocity therethrough.

A primary object of the present invention is to provide improved internal construction for boilers resulting in an increase in capacity for the same size boiler. A related object is to provide improved internal construction for boilers which results in automatic, uniform distribution of flue gas along the entire length of the boiler. Additionally, an object is to provide a more economical boiler.

A more specific object is to provide an improved boiler construction wherein the flue gas outlet is provided on the top of the boiler near the center thereof and adequate turn-around passages are provided at both the front and rear of the boiler whereby the flue gas flow is divided into two paths resulting in uniform distribution thereof throughout the boiler. A consequential object is to provide such an improved boiler construction wherein the cross-sectional area of the flue gas passes may be reduced to one-half the cross-sectional area for corresponding flue gas passes in previously utilized boiler sections. It follows that an object is to provide an improved boiler construction characterized in that the capacity of a boiler having the same firebox as previous boilers may be doubled, assuming the same pressure loss or forced draft loss throughout the boiler.

A general object of the present invention is to provide a new and improved sectional boiler wherein the construction thereof facilitates casting, handling, assembling, shipping and the like. A related object is to provide a sectional boiler which is more compact and requires less material for the same boiler output as compared to previous boilers.

Further, a general object is to provide a new and improved sectional boiler characterized in its increased efliciency of operation.

Other objects and advantages of the present invention will become apparent as the following description proceeds, taken in conjunction with the drawings, in which:

FIGURE 1 is a perspective view of an erected exem- 'plar'y sectional-type boiler embodying the present inven- Patented July 19, 1966 tion wherein parts are broken away to illustrate the internal construction details of the boiler;

FIGS. 2, 3 and 4 are front elevated views of the front, intermediate and back sections, respectively, of boiler sections utilizable in FIG. 1 which are constructed in accordance with the teachings of the present invention;

FIG. 5 is a front elevated view of a modified intermediate section for the boiler in FIG. 1 which is constructed in accordance with the teachings of the present invention; and

FIG. 6 is a partially cutaway view illustrating the crosssectional relationship of two of the boiler sections illustrate-d in FIG. 1 having sealing interposed therebetween.

While the invention has been described in connection with certain preferred embodiments, it is to be understood that the invention is'not to be limited to the disclosed embodiments but, on the contrary, the invention is intended to cover the various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

For the purpose of describing a preferred environment for the present invention, it is shown embodied in a sectional-type boiler, that is, a boiler unit made up of a plurality of individual rectangular-shaped sections which are fastened together by mechanical devices and which define a firebox located centrally in the lower portion thereof.

Referring to the drawings and more specifically to FIGS. 1-4, a sectional-type boiler 10, wherein the present invention is incorporated, is illustrated having the front portion thereof removed. In the illustrated embodiment, rectangular boiler sections 11 are erected so as to define a firebox 12 located centrally thereof in the lowermost portion. For the purpose of firing the boiler, a forced draft type burner or a natural draft fired burner (not shown) may be mounted in place on the front of the boiler adjacent the firebox 12. Hot flue gases are produced by a flame in the firebox and the flue gases pass through the boiler to a vertical smoke collar or flue gas outlet 13 which serves to lead the gases to a chimney.

For the purpose of generating steam or supplying heated water to a hot water system, water is circulated through an internal header 16 and through water passages 17 formed by coring the casting for each boiler section. The internal header 16 is formed by connecting upper nipple openings 18 by slipped nipples 19, and a pipe (not shown) which is connected to the header extends to the heating system. As will be observed from a careful examination of FIG. 1, the individual sections of the boiler are cast so as to form the water passages 17 within each individual section and the firebox 12 is entirely surrounded by such water passages, i.e., the firebox is surrounded by water backed surfaces. Since the firebox is surrounded by water backed surfaces, a combustion chamber is not required as would otherwise be required. Accordingly, this boiler construction allows for reduction in the boiler height and thus allows for a more compact boiler. This construction also reduces heat loss through the bottom of the boiler.

The boiler sections are also constructed so as to provide vertical passages or uptakes 21 between adjacent boiler sections. For this purpose, each side of the individual boiler sections is formed so that, when adjacent sections are connected together, vertical uptake passages 21 are left between the sections and both sides of the boiler. As will become apparent, the uptakes 21 are connected to horizontal flue passages 22 which in turn are connected to a collector chamber constructed as horizontalflue galleries 23. In this embodiment, the horizontal passages 22 and flue galleries 23 are centrally located in the boiler above the firebox 12.

For transferring heat to the water circulating through the header 16 and the water passages 17 in the sections of the boiler, the flue gases produced in the firebox by natural or forced draft firing are forced laterally toward the outer wall of the boiler to pass upwardly between the adjacent boiler section through the vertical uptake passages 21. As may be seen by reference to FIG. 1, these uptake passages 21 open in their lower part to the upper region of the firebox crown 24. The vertical limits of the uptake passages 21 are defined by the rounded upper corners of the boiler itself, which form turn-around passages 21. These passages 21 are disposed laterally of the horizontal flue passages 22 with which they communicate by means of downwardly directed connecting passages 21" so that the hot flue gases pass from the firebox to the horizontal passages 22 via the vertical uptakes 21, the turn-around passages 21' and the downwardly directed passages 21". Since a vertical uptake is formed at each side and between adjacent sections of the boiler, the hot flue gases in the firebox are divided into a plurality of individual streams of gases equal in number to the number of uptakes and these streams of gases flow into the horizontal passages 22.

In accordance with a principal feature of the present invention, means are provided for controlling the flow of flue gases in the uptake passages 21 so that a uniform distribution of the flue gas along the length of the boiler is obtained and for controlling the flow of flue gases in the horizontal passages 22 and flue galleries 23 so that two separate paths of flue gas flow are provided. More specifically, means are provided for insuring that all boiler sections contribute equally in the transfer of heat to the heating surfaces by controlling the flow of flue gases in a pattern such as to provide for optimum heat transfer.

For this purpose, the vertical smoke collar or flue gas outlet 13 is secured to the top of the boiler substantially at or near .the center thereof for receiving flue gases from the flue galleries 23 (collector chamber) and directing the gases to a chimney. As may be seen, the vertical outlet 13 is in communication with the flue galleries through vertical outlet passages 25 formed at the center of the centrally located intermediate boiler sections above the flue galleries.

In keeping with the present invention, turn-around passages 26 are provided at the front and rear of the boiler for connecting the horizontal passages 22 to the horizontal flue galleries 23. As a result, flue gas flowing in the uptakes 21 will be dispersed into the horizontal passages 22 wherein it will flow along two separate paths, indicated by arrows 27a and 27b, to opposite ends of the boiler, around the turn-around passages 26, and along the flue galleries 23 to the vertical output passages 25 which cooperate with the vertical outlet 13. Due to the fact that two separate paths of flue gas flow are provided, it follows that the cross-sectional area of the flue gas passages may be reduced to substantially one-half the cross-sectional area for boiler sections wherein only a single path of flue gas flow is provided, i.e., wherein the outlet is connected to the flue galleries at the rear of the boiler, without reducing the boiler capacity for the same total flue gas volume. Additionally, assuming the same cross-sectional area for the flue gas passages, the same firebox and the same pressure loss or forced draft loss through the boiler, it follows that the total flue gas volume may be doubled resulting in the boiler capacity being substantially doubled as compared to boilers having only a single path for flue gas flow. Further, the amount of flue gas flowing along the two paths is substantially equal so that uniform distribution of flue gas flow automatically results, i.e., substantially equal amounts of flue gas flow through the various uptake passages 21 throughout the entire length of the boiler.

While the boiler sections shown in FIGS. 1-4 have laterally disposed vertical uptakes 21 adjacent theside walls of the boiler for receiving shares of the flue gas produced in the firebox, various other vertical uptake arrangements have been found suitable. One such alternative uptake arrangement is shown in FIG. 5 wherein laterally disposed vertical uptakes 21 extend vertically above the firebox 12 and the horizontal passages 22 and galleries 23 are laterally disposed outwardly from the uptakes, the horizontal galleries 23 being disposed adjacent the side walls of the boiler. It will be seen that the uptakes 21 located generally in the central region are connected through turnaround passages 21 and downwardly directed passages 21" to the horizontal passages 22. Additionally, it follows that the horizontal passages 22 are connected to the flue gas galleries 23 through turn-around passages at opposite ends of the boiler (see FIG. 1). In operation, gaseous combustion products pass up through the vertical uptakes 21, around the turn-around passages 21', down the passages 21" and into the horizontal passages 22. Once in the horizontal passages 22, the gases pass along two separate paths toward opposite ends of the boiler, around the turn-around passages at opposite ends of the boiler into the horizontal flue galleries 23, and along the flue galleries 23 to the center of the boiler wherein they join in vertical outlet passages 25, provided in the intermediate boiler sections, to which a vertical outlet is secured.

Front and rear sections of the arrangement shown in FIG. 5 have not been illustrated. However, it will be apparent to those skilled in the art that such sections will be provided with gas flow passages corresponding to the passages of the front section illustrated in FIG. 5.

In further keeping with the present invention, adjacent sections of the boiler are positively and permanently sealed gastight. More specifically, the boiler sections are sealed therebetween such that the interior of the boiler may be maintained under positive pressure, as with forced draft firing, without leakage of gas from the boiler interior into the surrounding space. Such scaling is also important for natural draft firing since uncontrolled air leakage into the boiler, which might impair uniform flue gas distribution, is eliminated throughout the life of the boiler so as to assure high efficiency of operation. In carrying out this aspect of the invention, the boiler sections are cast with sealing lands 30 provided around the outer edge thereof so as to form a substantially continuous loop around the firebox (see FIGS. 2-5). Preferably, the sealing lands extend around the periphery of the upper portion of each section and extend laterally along the portion of each section which defines the lower surface of the firebox. With such an arrangement, it will be apparent that the sealing lands are accessible even after the boiler has been assembled. Additionally, these sections are cast with sealing lands 31 centrally formed about the horizontal passages 22 and flue galleries 23 thereby separating the various regions of the boiler from one another. When two of the boiler sections are moved into abutting relationship, the sealing lands thereon will be moved into register so that a seal is provided which extends in a continuous loop around the firebox and gas passages of the boiler.

So as to provide an air and gastight seal between registering lands on adjacent sections of the boiler and thus for the purpose of effectively sealing between every section of the boiler, the sealing lands are grooved or channeled for receiving sealing material herein shown as heat resistant flexible rope 35, such as asbestos rope or the like. A continuous length of rope is laid in the grooves or channels 36 formed in the sealing lands 30 so that the ends thereof overlap and a continuous seal is provided around the entire boiler interior. Similarly, a length of rope is laid in the groove 37 of the lands 31. It is preferred that the asbestos rope should be glued in place in the curved sealing grooves, using adhesive (see FIG. 6). As will be readily appreciated, this also facilitates erection of the boiler because the asbestos rope is held in place. To insure that the sealing material remains intact upon dismantling of the boiler, the adhesive should be applied only to one side of the asbestos rope in the grooved lands of one section of the boiler.

In the erection of the boiler shown as exemplary in the drawings, a slip nipple 19 is installed in the upper slip nipple opening 18 of one section, for example, the front section illustrated in FIG. 2, to form the internal header 16. Smaller, lower nipple openings 40 are then conditioned for receipt of lower nipples 41 which are pounded in place to form a part of the water passage system of the boiler. After the asbestos rope has been placed on the one section, for example, a front section as illustrated in FIG. 2, the upper and lower nipple openings of a second section, for example, an intermediate section as illustrated in FIG. 3, are then pre pared for receiving the nipples. The intermediate section is then driven against the front section with a heavy mallet or the like to start the nipples into the lower openings and into the upper ports or openings of that section. At this point, draw rods 45 are assembled on the sides of the boiler and the intermediate section is then connected by means of these draw rods to the front section. The remaining sections, i.e., intermediate and rear sections, are then assembled in place following the same sequence of steps.

For insuring a perfect seal between boiler sections, it is desirable that the grooved or channeled sealing lands constructed in the outer wall of the boiler be fash ioned so that, during the operation of drawing the adjacent sections of the boiler together by means of the draw rods, the asbestos rope in the outer curved sealing groove will be compressed so as to form a relatively denser flue gas impervious bead toward the inside of the boiler. For this purpose, the meeting lands 30 are so formed that when the boiler sections are drawn fully together, to the position shown in FIG. 6, the gap 50 separating the

inside edges

51 and 52 of the boiler sections is smaller than the gap 53 separating the outer edges 54 and 55. The draw rods 45, when drawing the adjacent boiler sections together, act to compress the asbestos rope 35 and actually extrude it into the gaps 50 and 53 separating the sections. By providing a larger space toward the outside edge of the outer wall of the sections, however, the compressed asbestos rope is allowed to escape somewhat, providing compression relief, while the portion of the asbestos rope toward the inside of the boiler is made denser and gas impervious.

In view of the foregoing, it will be seen that the invention provides a sectional boiler construction with sealing means between sections fully enclosing the boiler interior, which, due to such sealing, can be operated with either forced draft or natural draft firing and in which under either mode of operation the gaseous products of combustion are uniformly distributed throughout the entire length of the boiler and are dispersed along two separate paths. As a result, the cross-sectional areas of connecting horizontal passages may be reduced allowing for more eificient heat transfer so that, with the same total flue gas volume, the boiler has substantially the same capacity. Moreover, the cross-sectional areas may be maintained the same so that the total volume of flue gas may be doubled resulting in the boiler capacity being substantially doubled.

I claim as my invention:

1. In a multiple pass boiler adapted to be erected so as to define a sealed firebox, the combination which comprises, fully enclosed uptakes disposed laterally and extending from the firebox vertically adjacent the side walls of the boiler for receiving shares of the flue gas produced in the firebox, the uptakes being regular in cross section and extending uninterruptedly from the firebox to the top of the boiler, horizontal passages disposed centrally above said firebox inwardly from the uptakes, means connecting said horizontal passages to said uptakes, vertical outlet passages provided centrally at the top of the boiler above the firebox for receiving flue gas from the horizontal passages and uptakes, a vertical outlet mounted centrally at the top of the boiler and connected to the outlet passages, and means including turn-around passages for connecting the horizontal passages to the outlet passages so that the flue gas flow is divided into two paths causing substantially equal shares of flue gas to flow through the uptakes.

2. In a multiple pass boiler adapted to be erected so as to define a sealed firebox, the combination which comprises, fully enclosed uptakes extending from the firebox vertically for receiving shares of flue gas produced in the firebox, the uptakes being regular in cross section and extending uninterruptedly from the firebox to the top of the boiler, a horizontal collector chamber disposed adjacent the side walls of the boiler and extending the length of the boiler for receiving the streams of flue gas from the uptakes, a vertical flue gas outlet mounted centrally at the top of the boiler, vertical passages for connecting the collector chamber to the outlet, means including horizontal passages laterally disposed outwardly from the uptakes and turn-around passages at opposite ends of the boiler for connecting the uptakes to the collector chamber so that substantially equal shares of flue gas flow through the uptakes and the flue gas flows to the collector chamber.

3. In a boiler adapted to be erected so as to define a sealed firebox, the combination which comprises, fully enclosed uptakes extending from the firebox vertically for receiving shares of flue gas produced in the firebox, the uptakes being regular in cross section and extending uninterruptedly from .the firebox to the top of the boiler, a vertical flue gas outlet mounted centrally at the top of the boiler, a horizontal passage extending the length of the boiler, turn-around passages for connecting the uptakes to the horizontal passage so that flue gas from the uptakes flows into the horizontal passage, a horizontal collector chamber extending the length of the boiler, turnaround passages at opposite ends of the boiler for connecting the collector chamber to the horizontal passage so that flue gas from the horizontal passage flows into the collector chamber and so that substantially equal shares of flue gas flow through the uptakes, and vertical passages provided centrally at the top of the boiler for connecting the collector chamber to the outlet.

4. A boiler as defined in claim 3 including a plurality of boiler sections, sealing means provided in facing surfaces of adjacent boiler sections which register and are formed in continuous loops around the boiler sections so that the interior of the boiler is positively sealed from the surrounding atmosphere, and sealing means provided in facing surfaces of adjacent boiler sections which register and are formed to seal off the forward outlets from the firebox and the uptakes.

5. A boiler as defined in claim 3 wherein said firebox, horizontal passages, collector chamber and vertical passages are surrounded by water passages.

References Cited by the Examiner UNITED STATES PATENTS 739,503 9/1903 Murphy 122225 X 1,164,061 12/1915 Bechfield 122225 X 1,240,517 9/1917 Van Leeuwen et al. 122-225 1,851,453 3/ 1932 Silver 122-225 2,3 16,603 4/ 1943 Livar 122225 KENNETH W. SPRAGUE, Primary Examiner.

Claims

1. IN A MULTIPLE PASS BOILER ADAPTED TO BE ERECTED SO AS TO DEFINE A SEALED FIREBOX, THE COMBINATION WHICH COMPRISES, FULLY ENCLOSED UPTAKES DISPOSED LATERALLY AND EXTENDING FROM THE FIREBOX VERTICALLY ADJACENT THE SIDE WALLS OF THE BOILER RECEIVING SHARES OF THE FLUE GAS PRODUCED IN THE FIREBOX, THE UPTAKES BEING REGULAR IN CROSS SECTION AND EXTENDING UNINTERRUPTEDLY FROM THE FIREBOX TO THE TOP OF THE BOILER, HORIZONTAL PASSAGES DISPOSED CENTRALLY ABOVE SAID FIREBOX INWARDLY FROM THE UPTAKES, MEANS CONNECTING SAID HORIZONTAL PASSAGES TO SAID UPTAKES, VERTICAL OUTLET PASSAGES PROVIDED CENTRALLY AT THE TOP OF THE BOILER ABOVE THE FIREBOX FOR RECEIVING FLUE GAS FROM THE HORIZONTAL PASSAGES AND UPTAKES, A VERTICAL OUTLET MOUNTED CENTRALLY AT THE TOP OF THE BOILER AND CONNECTED TO THE OUTLET PASSAGES, AND MEANS INCLUDING TURN-AROUND PASSAGES FOR CONNECTING THE HORIZONTAL PASSAGES TO THE OUTLET PAS-