US3268217A

US3268217A - Cooling tower liquid interchange deck

Info

Publication number: US3268217A
Application number: US320380A
Authority: US
Inventors: Ernest E Goitein
Original assignee: FLUOR PRODUCTS CO
Current assignee: CUSTODIS-ECODYNE Inc; FLUOR PRODUCTS CO
Priority date: 1963-10-31
Filing date: 1963-10-31
Publication date: 1966-08-23
Anticipated expiration: 1983-08-23
Also published as: GB1068259A

Description

Aug. 23, 1966 E. E. Gom-:IN 3,268,217

COOLING TOWER LIQUID INTERCHANGE DECK Filed Oct. 3l. 1963 4 Sheets-Sheet 2 INVENTOR EPA/EST E GO/f//V BY JMJ fr. M

ATTORNEY x N FE FE FE EAN@ /Nm Mm i Aug. 23, 1966 E. E. Gom-:IN

COOLING TOWER LIQUID INTERCHANGE DECK 4 Sheets-Sheet 3 Filed Oct. 3l, 1963 lNvEN-roR Eem/57" f? 60/ nf//v ATTORNEY Allg. 23, 1966 E. E. GOITEIN COOLING TCWER LIQUID INTERCHANGE DECK 4 Sheets-Sheet 4 Filed 00T.. 5l, 1963 7o /A/fr WET eaL 75M@ D FLOW /l/R FLOW All? L INVENTOR Pn/5715. 60Hz/Af www uvm.

o m BY 70 /NLET W57' BULB TEMP. A/R/TLOW A/TFZOM ATTORNEY United States Patent O 3,268,217 CGLING TOWER LiQUiD INTERCHANGE DECK Ernest E. Goitein, Beimont, Calif., assignor, by mesne assignments, to Fluor Products Company, Santa Rosa, Calif., a corporation of California Filed Oct. 31, 1963, Ser. No. 320,380 7 Ciaims. (Cl. 261-110) This invention relates to improvements in the cross ctlotw type of cooling tower.

A cross iiow cooling tower is one in which the water to be cooled Hows by gravity in droplet form downwardly within the tower, while the cooling air flows through the Iwater essentially horizontally in a transverse direction relative to the ilow of water. Nozzles are provided for distributing the Water over a series of horizontal decks spaced vertically within the cooling tower, the decks comprising a number of elongated slats on which the water streams impinge.

Air draft may be produced by a fan acting to draw air from one side of the deck structure. In many installations, the fan is positioned in a central location encompassed by deck structure on all sides.

`It is apparent that as the air flows in the cooling tower horizontally from an air inlet side to the air exhaust side, it will become progressively warmer, by virtue of its contact with the Water which is warmer than the air. This in turn causes the water, particularly closer to the bottom of the tower, to be cooler on the air inlet side than on the air exhaust side. 11n a typical installation, at the bottom of the tower, the water temperature may be 74 on the air inlet side as compared to 91 on the air exhaust side.

This gradation results in a less effective transfer of heat, since, near the exhaust side, the temperature of the `air will approach the temperature of the water. As the temperatures of the water and air become closer, the rate of transfer of heat becomes correspondingly less.

Accordingly, it is an object of the present invention to provide means for improving the efliciency of cooling of the liquid ow in cross ow cooling towers.

In accordance with the invention, there is provided a cross iiow cooling tower -including a housing which has upwardly extending open walls deiining a heat exchange area, the heat exchange area having an air inlet side and an air exhaust side; a vertically extending deck structure within said area comprising a series of spaced apart horizontal decks arranged to d-isperse the water ow downwardly within the tower, means for flowing air between the decks from the inlet side to the exhaust side; means for introducing liquid at the top of the tower for downward gravity diow past the decks; and a liquid interchange deck intermediate upper and lower portions of the tower for transferring liquid from the relatively warm exhaust side to the cooler air inlet side of the tower and vice versa for more efficient cooling of the liquid; the interchange deck comprising means on the air inlet side of the tower and on the air exhaust side for collecting the downwardly ilowing liquid, means for conveying the collected liquid in separate streams from the air inlet side collecting means to the air exhaust side and vice versa, and means for distributing the liquid streams so conveyed for further downward flow past decks below said liquid interchange deck.

A principal advantage of the invention is that more efcient cooling of the liquid flow is obtained permitting a smaller heat exchange area for a given heat load, and thus a smaller sized cooling torwer.

The advantages of the invention should become more apparent on consideration of the enclosed drawings.

FIGUR-E 1 is a view of the cooling tower in side eleva- ICC tion with the left hand portion in vertical cross section in accordance with the invention.

FIGURE 2 is an enlarged cross section of a portion of the cooling tower shown in FIGURE l.

FIGURE 3 is a plan view of a portion of an interchange deck in detail embodying the concepts of the 1nvent1on.

FIGURE 4 is a vertical section view taken on line 4-4 of FIGURE 3.

FIGURE 5 is a similar section View as FIGURE 4 taken on line 5-5 of FIGURE 3.

FIGURES 6 and 7 are graphs comparing the advantages achieved in accordance with the invention over conventional cooling tower structures.

The tower includes -a housing which may be circular, square, or rectangular, designated by the numeral 12, having on two opposite walls a casing 13, the remaining opposite sides 14 being open for the passage of air into the tower. The housing includes upwardly extending frame support members 15 and horizontal frame cross members 16. The cooling tower illustrated is shaped so as to have a central vertically extending inner passageway 1=8 leading to a fan stack 20 located at the upper end of the tower. With reference to the section shown in FIG- URE 1, a fan 21 within the stack 20 draws air through -or past open wall structure 22 on the air inlet side 24 of the tower, horizontally through the tower, and past drift eliminators 26 on the exhaust interior side 28 adjacent passageway 18. 'Iihe wall structures on the inlet and

exhaust sides

24 and 28 of the cooling tower are slanted rto compensate for movement of the downwardly ilowing water in the direciton of the air ow. The drift eliminators 26 are arranged to prevent lthe passage of water, entrained in the air ow, into the passageway 1S and stack 20.

A typical iill within the cooling tower housing comprises decks 30 consisting of horizontal support members 32 aligned with the direction of air flow, supporting elongated slats 34 disposed in a direction substantially transverse to the air flow. The till occupies substantially the entire heat exchange area of the cooling tower, but the slats are spaced apart and also staggered so that water flowing by gravity past the decks and from -one series of slats onto the slats of the next lower deck is dispersed in the air ow.

At the upper end of the cooling tower, there is provided a Water distribution basin 36 in which several inches of water are contained. The distribution basin is provided with a series of nozzles (not shown), which may be spaced about a foot to two feet apart, so that water flows at a controlled and predetermined rate from the basin. Beneath the basin are disposed a number of diffusion decks 40 so that the water flows onto the ditiusion decks, and from the decks downwardly uniformly onto the spaced slats 34.

In accordance with the invention, an interchange deck 42 is provided about halfway down the tower designed to transfer the water falling down the exhaust side 28 of the tower to the inlet side 24 of the tower, and the water on the inlet side 24 in the opposite direction.

FIGS. 2, 3, and 4 and 5 illustrate the deck 42 in detail, in accordance with one embodiment of the invention. The deck 42 is comprised of a horizontal plate 44 eX- tending across the cooling tower water-How area, the plate having upwardly extending end and side walls 45 defining a large horizontal catch basin. Supported on the plate 44 are a plurality of elongated housings 46 aligned generally with the direction of the air flow. The housings are made up of opposite side walls 48 and a roof 50, and are spaced apart so as to define a series of approximately parallel open troughs 54 between and alternating with the encl-osed channels. The housings also abut Iat one end against the deck end walls 45 adjacent air inlet and

exhaust sides

24 and 28. The -dimensions of the housings are such that the channels and troughs have Iapproximately the same width.

In the present embodiment, each housing extends in the direction of air flow only half of the distance across the cooling tower fill area, so as to define one series of channels and troughs adjacent the air inlet side 24 of the tower and a second series adjacent the air exhaust side 28. The housings of the two sides are staggered relative to each other, so that a channel 52 of one side abuts a trough 54 of the other side. The roofs 50 of each of the housings are slanted `so that water impinging on the roofs flows into the intermediate troughs 54. Within the housings, nozzles 56 are disposed in the deck plate for the flow of water through the plate.

The interchange deck operates in the following manner. Water flowing downwardly onto a roof 50 or into a trough 54 is collected in the trough. This collection of water flows longitudinally along the trough into an abutting closed channel of the abutting section for dispersion through the nozzles disposed within the channel. Thus the water collected on the air inlet side is transferred to the air exhaust side, and water on the exhaust side is transferred in the opposite direction to the air inlet side.

The nozzles used in the -deck at the top of the tower are generally sized to effect a desired distribution and flow onto the cooling tower slats. As a feature of the invention, the nozzles in the interchange decks are generally larger but spaced further apart to achieve the same flow, but being larger clogging is more or less prevented. The reason for this is that the nozzles in the upper deck are readily accessible for cleaning purposes, but the nozzles in the interchange deck are less accessible.

Referring to FIG. 1, it is apparent that the interchange deck occupies only a very .small space within the cooling tower. It will be shown that a substantial improvement in heat transfer results, far -outweighing the small loss of heat exchange area. As a further feature of the invention, the interchange deck effects a redistribution of the liquid in the cooling tower for more effective cooling.

FIGS. 6 and 7 illustrate the advantages achieved in accordance'with the invention. In FIG. 6, the temperature distribution of water in a typical cross flow tower is illustrated. The point A represents the upper edge on the air inlet side of a tower, whereas the point B represents the lower edge on the air inlet side of a tower. The air and water flow in the directions indicated. As the air flows through the cooling tower it becomes progressively warmer, and the liquid, at the same level in the tower, also is warmer, or less cooled nearer the exhaust side. Thus the constant temperature lines assume the slopes shown. For instance, 94 temperature water on the air exhaust side will be found much further down in the tower than 94 temperature water on the inlet side. At the bottom of the tower the temperature gradient of the water extends from 74 at the air inlet side to a water temperature of about 91 at the air exhaust side, for what is called a weighted cold water temperature of about 85.1.

In FIG. 7, there is an intermediate exchange of cold water for warmer water in accordance with the invention. The warmer water which has a weighted temperature of 93.2 is transferred to the cold air side. The colder water on the inlet side having a weighted ternperature of about 87.1 is transferred to the air exhaust and warmer side. With the greater temperature differential between the water and air, particularly on the air inlet side, in the lower part of the cooling tower, a more effective transfer of heat is achieved. Thus, at the bottom of the tower, on the cold water -inlet side, the weighted cold water temperature is dropped to 80.6, and on the hot water exhaust side, to 85.3, for an average cold water temperature of 83.0. This is to be compared with the temperature of 85.1 in a conventional unit.

Modifications in the invention will be apparent to those skilled in the art. For instance, depending upon the size of the unit, a number of interchange decks could be disposed at vertically spaced intervals within the cooling tower. In addition, the invention is useful for all cross flow cooling towers, and its application is not limited to the particular type of cooling tower illustrated.

It also may be found advantageous to use a lar-ger number of smaller interchange decks to reduce the temperature gradients across the cooling tower. Also, it may be found advantageous to use water catch basins for the intechange deck made in the form of individual trays or drawers mounted so that they can be readily lremoved for cleaning as one removes a drawer from a chest. The redistributing portion (plate 44 with nozzles 56) of the deck can also be made separate from the catch basin arrangement and individually removable for cleaning. Other variations will he within the scope and spirit of the invention as defined in the following claims.

What is claimed is:

1. A cross flow cooling tower comprising a upper reach and a lower reach, a housing having means for flowing air approximately horizontally thorugh the housing defining an air inlet side and an air exhaust side for the housing,

means for flowing a liquid downwardly through the housing by gravity in cross flow relationship relative to the flow of air,

a fill within said housing upper and lower reaches providing a wetted surface for direct contact of air and the liquid,

a horizontal interchange deck between said upper and lower reaches, said interchange deck comprising a plurality of alternating channels having slanted roofs and troughs on the air inlet side and on the air exhaust side for collecting the liquid flowing downwardly from said upper reach, means comprising said channels and troughs in abutting staggered relation for conveying the collected liquid in separated streams from the air inlet side to the air exhaust side and vice versa,

and means for distributing the liquid streams so conveyed to said housing lower reach.

2. A cross flow cooling tower comprising an upwardly extending housing having an upper reach and a lower reach,

means for flowing air approximately horizontally through the housing defining an air inlet side and an air exhaust side for the housing,

a horizontal interchange deck between said upper and lower reaches, said interchange deck compirsing a first section adjacent the air inlet side, a second seetion adjacent the exhaust side, means defining in each of said sections a plurality of elongated parallel troughs and channels, the troughs and channels alternating with each other, said channels being closed so that liquid flowing downwardly from the housing upper reach on to the section is collected only in the troughs, the channels and troughs of said sections being in staggered abutting relation so that liquid collected in the troughs of the first section flows in a plurality of streams to the channels of the second section and vice versa, the oppositely flowing streams being maintained separate,

and means in said channels for distributing liquid from the channels to the lower reach of the cooling tower.

3. A cross flow cooling tower according to claim 2 wherein said interchange deck sections are contiguous, the troughs of the rst section being aligned with and abutting the channels of the second section, and vice versa.

4. A cross flow cooling tower according to claim 3 wherein the outer surfaces of the channels exposed to tlow of liquid from the upper reach are slanted to divert the flow to adjacent troughs.

5. A cross flow cooling tower according to claim 3 wherein said troughs and channels are aligned approximately with the ow 4of air throu-gh the cooling tower.

6. A cross flow cooling tower according to claim 5 wherein said upper and lower reaches have approximately the same vertical dimension, said sections having approximately the same dimension in the direction of air ow.

7. A cross iiow cooling tower comprising a housing having an upper reach and a lower reach of approximately the same vertical dimension,

means for ilowing air approximately horizontally through the housing dening for the housing an air inlet side and an air exhaust side,

means for llowing a liquid downwardly through the housing by gravity in cross flow relationship relative to the flow lof air,

a ll within said housing upper and lower reaches providing a wetted surface for direct contact of air and the liquid, said ll including a plurality of splash decks arranged `so that the liquid cascades through the tower,

a horizontal interchange deck between said upper and lower reaches, said interchange deck comprising a first section adjacent the air inlet side, a second section adjacent the air exhaust side, said sections in the direction of air flow having approximately the same dimension and being contiguous,

means dening in each of said sections a plurality of elongated Iparallel adjacent troughs and channels, the troughs and channels being aligned with the direction of air ow and alternating with each other, the channels further having walls and being covered by a rooi:` and the troughs being open so that liquid cascading downwardly from the upper reach is diverted from the channel by the roof thereof and is collected only in the troughs,

the troughs lof the first section being aligned with and abutting the channels of the second section and vice versa, so that liquid collected in the troughs of one section ilows 4in a plurality of streams to the channels of the other section, the oppositely llowing streams being maintained separate,

and means in the channels for distributing the liquid in the channels to the lower reach of the cooling tower on the air inlet and air exhaust sides respectively.

Reierences Cited by the Examiner UNITED STATES PATENTS 1,334,515 3/1920 Braun 261-110 2,247,514 7/1941 Mart. 2,497,389 2/1950 Ahrens 261-111 2,512,271 6/1950 Green 261-111 2,776,121 1/ 1957 Fordyce. 3,115,534 12/1963 Bottner.

HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner.

Claims

1. A CROSS FLOW COOLING TOWER COMPRISING A UPPER REACH AND A LOWER REACH, A HOUSING HAVING MEANS FOR FLOWING AIR APPROXIMATELY HORIZONTALLY THROUGH THE HOUSING DEFINING AN AIR INLET SIDE AND AN AIR EXHAUST SIDE FOR THE HOUSING, MEANS FOR FLOWING A LIQUID DOWNWARDLY THROUGH THE HOUSING BY GRAVITY IN CROSS FLOW RELATIONSHIP RELATIVE TO THE FLOW OF AIR, A FILL WITHIN SAID HOUSING UPPER AND LOWER REACHES PROVIDING A WETTED SURFACE FOR DIRECT CONTACT OF AIR AND THE LIQUID, A HORIZONTAL INTERCHANGE DECK BETWEEN SAID UPPER AND LOWER REACHES, SAID INTERCHANGE DECK COMPRISING A PLURALITY OF ALTERNATING CHANNELS HAVING SLANTED ROOFS AND TROUGHS ON THE AIR INLET SIDE AND ON THE AIR EXHAUST SIDE FOR COLLECTING THE LIQUID FLOWING DOWNWARDLY FROM SAID UPPER REACH MEANS COMPRISING