US3073575A

US3073575A - Air-cooled surface condenser

Info

Publication number: US3073575A
Application number: US682238A
Authority: US
Inventors: Schulenberg Franz
Original assignee: GEA Luftkuehler GmbH
Current assignee: GEA Luftkuehler GmbH
Priority date: 1957-09-05
Filing date: 1957-09-05
Publication date: 1963-01-15
Anticipated expiration: 1980-01-15

Description

Jan. 15, 1963 F. SCHULENBERG 3,073,575

AIR-COOLED SURFACE CONDENSER Filed Sept. 5, 1957 7 Sheets-Sheet 2 {gli} 'Eig l L @H Iglu E' l E EN@ h l' E El m E @l M l MS Fig. 2

NVENTOR ATTORNEY Jan. 15, 1963 F. scHuLENBERG 3,073,575

AIR-COOLED SURFACE CONDENSER Filed Sept. 5, 1957 7 Sheets-Sheet 5 J Zw HTTORNEH Jan. 15, 1963 F. scHuLl-:NBERG 3,073,575

AIR-comu SURFACE coNnENsER Filed Sept. 5, 1957 '7 Sheets-Sheet 4 in J# n, u' l; I l

' l ,li yd iIRI INVENTOF? HTTORNEJ F. SCHULENBERG AIR-COOLED SURFACE CONDENSER '7 Sheets-Sheet 5 /NvefNroR RTTRNEQ/ Jan. 15, 1963 Filed Sept. 5, 1957 Jan. 15, 1963 F. scHULl-:NBERG 3,073,575

AIR-COOLED SURFACE CONDENSER Filed Sept. 5, 1957 7 Sheets-Sheet 6 /lv VEN T0 R Jan. 15, 1963 Filed Sept. 5, 1957 F. SCHULENBERG AIR-COOLED SURFACE CONDENSER 7 Sheets-Sheet 7 Fig. l0

/NVEN TOR #TTD RNES/ 3,073,575 Patented Jan. 15, 1963 3,073,575 AIR-CGLED SURFACE CONDENSER Franz Schulenberg, Bochum, Germany, assgnor to Gea- Luftltuhler-Gesellschaft m.h.H., Bochum, Germany, a

firm

Filed Sept. 5, 1957, Ser. No. 682,238 7 Claims. (Cl. 16S- 146) The present invention relates to a surface condenser with a plurality of condenser elements connected in parallel as regards the steam to be condensed and cooled externally by a current of air maintained in positive circulation, in which condenser each condenser element has at least two rows of condenser tubes arranged substantially parallel to each other and one behind the other at a distance apart in the direction of flow of the cooling air. The condenser tubes of each condenser element are at the same time connected in parallel to a .common steam distribution chamber :and to a common condensate collecting chamber. The vaporous medium to be condensed, for example water vapor, is fed to the steam distribution chambers of the individual condenser elements through at least one `connection piece of a steam distribution conduit. Two to four or even more rows of condenser tubes are arranged one behind the other in the ow direction of the cooling air. The condenser tubes are generally constructed as ribbed tubts and may be of circular or elliptical cross section. The condenser tubes are brushed on their outer si-de by a current of cooling air drawn from the atmosphere and positively kept movingl for example by means of propeller blowers.

In the condensers of this type hitherto known the condenser tubes in all the rows arranged one behind the other in the direction of ow of the cooling air receive the same quantities of steam. As the tubes in the individual rows possess similar heat-exchanging surfaces, the objection arises that, owing to the drop in temperature becoming less from row to row in the direction of flow between the temperature of the steam entering the distribution chamber and that of the cooling air, the condensation in the individual rows varies very considerably. Whereas, for example, in the first row of tubes brushed by the cooling air the whole of the steam is already condensed at a relatively great distance from the end of the tube leading into the condensate collecting chamber, in the row of tubes last brushed by the current of cooling air the condensation process is only terminated in the neighborhood of the end of the tube leading to the condensate collecting chamber. Consequently, in the rows of tubes first brushed by the air current only a portion of the tube length is utilized for the condensation of the steam, whereas in the remaining section of the length of these tubes the condensate undergoes unnecessary undercooling. This cooling of the condensate below the condensation point has been found extremely disadvantageous especially in the case of low atmospheric temperatures, particularly heavy frost, because in the rows of tubes first brushed by the cooling air the condensate is cooled far below freezing point so that these tubes become completely choked by ice plugs. When the tubes of the row of tubes first brushed by the current of cooling air have become choked by freezing up, the cooling air comes within the range of the second row of tubes at a lower temperature, with the result that also in these tubes the boundary between the condensation range and the undercooling range is displaced towards the steam admission end owing to the greater drop in temperature available, and ice plugs also form there. The same procedure repeats itself at very low atmospheric temperatures of, for example, about 20 C., possibly also in the next following rows of tubes so that the condenser either becomes frozen upv entirely or its throughput capacity is reduced to a able extent.

In order to avoid the above-mentioned objections it is proposed, according to lthe invention, to adapt the heatvery considerexchanging surfaces of the condenser tubes in the rows of tubes arranged one behind the other in the direction of flow and/ or the steam distribution to the rows of tubes to the actually 4available drop in temperature between the steam admission temperature, in the neighborhood of the steam distribution chamber, and the cooling air temperature in such a manner that in all the rows of tubes the condensation is completed lat a short distance from the ends of the tubes leading into the condensate collecting chamber. This presents the advantage that subcooling of the condensate is avoided and the formation of ice plugs in cold weather cannot occur. Furthermore, a far better utilization of the available heat-exchaning surface is obtained, which is advantageous not only in the case of particularly low atmospheric temperatures but also in the case of higher atmospheric temperatures. Finally, by this arrangement, while subcooled condensate enters the condensate collecting chamber from the rows of tubes first brushed by the cooling air current, the condensation process in the last row of tubes situated at the end of the air current possibly in the neighborhood of the ends of the tubes leading into the condensate collecting chamber will not have terminated completely and some steam will still be sucked out of these tubes by the air exhausting device.

The invention can be applied for example in .such a manner that, while using condenser tubes of similar length, similar passage cross section and with similar heat-exchanging surfaces, at least the tubes in the row first brushed by the current of cooling air 4reecive a far greater quantity of steam, for example 1/4 to 2/3 more than the tubes of the rows of tubes arranged behind them in the direction in which the cooling air flows. It is, however, particularly advantageous yfor the quantities of steam admitted to the tubes of the rows of tubes arranged one behind the other in the direction of flow to be substantially proportionately equal to the drop in temperature actually available between the steam admission temperature in the neighborhood of the distribution chamber and the mean cooling air temperature in the range of the actual row of tubes. In order to obtain such steam distribution, devices for throttling the steam admission can be coordinated to the ends of the tubes leading into the steam distribution chamber. These devices may consist, for example, of nozzles or diaphragms fitted, if necessary exchangeably tted, in the tube ends leading from the steam distribution chamber. Such throttling arrangements are not necessary in the row 'of tubes first brushed by the cooling air, which tubes each receive a maximum quantity of steam.

The object of the invention can also be attained in that, when using condenser tubes of uniform passage cross section and uniform length, which receive the same quantities of steam, at least the tubes of the row of tubes rst brushed by the cooling air current have a heat-exchanging surface which, in relation to the quantity of steam passed through, is considerably smaller, for example by 1A to Va, than the tubes of the rows of tubes following thereafter. However, it is particularly advantageous in this case for the heat-exchanging surface of the tubes in the rows of tubes `arranged one 4behind the other in the direction in which the cooling air flows, to be dimensioned substantially inversely proportional to the actually available drop in temperatures between the steam admission temperature in the region of the distribution chamber and the mean cooling air temperature in the region of the actual row of tubes. To obtain a different heat-exchanging surface in the case of the tubes of the rows of tubes arranged following'each other in the direction in which the cooling air flows, the surface area and/or the spacing of the ribs in the individual rows of tubes can, when ribbed tubes are employed, be different.

According to another feature of the invention the tubes in the row of tubes irst brushed by the current of cooling air can, when using condenser tubes of the same length and with similar heat-exchanging surfaces, also have a considerably larger passage cross section, for example larger by M1, or 2/3, than the tubes of the rows of tubes arranged thereafter. In this case, however, it is particularly advantageous for the ow cross section of the condenser tubes in the rows of tubes arranged one behind the other in the direction in which the cooling air ows, to be dimensioned in the same ratio to the drop in temperature actually available between the steam admis sion temperature in the region of the distribution chainber and the mean cooling air temperature in the region of the actual row of tubes.

The object of the invention can also be attained by using a combination of two or more of the means indicated above.

Several preferred embodiments of the invention are illustrated by way of example in the accompanying drawings, in which:

FIG. l is a side elevation showing a complete condenser plant;

FIG. 2 is a top plan view and a horizontal section on line II--II of FIG. 1;

FIG. 3 is a vertical section, on a larger scale, on line III- III of FIG. 2;

FIG. 4 is a diagrammatic front elevation of a condenser element;

FIG. 5 is a vertical section on line V-V of FIG. 4;

FIG. 6 shows, on a larger scale, a portion of FIG. 5 with ribbed tubes and throttle nozzles inserted therein;

FIG. 7 shows, on a larger scale, a portion of FIG. 5 with throttle diaphragms inserted in the ribbed tubes;

FIG. 8 shows, on a larger scale, a section of FIG. 5 with a false bottom plate arranged in the steam distribution chamber and provided with apertures;

FIG. 9 shows the false bottom plate according to FIG. 8 in perspective view;

FIG. lO is a cross section through the upper part of a modified form of construction of a condenser element with tubes with different heat-exchanging surfaces, and

FIG. 1l is a cross section similar to FIG. l0 showing a condenser element with tubes with diierent passage cross sections.

As shown in FIGS. l and 2 a steam discharge conduit i from a steam turbine Z which drives, for example, an electric generator 3, is connected to a symmetrically branched steam feeding system 4. The branches of said steam feeding system 4 are of similar construction, the cross-sectional ow area of the steam feed conduit 4 being reduced in stages in proportion to the quantities 'of steam lcd ol, so that the flow speed of the steam along the `entire length of the steam feed conduit i is substantially the same. As can be seen from FIG. 1 the steam feeding system 4 connected to the discharge conduit 1 is laid under the oor and has four connection pieces 5 arranged at uniform distances apart and extending perpendicularly to the floor. Two diverging, similarly constructed and coaxially arranged

steam distribution conduits

6 and 6a are connected to each of the end connecting pieces 5 of the steam feed conduits 4. A double row of

condenser elements

7 and 7a is connected to each of the

steam distribution conduits

6 and 6a.

The

condenser elements

7 and 7a are, as can be seen from FIG. 3, arranged at an incline to each other in roofshape and connected at their ends close to each other to the

steam distribution conduits

6 and 6a extending in the longitudinal direction of the double rows. and at their ends away from each other to condenser collecting conduits and Sa extending parallel thereto. The

condenser elements

7 and 7a inclined towards each other .in roofshape form a substantially equilateral triangle in cross section, and on the base of this triangle propeller blowers 9 of relatively large diameter are arranged extending in a horizontal plane. The propeller blowers 9, as can be seen from FIG. 2, are arranged with but slight lateral clearance under the

condenser elements

7 and 7a united in double rows and are equipped with individual drives 1i) which can be adjusted independently of each other. ln this manner the number of revolutions of the individual propeller blowers 9 can be independently regulated. ln addition the angle of incidence of the blades of the propeller blowers can be adjusted, although this is not shown in the drawings, in order to be able in this manner to regulate the quantity of air delivered by the individual blowers independently of each other.

As can be seen from FIGS. 1 to 3, the

condenser elements

7 and 7a arranged on both sides of the connection pieces 5 of the steam feeding system 4 and united in double rows, are in each case arranged above a large suction chamber 11 open on all sides and which has suc tion apertures 12 extending substantially over their entire outer sides. The propeller blowers 9 suck air from the atmosphere through the suction apertures 12 provided in the sides of the suction chamber 11 and force it upwards in substantially vertical direction through the

condenser elements

7 and 7a arranged above the propeller blowers 9.

Instead of the

condenser elements

7 and 7a being arranged as shown in FIGS. 1 to 3, it is obvious that the invention can be carried out with condenser elements arranged in some other manner. The only important fac tor is that the condenser must have several condenser elements which are parallel connected in as far as the steam to be condensed is concerned and which are externally cooled by a positively circulated air current and in which each of the condenser elements has at least two rows of substantially parallel condenser tubes arranged one behind the other at a distance apart in the direction in which the cooling air stream is circulated, the condenser tubes of each condenser element being connected in parallel up to a common steam distribution chamber and to a common condensate collecting chamber.

An example of a form of construction of a condenser element of this type is illustrated diagrammatically in FIGS. 4 and 5. Each of the condenser elements has a relatively large number of ribbed tubes 13 of circular cross section arranged parallel to each other at a distance apart, which tubes, as can be seen from FIG. 5, are arranged infour

rows

14, 15, 16 and 17 connected up in series at a distance apart in the direction of the cooling air ow x. It is evident that two, three or more than four rows of ribbed tubes arranged one behind the other in the direction x in which the cooling air ows, can also be used instead of the four rows of series connected ribbed tubes 13. Moreover, it is also possible to use tubes of elliptical or oval cross section instead of tubes with cir cular cross section. In this case the tubes will be so arranged that their long cross-sectional axis lies in the direction x in which the cooling air tlows.

All the ribbed tubes 13 of each condenser element are connected at their upper end to a common steam distribution chamber 18 and at their lower end to a common condensate collecting chamber 19. The steam distribution chambers 1S of the condenser elements are connected to the

steam distribution conduits

6 and 6a by connection pieces 20 of large cross section extending substantially over the entire length of the steam distribution chambers 1S. The

steam distribution conduits

6 and 6a have, as can be seen from FIGS. 1 and 2, a cross-sectional shape tapering conically in the direction of ow y of the steam, the cross-sectional reduction being in proportion to the amount of steam led off to the condenser elements arranged side by side in the longitudinal direction of the

distribution conduits

6 and 6a. The steam to be condensedis fed via the connection pieces 20 in the direction a at a temperature of about 40 C. into the steam distribution chambers 18.

The condensate collecting chambers 19 of the condenser elements are connected to the condensate collecting conduits 8 and 8a by connection pieces 21. These connection pieces 2.1, contrary to those of the example illustrated in FIGS. 4 and 5, can have a considerably larger passage cross section. The condensate collecting chambers 19 are also connected by connection pieces 22 arranged laterally of the collecting chambers 19, to an air exhaust conduit 23 which leads to an air exhausting device 23a as can be seen from FIGS. l and 2. This air exhausting device 2351,*

constructed in known manner, produces the vacuum necessary for the condensation of the steam. In this arrangement a common air exhauster can be provided for all condenser elements of the condenser, but likewise a separate air exhauster may be provided for example for each of the

steam distribution conduits

6 and 6a. Moreover, it is also possible to utilize the condensate collecting conduits 8 and 8u at the same time as suction lines and Ito connect the air exhausting device or devices directly to the condensate collecting conduits S and 8a. With the aid of the air exhausting devices coordinated to the condenser, an absolute pressure of for example 0.05 atm. is produced in the condenser elements.

In the form of construction illustrated in FIGS. 4 and 5, the condenser tubes 13 of all rows of

tubes

14, 15, 16, 17 Vare all of the same length and have similar heat-exchanging surfaces and passage cross sections. The rows of

tubes

14, 15, 16, 17 are arranged parallel to each other and at the same distance apart. Each row of

tubes

14, 15, 16, 17 consists of a relatively large number of likewise parallel condenser tubes 13 arranged at the same distance apart in lateral direction.

In the case where the condenser tubes 13 of all the rows of

tubes

14, 15, 16, 17 receive the same quantity of steam, dierent condensation conditions exist in the individual rows of tubes owing to the different drop in temperature between the steam temperature in the region of the distribution chambers 18 and the cooling air temperature in the region of each individual row of

tubes

14, 15,16, 17. As the `drop in temperature between the steam and the air is relatively greatest in the tubes of the row of tubes 14 rst brushed by the cooling air, the condensation process in the tubes 13 of this row of tubes 14 already finishes at a relatively great distance from the ends of the tubes leading into the condensate collecting cham-ber 19. When all the rows of tubes are uniformly fed with steam, only the upper portion of the length of the condenser tubes 13 of the row `of tubes 1d, which is shown without cross-hatching in FiG. 5, is fully utilized for the condensation of the steam, whereas in the lower cross-hatched portion of the length of the condenser tubes of the row 14, the condensate is subjected to unnecessary undercooling. Owing to the fact that the drop in tempcrature between the steam temperature in the region of the distribution chamber 18 and the cooling air temperature in the region of the individual rows of

tubes

15, 16, 17 becomes less from row to row of the tubes, the boundary between the condensation region which is not cross-hatched and the subcooling region which is crosshatched is displaced more and more towards the ends of the tubes leading into the condensate collecting chamber 19.

In the case of the condensers hitherto generally 4used the strength of the cooling air current in relation to the actual atmospheric temperature is generally so chosen that the condensation process in the row of tubes 17 located at the end of the cooling air current, terminates near the lower end of the condenser tubes. Consequently, of the whole of the heat-exchanging surface of the condenser tubes 13 of the rows of

tubes

14, 15, 16 only the section located above the cross-hatched subcooled region is utilized for the condensation of the steam in the known condensers. In the case of low atmospheric temperatures,

6. for example 20 C. and below, ice plugs are formed in the subcooled zones and choke these tubes so that nally only the last row of tubes 17 in the direction of the cooling air current is available for the condensation of the steam.

In order to overcome these objections, throttle arrangements can be detachably tted in the ends of the tubes of the second, third and fourth rows of

tubes

15, 16, 17 in the direction x in which the cooling air `flows, which ends lead `from the steam distribution chamber 18, as illustrated in FIGS. 6 and 7. In the form of construction illustrated in FIG. 6 the throttle arrangements consist of

nozzles

24, 25, 26 which have a different passage cross section in the individual rows of tubes. The passage cross section of the condenser tubes 13 of the row or tubes 14 tirst -brushed by the cooling air current and also of the nozzles 24, v25, 26 of the rows of

tubes

15, 16, 17 is gauged in the same ratio to the drop in temperature between the steam temperature in the region of the steam.

distribution chamber 18 and the mean cooling air ternperature in the region of the actual row of

tubes

14, 15, 16, 17. Thus the condenser tubes in the rows of

tubes

14, 15, 16, 17 are supplied with `dilferent quantities of steam proportional to the drop in temperature between the steam admission temperature and the mean cooling air temperature actually available in the region of the actual row of tubes, so that in all the rows of tubes the condensate enters the condensate collecting chamber 19 at approximately the same temperature. At the samey time the strength of the cooling air current is adapted, by regulating the blowers 9 according to the actual atmospheric temperature, to the total quantity of steam to be condensed in a condenser element so that the condensation terminates inall the rows of tubes.14, 15, 16, 17 at a short distance from the ends of the tubes leading into the condensate collecting chamber 19, with -the result that no appreciable subcooling of the condensate takes place.

Instead of the

nozzles

24, 25, 26 used in FIG. 6, the steam distribution to the condenser tubes 13 of the individual rows of

tubes

14, 15, 16, 17 arranged one behind the other in the direction of ow x of the cooling air, can be regulated by diaphragrns 27, 28, 29 (FIG. 7) or by other devices narrowing the cross-sectional passage area of the tubes. The

diaphragms

27, 2S, 29 arealso detachably fitted in the ends of the tubes. In the case ot' elliptical ribbed tubes with end sections of circular cross section, the

diaphragms

27, 2S, 29 can also be loosely inserted in the ends of the tubes. The passage cross section of the condenser tubes 13 of the first row' 'of tubes 1a, as well as the diaphragrns 2.7, 2S, 29 of the rows of

tubes

15, 116, 17 is graded proportionately equal to the actually available dropI in temperature between the steam temperature in the region of the steam distribution chamber 18 and the mean cooling air temperature in the region of the actual row of tubes 14, 1:7, 16, 17. At the same time the strength of the cooling air current is also regulated, depending upon the actual atmospheric temperature, according to the total quantity of steam to be condensed in the condenser element so that the condensation terminates in all rows of tubes at a short distance from the ends of the tubes leading into the condensate collecting chamber 19. The condenser tubes 13 of ali the rows of

tubes

14, 15, 16, 17 are, in the form of construction illustrated in FIGS. 6 and 7, all of the same length, have similar heat-exchanging surfaces and, apart from the throttle devices 24 to 29 in their upper end, the same passage cross section. The radial ribs provided on the outer side of the condenser tubes 13 are designated by 30 and are all of the same surface area and distributed at uniform distances apart over the entire length of the condenser tubes 13.

In the form of construction illustrated in FIGS. 8 and 9, the condenser element also has four rows of condenser tubes 13 arranged one behind the other in the direction x in which the cooling air flows, which condenser tubes are all of the same length, have similar heat-exchanging surfaces and the same passage cross section. As can be seen from FIG. 8, a false bottom plate 31 extending substantially parallel to the plane of the tube mouths is arranged in the distribution chamber 18 and provided with

apertures

32, 33, 34, 35 opposite the mouths of the tubes. The passage cross section of these

apertures

32, 33, 34, 35 is progressively smaller from row to row of tubes in the direction x in which cooling air tiows, proportionately to the actually available drop in temperature between the steam admission temperature in the region of the steam distribution chamber 18 and the mean cooling air temperature in the region of the actual row of

tubes

14, 15, 16, 17. By this arrangement it is also possible for the condenser tubes in the rows of

tubes

14, 15, 16, 17 to be supplied with different quantities of steam which are proportional to the actually available drop in temperature between the steam admission temperature vand the mean coe-ling air temperature in the region of the actual row of tubes. The condenser tubes 13 are, in the example illustrated in FIG. 8, provided along their entire length with radial tubes 30 on their outer side.

In the case of the atmospheric temperature being for example 20 C. and the steam temperature for example +40 C. in the region of the steam distribution chamber 1S, susbtantially the following conditions can be assumed in the case of the forms of construction illustrated in FIGS. 6 to 9:

The mean cooling air temperature in the region of the individual rows of

tubes

14, 15, 16, 17 arranged one behind the other in the direction of ow x should, under the given conditions, be 15 C. for the row of tubes 14, 6.5" C. for the row of tubes 15, -0.5 C. for the row of tubes 16 and +35" C. for the row of tubes 17. In the rows of tubes the following mean drop in temperature is available for the condensation of the steam:

Row 14=55 C. Row 15=46.5 C. Row 16=40.5 C. Row 17=36.5 C.

The passage cross section of the nozzles 24 (FIG. 6) or of the diaphragms 27 to 29 (-FIG. 7) or of the aper- 32 to 35 in the false bottom 31 (FIGS. 8 and 9) are so stepped down that the quantities of steam distributed to the condenser tubes of the rows of

tubes

14, 15, 16, 17 are as 55:46.5:40.5:36.5.

The form of construction of a condenser element illustrated in FIGS. l and l1, is provided with three rows of

tubes

14, 15, 16 arranged one behind the other in the direction of flow of the cooling air x. In the example illustrated in FIG. the ribbed tubes 13 in the rows of

tubes

14, 15, 16 are all of the same length and have the same passage cross section. Furthermore, the ribbed tubes 13 in all the rows of tubes are supplied with the same quantity of steam. The heat-exchanging surfaces of the ribbed tubes are, however, of diterent `dimensions in the individual rows of

tubes

14, 15, 16. In the row of tubes 14 tirst brushed by the current of cooling air, the condenser tubes 13 have a heat-exchanging surface which is considerably smaller than that of the tubes of the row 15, the heat-exchanging surface of which is in turn considerably smaller than that of the row of tubes 16. Furthermore, the spacing of the ribs 30 in the individual rows of

tubes

14, 15, 16 differs in the form of construction illustrated in FIG. 10. It is however also possible, while retaining equal spacing in the individual rows, to make the ribs of different sizes. The heat exchanging surface of the condenser tubes 13 in the rows of

tubes

14, 15, 16 is inversely proportional to the available drop in temperature between the steam admission temperature in the region of the steam distribution chamber 18 not shown iin FIG. l0, and the mean 8, cooling air temperature inthe region of the actual row of

tubes

14, 15, 16. In the event of the available drop in temperature in the rows of

tubes

14, 15, 16 being 40, 30 and 23 C., respectively, the heat-exchange surfaces of the condenser tubes 1,3 -in the rows of

tubes

14, 15, 16 should be as l/40z1/3021/23.

In the example illustrated in FIG. 11, the condenser tubes 13 in ther ows of

tubes

14, 15, 16 arranged one bchind the other in the direction of flow of the cooling air x, are of the same length and have the same heat-exchanging surface area but have passage cross sections of difierent sizes. The passage cross section of the condenser tubes in the rows of

tubes

14, 15, 16 is proportionately equal in each actual row of tubes to the drop in temperature between the steam admission temperature in the region of the steam distribution chamber and the mean cooling air temperature in the region of said actual row of tubes, so that a steam distribution proportional to the actually available drop in temperature is set for the condenser tubes 13 of the rows of

tubes

14, 15, 16. ln the event of the drop in temperature between the cooling air and the steam in the steam distribution chamber being 40 C. in the region of the row of

tubes

14, 30 C. in the region of the row of

tubes

15 and 23 C. in the region of the row of tubes 16, the passage cross sections of the condenser tubes in the rows of

tubes

14, 15, I6 should be in a ratio of 40:30:23. The size of the surface area and the spacing of the ribs 30 of the condenser tubes 13 is so chosen in the individual rows of

tubes

14, 15, 16 that the heat-exchanging surfaces of all the condenser tubes are of the same size.

From the above detailed description of the invention, it is believed that the construction will at once be apparent, land while there are herein shown and describe/.l several` preferred embodiments of the invention, it is nevertheless to be understood that minor changes may be made therein Without departing from the spirit and scope of the invention as claimed.

I claim:

1. In a surface condenser for condensing steam by a stream of cooling air, in combination, a plurality of conduit means connected in parallel, each conduit means including a row of conduits for conducting the steam transverse to the direction of the stream of air, said rows of conduits being located in planes extending transverse to said direction and distributed along the length of the stream of air so that the stream of cooling air successively passes over the outer surface of each of said conduit means whereby the temperature of the air is increased, said conduits of each row of conduits being substantially identical, and having substantially the same heat-exchanging surface, and the conduits of all said rows of conduits being diiferently shaped and arranged in such a manner that the amounts of steam passing through each conduit separately, and through all conduits of each row across con- 'secutive equal portions of said stream of air decrease in said direction of the stream of air corresponding to the decreasing cooling capacity of the stream of air so that the condensate formed in each of said conduit means of the steam entering all said conduit means at the same temperature has substantially the same desired temperature.

2. In a vsurface condenser for condensing steam by a stream of cooling air, in combination, a plurality of conduit means connected in parallel, each conduit means in cluding a row of substantially identical conduits for conducting the steam, `said rows of conduits being located in planes extending transverse to the direction of the stream of air and being distributed along the length of the stream of air so that the stream of cooling air 'successively passes over the outer surface of each of said conduit means whereby the temperature of the air is increased; and throttling orice means arranged in said conduits for throttling the flow of steam through said conduit means, the throttling orifice means in the conduits of each row being substantially identical, and the throttling orifice means of all said rows lbeing differently shaped in such a manner that different amounts of steam flow through each of said conduit means and that the total amounts of steam passing through said conduit means across consecutive equal portions of said stream of air decrease in said direction of the stream of air corresponding to the decreasing cooling capacity of the stream of air so that the condensate formed in each of said conduit means of the steam entering all said conduit means at the same temperature has substantially the same desired temperature.

3. In a surface condenser for condensing steam by a stream of cooling air, in combination, a plurality of conduit means, each conduit means including the same number of tubes arranged in a row for conducting the steam transverse to the direction of the stream of air, said rows of tubes being located in planes extending transverse to said direction and distributed along the length of the stream of air so that the 'stream of cooling air successively passes over the outer surface of each of said conduit means whereby the temperature of the air is increased, said tubes being substantially identical; and throttling oriiice means for said tubes, the throttling orice means for the tubes of each conduit means being identical, and -the throttling orifice means for the tubes of dierent conduit means being dierently shaped in such a manner that different amounts of steam flow through each row of tubes and that the total amounts of steam passing through said conduit means acro'ss consecutive equal portions of said stream of air decrease in said direction of the stream of air corresponding to the decreasing cooling capacity of the stream of -air so that the condensate formed in each of said conduit means has substantially the same desired temperature.

4. In a surface condenser for condensing steam by a stream of cooling air, in combination, a plurality of conduit means, each conduit means including the same number of tubes arranged in a row for conducting the steam transverse to the direction of the stream of air, said rows of tubes being located in planes extending transverse to said direction and distributed along the length of the stream of air so that the stream of cooling air successively passes over the outer surface of each of said conduit means whereby the temperature of the air is increased, said tubes being substantially identical; and detachably mounted ythrottling orifice means for said tubes, the throttling orice means for the tubes of each conduit means being identical, `and the throttling orifice means for the tubes of different conduit means being diferently shaped in such a manner that different amounts of steam flow lthrough each row of tubes and that the total amounts of steam passing through said conduit means across consecutive equal portions of said stream of air decrease in said direction of the stream of air corresponding to the decreasing cooling ca- 10 pacity of the stream of air so that the condensate formed in each of said conduit means has substantially the same desired temperature.

5. In a surface condenser for condensing steam, in combination, blower means for producing a stream of air owing in a selected direction; a plurality of conduit means spaced different distances from said blower means, each conduit means including the same number of tubes arranged in la row for conducting the steam transverse to the direction of the stream of air, said rows of tubes being located in planes extending transverse to said ydirection and distributed along the length of the stream of air so that the stream of cooling air successively passes over the outer surface of each of said conduit means whereby the temperature of the air is increased, said tubes being substantially identical; and detachably mounted throttling orice means for said tubes, the throttling orifice means for the tubes of each conduit means being identical, and the throttling orifice means for the tubes of different conduit means being differently shaped in such .a manner that different amounts of steam flow through each row of tubes and that the total amounts of steam passing through said conduit means across consecutive equal portions of said stream of air decrease in said direction of the stream of air corresponding to the decreasing cooling capacity of the stream of air so that the condensate formed in each of said conduit means has substantially the same desired temperature.

6. A surface condenser as set forth in claim 1 wherein said conduit means have different cross sectional areas decreasing in said direction of the lstream of air.

7. A surface condenser as set forth in claim 1 wherein said conduits of the first row of conduits in the direction of said stream of air over which the air passes first have cross 'sections one quarter to two thirds greater than the cross sections of the row of conduits next following in said direction of the stream of air.

References Cited in the file of this patent UNITED STATES PATENTS 1,597,720 Carrier Aug. 31, 1926 1,627,265 Bancel May 3, 1927 1,760,505 Lea May 27, 1930 1,915,805 Sutcliie June 27, 1933 2,006,649 Modine July 2, 1935 2,107,478 Happel Feb. 8, 1938 2,263,397 Rathbun Nov. 18, 1941 2,587,720 Fritzberg Mar. 4, 1952 2,613,065 Didier Oct. 7, 1952 FOREIGN PATENTS 732,492 Great Britain Iune 22, 1955

Claims

1. IN A SURFACE CONDENSER FOR CONDENSING STEAM BY A STREAM OF COOLING AIR, IN COMBINATION, A PLURALITY OF CONDUIT MEANS CONNECTED IN PARALLEL, EACH CONDUIT MEANS INCLUDING A ROW OF CONDUITS FOR CONDUCTING THE STEAM TRANSVERSE TO THE DIRECTION OF THE STREAM OF AIR, SAID ROWS OF CONDUITS BEING LOCATED IN PLANES EXTENDING TRANSVERSE TO SAID DIRECTION AND DISTRIBUTED ALONG THE LENGTH OF THE STREAM OF AIR SO THAT THE STREAM OF COOLING AIR SUCCESSIVELY PASSES OVER THE OUTER SURFACE OF EACH OF SAID CONDUIT MEANS WHEREBY THE TEMPERATURE OF THE AIR IS INCREASED, SAID CONDUITS OF EACH ROW OF CONDUITS BEING SUBSTANTIALLY IDENTICAL, AND HAVING SUBSTANTIALLY THE SAME HEAT-EXCHANGING SURFACE, AND THE CONDUITS OF ALL SAID ROWS OF CONDUITS BEING DIFFERENTLY SHAPED AND ARRANGED IN SUCH A MANNER THAT THE AMOUNTS OF STEAM PASSING THROUGH EACH CONDUIT SEPARATELY, AND THROUGH ALL CONDUITS OF EACH ROW ACROSS CONSECUTIVE EQUAL PORTIONS OF SAID STEAM OF AIR DECREASE IN SAID DIRECTION OF THE STREAM OF AIR CORRESPONDING TO THE DECREASING COOLING CAPACITY OF THE STREAM OF AIR SO THAT THE CONDENSATE FORMED IN EACH OF SAID CONDUIT MEANS OF THE STEAM ENTERING ALL SAID CONDUIT MEANS AT THE SAME TEMPERATURE HAS SUBSTANTIALLY THE SAME DESIRED TEMPERATURE.