MODULAR COOLING TOWER
This invention relates to a modular cooling tower.
One common form of industrial cooling tower is a counter- flow tower in which warm water falls downward through one or more layers of fill or packing material, while cooler air moves upward through the layers of fill or packing material. The term "counter-flow" refers to the fact that the warm water and the cool air are moving in opposite directions through the tower.
Another common form of industrial cooling tower is a cross- flow tower in which warm water falls downward through one or more layers of fill or packing material, while cooler air flows across the fill or packing material approximately at right angles to the general direction of flow of the water.
Typically, industrial cooling towers are very large structures with deep foundations, having lateral dimensions of the order of six to thirty metres and a height of the order of six to ten metres. Such structures are built on site and typically the time delay between the time of order and the time of completion is about one year. The construction of such a cooling tower is a major civil engineering undertaking, involving the use of timber, steel and concrete. These large cooling towers are permanent
structures and do not lend themselves to disassembly, alteration or relocation. Cleaning and/or replacement of the fill or packing material are also major undertakings.
US-A-5 227 095 describes a modular cooling tower which includes an integral one-piece frame and basin preferably constructed from moulded fibreglass, the cooling tower module including a liquid distribution system, fill material located below the liquid distribution system, a drainage collection system located below the fill material, and at least one fan located below the drainage collection system. Each module can be lifted into place with a crane and the various modules can be bolted together. However, the modules themselves do not readily lend themselves to disassembly, alteration or relocation and cleaning and/or replacement of the fill or packing material is problematic.
It is therefore an object of the present invention to provide a modular cooling tower which overcomes or at least ameliorates the above disadvantages.
According to the present invention there is provided a modular cooling tower comprising a plurality of separable modules, the modules comprising:
a first module adapted to receive cooled liquid^ ' he first module including an outlet;
a second module provided with packing to facilitate heat exchange between liquid to be cooled and air flowing through the packing, the second module being positioned above the first module; and :5 a. third module provided with means for distributing liquid ;to...'be cooled onto the packing of the second module, the ~thiird module being positioned above the second module.
0 The cooling tower may include a plurality of second modules .
The modules may be separable by means of internal or external flanges provided at least at an upper or lower 5 edge of the interconnected modules. For example an upwardly or downwardly extending peripheral flange may be provided to engage around the side wall of an adjoining module. Alternatively, the outer surface of the side wall may be formed with a rebate to receive the side wall, 0 which may be internally rebated, of an adjoining module. As a further alternative, adjoining modules may each be provided with radial flanges.
The means for distributing liquid to be cooled may comprise one or more sprinklers and/or spray heads.
In one embodiment of the invention an air intake module is separably positioned between the second module and the
first module, the air intake module being provided with one or more openings extending in a circumferential direction around a side wall of the module. The or each opening may be provided with louvres. ,5:
A -plurality of air intake modules may be provided.
-'A_,dχiftr "eliminator module may be separably provided above the -third module and including a drift eliminator element 0 for reducing or eliminating droplets entrained in the air.
A fan module may be separably provided above the third module, and preferably above the drift eliminator module, for inducing air flow through the tower. The fan module 5 may include a motor for rotating the fan.
A cowl may be separably provided at the top of the tower.
In another embodiment of the invention the or each second 0 module may be provided with an air intake opening in part of a side wall thereof and with an air outlet opening in a further part of the side wall generally opposite the air intake opening. Thus air flows transversely,'across the module. The air intake opening may be provided with 5 louvres. A drift eliminator element may be positioned between the packing and the air outlet. A rfan ;:'may--be provided between the packing and the air outlet; ,,iideall.y between the drift eliminator element and the outlet.;.'
In order to increase thermal capacity, the modular cooling towers may be arranged in clusters. The cooling towers of a cluster may be arranged laterally and/or may be stacked.
For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:
Figure 1 is a diagrammatic cross-sectional view of one embodiment of a modular cooling tower according to the present invention;
Figure 2 is a plan view showing one manner in which the modular cooling towers according to the present invention may be laid out; and
Figure 3 is an end view showing one manner in which the modular cooling towers according to the present invention may be stacked; and
Figure 4 is a diagrammatic cross-sectional view of another embodiment of part of a modular cooling tower according to the present invention.
The modular cooling tower shown in Figure 1 'comprises ;a number of modules 1, each module having essentially-' the same plan in order that the modules may be stacked -.one upon
the other. The plan may be circular, square, rectangular, hexagonal or any other convenient shape. Each module has a side wall 3 of substantially constant dimensions with the lower edge of the side wall of an upper module co-operating with an upper edge of the side wall of a lower module in
'order that the modules can readily be stacked. For
•'.example, as shown in Figure 1, the upper edge of the side wall, of each module 1 may be provided with an upwardly extending peripheral flange 5 which engages around the lower edge of the side wall of the module above so as to retain the lower edge of the side wall of the upper module bearing on the upper edge of the side wall of the lower module. Clearly, other means may be provided for interconnecting the modules. For example, the outer surface of the side wall may be formed with a rebate to receive the side wall, which may be internally rebated, of an adjoining module. Alternatively, radial flanges may be provided at the lower and upper edges of the side wall . The modules may be secured to form a tower either by interconnecting adjoining modules or, for example, by passing strapping means (not shown) over the top of the tower to urge the modules downwardly in order to maintain the interconnection.
Adjoining modules may be provided with a releasable sealant to inhibit the loss of liquid from the tower. 'The sealant may be, for example, a silicone-based sealant . qr an
elastomeric material such as of rubber or PVC, which may be foamed.
The lowest, or first, module is in the form of a sump unit 7 for accumulating cooled liquid. The sump unit comprises a peripheral side wall, an upwardly extending peripheral flange for interconnecting with the module above and for minimising leakage of liquid from the tower, and a lower wall 9 closing the bottom of the unit. An outlet 11 is formed in the side wall to allow cooled liquid to flow out of the cooling tower.
Above the sump unit is provided at least air intake unit 13 to allow cooling air to enter the tower, a single air intake unit being shown in the drawing. The air intake unit comprises a side wall having an upwardly extending peripheral flange around the upper edge of the wall and a short inwardly extending flange at the lower edge of the wall to facilitate contact with the upper edge of the side wall of the sump unit and/or to direct drips and/or spray into the central region of the tower and away from the wall thereof. The side wall of the air intake unit 13 is provided with one or more openings 15 extending in the circumferential direction, the openings being partly.closed by louvres 17 to exclude light and solid material: from,.. he
Λ tower.
Above the air intake unit 13 is provided one or more second modules in the form of fill or packing (hereinafter "packing") units 19 which facilitate contact between the liquid flowing down the tower with air flowing up the tower. Although two packing units are shown, the number of packing units will depend on the specifications for each particular tower. The or each packing unit comprises a side wall having an upwardly extending peripheral flange around the upper edge of the wall and a short inwardly extending flange at the lower edge of the wall to facilitate contact with the upper edge of the side wall of the module beneath and/or to direct drips and/or spray towards the central region of the tower and away from the wall thereof . Supported in known manner within the packing unit is a fill or packing (hereinafter "packing") material 21 of conventional type.
Above the, or the uppermost, packing unit 19 is provided a third module in the form of a deluge unit 23 which introduces into the tower a liquid to be cooled and assists
extending peripheral flange around the upper edge of the wall and a short inwardly extending flange at the lower edge of the wall to facilitate contact with the upper edge of the side wall of the module beneath. One or more sprinklers or spray heads 25 are provided within the deluge / ϊ>|k> unit, connected to a supply of liquid to be cooled.
Above the deluge^unit 23 is provided a drift eliminator unit 27 to reduce or eliminate liquid droplets from the air leaving the tower and to exclude light from the tower. The drift eliminator unit comprises a side wall having an upwardly extending peripheral flange around the upper edge of the wall. Although not shown, a short inwardly extending flange may be provided at the lower edge of the wall to facilitate contact with the upper edge of the side wall of the module beneath. Supported within the upper part of the drift eliminator unit, for example by way of an inwardly extending flange 29, is a drift eliminator element 31 of known form.
Above the drift eliminator unit 27 is provided a fan and motor housing unit 33 for inducing a flow of air upwardly through the tower. The fan and motor housing unit comprises a side wall in this case not provided with an upwardly extending peripheral flange around the upper edge of the wall. Although not shown, a short inwardly extending flange may be provided at the lower edge of the wall to facilitate contact with the upper edge of the side wall of the module beneath. Supported within the unit 33 in known manner is a motor 35 drivingly connected to a fan 37.
Above the fan and motor housing unit 33 is provided a cowl 39 for improving the efficiency of the fan and to provide protection for the fan and motor.
In use of the tower, liquid to be cooled enters by way of the sprinkler 25 and flows downwardly through the tower over the packing material 21 into the sump unit 7, from which it exits by way of the outlet 11. Air enters through the openings 15 in the air intake unit 13 and passes upwardly through the tower, contacting the liquid in the packing units 19 to cool the same, passes through the drift eliminator unit to reduce or eliminate droplets entrained in the air, and is forced out through the cowl by the motor and fan combination.
The individual modules may be constructed of any suitable material, such as wood, plywood, fibreglass, metal (coated or uncoated) , plastics and/or concrete. The modular construction enables the cooling tower to be quickly and easily constructed and dismantled without the need for special tools or skills. For example, the tower can readily be dismantled to facilitate cleaning and/or replacement of the packing material and/or to add or remove air intake units and/or packing units in order to modify the thermal capacity of the tower. It should be noted the fan and motor housing unit is not needed in natural draft cooling towers and can therefore be omitted.
Thus the modular construction permits a number of improvements, including:
the manufacture and/or fabrication of the modules in a factory environment;
easy transportation of the cooling tower in modules to the required site;
the ability to deploy the cooling tower without the need for deep and/or complex foundations;
simple and rapid assembly of the cooling tower on site, without the need for special tools and/or skills;
disassembly of the cooling tower for cleaning, maintenance, repair or transportation without the need for special tools and/or skills.
Moreover, the required thermal capacity need not be met by a single tower, but rather can be met by providing a number of separate towers. Such towers can be located at ground level, for example by arranging the towers in clusters as shown in Figure 2. Alternatively, the towers can be stacked, for example as shown in Figure 3.
The part of the modular cooling tower shown in Figure-,.4 is di ferent to that in Figure 1 in that the flow of ..air-is transversely across the tower. To this end, a.:,numbe - of the modules of the tower of Figure 1 are cottibine -into a
single multi-purpose second module 41, the combined modules including the air intake unit 13, the packing unit(s) 19, the drift eliminator unit 27 and the fan and motor housing unit 33.
Thus, the tower of Figure 4 incorporates a sump unit such as that shown in Figure 1, one or more multi-purpose modules 41 as will be described in more detail hereinafter, a deluge unit such as that shown in Figure 1, and a cowl unit such as that shown in Figure 1 or other suitable closure .
The multi-purpose modules 41 each comprise a peripheral side wall 3 having an upwardly extending peripheral flange 5 which extends around the outer periphery of the side wall and engages around the lower edge of the side wall of the module above so as to retain the lower edge of the side wall of the upper module bearing on the upper edge of the side wall of the lower module. As with the embodiment of Figure 1, clearly other means may be provided for interconnecting the modules.
Part of the side wall is provided with an air intake opening 43 partly closed by louvres 45. A further part of the side wall, generally opposite the air intake opening, is provided with an air outlet 47. Within • the module adjacent to the air intake opening 43 there is supported a packing material 49 of conventional type, and within the
module adjacent to the air outlet 47 there is supported a motor 51 drivingly connected to a fan 53. Between the motor 51 and the packing material 49 there is supported a drift eliminator element 55.
In use of a tower incorporating the modules of Figure 4, liquid to be cooled enters by way of a sprinkler or the like provided in the deluge unit and flows downwardly through the tower over the packing material 49 in the or each multi-purpose module, and into the sump unit, from which it exits by way of an outlet . Air is drawn in through the air intake opening of the or each multi-purpose module and flows through the packing material 49 transversely to the general direction of flow of the liquid, contacts the liquid to cool the same, passes through the drift eliminator unit 55 to reduce or eliminate droplets entrained in the air, and is forced out of the air outlet 47 by the motor and fan combination.