US2961221A

US2961221A - Heat exchange apparatus

Info

Publication number: US2961221A
Application number: US532827A
Authority: US
Inventors: George F Friese; Justin P Winkin
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1955-09-07
Filing date: 1955-09-07
Publication date: 1960-11-22
Anticipated expiration: 1977-11-22

Description

1960 G. F. FRIESE EI'AL HEAT EXCHANGE APPARATUS 2 Sheets-Sheet 1- Filed Sept. '7. 1955 FIG.'5

INVENTORS GEORGEF. FRIESE BY JUSTIN P. WINKIN ATTORNEY Nov. 22, 1960 G. F. FRIES'E ETAL HEAT sxcnmcs: APPARATUS 2 Sheets-Sheet 2 Filed Sept. 7, 1955 INVENTORS GEORGE F. FRIESE BY JUSTIN P. WINKIN ATTORNEY United States Patent HEAT EXCHANGE APPARATUS George F. Friese, Barberton, Ohio, and Justin P. Winkin, Fair Lawn, N.J., assignors to The Babcock & Wilcox fompany, New York, N.Y., a corporation of New ersey Filed Sept. 7, 1955, Ser. No. 532,827

1 Claim. (Cl. 257-227) The present invention relates to heat exchange apparatus, and more particularly to a heat exchanger of the type in which mercury vapor is condensed and steam is generated thereby.

Mercury vapor has been used in the past as a heat transfer medium, particularly in the generation of power from the heat energy in the mercury vapor. A mercury turbine is ordinarily operated under condensating conditions with at least a partial vacuum created in the condenser. The condensation of mercury vapor releases great quantities of heat, and when water is used as the condensating medium the mercury vapor condensation is accompanied by the generation of large quantities of steam.

When mercury vapor is used as a heat exchange medium in any system of heat transfer, whether for power generation purposes or not, one of the problems always involved in the mercury vapor condenser is the thermal expansion and contraction of the condenser parts. This problem is rather difficult to solve, particularly in view of the fact that the mercury vapor is ordinarily generated and delivered to the condenser at a much lower pressure than the steam generated by the condensation of the mercury.

In accordance with our present invention we provide a mercury vapor condenser and steam generator which is characterized by its efficient heat transfer characteristics while at the same time the relative expansion and co traction of the parts with-in the heat exchanger are guided in their movements so as to avoid the creation of ex cessive stresses and strains in the related parts.

The various features of novelty which characterize our invention are pointed out with particularity in the claim annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descrip tive matter in which We have illustrated and described a preferred embodiment of the invention.

Of the drawings:

Fig. 1 is an elevation, in section, of a heat exchanger constructed and arranged in accordance with the present invention;

2 is a horizontal section taken on the line 22 of Fig. 1;

Fig. 3 is a horizontal section taken on the line 33 of Fig. 1;

Fig. 4 is an enlarged vertical section of a portion of the apparatus shown in Fig. 1;

Fig. 5 is a horizontal section taken on the line 5-5 of Pig. 4; and

Fig. 6 is a further enlarged section or" the outlet header shown in Fig. 4.

The heat exchanger shown in the drawings is of the general type disclosed in a co-pending application Serial No. 532,826, filed September 7, 1955, now Patent 2,890,684, granted June 16, 1959, in the name of Justin P. Winkie, wherein mercury vapor is used as a heat trans- "ice fer medium for process heating purposes. As disclosed in that application excess mercury vapor generated in the mercury vapor generator is discharged to the heat exchanger with the liquid mercury thereafter returned to the mercury vapor generator.

As shown in Fig. 1, the heat exchanger 19 includes an elongated cylindrical pressure vessel 11 which is provided with dished upper and

lower ends

12 and 13, respectively. The upper end or the vessel is provided with a manhole 14 and a cover 15 for access to the interior of the vessel 11;. A steam outlet pipe 19 extends through the upper end 12 of the pressure vessel. The customary safety valve and vent connections (not shown) are also provided in the upper end 12. The lower end 13 of the vessel is provided with a downwardly extending cylindrical cap 16 having a tapered end section 17 which merges into a downcomer tube 18 for the discharge of water from the vessel 11. The cap member is provided with a flanged side sleeve 20 for the insertion of a feed water pipe 21. The feed water pipe extends through the sleeve 20 to an elbow 22 with the elbow provided with an upwardly extending tube which opens into the cylindrical vessel 11 at a position above the lower end 13. In addition a second tube is inserted through the side of the cap member 16 to an elbow 24 horizontally spaced from the elbow 22, and an upwardly extending tube 23 which projects within the vessel 11 to a position intermediate its height. The latter tube 23 is used for the introduction of chemicals to the water maintained in the lower portion of the pressure vessel 11.

The upper portion of the vessel 11 is provided with side inlet connections 25 for the admission of steam and water through riser tubes (not shown), where the steam and water ascending through the riser tubes may originate from a waste heat boiler such as disclosed and claimed in the co-pending application Serial No. 532,826. Inwardly spaced from the wall of the pressure vessel 11 is positioned 9. depending baffie 26 which extends from a position immediately below the riser tube connection 25 to an annular oafiie member 27 formed between the up right baffle 26 and the wall of the pressure vessel 11. The upright bafile 26 extends through a segment of the circumferential wall of the pressure vessel 11 equal to approximately 200 degrees. In its installed position, the bafiie 26 serves to deflect the incoming steam and water from the riser tubes in a downward direction along the walls of the pressure vessel so as to afford steam and water distribution within the pressure vessel. A blowdown pipe 29 is provided intermediate the height of the shell 11 for the continuous or intermittent removal of steam and water from the pressure vessel.

A plurality of tube bundles 28 are positioned in the intermediate portion of the pressure vessel 11 for the movement of mercury vapor and liquid through the tubes and in indirect heat exchange relationship with the water and steam maintained within the pressure vessel. The tubes of the tube bundles 28 open at their upper and lower ends into mercury vapor inlet headers 34 and mercury outlet headers 31, respectively. Mercury vapor is delivered to the tube bundles 28 through a plurality of. circumferentially distributed inlet pipe connections 32 each of which connects with a separate mercury vapor header 39. The mercury vapor is delivered to a distribution manifold (not shown) from one or more sources of supply with the manifold serving to deliver substantially uniformly distributed streams of mercury vapor to each of the circumferentiaily distributed iniet conduits 33 leading to each of the connections 32. In the embodiment of the invention illustrated there are eight tube bundles 28 with each tube bundle including a group of ten tubes.

The mercury vapor delivered to the tube bundles 28 passes through the inlet conduit 33 within the connection 32 which is constructed as a thermal sleeve for extension of the inlet conduit through the wall of the pressure vessel 11. Thermal sleeves, per so, are well known, and in the present instance are constructed of a short tube length having an internal diameter larger than the external diameter of tube inserted therethrough. The external large diameter tube is welded at its outer end to the small diameter tube, and on its inner end is welded to the external wall of the pressure vessel 11. As shown, each of the conduits 32 is supported on the wall of the pressure vessel internally of the vessel wall by a bracket 34. As hereinafter described substantially all of the weight of the tube bundles 28, with the mercury vapor and liquid therein, is supported on the shell of the vessel 11 from the upper end of the conduits 33.

j As shown particularly in Fig. 4 the inlet header 30 of .each of the tube bundles 28 is formed with a frustoconical upper portion 35 which is welded to the lower portion which forms the tube sheet 36 for the tubes. The upper end of the frusto-conical portion 35 is provided with a cylindrical neck 37 which is welded to the lower end of the inlet conduit 33. The tubes 38 of the bundle 28 are Welded to the inlet header 30 and are spaced in a pattern such as shown'in Fig. 5.

The lower ends of the tubes 38 are inserted into the tube sheet 40 portion of an inverted cup-like member which is welded to a corresponding upwardly opening cup member 41 to form the lower header 31. A single mercury liquid discharge tube 42 opens into the lower portion of the outlet header 31 so as to provide a liquid mercury discharge means for the mercury condensed in the tube bundles. Each of the outlet tubes 42 is formed with a goose neck configuration having a lower leg or member 43 which is generally horizontal, but is given an upward inclination from its fixed outlet position in the shell 11 of the condenser-boiler, when the assembly is originally installed. As hereinafter described, thermal expansion of the tube bundles 28 with their connecting piping will cause the outlet header 31 to move in a downward direction so that the generally horizontal member 43 of the outlet tube 42 will assume a downward inclination from its fixed position relative to the drum outlet. The goose neck tube 42 is shaped to accommodate the thermal expansion of'the entire tube bundle assembly 28 wihout serious overstressing of any part of the outlet tube 42.

i The inlet end 44 of the outlet tube 42 is extended above the inner lower surface 45 of the outlet header 31 so that a pool of liquid mercury is maintained on the lower surface 45 of the outlet header. Thus, as mercury vapor is condensed in the 'tube bundles and discharged downwardly into the outlet header 31 the droplets of mercury will impact a pool of mercury and avoid the erosive efiect of liquid mercury striking metallic surfaces under high velocity conditions. A section of the outlet header 31 is shown in detail in Fig. 6 where the complementary halves of the header are welded together approximately inte med ate the hei ht of the assembled header. The lower end portions 46 of the tubes 38 passing through the tubesheet 41 are welded to the internal surface of the tube sheet. With the construction described a strong assembly is formed which will maintain a tight structure to avoid leakage of mercury vapor into the water and steam contained in the heat exchanger even under the operating conditions encountered. As shown particularly in Fig. l the structure of the outlet opening 47 in the pressure vessel shell 11 for the liquid mercury discharge tube 42 is provided with a thermal sleeve similar to the thermal sleeve of the connection 32 hereinbefore described.

With the described vertical movement of the tube bundles 28 and their inlet and

outlet headers

30 and 31, due to thermal changes in the elements, means are supplied tor guiding the bundles in their vertical movement so as to retain their position relative to the vessel during such movement. As shown in Figs. 1 and 3 a guiding linkage for the tube bundles 28 is provided adjacent the outlet headers 31. The linkage includes a pivotal connection between each of the four circumferentially spaced brackets i; welded to the shell 11 of the condenserboiler, and an arm 51 which extends between a pair of adjacent tube bundles 28. The inner end of the arm 51 is pivotally attached to bracket elements 52 welded I bundles includes a separate pair of brackets 53 welded to the headers which are pivotally connected to an arm p of the condenser-boiler.

54 extending radially across the condenser-boiler 10 to a corresponding pivotal connection with brackets 53 attached to tube bundle headers 31 on the opposite side The radially extending arm 54 is provided with an offset member 55 which is fitted to the upper end of the chemical inlet pipe 23. The outer 'most pairs of tube bundles 28 are also connected by a linkage arm 56 pivotally connected to brackets 57 welded on the exterior side of the outlet headers.

With the assembly described vertical movement of the tube bundle assemblies, as caused by thermal expansion and contraction, is flexibly guided so that the horizontal relationship of the tube bundles is maintained throughout the temperature range of operation.

While in accordance with the provisions of the statutes we have illustrated and described herein a preferred embodiment of the invention, those skilled in the art will understand that changes may be made in the method of operation and form of the apparatus disclosed without departing from the spirit of the invention covered by our claim, and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

What is claimed is;

A fluid heat exchanger comprising a vertically elongated pressure vessel having inlet and outlet means for water and steam, and means for heating the waterin said pressure vessel including a plurality of closed heat exchange units positioned within said pressure vessel, each unit including an upper and lower header connected by a group of spaced substantially upright tubes, a separate inlet pipe opening to each of said inlet headers and projecting through an upright wall of said pressure vessel, each of said units separately pendently supported from the Wall of said pressure vessel by said inlet pipe, a separate outlet pipe for condensed mercury opening from the outlet header of each of said units, each of said outlet pipes having a reverse bend portion therein within said pressure vessel and a horizontally extended portion projecting through an upright wall of said vessel, and linkage means interconnecting the outlet headers of said units with the upright wall of said vessel to guide the vertical thermal movements of said units with respect to the wall of said pressure vessel, including circumferentially spaced wall brackets attached to the wall of said vessel, header brackets attached to each of said headers, a pivotal connection between adjoining header brackets of adjacent headers, an arm pivotally interconnecting eachrof said wall brackets with the pivotal connection between said adjoining header brackets, and an arm connecting a pivotal header bracket connection with a corresponding pivotal header bracket connection on the opposite side of said vessel.

References Cited in the file of this patent UNITED STATES PATENTS (Other references on following page) 5 UNITED STATES PATENTS Davy Oct. 18, 1932 Lucke et a1. Oct. 25, 1932 Lucke July 18, 1933 Huber Apr. 17, 1951 6 Brown June 2, 1953 Moore Aug. 4, 1953 Bielfeldt Oct. 13, 1953 Mayhew Dec. 29, 1953 Lloyd Dec. 21, 1954