US1941650A - Surface condenser - Google Patents

Description

Jan. 2, 1934. K. BAUMANN 1,941,650

SURFACE CONDENSER Filed Sept. 30. 1950 4 Sheets-Sheet 1 FaqJ INVENTOR KmL Bnumnnn.

BY arg P3 1% ATTORNEY Jan. 2, 1934.

K. BAUMANN SURFACE CONDENSER 4 Sheets-Sheet 2 Filed Sept. 30, 1930 a PM F OOOOLOOOO OOOOOOOOO INVENTOR Kma. Bnunnun.

BY 6L, 5, RAM/ ATTORNEY Jan. 2, 1934.. K BAUMANN 1,941,650

SURFACE CONDENSER Filed Sept, 50, 1950 4 Sheets-Sheet s INVENTOR Knm. Bnu MRHN.

BY CLIGIM ATTORNEY Jan. 2, 1934. K. BAUMANN SURFACE CONDENSER Filed Sept. 30, 1930 4 Sheets-Sheet 4 Faqdo.

ooooooo onoooo 9 O 0 0o INVENTOR KFIRL BRUMHHH.

ATTORNEY 1,941,650 "PATENT OFFICE SURFACE CONDENSER Karl Baumann, Urmston, England, assignor to Westinghouse Electric & Manufacturing Company, a corporation of Pennsylvania Application September 30, 1930,

Serial No.

485,352, and in Great Britain October 16,

- 8 Claims.

The invention relates to surface condensers and concerns more particularly condensers of the kindin which the cooling fluid flows in one general direction through the condenser through nests of tubes disposed transversely of the direction of flow of thevapour to be condensed. Such condensers are usually referred to as of the single-pass type, since the cooling fluid does not follow a sinuous or re-entrant path.

Condensers of this type have been found to suffer from the disadvantage that, since the cooling fluid is much cooler at the end where it enters the condenser than at the outlet end thereof, while the temperature of the vapour to be cooled is approximately the same over the whole length of the condenser, the quantity of vapour condensed per unit area of cooling surface is much greater at the inlet end than at the outlet end of the condenser. Consequently the vapour pressure falls more quickly at the end of the condenser where the cooling fluid enters than at the end where it leaves, and the flow of the vapour within the condenser and between the condenser and the air" extraction apparatus will be interfered with, and the efiicient utilization of the cooling surfaces seriously impaired unless special measures are taken to avoid this. Such measures heretofore proposed have, for example, involved the division of the condenser casing into separate vapour compartments with air extraction apparatus for each compartment or more or less complicated arrangements of nozzle devices in conjunction with a single air extraction apparatus designed to adjust the fall of pressure in the diflerent compartments so as to utilize efilciently the available cooling surface in each compartment.

The object of the present invention is to provide improvements whereby the disadvantages indicated above may be avoided in a simple manner, and according thereto, a condenser of the kind referred to is divided into compartments 'whereby the vapour to be condensed is caused to flow transversely of the cooling tubes in separate streams, and in order to obtain for all the streams over their entire length an equal pressure drop and also an equal degree of condensation, the several streams are arranged so that both the length of the vapour path followed and the cooling surface encountered therein increase as both the mean velocity of the vapour comprising the stream, and the mean temperature difiference between the vapour and the cooling surface decrease. The length of the stream or the densed vapour are withdrawn will thus be substantially greater in the case where the stream passes'in contact mainly with the portions of the cooling tubes near the cooling fluid outlet than in the case where the stream flows mainly in contact with the cooling tubes near the cooling fluid inlet since the velocity of flow will be substantially higher and consequently the drop in steam pressure and also the depth of condensation for a given length of path, greater in the latter case than in the former case; With a substantially equal degree of condensation in each stream the temperature and the'air concentration at the end of each stream will be substantially the same.

The invention may be carried out in various forms of construction, certain of which are hereinafter described by way of example with refer ence to the accompanying drawings.

These and other objects are effected by my invention, as will be apparent from the following description and claims taken in connection with the accompanying drawings, forming a part of this application, in which:

Figs. 1 to 5 represent diagrammatically longitudinal cross sections of various arrangements of the invention as applied to downward flow condensers';

Fig. 6 represents a transverse cross section which any of the condensers represented in Figs. 1 to 5 may have;

Fig. 7 represents diagrammatically an arrangement of the invention as applied to the condensers of the central flow type;

Figs. 8 and 9 show in longitudinal and transverse cross-section respectively a preferred 'constructional form of the invention; and,

Figs. 10 and 11 show in longitudinal and transverse cross section respectively a second preferred constructional arrangement of the invention.

Referring to Figs. 1 to 5, the vapour to be condensed, such as steam, enters the top 1 and fiows downwardly over a horizontal nest of cooling tubes 2 connecting inlet and outlet water boxes 3 and 4, respectively, at opposite ends of the condenser, the condensed water beingcollected at the bottom and drained off by a suitable drain 5, while the non-condensable gases are suitably removed at 6 from the lower region of the condenser. The condenser is divided into compartments by one or more vertical partitions or lagging plates 7 disposed transversely of the tube nest. Referring more specifically to Fig. 1, the compartment 8 adjacent the cooling water outlet communicates at the bottom with the lower portion 9 of the compartment 10 adjacent the cooling water inlet and an air withdrawal pipe 6 is disposed in a region of the compartment 10 intermediate the upper and lower portions there of. By this arrangement the path of the steam which flows downwardly through the compartment 10 is substantially shorter than the path oi the steam which flows downwardly through the compartment 8 and then upwardly through the lower portion 9 of the compartment 10, the length of the path. in each case being measured from the steam inlet 1 to the opening of the air withdrawal pipe 6, or the region where the air is extracted from the compartment 10. By a suitable choice of the position of the said opening of the air withdrawal pipe 6 the pressure drop and also the degree of condensation taking place in each of said paths may be. made substantially the same, and the cooling surface of the condenser is thus utilized in' a most efiective manner, while a single air extraction apparatus may be used for the withdrawal of the uncondensed vapour.

Generally, it is necessary. to divide the condenser into more than two compartments. Fig. 2 represents a condenser comprising three compartments wherein the two end compartments are arranged in communication as described above, while the intermediate compartment 11 is separate therefrom and has a separate air eduction aperture 12 disposed near the bottom thereof or otherwise in such a position as to render the pressure drop of the flow and the. degree of condensation in this compartment substantially the same as the pressure drop and the degree of condensation, respectively, of the other two streams-or flows. The same air extraction apparatus may serve to remove the air from both compartments.

The arrangement represented in Fig. 3 is virtually a combination of two arrangements similar to the one shcwn'in Fig. 1. The two central compartments 16 andl'l are connected together at the bottom and also to the common air extraction outlet 6, whilst the two outer compartments 8 and 10 are similar to the corresponding compartments 8 and 10 in Fig. 1 with the exception that a central portion 18 of the compartment 10 is traversed by the'combined stream from the compartments 16 and 17, in addition to the stream from the compartment v8.

Instead of arranging the intermediate compartment entirely separate from the other compartments as in the arrangement according to Fig. 2 it may be advantageous to place it in com-.

munication by a conduit 19 with a portion 9 of the compartment 10 adjacent the cooling water inlet 3, as shown in Fig. 4, in which case a common air extraction outlet 6 may serve for all the streams.

In the arrangement represented in Fig. 5,'certain or all of the individual streams of vapour, after flowing through the separate compartments 8, 10 and 11 may be permitted to join together in a compartment 21 before passing to the air extraction outlet 6. The final portion of the flow preferably takes place in contact with cooling tubes 20 immediately adjacent the cooling water inlet 3.

A greater number of compartments may be provided if desired, the compartments nearer to the outlet end ofthe condenser being placed in communication with appropriate. portions of the compartments nearer to the inlet end of the condenser and the several streams being combined as desired in accordance with the principles above set forth so that in all of the streams the pressure drop and also the degree of condensatiornis uniform and only a single air extraction device is rendered necessary.

It will be observed that withthe arrangement of streams described, the steam in the compartment 8, nearest the cooling water outlet is not fully condensed therein, and the .whole of the tube surface is therefore surrounded with steam containing only a very small proportion of air, the heat transmission in this compartment is, therefore, great with the result that the water is being heated, i. e. the tube surface utilized in that compartment throughout to the greatest possible extent.

In the case of downward flow condensers such as represented in Figs. 1-5, the tube nest may advantageously be somewhat wedge-shaped in cross section as shown in Fig. 6, being wide at the top and narrower at the bottom.

The invention is not limited to condensers of the downward flow type, but may readily be applied to the other types. Fig. 7 illustrates an application of the invention to a central flow type of condenser, in which the airwithdrawal zone 13 may comprise an annular space between two annular nests of tubes 14 and 15. The interior of the condenser may be partitioned in such a way that at the end of the condenser adjacent the cooling water inlet the steam or vapour flow is radially inwards through the outer nest of tubes to the air withdrawal zone, while at the other end of the condenser the flow is first radially inwards through both annular tube nests, then axially towards the cooling water inlet end of the condenser, and finally radially outwards through the inner tube nest to the air withdrawal zone 13..

Figs. 8 and 9 show the application of the invention to a single flow type condenser divided into five compartments. To simplify the figures nq tube plate stays have been shown and the openings in the tube plates are indicated diagrammatically. Steam enters the condenser at 1 and is split up into five streams by tube supportingplates 26, 27, 28 and 29, which divide the condenser into the five compartments 31, 32, 33, 34 and35. Air is extracted through an opening 6 communicating with the centre of the tube nest in compartment 31. is withdrawn from a well 5 at the bottom of the Condensate 12o condenser. In order to provide a path for -thevided to prevent the steam from entering this space at the side before it has traversed its appropriate surface in the tube nest. An additional baffle.30 is provided in compartment 31 covering the space corresponding to the opening 3'1 and extending a short distance into the tube nest. The vapour from each compartment is thus constrained to flow. as indicated by the arrows shown in Fig. 8, the steam path being longest and the surface passed over greatest for the steam entering compartment 35 where the, cooling water is warmest and therefore the rate of,

condensation lowest, while the length of path and surface encountered progressively decrease until they are least for the steam entering compartment 31 in which the steam is condensed by the cool incoming water most rapidly, its velocity past the tubes being therefore greatest.

Thus equal pressure drop from the steam inlet 1 to the air suction branch 6 is obtained for the steam entering the compartments and all parts of the cooling surface are utilized efficiently. Figs. 10 and 11 show a somewhat similar arrangement to the construction shown in Figs. 8 and 9. Each of the tube plates 26, 27, 28 and 29 is provided with one or more concentric openings, the vapour being constrained to flow over additional surface between the tube plates by flat plate bafiles 21, 22, 23 and 24 placed between the openings in the untubed space corresponding to these openings. In this particular construction, the vapour stream passing from one compartment to another automatically adjusts itself to that surface in the next compartment which is sufiicient to provide a pressure and degree of condensation equal to that existing at the end of the steam path in this compartment. This arrangement is independent of the number of compartments into which the condenser is divided. 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 changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon asare imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

l. A single-pass surface condenser having an inlet and having its condensing space divided into a plurality of compartments including a relatively cool and a relatively warm compartment, the condenser having a passage for conveying vapor from the warmer compartment to the cooler compartment on the side of the tube nest opposite the condenser inlet, and an outlet for gaseous medium disposed intermediate of the tube nest in the cooler compartment, whereby the vapor received by the warmer compartment passes through a longer path than the vapor received by the cooler compartment'directly from the condenser inlet.

2. A single-pass surface condenser having an inlet and having its condensing space divided into a plurality of compartments including a relcompartment, the tubes in the cooler compartment being arranged in inner and outer annular groups separated by an annular untubed space, the outer annular group receiving vapor on its outer side from the condenser inlet and the inner annular group receiving vapor on its inner side from the warmer compartment, and gaseous outlet means communicating with said annular untubed space.

inlet and outlet water boxes, tubes within the' shell extending between said tube sheets and conil necting the water boxes and partitions in said atively cool compartment and a relatively warm shell transverse to said tubes forming a plurality of condensing compartments of different heat absorbing capacities, said partitions each being formed to provide communication between said compartments, and a supplementary compartment in the compartment of greatest heat absorbing capacity for condensing substantially all the vapors flowing into said compartment of greatest heat absorbing capacity from the other compartments of the condenser.

5. A condenser comprising a shell, tube sheets, inlet and outlet water boxes, tubes within said shell extending between said tube sheets andconnecting the water boxes and partitions in said shell transverse to said tubes forming a plurality of condensing compartments of different heat absorbing capacities, each of said partitions being formed adjacent the terminus of the compartments to provide communication between said compartments and a partition in the compartment of greatest heat absorbing capacity disposed transverse to the condenser tubes passing therethrough and extending from the terminus of said compartment to a point intermediate the inlet and terminus of said compartment, said partition providing a supplementary compartmentadapted to condense substantially all the vapors flowing into said compartment of greatest heat absorbing capacity from the other compartments of the condenser.

6. A condenser comprising a; shell, tube sheets,

inlet and. outlet water boxes, tubes within said and spaced from said first mentioned partition .ends of the tube nest and dividing the latter, longitudinally, into a plurality of sections, and a common air outlet for at least two of the sections and located in that section which is nearer the cooling water inlet, said intermediate structural means and the air outlet being so constructed and arranged as to provide at least two separate and independent paths of travel for the steam and non-condensible gases, one of such paths extending'across a portion of the tubes in the section adjacent the cooling water inlet and the other of such paths extending across the tubes in another section and also across that portion of the tubes of the section adjacent the cooling water inlet not, traversed by said one path.

- 8. A condenser as claimed in claim 7 wherein the structural means also functions to support the tubes intermediate their ends.

KARL BAUMANN.

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