Cooling tower

A counter-flow forced-draft type cooling tower comprising an outer structure, the top of which has an opening, a centrifugal fan which is an integral part of a rotatable cylinder. The rotatable cylinder has numerous small apertures. A screen which is coaxial with the cylinder. A motor mounted underneath the cylinder which rotates the cylinder. An annular corrugated water guiding plate on the side wall of the outer structure, an inclined water collecting plate under the water guiding plate. Ventilation louvers which are disposed underneath the outer structure. A water tank which is disposed under the louver to collect the cooled water and which has a floating valve to control the amount of water contained therein. The lower provides an inlet for outside air. The air then flows upwards, and is sucked into the rotating cylinder by the centrifugal fan, which also slings hot water radially out of the cylinder. Next the air goes out through the opening of the top cover. A spraying head which sprays water into the cylinder comprising the centrifugal fan. A guiding plate and a water collecting plate for controlling water flow.

BACKGROUND OF THE INVENTlON 
This invention relates generally to a cooling tower and in particular to a 
counter-flow forced-draft type cooling tower. 
Conventionally, cooling towers are divided into three types. These are the 
atmospheric, natural draft and forced draft types. These three types, in 
turn may be sub-classified into counter-flow or cross-flow type cooling 
towers. 
In an atmospheric type cooling tower, high temperature water is pumped to 
the top of the cooling tower, where it then falls as a free body. During 
the free fall period heat is transferred from the higher temperature water 
to the lower temperature air, thereby decreasing the temperature of the 
water. 
The atmospheric cooling tower has the simplest design of the three 
above-mentioned types, but its efficiency is quite low. 
In a natural draft type cooling tower, the cooling tower is basically a 
chimney which causes the low temperature air to flow upwards. High 
temperature water is then sprayed from the the top of the cooling tower, 
and falls downwards. When the water and air come into contact, heat is 
transferred from the water to the air. Since the flowrate of air within 
the cooling tower is affected by the wind speed around the cooling tower, 
its efficiency fluctuates. 
In forced-draft type cooling towers, low temperature air is drawn into the 
cooling tower mechanically. This increases the efficiency of heat exchange 
between the high-temperature water and the low temperature air over 
natural draft type cooling towers. However, a cross-flow forced-draft type 
cooling tower have a great disadvantage that it takes up more space than a 
counter-flow type cooling tower. 
Although the counter-flow forced-draft type cooling tower is more efficient 
than other types of cooling towers, it is still possible to improve it. 
Therefore the object of the present invention is to provide a counter-flow 
forced-draft type cooling tower with a higher heat exchange rate than 
prior art. 
As shown on FIG. 4, a conventional counter-flow forced-draft type cooling 
tower usually has a fan 201 disposed above the cooling tower 200'. This 
can be improved as shown on the following detailed description to increase 
its function. 
SUMMARY 
A primary object of this invention is to provide a cooling tower whose 
efficiency is greater than that of prior arts. 
Another object of this invention is to provide a cooling tower which is 
both simple in structure and useful in air-conditioning systems. 
Further objects and advantages of the present invention will become 
apparent as the following description proceeds, and the features of 
novelty which characterize the invention be pointed out with particularity 
in the claims annexed to and forming a part of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings, and in particular to FIG. 1, it can be seen that 
the present invention comprises an outer structure 1, a motor 2 which is 
fixed on a bracket 5, a rotating cylinder 3, a screen 4 concentrically 
positioned around the cylinder 3, a water guiding plate 6 and a water 
collecting plate 7 attached to the outer structure 1, a water tank 8 under 
the outer structure 1, a floating valve 9 which is mounted on the tank 8, 
a louver 10 between the outer structure 1 and the tank 8 for ventilation, 
and the base 100 which supports the whole structure. 
The outer structure 1 comprises a side wall 11 under which a louver 10 is 
connected, and a top cover 12. The top cover 12 of the outer structure 1 
has a circular opening 13 in the center. Low temperature air comes into 
the cooling tower through the louver 10, passes through the interior of 
the outer structure 1 and goes out through the opening 13. 
The edges of the opening face inwards to form an inclined portion 14 which 
prevents recirculation of air from the gap 15 between the top cover 12 and 
the cylinder 3. 
There is a bracket 5 inside the outer structure 11 to support the motor 2 
and the rotatable cylinder 3. The bracket 5 has four legs 52 secured on 
beams 51 and supports the motor seat 53. The motor seat 53 in turn 
supports the motor 2. The motor 2 in the motor seat 53 engages with the 
bottom 31 of the rotatable cylinder 3 with its spindle 21. The main power 
supply 110 is on the side wall 11 and supplies the motor 2 with electric 
power. 
Referring to FIG. 2, it can be seen that the rotatable cylinder 3 comprises 
a bottom portion 31, a holed portion 32, a centrifugal fan 33 and a top 
portion 34. The holed portion 32 has a plurality of apertures 35 which 
allow the water droplets to be slung outwards. The centrifugal fan 33 
comprises a plurality of blades 36 which are secured between the first and 
second flanges 37 and 38. The first flange 37 is secured on the top 
portion 34, the second flange 38 is secured on the holed portion 33. The 
centrifugal fan 33 rotates along with the cylinder 3, drawing the air from 
the interior of the outer structure 1 into the cylinder 3 and propelling 
this air out of the outer structure 1 through the opening 13. Therefore an 
air flow is generated within the outer structure, with low temperature air 
being continuously drawn into the outer structure. The top portion 34 is 
as close as possible to the top cover 12 in order to decrease the width of 
the gap 15 between the top cover 12 and the cylinder 3. This reduces 
recirculation of air within the cylinder 3. 
Referring to FIG. 3, a screen 4 comprises a frame 41, which includes a 
flange 42 and a skirt 43 and a net 44 which is adherent to the frame 4. 
The screen 4 is secured concentrically around the rotating cylinder 3 
under the top cover 12 of the outer structure 1 by fixing the flange 42 to 
the top cover 12. The net 44 partially blocks the water droplets and 
further divides them into smaller droplets, which in turn increases the 
overall surface area of the water which is available for heat exchange 
with the low temperature air. The skirt 43 functions as both a guide for 
the water and a water guard for the motor seat 53. 
An annular water guiding plate 6, which is corrugated in order to guide the 
water droplets and increase the surface area of the water which contacts 
with the low temperature air, is slanted downwards between the skirt 43 
and the beams 51 thereby guiding its flow to a water collecting plate 7, 
then to the water tank 8. 
An annular water collecting plate 7 which is also slanted downwards from 
the side wall 11 below bracket 5 guides water to the central opening 71. 
The water then falls into the water tank 8. 
The water tank 8 receives and stores the water. The amount of water within 
the tank 8 is controlled by a floating valve 9, which is connected to the 
water tank 8. When the tank is full, the valve 9 cuts off the supply of 
water. The water within the tank 8 flows out via the outlet 81. A control 
valve (not shown in the drawings) may be provided at the outlet 81 to 
control the out-flow of water. 
A louver 10 is disposed between the outer structure 1 and the water tank 8 
in order to allow the low temperature air to enter freely. A base 100 
supports the whole structure. 
Piping 101 serves as a conduit for high-temperature water to flow to the 
opening 13 on the top cover 12. Preferably, a sprayer head 102 is attached 
to the piping 101 to disperse the high temperature water into droplets so 
as to increase the heat exchange between the high temperature water and 
the low temperature air. 
The operation of the cooling tower 200 of the present invention is decribed 
as follows. 
High temperature water is sent through piping 101 to the sprayer head 102 
by a pump (not shown) or some other means. The sprayer head 102 disperses 
the high temperature water into droplets which will fall downwards towards 
the rotating cylinder 3. 
Some of the water is slung out through the apertures 35 in the cylinder 3 
before reaching the bottom 31 of the cylinder 3. This is a result of the 
centrifugal force caused by the rotation of the cylinder 3. The remaining 
portion of the water falls to the bottom portion 31 of the cylinder and is 
also slung outwards by the centrifugal force of the cylinder. 
Some of the droplets which are slung out of the cylinder 3 hit the screen 4 
and drop to the skirt 43. Some reach the screen 4 and pass through the net 
44. The rest fall to the skirt 43. The water then flows by gravity to the 
guiding plate 6 and then to the collecting plate 7. Then it flows down to 
the water tank 8. Simultaneously, low temperature air is drawn into the 
outer structure 1 by a centrifugal fan 33 where it passes through the 
central opening 71 and flows upwards. It is then sucked into the fan 33 
and propelled out of the outer structure 1 through the opening 13. 
Since the flow of air from the fan 33 is opposite to the direction of water 
droplets' flow, the high temperature water is cooled along its way to the 
water tank 8. When water droplets are slung out of the cylinder 3 and the 
screen 4, they mix with air flow from the central opening 71 and their 
temperature is further decreased. Then, the water droplets fall downwards 
and their temperature is further decreased to an acceptable level due to 
the heat transfer between the high temperature water droplets and the low 
temperature air which is drawn in through the louver 10. Therefore, when 
the water finally flows into the water tank 8, its temperature is low 
enough for reutilization or for disposal into the environment. 
As various possible embodiments might be made of the above invention 
without departing from the scope of the invention, it is to be understood 
that all matter herein described or shown in the accompanying drawing is 
to be interpreted as illustrative and not in a limiting sense. Thus it 
will be appreciated that the drawings are exemplary of a preferred 
embodiment of the invention.