US2004075A - Evaporator, especially for high pressure steam - Google Patents

Description

I June 4, 1935. VE. KOENEMANN El AL 2,004,075

EVAPORATOR, ESPECIALLY FOR HIGH PRESSURE STEAM Filed Jan. 4, 1952 3 Sheets-Sheet l I Imuemiom a A I l: v Emmi'Koanemann Dy Kaxl Genaa/h June 4, 1935. E. KOENEMANN ET AL 2,004,075-

7 EVAPORATOR, ESPECIALLY FOR HIGH PRESSURE ,STEAM Filed Jan. 4, 1932 3 Sheets-Sheet 2 Inuanioz-s Etna! Kaanemamn Karl Gauze];

4: M, haw v M ihaivAfimmeys fig. 3

June 4, 1935. E. KOENEMANN El AL 2,004,075

EVAPORATOR, ESPECIALLY FOR HIGH PRESSURE STEAM Filed Jan. 4, 1932 5 Sheets-Shet 3 Inuemfors Elma/1' Koelwmann y Kali Gan sta]:

their Akin/1710.79

* high boiling Patented June 4, 1935 UNITED STATES PATENT OFFHICEI 'EVAPORATDR, ESPECIALLY FOR HIGH PRESSURE STEAM Ernst Koenemamr and Karl Gensclr, Berlin,

Germany, assignors to Gesellschaft iiir Drucktransformatoren toren) G. in. b. IL, B ration of Germany (Koenemann-Transformaerlin, Germany, a corpo- 9 Claims.

This invention relates to an evaporator, especially for the generation of high pressure steam, heated by means of a liquid medium having a point, as for instance a fused salt- :i like chloride of zinc ammoniacate, and has as its main object a particular model of such an evaporator in which water and steam are prevented from penetrating into the heating medium through leakages at the points where the water tubes are joined to the collecting chambers by a rolling or welding process. Furthermore it is possible by our invention, in case of leakage. at any of the joints between the water tubes and the heating jacket containing the heating fluid, to easily perceive which joint is defective andto calk it without difficulty. At the same time it is provided that thedifierent degrees of expansion and contraction ;of the various members of the evaporator do not cause detrimental stresses in the material. Further details of the invention are. hereinafter described and illustrated in the attached drawings in which Figs. 1 and 2 show diagrammatically one illustrative embodiment of the invention, Fig. 1 being a longitudinal section through the evaporator, the upper part of Fig. 2 a plan seen from above, and the lower part of Fig. 2 a section at the line II--II of Fig. 1. Figs. 3 and 4 show a second embodiment of the invention, Fig. 3 being a side view of a part of the evaporator, and Fig. 4 a section at the line IV-IV, of Fig. 3. Figs. 5, 6, 7 a r ustrate a third embodiment of the invention, in ch-Fig. 5 is a side view of the evaporator, Fig. 6 aview from above, and Fig. 7 is a fractional section at the line VII--VH of Fig. 6, and Fig. 8 is a fractional section at the line VIlI-V]II of Fig. 5; Figs. 7 and 8 are drawn at a larger scale than Figs. 5 and 6. g V

'll'the evaporator consists of the following main pa s: I

The water tubes I, the collecting chambers 2 and 3 into which the water tubes are inserted, and the heating jacket encasing the water tubes along the greater portion-of their entire length.

In the model illustrated by Figs. 1 and 2 the water tubes are arranged as two concentric circles. The collecting chambers 2 and 3 are small vertical drums of comparatively small dimensions arranged in the. centre of the circle. The upper and lower ends of the water tubes are'curved inward at their ends and are atpoint 6 fixed-to the drums 'by a rolling or welding process. The

heating jacket is a double wall cylinder consisting of the outer wall 4, the inner wall 'I' and the annular top and bottom plates 8 and 9. At A \the cylinder has a-longltudinal slot and therefore the outer and inner casings 4 and 'l are there connected with each other by casing plates I0 and ll. a

The water tubes are inserted between the walls 4 and I of the jacket and perforate the top and bottom plates 8 and 9 at the points marked I2, where they leave the heating jacket. At the perforating points I2 the water tubes are welded to the jacket, i. e. in any usual or suitable way as by electric or flame welding or by rolling or expending the metal to form a rolled, expanded, or calked joint, or a stufiing box is inserted at each of these points. On the outer wall 4 are the 15 flanged sockets l3 and I4 through which the heating fluid is supplied and discharged.

This fluid is heated in a separate vessel and continually kept circulating from the vessel to 20 the evaporator and back by means of a pump. a The heating medium enters into the heating jacket through one of the sockets, flows along the water tubes and after having delivered heat to them is discharged from the heating jacket and returns to the heating vessel. Heating vessel, pump and the pipe-lines connecting the heating vessel and the heating jacket are not illustrated in the drawings.

The heat delivered by the heating fluid causes the water in the water tubes to evaporate. The mixture of steam and water resulting therefrom. flows into drum 2 where the main part of the water carried along is collected and flows through the downcomer 5 to the lower drum 3 from which it is supplied to the various water tubes. The steam is discharged at the socket piece l5, subject, if necessary, to superheating in a special device and then supplied to a turbine or used for any "other purpose. The necessary feed-water is 40 supplied to the evaporator through the socket piece I 6.

If guide-plates are arranged in the interior of the heating jacket to direct the flow of the heating liquid in such a manner that first of all only a part of the water tubes are heated by the hot fluid delivered by the heating ,vessel, and the remaining tubes are heated later on, then, owing to the difierence in temperature between heating liquid and water being greater at the inlet then at the outlet, the quantity of steam produced in the first-heated tubes is very much higher than that produced in the rest, which is only very small. One could therefore omit the downcomersbecause the water tubes which are only moderately heated would serve as downcomers. In such a case or course these water tubes must open into the drum 2 below water level.

The assembling of the evaporator can take place as follows:

The top and bottom plates provided with the necessary holes for theuwater tubes are put over the water tubes not yet bent and provisionally fixed at half height of the tubes, the ends of which thereupon .are curved inward and finally;

fixed intothe drums 2 and 3 by a welding or rolling process. The top and bottom plates 8 and 9 are then brought into their correct position, the .tubes are welded on at the points where they perforate the plates, and after that the. top and 1 bottom plates and the walls 8, I, I 0 and of the jacket are welded together or joined by riveting. The inner wall I consists of different sections which are inserted in the interior through the slot A between the walls l0 and I I, and thereupon welded or riveted to form the cylindrical wall I of the jacket.

structing such evaporators, the new construction described herein possesses the following advantages: Should the rolled or welded points of junction 6 of the water tubes commence to leak the steam or water seeping through will become noticeable at once, and the points of leakage can be made tight without delay. Neither water nor steam can come in contact with the heating liquid because the heating jacket is arranged in such a manner that it does not encase the points of junction 6. This is an important advantage, as the steam would be liable to disintegrate the heating fluid, especially as the temperature occurring in practice ranges at 660 F. and higher and together with the heating fluid would corrode the iron parts. This would happen with oils having a high boiling point, as well as with fusions'of salts. The same advantage will be realized at points l2 where the water tubes perforate the top and bottom plates 8 and 9. of the heating jacket. In case of leakages occurring at these points no water or steam can enter the heating jacket, even if some of the heating fluid should seepfout.

Above all the new design offers a possibility of repairing leakages at the points of perforation by ,Je-welding or re-caulking, or by re-packing and tightening the stufling boxes, should the tubes be provided with such stuffing boxes. All previous constructions lacked this possibility because the points'where the water tubes perforate the heating jacket, are too close together to permit repairs. In our constructions as described hereinabove, the boiler tubes are arranged as two concentric circles having such a diameter that all the water tubes of an evaporator can be accommodated. Consequently it becomes possible to subject all perforations l2 to a careful control and continual supervision, and the perforations are well accessible from all directions and can be therefore worked upon for repairs with the necessary tools.

The opening A forming a. slot along the heating jacket'is not only important for the purpose of an easy assemblage of the inner wall I, but it also makes it possible to compensate tension strains existing in the casings of the jacket, which strains are due to possible differences of temperature. Tensions between the jacket and water tubes on the one hand, and the drums connected with each other by the downcomer on the other hand,

are absorbed by the curve ends of the water tubes.

If necessary. the downcomer can be provided with acompensation neck such as the neck 26 shown on Fig. 5,

In the illustrations 3 and I another model of the evaporator is demonstrated. The corresponding parts of the evaporator are indicated by the same indexes as in Figs. 1 and 2. The water tubes l are arranged vertically and h e curved ends.

They open into the horizontal (1%: and 3 and ed in- The are welded on at the points 6, or

tybes are grouped as 4 sections having two rows each. Each group of pipes is encased in a boxlike heating jacket consisting of the side walls 4 and 1, the top and bottom plates 8 and 9, and the frontal plates l0 and II. The side plates 4 and I run parallel to the axes of the drums. The I height of the boxes corresponds to the length of the heating tubes, their .width to the length of the drums 2 and 3, and their depth is somewhat wider than the sum of the distance between the two rows of tubes and their diameters. The

' points where the heating jacket is perforated by As compared with the usual methods of con-- the water tubes, are marked l2. Everyone of the above mentioned four boxes has a flanged socket l3, and another socket M for the heating liquid at the other end of the box which is not illustrated. The steam is conveyed from the upper drum through the socket piece IS, the feed water is supplied through socket piece iii of the lower drum. Upper and lower'drums are connected by several downcomers 5. I

The advantage of the invention is particularly evident in this manner of construction. If all tubes would lead from drum 2 tothe lower drum within a single boxlike heating jacket and with all tubes lying close together as rows, a control of the rolled joints 6 and the points of perforation I-2. would perhaps be possible, but a repair of the points of perforation would be impossible, if a leakage should occur. In the new construction within each jacket not more than two rows of tubes are arranged. These jackets are at such a distance from each other that the points of perforation I! of the water tubes into the heating jacket are quite accessible and repair work can be carried out at any time.

The assembly of the evaporator can take place in the same manner as already described in the first model of construction as shown in Figs. 1 and 2. Here also one would first of all slide the top and bottom plates over the ,as yet straight water tubes. The water .tubes would thereupon be curved at their ends and then be fitted to the drums by a rolling or welding process. Now the top and bottom plates 8 and 9 are put into their correct position arid the side walls 4, 1, l0 and II are joined to them by welding or riveting.

A third model is illustrated by Figs. 5, 6, 7 and 8.

The water tubes I are in this construction placed closely together forming a bundle of tubes encased by the cylindrical part d to which on the top and bottom conical parts l'i are attached, and upon which subsequently the cylindrical parts l8 having a considerably larger diameter than the part 4 are fixed. The parts 4, H and I8 form the heating jacket together with the top and bottom plates 8 and 9. The different parts 4, 11, I8, 8 and 9 of the heating jacket are either welded or riveted together, or they are joined by flanges, as shown in our'drawings. The water tubes l ,are bent'outwards at their ends and emerge from the There are so many different planes that on each level only a restricted number of water tubes emerge from the jacket. On the other hand the diameter of the cylindrical section I8 is so large that each of these perforations I 2 is so far distant from the next, that everyone of them is easily accessible from all sides. The perforations in each plane can be arranged vertically one below the.

other forming several groups, the perforations of each group being situated always on two closely neighboured generatrices of the cylinder l8. In the drawings they are alternating chevronwise from right to left forming several groups of two I closely neighboured generatrices of the cylinder The number of planes can of course be varied, and a smaller or greater number can be used. Of course then the diameterof the cylindrical part I 8 must be chosen in accordance smaller or larger, in order that the distances of the perforation points be the same as before. The tubes leaving the jacket enter at 6 small chambers, 2 and 3, four of which are arranged on top, and four below.

From the chambers 2 downcomers 5 lead to the lower chambers 3. It is, however, advisable that the downcomers do not lead to that chamber which is situated vertically below the upper chamber in question, but to a neighbouring one, whereby the downcomer 5 is provided with two curved parts serving as compensating necks. The steam from the several chambers 2, together with such water as has not separated out and passed into the down comers 5, is injected through the pipe-lines l9 to the steam drum 20. The steam is then delivered by the socket 2i. The deposited water flows through pipe 22 into a small collecting vessel 23 into which the feed water flows through the pipe 24. The water is supplied to the water tubes I through the pipe-lines 25 which connect the drum 23 with the lower chambers 3; The heating fluid enters the heating jacket through'the socket l3, and leaves it through the socket H or vice versa. The heating jacket is provided with a compensation rib 26 which serves to compensate tensions and stresses due to heat differences existing bewater or steam cannot seep into the heating fluid. Furthermore the points I2 where 'the water-tubes tween the heating jacket and the water tubes.

The mounting of the evaporator can take place so that part 4 and the conical parts I! of the heating jacket are slipped over the water tubes prior to the latter being curved. The cylindrical part I8 is made of separate parts welded or riveted to each other and with the water tubes. Inside of the heating jacket, the water tubes can be kept in their correct position by suitablejmeans.

This model of ,construction is superior to other constructions by its particularly'low rate of flow resistance regarding the heating fluid within the heating jacket. Another advantage is that all of the water tubes are arranged closely together, the

cubic contents of the heating jacket consequently being very low and the required quantity of heating fluid thereby remaining small. N evertheless the advantageous'features of other models have been alsolmaintained in this our construction. The joints 6 between the water tu ",perforate the heating jacket, are at such a distance from each other that all tubesare accessible near the points of perforation and can'be repaired from every direction. V

Without altering the nature of this invention it'is also possible to put into practiceother models of the invention. For instance in the model illusaxis of the drum, and not said set readily accessible from trated in Figs. 5, 6, 7 and 8 the water tubes can be passed through the top and bottom plates 8 and 9 of theheating jacket. In this case, however, it would be advisable to arrange the points where the water tubes pass through the heating jacket so that they form pairs of concentric circles which alternatingly are close together or far distant from each other. Annular collecting chambers would then replace the difierent small collecting chambers 2 and 3, one annular chamber to be arranged above and one below each heating jacket. v Furthermore as an alternative in the model shown in the Figs. 3 and 4 the box-shaped heating jackets can also be arranged at a 90 angle to the 7 parallel to this axis, as

is illustrated in Figs, 3 and 4.

It is thus clear thatour invention may be em- I multiplicity of water tubes arranged in a plurality of continuous rows extending within said jacket and through a wall thereof, a collector spaced from said jacket and into which said water tubes lead, said water-tubesv having their multiplicity of points of passage through said jacket wall disposed so as to render all said points of passage through said jacket wall readily accessible from practically all directions.

2. An indirectly heated evaporator according to claim 1, the said disposition ofthe multiplicity of points of passage of said multiplicity of watertubes through said jacket being arranged in rows, and said rows being arranged in one or more passage of said water-tubes througli's'aid' jacket beingin two rows, i. e. paired rows, with the tubes of the respective rows in alternating chevronwise arrangement, substantially as described.

4. An indirectly heated steam generator or the like, of the type comprising upper and lower collector drums, upcomer tubes surrounded by a heating jacket and at least one downcomer tube; constructed with said upcomer tubes arranged in a plurality'of continuous adjacent rows passing through the wall of said jacket and traversing a sfiace before passinginto the collector drums, so t at leakage at either set of points'of passing will' not result in leakage of heated fluid into heating fluid or vice versa, and said omer tubes being groups with but a small number, as two, rows to arranged at at least one of said sets of points of passing so as to render all points of passing of practically all directions.

5. A heat exchanger of the class described, comprising a jacket having a portion of relatively.

small cross-section intermediate. its end portions and having its end portions enlarged to a relatively greater size, a multiplicity of tubes extending through said jacket and projecting through the walls of its enlarged end portions, those -portions of said tubes lying within the intermediate portion of said jacket being arranged in relatively closely spaced relation,

and those portions of the in a plurality of groups with but a small number, as two, rows to the group, and the structure of said heat exchanger providing access to said groups at both sides thereof.

'7. A heat exchanger according to claim 5, said :tubes extending through and beyond the walls of said jacket in two rows, 1. e. paired rows, with the tubes of the respective rows in alternating chevronwise arrangement, and the structure of said heat exchanger providing access to said paired rows at both sides thereof.

"8. An evaporator according to claim 1, said heating jacket having a relatively large portion and a relatively small portion, said tubes lying closely adjacent one another withinsaid relatively small portion, said tubes passing through the wall of the relatively large portion, said enlargement providing for separation of the tubes before their passage through said wall and thereby providing for their disposition as aforesaid.

9 An evaporator according to claim 1, said jacket having a central portion and widened end portions, said tubes extending through said central portion closely adjacent one another, and said tubes bending within said widened end portions and extending through said jacket wall at points laterally of said widened end portions with the points of passage thereof disposed as aforesaid.

ERNST KOENEMANN. KARL GENSCH.

Images