US3648990A

US3648990A - Cooling tower

Info

Publication number: US3648990A
Application number: US773531A
Authority: US
Inventors: Robert J Stoker; James E Hanley
Original assignee: Individual
Current assignee: Citibank NA
Priority date: 1968-11-05
Filing date: 1968-11-05
Publication date: 1972-03-14
Anticipated expiration: 1989-03-14

Abstract

A cooling tower construction particularly useful in natural draft cooling towers. The fill assembly is conventional and may be arranged for either cross flow or counterflow. A plurality of similarly shaped prefabricated modular units are secured to each other to form the stack. The modular units are sufficiently strong to support the stack. The sides of the stack are closed by corrugated sheets of plastic or other materials.

Description

United States Patent Stoker et a1.

[54] COOLING TOWER [72] Inventors: Robert J. Stoker, 413 March Boulevard, Phillipsburg, NJ. 08865; James E. Hanley, II, 2122 Westgate Drive, Bethlehem, Pa.

[22] Filed: Nov. 5, 1968 [21] Appl. No.: 773,531

[52] U.S.Cl ..26l/109,261/11l,52/245, 261/DIG. ll

[51] Int. Cl. ..B01f3/04 [58] Field of Search ..52/244, 245;

' 261/108-112, DlG. ll

[56] References Cited UNITED STATES PATENTS 795,332 7/1905 Broome ..52/245X 5] Mar. 14, 1972 Bowman ..261/1 10 X 3,226,894 1/1966 Burchardt et a1. .....26/ 108 X 3,300,942 1/1967 Horstman ..261/ 108 X 3,498,590 3/1970 Furlong ..26l/DlG. 11

Primary ExaminerTim R. Miles Assistant Examiner-Steven H. Markowitz AttorneyCarl R. l-lorten, David W. Tibbott and Frank H. Thomson [57] ABSTRACT A cooling tower construction particularly useful in natural draft cooling towers. The fill assembly is conventional and may be arranged for either cross flow or counterflow. A plurality of similarly shaped prefabricated modular units are secured to each other to form the stack. The modular units are sufiiciently strong to support the stack. The sides of the stack are closed by corrugated sheets of plastic or other materials.

6 Claims, 5 Drawing Figures PATENTEDMAR 14 I972 SHEET 1 [IF 2 INVENTORS ROBERT J. STOK'ER JAMES E. HA NLEYIII FAYENFEWR 14 1972 SHEU 2 [IF 2 INVENTOIIQS ROBERT J.STOKER \J/wuas E.HANLEY1I BY g; 4M

ATTORNEY COOLING TOWER BACKGROUND OF THE INVENTION This invention relates to cooling towers and more particularly to large natural draft cooling towers which employ a high stack to induce flow of air through the fill assembly to thereby cool the water.

Cooling towers employ the principle of air flowing through falling water to evaporate some of the water and thereby cool the water. The air fiow may be induced by a mechanical fan at either the inlet or the outlet of the cooling tower or by a chimney or stack which develops a natural flow of air. In order to be high enough to induce a sufficient volume of air flow to cool the water the desired amount, the stack of a natural draft cooling tower must often reach heights of 300 feet and more. With such heights, wind and other uncontrollable factors such as earthquakes will severly affect the tower. Great strength is required to withstand these factors.

Early natural draft cooling towers were constructed of wood and other materials in the form of a straight cone. It was found that the tower could not be built high enough to develop enough air flow to adequately cool the water. In order to achieve the height necessary to develop sufficient air flow, many present day natural draft cooling towers are constructed of reinforced concrete in the form of a hyperbolic shell as shown in US. Pat. Nos. 3,322,409 and 3,360,906. The double curvature provided by the hyperbolic shape enables the wall thickness to be reduced to a point where a concrete structure becomes economical. Theoretically, the hyperbolic shape provides an additional advantage over other shapes by conforming to the air flow pattern in the stack.

Reinforced concrete construction presents several disadvantages. Construction costs are high. Forms must be constructed, the concrete poured and the forms removed. The curved shape of the structure requires the construction of complex forms. The cost of maintaining a concrete structure of such height can be high. Spalling of the concrete often occurs and is not easily repaired. Once the concrete tower is completed, the height of the tower cannot be increased if it is determined that an increase in tower height is necessary.

It has been found that the hyperbolic shape is not necessary to induce the air flow required in a natural draft cooling tower. A generally cylindrical shape will provide essentially the same amount of air flow. Construction costs will be reduced since a cylindrical shape is generally easier to construct than a hyperbolic shape. A concrete structure is not strong enough to permit economical construction of the tower in the form of a cylinder.

If a steel construction could be employed, maintenance costs could be reduced. A steel construction will provide the strength necessary to permit a generally cylindrical shape. Construction costs will be reduced because it will not be necessary to build complex forms. Prior methods of construction have the disadvantage that most of the work must be done at great heights. With prior methods of construction, it is necessary to do most of the construction at the tower site. Virtually no ground level construction can be done.

SUMMARY It is therefore the principle object of this invention to provide a cooling tower construction which will result in a substantial reduction in the cost of construction.

It is another object of this invention to provide a stack for a natural draft cooling tower which has greater resistance to wind forces than prior cooling towers.

It is a further object of this invention to provide a cooling tower stack construction which will permit a maximum amount of ground level construction.

It is a still further object of this invention to provide a cooling tower stack. construction which will permit the height of the tower to be increased if it is found that a greater air flow is desired and an increase in height will induce such greater air flow.

In general, the foregoing and other objects will be carried out by providing a cooling tower including a fill assembly through which water to be cooled is adapted to gravitate and air is adapted to flow and a hollow upright stack having upwardly extending closed sidewalls, an open top defining an outlet for the stack and an opening near itslower extremity communicating with said fill assembly defining an inlet for said stack said upwardly extending closed sidewalls comprising: a plurality of prefabricated substantially similarly shaped modular units secured to each other in side by side relationship; means for securing each modular unit to itsadjacent modular units and sheet means for covering said modular units for closing said sidewalls.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view of thercool ing tower of the present invention with parts broken away and certain parts shown schematically for purposes of clarity,

FIG. 2 is a top plan view of the towerof the present invention;

FIG. 3 is a perspective view of a portion of the tower of the present invention-and illustrating the modular unit construction of the stack;

FIG. 4 is a fragmentary view of a portionof the present invention; and

FIG. 5 is a fragmentary view of another portion of the present invention.

DESCRIPTION OF THE PREFERRED. EMBODIMENT The present invention will be described in connection with a natural draft cooling tower of the crossflow type but it is intended that the invention is equallyapplicableto a counterflow arrangement.

Referring to FIGS. 1 and 2, the cooling tower of the present invention includes a stack of generally tubular construction and generally indicated at l. The stackis provided with an open top 2 which defines an outlet for the stack. The bottom or lower extremity of the stack is open as at 3 to define an inlet for the stack. The stack is provided with upwardly extending closed sidewalls 4. Support legs 5 are connected at one end to the sidewalls 4 and at their other end to concrete support members 6. The concrete members 6 maybe integral with a concrete ring 7 of sufficient depth and weight to support the stack 1.

A fill assembly, of any well known type, surrounds and is in communication with the open base 3 of the stack and is generally indicated at. 10. The fill assembly may include a supply pipe 11 which extends around the till assembly 10 for supplying water to becooled. From the supply pipe 11 a distribution pipe 12. extends upwardly to the top of the'fill assembly l0 and distributes water to be cooled to the packing 13. The packing 13 may be anywell known type such as a splash bar or a tray arrangement. The fill assembly is provided with louvers 14 which direct air flow across the packing l3. Drift eliminators 15 are provided to direct the flow of air towards the inlet 3 and stack 1. Heavy outside air enters the cooling tower through louvers 14, passes through the packing 13 which water is falling and into the stack 1 through inlet 3. The lighter saturated air in the tower is displaced up and out the outlet 2. A well 16 collects the cooled water and suitable means may be provided for conducting" the cooled water out of the well 16. A roof 17 is provided for covering the fill assembly 10. If desired, well 16 may be defined by the entire base portion of the cooling tower.

By the present invention, a stack has been provided which is constructed of steel and permits ground level construction of the componentsof the stack. Prior methods of construction of large natural draft cooling towers required that most work be done above the ground and hence construction costs were high. By the present invention the upwardly extending closed Inlansidewalls 4 are constructed of a plurality of prefabricated similarly shaped modular units. In the present embodiment the modular units are constructed of an open frame work of steel. When the tower or stack is completed, the upwardly extending walls 4 are closed by a sheet material which may be corrugated for purposes of strength. For simplicity, some of the modular units have been shown schematically in FIG. 1.

The modular unit is generally indicated at and can best be seen by reference to FIG. 3. In FIG. 3, more than one modular unit is shown so that the coupling of one modular unit to its adjacent modular units can be seen. The various modular units have been designated as 20, 20a and 20b. An important consideration in constructing the modular units is that they be sufficiently strong in compression, tension and shear to support themselves and the great weight of the tower.

Each modular unit 20 includes a horizontal or first member generally indicated at and a vertical or second member generally indicated at 30. The horizontal member is preferably, although not necessarily, constructed of a pair of

structural members

26 and 27 and interconnecting structural members 28. The structural member 27 which is on the outside of the tower l is slightly tapered inwardly toward the structural member 26. The taper extends from the intersection of the horizontal member 25 and vertical member 30 toward the adjacent modular unit 20a. This taper permits two modular units 20 and 20a to be connected to each other at an angle so that the cylindrical construction of the tower can be formed.

The vertical member 30 is constructed of a pair of parallel

structural members

31 and 32 which are interconnected by bracing members 33.

A first cross member 36 in the form of an I-I-beam extends at an angle downwardly from the intersection of the horizontal member 25 and the vertical member 30. When the modular units are secured to each other to form the stack, the cross member 36 will be secured to the intersection of the vertical and horizontal members of an adjacent modular unit. A second structural member 35 in the form of an H-beam extends from the outer extremity of the horizontal member 25 to the outer extremity of the vertical member 30. The cross member 36 is formed of two pieces secured to each other and the cross member 35 by a plate 37.

The horizontal and

vertical members

25 and 30 respectively are joined to each other by means of

plates

40 and 41. The

plates

40 and 41 which are on the inside and outside respectively of the tower extend above and beyond the horizontal member 25 and vertical member 30. Adjacent modular units are connected to each other by

plates

40 and 41 and suitable fasteners as is clearly shown in FIG. 3. In addition to the

plates

40 and 41, connecting plates 42 and 43 may be provided for securing a vertical member of one modular unit to a vertical member to an adjacent modular unit.

Each of the modular units 20 may be constructed at ground level such as in the factory and shipped in their final form to the construction site. A plurality of modular units may be coupled together at ground level to form a section of the stack. The completed section is then raised into place by means of a crane or helicopter.

When completed, the tower takes the form of a plurality of rings 21 each constructed of a plurality of modular units joined together in side by side relationship. The rings are stacked on each other so that the horizontal member 25 of the modular units 20 of one ring are in the same plane and the vertical members 30 of the modular units are coaxial. This construction is apparent from FIG. 1. If necessary, the height of the tower can be increased by adding additional rings 21.

In order to increase the strength of the tower and to provide a better air flow path, upwardly extending sidewalls 4 are tapered outwardly near the bottom of the tower. The ring 21a at the juncture of the cylindrical and tapered portions of the stack includes vertical members in which the outer structural member 32 is longer than the inner structural member 31 of the vertical member 30 as shown in FIG. 5. This insures that the taper will be properly constructed.

As the circumference of the tower increases, it is necessary to increase the length of the modular units 20 by increasing the length of member 25 and cross members 35 and 36. The height of the modular units will remain constant throughout the stack. Although the modular unit is longer, it is substantially similarly shaped to all of the modular units in the stack and construction is basically the same. For each ring 21 in the tapered section of the stack the horizontal member 25 will be a constant length.

Where the tower joins the support legs 5 the vertical member 30 must be inwardly tapered so that the modular unit meets the legs 5. This taper is clearly shown in FIG. 4 where the

structural members

31 and 32 are inwardly tapered to meet a ring beam 45 which is in turn joined to the support legs 5. Despite this taper, the modular units on the bottom ring of the tower are substantially the same as all the other units of the tower.

When the stack is completed by having all the modular units in place, or as construction of the stack proceeds, a sheet material such as corrugated plastic 50 is secured to the inside of the stack to close the sidewalls of the stack. The sheet 50 is of strength and is secured to the stack in such a manner that in a high wind, it will break away from the tower before the tower fails. When the sheet 50 breaks away, wind will freely blow through the tower. The inside is covered to permit free access to the structural members of the modular units 20 for purposes of maintenance. It is not essential to employ corrugated sheet but it has been found that a thinner material may be used.

It is apparent from the foregoing description that the objects of this invention have been carried out. The modular construction reduces costs. It is believed that a more stable and safer structure is provided.

By the present construction, the modular units can be ground assembled thereby reducing construction costs by permitting the use of mass production techniques. Because the stack is so large and so many modular units are required to complete a ring 21, even the modular units which form the tapered sections of the stack may be mass produced. The modular units are of sufficient strength to permit the tower to support itself. The stack is thus able to withstand severe weather conditions such as wind which will be encountered by the tower. If it is deemed necessary to increase the height of the tower in order to increase the volume of air flow through the fill assembly, additional rings 21 may be added to the tower.

We claim:

1. In a cooling tower including a fill assembly through which water to be cooled is adapted to gravitate and air is adapted to flow and a hollow, upright stack having upwardly extending, closed sidewalls, an open top defining an outlet for the stack and an opening near its lower extremity communicating with said fill assembly defining an inlet for said stack, said upwardly extending sidewalls comprising:

a plurality of prefabricated similarly shaped modular units secured to each other in side by side relationship and having a horizontal member;

a vertical member having one extremity secured to and extending from one extremity of said horizontal member;

a first cross member extending angularly from the intersection of said horizontal member and said vertical member toward the intersection of the horizontal member and vertical member of an adjacent modular unit;

a second cross member extending between the other extremity of said horizontal member and the other extremity of said vertical member;

means for securing each modular unit to its adjacent modular units; and

sheet means for covering said modular units for closing said sidewalls.

2. In the cooling tower of claim 1, said modular units being dimensioned to increase in length as the circumference of said stack increases.

Iliumnae:

3. ln the cooling tower of claim 2, said means for securing said modular sections to its adjacent units including plate means and fastener means.

4. ln the cooling tower of claim 3, said sheet means being corrugated.

5. In the cooling tower of claim 4, said sheet means being secured to the inside of said stack.

6. A cooling tower comprising:

a fill assembly through which water to be cooled and air for cooling said water are adapted to flow;

a hollow, upright stack having closed sides extending upwardly from said fill assembly, an open top defining an air outlet for the stack and an opening near its bottom defining an air inlet communicating with said fill assembly so that air for cooling said water will flow through said fill assembly toward said outlet;

means for securing said stack to the earth;

said closed sides being constructed from a plurality of stacked rings; and

means for securing each ring to its adjacent rings;

each of said rings comprising:

a plurality of prefabricated substantially similarly shaped modular unit secured to each other in side by side relationship; and means for securing each modular unit to its adjacent modular unit;

each of said modular units further comprising:

a horizontal member wherein the horizontal member of each of said modular units includes first and second structural members taperingly spaced apart by a plurality of shorter members so that a generally circular ring is formed when the modular units are secured to each other;

a vertical member having one extremity secured to and extending from one extremity of said horizontal member.

a first cross member extending angularly from the interesection of said horizontal member and said vertical member toward the intersection of the horizontal member and vertical member of an adjacent modular unit; and

a second cross member extending between the other extremity of said horizontal member and the other extremity of said vertical member.

Claims

1. In a cooling tower including a fill assembly through which water to be cooled is adapted to gravitate and aiR is adapted to flow and a hollow, upright stack having upwardly extending, closed sidewalls, an open top defining an outlet for the stack and an opening near its lower extremity communicating with said fill assembly defining an inlet for said stack, said upwardly extending sidewalls comprising: a plurality of prefabricated similarly shaped modular units secured to each other in side by side relationship and having a horizontal member; a vertical member having one extremity secured to and extending from one extremity of said horizontal member; a first cross member extending angularly from the intersection of said horizontal member and said vertical member toward the intersection of the horizontal member and vertical member of an adjacent modular unit; a second cross member extending between the other extremity of said horizontal member and the other extremity of said vertical member; means for securing each modular unit to its adjacent modular units; and sheet means for covering said modular units for closing said sidewalls.

3. In the cooling tower of claim 2, said means for securing said modular sections to its adjacent units including plate means and fastener means.

4. In the cooling tower of claim 3, said sheet means being corrugated.

6. A cooling tower comprising: a fill assembly through which water to be cooled and air for cooling said water are adapted to flow; a hollow, upright stack having closed sides extending upwardly from said fill assembly, an open top defining an air outlet for the stack and an opening near its bottom defining an air inlet communicating with said fill assembly so that air for cooling said water will flow through said fill assembly toward said outlet; means for securing said stack to the earth; said closed sides being constructed from a plurality of stacked rings; and means for securing each ring to its adjacent rings; each of said rings comprising: a plurality of prefabricated substantially similarly shaped modular unit secured to each other in side by side relationship; and means for securing each modular unit to its adjacent modular unit; each of said modular units further comprising: a horizontal member wherein the horizontal member of each of said modular units includes first and second structural members taperingly spaced apart by a plurality of shorter members so that a generally circular ring is formed when the modular units are secured to each other; a vertical member having one extremity secured to and extending from one extremity of said horizontal member, a first cross member extending angularly from the interesection of said horizontal member and said vertical member toward the intersection of the horizontal member and vertical member of an adjacent modular unit; and a second cross member extending between the other extremity of said horizontal member and the other extremity of said vertical member.