Abstract:
The disclosure includes improvements in the field of retrofit-detector installation such as adapters that simplify retrofit of addressable detectors onto previously installed zone-type system hardware. Each adapter includes electrical circuitry for electrically connecting new addressable detectors with legacy system once installation is complete. The disclosure includes structures that permit users to efficiently solve a number of problems that may arise during installation of retrofit-detectors into legacy systems. For example, one or more switches may be used to reverse electrical polarity to thereby correct polarity and/or mapping faults. One or more switches may also be provided to disconnect at least one electrical terminal to assist in locating ground faults and/or other wiring problems. One or more test points may also be provided to test one or more electrical characteristics relevant to retrofit installations.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is directed to systems, methods, apparatus and related components that facilitate the installation of new detectors into legacy detector systems. More particularly, the invention relates to facilitating the conversion of zone-type heat, fire and/or smoke detector systems to addressable heat, fire and/or smoke detector systems. Accordingly, the general objects of the invention are to provide novel systems, methods and apparatus of such character. 
   2. Description of the Related Art 
   Heat, fire and smoke detectors/alarms have been widely installed in both commercial and residential structures to protect their inhabitants and other contents for many years. Since these building often last much longer than detector and alarm technologies, there are currently many older buildings that are equipped with technologically outdated protection systems. One particularly common protection system technology that has become outdated is that of the zone-type system. Since an understanding of zone-type systems is helpful in appreciating certain aspects of the present invention, however, a discussion of zone-type systems follows. 
   A representative zone-type protection system  10  is illustrated in  FIG. 1 . As shown therein, a conventional zone-type system uses plural heat, fire or smoke detectors  9 ,  9 ′ configured in a so-called detector loop  13  that terminates at and is electrically coupled to a control panel  11 . In such a system, each detector loop  13  typically comprises plural wires (most often a pair of wires) that have been strung through various locations during the construction of a structure. Each detector loop is electrically coupled to a number of detectors  9 ,  9 ′ with an end-of-line resistor at one end and a control panel  11  to the other. A typical industrial zone-type system may include hundreds of detectors arranged in several zones (each of which may have one or more loops). Subsequent completion of the structure hides these loops from access except where the wiring is connected to a detector or control panel. 
   The detectors used in the above-noted systems are generally of the following three types: flame detector, thermal detector, or smoke detector. These three classes of detectors correspond to the three primary properties of a fire: flame, heat, and smoke and may be designed to sense smoke obscuration, ionization, temperature, or the like, all of which may be indicative of a fire. Conventional zone-type detector assemblies of the type used in the system  10  of  FIG. 1 , typically include a base  20  (as shown in  FIG. 2 ) and a complementary detector (not shown). Conventional zone-type detector base  20  generally includes a body  21  with a detector-mating rim  25 , at least two mounting apertures and a plurality of electrical terminals  22   a  through  22   d.  During installation of base  20 , body  21  is affixed to the surface of a wired building via the mounting apertures and the detector loop wiring is hardwired to terminals  22   a  through  22   d.  For example, a pair wires from an incoming leg of a detector loop may be connected to terminals  22   a  and  22   b  as shown in  FIG. 1  and as known in the art. Similarly a pair of wires for a downstream leg of the detector loop may be connected to terminals  22   c  and  22   d  as shown in  FIG. 1  and as known in the art. It will be appreciated that the desired electrical circuitry will be completed by mating a conventional zone-type detector onto, now mounted, base  20  as is known in the art. In this way, each zone-type detector is electrically connected to the detector loop via the electrical connections within base  20 . 
   A typical zone-type detector is designed to operate in an on/off mode by changing from an inactive state to an active state whenever the environmental condition that the detector is designed to monitor exceeds a predetermined threshold. In the active state, the internal resistance of the detector is lowered, thereby increasing the current flow through the detector loop. Control panel  11  provides the operating current for the detector loop and includes a current sensing mechanism communicatively linked to the detector loop. When the current flow level in the detector loop exceeds a predetermined threshold, control panel  11  activates an alarm and/or discharges a fire suppressant such as water, halon, etc. as is known in the art. 
   While such zone-type systems offer some advantages over older systems, one of their deficiencies was that they could only direct users&#39; attention to the zone in which an emergency condition was detected (as opposed to the precise location of the detected emergency condition). This deficiency was solved with the introduction of more sophisticated detector systems with a control panel that is communicatively linked to microprocessor-based “addressable” detector assemblies of the type shown in exploded view in  FIGS. 3   a  and  3   b.  As known, detector  12  preferably reports alarm conditions via radio transmission to a control panel. 
   Like zone-type detector assemblies  9 , addressable detector assemblies  12  typically include a base  20 ′ and a complementary detector  30 . Detector  30  includes electrical terminals  32   a,    32   b,    32   c  and  32   d  and a body with a rim  35 . Base  20 ′ includes a body  21 ′ with a pair of surface mounting apertures and a rim  25 ′ designed to mate with rim  35  of detector  30 . Base  20 ′ further includes electrical terminals  22   a ′,  22   b ′,  22   c ′ and  22   d ′. In use, terminals  22   a ′ through  22   d ′ are hardwired directly to detector loop wiring  13  and are also electrically coupled to respective terminals  32   a  through  32   d  of detector  30  as is known in the art. 
   Several examples of the above-discussed addressable detector assemblies include those in the “Signature Series” produced and sold by Edwards Systems Technology of Cheshire, Conn. under the designations “SIGA-PS,” “SIGA-AB4,” “SIGA-IB,” and “SIGA-RB.” Other examples of addressable detectors are well known in the art. 
   Addressable detectors of the type discussed above represent an advance in that each detector  12  has the ability to report its location when communicating the presence of an emergency condition. Further, they may produce signals that they are capable of indicating the magnitude of the parameters being sensed, rather than just active-inactive signals. The addressable system control panel, which is typically microprocessor-based and under software control, analyzes the information transmitted from detector assembly  12  to determine whether an alarm condition exists and, if so, where the reporting detector is located. 
   For these and other reasons, addressable systems have, essentially replaced zone-type systems in new installation applications. Additionally, many previously installed zone-type systems are being upgraded with addressable detectors and control panels specifically designed to retrofit zone-type systems. Since such retrofit systems utilize the legacy detector loop wiring  13  from the zone-type system  10 , they are substantially less expensive than installation of a completely new addressable system. 
   In a typical retrofit application, addressable detector assembly  12  would be retrofit into a zone-type system by removing zone-type detector assembly  9 ′ and connecting base  20 ′ to the existing detector loop wiring  13 . In particular, legacy detector assembly  9  would be disconnected from its associated legacy wiring  13  and removed from the building to which it was affixed. Addressable base  20 ′ is then affixed to a desired location (typically the same location as the newly removed zone-type base) and electrically connected to the, newly disconnected, legacy wiring  13 . Further, addressable detector  30  is mated with addressable base  20 ′ such that detector  30  is electrically connected to the legacy detector loop wiring  13  via base  20 ′. 
   If necessary, one may manually disconnect an end of line device from the initiating circuit, to permit the existing circuit to accept new addressable devices. Often the location of this device is unknown, as it is traditionally mounted behind an existing device in the electrical junction box. Nonetheless, conventional retrofit applications sometimes require identification and removal of such end of line devices. This is normally a difficult and labor-intensive step. 
   Although retrofit applications of the nature described above are less expensive than new installations, they are still labor-intensive, complicated and expensive endeavors that rely heavily on skilled technicians. For example, most retrofit projects involve manual removal of every zone-type detector from its location and from its associated wiring, testing of the wiring leading throughout each zone and to each detector, diagnosis of certain wiring problems and/or conditions, and manual connection and affixation of the new addressable detectors. Among the most common of such problems are (1) reverse polarity wiring; (2) ground faults; and (3) a need to disconnect an end-of-line device. Furthermore, the facts that (1) every building is different; (2) a wide range of detector systems have been used throughout the years; and (3) customer preferences vary from project to project, make each retrofit project unique. Thus, installation decisions must be made on the fly and unanticipated problems solved during installation. It will be readily appreciated that highly skilled technicians are required to perform this complex set of tasks. Such technicians are costly, in short supply and difficult to train. It will also be appreciated that retrofit projects of the type discussed above necessarily interfere with normal operations of the buildings (typically housing businesses) in which they occur. It is, therefore, highly desirable to minimize the time for implementing retrofit upgrades. 
   There is, accordingly, a need in the art for improved methods, systems and apparatus to facilitate conversion of zone-type systems into addressable systems. In particular, such methods and apparatus should envision simplified apparatus and techniques for integrating addressable detectors into legacy zone-type system hardware. Such methods, systems and apparatus will ideally offer users/purchasers an optimal combination of (1) simplicity; (2) reliability; (3) economy; and (4) versatility. 
   There is a further need in that art for improved methods and apparatus for converting zone-type systems into addressable systems that are capable of solving a variety of common problems associated with retrofit installations such as (1) reverse polarity wiring; (2) ground faults; and (3) a need to disconnect an end-of-line device. 
   SUMMARY OF THE INVENTION 
   The present invention satisfies the above-stated needs and overcomes the above-stated and other deficiencies of the related art by providing improved methods, systems and apparatus for enabling addressable detector assemblies to be installed directly onto previously wired zone-type detector bases. Thus, the invention obviates the need for and use of conventional addressable detector bases during conversion of zone-type systems into addressable systems. Further, the invention also obviates the need to remove zone-type detector bases during conversion of zone-type systems into addressable systems. The invention also eliminates the need to manually hardwire addressable detector assemblies and/or bases into the legacy detector loop wiring during conversion of zone-type systems into addressable systems. Moreover, preferred aspects of the invention permit certain troubleshooting tasks to be readily and conveniently performed. Additionally, such methods and apparatus offer an optimal combination of (1) simplicity; (2) reliability; (3) economy; and (4) versatility. 
   One form of the invention relates to improvements in retrofit-detector installation and, in particular, adapters that permit addressable detectors to be mounted onto previously installed zone-type detector bases. The inventive adapters simplify addressable detector installation and include a set of electrical contacts electrically linking newly installed detectors to legacy bases and detector loop wiring once installation is complete. 
   One optional feature of the preferred embodiment of the invention envisions the use one or more switches that solve a number of common installation problems. These may include (1) reverse polarity wiring; (2) ground faults; and (3) a need to disconnect an end-of-line device. For example, the inventive adapters may include one or more manual switches to reverse input and/or output wiring (e.g., reverse the polarity of either an individual detector or a branch of a given circuit), to thereby correct polarity and/or mapping faults. Another optional feature of a preferred embodiment envisions the use of one or more switches that may be used to disconnect one or more of the electrical paths through an adapter to thereby assist in locating ground faults and/or other wiring problems. 
   In a related form, the present invention is directed to improved methods to facilitate installation of addressable detectors into legacy zone-type system hardware to thereby facilitate conversion of zone-type systems into addressable systems. 
   Numerous other advantages and features of the present invention will become apparent to those of ordinary skill in the art from the following detailed description of the preferred embodiments, from the claims and from the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiments of the present invention will be described below with reference to the accompanying drawings where like numerals represent like steps and/or structures and wherein: 
       FIG. 1  illustrates a representative zone-type detector system in accordance with the prior art; 
       FIG. 2  illustrates a representative zone-type detector base in accordance with the prior art, the base of  FIG. 2  being used in the system of  FIG. 1 ; 
       FIG. 3   a  is a first exploded view of an addressable detector assembly in accordance with the prior art; 
       FIG. 3   b  is a second exploded view an addressable detector assembly in accordance with the prior art; 
       FIG. 4   a  depicts an inventive adapter in accordance with one preferred embodiment of the present invention, the adapter being shown in conjunction with a zone-type base and an addressable detector; 
       FIG. 4   b  is another view of the inventive adapter, zone-type base and addressable detector depicted in  FIG. 4   a;    
       FIG. 5   a  is a detailed front view of the inventive adapter of  FIGS. 4   a  and  4   b;    
       FIG. 5   b  is a detailed rear view of the inventive adapter of  FIGS. 4   a  through  5   a;    
       FIG. 6   a  is a schematic representation of the inventive adapter of  FIGS. 4   a  through  5   b:    
       FIG. 6   b  is a schematic representation of an inventive adapter in accordance with an alternative embodiment of the present invention; and 
       FIG. 6   c  is a schematic representation of another inventive adapter in accordance with a different alternative embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An inventive adapter in accordance with one preferred embodiment of the present invention is shown in  FIGS. 4   a  and  4   b.  As shown therein, an inventive adapter  40  is designed for use with a conventional zone-type base  20  and a conventional addressable detector  30 . Adapter  40  preferably includes a body  41  with opposing rims  45  and  45 ′ that are designed to mate with base  20  and detector  30  respectively. Adapter  40  further includes electrical terminals  42   a,    42   b,    42   c  and  42   d,  which are designed to electrically engage terminals  22   a,    22   b,    22   c  and  22   d  of base  20  respectively. Adapter  40  further includes electrical terminals  42   a ′,  42   b ′,  42   c ′ and  42   d ′, which are designed to electrically engage electrical terminals  32   a,    32   b,    32   c,  and  32   d  of detector  30  respectively. However, it will be understood that terminals  42   c ′,  42   d ′,  32   c  and  32   d  are not necessary for functionality and, hence, may be disconnected or otherwise rendered non-functional. 
   In use, rim  45  of adapter  40  is mated with rim  25  of base  20  to thereby establish the aforementioned electrical connections between adapter  40  and base  20 . Because base  20  has remained hardwired into detector loop wiring  13  since its original installation, terminals  42   a  through  42   d  are also electrically coupled to the detector loop wiring  13  via base terminals  22   a  through  2   d.  Similarly, in use, rim  35  of detector  30  is mated with rim  45 ′ of adapter  40  to thereby establish the aforementioned electrical connections between adapter  40  and detector  40 . In addition to the aforementioned structures, a tamper resistant structure may also be formed from the engagement of tab  47  of adapter  40  (see  FIG. 5   b ) and tab  37  of base  30  (see  FIG. 4   b ). 
   With additional reference now to the detailed front and rear views of  FIGS. 5   a  and  5   b,  it will be better appreciated that terminals  42   a  through  42   d  and  42   a ′ through  42   d ′ are preferably electrically coupled via circuitry concealed within body  41 . In particular, body  41  preferably includes a cover  46  mounted via screws  43   a  through  43   c  to thereby enclose circuitry that is schematically depicted in  FIG. 6   a  and discussed in greater detail below. This circuitry preferably includes a first switch  44   a  for selectively reversing the polarity of electricity presented to the terminals of base  20 . This may be useful, for example, where the detector loop wiring was originally incorrectly hardwired onto base  20 . As shown, first switch  44   a  is preferably accessible to a user after adapter  40  has been mated with base  20 . This permits a user to conveniently diagnose and correct polarity problems encountered after adapter  40  has been affixed to base  20 . Significantly, this can occur without disassembling any components and cannot be readily changed after a detector has been mated with an adapter. If there are no problems, or if they have been corrected, detector  30  can then be affixed to adapter  40  with confidence that proper operation will result without additional difficulty. 
   Similarly, a second switch  44   b  for selectively disconnecting the connection between at least one of terminals  42   a  and  42   b  from detector loop wiring  13  is preferably included in adapter  40  such that switch  44   b  is accessible after adapter  40  has been mated with base  20 . This also permits a user to conveniently diagnose and correct problems encountered after adapter  40  has been affixed to base  20 . For example, a user may use switch  44   b  to selectively prevent detector loop current from flowing to terminal  42   d  to thereby disconnect an end of line device if desired. Significantly, this can occur without disassembling any components and cannot be readily changed after a detector has been mated with an adapter. If there are no problems, or if they have been corrected, detector  30  can then be affixed to adapter  40  with confidence that proper operation will result without additional difficulty. 
   Turning primarily now to  FIG. 6   a,  there is shown therein a schematic representation of adapter  40  of  FIGS. 4   a  through  5   b  including the aforementioned terminals, switches and the, preferably enclosed, circuitry. As shown therein, adapter  40  includes circuitry electrically coupling terminals  42   a  and  42   b  with terminals  42   c,    42   d,  and  42   a ′ through  42   d ′. The circuitry preferably includes a single-pull double-throw switch that reverses the polarity of signals presented at terminals  42   c  and  42   d  if second switch  44   b  is closed. Further, the circuitry preferably includes a single-pull single-throw switch that disconnects terminal  42   b ′ from the remainder of the detector loop if desired. Effectively, this can be used to disconnect a legacy end of line resistor. An additional, preferable feature is the provision of testing points, or test terminals,  49   a  and  49   b  that are exposed for access after an adapter has been mated with a base. In an alternative embodiment, not shown, terminals  42   c ′ and  42   d ′ may be replaced with test points  49   a  and  49   b.    
   Turning now to the schematic representation of an alternative adapter  40 ′ shown in  FIG. 6   b,  one may see that alternative adapter  40 ′ preferably includes an isolator circuit  50  which is preferably in the form of a line fault isolator for use on class A circuits. Isolator circuit  50  may be desirable to prevent or eliminate ground loops issues that may exist in the detector loop. Further, test points  49   a ′ and  49   b ′ are provided at points in the circuit that are isolated via isolator  50 . 
   A schematic representation of another alternative adapter  40 ″ is shown in  FIG. 6   c.  As shown therein, alternative adapter  40 ″ includes a relay interface  52  and terminals  54   a,    54   b  and  54   c.  Preferably, relay operational mode can be selected as either “normally open” or “normally closed” during installation of inventive adapter  40 ″. Further, the position of relay interface  52  can preferably be remotely supervised to avoid accidentally jarring it out of position. Finally, if this variant of the invention is programmed to do so, it may be operated as a control relay. As shown, test points  49   a ″ and  49   b ″ are preferably located and operate in the same way as test points  49   a  and  49   b  of adapter  40  discussed above. 
   The substantial temporal and economic benefits of the present invention will now be illustrated via an economic analysis of a representative retrofit application. In a typical retrofit project performed in accordance with the prior art methods and apparatus, a building might have about 200 distributed zone-type detectors to be replaced and some additional control electronics to be upgraded at a central location. At an average of 15 minutes per detector and an average of $75.00 per hour for a technician, the zone-type detectors could be upgraded to addressable detectors in about 50 man-hours or $3750.00. Thus, a pair of technicians could complete this project in about three days. At an average cost of $15.00 per detector, the detectors would cost about $300.00 yielding a total cost for the detector portion of the project of $6750.00. 
   By contrast, the methods an apparatus of the present invention would cost far less, radically reduce the interference with use of the building and make technicians more available to complete other projects. Using the invention, the appropriate portions of each zone-type detector could be replaced with a corresponding addressable device in about 5 minutes and a project with 200 devices could be completed in about 16 man-hours. A pair of technicians could complete this task in a single day at a cost of about $1200.00, thereby saving about $2550.00. Further, since the present invention obviates the need to use a new addressable detector base, little no or additional cost for materials would be necessary. In addition to increasing availability of the technicians, the present invention radically reduces the time that operations at the subject building are interfered. 
   While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to encompass the various modifications and equivalent arrangements included within the spirit and scope of the appended claims. With respect to the above description, for example, it is to be realized that the optimum dimensional relationships for the parts of the invention, including variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the appended claims. Therefore, the foregoing is considered to be an illustrative, not exhaustive, description of the principles of the present invention.