Patent Application
20110086589
The present invention is directed toward an improved outdoor communication cabinet for housing heat-producing electronic equipment that includes a fan tray and a filter and toward a method of detecting blockage of a communication cabinet filter, and, more specifically, toward an outdoor communication cabinet for electronic equipment that includes a door-mounted fan tray, a door-mounted filter for filtering air drawn into the cabinet by fans in the fan tray and a controller for controlling the fans and for detecting blockage of the filter.
Outdoor cabinets for electronic and/or telecommunication equipment and connection panels are known in the art. The equipment in these cabinets generally must be maintained within a certain temperature range in order to function properly, and some of this equipment generates heat that must be dissipated. Direct air cooling is a common method for removing excess heat from such cabinets, especially when the equipment in the cabinet generates a relatively large amount of heat. In such systems, vents are also provided for allowing heat to escape from the cabinet interior and for allowing an air flow to pass through the cabinet over and around the equipment, which air flow may be produced or assisted by one or more fans. Screens or filters may also be provided to reduce the amount of particulate matter that finds its way into the cabinet interior, and any vent openings may be louvered to protect the cabinet interior from rain.
These outdoor cabinets may require periodic inspection to determine whether filters require replacement and whether the fan or fans in the cabinet are working properly. Filters that have become blocked may reduce air flow through the cabinet sufficiently that equipment in the cabinet overheats and malfunctions and may also lead to premature fan failure which further reduces the cooling capacity of the cabinet. It would therefore be desirable to determine automatically when a filter has become blocked and to mount one or more filters and the fan or fans in a manner that facilitates service and/or replacement when necessary and to permit scaling of the cooling system as need by the addition, deletion or changing of equipment in the cabinet.
These problems and others are addressed by embodiments of the present invention, a first aspect of which comprises an outdoor communication cabinet having a housing with a interior and an opening into the interior. A door is connected to the housing at the opening and includes a first aperture. A first fan tray, including a plurality of fans, is hingedly connected to the door for movement between first and second positions relative to the first aperture.
Another aspect of the invention comprises a method of detecting a degree of blockage of a filter in an outdoor communication which cabinet which includes a housing and at least one fan for driving air into the housing and a filter for filtering the air driven into the housing by the at least one fan. The method includes providing a sensor in the housing that provides an output based on a sensed pressure of the housing. The method also includes determining a first level of the output when the at least one fan is in a first state and determining a second level of the output when the at least one fan is in a second state. A relationship is determined between the first level and the second level and a signal is generated when the relationship satisfies a predetermined condition.
A further aspect of the invention comprises an outdoor communication cabinet that includes a housing with a interior and first and second openings into the interior. A door is connected to the housing at the first opening, and a fan tray, including a plurality of fans, is connected to the door. A damper is mounted at the second opening for regulating air flow through the second opening, and a controller is operatively connected to the plurality of fans and to the damper for controlling operation of the plurality of fans and a position of the damper.
Yet another aspect of the invention comprises a method of detecting a degree of blockage of a filter in an outdoor communication cabinet. The cabinet includes a housing having an interior with first and second openings into the interior, and a door is connected to the housing at the opening. The door includes an aperture, and a fan tray including a plurality of fans is hingedly connected to the door for movement between first and second positions relative to the first aperture. The filter is mounted to the door over the aperture on a side of the first fan tray opposite from the interior. A damper is mounted at the second opening for regulating air flow through the second opening, and a controller is operatively connected to the plurality of fans and to the damper for controlling operation of the plurality of fans and a position of the damper. The method includes providing a pressure sensor in the housing configured to provide an output based on a sensed pressure of the housing and connecting the pressure sensor to the controller. The method also includes determining a first level of the output when the at least one fan is in a first state, determining a second level of the output when the at least one fan is in a second state, determining a relationship between the first level and the second level, and generating a signal when the relationship satisfies a predetermined condition.
These and other aspects and features of the invention will be better understood after a reading of the following detailed description together with the attached drawings, wherein:
The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as “between X and Y” and “between about X and Y” should be interpreted to include X and Y. As used herein, phrases such as “between about X and Y” mean “between about X and about Y.” As used herein, phrases such as “from about X to Y” mean “from about X to about Y.”
It will be understood that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.
Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “lateral”, “left”, “right” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the descriptors of relative spatial relationships used herein interpreted accordingly.
A cabinet 10 according to an embodiment of the present invention is illustrated in
Referring now to
A first filter 66 is mounted in a space 68 between first peripheral wall 64 and second peripheral wall 64, and space 68 is selected based on the size of the filter to be used to provide a snug fit for the filter so that substantially all air passing through fan box 44 must pass through first filter 66. First filter 66 is inserted into space 68 through a side entrance 70, illustrated in
A second filter 72 is mounted on the side of second peripheral wall 64 opposite first filter 66 and is held against the second peripheral wall 64 by a fan tray 74 mounted on the rear side 56 of the fan box 44. Second filter 72 comprises a hydrophobic filter configured to substantially prevent the passage of particulate matter that is not trapped by first filter 66 and likewise to substantially prevent water from entering cabinet 10 through fan box 44. A suitable hydrophobic filter is an ePTFE (Expanded Polytetrafluoroethylene) based filter available from W. L. Gore & Associates. Second filter 72 will generally be more expensive than first filter 66, but because second filter 72 filters air that has already been filtered by first filter 66, it will require less frequent cleaning or replacement. Second filter 72, as illustrated in
Fan tray 74 comprises a panel 80 having a first side 82 facing second filter 72 and a second side 84 facing housing interior 16 when door 18 is closed. A plurality of fans 86 are mounted in openings in panel 80 and connected to a suitable controller 88, illustrated in
The removal of first filter 66 and second filter 72 for cleaning or replacement and the removal of fan tray 74 for repair will now be described. With reference to
Fan tray 74 is mounted to rear side 56 of fan box frame 48, and is readily accessible when door 18 of cabinet 10 is opened. If fan tray 74 or one or more fans 86 on the fan tray 74 require service, they can be directly accessed by opening cabinet door 18. Alternately, fan tray 74 can be removed and replaced with a new fan tray when it is preferable to quickly return the cabinet 10 to service and troubleshoot the defective fan tray at a service facility rather than in the field.
An exit opening 96 is provided on a wall of housing spaced from door 18, such as rear wall 98 illustrated in
Controller 88 controls the position of damper flaps 102 based at least in part on input from temperature sensor 94. When the interior temperature of housing 12 exceeds a predetermined temperature, 5 degrees C., for example, controller 88 causes actuator 104 to open flaps 102. When the temperature of the housing interior drops below 5 degrees C., controller 88 closes flaps 102 to retain heat and reduce the need for auxiliary heating of the cabinet. The fans 86 may be turned on and off and operated at different speeds based on the sensed temperature of the housing in a conventional manner.
A method of determining when first filter 66 and/or second filter 72 needs service is also possible with the cabinet 10 described above. According to this method, a first pressure reading is taken by pressure sensor 92 when the fans 86 are in a first operating state, such as off. The fans 86 are then driven at a set speed, such as 60% of their maximum operating speed, and a second pressure reading is taken. The difference between these readings is compared to a predetermined value, and if the difference is less than the predetermined value, a signal is generated by controller 88 to indicate that the filters are at least partially blocked and require service. The predetermined amount may be established from baseline readings taken when first filter 66 and second filter 72 are new. For example, it may be possible to raise the pressure inside housing 12 by 2 psi by running the fans 86 at 60% of their maximum rate when the filters are not blocked. As the first and second filters become increasingly blocked with use, the fans 86 will not be able to draw in air at a high enough rate to increase the pressure in the housing by the same amount. When, for example, the pressure can no longer be raised by 1 psi, it may be time to service the filters. The actual amounts of pressure increase indicative of clean filters and filters that require service can be determined empirically for a particular installation, and controller 88 can run this test on a predetermined basis, daily, for example. A variety of different first and second fan operating states can be selected for performing the above test, such as 10 percent of maximum operating speed for the first state and 80 percent of maximum operating speed for the second test. However, it may be desirable to select a second state that is low enough, such as the 60% of maximum operating speed described above, to avoid the production of excessive turbulence inside the housing which can make it difficult to obtain an accurate pressure reading.
A method related to the above method is illustrated in the flow chart of
The present invention has been described in terms of preferred embodiments. However, modifications and additions to these embodiments will become apparent to those of ordinary skill in the relevant art upon a review of the foregoing disclosure. It is intended that all such modifications and additions comprise a part of the present invention to the extent they fall within the scope of the several claims appended hereto.
The present application claims the benefit of U.S. Provisional Patent Application No. 61/251,506 filed Oct. 14, 2009, the entire contents of which is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61251506 | Oct 2009 | US |
