US2867415A - Vapor heater - Google Patents

Description

5 w w. SCHROEDTER 2,867,415

VAPOR HEATER Filed June 17, 1955 '2 Sheets-Sheet 1 Willburt W. Schroedter Fig. I.

ATTOR NE 1" 2,867,415 VAPoR HEATER Willburt W; Schroedter, New York, N. Y., assignor to Combustion Engineering, Inc., New York, N. Y., a

corporation of Delaware Application June 17, 1955, Serial No. 516,261.

1 Claim. (Cl. 257-241) This invention relates to vapor heaters of the tubular panel type and has particular relation to such heatersemployed with vapor generators that have furnaces into which fuel is introduced and burned with the combustion gases thus generated traversing the vapor heater and with the vapor heater being located so as to receive luminous radiation from the'burning fuel within this furnace.

In accordance with this invention there is provided a vapor heater comprised of a number of tubular panels positioned within a gas pass leading from the furnace of a vapor generator. These panels are spaced across the width of the gas pass and have their median planes in parallel relation with the gas flow with the panels being located so that their upstream edge is subjected to radiant heat from the furnace. Each of the panels is preferably atent made up' of a plurality of tubes positioned next to one another and formed into a panel by being sinuously bent and internested one Within the other. The tubes of the several panels of'the vapor heater are interconnected so that the vapor flows serially through these panels in passing through the vapor heater. In order to prevent the tubes that are nearest to the upstream edge of the panels from being overheated the panels are interconnected in such a manner that thesame steam does not flow through the tubes nearest the upstream edgeof eachof the panels but instead the steam that flows through the tubes adjacent the upstream edge of one panel is directed through tubes that are more remote from the upstream edge of another panel.

It is an object of this invention to provide an improved vapor heater of the tubular panel type. 1

'Other and further objects of the invention will become apparent to those skilled in the art as the description proceeds.

With the aforementioned objects in view, the invention comprises an arrangement, construction and combination of the elements of the inventive organization in such a manner as to attain the results desired as hereinafter more particularly set forth in the following detailed description of an illustrative embodiment, said embodiment being shown by the accompanying drawing wherein:

Fig. 1 is a vertical sectional view showing a portion of the furnace of a vapor generator and a vapor heater constructed in accordance with the present invention associated with this furnace.

Fig. 2 is a transverse sectional view taken along line 2-2 of Fig. 1 and showing the panels of the vapor heater interconnected and spaced across the gas pass leading from the furnace.

Fig. 3 is a vertical sectional View taken along line '33 of Fig. 1 and likewise shows the tubular panels spaced ?atented Jan. .6, 1959 sented tube sections being taken along line 55 of Figs. 1 and 3.

Referring now to the drawing, wherein likereference characters are used throughout to designate like elements there is shown a furnace 10 which has its Walls lined with steam or vapor generating'tubes 12 in the conventional manner and which is fired with a suitable fuel through burners 14 which may be located at the corners'of the furnace and be of the well known vertically tiltable type. This fuel is burned within furnace 10 with the combustion gases that are generated passing upwardly fro-m the furnace into the gas pass 16 that extends upwardly from the furnace and may be said to form an extension of the furnace with the gases leaving gas'pass 16 through duct or passage 18.

Extending downwardly into gas pass 15 is the steam or vapor heater 20 which may take the form of a superheater or reheater for reheating the steam or vapor generated in tubes 14 or may be any other type of vapor heater. This vapor heater 20 is composed of tubular panels 22, 24, 26 and 28 that are position-ed in side-byside spaced relation across the width of the gas pass with each panel being of such size that it extends almost the entire distance across the depth of gas pass 16.

In the illustrative organization shown each of the panels of the vapor heater 20 is made up of six tubes that have been'designated 30, 32, 34, 36, 38 and at as indicated, with the axes of each of these tubes lying in the median plane of the panel and with the tubes being sinuously bent and internested as shown.

The vapor to be heated enters the tubes of panel 22 from inlet header 42, which is connected to the initial run or leg of the sinuously formed tubes of this panel, and is conveyed serially through panels 22, 24, 26 and 28, respectively, leaving panel 28 through the final run or leg of the tubes of this panel and entering outlet header 44 to which these tubes are connected. In order for the steam to serially flow through these several panels the tubes of adjacent panels are interconnected by means of combustion gases flowing upward through gas pass 16 give up heat to the panels of vapor heater 2% by means of convection heat exchange as well as non-luminous radiant heat exchange. In addition the panels also re, ceive luminous radiant heat from the burning mass of fuel within furnace 10 with this heat being extremely intense and with the intensity of this heat received by the tubes in each panel decreasing with the distance of the tubes from the upstream edge of the particular panel, i. e., the further the tube is displaced from the leading edge of the panel the less of this luminous radiant heat it receives. The intensity of this luminous radiant heat is such that of the total heat absorbed by all of the tubes in each panel-that absorbed by the upstream tube, i. e., the tube extending along the upstream edge of the panel, will be much greater than that absorbed by any other tube and with the percentage of heat absorbed by each tube decreasing as its distance from the upstream edge of the panel increases. This Will become evident by a consideration of Fig. 5 which is a graphic representation of the total heat absorbed by the vapor in passing through panel 22 with the shaded area under curve 48 representing the total heat absorbed and with the portionof the shaded area to the right of each represented tube indicating the portion of this total that is absorbed by the vapor in the respective tube. It is thus evident that the vapor in the tubes nearest the upstream edge of the panel (tube 30 being disposed along the upstream edge) absorbs considerably more heat than those remote from the upstream edge resulting in a substantially higher tube metal temperature in the tubes nearest this upstream edge.

It will thus be readily apparent that if tubes 30 through 40 of one panel were connected to the coresponding tubes 30 through 40 of the next succeeding panel the stream that flows through the tube extending along the upstream edge of one panel would also flow through the tube extending along the upstream edge of the succeeding panel, and likewise the steam flowing through the second tube from the upstream edge of one panel would flow through the corresponding tube of the next succeeding panel and so on. This would cause the tubes near the upstream edge of panels near the end of the vapor heater, i. e., the exit end relative to vapor flow, to either become prohibitively hot or if not prohibitively hot would result in the necessitating of fabricating these tubes of extremely expensive heat resisting metal to Withstand the high temperature that would be encountered. 1

In order to avoid overheating the tubes near the upstream edge of the panels and to more nearly attain a uni-' form metal temperature of the tubes in the panels the tubes in different panels are interconnected in a manner so that the vapor that passes through the tubes of the upstream edge of one panel will pass through tubes more remote from the upstream edge of other panels of the vapor heater with this being accomplished in the illustra-- tive organization by connecting tubes 30, 32, 34 of one panel with tubes 36, 38, 40 of the next succeeding panel through connecting conduits 46. Thus the vapor that flows through tubes 30, 32 and 34 of one panel, which are the tubes nearest the upstream edge of each of the panels; is directed through tubes 36, 38 and 40, respectively, of the nearest succeeding panel with these latter tubes being more remote from the upstream edge of the panel thereby attaining a more equal distribution of the heat absorbed by the steam in the tubes and accordingly of the tube metal temperatures.

It is to be understood, however, that while this inter- 1 connection of the tubes of different panels will accomplish applicants purpose of providing more uniform metal temperature of the tubes in the panels other and different interconnecting arrangements may be employed for accomplishing this purpose with the essential requirement being that the pattern of steam flow paths in the panels making up the vapor heater be varied'sufliciently so that the same steam does not flow through the tubes that are nearest the upstream edge of each of the panels. t

It will be evident that with the novel vapor heater of the present invention the vapor in flowing from inlet header 42 to outlet header 44 traverses gas pass 16 both across its depth as well as across its Width so that any variation in gas flow or gas temperature in any direction across the gas pass will be averaged out so as to have no substantial effect upon the vapor temperature and at the same time the tubes nearest to the upstream edge of the of the several panels are protected from becoming overheated or extremely hot in comparison with the other'tubes in the panels.

While I have illustrated and described a preferred embodiment of my novel organization it is to be understood that such is merely illustrative and not restrictive and that variations and modifications may be made therein without departing from the spirit and scope of the invention. I therefore do not wish to be limited to the precise details set forth but desire to avail myself of 'such changes as fall within the purview of my invention.

What I claim is: i

A vapor heater comprising a pluralityof vertical panels disposed in side-by-side relation within a gas passageway opening directly out of a furnace and through which combustion gases from said furnace are directed, the median planes of the panels being inspaced relation across the width of the passageway and generally parallel with the gas How, the panels being disposed so that the upstream edge thereof is subjected to intense radiant heat with the portions of the panels more remote from this upstream edge receiving progressively less radiant heat, said panels being comprised of numerous continuous tubes interconnected between inlet and outlet headers. with a portion of each of the tubes being disposed within the plane of each panel and thereby making up a portion ofthe panel whereby the vapor flows serially through the several .panels, these tube portions being sinuously bent and internested to form the panels, in passing from one panel to another the group of tubes disposed nearest the upstream edge of a panel and comprising generally half of the tubes that make up the panel being crossed with relation to the remainder of tubes with each of these groups of tubes being crossedin a body so that the relative location of the tubes within each group remains unchanged while the relative location of the groups is charged with this crossing of tubes in this manner positioning alternate of these groups of tubes nearest'the upstream edge in adjacent panels.

References Cited in the file of this patent

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