Circular crossflow cooling tower

March 29, 1966

3,243,166

R. R. OSENGA ET AL

CIRCULAR CROSSFLOW COOLING TOWER

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March 29, 1966

3,243,166

R. R. OSENGA ETAL

CIRCULAR CROSSFLOW COOLING TOWER

Filed Aug. 28, 1964

Sheets-Sheet 2

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United States Patent Office

3,243,166

Patented Mar. 29, 1966

3,243,166

CIRCULAR CROSSFLOW COOLING TOWER Raymond R. Osenga, Santa Rosa, and Alfred L. Fuller, Fullerton, Calif., assignors to The Fluor Corporation, Ltd., Los Angeles, Calif., a corporation of California

Filed Aug. 28,1964, Ser. No. 392,844

Claims. (CI. 261—23)

This invention relates generally to water cooling towers, and more particularly concerns so-called crossflow cooling towers wherein air passes crosswise of the path of dropping water and in cooling relation therewith.

At the present time cooling towers generally lack certain unusual advantages and features which it is a major object of the present invention to provide. Among these unusual advantages are the concentration of multiple fans in such a way as to greatly reduce the tower structure size and ground space required for a given water cooling capacity, a provision for accelerating the flow of air moving inwardly toward the fans in such manner as to reduce pressure drops, the maintenance of heat load availability despite shutdown of some tower fans, and the ready accessibility of the tower components including fan drives and water distributor means despite their incorporation in a very, large size tower.

These and other uncommon advantages may be considered to result from a novel crossflow type cooling tower having a vertical central axis, and including a chamber having an interior region located about the vertical axis, packing extending about the interior region for receiving water dropping downwardly to be contacted by cooling air passing across the packing generally inwardly toward the interior region, an air exhaust stack projecting above the top level of the chamber for receiving air from the interior region, and a series of fans spaced about the control axis in open vertical communication with the interior region and stack for displacing air to flow from the interior region upwardly in the stack so that the air velocity increases gradually as the air passes inwardly across the packing and into the interior region. Typically, the packing extends annularly continuously about the open interior region and concentrically with respect to a cylindrical air baffle projecting vertically inwardly of the open interior region, the result being that the inward air flow accelerates in moving toward the fan. Also, the baffle helps to effect upward turning of the air flow in the interior region and toward the undersides of the fans. A deck typically supports the fans outwardly of a vertical projection of the baffle and inwardly of a vertical projection of the stack. Further, upright interior partitions are circularly spaced in the interior region and extend inwardly toward the baffle in convergent relation to reduce pressure drops so as to promote operating efficiency.

It is another object of the invention to provide water distributing means extending annularly continuously about the axis of the above described tower and outwardly of a vertical projection of the enlarged diameter stack to supply dropping water for reception by the annular ring of packing. Further objects include the locating of the fans to extend in a horizontal plane sufficiently above the level of fan supporting decking, and also sufficiently outwardly of a vertical projection of the central baffle, that air flowing into the open interior region of the tower is turned to flow substantially vertically at the deck openings; the inclusion of individual venturi-shaped fan rings within the large outer stack; the forming of the stack as an elevated concrete cylinder supported by columns located inwardly of the packing, and the clustering of fan drivers inwardly of the fans and on decking to which access may be had through the cylindrical baffle and via a tunnel extending inwardly to the base of the baffle.

These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following detailed description of the drawings, in which:

FIG. 1 is an exterior elevation showing of one form of tower embodying the invention;

FIG. 2 is a plan view of the FIG. 1 tower;

FIG. 3 is a vertical sectional elevation taken on line 3—3 of FIG. 1;

FIG. 4 is an enlarged fragmentary elevational showing of the water distribution system; and

FIG. 5 is an enlarged fragmentary elevational showing of the detailed interior construction of the tower.

Referring in detail to the drawings, the cooling tower 15 10 is of crossflow type having a central vertical axis 11, and it includes a chamber 12 having an interior region 13 located about the axis 11. Region 13 may further be understood as located inwardly of an annular ring 14 of packing, and outwardly of an upright air baffle 15, 20 the ring of packing 14 and air baffle both extending concentrically about the axis 11. In this connection, it will be understood that the ring of packing is located to receive water dropping downwardly to be contacted by cooling air passing across the packing generally in25 wardly toward the. interior region 13, the baffle 15 functioning to promote an upward turning of the air flow within the interior region. Additionally, a series of fans 16 is spaced about the axis 11 in vertical communication with the interior region 13 of the tower as well as with 30 the interior 17 of a stack 18 for displacing air to flow from the interior region 13 upwardly in the stack, with the result that the air velocity increases during its travel inwardly across the packing and into the interior region 13 in such manner as to avoid sharp accelerations and 35 corresponding pressure drops during its coursing to the fans 16.

More specifically, the tower 12 typically comprises a relatively large concrete structure having a floor 19 sloping downwardly away from axis 11 toward an annular ⁴⁰ basin 20 that includes an annular trough 21, there being appropriate ring footings 22, 23, 24, 25 and 26 for the tower structure. The concrete stack 18 which encompasses the fans is carried by columns 27, best seen in FIG. 5, to be spaced apart about the axis 11 in order 45 to pass the cooling air inwardly into the interior region 13 below the fans 16.

The ring 14 of packing is carried on an annular concrete base 28 supported at 29 directly above the basin in order that water dropping through the packing may ⁵⁰ be collected in the basin and ultimately in the trough 21 for further use. The packing itself is of suitable crossflow type, vertically spaced decks or slats 30 being illustrated in FIGS. 3 and 4 as typical only. In this regard, it will be noted that near optimum utilization of space ⁵⁵ available for the packing is made by reason of its substantially continuous annular extent 'about the axis 11, thereby to obtain greater cooling capacity for a given size installation. At the same time, in accordance with the invention, provision is made to avoid abrupt changes ⁶⁰ in air flow and to force gradual inward acceleration of the air flow through the inner confines of the packing and into the interior region 13, for the purpose of avoiding sharp pressure drops.

A suitable ring or rings of drift eliminators 31 is lo65 cated at the inner side of the packing ring 14 and above the basin 20 to promote removal of such carry over or drift as does exist in the air stream leaving the packing and flowing toward the interior region 13. The drift eliminators may include horizontally extending baffles 32 70 angled to receive impingement of the air streams for separating out the moisture carried thereby. Finally, the ring

3,243,166 of packing is tapered inwardly in a downward direction in order that maximum utilization of packing surface may 'be achieved, in keeping with the tendency for dropping water particles to be displaced inwardly by the inwardly directed air streams.

Another aspect of the invention has to do with the provision of water distributing means extending annularly substantially continually about the axis 11, and also above the packing ring 14 outwardly of a vertical projection of the enlarged stack &gt;18, for supplying dropping water to the packing. Typically, the water distributing means includes annular decking 33 supported by radial beams 34 carried by circularly spaced tower columns 35. The decking carries water distributing nozzles or outlets 36 spaced above the packing ring 14, and to which water is supplied from an annular flume 37 extending about the stack vertical projection. In this regard, the annular extent of the decking 33 is typically subdivided into sections by the radially extending curbs 38, best seen in FIG. 2, so that each section 33a of decking between successive curbs 38 corresponds to one fan 16. For example, the air flow through a packing section directly beneath the decking section 33a is ultimately exhausted upwardly through the fans 16 corresponding to that decking section.

In accordance with a further aspect of the invention, during shutdown of a particular fan 16, such as for repairs, the water supply to the packing through which the air is drawn by that fan can be shut off. The particular way in which this may be done, as shown in the drawings, is made possible by provision of individual control gates generally indicated at 39 at the flume wall 40, there being one such gate for each section of decking between pairs of curbs 38. Typically, the control gate may include a gate member 41 movable vertically by a handwheel control actuator 42 to control an outlet in the flume wall 40 for passing water from within the flume to the decking nozzles, FIG. 4 best illustrating this construction. An annular over flow curb is provided at 43 outwardly of the bulk of the nozzles 36 to limit the depth of the water spread on the decking 33 and above the nozzles.

Reference to FIGS. 2 and 3 will show the provision of radially extending vertical partitions 44 inwardly of the packing ring 14 and outwardly of the cylindrical baffle 15, the partitions typically reaching from the flooring 19 upwardly to a deck 45 overlying the interior region 13 of the tower. Accordingly, the partitions form what may be characterized as sub-regions 13α which correspond to the decking portions 33a inasmuch as the partitions 44 are seen in FIG. 2 to lie in vertical radial planes defined by the curbs 38. The partitions 44 function by reason of their inwardly convergence to contribute toward acceleration of the air flow inwardly within the sub-regions 13α as the air flow courses toward the fans 16, thereby avoiding sharp accelerations and corresponding pressure drops. As indicated in FIG. 3, the partitions may be constructed of slats extending horizontally and radially. Furthermore, the cylindrical baffle 15 promotes upward turning of the air flow as indicated by the arrow 46 in FIG. 3 within each sub-region 13α. The fans extend in a horizontal plane spaced sufficiently above the level of the annular decking 33, and the fans are also spaced sufficiently outwardly of a vertical projection of the baffle 15, that air flowing into the sub-regions is turned to flow substantially vertically through the circularly spaced openings 47 in the deck 45, although some swirling motion is imparted to the flow as it approaches the fans. These air directing principles afforded by the novel construction of the tower promote high efficiency in terms of low pressure drops resulting from acceleration of the flow and also in terms of high cooling capacity.

It will be noted from FIGS. 1 and 3 that an access tunnel is provided at 48 to extend inwardly of the chamber for communicating between the exterior of the tower and the interior of the cylindrical air baffle 15. Within the latter, means is provided to gain vertical access to the deck 45, a suitable stairway 49 being typical of such means. Furthermore, the fan driving means is carried by the deck inwardly of the fans themselves in order that access may be had thereto at a generally central location corresponding to the location of vertical access to the deck 45. The latter contains an opening 50 through which equipment may be hoisted or lowered by a mechanism such as is indicated at 51, the opening 50 overlying the interior of the cylindrical baffle 15. The fan driving means may take the form of motors 52 grouped inwardly of a plurality of venturi-shaped fan rings 53 located within the stack 18, each ring having a vertical axis 54 and extending about one fan to promote upward air flow therethrough in response to fan rotation. The fan motors 52 typically drive the fans via shafting 55 and the right angle drive 56 located at the fan axis 54. A further advantageous result of the tower construction involving the use of multiple fans in the arrangement illustrated is found in that one or more fans may be shutdown to partially shutdown the tower while the heat load or cooling capacity is kept available through the distribution of water to be cooled to operating sections of the tower. In addition, the stack 18 in combination with the fans and venturi rings 53 creates an up draft within the stack which tends to affect equally the pressure conditions at the venturi ring outlets. As a result, if one fan is shutdown, air is still drawn vertically through the venturi ring by the up draft conditions in the stack 18 so that that section of the packing corresponding to the shutdown fan may still be operated by supply of water thereto to be cooled by the air induced to flow crosswise through the packing and upwardly through the fan ring into the stack.