U.S. patent application number 09/861551 was filed with the patent office on 2002-09-12 for condensate overflow safety switch.
Invention is credited to Brannick, Mark Thomas, Oakner Brannick, Donna Ellen, Oakner, Stuart Peter.
Application Number | 20020124582 09/861551 |
Document ID | / |
Family ID | 25174663 |
Filed Date | 2002-09-12 |
United States Patent
Application |
20020124582 |
Kind Code |
A1 |
Oakner, Stuart Peter ; et
al. |
September 12, 2002 |
CONDENSATE OVERFLOW SAFETY SWITCH
Abstract
A condensate overflow safety switch that can be used with an air
handling system is disclosed. The air-cooling system includes a
drain pan for collecting liquid condensed on the evaporator coils.
The drain pan is fluidwise connected to the safety switch that is
in turn electrically connected to a circuit of the air handling
system. To reduce the probability of an overflow from the drain pan
arising from an occlusion to water liquid draining from the drain
pan, an annular float is mounted about a tube in which is sealed a
reed switch electrically connected to a circuit of the air handling
system or to an alarm circuit. The float containing an annular
magnet ascends or descends based on the level of water liquid
within the structure. If a predetermined level of condensate liquid
within the safety switch tubular structure exists, the float will
have ascended such that the magnetic field of the annular magnet
will cause a reed switch to open in the case of the air handling
circuit, or to close in the case of an alarm circuit. Upon removal
of the drainage occlusion, the water liquid level within the
tubular structure will decrease below the predetermined level
thereby causing the float to descend and the reed switch contacts
to engage or to disengage, thereby rendering the circuit of the air
handling system operative or alarm circuit inoperative,
respectively. The disclosed condensate safety switch with its
tubular structure, either T-shaped or L-shaped; is compact and easy
to install, can be installed at any slope from horizontal to
vertical and, by virtue of its sealed electrical components, is of
heightened reliability in warning of drain line occlusions and/or
preventing drain pan overflows.
Inventors: |
Oakner, Stuart Peter; (Boca
Raton, FL) ; Brannick, Mark Thomas; (Boca Raton,
FL) ; Oakner Brannick, Donna Ellen; (Boca Raton,
FL) |
Correspondence
Address: |
Andrew F. Reish
DAVID, BRODY & DONDERSHINE, LLP
Suite 100
12200 SUNRISE VALLEY DRIVE
RESTON
VA
20191
US
|
Family ID: |
25174663 |
Appl. No.: |
09/861551 |
Filed: |
May 22, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09861551 |
May 22, 2001 |
|
|
|
09798951 |
Mar 6, 2001 |
|
|
|
Current U.S.
Class: |
62/150 ;
62/285 |
Current CPC
Class: |
H01H 36/02 20130101;
G01F 23/74 20130101; F25D 21/14 20130101; F24F 2140/30 20180101;
F24F 13/222 20130101 |
Class at
Publication: |
62/150 ;
62/285 |
International
Class: |
F25D 021/00; F25D
021/14 |
Claims
What is claimed is:
1. An air-cooling system comprising: means for cooling air; at
least one of a first circuit connected to means for controlling
supply of power to said means for cooling air or a second circuit
connected to an alarm circuit; air handling means for cooling warm
air, said air handling means having heat exchanger coils for
containing a cold material for cooling the warm air; a drain pan
for receiving condensate liquid formed on said exchanger coils;
said drain pan having at least one outlet; and tube means fluidwise
connected to said at least one outlet for conveying liquid away
from said drain pan, said tube means including: a safety switch
device having a tubular structure, said tubular structure having a
plurality of open ends, a first open end of said plurality of open
ends being fluidwise connected to one of said at least one outlet,
and an overflow switch assembly having a magnetically driven reed
switch, said reed switch including sealed contacts, each of said
contacts being electrically connected by at least one wire to one
of said first circuit and said second circuit, wherein said
overflow switch assembly is mounted, within a second open end of
said plurality of open ends.
2. The system according to claim 1, wherein said overflow switch
assembly further includes: a mounting cap for mounting said reed
switch within said second open end, said mounting cap having an
outer face, an inner face and central aperture therebetween; a
hollow tube having a closed first end portion, an open second end
portion, and an outer surface extending therebetween, said hollow
tube being disposed through said central aperture, a stop means
affixed to said closed end portion, and sealing means for sealingly
closing said open second portion; attachment means for adjustably
attaching said open end portion adjacent to said outer face, and a
buoyant annular float body moveable along said outer surface
between said stop means and a predetermined level toward said inner
face, said float having an annular magnet disposed therein for
magnetically driving said contacts, wherein said reed switch is
sealingly enclosed by said sealing means within said hollow tube
with said wires extending through said sealing means.
3. The system according to claim 2, wherein said annular float body
has a first face end and a second face end, and said annular magnet
is disposed closer to said first face end than said second face
end.
4. The system according to claim 3, wherein said contacts are
biased to closed, said contacts are electrically connected to said
first circuit, and said first face end faces away from said inner
face for floating upon the condensate liquid within said tubular
structure and for movement to the predetermined level upon a rise
in the level of the condensate liquid, whereby rising condensate
liquid within said tubular structure causes said annular float body
to rise toward the predetermined level.
5. The system according to claim 3, wherein said contacts are
biased to closed, said contacts are electrically connected to said
second circuit, and said second face end faces away from said inner
face for floating upon the condensate liquid within said tubular
structure and for movement to the predetermined level upon a rise
in the level of the condensate liquid, whereby rising condensate
liquid within said tubular structure causes said annular float body
to rise toward the predetermined level.
6. The system according to claim 4, wherein the predetermined level
is the level whereat said annular magnet drives said contacts to
separate.
7. The system according to claim 5, wherein the predetermined level
is the level whereat said annular magnet drives said contacts to
close.
8. The system according to claim 1, wherein said tubular structure
is one of a T-shaped structure or an L-shaped structure.
9. A condensate overflow safety switch device comprising: a tubular
structure for receiving and monitoring condensate liquid draining
from a drain pan, said structure having a plurality of open ends, a
first open end of said plurality of open ends being fluidwise
connected to the drain pan; an overflow switch assembly including a
magnetically driven reed switch, said reed switch having sealed
contacts mounted in a second open end of said plurality of open
ends, each of said contacts having at least one wire for electrical
connection to one of a first circuit for de-activating production
of the condensate liquid and a second circuit for activating an
alarm, wherein said overflow switch assembly is mounted within a
second open end of said plurality of open ends.
10. The switch device according to claim 9, wherein, wherein said
overflow switch assembly further includes: a mounting cap for
mounting said reed switch within said second open end, said
mounting cap having an outer face, an inner face and central
aperture therebetween; a hollow tube having a closed first end
portion, an open second end portion, and an outer surface extending
therebetween, said hollow tube being disposed through said central
aperture, a stop means affixed to said closed end portion, and
sealing means for sealingly closing said open second portion;
attachment means for adjustably attaching said open end portion
adjacent to said outer face, and a buoyant annular float body
moveable along said outer surface between said stop means and a
predetermined level toward said inner face, said float having an
annular magnet disposed therein for magnetically driving said
contacts, wherein said reed switch is sealingly enclosed by said
sealing means within said hollow tube with said wires extending
through said sealing means.
11. The switch device according to claim 10, wherein said annular
float body has a first face end and a second face end, and said
annular magnet is disposed closer to said first face end than said
second face end.
12. The switch device according to claim 11, wherein said contacts
are biased to closed, said contacts are for electrical connection
to said first circuit, and said first face end faces away from said
inner face for floating upon the condensate liquid within said
tubular structure and for movement to the predetermined level upon
a rise in the level of the condensate liquid, whereby rising
condensate liquid within said tubular structure causes said annular
float body to rise toward the predetermined level.
13. The switch device according to claim 11, wherein said contacts
are biased to closed, said contacts are for electrical connection
to said second circuit, and said second face end faces away from
said inner face for floating upon the condensate liquid within said
tubular structure and for movement to the predetermined level upon
a rise in the level of the condensate liquid, whereby rising
condensate liquid within said tubular structure causes said annular
float body to rise toward the predetermined level.
14. The system according to claim 12, wherein the predetermined
level is the level whereat said annular magnet drives said contacts
to separate.
15. The system according to claim 13, wherein the predetermined
level is the level whereat said annular magnet drives said contacts
to close.
16. The system according to claim 9, wherein said tubular structure
is one of a T-shaped structure or an L-shaped structure.
17. A method for preventing condensate liquid overflow from a drain
pan receiving condensate liquid from an air handling unit
comprising the steps of: installing a tube means fluidwise
connected to an outlet for conveying condensate liquid away from
the drain pan, said tube means including: a safety switch device
having a tubular structure, said tubular structure having a
plurality of open ends, a first open end of said plurality of open
ends being fluidwise connected to the outlet; and an overflow
switch assembly mounted within a second open end of said plurality
of open ends; said assembly including: a magnetically driven reed
switch, said reed switch including sealed contacts biased to
closed, each of said contacts having at least one wire for
electrical connection to a circuit connected to means for
controlling supply of power to the air handling unit; a mounting
cap for mounting said reed switch within said second open end, said
mounting cap having an outer face, an inner face and central
aperture therebetween; a hollow tube having a closed first end
portion, an open second end portion, an outer surface extending
therebetween, and a stop means affixed to said closed first end
portion, said hollow tube being disposed through said central
aperture, and sealing means for sealingly closing said open second
portion with the said reed switch within said hollow tube and said
wires extending therethrough; attachment means for adjustably
attaching said open end portion adjacent to said outer face; and a
buoyant annular float body moveable along said outer surface
between said stop means and a predetermined level toward said inner
face, said float body having a first face end and a second face end
and an annular magnet disposed therebetween for magnetically
driving said contacts, said annular magnet being disposed closer to
said first face end than said second face end, and electrically
connecting said wires into said circuit.
18. The method according to claim 17, wherein the tubular structure
is T-shaped and the installing step includes inclining the central
axis of said hollow tube at an angle between 0 and 45 degrees to
vertical.
19. The method according to claim 17, wherein the tubular structure
is L-shaped and the installing step includes inclining the central
axis of said hollow tube at an angle between 0 and 20 degrees to
vertical.
20. A method for alarming of potential condensate liquid overflow
from a drain pan receiving condensate liquid from an air handling
unit comprising the steps of: installing a tube means fluidwise
connected to an outlet for conveying condensate liquid away from
the drain pan, said tube means including: a safety switch device
having a tubular structure, said tubular structure having a
plurality of open ends, a first open end of said plurality of open
ends being fluidwise connected to the outlet, and an overflow
switch assembly mounted within a second open end of said plurality
of open ends, said assembly including: a magnetically driven reed
switch, said reed switch including sealed contacts biased to
closed, each of said contacts having at least one wire for
electrical connection to a circuit connected to means for signaling
an alarm; a mounting cap for mounting said reed switch within said
second open end, said mounting cap having an outer face, an inner
face and central aperture therebetween; a hollow tube having a
closed first end portion, an open second end portion, an outer
surface extending therebetween, and a stop means affixed to said
closed first end portion, said hollow tube being disposed through
said central aperture, and sealing means for sealingly closing said
open second portion with the said reed switch within said hollow
tube and said wires extending therethrough; attachment means for
adjustably attaching said open end portion adjacent to said outer
face; and a buoyant annular float body moveable along said outer
surface between said stop means and a predetermined level toward
said inner face, said float body having a first face end and a
second face end and an annular magnet disposed therebetween for
magnetically driving said contacts, said annular magnet being
disposed closer to said first face end than said second face end,
and electrically connecting said wires into said circuit.
21. The method according to claim 20, wherein the tubular structure
is T-shaped and the installing step includes inclining the central
axis of said hollow tube at an angle between 0 and 45 degrees to
vertical.
22. The method according to claim 21, wherein the tubular structure
is L-shaped and the installing step includes inclining the central
axis of said hollow tube at an angle between 0 and 20 degrees to
vertical.
23. A method for preventing condensate liquid overflow from a drain
pan receiving condensate liquid from an air handling unit
comprising the steps of: installing a tube means fluidwise
connected to an outlet for conveying condensate liquid away from
the drain pan, said tube means including: a safety switch device
having a T-shaped tubular structure, said tubular structure having
a first open end, a second open end and a third open end, said
first open end and said second open end being opposite one another,
and said third open end being fluidwise connected to the outlet;
and an overflow switch assembly mounted within a second open end of
said plurality of open ends; said assembly including: an electrical
switch, said switch having electrical contacts, each of said
contacts having at least one wire for electrical connection to a
circuit connected to means for controlling supply of power to the
air handling unit; a mounting cap for mounting said switch adjacent
said second open end, said mounting cap having an outer face, an
inner face and central aperture therebetween; a rod having a first
end portion and a second end portion, said rod being disposed
through said central aperture such that said first end portion
extends beyond said outer face; attachment means for attaching said
first end portion adjacent to said outer face; and a buoyant float
body suspended at said second end portion, said float body being
moveable to a predetermined level from said inner face; and
electrically connecting said wires into said circuit.
24. The method according to claim 23, wherein the installing step
includes mounting said tubular structure such that said second open
end is vertically above said first open end.
25. The method according to claim 24, wherein the installing step
further includes inclining said tubular structure such that the
central axis of said rod inclines at an angle between 0 and 45
degrees to vertical.
Description
[0001] The present application is a continuation-in-part of U.S.
patent application Ser. No. 09/798,951 filed Mar. 6, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to electrical condensate
overflow safety switches. It is particularly directed to a device
having an electrical float switch for de-activating air handling
units, namely, air conditioning and refrigeration units, and/or
activating an alarm signal. The activating/de-activating actions
occur in the event a condensate drain line occludes in order to
prevent or warn of potential drain pan overflows that could cause
water damage to a building structure. The present invention
provides an easy-to-install system either as original equipment at
the initial installation of the air-handling units or as a
retrofit.
[0004] 2. Descriptions of the Related Art
[0005] Many residential and commercial air conditioning and
refrigeration units employ an evaporator coil to dehumidify and
cool ambient air in dwellings, climate controlled storage spaces,
workspaces, and the like. The evaporator coil is frequently located
indoors, often above the occupied areas of the building that it
serves. Since the coil is colder than the air being conditioned, it
condenses water liquid continuously while in operation. This
condensate water liquid is typically collected in a drain pan,
usually positioned under the coil, with the drain pan having one or
more outlet ports for attaching a drainpipe for outflow of the
condensate. The condensate water liquid drains through one or more
of these outlets and generally through a drainpipe out of or away
from the building. The drain pan, pan outlets and drainpipe,
including any U-shaped trap, which may be provided to create a
fluid seal between the airs on opposite sides of the trap, often
become occluded by algae, mold, mildew, dirt, etc. This occlusion
may result in pan overflows that can cause water damage to building
ceilings, walls, flooring and associated building components, which
necessitate costly repairs.
[0006] In recognition of damages resulting from overflow of liquid
drain lines and containers, pre-existing efforts have been made to
alert users of those drain lines and containers of potential
blockage or overflow situations.
[0007] U.S. Pat. No. 4,393,128, to Young et al. discloses a sewage
back-up alarm unit for placement in an existing sewer line
connecting a residence to a sewage collection system. It discloses
electrical conductors extending into the interior of the connection
element for detection of the rise of sewage into the unit whereby
an alarm is emitted when the liquid rises to a level corresponding
to sufficient voltage to complete the circuit and sound an alarm
such that a human can initiate action to preclude sewage back up.
The alarm system relies not only on metal strips subject to coating
with sewage and corrosion from sewage contaminants which will
reduce the accuracy of readings for initiating the alarm, but
requires human intervention should a backup actually exist.
[0008] U.S. Pat. No. 4,937,559 to Meachum et al discloses an air
conditioner drain blockage alarm having a float switch within which
activates an alarm and a shut off circuit when a potential overflow
event is detected. FIG. 3 reflects a float having an upper face
contact 21 which upon upward movement by rising water liquid within
switch housing, connects a pair of housing contacts on the lower
face of the closed end of the switch housing, resulting in alarm
activation and air handling unit de-activation. The housing is
vented. The system does not recognize the ambient atmospheric as a
corrosion source for the housing contacts, which reduces the
reliability of the alarm and shut off.
[0009] U.S. Pat. No. 5,028,910 to Meachum et al discloses a drain
overflow alarm for a washing machine drain. The device discloses a
float disposed in a vertical drain line offset from the main
washing machine drain line connected to the sewer, the float moving
vertically upon liquid backup to interrupt the flow of electric
current to the washing machine. The upper surface of the float has
spaced float contacts that rise upward upon water back up to
contact with fixed contacts on the downward facing inner, causing
the interruption of the flow of electric current to the washing
machine. While alluding that the float may be provided with an
internal magnet so as to be able to act as part of a magnetic reed
switch, no other elements were described in the alternative. Thus,
as the system relies only on metal contacts subject to corrosion
from sewage gases and contaminants as well as moisture, the
combination of elements fails to recognize requirements of
reliability to insure preclusion of overflow.
[0010] U.S. Pat. No. 5,069,042 to Stuchlik discloses a cleanable
condensate U-shaped trap that can be used in the condensate
drainage tubing of an air-cooling system. The condensate trap is
designed so that any blockage existing in the trap can be easily
detected and removed; for example, using a flexible brush that can
be inserted through a U-shaped tube that forms part of the trap. A
mechanical switching mechanism, including a float, is disclosed in
a portion of the trap. The switching mechanism is arranged so that
when liquid collects in the trap due to a blockage in the trap, or
in the tubing located downstream of the trap; the float rises so as
to cause a mechanical switch to shut off the air-cooling system
and/or trigger an alarm. The metal linkage components and
electrical contacts are exposed to ambient air. The system does not
recognize the ambient atmospheric as a corrosion source for the
linkage and contacts, which reduces the reliability of the shut off
and the alarm.
[0011] U.S. Pat. No. 5,522,229 to Stuchlik discloses a blockade
detector in the drain line of an air cooling system, the detector
extending from a drain tube portion of the drain line into the air
handler drain pan, to determine the presence of liquid at a certain
level. A two prong liquid sensor probe is located at least
partially in the drain tube, and includes a probe end that extends
from the drain tube inlet end into the drain pan, when attached to
the drain pan. The liquid sensor probe detects the undesired
accumulation of liquid in the drain pan caused by a blockage in the
drain pan, in the drain tube, or in any other portion of the
drainage tubing. A control circuit generates an output signal when
excess liquid is present at the probe end of the liquid sensor, so
as to sound an alarm and/or turn off the air-cooling device. The
drain tube is provided with an access port for a cleaning device to
clean the drain pan outlet, the drain tube, and a U-shaped trap.
The system relies on metal contacts exposed to contaminated liquid
fostering corrosion that will reduce the accuracy of readings for
initiating the alarm or interrupting the system.
[0012] U.S. Pat. No. 5,621,393 to Urich discloses a fill-level test
and measuring device that serves as an overfilling prevention means
for a liquids container, particularly to corrosive media
containers; the device allowing remote-controlled monitoring of its
operability by permitting lifting of the float without being
supported by buoyancy. The float slides upward on a slide tube,
either as a result of action by the individual monitor or due to
rise of liquid level. There appears to be no indication of
automatic intake cut-off upon reaching a certain predetermined fill
level.
[0013] U.S. Pat. No. 6,154,144 to Johnson discloses an automatic
shutoff overflow controller comprising a circuit which engages
between a source of power and a water liquid processing device; the
controller, sensing an undesirably high water liquid level in the
device, shutting off the device and producing an audible warning
that such condition exists.
OBJECT AND SUMMARY OF THE INVENTION
[0014] In order to design an effective condensate safety switch
device for preventing structural damage to building components from
condensate water liquid overflows; it is necessary to provide a
system and/or a safety switch that senses condensate drain line
occlusion and either 1) stops the generation of condensate liquid
until the cause of the drain occlusion can be remedied, or 2)
activates an alarm indicating the occurrence of such occlusion.
[0015] An object of the invention is creating a condensate overflow
safety switch that is characterized by simple mechanical and
electrical design, compactness, low manufacturing complexity, and
high operational reliability.
[0016] Another object of the present invention is to provide a
safety switch having compact switch means sealed from environmental
contamination.
[0017] A further object of the present invention is to affect, in
the situation where an occlusion has occurred in the drain line
fluidwise connected to the drain pan, an interruption to operation
of the air-cooling means; producing condensate in the drain pan, or
activating an audible, visual or electronic alarm indicating the
presence of such occlusion.
[0018] To achieve the foregoing and other objects, and to overcome
the limitations set forth above, a condensate overflow safety
switch is provided. The present invention includes a T-shaped or
L-shaped (right angle or curved) tubular structure, which can be
connected fluidwise to a drain pan. The tubular structure mounts a
reliable float switch to detect the existence of a predetermined
level of liquid therein, which correlates with the level of water
liquid in the drain pan. Presuming that the correlation
approximates 1:1 and that an occlusion exists such that the liquid
in the drain pan cannot drain, the predetermined level is set below
the lowest level at which liquid would overflow the low point of
the upper edge of the pan, or out of an orifice which was not
provided with a drain line.
[0019] The float switch comprises a hollow tube or rod containing a
reed switch sealed therein with wires extending though the seal,
the hollow tube being surrounded by an annular float body
containing an annular magnet disposed between the longitudinal
midpoint of the float body and one of the longitudinal ends of the
float body; the float body being mounted about the tube such that
it ascends to and descends from the predetermined level in response
to the liquid level in the tubular structure. The reed switch
includes contacts that are biased toward contact and can be
connected to an electrical circuit of the air handler electrical
control unit, preferably the thermostat electrical circuit, or to
an alarm circuit. The float body is mounted about the tube with the
magnet in the portion thereof facing toward the liquid and the reed
switch is connected to an electrical circuit of the air handler
electrical control unit. As the liquid causes it to ascend, as the
magnet becomes orthogonally adjacent to the reed switch contacts;
its magnetic field would cause the contacts to separate, which
would open the circuit rendering inoperative the system producing
the condensate collected in the drain pan. After the occlusion is
cleared and resolved, the condensate will drain from the drain pan
to reduce the liquid level in the drain pan and correspondingly
reduce the liquid level in the tubular structure. With the decrease
of the liquid in the tubular structure to a level below the
predetermined level; the float switch will descend and the reed
switch will close, allowing the system producing the condensate to
operate.
[0020] On the other hand, when the reed switch is connected to an
alarm circuit, the float body is mounted about the hollow tube with
the magnet in the portion thereof in close proximity to the reed
switch contacts, thereby causing the reed switch to open. As the
condensate causes the float body to ascend past the reed switch
until the condensate reaches a predetermined level, the magnetic
field has reduced influence on the reeds of the reed switch. As a
result, the reeds, which are biased to close, close thereby closing
an electrical alarm circuit to activate an alarm notifying of a
possible occlusion to condensate liquid draining from the drain
pan. After any occlusion is cleared and resolved, the level of the
liquid in the tubular structure will descend causing the float to
descend with the resultant opening of the contacts of the reed
switch thereby deactivating the alarm circuit.
[0021] The float switch is mounted within an opening of the tubular
structure via a mounting cap that can be removed from the structure
for maintenance and inspection. The hollow tube containing the reed
switch and mounting the float body with annular magnet therein can
be adjusted closer or farther from the mounting cap, enabling the
float body to be positioned at various depths within the tubular
structure. The inner and outer diameters of the openings of the
tubular structure may vary in size. The closure caps and mounting
cap of the tubular structure may vary in construction, shape and
materials; the materials varying from a plastic (opaque,
translucent or transparent), to metal. Likewise the size, shape,
and material of the tubular T-shaped body or L-shaped body may vary
similarly to those of the closure caps and mounting cap. In
conclusion, the switch can be positioned in the primary condensate
drain line, on the primary or any auxiliary drain line outlet on
the primary drain pan, on the auxiliary drain pan outlet (when
present), or in the auxiliary drain pan drain (when present).
[0022] The device of the T-shaped embodiment can be positioned at a
slope from vertical to horizontal, facilitating installation in
small spaces and drain lines that run at various angles. The
L-shaped embodiment may be small in size, thereby facilitating
positioning on outlets in small spaces and precludes the need for a
plug on auxiliary drain outlets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The invention will be described in detail with reference to
the following drawings in which like reference numerals refer to
like elements and wherein:
[0024] FIG. 1 is a diagrammatic view of an air-cooling system
incorporating the condensate overflow safety switch of the present
invention;
[0025] FIG. 2 is an exploded, isometric view of one embodiment of
the condensate overflow safety switch of the present invention;
[0026] FIG. 3 is an isometric view of the L-shaped tubular
structure of another embodiment of the condensate overflow safety
switch of the present invention;
[0027] FIGS. 4a-4c are isometric views of the caps for the open
ends of the tubular structure; and
[0028] FIGS. 5a-5b are schematic views of the overflow switch
mounted in the T-shaped and L-shaped tubular structure,
respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] FIG. 1 illustrates an air-cooling system including a
condensate overflow safety switch device 100 according to the
present invention. The cooling system includes air-cooling means
102, which can be, for example, an air conditioning unit or other
air-handling unit. The air-cooling means 102 is operatively
associated with an air handler means 104 that includes heat
exchange coils 106 which carry a cold material for cooling warm air
conveyed to the air handler means 104 through duct 108. Cooled air
is conveyed away from air handler means 104 through duct 110. As
the air is cooled, liquid in the air condenses and is removed from
the air to fall into a drain pan 112 from which it may outflow away
from air handler means 104 through a primary drain pan outlet 114
via device 100 to a drain line 116, or it may outflow through
secondary drain pan outlet 118. Air-cooling means 102 is controlled
by, for example, a thermostat 120 that is electrically connected to
air-cooling means 102 via a circuit 122. An embodiment of the
present invention provides overflow switch assembly 124 operatively
associated with device 100. Overflow switch assembly 124 opens
circuit 122 when liquid in device 100 rises to a predetermined
level due to clogging of device 100 and/or drain line 116. In this
manner, air cooling means 102 is rendered inoperative when device
100 and/or drain line 116 is clogged, to prevent the production of
any further condensation and thus prevent the overflow of liquid
and the damage associated therewith. Likewise, another embodiment
of the present invention comprises a device 100', which is attached
to the secondary outlet 118, having overflow switch assembly 124
which similarly opens circuit 1124 when liquid in device 100' rises
to a predetermined level to render air cooling means 102
inoperative. It is to be noted that device 100 and device 100' are
interchangeable by methods known to one skilled in the art. While
FIG. 1 shows the use of both device 100 and 101', either can be
removed with circuit 122 being associated with the remaining device
by methods known to one skilled in the art. Further, it is to be
noted that rather than overflow switch assembly 124 de-activating
circuit 122, each can alternatively activate an alarm circuit
123.
[0030] FIG. 2 shows a first embodiment of the condensate overflow
safety device 100. Device 100 includes a T-shaped tubular structure
1 having first, second and third open ends 2a, 2b, and 2c. The
first end 2a is attached to an outlet tubing 10 extending from
drain pan 112 so as to be in connection fluidwise with the drain
pan 112. Either of end 2b or end 2c receives an overflow switch
assembly 124.
[0031] The overflow switch assembly 124 has the following described
elements: A mounting cap 21 has an inner surface 22 and an outer
surface 23 with an aperture 24 therebetween. A hollow tube 25
having an open end portion 26 and a closed end portion 27 with a
stepped outer surface 28 extending therebetween. A reed switch 29
having longitudinally disposed electrical contacts and connecting
insulating wires 30 is disposed within the hollow tube 25. A
sealing material 31, for example plastic or epoxy, isolates and
disposes the reed switch 29 within the hollow tube 25, the wires 30
extending therethrough for connecting to circuit 122 or an alarm
circuit 123. The open end portion 26 is received into the aperture
24 for attachment to the mounting cap 21 by a depth attachment
means 31, in this case by a nut engageable to threads 32 on the
surface 28. (However, is within the scope of the invention that the
depth attachment means 31 may be comprised of any known means of
affixing the hollow tube 25 to the mounting cap 21.) An upper
arcuate stopper mechanism 33 is engaged onto the hollow tube inward
from the inner surface 22. And a removable arcuate stopper
mechanism 34 is engaged onto the surface 28 of the hollow tube 25,
adjacent the closed end portion 27. An annular float body 35 having
a first end face 36 and a second end face 37 is mounted for
slidable movement along the hollow tube 25 containing the reed
switch 29. Within the float body 35, an annular magnet 38 is
disposed closer to first end face 36 than to second end face 37.
When the wires 36 are connected to circuit 122, the float body is
mounted with the first end face 36 facing toward arcuate stopper
mechanism 34. When the wires 36 are connected to alarm circuit 123,
the float body 35 is mounted with the second end face 37 facing
toward stopper mechanism 34.
[0032] A closure cap 39 is insertable and attachable by known
means, for example, friction fit or adhesive, within any of the
first, second, and third open ends 2a, 2b, and 2c, which does not
otherwise receive drain tubing, drain line, drain outlet, or
mounting cap 21. The mounting cap 21 and the closure cap 39 may be
of similar design, though in its preferred embodiment, the counting
cap 21 has an aperture 24 therein, whereas closure cap 39 would not
necessarily have such an aperture.
[0033] FIG. 3 shows a second embodiment of the condensate overflow
safety switch 100'. Switch 100' includes an L-shaped tubular
structure 1' having first and second open ends 2a and 2b. The first
end 2a is attached to an outlet tubing 118 extending from drain pan
112 so as to be in connection fluidwise with the drain pan 112. The
overflow switch assembly 124 and mounting cap 21 are common to
those shown in the embodiment of FIG. 2 and, thus their description
is incorporated herein by reference.
[0034] FIGS. 4a, 4b, and 4c show three examples of the closure cap
39. FIG. 4a shows a cup-shaped cap 39 to fit within an open end of
the tubular structure 1. FIG. 4b shows a mounting cap 39 shaped to
fit over the lip of and surround an open end of the tubular
structure 1. FIG. 4c shows a mounting cap 39 designed to fit within
an open end of the tubular structure 1.
[0035] As to the above-described elements shown in FIGS. 2, 3, and
4a-4c, with the exception of the reed switch 29, wires 30, stopper
mechanism 33 and 34 and annular magnet 38, which normally require
metal content for optimizing performance, the elements can be made
of metal, plastic, PVC or other comparable material. However, of
course, the overall construction of the float body must insure
buoyancy thereof Regarding the plastic material, it can be
transparent, translucent or opaque.
[0036] As to the dimensions of the elements above-described and
shown in FIGS. 2, 3 and 4a-4c, they may vary as required by the
circumstances of the environment in which they are applied.
However, in usual circumstances, the T-shaped tubular structure 1
and the L-shaped tubular structure 1' may measure 3 to 4 inches in
length. The T-shaped tubular structure 1 is from 2 to 3 inches from
the open end 2b to the opposite bottom. The segments that form the
T-shaped body may vary in internal or external diameter, but are
generally from 1/2 to 3 inches in diameter. The inner and outer
surface of the segments that form the tubular body may vary in
shape to aid in engaging the float assembly and to affixing to the
switch mounting cap, to an end closure cap, to the drain line, or
to the drain pan outlet.
[0037] In operation, with respect to the embodiments of device 100
or device 100' attached in fluidwise connection to an outlet of the
drain pan 112, when either device or the drain line 116 clogs, the
condensate liquid in the drain pipe, drain line, or drain pan backs
up; causing a float body 35 inside either device 100 (T-shaped
body) or device 100' (L-shaped body) to ascend; causing either 1)
the reed switch 30 to open the circuit 122, preferably the
thermostat circuit, thereby shutting off the refrigerant
circulation in the air cooling means 102, retarding the generation
of additional condensate water liquid, and hindering overflow from
the drain pan 122, or 2) the reed switch 30 to close the circuit
123, thereby causing an alarm to signal the existence of a
potential overflow situation. Additionally, in use, when the
mounting cap 21 and assembly 124 are mounted on the device 100. the
device 100 can be inclined such that the central axis A of the
hollow tube 25 can be disposed at an angle .THETA. up to
substantially 45 degrees from the vertical while maintaining
continued operability (FIG. 5a). Likewise, when the mounting cap 21
and assembly 124 are mounted on device 100', the central axis A of
the hollow tube 25 can be disposed at an angle .THETA.' up to
substantially 20 degrees to the vertical while maintaining
continued operability (FIG. 5b).
[0038] In the invention being thus described it will be obvious
that the same may be varied in many ways. Such variations are not
to be regarded as the departure from the spirit and scope of the
invention, and all such modifications as would be obvious to one
skilled in the art; such as variations in dimension and shape,
intended to be included within the scope of the above
description.
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