Abstract:
Moisture-resistant electronic enclosures and methods of enclosing and isolating an electronic metering device are disclosed. The electronic enclosure can be adapted for metering devices, such as in automatic meter reading and other consumption measuring application, and includes a double-wall, isolated configuration. The apparatus and method of the invention thereby protect metering or other electronic components from moisture, dust, and other environmental debris.

Description:
RELATED APPLICATIONS AND CLAIM TO PRIORITY 
     This application claims priority to U.S. Provisional Patent Application No. 60/568,284, filed on May 5, 2004, and entitled “DOUBLE WALL ISOLATED REMOTE ELECTRONIC ENCLOSURE APPARATUS,” which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to meter enclosures, and more particularly to waterproof electronic meter enclosures. 
     BACKGROUND OF THE INVENTION 
     Automatic meter reading (AMR) systems are generally known in the art. Utility companies, for example, use AMR systems to read and monitor customer meters remotely, typically using radio frequency (RF) communication. AMR systems are favored by utility companies and others who use them because they increase the efficiency and accuracy of collecting readings and managing customer billing. For example, utilizing an AMR system for the monthly reading of residential gas, electric, or water meters eliminates the need for a utility employee to physically enter each residence or business where a meter is located to transcribe a meter reading by hand. 
     Remote meters operating as part of AMR systems are typically mounted externally on a building, pipe, pole, or other structure, or in a pit, exposing the meters to a variety of climate conditions. While meter electronics are capable of operating in a variety of environment temperatures, the function and performance of remote meters and their associated components are adversely affected by moisture. Further, although remote meters can be successfully shielded or protected from rain or snow, it is difficult to protect the remote meters from high humidity. 
     Previous solutions include fully encapsulating remote meters that are exposed to humid or wet environments. These meter housings are expensive with respect to both component materials and manufacturing costs. Completely encapsulating a remote meter also affects the engineering and design of the meter, adding to the overall cost of the remote meter and decreasing the cost-savings associated with implementing an AMR system. 
     There is, therefore, a need in the industry for a remote meter housing that addresses the cost and design shortcomings of current meter housings while providing effective protection of electronic components from moisture. 
     SUMMARY OF THE INVENTION 
     The present invention substantially meets the aforementioned needs of the industry, in particular by providing a double wall isolated remote meter enclosure apparatus. The enclosure apparatus provides effective protection of electronic meter components from moisture and is less expensive to manufacture and implement than current meter enclosures. 
     In one preferred embodiment, a moisture-resistant electronic enclosure adapted for use in metering applications comprises a main housing, a main housing cavity lid, a main housing cover, and a mounting plate. The main housing preferably comprises a back wall having an interior surface and an exterior surface, and a sidewall extending laterally from the interior surface, the sidewall having a distal end portion, longitudinal side portions, a top portion between the side portions and opposite the distal end portion, an interior sidewall surface, and an exterior sidewall surface, the interior sidewall surface and the interior surface of the back wall defining a main housing cavity. One embodiment of the main housing cavity lid is interengageable with the main housing and comprises an interior lid surface and an exterior lid surface. The main housing cavity is bounded by the interior lid surface. The main housing cover comprises first and second cover walls and a cover sidewall laterally joining the first and second cover walls on at least three sides. An interior surface of each the first and second cover walls and cover sidewall defines an air gap between the main housing cover and each the main housing and the main housing cavity lid, and a distal end portion of the cover sidewall comprises an aperture through which the main housing cover slidably interengages with the main housing. In one embodiment, the main housing cover further comprises a fastening assembly removably coupleable with the main housing. The mounting plate is coupled to the exterior surface of the main housing in one embodiment and can be integral with the main housing in another embodiment. 
     According to another preferred embodiment, a moisture-resistant electronic enclosure adapted for use in metering applications comprises a main housing, a bottom lid and top lid each interengageable with the main housing, and a main housing back plate. The main housing comprises a back wall having an interior surface and an exterior surface, and a sidewall extending laterally from the interior surface, the sidewall having first and second end portions each disposed between first and second side portions, an interior sidewall surface, and an exterior sidewall surface in one embodiment. The interior sidewall surface and the interior surface of the back wall define a main housing cavity having at least one main housing subcavity. The bottom lid preferably is interengageable with the main housing within a main housing subcavity and comprises an interior lid surface bounding the main housing subcavity on one side and an exterior lid surface defining an air gap between the bottom lid and the interior surface of the back wall. The top lid has an interior lid surface and an exterior lid surface, the interior surface bounding the main housing subcavity on another side to form a potting cavity. The main housing back plate is preferably interengageable with the main housing and has an interior plate surface and an exterior plate surface in one embodiment. The main housing cavity is bounded on at least one side by the interior plate surface, the interior plate surface further defining an air gap between the main housing back plate and the exterior lid surface of the top lid. 
     Methods for enclosing and isolating an electronic metering device are also disclosed. In one embodiment, a a moisture resistant enclosure comprising a main housing, a main housing cavity lid coupleable to the main housing and defining a main housing cavity, and a main housing cover slidably interengageable with the main housing, an interior surface of the main housing cover defining an air gap between the main housing cover and each the main housing and the main housing cavity lid, is supplied. An electronic metering device is arranged within the main housing cavity and the main housing cavity lid is secured to the main housing to enclose the main housing cavity, forming a double-wall isolated enclosure by placing the main housing cover over the main housing. The double-wall isolated enclosure can then be mounted for interconnection with other metering components. The method can also comprise the step of potting the main housing cavity. 
     In another embodiment, a moisture resistant enclosure comprising a main housing, a top lid and a bottom lid disposed within the main housing and bounding at least a portion of a main housing subcavity, and a main housing back plate interengageable with the main housing, an interior surface of the main housing defining an air gap between the main housing and an exterior surface of the bottom lid, and an interior surface of the main housing back plate defining an air gap between the main housing back plate and an exterior surface of the top lid, are supplied. An electronic metering device is arranged within the main housing subcavity between the top lid and the bottom lid, and the main housing back plate is secured to the main housing to form a double-wall isolated enclosure. The double-wall isolated enclosure can then be mounted for interconnection with other metering components. 
     The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description that follow more particularly exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an enclosure according to one embodiment of the invention. 
         FIG. 2  is a front view of the enclosure of  FIG. 1 . 
         FIG. 3  is a side sectional view of the enclosure taken along line A—A of  FIG. 2 . 
         FIG. 4  is an exploded view of the enclosure of  FIG. 1 . 
         FIG. 5  is an exploded view of an enclosure according to one embodiment of the invention. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The double wall isolated remote electronic enclosure apparatus disclosed herein minimizes the affect of moisture and liquid water on meter electronics while reducing the associated part and manufacturing costs. The invention can be more readily understood by reference to  FIGS. 1–5  and the following description. While the invention is not necessarily limited to such an application, the invention will be better appreciated using a discussion of example embodiments in such a specific context. 
     Referring to  FIGS. 1–4 , an enclosure  10  comprises a main housing  12 , a mounting plate  14 , and a main housing cover  16  in one preferred embodiment. Main housing  12  comprises a back wall  18  and a sidewall  20  that define an internal main housing cavity  22  to house a power source  24 , such as a battery or other cell, a printed circuit assembly  26 , and/or other electronic components, and to isolate components  24  and  26  from housing cover  16  and other external walls. Back wall  18  and sidewall  20  can be sized or arranged to mount or isolate printed circuit boards and electrical components of varying sizes and configurations in other embodiments of the invention. 
     In one embodiment, main housing  12  comprises one or more interior walls  27  to define at least one subcavity  28  of cavity  22 . Subcavity  28  can house other specialized electronic components necessary or desired for particular applications and uses of enclosure  10 . 
     Enclosure  10  further comprises a main housing cavity lid  30 . Lid  30  preferably is secured in place, for example by snapping, ultrasonic welding, or otherwise fastening, to enclose cavity  22 , and/or subcavity  28 , and cover electronic components  24  and  26 . 
     Mounting plate  14  preferably comprises mounting means  32  for directly mounting enclosure  10  to a pipe, wall, or other structure in one embodiment. For example, mounting means  32  as depicted in the embodiment of  FIGS. 1–4  comprise an interface for a pipe bracket to secure enclosure  10  to a pipe. Mounting means  28  can also comprise a built-in bracket, clamp, fastener, fastener or hardware aperture, interface, and the like for mounting or otherwise securing enclosure  10  to a structure. In one preferred embodiment, mounting plate  14  is integral to main housing  12 . 
     Housing cover  16  completes the double-wall isolation of the internal electronic components and preferably slides over and interengages main housing  12 . Housing cover  16  comprises first and second substantially parallel cover walls  34  and  36  joined by a lateral sidewall  38 , a distal end portion of sidewall  38  comprising an aperture  40  through which housing cover  16  slidably engages main housing  12 . A fastening assembly  42  removably couples cover  16  with housing  12 . Fastening assembly  42  can comprise, for example, snap fasteners or other interlocking means, such as fasteners with corresponding apertures and the like. 
     The double-wall isolated design of enclosure  10  protects electronic components  24  and  26  from moisture, dust, insects, and other environmental debris in part by increasing the amount of time required for moisture to breach enclosure  10 . Housing cover  16  and housing  12 , including lid  30 , form a three-layer barrier in conjunction with an air gap defined between an interior surface of cover  16  and housing  12  and lid  30 . Thus, moisture must penetrate outer cover  16 , saturate the air gap, and subsequently penetrate housing  12  and lid  30  prior to reaching and affecting internal electronic components  24  and  26 . The double-wall isolated design of enclosure  10  therefore reduces the amount of moisture or other matter to which electronic components  24  and  26  are exposed. When used in remote meter applications, for example gas, water, or other utility meters, enclosure  10  improves reliability and functionality of electronic components housed therein and reduces field maintenance requirements. These benefits improve the overall efficiency and cost-effectiveness of AMR and other metering systems. 
       FIG. 5  is an exploded view of another preferred embodiment of enclosure  10 . Enclosure  10  according to one preferred embodiment of the invention includes main housing  12 , which can house a power source, a printed circuit board, and other electronics, and which forms a first line of protection from the ambient environment; a bottom lid  44 , which creates a bottom double wall when interengaged with housing  12  and can be adapted to mount, secure, or otherwise hold a printed circuit board and other components; a top lid  46 , which is adapted to enclose the electronics, forms one of the double walls with housing  12 , and also creates a potting cavity for pit applications; and a housing back plate  48 , which forms an exterior wall and can be adapted to mount or otherwise affix enclosure  10  to a pipe, wall, or other structure by a pipe bracket interface, a fastener, a fastening aperture, a mounting bracket, a clamp, and the like. A subcavity  52  of main cavity  50  is thereby formed between bottom plate  44  and top plate  46  when plates  44  and  46  are in place within housing  12 . Enclosure  10  therefore further comprises an isolated circuit subcavity  52  within housing  12  and cavity  50 , the cavity having an air gap separating the outer walls of housing  12  and back cover  48  from plates  44  and  46 , respectively. 
     Enclosure  10  preferably comprises a molded plastic but can also comprise other durable and moisture-impermeable materials suitable for indoor or outdoor mounting known to those skilled in the art. The particular design, size, arrangement, and configuration of main housing  12 , cavities  22  and  24  or  50  and  52 , and other components of enclosure  10  can vary or be customized according to the specific application or use of enclosure  10  while maintaining the double-wall isolated design described above with reference to the preferred embodiments of  FIGS. 1–5 . 
     For example, enclosure  10  is preferably designed for compatibility with a wide range of meter products manufactured by different companies, including those used in various global regions and countries. Accordingly, preferred embodiments of enclosure  10  can be customized for AMR and general electrical distribution systems used in these varied areas. Enclosure  10  can be further adapted in other embodiments for pit environments, in which enclosure  10  is submersed. For example, main housing  12  or enclosure subsurfaces can be potted to create a seal around any leads, wires, or other interconnects extending from the interior of enclosure  10  to the exterior, preventing water intrusion in the case of submersion of enclosure  10 . In another embodiment, the enclosure  10  is submersed in a pit without any potting of leads, wires, and other interconnects within the enclosure subsurfaces of the double wall enclosure. 
     A preferred embodiment of the invention therefore also comprises a method of enclosing and isolating electronic components located in a humid or wet area. Referring by way of example to the embodiment of  FIGS. 1–4 , but not excluding the embodiment of  FIG. 5  and other preferred embodiments, electronic components  24  and  26 , for example electronic utility meter components, are mounted in main housing  12  of enclosure  10 . Lid  30  is secured, forming a first main wall of protection from moisture, water, dust, and other debris. Housing cover  16  is placed over main housing  12 , defining an air gap between housing cover  16  and main housing  12 . Cover  16  in communication with main housing  12  forms double-wall isolated electronics enclosure  10 . Enclosure  10  is then mounted via mounting means  32  to a wall, pipe, or other structure for interconnection with other meter or electronic components and integration into an AMR system, for example. 
     The apparatus and method of the invention therefore protect meter or other electronic components from moisture, dust, and other environmental debris. The invention also reduces the costs associated with manufacturing electronics enclosures and eases integration of meters or other electronic components into new or existing AMR systems. 
     The invention may be embodied in other specific forms without departing from the spirit of the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.