Defrost heater support

An air cooler having coolant tubes, a drain, a pair of coolant tube supports and a defroster for preventing condensate in the drain from freezing. The coolant tube supports include a vertical plate provided with a pair of horizontally spaced notches for supporting the defroster. The notches open to the lower edge of the plate and converge towards one another.

BACKGROUND OF THE INVENTION 
This invention relates to air coolers and, in particular, to low profile 
unit coolers utilizing refrigeration cooling. 
Low profile unit coolers are designed to cool a variety of spaces such as 
walk-in coolers, beverage boxes, meat cutting and storage rooms, and 
produce storage areas. The coolers have been widely used due to their high 
output and compact size. Typically, the coolers are supported in the upper 
part of a room and have a short side profile so that floor space is not 
sacrificed. 
The coolers incorporate an elongate, continuous coil which is secured at 
either end by a support member. The support member typically includes a 
vertical plate containing pairs of holes through which the tubes of the 
coil extend. The coils are formed by inserting the open ends of U-shaped 
tubes through the pairs of holes in the vertical plates and by connecting 
these open ends to one another with short U-shaped lengths of tubing. 
A number of thin rectangular heat exchange fins containing holes which 
correspond to those of the end support members are generally fitted over 
the lengths of tubing before the tubes are connected. The fins are equally 
spaced along the tubes in order to facilitate the exchange of heat between 
the coils and the surrounding air. Although the spacing of the fins varies 
depending on the expected use of the cooler, the fins typically are spaced 
between 1/4" and 1/8" apart. 
The units are enclosed by elongate, box-shaped, rustproof outer housings 
and include one or more electrical fans which circulate the cooled air. 
When a unit is operating, condensation has a tendency to form on the heat 
exchange fins and the refrigeration coil. If ice forms on the coil and 
fins, defroster heat is provided periodically, causing the frozen 
condensate to melt. A drainage pan secured to the base of the cooler 
housing catches this condensate as it drips from the fins and the coil. To 
prevent the condensate from freezing and plugging the pan's drain, the 
coolers are provided with either electric or gas drainage pan defrosters. 
The electric defrosters are usually simple U-shaped resistance heaters 
which are connected by wires to the electrical circuit box of the cooler 
unit. These resistance heaters are typically secured to the drainage pan 
by means of brackets. Unfortunately, the use of brackets adds to the 
overall cost of the unit both in terms of materials and labor. The 
materials costs increase due to the cost of the brackets themselves and 
the labor costs increase due to the time required to secure the brackets 
to the drainage pan. 
The brackets also pose a potential sanitation problem. One possibility is 
that the brackets themselves will contaminate the unit. Additionally, 
because the brackets have a tendency to trap sediment and make it 
difficult to properly clean the drainage pan, the brackets may accentuate 
the possibility of contamination due to other causes. 
The use of brackets also leads to other maintenance problems. Specifically, 
the most convenient means of repairing or maintaining the internal 
components of the cooler is to remove the drainage pan. Unfortunately, the 
drainage pan can not be completely removed from the cooler because the 
electrical connections between the control box and the resistance heater 
are too short. As a result, maintenance and repair work on the internal 
components of the cooler is less convenient and more time consuming. 
One method of avoiding some of the drawbacks inherent in bracketing a 
resistance heater to a cooler's drainage pan is to suspend the resistance 
heater from the refrigerator coil by wires. This involves the relatively 
difficult task of wrapping one end of the wires between the narrowly 
spaced heat exchange fins and around the tubes of the refrigeration coil, 
and wrapping the other end of the wires around the resistance heater. This 
procedure has proved unsatisfactory due to the time and effort required to 
perform it. 
Cooler units can also be provided with gas heat defrosters, rather than 
electric defrosters. The gas defrosters are typically U-shaped tubes 
containing hot gas. Commonly, brackets are used to suspend the gas filled 
tubes from the cooler's end support units. 
As with the case of the electrical defroster, the use of brackets to secure 
the defroster adds to the overall cost of the cooler both in terms of 
materials and labor. 
Thus, there is a need for a new and improved cooler in which cooler 
drainage pan defrosters can be more easily and efficiently secured. 
SUMMARY OF THE INVENTION 
The invention comprises an air cooler including coolant tubes mounted on 
supports having notches for supporting a defroster for preventing 
condensate in an adjacent drain from freezing. Thus, the defroster is 
easily installed and supported by the coolant tube supports rather than 
the drain pan. 
Advantageously, the supports are also provided with a larger pocket near 
the mouth of each of the notches for receiving and retaining gas 
defrosters, and the inner notch is sized to receive an electric defroster. 
With these mounting approaches, the drainage pan can be conveniently moved 
and cleaned without interference from the defrosters.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, there is shown a low profile unit cooler 1 having an 
elongate, box-shaped, rust-proof outer housing 3 which includes a top, a 
front wall and two side walls. The rear of the housing is open to provide 
an air inlet for the cooler. A series of brackets 5 are used to mount the 
housing 3 to a mounting surface 7. Two generally cylindrical, screened fan 
ducts 9 house a pair of fans 11 which circulate air through the cooler. 
A generally rectangular drainage pan 13 is removably secured to the bottom 
of the housing 3. Advantageously, the drainage pan has four short 
sidewalls 15 and a downwardly inwardly sloping bottom panel 17. Located at 
the lowest point of the drainage pan 13 is a cylindrical opening or drain 
19. 
Referring now to FIG. 2, a series of coolant tubes 21 within the housing 3 
are supported by a pair of coolant tube supports 23. The tubes 21 are 
interconnected to form a continuous coil. The coolant tube supports 23 
include a vertical plate 25 containing pairs of holes through which the 
coolant tubes extend and two vertical outer flanges 27. Numerous thin, 
vertical, rectangular heat exchange fins 29, containing holes 
corresponding to those of the coolant tube supports 23, are equally spaced 
along the coolant tubes between the two supports 23. 
Referring still to FIG. 2, an elongate, generally U-shaped electrical 
resistance heater or defroster 31 is secured to each of the supports 23 
proximate the drainage pan 13. As best seen in FIG. 3, the defroster 31 
consists of an electrically conductive resistance heating core 33 encased 
within a stainless steel tube 35 which is electrically insulated from the 
core 33 by a layer of asbestos powder. When electricity flows through the 
defroster core 33 the defroster 31 heats the drainage pan 13, thereby 
preventing the condensate therein from freezing and plugging the drain 19. 
The defroster 31 is supported at each end within a pair of horizontally 
spaced notches 37 formed in the lower portion of each of the support 
plates 25. As best seen in FIG. 4, the notches 37 converge upwardly at an 
angle about 45.degree. from the horizontal. The notches include an 
internal channel 39 opening to an outer pocket 41. The internal channels 
39 have parallel sides and a semi-circular end. Advantageously, the 
notches 37 are positioned so that the distance between the ends of their 
respective internal channels 39 is equivalent to the distance between the 
open ends of the U-shaped defroster 31. At the mouth of each internal 
channel 39 is a larger outer pocket 41 which forms a 3/4 circle and which 
has an entrance at the lower edge of the plates 25 of the supports 23. 
The defroster 31 can be easily secured to the supports 23 by bending its 
open ends outward so that each leg fits through the mouth of the outer 
pockets 41 and can be slid into the internal channels 39 of the notches 
37. As shown in FIG. 3, the defroster is advantageously provided with 
means for connecting the open ends of the defroster, such as a wire 43, to 
securely retain the legs of the defroster 31 within the notches so that 
the defroster is supported by the supports 23. 
Referring now to FIG. 4, the pockets 41 are adapted to receive and secure a 
gas defroster 45. The entry edges of the outer pocket 41 can be bent away 
from the mouth with pliers to permit the entry of the defroster 45 into 
the outer pocket 41. The pliers can then be used again to bend the edges 
of the outer pocket back to their original position, thereby securely 
retaining the gas defroster 45 in close proximity to the drainage pan. 
Thus, there is provided a cooler in which drainage pan defrosters can be 
more efficiently secured and supported. The present invention provides for 
the quick and easy installation of either gas or electric defrosters 
without interference to the drainage pan, while yet providing effective 
defrosting.