Abstract:
An alarm system for an AC assembly having an exterior located condenser supplied by a pressurized refrigerant system flowing between interior and exterior locations of a structure. A power source supplies an alarm panel at interior locations of the structure. A normally closed fluid pressure switch is electrically coupled between the power source and alarm panel and is maintained in an open and fluid communicating position upon detecting a continuous inlet fluid pressure. The pressure switch recloses upon sensing a decrease or loss of pressure, at which point a relay communicating closes to complete an electrical circuit between the power source and alarm panel. An alarm output in communication with the alarm panel responds to the closing of the relay to issue an alarm condition.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 11/845,196, filed Aug. 27, 2007, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/823,995, filed Aug. 30, 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention discloses a security alarm system such as in use with residential and commercial air conditioning (AC) assemblies, the alarm incorporating detection circuitry monitoring the internal fluid pressure of a cooling system and in order to detect damage indicative of sectioning and removal of copper lines and/or external located condenser components associated with the air conditioner assembly. 
       BACKGROUND OF THE RELEVANT ART 
       [0003]    Air conditioning units are being pillaged by thieves for intent on harvesting the copper and other recycle-able metals that the air conditioner might contain. Among other elements within the air conditioner, the coils, the condenser and the compressor may contain copper which hold street value to the criminals. For example, the copper may be sold to a reseller, a junkyard or the like. In response, a number of alarm systems have been developed to counteract such incidences of theft. A vulnerability of such alarm systems includes the exposure, such as at external locations of an associated structure which is accessible by the thieves, of critical circuitry and components the deactivation or removal of which can often short circuit whatever associated alarm protocol is provided for warning others of the theft in progress. 
       SUMMARY OF THE PRESENT INVENTION 
       [0004]    The present invention discloses a security or alarm system for use with such as the outdoor portions of an air quality conditioning (cooling) system including such as window or pad supported condenser units. As will be described in further detail throughout the following detailed description, the alarm system monitors a fluid pressure of the refrigerant incorporated into the cooling system at an internal (presumably inaccessible to the thieves) location and issues an alarm output upon sensing pressure loss, this occurring either through a leak or break in any associated conduit line which is typical upon a thief having cut into the pressurized system in the attempt to remove the copper piping or the like. 
         [0005]    It is an advantage of the present invention to provide such an alarm system with a first portion of the pressurized refrigerant system being located within a secure structure, such as the building being cooled by the air conditioning unit, as well as a second portion of the pressurized refrigerant system being located outside of the structure. The alarm system additionally provides for monitoring the pressure within the pressurized refrigerant system, such being fluidly coupled to the pressurized refrigerant system within the secure structure. A power source is communicated to the pressurized monitoring circuitry and operates to generate an alarm upon detecting a pressure drop across the pressurized refrigerant system. 
         [0006]    Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which: 
           [0008]      FIG. 1  is a schematic view of the alarm system according to an embodiment of the invention; 
           [0009]      FIG. 2  is a wiring diagram according to an embodiment of the invention; 
           [0010]      FIG. 3  is a wiring diagram according to another embodiment of the invention; 
           [0011]      FIG. 4  is a schematic view of the alarm system according to a further embodiment; and 
           [0012]      FIG. 5  is an associated wiring diagram corresponding to the embodiment of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Referring to  FIG. 1 , an air quality or conditioning system is generally illustrated at  10  according to one non-limiting variant of the present invention. The conditioning system  10  includes an external component  11  typically located outside of a structure  5  being cooled, as well as an internal component  12  located within the structure  5 . 
         [0014]    Individual pairs of refrigerant lines are represented at  13  and  13 ′ and extend between the external  11  and internal  12  components in communication with respective pluralities of heat transfer coils  14  (associated with the external component), as well as additional coils  14 ′ (associated with the internal component). The coils  14  and  14 ′ include any of evaporator coils, condensing coils and the like. 
         [0015]    A compressor  16  is incorporated into the external component  11  and in communication with selected refrigerant lines  13  and the coils  14 . A condenser  18  defines a major unit of the external component  11  and encloses the coils  14  and compressor  16 . Also, and while  FIG. 1  shows refrigerant lines  13  and  13 ′ extending outside compressor  16 , it is further contemplated that such refrigerant lines may be fully encapsulated within the compressor. 
         [0016]    Refrigerant is provided within one or more of the refrigerant lines  13  and  13 ′, communicating coils  14  and  14 ′, compressor  16  and condenser  18  such that the refrigerant moves through the system in a generally closed loop fashion. For brevity, such elements will be generically referred to as generic elements as such will be recognized by one of ordinary skill in the art. 
         [0017]    The refrigerant is provided within the refrigerant lines  13 , coils  14 , condenser  18 , and compressor  16  at a defined pressure in order to internally pressurize the fluid system, see further at  22  in  FIG. 1 . It is further understood that any application specific refrigerant exhibiting a defined internal pressure can be used and the invention can be instituted and practiced at any suitable pressure level. That is, one of ordinary skill in the art can implement the invention across a variety of pressure levels upon consideration of the present disclosure and the invention should not be limited to any specific pressure. 
         [0018]    Referring additionally to  FIG. 2  in cooperation with  FIG. 1 , an alarm is generally depicted at  20  and includes a pressure measurement device  24  connected to the internally pressurized system, schematically illustrated again at  22 . The pressure measurement device  24  is designed and calibrated to detect when a pressure drop occurs within the pressure system  22  and, as described below, to provide for an alarm notification output. For clarity, embodiments to accomplish the foregoing will now be described; however, it will be appreciated that a broad range of embodiments will be recognized due to the present disclosure and the invention should not be limited thereby. 
         [0019]    Referring again to  FIGS. 1 and 2  the alarm system  20  includes a power source  28  and an output  30  thereof (such as an audible siren, flashing light or other output including an alarm signal transmitted wirelessly or on-line to a remote location), the alarm output  30  also being in communication with the pressure measurement device  24 . In a preferred embodiment, the pressure measurement device  24  is a normally closed pressure switch which is defined as a switch which is normally open when pressure is detected at an inlet side, thus permitting pressurized fluid flow to nominally pass therethrough, the pressure switch subsequently reclosing upon sensing a loss in pressure, this further being indicative of cutting or other failure in the integrity of the associated fluid lines. Once the normally closed pressure switch  24  (re)closes, a circuit between the power source  28  and output  30  is completed (closed), this resulting in a voltage drop across an output  30 . 
         [0020]    In an alternative embodiment shown in  FIG. 3 , alarm  20 ′ includes pressure measurement device  24 , a relay  26 , power source  28  and output  30 . In this embodiment, pressure measurement device  24  is a normally open pressure switch that opens when a pressure drop is witnessed thereacross, and, for at least that reason, the disclosure hereof includes relay  26  for selectively coupling power source  28  to output  30 . In an embodiment, the relay  26  is arranged such that the voltage drop at output  30  is increased when a pressure drop is detected by pressure measurement device  24 , which therefore closes and completes the circuit. 
         [0021]    In either of the above embodiments, the output  30  is simply the voltage drop across a first wire  32  and a second wire  34  and such as will be greater when the pressure measurement device  24  detects a pressure drop thereacross. In a preferred embodiment, an output alarm device  36  is connected to the output  30  and may include such as a siren, a conventional alarm system, a telephone dialer, or the like. By additional example, this contemplates the output  30  being hardwired into a conventional home alarm system and work in conjunction therewith. 
         [0022]    As further shown in  FIG. 1 , the pressure measurement device  24  is mounted to the pressure system  22  at the internal component  12  of the cooling unit  10  and is contained within the secure structure  5  being cooled. As such, the portion of the alarm  20  that monitors the internal pressure and activates the alarm upon detecting a pressure drop is separated from the (typically exteriorly located) components it is protecting, again including refrigerant lines  13  and  13 ′, coils  14  and  14 ′, compressor  16 , and condenser  18 , which are ordinarily located within the external component  11  of the overall conditioning system  10 . Accordingly, and by mounting the alarm  20  and associated pressure measurement device  24  inside the structure  5 , the alarm may not be readily circumvented by potential thieves. 
         [0023]    It will be appreciated that the invention described herein will detect when the pressure system  22  is interrupted. Interruptions, for example, may occur due to theft of the unit or associated fluid lines and whereupon refrigerant is evacuated from the pressure system  22  as a result, as well as resulting from a non-theft incident and in which the volume and pressure of the internal refrigerant becomes low due to a leak in the system or the like. 
         [0024]    It will be appreciated that various type of refrigerant may be used and the invention should not be limited to any specific type of refrigerant. In an embodiment, the refrigerant may be Freon or a composite having FREON® therein. 
         [0025]    Referring now to  FIGS. 4 and 5 , an alarm system and associated wiring diagram are illustrated of an alarm system, generally at  38 , according to a further embodiment. A combined outside compressor and power monitoring relay is collectively represented by exterior subassembly  40  at a generally outside location relative to a proximately located structure (see wall  42  separating exterior and interior locations similar to that previously depicted in  FIG. 1 ). A weatherproof indoor/outdoor siren is further represented at  44  mounted to an exterior location of the wall  42 . 
         [0026]    A pair of pressurized conduit lines are commonly illustrated at  46  and extend from the outside subassembly  40 , through the wall  42  and to an interiorly located alarm panel  48 . A power supply  50  (also interiorly located) supplies power to the alarm panel  48 , such as via positive and negative wires  52  and  54 . The alarm panel  48  is typically mounted in series with an existing security alarm panel  56 , it being further understood that both panels  48  and  56  are, in certain original installations, capable of being integrated together. 
         [0027]    An interior air handling unit  58  is illustrated, such as including a conventional interior located furnace exhibiting a typical blower subassembly which is capable of working in cooperation with the exteriorly positioned condenser for providing interior air conditioning. Mounted atop the air handling unit  58  is a further collective subassembly depicted at  60  and which includes the arrangement of inner fluid coils and normally closed pressure switch (reference again being made to corresponding coils  14  and normally closed pressure switch  24  in the alternate variant of  FIG. 1 ). 
         [0028]    Additional features include the provision of a tilt/tamper switch  62 , such as mounted without limitation to the top inside of the condenser housing, and which triggers the alarm (panel  48  and connected siren  44  via output line  64 ), in the instance of any attempt to disassemble or remove the condenser unit cover. Also provided is a 480 Volt monitoring relay attaching to a contactor (see at  66  in  FIG. 5 ) within the condenser  40  (this defining part of the overall subassembly including the relay as further described in  FIG. 5 ) in order to monitor the electricity to the unit and to further signal the internally located alarm panel  48 , such as via further communicating line  68 , in the event of an attempt to shut off power to the unit. 
         [0029]    With reference finally to  FIG. 5 , a wiring diagram corresponding to the variant of  FIG. 4  is generally depicted at  70  and again references at  48  the alarm panel which is typically installed as part of the present invention in combination with existing security alarm panel further depicted at  56 . Power source (such as 220V) is again shown at  50  and extends, via wires  72  and  74  (corresponding to lines  52  and  54  in  FIG. 4 ) to a further subassembly  76  incorporating a contactor  78  (such that the wires  72  and  74  extend to input locations of the contactor  78 ) and which, as previously described, can be located within the interior of the condenser for monitoring the power supply delivered to the unit. 
         [0030]    A power monitor relay is further depicted at  80  and is communicated by output lines  82  and  84  extending from the contactor  78 . The relay  80  in turn outputting, via lines  86  and  88 , to selected locations of a first terminal strip  90  contained within the panel  48 . 
         [0031]    A normally closed pressure switch is further depicted at  92  and which is communicated, via wires  94  and  96 , to further input locations of a second terminal strip  98 , the same including further output wires  100  and  102  associated with output siren (see as also previously depicted at  44  in  FIG. 4 ). A third (smaller) terminal strip  104  provides output, via wires  106  and  108  to separately connected existing alarm panel  56 . 
         [0032]    Additional features associated with the alarm panel include on/off switch  110  and test button  112 . A 12 V transformer is further represented at  114  in communication with the panel  48 . 
         [0033]    The normally closed pressure switch and alarm protocol operates in the variant of  FIG. 4  in substantially the same manner as previously described in the variant of  FIG. 1  and by which a sensed loss of pressure along the fluid conduit lines  46  (such as indicated of an attempt to section the lines from an exterior location) causes the relay  80  to close a circuit with the alarm panel  48  (via output lines  86  and  88  to terminal strip  90 ) and the panel  48  in turn to activate siren  44  via further output lines  100  and  102  extending from terminal strip  98 . 
         [0034]    The configuration of the normally closed pressure switch  92  is further such that the alarm only triggers in the event that the refrigerant (conduit) lines are cut and does not provide a false signal in the instance of a pressure variation resulting only from uneven fluid pressure or flow within the conduit lines which may not be representative of an attempt to cut the lines. Also, the present design is constructed so that the alarm will trigger in the instance of any interruption of power to the AC unit (e.g. including outside condenser). 
         [0035]    It is also envisioned that multiple exterior located condenser units (i.e. up to four) can be connected to a single alarm panel  48 . The alarm panel  48  can be further configured such that it communicates directly with the existing alarm panel  56  (such as additional to the siren output described above) and further in order to notify the existing alarm company (via the communication link established between the existing panel) in the event of an alarm condition. 
         [0036]    Additional features include the incorporation of a phone dialer in the alarm panel  48  (see as depicted at  116 ) which can dial a given number of reaching a designated phone  118  if the alarm system is triggered. A separate portable battery source (see at  120  in  FIG. 5 ) can also be provided via wires  122  and  124  tapping into contactor wires  72  and  74 , respectively, and in order to operate the alarm system in the instance of loss of utility power to the facility. 
         [0037]    Having described my invention, other and additional preferred embodiments will become apparent to those of ordinary skill in the art to which it pertains, and without departing from the scope of the appended claims.