Precooler for an evaporative cooler

An auxiliary cooler shell for installation over and around a conventional evaporative cooler for the enhancement of the cooling effectiveness and efficiency of the existing cooling system, the auxiliary shell incorporating evaporator pads and a water distribution spider that is supplied by the water pump of the conventional cooler over which the shell is installed.

BACKGROUND OF THE INVENTION 
With the advent of higher energy costs, the evaporative cooler as an air 
conditioning system is again assuming prominence in the marketplace. Its 
installation and operating costs are more economical than a refrigeration 
unit and even where a refrigeration system is needed, the trend is now to 
utilize both types working together to provide an air conditioning system. 
While the cost of operating an evaporative cooling system is considerably 
less expensive than that of a mechanical refrigeration system 
incorporating compressors and condensers, further improvements in the 
effectiveness and efficiency of the evaporative cooler are economically 
desirable. The present invention provides a means for enhancing the 
cooling efficiency of an existing evaporative cooler, the means comprising 
a set of auxiliary evaporator pads mounted in a shell that may be fitted 
over and around the existing cooler In this arrangement, the air to be 
cooled first passes through the auxiliary pads for precooling before 
entering the main evaporative cooler. 
DESCRIPTION OF THE PRIOR ART 
Numerous improvements in evaporative coolers have been conceived; however, 
more are needed for it to function effectively under all operating 
conditions and competitively with refrigeration systems. 
U.S. Pat. No. 2,091,198 describes an evaporative cooling system employing 
main and auxiliary cooling units. The auxiliary unit is positioned 
adjacent and upstream from the main unit with a common fan or blower 
placed therebetween. 
The present invention offers important improvements in form over this 
patented structure and results in a more practical and commercially 
acceptable product. 
U.S. Pat. No. 4,353,219 describes an evaporative precooler in the form of a 
jacket to be installed around three sides of a condensing unit of a 
mechanical refrigeration system. The present invention, however, is 
tailored for use with an existing evaporative cooler rather than with a 
refrigeration system, and it is therefore able to provide economies 
related to the common usage of water pumps, reservoirs and other water 
distribution and supply components that are not present in refrigeration 
systems. 
Numerous other improvements and variations in the evaporative cooling art 
are described in U.S. Pat. Nos. 3,147,319; 4,045,523; 4,101,609; 3,984,995 
and 3,290,866. The arrangements described in these patents, however, are 
not believed to anticipate the novelty of the present invention. 
SUMMARY OF THE INVENTION 
In accordance with the invention claimed, an auxiliary evaporative cooler 
shell is provided for use in the enhancement of the operation of an 
existing evaporative cooling system. The auxiliary cooler shell comprises 
a framework carrying evaporator pads on as many as four sides with 
provision for water distribution to the pads. The shell is intended to be 
placed over and around the existing cooler and it shares with the existing 
cooler the water pump and supply means as well as the air moving system. 
It is, therefore, an object of the present invention to provide an improved 
evaporative cooling system. 
Another object of the invention is to provide an auxiliary evaporative 
cooler shell that may be placed over an existing evaporative cooler to 
improve the operating effectiveness and efficiency of the cooling system. 
A further object of the invention is to provide such an auxiliary 
evaporative cooler shell in a form that provides for maximum common useage 
of water and air handling components already present in the existing 
evaporative cooling unit. 
A still further object of the invention is to provide such a cooler shell 
which, by virtue of such common useage, is inexpensive in terms of its 
initial manufacturing cost. 
A still further object of the invention is to provide such a cooler shell 
in a form which facilitates its installation over an existing cooler and 
which requires a minimum of additional mounting space. 
A still further object of the present invention is to provide such a cooler 
shell as a means for upgrading an existing evaporative cooler that has 
been found incapable of handling its required cooling load. 
Further objects and advantages of the invention will become apparent as the 
following description proceeds and the features of novelty which 
characterize this invention will be pointed out with particularity in the 
claims annexed to and forming part of this specification.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring more particularly to the drawings by characters of reference, 
FIGS. 1 and 2 illustrate a conventional evaporative cooler 10 comprising a 
housing 11, evaporator pads or assemblies 12 formed of a porous media, a 
fan or blower 13, its shaft 14 coupled by means of a pulley 15 and a belt 
16 to an electric motor 17, a water pump 18, a water distribution system 
including a "spider" 19 and troughs 21, and a water reservoir or sump 22. 
Housing 11 has four vertical walls 23 of approximately equal dimensions, a 
flat horizontal top 24 and an air delivery port 30 at the bottom of unit 
10. The four walls 23 are louvered as shown for the passage of air. 
Pump 18 supplies water from sump 22 through a rubber or plastic hose 25 to 
a central manifold 26 of spider 19. From manifold 26, the water flows 
through legs 27 of spider 19 into distribution troughs 28 located along 
the top edges of pads 12. From troughs 28, the water drips through 
distributor openings or holes uniformly positioned or disposed along the 
bottoms of troughs 28 onto pads 12. The water dropping on the tops of pads 
12 seeps downwardly through pads 12 keeping them moist. Pads 12 are 
typically made of excelsior or of a synthetic water absorbent material 
capable of holding moisture. Excess water drains from the bottom of pads 
12 to sump 22. The water level in sump 22 is maintained by a water supply 
line and a float controlled valve, not shown in the drawings. 
Blower 13, typically a centrifugal or squirrel cage type, draws outside or 
ambient air 29 through the air inlet side of pads 12 and delivers air 
through its outlet side through port 30 to the dwelling or other structure 
to be cooled. As the air passes through pads 12, it gives up heat to the 
evaporating water held by the pads so that air 31 delivered at port 30 is 
considerably cooler than outside air 29. 
In a given installation, the performance of the evaporative cooler and the 
demands placed upon it vary with the season. During periods of high 
temperature and low humidity, the cooling demand is high, but the cooling 
efficiency is also high because of the low humidity which aids 
evaporation. When both temperature and humidity are high, the demand is 
high and the efficiency is low. At such times, it is frequently found that 
the evaporative cooler as installed is not adequate to meet the demand. 
The auxiliary cooler shell or precooler of the present invention provides 
a means for enhancing the performance of the evaporative cooler so that 
more effective cooling can be obtained throughout the cooling season. 
The auxiliary cooler shell 32, as shown in FIG. 3, comprises a shell, 
jacket or frame 33, a porous media, such as evaporator pads 34, a spider 
35, water distribution troughs 36 and drain troughs 37. 
The arrangement of the components of shell 32 is similar to the arrangement 
of the corresponding parts in the conventional cooler 10, as described 
above. In a downdraft version of the shell, there are four pads 34, one 
inside each of the four louvered walls 38 of frame 33. Spider 35 receives 
water from pump 18 located in the primary evaporative cooler 10 and 
delivers it to the distribution troughs 36. Water from troughs 36 passes 
through uniformly distributed holes in the base of troughs 36 and seeps 
downwardly by gravitation through evaporator pads 34. The excess water is 
collected at the bottoms of pads 34 by collection trough 37, flowing from 
trough 37 through an overflow spout 39 back into sump 22 of evaporative 
cooler 10. 
Sliding plates or baffles 40 are provided at the bottom of frame 33 about 
its periphery for use in sealing against air leakage when shell 32 is 
installed over an evaporative cooler, thereby restricting the inflow of 
ambient air to said media before reaching the air inlets of the pad 
assemblies of the associated evaporative cooler. Plates 40 are slidably 
mounted to permit movement in the direction of the arrows 41 as shown in 
FIG. 3. 
As shown in FIG. 5, spider 35 is surrounded by a thermally insulating 
urethane foam pad 42 which aids in securing spider 35 to the underside of 
top member 43 of frame 33 and reduces heat flow into the top of shell 32 
on hot sunny days. 
When shell 32 is installed over a conventional cooler 10, as shown in FIGS. 
4 and 6, the four walls 38 of frame 33 surround the corresponding four 
walls of cooler 10 and the underside of urethane pad 42 rests upon top 24 
of cooler 10. The plates 40 at the base of shell 32 are moved inwardly 
against the sides of port 30 or against the sides of the frame of cooler 
10 to seal off the space between shell 32 and cooler 10 so that air flow 
from outside shell 32 can pass only through louvered walls 38 of frame 33. 
As shown in FIG. 6, spider 19 of cooler 10 and spider 35 of shell 32 are in 
direct communication with each other for water flow and both are supplied 
by pump 18 of cooler 10. In an actual installation, this connection is not 
made as shown in FIG. 6. For convenience a rubber or plastic tube is 
connected between spider 35 and tube 44 of FIG. 6 that carries water from 
pump 18 to spider 19. A commercially available "Y" or "T" fitting is 
employed for this purpose. 
Also, as shown in FIG. 6, spout 39 fed by trough 37 drains through a rubber 
tube 45 or other means into sump 22 of cooler 10. 
The operation of the enhanced evaporative cooling system comprising shell 
32 installed over cooler 10 occurs as follows: 
Water from pump 18 of cooler 10 flows to spiders 19 and 35 of cooler 10 and 
shell 32, respectively. Spider 19 supplies water to pads 12 of cooler 10 
and spider 35 supplies water to pads 34 of shell 32. Excess water from 
pads 12 and 34 is returned to pump 18 by way of sump 22. Blower 13 of 
cooler 10 draws air 29 from outside shell 32, the air 29 passing first 
through pads 34, and then through pads 12 of shell 32 and cooler 10, 
respectively. The air is cooled by evaporation of water at pads 34 and 12 
and then passes through blower 13 and port 30 into the dwelling that is 
being cooled. The increased exposure of the air due to the double set of 
evaporator pads through which the air is passed results in an increased 
level of evaporation, and a higher level of cooling efficiency is 
accordingly obtained so that effective cooling is obtained under the more 
severe climatic conditions. Under less severe conditions, adequate cooling 
is obtained at reduced air flow so that a lower blower speed may be 
employed to reduce cooling costs when such conditions prevail. 
A simple and inexpensive means is thus provided for the enhancement of an 
evaporative cooling system in accordance with the stated objects of the 
invention, and although but a single embodiment of the invention has been 
illustrated and described, it will be apparent to those skilled in the art 
that various changes and modifications may be made therein, as for 
example, the adaptation of the invention for use with a side-draft cooler, 
without departing from the spirit of the invention or from the scope of 
the appended claims.