US3067729A - Simple boiler installation - Google Patents

Description

Dec. 11, 1962 A. HUET 3,067,729

SIMPLE BOILER INSTALLATION Filed Aug. 1, 1957 2 Sheets-Sheet 1 Q TA INVENTOR ANDRE HUET NEY Dec. 11, 1962 A. HUET SIMPLE BOILER INSTALLATION 2 Sheets-Sheet 2 Filed Aug. 1, 1957 INVENTOR ANDRE HUET B W m ATTORNEY United States Patent 01 3,067,729 SllVIPLE BOILER INSTALLATION Andre Huet, 48 du President Wilson, Paris 16, France Filed Aug. 1, 1957, Ser. No. 675,770 Claims priority, application France Aug. 14, 1956 10 Claims. (Cl. 122-333) The present invention relates to steam generating and superheating apparatus and particularly to a boiler of simple and compact construction and of high heat transfer efficiency.

The invention contemplates a boiler having a cylindrical casing of circular, polygonal or other shape, through which a hot fluid flows for heat transfer and its characteristic consists in that the diflerent elements constituting the boiler proper, i.e. the water tube assembly, the economizer, etc., located inside the casing, are conceived so as to present a symmetry axis which coincides with the axis of the cylindrical casing. All these elements are disposed in a manner as to show a radiating arrangement around the symmetry axis so that each can be separated into sectors of identical construction. Consequently, the manufacture of these sectors can be carried out in series at the plant. like pre-fabricated parts, and the erection of the complete boiler at site requires only a minimum of welding. On the other hand, the symmetric and radiating construction of the different elements at the inside of the casing insures a minimum of pressure loss in the stream of the heating fluid flowing through the casing and over the said elements, which elements are furthermore conceived in such manner that the water and the steam which form therein are likewise subject only to a minimum of pressure loss in the course of their circulation in the apparatus.

Further characteristics of the boiler forming the object of the invention will appear in the course of the following description referring to the attached drawings in which:

FIGURE 1 is a schematic partly sectional elevation of a boiler embodying the invention.

FIGURE 2 is a schematic cross section on line 2-2 of FIGURE 1, showing the upper part of the boiler proper.

FIGURE 3 is a perspective view on a larger scale showing the connection of a tube to a sub-header.

FIGURE 4 shows in vertical cross section the connection of the sub-header to one of the main headers.

FIGURE 5 shows on an enlarged scale and in transverse cross section a number of the water tubes with intermediate nuclear core elements between the water tubes.

As shown in FIGURE 1, the boiler assembly is arranged in a duct or casing of cylindrical form having a wall thickness suflicient to resist the pressure of the hot fluid from which heat is absorbed in the boiler elements. The shape of casing 10 can be circular, oval or even polygonal. In the example shown, its shape is circular. The axis is vertical and the hot fluid coming, for example, from a nuclear reactor circulates from the bottom to the top in the direction of arrow A.

The boiler assembly consists of groups of water tubes and the accessory apparatus, economizer and superheater, which are suspended by any suitable means inside casing 10. Viewing the structure of FIGURE 1 from top to bottom, an economizer 12 is followed by an assembly of water tubes 14 of a first, low pressure boiler, schematically shown in FIGURE 1 by two diagonal lines. Next is an assembly of water tubes of a high pressure boiler 16 and finally superheater 18, also shown schematically. The low pressure boiler 14 is of the same construction as the high pressure boiler 16, and only the latter one has been shown in more detail in FIGURE 1. Deflector plates 17 provided on the inside circumference of the casing direct fluid A towards the elements over which it has to flow.

3,067,729 Patented Dec. 11, 1962 ice According to the principles of the invention, economizer 12 as well as the two boilers 14 and 16 are built in such coincides with the longitudinal axis of casing 10, and the different tubes of these elements are parallel to the symmetry axis and are arranged in such manner that they are located in rows or groups that radiate around the axis. It is then possible to prefabricate these elements in advance at the plant in whole sectors which then can be assembled at site wtih a minimum of Welding required to complete the erection of the boiler.

Because of the similar constructions embodied in the economizer 12 and low pressure boiler 14 the detailed description begins here with the assembly of the water tubes forming the high pressure boiler 16. At the upper part and on the axis of symmetry a main vertically disposed feeding tank or drum 20 is located, forming a separator and Water and steam drum. The drum 20 is connected by tubes 22 to eight vertical headers 24 arranged as a ring around drum 20, as can be seen in FIGURE 2. These headers 24 are joined together by loop connections 26. In FIGURE 2 there are joined to each of the headers 24 nine transverse sub-headers 30 spreading out in fan shape along the radii of cylindrical casing 10 as shown in FIG- URE 2. In order to avoid havingthe nine sub-headers 30 leading from each header 24 forming a transverse screen, which would more or less close oflf the interior of casing 10, these sub-headers 30 have their ends connected into the related header 24 at different levels, for instance along an undulated line such as is shown in FIGURE 4. In this manner a staggering between the levels of the subheaders is attained which facilitates the passage of fluid A at this point.

To the radially extending bodies of the sub-headers 30, water and steam tubes 32 are in their turn connected, these being arranged parallel to the axis of symmetry of casing 10 and parallel with the direction of the flow of the hot fluid A; a descripton of these tubes will be given later. At their lower ends the tubes 32 are similarly connected to sub-headers 34 the number of which correspond to that of sub-headers '30; these are connected to a ring of vertical headers 36 joined through tubes 31 to a lower drum 38. It will be noted that in order to facilitate the flow of water and steam in the system thus constituted, he lower sub-headers 34 which distribute the water and the upper headers 30 which collect the water and steam mixture are inversely inclined with respect to the horizontal. Headers 24 and headers 34 are joined together in pairs by vertical water return pipes 33 and these are enclosed by a protective shield plate 35 which shelters them from the current of hot fluid A. Sub-headers 24 and 34 could also terminate directly in central drums 20 and 38 which would then have to have a larger diameter. Sub-headers 30 and 34 could also take on the shape of a crescent by drawing closer to the central drums.

Economizer 12 is constituted in a similar manner and comprises an upper drum or header 40 to which the fanned out sub-headers 42 are connected, while, at the lower part a header 44 collects hot water which is collected by radially disposed sub-headers 46. The arrangement of water tubes 32 of the economizer is perceptibly the same as that of the tubes of boiler 16.

The water or steam and water tubes 32 are preferably constituted by fin tubes having for instance eight fins, 50, as shown in FIGURE 3. At the inside of these finned tubes 32 plain walled tubes 52 can be provided forming passages through which the hot fluid following arrow A flows. The water and steam mixture circulates in the annular space 51 which separates the inside of finned tube 32 from the outside of the interior tube 52. In order to connect these annular spaces 51 with the sub-headers 30 and 34, the end of tube 32 is bevel edged, as can be seen in FIGURE 3, and the space between tubes 32 and 52 is sealed at the top by a plate 53 or by any other similar means, to which a discharge duct 55 is welded, the latter being connected to a sub-header 3% (or 34) as shown in FIGURE 3. The bevel edge end of tube 32 favors the discharge (arrow C) of the water and steam mixture towards the top, i.e. towards the sub-header.

At the inside of the finned tube 32 or in the annulus 51 between this tube and the straight tube 52, a spiral deflector 56 is arranged, the axis being parallel to the axis of the tube. The spiral deflector is arranged so as not to touch the inside walls of the annulus 51 as constituted by tube 52. The effect of this spiral deflector is to give the water and steam mixture a gyratory movement and the centrifugal force has the effect that the water flows towards the outside of the spiral and falls back towards the bottom, while the steam rises along the inside wall of the annulus in the space between the free edge of deflector 55 and the inner wall of tube 52.

Likewise, it is possible to arrange in the water and steam sub-header 3t) inclined deflectors, which have the effect to have the steam flow towards the top, while the water withheld flows under the eflect of gravity again towards the bottom. In a general manner, therefore, the system of water and steam separation is located in the tubes and sub-headers of the boiler instead of being arranged in a drum at the outlet of the boiler as is generally the case. This arrangement is advantageous due to the fact that the length of the boiler tubes necessitates as quick as possible a separation of the steam formed and of the water.

The finned tubes 32 are distributed as shown schematically for one of the boiler sections, FIGURE 2 (upper part) in such manner as to suitably fill in the space offered by the whole section of casing outside the ring of headers 24 and shield 35. The dimensions of these finned tubes as well as the dimensions of inside tubes 52 varies according to the position of the tube and are selected so that the tubes operate approximately under the same conditions in regard to heat exchange, regardless of whether they are located at the periphery or closer to the central region. It is also possible to arrange the tubes in pairs and to connect them by means of Y-tube sections to the water and steam sub-headers 3t} and by varying the inclination of the level of the groups of two or more fin tubes in relation to the axis of the sub-headers, to insure an equal density of tubes over the whole section of casing 10. The tubes of larger diameter can be located at the periphery so as to take better advantage of the space available. It is also possible to vary the number of fins on the tubes, and the shape of deflector cores 6%) preferably arranged between the tubes.

In fact, as can be seen in FIGURE 5, it is possible to arrange among the tubes 32 deflector cores 60 constituted, for instance, by cross shaped bars, the branches of which are preferably un-dulated. In this manner the passages, open to the hot fluid A between the different fin tubes show variations in section and variations in direction which favor heat exchange. The dimensions of these deflector plates and the importance of the undulations on their branches can also vary depending on whether one goes from the center to the periphery in adjusting the distribution of fluid A over all fin tubes 52 to make them operate under the same conditions.

The boiler feed water arrives through a pipeline 62 at the upper par-t of economizer 42 and is fed in drum .0. This heated water is withdrawn from lower collector 44 through a pipe 64 arranged on the central axis of the boiler and terminating in the lower part of lower drum 38 of the boiler proper, as shown in FIGURE 1. The steam forming in tubes 32 of the boiler, collected in upper drum 20, is directed through pipe 66 (arrow D) towards superheater 18, from where it leaves through pipe 68.

The axis of the boiler, instead of being vertical as shown could be inclined. Furthermore, fluid shown passing in direction A, instead of flowing from the bottom to the top, could also flow from top to bottom. In this case the position of the economizer and superheater would be reversed, i.e. that the superheater would be located at the upper part of the arrangement and the economizer at the outlet of the hot fluid.

In casing 1d are shown two boilers proper, one at low pressure, the other at high pressure. It is possible that there could be therein only one, or that there could be therein three or more.

Besides the advantages and convenience of the construction which a boiler embodying the invention offers, it will be noted that its elements are designed in such manner as to decrease pressure losses. In fact, the hot fluid A gives up its heat by following a preceptible straight line and, consequently, with a minimum of pressure losses. On the other hand, the arrangement of the headers and sub-headers of the different heater components and their inclinations are such that the flow of the water and steam is produced in a direction favoring gravity.

What I claim is:

1. In a boiler; a cylindrical casing having at opposite ends thereof an inlet and an outlet for admission and discharge of a fluid from which heat is extracted; a water supply header and a steam and water collecting header mounted within the casing and located in spaced relation on its longitudinal axis; steam gene-rating tubes intermediate said headers disposed substantially in radial alinement and arranged in concentric rows about said axis with the tubes parallel thereto; a plurality of sub-headers radiating from said axis in pairs spaced axially of the casing and connecting with the upper and lower ends of radially alined tubes of said rows; a series of water distributing sub-headers disposed in a ring about said water supply header and a second series of steam and water collecting sub-headers disposed in a ring about said steam and water collecting header and each being connected to a number of radial headers at opposite ends of said tubes; and connections for fluid flow between the sub-headers in said rings and the supply and collecting headers.

2. In a boiler; a cylindrical casing having at opposite ends thereof an inlet and an outlet for admission and discharge of a fluid from which heat is extracted; a water supply header and a steam and water collecting header mounted within the casing and located in spaced relation on its longitudinal axis; steam generating tubes intermediate said headers disposed substantially in radial alinement in concentric rows about said axis with the tubes parallel thereto; a plurality of sub-headers radiating from said axis in pairs spaced axially of the casing and connecting with the upper and lower ends of radially alined tubes of said rows; a series of water distributing subheaders disposed in a ring about said water supply header and a second series of steam and water collecting subheaders disposed in a ring about said steam and water collecting header and each being connected to a number of radial headers at opposite ends of said tubes; and connections for fluid flow between the sub-headers in said rings and the supply and collecting headers; and downcomers parallel to the casing axis connecting the headers of the water collecting ring to the headers of the water supply ring.

3. In a boiler; a cylindrical casing having at opposite ends thereof an inlet and an outlet for admission and discharge of a fluid from which heat is extracted; a water supply header and a steam and water collecting header mounted within the casing and located in spaced relation on its longitudinal axis; steam generating tubes intermediate said headers disposed substantially in radial alinement in concentric rows about said axis with the tubes parallel thereto; a plurality of sub-headers radiating from said axis in pairs spaced axially of the casing and connecting with the upper and lower ends of radially alined tubes of said rows; a series of water distributing subheaders disposed in a ring about said water supply header and a second series of steam and water collecting subheaders disposed in a ring about said steam and water collecting header and each being connected to a number of radial headers at opposite ends of said tubes; connec tions for fluid flow between the sub-headers in said rings and the supply and collecting headers; downcomers parallel to the casing axis connecting the headers of thewater collecting ring to the headers of the water supply ring; and a water supply conduit extending past said steam and water collecting header and through said casing along its longitudinal axis within said rings of sub-headers to said water supply header.

4. A boiler as recited in claim 1 wherein the various radial headers are connected to said water supply and said steam collecting headers by tubular connections joined to said headers in spaced relation axially of said casing so that the connections to said headers are distributed axially of the casing so as not to [fOIlIl an obstruction in a plane transverse of said casing to the flow of heating fluid.

5. A boiler as recited in claim 1 wherein the generating tubes are vertically disposed and the radial subheaders connected to opposite ends thereof are divergently inclined from the outer ends to their ends adjacent the longitudinal axis of said casing.

6. A boiler as recited in claim 1 wherein the subheaders in each of said rings of sub headers are interconnected for fluid flow therebetween by loop tubes.

7. In a boiler; a cylindrical casing having at opposite ends thereof an inlet and an outlet for admission and discharge of a fluid from which heat is extracted; a supply header and a collecting header mounted within the casing and located in spaced relation on its longitudinal axis; heat absorbing tubes disposed substantially in radial alinement and arranged in concentric rows about said axis with the tubes parallel thereto; a plurality of radially extending sub-headers arranged in pairs spaced axially of the casing and connecting the upper and lower ends of radially alined tubes of said rows; and connections for fluid flow between said radial headers and the supply and collecting headers.

8. In a boiler; a cylindrical casing having at opposite ends thereof an axially located inlet and an axially located outlet for admission and discharge of a fluid from which heat is extracted; a cylindrical water supply header and a cylindrical steam and water collecting header mounted within the casing and located in spaced relation on the major axis of said casing; a plurality of concentric rows of steam generating tubes disposed substantially in radial alinement about said axis with the tubes parallel thereto and occupying substantially the full area of the cross-section of said casing except for a central space between said headers; a plurality of tubular connections from the side walls of said headers extending radially toward the inner wall of said casing and then parallel to the casing axis for connecting them with upper and lower ends of tubes in said rows; and tubular means for supplying to the outer end of said Water supply header and for withdrawing steam from the outer end of said collecting header.

9. In a boiler; a vertically disposed cylindrical casing having at opposite ends thereof an inlet and an outlet for admission and discharge of a fluid from which heat is extracted; a supply header and a collecting header mounted within the casing and located in spaced relation on its longitudinal axis; heat absorbing tubes disposed intermediate said headers substantially in radial alinement and arranged in concentric rows about said axis with the tubes parallel thereto; a plurality of radially extending sub-headers arranged in pairs spaced axially of the casing and connecting the upper and lower ends of radially alined tubes of said rows; connections for fluid flow between said radial headers and the supply and collecting headers, said radial headers at the upper and lower ends of said tubes being divergently inclined from their outer ends adjacent said casing to their inner ends adjacent the longitudinal axis of said casing.

10. A boiler as recited in claim 1 wherein the tubes in the outer concentric rows of generating tubes are of larger diameter than those in rows closer to the longitudinal axis of said casing and accommodated to their radial position so as to substantially fill the space about said sub-headers.

References Cited in the file of this patent UNITED STATES PATENTS 662,296 Palmer Nov. 20, 1900 1,766,989 Forssblad June 24, 1930 1,798,830 Brand Mar. 31, 1931 2,038,807 Synnott Apr. 28, 1936 2,672,849 Fruit Mar. 23, 1954

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