US2334968A - Boiler construction - Google Patents

Description

Nov- 23, 19 J. w. THROCKMORTON EI'AL 2,334,958

BOILER CONSTRUCTION Filed Nov. 11, 1942 2 Sheets-Sheet 2 1" "WWW I I I v INVENTORS. Jo/m lMTh/"oakmarfon v John .5 14 0/03 BOILER OONBTBUCTIQN John W.

poration of Delaware Application November 11, 1942, Serial No. 465,240

2 Claims.

This invention relates to improvements in boiler construction, and refers more particularly to a boiler assembly mounted in a vertical furnace, the assembly comprising a transverse reservoir positioned in the upper portion of the furnace, a circular manifold below the furnace, vertical heat exchange tubes arranged adjacent fthe'inside wall of the furnace connecting the lower manifold with the upper reservoir, and downcomer pipes from the reservoir to the manifold.

through which the fluid medium is caused to more rapidly circulate due to the rapidity of heating the heat exchange elements and the difference in temperature between the fluid in the heat exchange elements and that outside of the heat exchange elements in the reservoir and downcomer pipes.

The construction provides a design in which the heating surface, including the upper reservoir or drum and lower circular manifold, as well as the intermediate connecting tubes, may be shop assembled as a single unit and hydrostatically tested before shipment.

One object is to provide a high rate of radiant heating surface to the convection heating surface employing extended surface in the convection zone and directing the combustion gases through the furnace to obtain uniform distribution of heat and heat absorption throughout.

Another object of the invention is to provide a boiler and furnace construction of low weight, compact, completely weather-proof so that it may be installed in the open without the necessity of a conventional boiler house or other enclosing structure, and one which may be easily and inexpensively cleaned and repaired.

Other objects of our invention will appear from the following description.

Inthe drawings, forming a part of this speciflcation, and wherein like numerals are employed to designate like parts throughout the same,

Fig. l is a sectional side view of the furnace with a portion of the central section broken away.

Fig. 2 is a view taken along the line 2-2, Fig. 1, in the direction of the arrows.

Fig. 3 is a view taken along the line 3-3, Fig. 1, in the direction of the arrows.

Fig. 4 is a fragmentary side elevation of the lower manifold.

Throckmorton. Wilton, and John s. allis, Darien. Conn. alligno Development Company, New York. N.

to retro-Chem Y.. a cor- Fig. 5 is a view taken along the line 5-8, Fig. 4, in the direction of the arrows.

Referring to the drawings, the furnace proper comprises a cylindrical shell portion l0 supported upon standards H, and tapered at the top at Ma to a flue or chimney i2.

The steel shell or casing of the furnace is lined with a layer of insulation shown at l3, and a layer of refractory material H. In the lower part of the furnace are directional burners l5, which may be adjusted in any manner to direct the combustion gases so that the heat is uniformly' distributed inside the furnace chamber.

Although but two burners are shown, it is understood that any number may be used to supply the necessary amount of heat. Fuel is supplied to the burners throu'gh pipes II. It is contemplated also that in place of oil or gas burners, the furnace may be fired-by coal, or any other suitable fuel.

Transversely across the upper portion of the furnace is supported a cylindrical reservoir i'l. This reservoir is equipped with a liquid level gauge l8, a cleanout plate 19, fluid inlet pipe 20, and a vapor discharge pipe 21.

Below the combustion chamber of the furnace is positioned a circular manifold 22, which is preferably located just outside the combustion chamber. This manifold is positioned in an enclosed annular space to prevent loss of heat by radiation.

Connected into the ends of the upper reservoir and at locations apart on the lower manifold are two downcomer pipes 23, connected at the top by flanged nipples to the reservoir, and at the bottom by U-ben'd connections 24 which have flanged connections to the downcomer pipe and toshort pipe connections from the manifold.

Although external down-pipes are shown, it is quite feasible to employ one or more of the lowest tubes on each side of the drum or reservoir I1 as downcomers, and when so used they should .be increased in diameter and the extended surface flns removed. This would give down-pipe capacity within the furnace proper, through larger sized tubes having considerably less heat absorption than there would be in the steam generating surface, so that a proper thermal circulation would be maintained. Such arrangement, while probably not as eflicient as the external down-pipes, would function satisfactorily and is generally in accordance with conventional practice.

within the furnace and depending from the upper portion of the combustion space is a conical baiiie 25, whose base has a cylindrical extension 25a which has the same diameter as the base of the cone.

Adjacent the inside wall of the furnace, and receiving both radiant and convection heat from the combustion gases, are a plurality of heat exchange: tubes 26, connecting the upper reservoir ll withthe lower manifold 22. These tubes are.

welded or rolled into the top of the manifold, as shown in Fig. 4, and into the bottom portion of the reservoir, as best indicated in Fig. 3.

On the exterior surface of the heat exchange tubes, in the annular space between the upper portion of the baflie 25 and the furnace wall, is an extended surface in the form of fins which serve to increase the heat exchange characteristic and ability of the tubes in this section of the furnace to conduct heat from the combustion gases to the fluid passing through the tubes.

' 23. As the'heating continues a very rapid circulation of water and steam will flow upwardly through the heating tubes 26 and downwardly from the reservoir through downcomer pipes 23. Steam vaporized in the system passes of! through the discharge pipe 2|, and additional make-up water is introduced to the system.

Basically, as suggested, the rate of thermal circulation depends upon the difference in the weights of the fluid columns in the down-pipes and in the heated section. By employing vertical tubes both in the down-pipes and heated section, and positioning the down-pipes outside the heated zone, no heat is absorbed by the fluid in the down-pipe section and a higher rate of thermal circulation will be obtained.

Another factor involved in the rate of circulation is friction loss occasioned by the fluid contact with the inside surfaces of the tubes. This loss is greatest where maximum vaporization occurs. By using extended surface fins on the tubes in the upper part of the heater where maximum vaporization takes place, friction is reduced and a higher rate of circulation results.

As in the usual practice in boiler construction, there is located in the vapor space of reservoir ll a mist extractor 21.

As suggested heretofore, the heating surface may be assembled and hydrostaticaliy tested :in the shop where manufactured. The furnace casing or shell may likewise be constructed as a single unit and lined at the time of installation with suitable refractory. By making the diameter of the lower manifold or mud ring 22 smaller than the lining of the furnace, the entire boiler unit may be inserted through the top of the casing and the external down-pipes installed and connected after the boiler unit is in place. In case of repairs or replacement of tubes by discomne'cting the down-pipes the entire unit can be removed from the furnace setting.

It is contemplated'that the radiant tube length will be considerably longer than the convection tube length. The centrally positioned heat source serves to distribute heat uniformly over the radilower or' radiant tubes of the bank absorb heat at a very high rate, whereas the majority of the assaccs tubes, which are subjected to convection heat, absorb heat at a relatively low rate.

,It is also contemplated to connect the steam vapor line 2| to two or more vertical tubes which are included in the circular bank but are not above the top reservoir. The tubes of such a superheater may or may not be equipped with extended surface fins as desired.

To clean out the unit, access may be had to the upper reservoir through manhole plate II. From inside the reservoir the heating tubes may be turbined or otherwise cleaned, the dirt and accumulation from the tubes removed from the bottggn manifold or mud ring 22 through cleanout A permanent blow-down connection, not shown, may be connected into the lower manifold at any convenient location if desired.

As an example of the compactness of design, a one hundred thirty-five (135) horsepower boiler unit has a furnace diameter of approximately seven (7) feet, a tube circle diameter of flve (5) feet, three (3) inches, and eighteen (18) feet effective tube length in the heating zone, thirteen (13) feet of which is in the radiant section, and

flve (5) feet of fln tube convection section with a forty-two (42) inch diameter top reservoir or drum.

From the foregoing it will be seen that our invention is well adapted to attain all of the ends and objects hereinbefore set forth, together with other advantages which are obvious and which are inherent to the structure of the device.

Having thus described our invention, we claim:

1. A boiler construction comprising avertical chamber, a source of combustion gases in the lower portion of the chamber, a flue at the top,

a baflle positioned intermediate the flue and comcylindrical reservoir transversely positioned in the upper portion of the chamber, a circular manifold below the chamber, heat exchange elements surrounding the chamber and adjacent its inside wall surfaces connecting the manifold and reservoir, downcomer elements outside the chamber connecting the reservoir and manifold. a fluid inlet to the reservoir, a vapor outlet therefrom, and extended surfaces on the heat exchange elements in that portion of the chamber wherein the path of the combustion gas is outwardly diverged by the baths.

2. A boiler construction comprising a vertical cylindrical chamber, a source of combustion gases in the lower portion of the chamber, a flue at the top, a reservoir in the upper portion of the chamber, a lower manifold below the chamber, tubuv lar heat exchange elements arranged in a circle surrounding the chamber'and adjacent its inside wall surfaces connecting the manifold and reser-

Images