Abstract:
A method and apparatus for upgrading in-service or legacy telecommunications cabinets that improves power, cooling, space and EMI capabilities, allowing the cabinet to house updated, telecommunications equipment. The upgrade modules include an extension collar that replaces legacy doors, allowing the attachment of replacement doors having integral heat exchanger units. The extension collar also has support for Electro-magnetic Interference (EMI) shielding gaskets so provide EMI shielding capable of meeting FCC mandated levels. Additional upgrade modules include a battery chamber attached beneath the base of legacy cabinet, cooled and vented by one or more of the heat exchanger doors, thereby providing longer battery life.

Description:
FIELD OF THE INVENTION 
     The present invention relates to systems and apparatus for telecommunications cabinets and particularly to systems and apparatus for upgrading inservice telecommunications cabinets. 
     BACKGROUND OF THE INVENTION 
     During deregulation of the telecommunications industry in the early 1980&#39;s many thousands of telecommunications cabinets were installed to support the expansion of the phone network. These cabinets were typically placed near urban developments by the telephone companies to provide local access and contained telecommunications equipment. 
     Since the initial installation and population of these cabinets, telecommunications equipment has advanced. In particular, phone systems have evolved to provide significantly higher line density. In order to provide adequate voice and data systems to their urban customers, local access providers and Incumbent Local Exchanger Carriers (ILEC) need to upgrade the equipment in the local telecommunications cabinets with state of the art equipment, including, but not limited to, Digital Loop Carrier (DLC), and Digital Subscriber Loop systems (xDSL). However, they face a number of problems. The new equipment has greater line density and it requires more power, cooling and space than existing cabinets can provide. The new equipment also emits significantly more electromagnetic radiation than the old equipment and may violate FCC regulations on EMI emissions if run in existing cabinets. In addition, most of the existing or legacy cabinets can only accommodate electronics racks that are twelve inches or less in depth. Some of newer electronics racks are more than thirteen inches in depth and therefore they cannot fit in legacy cabinets. 
     Replacing the existing telecommunications cabinets with new ones designed to accommodate the need for greater line density, and increased power, cooling, space and EMI requirements of the new equipment is a problem too. If a cabinet is removed and replaced, a new right of way is required. This is both costly and time consuming, especially in more densely populated areas like the North Eastern United States, where many municipalities and townships have become significantly more resistant to any form of development. 
     Moreover, if a new cabinet is installed, there has to be continuity of service to existing customers during the installation. In a new installation, this is usually accomplished by first transferring all the lines to a mirror set of telecommunications equipment in a trailer. After the new cabinet is set up, the lines are then all transferred back to the new cabinet. This procedure is both very costly and time consuming. 
     What is needed is a way to utilize the existing cabinets and their existing rights of way, by upgrading the legacy cabinets to be capable of accommodating the new equipment requirements. This upgrade should not only be cost effective, but should preferably be able to be done with minimal disruption of service. 
     SUMMARY OF THE INVENTION 
     The present invention is a cabinet upgrade system for in-service or legacy telecommunications cabinets that improves the existing cabinet&#39;s power, cooling, space and EMI capabilities, thereby allowing the cabinet to be used to house updated telecommunications equipment. 
     In one embodiment, the invention includes an extension collar that fits on the legacy cabinet in place of the legacy doors. The extension collar allows the attachment of replacement doors that have heat exchanger units integrated into them. The extension collar also has suitable flanges to accept Electro-magnetic Interference (EMI) gaskets and so provide EMI shielding capable of meeting standards, such as but not limited to Federal Communications Commission (FCC) mandated levels. The extension collar also has suitable flanges to accept weather or environmental gaskets and so provide protection from the elements. 
     In the preferred embodiment of the invention the replacement doors are heat exchanger doors. The doors have one or more sets of fans, or other air moving means, incorporated into them. The purpose of the fans is to set up two sets of air circulation, one using internal air and one using external air. Both air circulations flow past a common heat-conducting, heat-exchanger partition. By this means heat from within the cabinet is transferred out into the surrounding atmosphere without any exchanger of air and the associated problems of filtering that air exchanger necessitates. 
     Many legacy cabinets are raised off the ground by up to fourteen inches or so. This is done to avoid flooding of the equipment compartment. One embodiment of the invention takes advantage of the resultant space beneath legacy cabinets to accommodate a bulk power upgrade in the form of a battery chamber. As part of the upgrade to the cabinet, a battery chamber is fitted beneath the base of legacy cabinet. Batteries are indifferent to flooding, so long as the water does not reach the terminals, which are located at the top of the battery chambers and close to the base of the legacy equipment compartment base. The heat exchanger doors are constructed to extend down below the base of the cabinet&#39;s equipment compartment and have inlet vents that draw in air from beneath the level of the legacy cabinet equipment compartment base. Furthermore, one of the doors&#39; external air inlets is directed so as to draw air through the upgrade battery cabinet. This allows both cooling and venting of the battery chamber, both of which contribute to longer battery life. Having one door draw external air through the battery chamber while the other draws air in from vents directed away from the chamber ensures that there is enough, but not too much air drawn through the battery compartment. Too much air might result in dust being drawn into the battery compartment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a front and side elevation of a typical legacy telecommunications cabinet. 
     FIG. 2 shows a front and side elevation of a typical legacy cabinet fitted with the upgrade heat exchanger door and battery chamber modules of one embodiment of this invention. 
     FIG. 3 shows a detail view of a portion of the extension collar, including flanges for both electromagnetic interference shielding gasket and weather shielding gaskets. 
     FIG. 4 shows inside views of two types of heat exchanger door including the fan assemblies. 
     FIG. 5 shows the air circulation with a heat exchanger and battery-cooling door of one embodiment of this invention. 
     FIG. 6 shows the air circulation with a non-battery cooling heat exchanger door of this invention. 
     FIG. 7 shows an isometric view of a legacy cabinet having heat exchanger doors replacing all four original, legacy doors. 
     FIG. 8 is a flow chart showing the steps involved in one embodiment of the invention in which a cabinet cooling upgrade is implemented. 
     FIG. 9 is a flow chart showing the steps involved in one embodiment of the invention in which a bulk power conversion is implemented. 
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described with reference to the drawings in which like numbers are used to describe like elements. 
     FIG. 1 shows two elevations of a legacy telecommunications cabinet  10 , having a body  12  and four doors  14 . These cabinets are typically constructed from aluminum or galvanized steel, and have an outer coat of paint. The cabinet body  12  has means for holding and supporting racks of electronic equipment and is raised off the ground-line  18  by end supports  16 . Typical legacy telecommunications cabinet  10  include, but are not limited to, cabinets such as Avaya&#39;s 80C-DP, 80D-DP, 80E-DP, 80A-BP and 80D-BP cabinets as well as similar cabinets made by other telecommunications manufacturers. The cabinets have to be extremely well designed, well manufactured and well installed as they may have to protect electronic equipment against extreme conditions including, but not limited to, hurricanes, fire, tornadoes and seismic vibrations. 
     FIG. 2 shows two elevations of a legacy cabinet  10  in which the legacy doors on one side of the cabinet  10  have been removed and replaced with the extension collar  20  and attached beat-exchanger doors  22  and  24 . In the preferred embodiment of the invention there are two types of heat exchanger door, the heat exchanger and battery cooling door  22  and the heat exchanger only door  24 . Heat exchanger doors  22  and  24  differ in the details of the airflow, as described below and seen by the differing arrangements of air intake grills  28  and air outlet grills  27 . In addition, FIG. 2 shows a battery chamber  26  fitted as an upgrade module underneath the base of legacy cabinet  10 . 
     In many legacy cabinets there is some space available where new equipment can be placed. The existing subscribers can then be transferred to the new equipment once it is installed. If there is no space available, existing batteries can be removed form the equipment compartment and the space freed up used to house the new equipment needed to accommodate existing subscribers. Because the new equipment has higher line densities, existing subscribers can be accommodated in a smaller area of the cabinet. 
     FIG. 3 shows a detailed view of a corner of an extension collar  20  of one embodiment of the invention, showing the flange for the Electromagnetic Interference (EMI) shielding gasket  30 , the EMI shielding gasket  32 , the flange for the weather or environmental gasket  34  and the weather gasket  36 . Modern, high-speed electronics is a significant source of electromagnetic radiation. The EMI gasket is necessary to ensure a conduction seal between the door and the cabinet in order to contain the EMI emission to below FCC mandated levels. The area of the door that interfaces with the EMI gasket does not have paint. This ensures that there is electrical contact between the door and the EMI gasket. The EMI gasket may be made from materials such as, but not limited to, well-known electro-conductive polymers. However, such electro-conductive polymers, while being very effective EMI gaskets, are both expensive and do not hold up well to exposure to water. To protect both the EMI gasket and the components within the cabinet  10  from moisture, the preferred embodiment of the invention includes a weather or environmental gasket flange  34  and an appropriate weather sealing gasket  36 . In one embodiment of the invention, the EMI suppression gasket is only needed on the horizontal portions, i.e. the top and bottom, of the EMI suppression gasket flanges, because the door attachment hinges are mounted on the outer sides of the extension collar and provide sufficient EMI shielding along those joints. 
     FIG. 4 shows the inside of heat exchanger doors  22  and  24  and the fan assemblies  38  and  40 . Fan assemblies  38  and  40  may be suitable air moving device such as, but are not limited to, impeller fans for drawing air in. In the heat-exchanger-and-battery-cooling door  22  both the internal air intake fan unit  38  and the external air intake fan unit  40  are mounted on the same side of the door, thus enabling the external air to be drawn through battery. In contrast, the heat-exchanger-only door  24 , has the internal air intake fan unit  38  mounted so as to draw air in from one side, while the external air intake fan unit (not shown in FIG. 4 for door  24 ) is mounted so as to draw air in from the other side of the same door 
     FIG. 5 is a cross-sectional view of the heat-exchanger-and-battery-cooling door  22 , showing the flow of internal air  44  and the flow of external air  46 . In the preferred embodiment, the internal airflow  44  is driven by impeller fan  38  drawing heated air from the top of the cabinet equipment compartment  45 . This air is then forced down past the inside face of heat-exchanger partition  42 . Heat-exchanger partition  42  is made from a material having good heat conduction, such as but not limited to aluminum, copper or some suitable metal alloy. The heat-exchanger partition  42  may also be shaped to increase the surface area available to the air by for instance, but not limited to, extruding the membrane to have vertical fins, being made of corrugated aluminum sheet or simply being a flat sheet. The internal airflow  44  loses heat through the heat exchanger partition  42  to the external airflow  46 . The internal airflow  44  flows back into the bottom of the cabinet equipment compartment  45 , where it cools the racks of electronics contained in the cabinet. 
     The external airflow  46  is drawn into the door through the battery chamber  26  by external air intake fan unit  40 . In passing through the battery chamber  26 , the external airflow  46  both cools the batteries contained in the battery chamber  26  and vents them, removing any build up of hydrogen or other gases emitted by the batteries. Both the cooling and venting help prolong battery life. Fan unit  40 , which may be, but is not limited to, an impeller fan, then forces the external airflow  46  up past the heat exchanger partition  42 . Airflow  46  cools partition  42  and conveys the heat extracted up through air exit vent  27  into the environment. By this arrangement, the cabinet&#39;s equipment compartment  45  is cooled without any physical exchanger of air or other fluid, obviating any need for filtering and substantially reducing any risk of external contaminants damaging the electronics in the cabinet. 
     FIG. 6 shows the internal airflow  44  and external airflow  46  in a heat exchanger-only door  24  of the preferred embodiment of this invention. As before, the internal airflow  44  is driven by fan unit  38  drawing heated air from the top of the cabinet equipment compartment  45 . This air is then forced down past the inside face of heat exchanger partition  42 . The internal airflow  44  loses heat through the heat exchanger partition  42  to the external airflow  46 . The internal airflow  44  flows back into the bottom of the cabinet equipment compartment  45 , where it cools the racks of electronics contained in the cabinet. The external air flow  46  is drawn in through intake vents  28  by fan unit  40  and forced up passed heat exchanger partition  42 . In passing partition  42 , airflow  46  cools it by extracting heat. Heated airflow  46  then passes out thorough air exit vents  27  back into the surrounding air. The two airflows past the heat exchanger partition cool the telecommunications devices contained in the cabinet equipment compartment  45  without exchanger of air, thereby avoiding the need for filters and their associated maintenance problems. Heat exchangers also substantially reducing the problem of contaminants being introduced into the cabinet during cooling. 
     FIG. 7 shows an isometric view of a legacy cabinet  10  having heat exchanger doors  22  and  24  replacing all four original, legacy doors. FIG. 7 also shows door hinges  48 . In one embodiment of the invention, door hinges  48  obviate the need for EMI shielding gasket  32  on the vertical sections of the EMI shielding gasket flanges  30  (not shown). 
     FIG. 8 is a flow chart showing the steps involved in one embodiment of the invention in which a cabinet cooling upgrade is implemented. Step  1  of the cabinet cooling upgrade is identifying the legacy cabinet&#39;s power capability. The heat exchanger doors of the preferred embodiment of this invention requires at least 6.6 amps of current at 54 V DC and 60 Amp-hr of battery for an 8 hour power reserve. If the legacy cabinet does not have these power capabilities available, then the installer proceeds to or plans for step  3 , the step of performing a bulk power conversion first. 
     Once the legacy cabinet does have adequate power available, the next step in the heat exchanger upgrade process is to determine the specific cabinet type. This determination may be done by for instance, but is not limited to, measuring the legacy cabinet width or some other easily measured dimension. Amongst the common legacy cabinets are, for instance, the Avaya series of cabinets, including the 80C-DP cabinet and the 80D-DP cabinet. These can be distinguished from each other by the fact that the 80C-DP cabinet is 70 ¼ inches in width, while the 80D-DP cabinet is 76 ¼ inches in width. Once the cabinet type is determined, the appropriate Heat Exchanger Door kit can be ordered, delivered and fitted. 
     FIG. 9 is a flow chart showing the steps involved in one embodiment of the invention should a bulk power conversion be implemented. The flow chart of FIG. 9 shows the detailed chain of decisions made with respect to making a bulk power conversion to two specific Avaya cabinets, the 80C-DP cabinet and the 80D-DP cabinet. One of skill in the art will readily appreciate that a similar or related decision chain could be applied to any related cabinet capable of being upgraded in a similar fashion. 
     Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing form the spirit or scope of the invention outlined in the claims appended hereto.