OUTDOOR COMMUNICATION CABINET INCLUDING FAN TRAY AND FILTER AND METHOD OF DETECTING BLOCKAGE OF COMMUNICATION CABINET FILTER

1 . An outdoor communication cabinet comprising:

a housing having a interior and an opening into said interior;

a door connected to said housing at the opening and including a first aperture; and

a first fan tray, including a plurality of fans, hingedly connected to said door for movement between first and second positions relative to said first aperture.

2 . The outdoor communication cabinet of claim 1 , wherein said door includes a second aperture adjacent said first aperture and further includes either a second fan tray, including a plurality of fans, hingedly connected to said door for movement between first and second positions relative to said second aperture independently of said first fan tray, or a panel removably mounted over said second aperture.

3 . The outdoor communication cabinet of claim 1 , including a second fan tray hingedly connected to said door for movement between first and second positions relative to said first aperture independently of said first fan tray.

4 . The outdoor communication cabinet of claim 1 , wherein said first fan tray is mounted in a fan box, said fan box being connected to the door by a hinge, said fan box comprising a frame configured to support said first fan tray and at least one filter.

5 . The outdoor communication cabinet of claim 4 , wherein said fan box includes a first peripheral wall within said frame configured to sealingly engage a first filter and a second peripheral wall spaced from said first peripheral wall configured to sealingly engage a second filter.

6 . The outdoor communication cabinet of claim 5 , including a first filter retained in sealing engagement with said first wall by said fan box frame, a second filter retained in sealing engagement with said second wall by said fan box frame, and a gasket forming a seal between said fan tray and said fan box frame.

7 . The outdoor communication cabinet of claim 4 , wherein said door includes an outer panel and an inner panel spaced from the outer panel and defining a space therebetween, said first aperture being located in said inner panel and said fan box being mounted to said inner panel and extending through said first aperture and into said space.

8 . The outdoor communication cabinet of claim 1 including a controller for controlling said plurality of fans of said first fan tray based on a sensed condition and a pressure sensor in said cabinet operatively connected to said controller.

9 . The outdoor communication cabinet of claim 1 , including a damper for regulating a size of an exit hole in said housing and a controller for controlling said plurality of fans of said first fan tray and a position of said damper.

10 . The outdoor communication cabinet of claim 8 , wherein said controller is configured to measure a first output of said pressure sensor when said plurality of fans of said first fan tray are in a first state, to measure a second output of said pressure sensor when said plurality of fans of said first fan tray are in a second state, and to generate a signal when a difference between said first output and said second output satisfies a predetermined condition.

11 . A method of detecting a degree of blockage of a filter in an outdoor communication cabinet, the cabinet comprising 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, said method comprising:

providing a sensor in the housing configured to provide an output based on a sensed pressure of the housing;

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.

12 . The method of claim 11 wherein the relationship comprises a difference between the first level and the second level and wherein the predetermined condition comprises the difference being less than a predetermined amount.

13 . The method of claim 11 , further including:

determining a third level of the output when the filter is clean and the at least one fan is in the first state;

determining a fourth level of the output when the filter is clean and the at least one fan is in the second state; and

using a difference between the third level and the fourth level to establish the predetermined condition.

14 . The method of claim 11 wherein the first state comprises the at least one fan being off and wherein the second state comprises the at least one fan being on and operating at less than full power.

15 . The method of claim 11 , wherein the at least one fan comprises a plurality of fans in a fan tray and wherein the housing includes a fan box having a frame for supporting the fan tray and at least one filter, the method including forming a seal between the fan tray and the fan box and mounting the at least one filter in sealing engagement with a portion of the frame such that substantially all air drawn through the fan tray by the plurality of fans is filtered by the at least one filter.

16 . An outdoor communication cabinet comprising:

a housing having a interior and a first opening and a second opening into said interior;

a door connected to said housing at said first opening;

a fan tray, including a plurality of fans, connected to said door;

a damper mounted at said second opening for regulating air flow through said second opening; and

a controller operatively connected to said plurality of fans and to said damper for controlling operation of said plurality of fans and a position of said damper.

17 . The outdoor communication cabinet of claim 16 wherein said door includes an aperture and wherein said first fan tray is hingedly connected to said door for movement between a first position and a second position relative to said first aperture.

18 . The outdoor communication cabinet of claim 16 including a temperature sensor operatively connected to said controller, wherein said controller controls a position of said damper based on a temperature sensed by said temperature sensor.

19 . The outdoor communication cabinet of claim 18 wherein said controller causes said damper to close when said temperature sensor senses a temperature less than a first predetermined temperature and causes said damper to open when said temperature sensor senses a temperature greater than a second predetermined temperature.

20 . The outdoor communication cabinet of claim 12 , wherein said first fan tray is mounted in a fan box, said fan box being connected to the door by a hinge, said fan box comprising a frame configured to support said first fan tray and at least one filter; and

a pressure sensor for sensing a pressure of the interior operatively connected to said controller;

wherein said controller is configured to measure a first output of said pressure sensor when said plurality of fans of said fan tray are in a first state, to measure a second output of said pressure sensor when said plurality of fans of said fan tray are in a second state, and to generate a signal when a relationship between said first output and said second output satisfies a predetermined condition.

21 . A method of detecting a degree of blockage of a filter in an outdoor communication cabinet, the cabinet comprising a housing having an interior and a first opening and a second opening into the interior, a door connected to the housing at the opening and including an aperture, a fan tray, including a plurality of fans, hingedly connected to the door for movement between first and second positions relative to the first aperture, a damper mounted at the second opening for regulating air flow through the second opening, and a controller 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 filter being mounted to said door over said aperture on a side of said first fan tray opposite from said interior, said method comprising:

providing a pressure sensor in the housing configured to provide an output based on a sensed pressure of the housing;

connecting the pressure sensor to the controller;

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.