US2376505A - Heat exchange apparatus - Google Patents

Description

May 22 l945- J. P. RATHBUMN ErAL l2,376,505

' HEAT EXCHANGE APPARATUS l Filed June 30, 1943 2 Sheets-Sheet .1 v

INVENTORS JoHN i? RA-z-HBUN, MzLLARD ANELSQN. Y

ATroRNEY May 22, 1945. L R RATHBUN ET AL 2,376,505..

AHEAT EXCHANGE APPARATUS INVENTORS .JOHN P, RATHBU N MLLLARD R.N:-:1 SON.

ATTORNEYV Patented May 22, 1945 2,376,505 HEAT EXCHANGE APPARATUS John l. Rathbun, Prospect Park, and Millard A.

Nelson, Sharon Hill, Del., assignors to Westnghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application June 30, 1943, Serial No. 492,822

4 Claims;

' This invention relates to heat exchange ap- Y paratus of the vertical type, more particularly to `vertical heat exchangers incorporating sub-cooling sections, and has for an object to provide irn- 4proved apparatus of this character.

In`order to obtain emcient operation of subcooling sections of heat exchangers, it is necessary to prevent leakage of steam to such section from the remaining portions of the heat exchanger, as such leakage of steam would ra-ise the temperature of the condensate therein, thereby defeating the purpose bf the sub-cooling section.

Therefore, another object of the invention is to provide, in vertical heat exchangers having a portion of the irst waterpass partitioned olf as a sub-cooler, novel means for water-sealing the partition against leakage of gases therepast.

A further object of the invention is to provide novel means for preventing water hammer or similar unstable action in a vertical heat exchanger.

These and other objects are eifected by the invention as will be apparent from the following .description and claims taken in connection with ing in the direction indicated by the arrows;

Fig. l4 is a Vertical sectional View of a modified construction, taken along the line IV-IV of Fig.

5, looking in the direction indicatedv by the arrows;

Fig. 5 is a transverse sectional view taken along the line vV--V of Fig. 4, looking in the direction indicated by the arrows; and, A

Fig. 6 is an enlarged Afragmentary sectional view, taken alongthe line VI-VI of Fig. 4, looking in the direction indicatedby the arrows.

Referring Vnow to the drawings more in detail,

particularly Figs. 1, 2 and 3, there is indicated in its entirety, by the numeral III, a heat exchanger comprising a shell I I, having plurality of tubes I2 of U shape extending longitudinally thereof with their terminal portions extending into and supported by tubesheet I3, which forms apart of water box structure I4. The water box structure includes a vertically-disposed, diametrically extending partition I8 (Fig. 2) dividing the space within the water box into an inlet chamber II having an inlet connection I8, and an outlet chamber I9 having an outlet connection 20, this chamber construction providing for flow of water through the tubes in a plurality of passes.

The shell II is provided with a steam inlet 22 and a condensate outlet 23. Thelower end of the shell is closed by the water box structure I4 and the upper end by suitable structure, such as the dome 24, formed integral therewith or welded "or bolted thereto. Preferably, the dome 24 is provided with suitable vent means, at 25, to assist in establishing 'circulation of steam through the apparatus. Also, there is provided an impingement baille 26, extending in front of and in spaced relation to the steam inlet 22,v to preventinjury to the tubes by the entering steam.

The space surrounding the coldest or lower portion of the tubes of the iirst water pass is ltheir outer vertical edges with suitable sealing and nuts 4I.

means 32, (Fig. 2), preferably of the Lamiex type. This seal 32 performs the added function of preventing leakage of steam from the con- 'densing space to the sub-cooling space.

It is seldom desired to use the entire length of the first water pass for a sub-cooling section, and, therefore, a horizontal partition, indicated in 'its entirety by the numeral 34, is provided at the upper limit of thesub-cooling section. As bestindicated in Fig. 3, this partition 34 comprises upper and lower plates 35 and 36 respectively. having disposed therebetween a packing member 3l. The horizontal partition 34 is sealed about its edges by upper and lower seal strips 38,

held in place by pressure strips 39, the members 35, 36, 31, 33 and 39 being retained in. assembled relation by suitable means, such as the bolts 40 The horizontalv partition 34 is provided with openings 44 therethrough flor the passage of the tubes I2.

It will be noted that the horizontal partition is positioned slightly below the upper edges of the radial partitions 29 and 30, with the result that the portions of these partitions extending f above the horizontal partition 34 provide a dam structure, serving toretain onv the `horizontal ypartition condensate ilowing down or falling from the portions ofthe tubes I2 extending thereabove. Condensate is collected on this horizontal partition to seal the clearance spaces between the tubes I2 and the openings 44 in the partition, against leakage of steam therethrough from the condensing space to the sub-cooling section, which leakage would occur due to the lower pressure existing within the sub-cooling section if the body of condensatewas not maintained on the horivzontal partition.

opening for discharge of condensate collecting onthe horizontal partition 34. The condensate overilowing through the `opening 50 passes downward through'the conduit 48 to the bottom of the shell, where it passes out through the opening 52 in thetube plate I3, and through the passage 53 forming in the enlarged central section of the partition |6, for ilow through the conduit 55 to the inlet connection 56 at the upper end of the sub-cooling section. Preferably, an impingement baille 61 is disposed in spaced relation tothe in ner end of the inlet connection 56 to prevent damage of the tubes Fby the entering condensate. Also,` there is preferably provided suitable vent .means 58 for air and noncondensable gases at the upper end of the sub-cooling -section in order that the lattermay be maintained substantially l full of condensate at all times.

said partition flooded, is frequently insuillcient.` to "v l satisfactorily seal the latter against leakage of valve nem-member sz' to return the valve 6| to closing position.

Ina'smuch as the volume of the condensate which can be obtained from the condensing portions of the tubes ofthe liirst water pass overlying the horizontal partition 34, for maintaining steam therepast, this inventiony provides means for supplementing this supply of condensate. To

- this end, the shell Il lis provided with an inlet connection 68,positioned to discharge vdirectly onto the horizontal partition 34 condensate respectively, as best shown in Fig.2. It will be seen To further insure ofthe sub-cooling section being maintained ilooded throughout operation, there isprovided, in the outlet connection 23 of the, sub-cooling section, a flow-control valve 60, operated through linkage 6| by the float mem-v -ber 62, housed in the oat container 63. housing is connected by conduits 64 and 65 `to This the interior of the shell II and tc the body of condensate within the shell, respectively.` Thus,

r condensate isv permitted to discharge from the Isub-cooling section only when the volume of con- Y densate within, the shell reaches a predeter-T,

mined level, thereby maintaining the sub-cool- As a result of the connections 64 and 65 between the chamber 63 and the interior of the steam space on Vthe one hand andthe con' densate space on the other, the level of "conden- .sate in 63 will correspond with the level within or above the conduit 53, disposed-centrally of the closed, the condensate will ll the conduitSS, the conduit leading therefrom, and the subcoollng section.- in its entirety. -It is possible to water box. with the subeooler outlet valve soI maintain these parts ooded withcondensate 1 Y even though the level of the latter in the chamber 63 is materially lower than portions of thev flooded parts, due to thehigher pressure existing at and above the condensate level within the i' .shelland chamber 63 than exists at the .outlet 23 of the subcoollng section. As soon as the condensate level rises in the chamber 63, the consequent raising of the float 62 results in opening of the valve 60 to permitcondensate to be forced tnrougnthe conduits sa and ss and the subeool'- ing section until the level in the shell and the chamber 83 has droppedsuiiiciently to cause the turxiedfrom a separate higher pressure heat exchanger 69. Preferably, an impingement baille 10 is provided toprevent damage to the tubes I2 by the entering condensate.

In order to' provide for devious flow of the steam from the steam inlet 22, there are provided a plurality of horizontally disposed ballles 13 and l'14, arranged in alternating, vertically-spaced relation and provided with openings 15 and 16rethat the openings 15 are located at theopposite ends from the openings 16 in the alternate bailles, with `the result that devious ow of steam is insured.

To; avoid water hammer -.or other unstable action resulting from counterrilow of rising steam and falling condensate, the cross-comer partition' 41 is provided with al plurality of openings 11,- disposed. adjacent the upper surfaces of the horizontal bailles 13 and -14, and through which openings condensate collecting on said bailles may flow to the vertical conduit 40, for passage to the bottom of the shell and thence to the subcooling section. v

In Figs. 4, 5 and 6 there is mustrated e modication of the present invention wherein, instead of supplementing the sealing condensate, for the horizontal partition at the/upper end ofthe subcooling section, by flashing condensate from an external source, there is provided means'for collecting wi-thin a central vertical conduit, theconz, densate collecting on bailles disposed above the horizontal partition, and then directing this condensate from the central conduit to the horizontal partition to maintain the latter flooded.

Referring now to' Figs. 4, Sand 6, there'is shown a heat exchanger, indicated in its entirety by the numeral |0I, comprising a shell |02 having a steam inlet. |03 and a condensate outlet |04; AA. plurality o f tubes- |05, extendingvertically within the shell, have their terminal portions supported by a tube plate |06, forming-aportion of awater box structure |01. The water box structure is divided into an inlet chamber I0 andan outlet cham-ber 'I|I, the chambers having inlet and outlet connections H2 and III, respectively, and providing for flow of water through the tubes inv a plurality of passes.

The space within the shell |02 is f bisected by va vertically-extending, diametrica'lly-dlsposed :partition H5. Radially-extending, 'verticallydispcsed partitions I|6 and I|1 cooperate 'withthe partition ||5 todivide the space within the 'e shell into quadrants. A pair of cross-comer partitions III-and H9 cooperate witha supplementary radial partition |20 to provide a triangulai-` central conduit |2|, extending from a point ne; r

the top of the shell tothe 'bottom thereof. The

partitions |I1 and |20 are preferably provided with I axniilex sealsat their outer edges in orde.

that they may be withdrawn' from the shell with the tube bundle.

. sgevasos The space enclosed by the partitions '||1, llly and serves as a sub-cooling section, whichhas its upper limit determined by a horizontal partition, indicated in its entirety by the numeral |22. Comparison of Figs. y3 and 6 will show that the 'structure of the horizontal partition |23 (Fig. 6) is identical withthat of horizontal par: tition 24' (Fig. 3),'and. therefore, no detailed description of the` partition |23 is deemed neces- The central partition IIB is provided at its lower edge with one or more openings |24 for.

passage ot steam from the lowei` right-handL quadrant to the lower left-hand quadrant, as viewed in Fig. 5. A

In order to provide for devious llow of steam through the apparatus, there are .provided alternating horizontally-disposed baflles |25 and. |26. l The cross-corner partition ill is provided with a. plurality of openings |21 opposite the upper sur'- taces of the tailles |25 and |20, whereby condensate collecting on the latter mayflow into the vertically-disposed central conduit |2|. A barrier |28 is provided within the conduit |2| a short distance above the horizontal partition |22. An outlet opening |29 is'provided in the partition ||l at the upper surface of the barrier |20, whereby condensate iiowing down the central conduit l2 l iiows out through the opening |20 onto the horizontal partition |23 to maintain -the latter flooded. A return inlet opening |20 is provided in the partition H0 slightly above the horizontal partitionI |22, in order that when the condensate on the partition reaches the level of said openlng |30, itwillV ilow therethrough back. to the central conduit |2|, for discharge through the passage |2| in the waterbox structure and the conduit |02, to the upper end ot the sub-cooling section. l

Discharge oi condensate from the-sub-cooling sectloniis controlled by a discharge valve |22,

,. operated through linkage |20, by the. iioat |25 housed in the chamber Illa. This chamber is in communication with the' interior or th orion and with the body of condensate in the shell. by conduits |20 and |21, respectively'.

Preferably, the baille |20 which overlies the shorter bundle of tubes is provided withia vent opening |20. and the shell dome is provided with vents |40 at each side o! the diametrlc partition Likewise, there is preferably provided a vent |41 at the upper end o! the sub-cooling section. y 5

Steam admitted to the shell through the inleiv |02 (Fig. 5) rises throughthe. northeast quadrant oi the shell. crosses horizontally beneath the horizontal baile [2l containing the vent 'Ill (Fig. 4) flows down through the southeast quadrant to the bottom ot the shell where it crosses through lthe openin'g'i in thepartltion ||l for upward ilow through the southwest quadrant and r thence across and downthrough the northwestl quadrant until it reaches the horizontal indivl sec structure |22 et the t'oplo! the subeooling While the inventionhaebeenshownin but one lform. it will be obvious tothoee skilled in the art that it is not so limited. but is susceptible ct various other changes and modilieations without departing from the spirit thereot. audit iedeaired, therefore, that only such limitations shall be placed thereupon arespecincally intheappendedclaims. t Whltllwmdll:

set forth .50 sowing in the conduit.

l. Heat exchange 'apparatus comprising avertically-disposed-shell having a steam inlet and a condensate outlet; a plurality 'of tubes extending vertically in the shell; means providing cloprouiding for flow of water therethrough in a .plurality of passesimeans separating the space surrounding the lower portions of thetubes of the l0 ilrst water pass from the -remainding space in i. the shell, said means including a horizontal 5 suresfor the ends of the. shell and includingwater box structure associated with the tubes and' partition having openings through which .said

-- tubes extend, said separated space including the condensate outlet and constituting a sub-cooling 15 section; means for conveying condensate from the bottom of said remaining space in the shell to the upper portion of the `sub-cooling section; and

means for water-sealing the subcooling section .Lgaiiistv leakage oI-steam therelnto through the 2'0 clearance between the-tubes and the wallsyofmthe openings -in the horizontal partition through! which said tubes extend, said last-mentioned means comprising a dam projecting above said 'horizontal vpartition adjacent the periphery 25 thereon to retain thereon condensate formed on tal partition. condensate trom-a heat exchanger loperating at higher pressure than exists in said shell.

3. Structure the means for supplementing the condensate collected on` the horizontal partition for sealing purposes comprises a plurality or horizontally-disposed ballies spaced vertically within the shell -at higher levels than. said horizontal partition. a vertical conduit disposed in `iuxtaposition rela- 45 tion to said bafiles and the horizontal partition and having openings therein adjacent the upper suriaces of the bailies for now or condensate' thereinto from said bailles, and means iorrdirecting onto the horizontal'partitlon the condensate e.' Structure as specied in claim,` l, wherein the means for supplementing the condensate col-` lected onthe horizontal partition tor sealing purposes comprises a plurality or horizontallyfdis- 554 posd bailes spaced vertically within the shell at higher levels' than said horizontahpartition; a vertical conduit disposed/in juxtaposition relaas' specii'ledin claiml, whereiny tion to said bellies andto tnelhorizontal partition Ind hlvln 096311138 thl'in adjacent 'the so uppersurtaeesorthebamesioriiowotcondensate thereintorromsaldbadies;abariierwithinthe conduit a short distance above the horizontal partition. saidrcondult having an outlet opening above seidbsrrler anda return inlet opening,

below said barrier andabove the horilontal partitlon, whereby condensate uowing in said conduit is ,caused by said to .discharge throughseidoutletontosaidhorlsontal' partition andtoreturntothecondultbelowthebarrier' 7o through seid return inlet opening.'

Joint P. immun s. unison.

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