US1721261A - Condenser - Google Patents

Description

July 16, 1929. $M|TH 1,721,261

CONDENSER Filed Oct. 12, 1926 2 Sheets-Sheet 1 WITNESSES:

v a. @1 W ATTORNEY J. H. SMITH July 16, 1929.

C ONDENS ER 1926 2 Sheets-She-t Filed Oct. 12

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INVENTOR WITNESSES:

ATTORNEY ?atented July 1, 1929.

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imam JOHN E. SMITH, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T WESTINGHOUSE ELECTRIC MANUFACTURING COMPANY,'A CORPORATION OF PENNSYLVANIA.

CONDENSER.

' Application filed October 12, 1926. Serial No. 141,221.

My inventionv relates to condensers for I steam power plants and it has for an object to provide'apparatus of this character wherein all of the tubes shall'be so disposed as to be highly active in transferring heat,

" thereby making'it possible to improve con- .denser design and performance.

With surface condensers, it is known that the outer tubes initially engaged by exhaust steam are more active from the standpoint of heat transfer than the more remote tubes. Therefore, it has occurred to me that the tubes located inside of the inner limit of good activity might be omitted and distributed outside, it being possible to do this with little increase in outside diameter of the tube nest and with little diminution in the activity of the prior outerzone of tubes. Apparently the reason for poor activity of the inner tubes of a condenser of this typevis that such tubes tend tojbecome surrounded with air and non-condensable vapors or gases, the latter serving to blanket or insulate the tubes and to resist 2 penetration of steam. It is one of the principal objects of my invention to improve the performance of a condenser by reducing or avoiding blanketing or insulation of tubes by air or vapor. This may be efiected by .suitably spacing the tubes and arranging them so that each tube may do its proper share of work, while at the same time, providing for short and direct vapor paths in order to minimize the drop in pressure in 5 the'condenser.

My invention may be embodied in condensers of various -ypes, as for example, in a condenser of the ;radial flow type. With condensers of the radial flow type, as here- 40 .tofore constructed, the tubes of the central core are frequently not fully efi'ective as heat transfer elements due to the general arrangement and to the operating conditions. in operation, condensation maybe efiected without deep penetration of steam into the tube nest and the tubes of the inner zone become surrounded with air and non-condensable gases which serve to blanket or insulate such tubes. Blanketing or insulation sets up resistance in the condenser. Under this condition, should the power plant load increase or should the temperature of the condenser cooling water increase, the blanketed or insulated tubes would offer resistance to the requiredfurthr penetration to effect condensation, resulting in less efficient performance. Blanketing or insulation of the inner tubes in this way, therefore, serves as'aclded resistance during normal operation and to produce poorer performance whenever the load I or the coolingtemperature increases.

In accordance with m invention, for example, taking .a standard design of radial flow condenser of a given size, I removethe' inner core of tubes which have heretofore defined an insulated or blanketed core under many conditions and the tubes so removed are distributed about those remaining. Inthis way, the same number of tubes may be used with only slightly increased outside diameter of the tube nest, and such.

a distribution of tubes may be had as to provide for a reduction in distance of and resistance to vapor travel. Also-the tube plates will not be increased in weight,-for it is possible to core them substantially and thereby reduce them in weight over standard practice.

As is well understood in the art, a radialfiow condenser is one wherein the nest of tubes is substantially surrounded by a steam belt and the air and non-condensable gas ofi-take is located within the nest. While my invention, in its broader aspects, may be applied to condensers of other types, nevertheless, in its-more specific aspects, my invention contemplates a condenser of the radial-flowtypaor a type similar thereto.

Accordingly, therefore, the drawings show a nest of tubes eccentrically' located with respect to the shell to provide an arcuate I steam space whose radial dimension diminishes away from the steam inlet and-theofi-take for air and non-condensable gases is located within the nest.

lhe application of 'my invention to. a radial flow condenser perhaps will be better understood'by reference to changes in a standard design. Taking a 40,000 sq. ,ft. condenser of the standard radial flow type having only a suficient core for-the air off: take, a central core of tubes of 64. in. in diameter may be removed and distributed about the outer tubes with an increase in outside diameter of only 7 in. -Distribution of tubes in this manner provides for a relatively larger number of tubes o into rum: ed1- ate and intimate contact with entering steam than is the case with the present standard arrangement, or, for that matter, than would be the case if more tubes are added to the present arrangement and the pitch thereof increased. A proportionately or larger total area between tubes is provided, and as above set forth, the distance of vapor travel and pressure drop through the condenser are obviously reduced whereas physical dimensions and distance ot'vapor travel as well as pressure drop are increased in the case of increased tube pitch arrangement.

A further object of my invention is, therefore, to reduce the distance of vapor travel in a condenser, to provide for better contact of entering steam with. the tubes, and to avoid or to minimize the insulation or blanksting of tubes by air and non-condensable gases by providing a relatively shallow band of condensing tubes.

These and other objects are eilected by my invention, as will be apparent from the following description and claims taken in connection with the accompanying drawipgs, forming a part of this application, in which: Fig. 1 is a longitudinal sectional view of a condenser embodying my invention;

Fig. 2 is an end elevation of the condenser shown in Fig. 1;

Referring first'to Fig. 7, in order that my invention may be more readily understood, It show a tube nest having a radial thickness (a) only suficient core-space being left to provide for the usual air ofitahe. For example, such an ofitake usually requires a space oi -approximately 15 in. in diameter.

My improved tube nest is in the term of an annular band of radial thickness t), the omitted inner core annulus of radial tll1Ckness (h) having. been added about the periphery of ((2), thereby increasing slightly the radius of the tube nest by an amount (0). As already pointed out, with 40,000 sq. ft. condenser, it was found-that acore amount ing to 64. in. diameter could be removed and the tubes thereoi distributedoutside with an increase in outside nest diameter of only in. Having shown the possibility of the reinoval oi core tubes and the distribution thereof about the periphery, possibly it may be well to emphasize again the reason for dolng this. TllfiOTQlHCtilly, trom the standagainst point of the resistance offered to and the distance of vapor travel, it would be better to v 'Bearing in mind that possibly better pertormance might be secured by an approach to this ideal condition and bearing in mind that the central core'of tubes of a standard condenser would frequently be jacketed or insulated by stagnant-air and-vapors, l have devised the present construction, which is advantageous tor'the following reasons:

1. The distance of vapor travel through the tube nest is diminished;

2. The permissible spacing and distribution of tubes is such that immediate and more intimate contact of steam therewith is assured and also the steam passes therethrough more readily and its residual velocity energy is more effective through the tubenest.

3.'Due to the larger number of tubes coming' into contact with the steam and to the decreased distance and resistance to travel of vapors through the tube nest, the cooling tubes act onthe average much more efficiently, I

Referring to Fig. 1, I show a condenser having a shell 10 provided with an inlet 11 for exhaust steam and with a hotwell 12 tor condensate. Tube plates 13 are arranged at the ends of the shell and water box members 14 and 15 are preferably se cured in place with respect to the shell ends, the tube plates 13 being clamped and held in place between the water box structures and the condenser ends as shown-in Fig. 1. The tube plates 13 support a nest oil tubes 16 in the usual way and intermediate tube supports 17 are preferably employed, these V supports being mounted in any suitable way with respect to the interior ofthe shell.

The nest of tubes 16 preferably takes the form of a shallow annular band such that a very substantial core 18 without tubesis provided. Eiince the tube nest 16 is in the form of an annular band, it is possible to core the tube plates 13 substantially as indicated at 19, thereby saving both in weight and in material in so far as the tube plates are concerned.

Any suitable air ofltake means may communicate with the core space. For example,

in Fig. 1, I show an airotltalre in the form of a tube or conduit 21 having lateral openings 22 communicating with. the space 18, this conduit being'connected to terminal portions 23 leading to any suitable air pump or ejector apparatus. lin order that the tube or conduit 21 may constitute a brace or strut for the tube plates 13, I show the ends thereof termihating in flanges 24-, which are secured in any suitable manner to the tube plates 13, the outlet members 23 preferably having flanged ends 25 which are secured to bers being secured. at their inner ends, to

the tube plates and, at their outer ends, to

I I the water box members and they are preferably so arranged as to provide for a fluidtight fit with respect to the outlet members 23..

It is is desired to arrange the condenser for two-pass operation, as shown in Figs; 1 and 2, diaphragms or plates 26'. are enclosed in the water box 14:, these diaphnagms or plates fitting the exterior of the drum 26 and providing a space' 28 communicating with the lowermost portio'n of the tube nest and having an inlet 29 for cooling water and a space 30 communicating with the uppermost portion of the tube nest and having an outlet 31. The water box member 15 defines a space 32 for connecting the. tube groups. Cooling water, therefore, enters the box space 28, passes through the lower group of tubes, then through the box space 32to the upper group of tubes and then to the outlet box space 30 and the outlet 31.

. In case it is desired to provide an arrangement, such as shown in Fig. 1, for singlepass operation, it is merely necessary, as shown in Fig. 3, to omit the dia hragms or plates 26' in association with the rum 26 and to provide one of the water box structures with an inlet and the other water box structure with an outlet.v

In some cases, it may be desirable to have the air oiftake provided with outlets emerg-v ing from the bottom of the condenser. Such an arrangement is shown in Fig. 4, wherein the air ofitake' member 34 is supported by hollow columns. 35 emerging from the bottom of the,condenser, these columns 35' being connected to any suitable air ejector or air removal apparatus. Also, in Fig. 4,-I

show. a deflector 35 arranged above the air ofltake member 34' for the purpose of minimizing the passage of condensate to the air offtake.

Owing to the fact that there is atendency" for most of the work to be done in a condenser at the upper portion thereof, in Fig.

, 5, I 'show an arrangement wherein the nest is provided with air-eccentric .core space 37, the %apparatus being otherwise similar to that already shown and described, that is, a com denser of this type may be either ,single or double-pass; and, if-made as a double-pass arrangement, obviously the diaphragms or division plates 38 would have to be so disposed in the water box 39 as to provide for a substantially equal division of tubes. In the drawings, I show a radial-flow type of condenser, that is, the tube nest has disposed thereabout an arcuate steam space 40 whose radial dimension decreases away from the steam inlet. The space 40 is-delittle more space than a air space is of decidedly larger minimum cross-sectional area than those heretofore in use. As already pointed out, it, has heretofore been the practice merely to make this central air core space large enough toaccommodate the an ofltake. For example,

. this air ofitake apparatus does not necessitate usually a space of more than 15 in. in di ameter and, in so far as I am aware, it has never exceeded more than 18 1n. 1n dlameter.

Inaccordance with the present invention, it

is not believed that any size of condenser would ever have an air core space less than 24in. in diameter, or a s ace whose minimum cross-sectional area 1s 450 sq. in. In

-lal e is also characteristic of my improved condenser that the ratio of inner periphery diameter oi the tube nest to the outer periphery diameter thereof is much larger than that heretofore employed. In accordance most cases, this air core space will be much with this invention, the air spacehas a much larger diameter, that is, the ratio of diameter of this space to the outside diameterof the tube nest is not lessthan one-third, for example, it maybe from 0ne-third to one-half, depending upon the size of the structure and the amount of condensing surface. The

ratio of one-half-could be exceeded so far as efliciency is concerned, but. such apparatus ratio of approximately one-third, or from one-third to one-half, a condenser may be made which is much more etficient than heretofore employed and which occupies but condenser ofstandard design.

If my improved condenser is compared with one of standard design, for the same size, it willbefound that the tube nest'is only slightly larger. in diameter and the core space diameter is relatively much larger.

Therefore, my invention difiers over priorart in that the air core area and diameter are substantially larger than those hereto would 1nvolve unwarranted cost. With a.

fore employed, with the result that, for the same size of condenser, the maximum diameter of the tube nest is only increased by a small amount and the performance ofthe condenser is 'greatl improved for the reason that the spaclng and distribution of tubes provides for shorter vapor paths through the tube nest endless resistance to vapor flow, with the result that the steam comes into immediate and intimate contact w1th the tubes and that the resistance to and the path of vapor flow through the tube nest are greatly diminished, thereb making it possible to utilize to the best a vantage the residual velocity possessed by steam in passing through the tube nest. By the use of my invention, I am able to improve decidedly the capacity of a condenser of a given size 5 for the reason that all of the tubes of the annular nest operate at a high rate of heat transfer. For example, assuming a standard 40,( )00 sq. ft. radial fiow condenser to be redesigned in accordance with my invention, it

' would have a much-larger capacity.

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 modi= fications, 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 specfically set forth in the appended claims.

'What I claim is:

1. A condenser comprising a shell encompassing a substantially hollow annular nest of tubes, and an offtakelwithin the nest and defining with the inner boundary tubes a 2 substantially annular core space for collecting air and non-condensable gases from the nest and for supplying collected air and noncondensable gases to the offtake.

2. A condenser comprising a shell having aninlet, a hollow nest of tubes within the shell and spaced therefrom so that a sub stantial portion of the outermost tubes of the nest define, with the shell, an arcuate steam delivery space in communication with said inlet, and an air ofi'take conduit extending longitudinally within and surrounded by the tube nest and spaced. from the inner boundary tubesso as to provide an intervening core space or chamber for collecting air and non-condensable gases from the nest and for supplying collected air and non-condensable gases to said ofi'take,

3. In a condenser, the combination of a shell having an inlet for exhaust steam and acondensate outlet, a substantially annular nest of tubes defining an inner core space for air and non-condensable gases, the diameter of said space being not less than one third of the outside diameter of the nest, the outer boundary tubes of said nest beingv 50 freely and un'interruptedly exposed to the entering steam and the inner boundary tubes defining said core space, an air ofi'take' communicating with said space, and means for circulating cooling water throu h the tubes.

4. In a condenser, the -comb1nation of ashell having an inlet for exhaust steam and a condensate outlet, a relatively shallow substantially annular band of tubes disposed within the shell'and defining therewith an arcuate steam delivery space, an air ofl'take arranged substantially centrally with respect to said nest and spaced from the inner boundary tubes of said nest to define an interveningspace for the reception of air and noncondensable gases from said nest, and means for circulating cooling medium through the tubes.

In testimony whereof, 'I have hereunto subscribed my name this 30th-day of September, 1926. ,7

' JOHN H. SMITH.

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