Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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~i, FIELD pF THE IN~ENTI0N
The invention relates to water coolant systerns incorporating
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a heat exchanger which is coolecl by means of air chilled by water
~!, evaporation, and to an o~one treatment systern for preventing
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microbiological growth in the coolant water and in the evaporation
water, and to the elimination of excess ozone, and to a heat
exchanger for such a system.
BACKGROUND OF THE INVENTION
~; Many cooling systems ernploy a closed circuit system of water
flow devices with or without radiators, located at strategic
positions within a facility such as a building. The water flow
devices and/or radiators are connected by pumps and suitable
conduits to a heat exchanger, in many cases located on the roof of
~; the building, or simply to one side of it.
In order to cool the water in the closed circuit system, the
water is usually passed through one or more heat exchangers.
Evaporative water is then sprayed as a mist into air passing
through the heat exchangers~ by fans creating an air stream passing
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~ ~ through the heat exchangers. In this way the water mist is
,,~! ~ 20 evaporated and chills the heat exchangers. The sensible heat of
the water in the closed circuit system is reduced, by the latent
~ heat of evaporation of the water sprayed into the air passing
;.~. through the heat exchanger.
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~ Such systerns have been in general use for many years.
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However, they suffer frornvarious disadvantages. The water in
the closecl circuit system tsnds to bscome contarnirlatsd, and also
accurnulates scale within the system thereby reducing the sfficiency
of the clrculatlon. In acldltlon, the evaporatlve water spray
systern rapidly picks up microbiological contarnination, and the
system becomes both unhealthy, and less and less efficient.
~-iSimilar problerns occur in many other forms of water
circulation systems. For example, in water circulation systems in
swimming pools, relatively substantial quantities of harsh
chemicals are added to the water on a daily basis, or sometimes are
continuously leached into the water in some systems J to prevent
microbiological growth within the pool water itself, and also to
prevent contamination of the plumbing of the system.
;-Various proposals have been made for the purification of the
;water by means of subjecting it to the passage of ozone gas. The
`ozone gas destroy the microbes in the water, and rapidly combines
into harmless byproducts.
Ozone generators are however, relatively inefficient, and tend
to consume large amounts of electrical energy to generate
relatively small volumes of ozone gas. Conversely, if sufficient
~ozone gas is generated to provide a continuous efficient treatment
!.~of the water, it involves the consumption of excessive amounts of
electrical powsr, and also, it is virtually inevitable that some
free ozone gas will escape, and this is undesirable.
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~,'Other problems in earlier systems have been generally centred
around the design of the heat exchanger itself. This usually
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consisted of a plurality of tubes, connected to headers, with the
closed circuit water being passed through the tubes while they were
subjected to a water spray
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,,1~ This led to a relatively inefficient transfer of heat.
~- Consequently 7 very large volumes of water had to be sprayed
continuously, and high power fans had to be employed, to ensure
sufficient air flow to evaporate the water at an adequate rate~ to
transfer the heat from the system water to the evaporation water.
These factors also have reduced the actual efficiency of the
systems and increased both their capital cost and their operating
~ cost.
;., It will of course be apparent that while in many such systems
the closed circuit cooling liquid is water J it may~be some form of
, a coolant liquid, including any form of anti-freeze chemical such
as ethylene glycol or the like, for example. In many of the water
evaporative circulation system, the evaporative water is contained
essentially in an open topped tank, from which it is pumped
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upwardly to one or more sprayheads, and then sprayed directly into
the air stream or over the heat exchanger, with the water running
down from the heat exchanger back into the tank. Such a system is
a highly suitable medium for the growth of bacteria of many kinds
since it is both highly aerated, and is constantly warmed. For all
of these reasons, therefore, there is considerable room for
improvement in such evaporative cooling systems, giving rise both
~, to reduced capital costs and reduced operating costs, and reduced
~'! health risks.
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j BRIEF SUMMf~RY OF THE INVENTION
With a view, therefore~ to providing irnproved solutions to the
~ forsgoing problems, the invention comprises an evaporative cooling
.~ system for us~ in association with a process coolant fluid
. circulating system, said coolant system including heat exchanger
rneans, connected in circuit by suitable conduits, and wherein said
~ heat exchanger means comprises a plurality of tubes extending
generally parallel to one another, first and second header tank
means at opposite ends of said tubes, heat exchange fins mounted on
.!'' 10 said tubes transversely thereof, evaporation water tank means
, locatsd below said heat exchanger means, and pump and spray means
for spraying evaporation water from said tank means, fan means for
forcing air through said heat exchanger means and around said fins,
~ whereby to evaporate at least some of said evaporation water
i^ thereby both cooling said air and removing the heat from process
coolant fluid circulating within said heat exchanger means, vent
means for venting air and vaporized water to atmosphere, ozone
generator means associated with said tank means, and air conduit
means connected to said ozone generator means, and gas conduit
:. 20 means connected from said ozone generator means to said tank means,
for transferring ozone-rich gases to said tank means from said
ozone generator means, whereby to reduce bacterial growth in said
evaporation water in said tank means.
The invention further comprises such an evaporative system and
including header tank connection means, for connecting said tubes
thereto, said header tank connection rneans comprising end
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,~ formations on each end of eaGh of said tubes 7 said end forrnations
~ defining generally annular ribs formed around said ends~ and
'."~ adapted to abut against portions of said header tanks, and further
including reduced diameter neck portions adapted to extend through
openings in said header tanks, and further deFinin.g outwardly
~, expanded collar portions, formed integrally with said neck
portions, and angled ou-twardly therefrom~ whereby to secure said
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~ neck portions in said header tanks,
':~ The invention further comprises such an evaporative cooling
~, 10 system and including ozonation chamber means in said evaporative
~, water tank means, and ozonation inlet means at the bottom end of
,, said chamber means, and ozone outlet means at the top end of said
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chamber means, and a plurality of upwardly angled deflector plates
secured in said chamber means, said deflector plates being secured
alternately on opposite sides thereof, and extending partially
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across said tank means, and alternately overlapping adjacent said
plate means located on the opposite sides of said chamber means
whereby to define a generally zig-zag path for flow of ozone-
containing gases passing from said inlet means upwardly through
~ ~ 20 said chamber means to said outlet, whereby to provide an elongated
,~ path for flow of said ozone-containing gases through said water
within said ozonation chamber~
The invention further comprises such an evaporative cooling
system wherein said coolant fluid is a liquid and including a
coolant liquid ozonation chamber connected in said coolant fluid
circulation system, and having a lower end and an upper end, an
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ozone gas inlet rneans at said lower end of said charnber~ and an
ozone gas outlet means at an upper end o-F said charnber, and
deflector plates mounted in said chamber alterrlately on opposite
s sides, ancl extending across said chamber in an upwardly angled
orientation, whereby to deFine a ~enerally zig-zag Flow path ~For
ozone containing gases passing upwardly through said chamber, and
coolant fluid inlet and outlet means in said chamber, whereby
coolant fluid may flow through said chamber, and whsreby ozone
containing gases may ~low through said chamber, and whereby said
ozone containing gases may be contact and be intermingled with said
coolant fluid, during passage through said chamber.
The invention further comprises such an evaporative cooling
system and including ozone gas reaction means located at said ozone
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gas outlet of each of said chambers, whereby excess ozone gas
~3 exiting from said chamber, is converted into harmless by-products.
The invention further comprises such an evaporative cooling
~r system wherein said ozone conversion means comprises particles
;. including titanium dioxide, adapted to react with said ozone, and
procure a catalytic conversion thereof into harrnless by-products.
The invention further comprises such an evaporative cooling
-~ system and wherein said ozone generator comprises an elongated
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conduit, with air inlet means at one end, and gas outlet means at
the other, a first electrical high tension electrode located within
said elongated conduit a second electrical high tension electrode
located spaced from said first electrode, whereby air passing along
said elongated conduit is subjected to the action of a hi~h tension
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electrical potential between said electrodes over an elongated flow
path thereby procuring generation of ozone gas along the length of
~ said elongated flow path
1~ The invention further comprises an ozone generator comprisiny
an elongated conduit Forrned wi~h at least one curve thsrein,
whereby to define a curved elongated flow path7 and air inlet means
at one end, and gas outlet means a-t the other end7 and said first
.~ electrical high tension electrode extending throughout said
elongated conduit, and means -for flowing air along said conduit,
and subjecting the same to said high tension electrical potential
whereby to generate an air gas ozone mixture exiting at said gas
outlet end of said flow path.
The various features of novelty which characterize -the
~s invention are pointed out with more particularity in the claims
annexed to and forming a part of this disclosure.. For a better
understanding of the invention, its operating advantages and
s:.: specific objects attained by its use, reference should be had to
the accompanying drawings and descriptive matter in which there are
illustrated and described preferred embodiments of the invention.
N THE DRAWINGS
Figure 1 is a perspective illustration of an evaporative
cooler in accordance with the invention,
~, Figure 2 is a section along the line 2-2 of Figure 1;
~,~ Figure 3 is a schematic cut-away perspective of the heat
exchanger of the unit of Figure 1;
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~ Figure 4 is an enlarged section along line 4-4 of Figure 3;
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Figure 5 is a schernatic cut-away perspectlve illustration of
'!'' an o~onation chamber of Figure 1;
.~ Figure 6 is a cut away pers~ective illustration of the ozone
i:j generator of Figure 2i
Figure 7 is a section along the line 7-7 of the o~one
. generator of Figure 6, and,
Figure 8 is a section along line 8-8 of Figure 7
DESCRIPTION OF ~ SPEC I F I C EMeOD I MENT
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Referring first of all to Figure 1, it will be seen that this
discloses in general terms an evaporative cooling unit in
. accordance with the invention indicated generally as 10.
:; It comprises a generally rectangular housing or casing, having
side walls 12 - 12, end walls 14 and 16 and a top wall 18. In the
~ lower portion of the housing 10, there is a generally rectangular
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~: evaporative water tank, (Figure 2) having side walls 20, extending
from end wall 14, to an intermediate partition wall 22, and a
,! bottom wall 24 (Figure 2).
, ~t the one end 14 of the housing 10, there is an air intake
screen 26, and at the opposite end of the upper wall 18, there are
air outlet vents 28.
Referring now to Figure 2, the interior of the housing 10,
will be seen to have an intermediate generally horizontal partition
wall 30, extending from side to side between the side walls 12
12, and extending from the lower extremity of the air intake screen
26, to a point intermediate the two end walls 14 and 16
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A heat exchanger 32 i5 mounted between the free end of the
partitior, 30, and an interior upper wall 34~ and essentially
. divides the interior of the ho~lsing 10 into air intake and air
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outlet compartments.
A fan 38, driven by any suitable motor 40, is mourlted on, for
example, struts 42, and is operable to draw air in through the air
intake screen 26 and force it throuyh the heat exchanger 32~ and
out of the air vents 28.
etween the fan 38 and the heat exchanger 32, there are one
~ 10 (or more~ water mist spray heads 44, supplied by means of a pipe 46
and pump 48.
The function of the water spray, is to both provide water to ~ -
evaporate in the air stream created by the fan to chill the air
stream, and also to cause the continual impingement of a water
spray on the heat exchanger 32, whlch water spray will then be
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further evaporated by the already chilled air stream, thus causing
chilling of the heat exchanger.
~ generally upwardly curved baffle 50, guides the air flow
from the heat exchanger Up through the air diverter blades 52. The
air blades 52 are generally V-shaped and act as a trap for any
entrained water droplets which have not been evaporated, so that
such entrained water droplets will continually drip down from the
air blades 52, and flow down the baffle 50 back into the lower
portion of the apparatus.
In order to maintain the sanitary bacteria-free status of the
evaporative water in the lower portion of the cooler, an ozone gas
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generator indicated generally as 60 is provided in the unit. Gas
generator 60 is adapted to draw air in through inlet 62, and to
discharge ozone containing gases and air upwardly in a manner
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described below, and downwardly, through pipes 6~ and 66
respectively.
Pipe 66 is connected to an ozonation chamber 68, located at
one end of the evaporative water container. The purpose of the
ozonation chamber 68 is to disperse ozone gas throughout the
evaporative water in the tank, and operates in a manner to be
described below. Chamber 68 has a suppl~ pump 69.
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The upper conduit 64 connects to a further ozonation chamber
70, the function of which is to disperse ozone throu~hout the
coolant heat exchange media, in a manner to be described below.
Referring now to Figures 3 and 4, the heat exchanger 32 will
be seen to be cons-tructed and comprised as shown in Figure 3. It
~consists of a pluralitY of cylindrical tubes 76J extending parallel
i,;and spaced apart relation, and having at each end respective header
,tanks 78 and 80. ~long the length of the tubes, there are located
a plurality of heat exchanger fins 82. The ends of the tubes are
fitted into the respective header tanks, as shown in Figure 4. It
will be seen that this fitting consists of a reduced neck 84,
fitting within a hole 86 in the header tank. The neck has, on the
~;tube side of the header tank, a expanded collar 88. On the header
tank side, the end oF the tube is swaged out to provide a trumpet-
shaped mouth 90. This securely holds and seals the tube in the
header tank.
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The fins are provided necks 94, adapted to rnake a snug
frictional fit on the tubes and thus provide ~ood heat exchange
efficiency.
Referring now to Figurss 5~ in each of the two ozonatior
chambers 66 and 70 will be seen to comprises a substantially
identical construction.
This consists of a generally rectan~ular box-like tank 100
having an gas inpùt opening at 102 at its lower end and gas output
opening 104 at its upper end.
~;. 10 Within the main portion of the tank, there are provided a
series of upwardly angled deflectors or baffles 106, the purpose of
which is to provide a zig-zag flow path for water flowing through
the chamber. ~t the top of the chamber, in order to prevent the
release of unwanted excess ozone gas, the chamber is provided with
a mesh grid 110. On top of the grid, there are provided a large
plurality of reactive particles 112. Typically, these will have a
~ catalytic reaction on the o~one. Titanium oxide is preferred.
J;~ This has a highly satisfactory reaction with ozone, and
converts it into hartnless gases which can then be vented to
atmosphere.
Ozonation chamber 68 is located within the evaporation water
itself, and water flow therethrough will be maintained via pipes
113 and 114 and any suitable pump mechanism (not shown) to maintain
a gentle steady flow of water up~ardly through the chamber 68, and
`$ exiting through the top.
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The ozonation gases at the top oF the charnber will bs
converted in a manner described above, and will simply be emitted
as harmless gases.
The ozonation chamber 70 functions in essentially the same
way. In this case, the circulation water is flowed through the
return pipe 115 to the lower end of the heat exchanger 32 and then
upwardly to pipe 116. This pipe is connected to the top of the
ozonation chamber. The distribution pipe 118 is connected to the
bottom of the ozonation chamber. In this case water will flow
downwardly, in a counter-current flow relative to the upward flow
of the gases, and will produce intimate intermingling of ozone with
the system water.
~ gain, harmless ozone gases which have been converted by the
catalytic conversion particles at the top of the chamber, will be
allowed to exit to atmosphere.
In order to generate ozone gases in sufficient quantity and at
a reasonable power consumption, an ozone generator indicated in
Figures 6 J 7, and 8 is provided.
The ozone generator is indicated generally (in Figure 2) as
50. The ozone generator 50 comprises a generally rectangular
housing 120, which is provided with an input conduit 122 and exit
conduit 124. Within the chamber, there is provided an essentially
zig-zag flow treatment tube assembly 126, consisting of a series o-f
bent loops of conduit material. Typically, thermoplastic material
`~ is suitable, and is preferred.
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~ Within the tube assernbly 126, there is provided a centre
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electrode wire 128. The wire enters through an entry port 130 from
a high tension supply cable 132y connected to transformer 133.
The high tension supply cable 132 is of the coaxial type, and
has an exterior conductive wire body 13~. The wire body 134 is
secured to the owtside of the tube by a screw 136. The centre 137
of the coaxial cable, and the wire sheathing, enter the housing of
the ozone generator through separate insulated grommets 138 and
140.
Around the exterior of the tube, is provicled an electrical
conductive sleeve 142. The sleeve 142 provides the secondary
electrode for the ozone generator. A tube 144 of thermoplastic
material provides a dielectric wall separating the centre primary
electrode from the exterior secondary electrode~
When a high tension voltage is applied via the coaxial cable,
the dielectric wall being spaced from the prlmary electrode,
provides a barrier to reduce and eliminate a tendency for very high
voltage sparks to jump between the two electrodes at different
.~ places. The corona discharge that takes place lS thus spread out
along the length of the tube and maximizes the efficiency of the
treatment of the air to generate ozone.
~ir is pumped into the input end of the tube by any suitable
~;~ pump means and pipe 62 ~Figure 2).
~ ir and ozone gas is emitted from the output end of the tube,
to the ozone conduits 64 and 66 conn0cted to the two ozonation
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~ chambers 68 and 70
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In this way, the single ozone generator is effective to
provide ozone-rich gases to both ozonatiorl chambers
In operation, the fan 38 will force air through the water
spray 44, and thus evaporate some of the water vapour irnmecliately
and chill the air. The air will then flow through heat exchanger
82, and being at a reduced temperature, and also carrying water
droplets, it will still further e~aporate the water vapour on the
hsat exchanger, and in so doing, will extract the latent heat of
vaporization from the radiator itself. ~ny water droplets that
10remain, or condense on the radiator can drip downwardly into the
tank 24.
Air and entrained water vapour is forced through the baffles
52 which further remove any water droplets, and air is then emitted
through the air vents 28 on top of the unit (Figure 1).
Water is continuously supplied to the tank from any suitable
water supply indicated generally as 150 (Figure 2).
This water supply will incorporate in the usual manner a level
valve, by means of which the admission of water to the tank is
controlled within appropriate limits.
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20Bacterial growth within the evaporation water in the tank is
controlled by the ozonation chamber 68. Bacterial growth in the
system circulating water is controlled by the ozonation chamber 70.
In this way, the water both in the evaporation portion and in the
~ system circulating cooling water, is controlled and kept sterile.
.; The entire unit i5 compact and simple to operate and requires
a minimum of electrical power as compared with earlier units. In
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additionJ it will have a much greater service li-Fe, and will
prevent the build up of long term problems in tne system
circulating pipes, such as has been comrnon in the past.
The foregoin~ is a description of a preferred embodiment of
the invention which is given hers by way of example only~ The
inventiorl is not to be taken as limited to any of the specific
features as described~ but comprehends all such variations thereof
as come within the scope of the appended claims~
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