Abstract:
An air conditioning system condensate collection pan or water leak containment pan electrical control switch includes a housing or frame for supporting a switch unit which includes an elongated actuator arm. The housing includes a slot disposed adjacent a distal end of the actuator arm for receiving a water soluble tablet engageable with the actuator arm to bias the arm into a predetermined position of the switch. Abnormal accumulation of condensate or leaking water dissolves the tablet and allows the actuator arm to move to a position to effect actuation of the switch. The switch may be connected to a control unit, a thermostat and/or to an alarm generator including a self-contained unit having battery powered audio and/or visual alarm devices, an on-off switch and a circuit test switch.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of provisional application No. 60/802,675, filed: May 23, 2006. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Several developments have taken place with regard to providing a control switch and/or an alarm circuit for detecting abnormal levels of water in air conditioning unit condensate collection pans and water leak containment pans for hot water heaters and the like. 
         [0003]    However, there has been a continuing need for improvements in such devices including the provision of a device which may utilize a tablet which is readily dissolvable in water, and a control switch device which may be easily mounted in a condensate pan for an air conditioning cooling coil or a water containment pan for a hot water heater or the like. In particular, there has been a need for a control switch which can utilize a biocide composition tablet, such as of a type used in air conditioning condensate pans to minimize the accumulation of algae in the pan or an associated drain conduit, for example. 
         [0004]    There has also been a need for a control switch device which will provide a signal to a thermostat or the like, and/or automatically disable a cooling mode of operation of an air conditioning system. Still further, there has been a need for a control switch which will provide an audible as well as a visual signal in the event of accumulation of abnormal amounts of water in a condensate collection pan or a water leak containment pan and which device may be periodically tested for operability and may be easily retrofitted to existing installations of air conditioning equipment, hot water heaters and similar equipment. 
         [0005]    It is to the above-mentioned ends, as well as to provide other advantages in condensate pan and water leak containment pan control devices, that the present invention has been developed. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides an improved control switch for providing a control or alarm signal as a result of abnormal levels of condensate collecting in an air conditioning system condensate collection pan or a water containment pan for apparatus such as hot water heaters and the like. 
         [0007]    In accordance with one aspect of the present invention a water leak control switch is provided which includes a corrosion resistant housing or support structure which is adapted to utilize and support a water soluble tablet, such as a biocide composition tablet used in air conditioning condensate pans to minimize algae growth or the like. The control switch is easily mountable within a condensate collection pan or a water leak containment pan wherein the electrical components of the switch are not immersed in liquid but a switch actuator is engageable with a water soluble tablet or the like which is conveniently mounted for replacement and is operable to be dissolved readily if an accumulation of condensate, for example, reaches a predetermined level. The water soluble tablet support structure is conveniently arranged for placement of the tablet therein and the housing or support structure is configured to minimize the tablet inadvertently falling out of its working position. 
         [0008]    In accordance with a further aspect of the present invention, there is provided a water leak control switch in combination with an alarm unit which is self-contained and may be mounted adjacent the control switch but in a position to be readily accessible to determine if an alarm signal is being provided and to test the operability of a control circuit. The alarm unit may be battery powered and include an on-off switch, audible as well as visual alarm devices, a test switch and compact construction to provide for economical production and ease of installation. 
         [0009]    Those skilled in the art will further appreciate the above-mentioned advantages and superior features of the invention together with other important aspects thereof upon reading the detailed description which follows in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a side elevation of a water leak or water level alarm and control switch in accordance with the invention shown mounted within a condensate collection or water leak containment pan; 
           [0011]      FIG. 2  is a front elevation of the switch shown in  FIG. 1 ; 
           [0012]      FIG. 3  is a bottom plan view of the switch shown in  FIGS. 1 and 2 ; 
           [0013]      FIG. 4  is a schematic diagram of a control or alarm unit for providing a control or alarm signal generated by actuation of the switch of the present invention; and 
           [0014]      FIG. 5  is a schematic diagram of an air conditioning system including an alternate embodiment of a control switch in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    In the description which follows like elements are marked throughout the specification and drawing with the same reference numerals, respectively. The drawing figures are not necessarily to scale and certain features may be shown exaggerated in scale or in schematic form in the interest of clarity and conciseness. 
         [0016]    Referring to  FIG. 1 , there is illustrated a portion of a condensate collection pan or water leak containment pan, generally designated by the numeral  10 , having a bottom wall  11  and a side wall  12 .  FIG. 1  illustrates a control or alarm switch in accordance with the invention and generally designated by the numeral  14 . The switch  14  is preferably characterized by a corrosion resistant non-buoyant support housing  16  including a base  18  having a generally planar first part  20  and suitably secured to sidewall  12  or just allowed to rest on bottom wall  11  in the position shown. Support housing  16  includes opposed flanges  22  and  24 , see  FIGS. 2 and 3  also which are joined by an arcuate part  26  having opposed legs  28  and  30  defining a receptacle characterized as a slot  32  which intersects arcuate part  26  as well as the legs  28  and  30 . Slot  32  preferably extends at an acute angle with respect to the plane of base part  20  and the bottom wall  11  of pan  10 , as shown particularly in  FIGS. 1 and 2 . 
         [0017]    Control switch  14  includes a switch unit  34  suitably mounted on part  20  of housing  16  and disposed well above an expected liquid level  35 , see  FIG. 1 , which might occur if a water using appliance developed a leak or if condensate collected from an air conditioning system, for example. Control switch unit  34  may be of a type commercially available such as sold under the trademark Microswitch. Control switch unit  34  includes a switch actuator part  36  and an elongated actuator lever  38  hingedly connected to the switch unit at  40  and engageable with the actuator part  36 . Lever  38  may be spring biased to move about hinge or pivot point  40  in a clockwise direction, viewing  FIG. 1 , to a switch open position or a closed position, depending on the circuitry of the switch unit  34 . The switch actuating lever  38  includes a distal depending part  42  which is engageable with a water soluble tablet element  44  comprising, preferably, a biocide composition which is readily water soluble and is of a type which is normally placed in air conditioning system condensate pans to minimize the accumulation of aquatic growths or the like. Slot  32  is dimensioned to receive tablet  44  and is angled in a direction wherein the base of the slot  32   a  is engageable with the tablet, see  FIG. 1 . The tablet  44  is thus angled downwardly toward surface or base  32   a  and is unlikely to leave the slot  32  due to vibration or inadvertent movement of the pan  10 . Continuous spring pressure of the actuator arm  38  exerted on tablet  44  also aids in maintaining the tablet  44  in its working position shown in  FIGS. 1 through 3 . Switch unit  34  is adapted to be connected via suitable conductors  50  and  52 ,  FIG. 2 , to a suitable control unit  54 . Control unit  54  may be associated with an air conditioning system, for example, an alarm circuit or other apparatus in which excessive of amounts of condensate or leaking water may accumulate within pan  10  and, upon actuation of switch  14 , will result in the shutdown of such apparatus as well as possibly sounding an alarm. 
         [0018]    As shown in  FIGS. 1 and 2 , the configuration of the control switch  14  is advantageous in that the parts of the switch which are likely to be in contact with condensate or other sources of water do not include electrical circuitry associated with the switch unit  34 . However, the configuration of housing  16  also assures that tablet  44  will be thoroughly wetted and immersed in liquid as it rises to level  35  shown in  FIG. 1 . 
         [0019]    In operation, the control switch  14  is adapted to be placed in condensate or liquid leakage containment pan  10 , as illustrated in the drawings, suitably connected to control unit  54  or an alarm circuit and then armed by placing a tablet in the slot  32  and in engagement with the spring biased switch actuator arm  38 ,  42 . As condensate or leaking water collects in pan  10  it rises to a level wherein it contacts the tablet  44 . Tablet  44  will dissolve rather rapidly allowing the actuator arm  42  to move in a clockwise direction, for example, viewing  FIG. 1 , and causing the switch unit  34  to open or close to thereby send a signal to control unit  54  which could result in shutdown of an air conditioning system or generation of an alarm signal to bring to the attention of the user of a system associated with pan  10  that an abnormal level of water is collecting in the pan. Once the cause of the leakage or condensate accumulation has been corrected a new tablet  44  may be placed in slot  32  with switch actuator lever  38  depressed and in engagement with the tablet in preparation for further operation of the switch. 
         [0020]    Referring briefly to  FIG. 4 , there is illustrated a self-contained alarm system, generally designated by the numeral  60 , which may include a sealed enclosure  62  within which a circuit is provided including a source of power comprising a battery  64 , an on-off control switch  66 , a momentary pushbutton type test switch  68  and suitable alarm generating means, such as a buzzer or similar audio type alarm generator device  70 . Additionally, a visual indicator  72  comprising a light emitting diode, for example, may be placed in parallel with the audio alarm generator  70 . As shown in  FIG. 4 , control switch  14  is placed in circuit with the alarm generator so that when switch unit  34  closes audio and visual alarms are generated. Accordingly, the device or apparatus  60  may be installed with a control switch  14  in a location where at least one of an audio and visual signal may be detected if a malfunction occurs which results in liquid accumulation in a condensate collection or leakage containment pan, such as the pan  10  shown in  FIGS. 1 and 2  and described previously. 
         [0021]    Referring now to  FIG. 5 , there is illustrated an alternate embodiment of a control switch in accordance with the invention associated with a unit of heating, ventilating and air conditioning (HVAC) equipment, generally designated by the numeral  80 . The unit of HVAC equipment  80  is characterized by a thermostat  82  having at least terminals identified by the letters L/F, R, G, W and Y in accordance with conventional thermostat terminal markings. Thermostat  82  includes a visual temperature display  83  and a visual indicator  84  for indicating a system fault condition. System also includes a so-called indoor unit  86  including a circulating fan or blower  88  and a heater unit  90 . An outdoor unit, such as a vapor compression condenser unit  92  is illustrated as being associated with the system  80 . The indoor unit  86  would also include a cooling coil, not shown, operably connected to the outdoor unit for circulating a refrigerant fluid therebetween in a conventional manner. 
         [0022]    An alternate embodiment of a control switch in accordance with the invention is associated with the system  80  and is generally designated by the numeral  14   a . Switch  14   a  includes a switch unit  34   a  of the three way type supported in the housing  16  in place of the switch unit  34  and responsive to dissolving of the tablet  44  to move from the position shown in  FIG. 5  to an alternate position. For example, low voltage control power is supplied for the system  80  from a transformer  91  connected to terminal R of thermostat  82  and providing electrical power to terminal Y when the air conditioning system  80  is operating in a cooling mode and there is a call for cooling effect. In this mode, electrical power is supplied from terminal Y via a conductor  94  to switch unit  34   a  and, in the position shown, power is supplied to an indicator light  95  and to a relay  96  of the outdoor unit  92  causing a conventional vapor compression compressor and condenser to begin furnishing working fluid to the indoor unit to effect cooling operation. Moreover, if condensate collects in a condensate pan  10   a , similar to the condensate pan  10 , to a level which will dissolve the tablet  44  switch unit  34   a  will move to a position wherein power from thermostat terminal Y via conductor  94  will be conducted to a conductor  99  which is connected to the terminal L/F of thermostat  82  and will result in illumination of the indicator light  84 . Simultaneously, control power is shut off between conductor  94  and conductor  97  leading to the relay  96  so that the outdoor unit will cease operation resulting in loss of cooling effect delivered by system  80 , but also preventing additional collection of condensate in the condensate pan  10   a . In this way, a user of the system  80  will be alerted to a fault condition and may take corrective action to eliminate the adverse effects of unwanted accumulation of condensate in the pan  10   a.    
         [0023]    The construction and operation of the switches  14 ,  14   a , the alarm generator apparatus  60  and the system  80  are believed to be within the purview of one skilled in the art based on the foregoing description. Commercially available components may be utilized to construct the switches  14  and  14   a  except for the housing  16 , and commercially available components may be used to, essentially, construct the apparatus  60  and system  80 . The housing  16  is preferably formed of a suitable plastic having a density greater than water and may take other specific configurations while retaining the advantages described herein. 
         [0024]    Although preferred embodiments of the invention, including a switch and alarm apparatus have been described in detail herein, those skilled in the art will also recognize that various substitutions and modifications may be made to the invention without departing from the scope and spirit of the appended claims.