US1721287A

US1721287A - Condensing apparatus

Info

Publication number: US1721287A
Application number: US204345A
Authority: US
Inventors: Ulrich A Taddiken
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1927-07-08
Filing date: 1927-07-08
Publication date: 1929-07-16
Anticipated expiration: 1946-07-16

Description

July 16, 1929. u. A. TADDIKEN CONDENSING APPARATUS Filed July 8, 1927 e; INVENTORA A U.^:rad,di|(en l Fu.. BY ce' ATTORNEY WITNESSES Patented July 16,

UNITED sms ULRICH A. TADDIKEN,OF PHILADELPHIA,` PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

coNnENsrNe APPARATUS.

application sied :muy e, 1927. semi No. 204,345.

My invention relates to heat exchangers and like apparatus, in which condensation, or in which ebullition and condensation take place, and it has for an object to improve the etliciency of apparatus of this character.

The air and other non-condensable gases, or vapors, which are present in the gaseous media lpassed into heat exchangers, such as surface condensers and the like, not only preclude the possibility of obtaining a perfect vacuum, but also tend to retard circulation and topi-event complete condensation of the condensable gases.

Condensation leaves the non-condensable on the condensing surface, from whence they must be removed by proper circulation. The quantityof non-condensable gases to be so removed, of course, increases with the progress of gaseous media through a nest of cooling' tubes, so that, in the later stages of the process, the non-condensable gases, which are also relatively7 poor conductors of heat, comprise va substantial proportion of the gaseous media present.

' Hence, toward the completion of the process of condensation, the non-condensables, due to their low conductivity, tend to form an insulating medium and to delay the condensation of the condensable vapors approaching the condensing surface, and thus, also to retard circulation.

Furthermore, the non-condensable gases exert a pressure which directly affects the vacuum obtainable. According to Daltons law of partial pressures, the pressure within a condenser, for example, is the total pres sure of the gaseous mixture, or the summation of the partial pressures due to each of the respective gaseous constituents.

For example, assume the temperature at any point within a condenser to be 101O F., and that for each pound of steam there is present 1/4 of a pound of air, a condition which is not uncommon. At 101O F. a pound of steam occupies 341 cubic feet. rIhis same space then, also contains 1/4 of a pound of air. The pressure of steam at 1010 F. is approximately 2 of mercury, which correspends to a vacuum of 29.92-2 or 27.92 inches. l

However, the partial pressure due to the air is .81 inchesof mercury. From Daltons law then', the total pressure is 2-l-.31 or 2.31 inches of mercury, which corresponds to a vacuum of only 29.92-231 or 27.61 inches.

.downflow condensers l With one pound of air per pound of steam, i

which is a possible condition, the pressure due to the air would be 1.24 inches of Inercury, under the same circumstances, and the vacuum would only be 26.68 inches. It will readily beseen, therefore, that the kpartial pressure of the air has a very appreciable effect upon the vacuum, and that every precausion should be taken to prevent the air and other non-condensable gases from accumulating, or concentrating iny any p0rtion of a condenser. f

{Ifsome of the gaseous media which conta-ins a relatively high proportion of the noncondensable gases is removed. from an exchanger of the type described, the surface of n this portion of the exchanger becomes more effective, due to the fact that` gaseous media containing a lower proportion of non-condensable gases may reach this surface.

Furthermore, if the gaseous media, so removed, is introduced into the exchanger at some point where the proportion of noncondensable gases is somewhat lower, the proportion of non-condensable gases present in the gaseous media throughout the exchangerv becomes more uniform, the effect of the relatively low conductivity of these gases and of their partial pressures becomes less, and their concentration in certain regions. is avoided.

More particularly, therefore, an object o my invention is to provide means for removing gaseous media from a portion of a condenser in which the proportion of non- Condensable gases is relativelyhigh and for passing the media so removed into the condenser in some region where the non-con densable gases are less concentrated, so that the mixture containing` lthe relatively high proportion of non-condensables may be assimilated by a larger volume of gaseous media having a somewhat lower contentvof non-condensables.` y

Apparatus embodying features of my invention is shown in the accompanying draw` ings, in which;

l Figs. 1 and 2 are transverse sections of Figs. 8 and 4 are transverse sections ofradial-flow condensers; and, y

Fig. 5 is a detail view of a connection .for removing gaseous media from the condenser shown in Fig. 4. i

According to my invention, any suitable i media withdrawn from the condenser has practically the same temperature as the condensate which serves as the cooling` media for the auxiliary heat exchanger, and hence it is assured that the withdrawn gaseous media will pass through this auxiliary heat exchanger and be recirculated through the nest of condensing tubes.

Referring now to the drawings for a better understanding` of my invention, I show, in Fig. 1, a straight down-flow condenser 10, comprising a shell 11, having a motive fluid inlet 12,'and` provided with a hotwell 13. rIhe nest of cooling tubes 14 is separated, by the longitudinally-extending baffle 16, to provide a cooling chamber 17 for cooling the air and other non-condensable gases previous to their removal through the air removal connection 18.

rIhe operation of the apparatus thus far described is well understood, motive fluid exhaust being passed into the shell through the inlet 12, passes through the nest of cooling tubes 14 where the motive fluid exhaust is condensed. As the gaseous media progresses through the nest 14, the continuous removal of the condensable vapors `by condensation leaves a progressively increasing proportion of airand other noncondensable .gases in the nest of cooling tubes, with the result that, in the lower portions o-f the tube nest 14, there is a tendency for the non-condensables to collect, or to become somewhat concentrated.

In order to prevent this condition, I provide suitable fluid translating apparatus here shown in the form of steam-operated ejectors 21, which are disposed along the bottom of the condenser shell on either side ofthe hotwell'. One or more of these ejectors may be used, depending upon conditions, but, preferably, one such ejector and its associated connection are disposed on each side ofthe hotwell 13. Since the function of each of these ejectors is the same, only one will be described.

The ejector 21 is of the usual form and comprises an entraining chamber 22, a steam jet 23 and a diffuser 24. The entraining chamber 22- is connected with the lower portion of the tube nest 14 by the connection 26, this connection 26 being protected from the rain of condensate by a cowl, or the like, 27, so that during the operation of the ejector, gaseous media may be drawn under the cowl 27 and through the connection 26 to the entraining chamber 22 of the ej ector,

from whence it is removed through the diffuser 24.

In order to recover the heat of the motive fluid which passes through the jet 23 to actuate the ejector 21, I connect the diffuser 24 to the steam space of a suitable heat exchanger 29, which is of the surface type, and is provided with a longitudinally-extending baflle ,31 for preventing gaseous media from by-passing from the diffuser 24, through a portion of the nest, and to the connection 32 which is provided for the removal of .gaseous media.

The condensate removal pump 33, for

the main condenser is arranged to dischargey into the connection 34, which connects with the circulating system of heat exchanger 29, the condensate being discharged from the heat exchanger 29 through the connection 36. In this way, it is possible to recover the heat of the motive fluid which issues from the jet 23 of the ejector 21 and entrains the gaseous media in the entraining chamber 22. The entrained media, having practically the same temperature as the condensate, which is used as cooling media in the exchanger 29, will, of course, not be condensed in the heat exchanger 29, but will pass around the baflle 3l and out from the heat exchanger 29 through the connection 32, from which it pases into the tube `nest 14 at somesuitable point, as at'the connection 37. A baille 38 is arranged to. depend from above the connection 37 so as to protect the tubes of the nest 14, which are adjacent to the connection 37, from any vibration which might be caused by the passage of gaseous 'media through this connection.

The condensate, after passing from the connection 36 of the heat exchanger 29, may be utilized in any suitable manner, as for boiler feed water.`

The condenser shown in Fig. `2, and also the apparatus shown for removing gaseous media from the tube nest 14,l are in all respects similar to the arrangement shown in Fig. 1, with the exception that the heat exchanger 29 is omitted. In this case the entraining fluid which issues from the jet 23l of the ejector 21, as well as the gaseous media which is entrained, is passedl directly from the diffuser 24 through the connection 32 into the nest of tubes 14 the entraining fluid as well as any condensahle 'vapors in the'entrained fluid being condensed' in the nest 14.

In this case, the heat of the motive fluid which actuates the ejector 21 is not recovered, but the general improvement in the operationv of the condenser is brought about as before. The cost of this apparatus isA less than that shown in Fig.v 1, due tothe elimination of the heat exchanger 29;

In the arrangement shown'in Fig. 3, ar rae lOl) dial-flow condenser 40, comprising a shell 41, having a motive fluid exhaust inlet (not shown) is provided With a hotwell 43. A portion of the tubes of the nest 44 are separated from the condensing portionof the nest by spaced plates 46 and 47, to provide v a cooling chamber 48 for cooling theair and the other non-condensable gases, previous to their removal through the air removal connection 49. The inner side, or portion, of this chamber is closed by a rain plate'or the like, 51, which rests on the upper ends of the plates 47, While the lower 'portion of the plates 46 are secured to the shell, the space between the plates 46 and 47 providing aV passage for gaseous media from the condens-- ing portion of the'tube nest 44 tothe cooling the cooling chamber 48 so that a portion of the gaseous media. Which enters the cooling chamber maybe removed bythe ejector 21 and returned to the tube nest 44 through connection 53, which, in this case, is for convenience arranged to pass the media into the tube nest 44 along a lower portion thereof. It will be observed 'that inasmuch as this is a radial-flow condenser, the path of vapor travel is substantially the same forgaseous media at any point about the periphery of the nest of cooling tubes.

In Fig. 4, a radial-flow condenser 54, comprising a shell 55, having a motive fluid exhaust inlet 576, is provided `With a hotvvell 57. rIhe air and non-'condensable gases are removed from the nest of cooling tubes 58 through the removal connection 59, Which is protected from the rain of condensate bya rain plate 61.

In this form of apparatus, the connection 26 of the ejector 21 is connected to relatively short, longitudinally-extending pipes 62, by means of the connections 63 and 64. These pipes 62 appear in longitudinal elevation in Fig. 5, from which it Will be observed that the open ends of the pipes are undercut, or biased, so as to permit gaseous media to enter either end of these pipes and to pass therefrom, through the respective connections 63 and 64, to the connection 26, While the projecting' upper ends of the pipes serve to prevent condensed media from passing into these connections. The media Withdrawn by the ejector, as Well as the entraining fluid, then passed from the ejector throughthe connection 66 and into the nest 58 for recirculation.

will be observedthat gaseous media is re-` moved only afterit has passed through a considerable portion ofthe nest of cooling tubes, and thus it is assured that the media so removed Will contain as large a content of non-condensables as Willfbe found in gaseous media in any portion of the condenser, and that this media is re-introduced into the nest of condensing` tubes at the point Where the proportion of non-condensable gases Will be relatively loW. In this Way itis possible to provide for maintaining a more uniform condition throughout lthe nest of cooling tubes,this vbeing accomplished by mixing gaseous media having a high content of noncondensables with gaseous media having a relatively loW content of non-condensables. It will thus be seen that I have'provided means for preventing they non-condensable gases from concentrating in any portion'of a heat exchanger, and for assuring improved conditions for vapor flow and for maintaining the desired vacuum; A It will also be obvious that my invention may be embodied in existing forms of condensing apparatus Without any material alterationsin such apparatus. Y l i i Furthermore, the air removal vapparatus is left to function as before, so that it is assured that the proper conditions of flow will be obtainedin J[he vicinity of the air removal connection, which, of course, Would not be the case if the ioiv of gaseous media Were merely accelerated byv this' apparatus in an endeavor to yprevent theconcentration of the non-condens'able gases.

lVhile I have shown the heat exchanger29 only in connection with a. down-flow condenser, it will be understood that it is Within the province of my invention to `provide similar heat ,exchangersl for radial flow condensers. l v Y While I have shown my invention in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other` changes and modifications Without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims. I

What I claim is 1. The combination With a nest of tubes, of means for directing gaseous media through the nest, and means for re-circulating some of the media through the nest.

2. The combination with a nest of tubes, of means for directing gaseousr media through the nest, fluid translating means for withdrawing uncondensed media from the nest, and means for passing media discharged by said fluid translating means into the nest.

In Fig. 4, as Well as in the other views, it 3. A device of the type described comprisiso ing a shell having an inlet for oondensable gases, a nest of tubes within the shell, fluid translatingmeans connected to the shell at a point remote from said inlet, and means providing a passage from the discharge of the fluid translating means to the nest of tubes. Y

4. The combination with a surface condenser comprising a shell having a motive fluid inlet, a nest of tubes kwithin the shell, and an olitake for airl and non-condensable gases, of fluid translating means having an inlet in a path of vapor travel to said ofi'take, and means for passing media discharged by said fluid translating means to the nest of tubes.

5. The combination with a surface condenser comprising a shell having a motive fluid inlet, a nest of tubes within the shell, and an-offtake for air land non-condensable gases, of Huid translating means having an inlet in a path of vapor travel to said offtake, a passagef'or passing media discharged by said fluid translating means to the nest of tubes, and cooling means interposed in said passage.

6. The combination with a surface con` denser comprising a shell having a motive fluid'inlet, a nest oftubes within the shell, a hotwell for the shell, and an offtalie for air and non-condensable gases, of fluid translating means having an inlet in a path of vapor travel to said offtake, a passage for conducting media discharged by said fluid translating means to the nest of tubes, cooling means interposed in said passage, and means for supplying cooling media for said cooling means from the hotwell.

v 7 The combination with -a tubular heat exchanger having a condensing portion and a eoolingportion arranged for passing gaseous media therethrough in series', of means 8. The combination with a tubular heat exchanger having a condensing portion and a cooling portion arranged for passing gaseous media therethrough in series, of fluid en` training means for withdrawing gaseous media from the eduction side of the condensing portion, means for recovering heat from the entraining fluid, and means for recirculating the withdrawn media through the condens ing portion.

9. The combination with a tubular heat exchanger having a condensing portion and a cooling portion arrangedfor passing gaseous media therethrough in series, of fluid entraining means for withdrawing gaseous media from the eduction side of the condensing portion, means for transferring heat from the entraining fluid to condensate from the condensing portion, and means for recirculating the withdrawn media through the condensing portion.

10. The combination with a tubular heat exchanger having a condensing portion and a cooling portion arranged for passing gaseous media therethrough in series, of an ofi'- take for removing air and non-condensable gases from the cooling portion, and means for withdrawing gaseous media Vfrom the region substantially between said condensing and said cooling portions and for diverting the media so withdrawn away from both the condensing portion and the cooling portion.

In testimony whereof, I have hereunto subscriped my name this 23rd day of June, 192

ULRICH A. TADDIKEN.