Patent Application
20050138939
1. Field of Invention
The present invention relates to a condensate overflow prevention apparatus for use with an air cooling system, and in particular to a condensate overflow prevention apparatus that uses a pump.
2. Description of Related Art
An air cooling system, such as an air conditioner or a heat pump, typically has heat exchange coils that produce condensate as the system cools the air in a building. The condensate can cause damage to structures within the building, such as dry walls, ceilings, wooden supports, etc. Thus, the condensate is collected in a drain pan usually placed below the heat exchange coils, and is transported away through a drain line connected to the drain pan. Over a period of time, a blockage can occur in the drain pan or the drain line due to debris, algae, mold, etc. The blockage causes the condensate to accumulate in the drain pan, and eventually, overflows to cause damage to the building.
U.S. Pat. No. 5,069,042 discloses a condensate trap that includes a mechanical switch and a float. When the condensate accumulates in the trap due to a blockage, the float rises with the rising level of the condensate. Eventually, the float activates the mechanical switch to shut off the air cooling system to prevent further condensate from being produced by the system.
U.S. Pat. No. 5,522,229 discloses a drain tube that includes an inlet end for attaching to a drain pan, and an outlet end for transporting condensate out of the drain pan. The drain tube includes a sensor probe that extends from the drain tube inlet end and into the drain pan when attached to the drain pan. The sensor probe detects excess condensate in the drain pan due to a blockage. When the excess condensate is detected, the sensor probe triggers a control circuit that generates an output signal to sound an alarm and/or turn off the air cooling system.
U.S. Pat. No. 5,755,105 discloses a sensor apparatus having an inlet end which attaches to the drain pan. The sensor includes a pair of water contact points at the inlet end, and when fluid or water makes contact with the points, the points become conductive, closing a circuit between the contacts. A signal is generated and is transmitted to the air cooling system to shut off the system. The sensor apparatus includes a fluid high level indicator light, which glows when this event occurs.
U.S. Pat. No. 6,442,955 B1 discloses a condensate overflow safety switch included in a T- or L-shaped tubular structure which attaches to a drain pan. The switch is electrically connected to a circuit of an air cooling system, a power circuit or an alarm circuit. The switch has an annular float containing an annular magnet mounted about a tube in which a reed switch is sealed. The float moves up and down based on the level of the liquid within the tubular structure. Depending upon a predetermined level of liquid within the tubular structure, the float will move along the tube to open or close the reed switch to either shut off the air cooling system or to activate an alarm.
U.S. Pat. No. 5,323,620 discloses an air conditioner condensate sump pump controller that controls a pump for periodically pumping condensate out of a sump. The sump pump controller includes a lower positioned positive temperature co-efficient (PTC) resistor and a higher positioned PTC resistor in the sump. When the condensate reaches the level of the lower positioned PTC resistor, the pump is activated to pump the condensate out of the sump. However, if the condensate reaches the level of the higher positioned PTC resistor, this indicates a blockage within the conduit to the pump or malfunction in the pump itself. The sump pump controller then shuts down the air conditioner to prevent further formation of the condensate.
A known drain pan pump has an encapsulated pump and electronic circuitry within a plastic housing. The drain pan pump sits on a floor of a drain pan and is activated when water is present in the drain pan. The drain pan pump is deactivated when the water has been pumped away.
Most of the above described devices switch off the air cooling system and/or activate an alarm when a condensate level in the drain pan rises due to a blockage in the drain line or the drain pan. However, shutting down the air cooling system does not prevent the air cooling system from producing further condensate due to residual cold coolant remaining in the heat exchange coils. The condensate can continue to drip into the drain pan, and eventually, the rising condensate can overflow from the drain pan causing water damage even though the air cooling system has ceased operating and an alarm, if fitted, has been activated. Thus, it is highly desirable to evacuate any excess condensate as soon as possible before it can overflow, and cause property damage.
Accordingly, a condensate overflow prevention device according to aspects of the invention is attachable to a drainage system, and includes a fluid pump that pumps out any excess condensate in the drainage system before the condensate overflows and causes damage. A fluid level sensor senses a level of condensate, and if the condensate level exceeds a predetermined level, the fluid level sensor activates the fluid pump to pump out the excess condensate from the drainage system.
These and other features and advantages of the invention are described in, or are apparent from, the following description of various exemplary embodiments of the invention.
Various exemplary embodiments of the invention are described in detail with reference to the following figures wherein:
The drainage system 20 includes a drain pan 22, a drain line 24 and at least one condensate overflow prevention device 30. The drainage system 20 also may include a condensate trap 26. The condensate produced by the heat exchange coils 6 drips into the drain pan 22, which is placed below the heat exchange coils 6. The drain pan 22 is coupled to a drain line 24 which transports the condensate to a drain.
In one embodiment, the condensate overflow prevention device 30 is attached to an outlet of the drain pan 22. The condensate overflow prevention device 30 detects for an excess level of condensate in the drain pan 22. Usually, the condensate that drips into the drain pan 22 flows away into the drain line 24 connected to the drain pan 22. However, if a blockage occurs in the drain line 24, or in the drain pan 22 adjacent to the inlet of the drain line 24, for example, due to accumulation of debris, algae, mold, etc., the condensate starts to accumulate and fill the drain pan 22. When the condensate exceeds a predetermined level in the drain pan 22, the condensate overflow prevention device 30 is activated and pumps the condensate out of the drain pan 22 and into another drain line 28, for example. In this manner, the condensate is prevented from overflowing out of the drain pan 22.
The condensate overflow prevention device 30 need not necessarily be attached to the drain pan 22. For example, the condensate overflow prevention device 30 can be attached to the drain line 24 or to the condensate trap 26, as shown in
It is preferable to attach the condensate overflow prevention device 30 to the drain pan 22 because it will be effective in dealing with blockages that occur anywhere in the drainage system (i.e., the device 30 may not detect a blockage at the inlet to the drain line 24 if the device 30 is located downstream of the blockage, e.g., in the trap 26). Since most drain pans 22 have a primary outlet and a secondary outlet, the overflow prevention device 30 can be attached to the secondary outlet when the drain line 24 is attached to the primary outlet.
The hollow body 42 includes an inlet 52 which protrudes from the hollow body 42 and is attachable to a part of the condensate drain system such as a drain pan, a drain line, a condensate trap, etc. For illustration purposes, the system is coupled to a drain pan 80. The inlet 52 is threaded to mate with an outlet 82 of the drain pan 80, which also is threaded. In other embodiments, the inlet 52 of the hollow body 42 and the outlet 82 of the drain pan 80 are not threaded. For example, the inlet 52 can be adapted to snap fit with the outlet 82 of the drain pan 80. In another example, the surface of the inlet 52 may be smooth or roughened, glued and slip fitted to the outlet 82 of the drain pan 80. Various methods of attaching the inlet 52 to the outlet 82 of the drain pan 80 can be contemplated by those skilled in the art.
The float 44 is disposed within the hollow body 42 and is connected to a switch 46, which is external to the hollow body 42, via a shaft 54. However, the switch 46 need not necessarily be external to the hollow body 42 and in other embodiments, the switch 46 is disposed within the hollow body 42. The float 44 can ascend and descend (i.e., move up and down) within the hollow body 42 such that as the condensate flows from the drain pan 80 and into the hollow body 42 through the inlet 52, the float 44 elevates with the level of condensate in the hollow body 42. As the float 44 elevates, the float 44 urges the shaft 54 towards the switch 46, and when the float 44 elevates to a predetermined level, the shaft 54 has moved sufficiently to activate the switch 46. The float 44 may be suspended initially at a fixed position, thereby the predetermined level in which the float 44 activates the switch 46 may be fixed or the initial position of the float 44 may be adjustable such that the installer can set the desired condensate level which would activate the switch 46.
The switch 46 is electrically coupled to the pump 48 which, in turn, is in fluid communication with the interior of the hollow body 42 via a tube 56. The tube 56 may be made of plastic, metal, etc. When the switch 46 is activated, the switch 46 activates the pump 48 to pump the condensate out of the hollow body 42 and into a drain line 58 in fluid communication with the pump 48. The pump 48 will continue to pump the fluid out of the hollow body 42 until the float 44 descends to a lower level that deactivates the switch 46 or the pump 48 is shut off. For example, the pump 48 may be fitted with a time delay relay 62 or a secondary sensor 64 or a combination of both to ensure that the pump 48 does not continue to operate after the condensate level has receded.
An annunciator 66, such as a warning light and/or an audio alarm, etc., may be connected to the switch 46 by electrical wires or the annunciator 66 may be wirelessly thereto. When the switch 46 is activated by the float 44, the switch 46 activates the annunciator 66 to alert the owner that excess condensate has accumulated in the drain pan 80.
The hollow body 42 may further include an outlet 68 which is covered by a cap 72. When the cap 72 is removed, additional drain line or a pump may be connected to the hollow body to expedite the transport of the condensate away from the hollow body 42. Alternatively, the outlet 68 may be used to access the interior of the hollow body 42 and if necessary, a brush may be used to clean the interior of the hollow body 42. In various embodiments, the hollow body 42 may further include a removable top plate 74 holding the switch 46 and the pump 48.
As shown in
When the condensate level in the drain pan 210 rises due to a blockage, and makes contact with the probes or electrodes 204, the probes or electrodes 204 conduct electricity, and activate the pump 104. The pump 104 operates to pump the condensate out of the drain pan 210 through the tube 202 and into a drain line 106 in fluid communication with the pump 104. By extending the integrated probe/tube 200 into the drain pan 210, excess condensate in the drain pan 210 can be drained out even though the drain pan outlet 212 to which the condensate overflow prevention device 100 is attached is blocked with debris, algae, etc. Additionally, an advantage of sensing the condensate level inside the drain pan 210 is provided rather than sensing the condensate outside of the drain pan 210. The condensate overflow prevention device 100 may further include an outlet 112 which is covered by a cap 114.
Various embodiments of the condensate overflow prevention device have been described above. In various embodiments, the condensate overflow prevention device can be mounted in a primary drain pan, as an integral part of the drain pan or as a retrofitted component after installation. In various embodiments, the condensate overflow prevention device can be fitted in the primary or secondary drain outlet of the primary drain pan inside an air cooling system or to a condensate trap, which is normally attached to the primary drain outlet of the drain pan, either in proximity to or remote from the air cooling system.
It should be appreciated that the body of the condensate overflow prevention device is not limited to a tubular structure or an elbow-shaped structure. For example, as shown in
In various embodiments, the switch can be mechanical, and can be a single or multiple electronic probe or sensor, reed type, ultrasonic, optical, light fiber, pneumatic or can use any other known switching method, or any combination of the above, all of which can be capable of single or multiple pole switching for the purpose of carrying out simultaneous multi-switching operations without the necessity of any extra relays.
In various embodiments, the pump can be directly mounted on a body of the condensate overflow prevention device so that the pump actually drains directly from the body itself, or the pump can be connected via a flexible tube to an outlet on the body. The pump may be positioned on any part of the surface of the body of the condensate overflow prevention device, which provides for a desirable drain of the body. The pump also can be connected via a flexible tube to a specially placed inlet inside a drain pan which can be integrated into the drain pan structure, or the pump can be retrofitted to the drain pan after installation of the air cooling system. The pump can be externally mounted onto the condensate overflow prevention device or the pump can be clamped to a drain line or the pump can be attached to a primary or secondary drain pan as an integral part or as a retrofit.
The pump may operate on a battery, a 6 volt, a 12 volt, a 24 volt, a 120 volt, a 220 volt, or any other voltage AC or DC, which may prove to be practical, for example, for the purpose of connecting into an electrical building monitoring system or meeting current or future building codes.
In various embodiments, the condensate overflow prevention device includes an optional integral warning lamp and/or audible alarm to alert service personnel or owners on a local level that the high condensate level has occurred.
In various embodiments, the annunciator can also communicate directly with the air cooling system and/or an external alarm by means of wiring, wireless RF frequency, infrared, ultraviolet, ultrasonic or any of the known communication technology or any combination of the above.
While the invention has been described with reference to preferred embodiments thereof, it is to be understood that the invention is not limited to the preferred embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the preferred embodiments are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single light emitting element, are also within the spirit and scope of the invention.
