Filter system for electronic equipment enclosure
View Patent ↗A filter system including a method for self cleaning the filter system of an electronic equipment enclosure where air flow is monitored either by monitoring fan performance of air flow velocity through the enclosure. The system includes two filters elements, an upstream ASHRAE or HEPA filter element to block particulate matter and a downstream PTFE filter element to block water vapor. The ASHRAE or HEPA filter element is relatively inexpensive and easy to clean. The PTFE filter element is more expensive and difficult to clean. Thus, the cheaper filter is used to protect the more expensive filter from contaminants and to increase its useful life. The method of self cleaning includes stopping the fan when a signal is received indicating a predetermined resistance to air flow which is a function of blockage of the filter elements, thereafter operating the fan at an increased rotational velocity to determine whether the fan itself is malfunctioning, thereafter slowing and stopping the fan to allow the fan to be reversed, rotating the fan in reverse for a predetermined period of time, such as five minutes, thereafter slowing and stopping the fan and returning the fan to its usual rotational velocity and direction. If the resistance to air flow is still above a predetermined level, the fan is again slowed, stopped and reversed and then returned to normal operation. The reversal operation can be conducted a multiple number of times, however, after a predetermined number, a signal is sent requesting maintenance.
1. A method of using an electronic equipment enclosure having indoor grade electronics in an outdoor environment, the electronic equipment enclosure including an inlet, an outlet, an air flow path extending through the electronic equipment enclosure from the inlet to the outlet, a vapor filter positioned in the air flow path, and a separate, removable particle filter positioned in the air flow path upstream of the vapor filter, the method comprising:
installing the electronic equipment enclosure in an outdoor environment;
intaking ambient air from the outdoor environment into the air flow path via the inlet; and
exhausting the ambient air from the air flow path via the outlet, the ambient air passing through the particle filter before passing through the vapor filter to remove particles from the ambient air before the ambient air reaches the vapor filter, the particle filter thereby protecting and extending the useful life of the vapor filter.
2. The method of claim 1 wherein the particle filter is one of an ASHRAE filter and a HEPA filter, and the vapor filter is a PTFE filter.
3. The method of claim 1 wherein the electronic equipment enclosure includes a fan.
4. The method of claim 3 wherein the electronic equipment enclosure includes a controller for controlling the fan.
5. The method of claim 4 wherein the controller is configured to change the fan's direction of rotation.
6. The method of claim 5 wherein the controller is configured to change the fan's velocity.
7. The method of claim 5 wherein the electronic equipment enclosure includes a sensor for monitoring air flow resistance, and wherein the controller is responsive to the sensor.
8. The method of claim 7 wherein the electronic equipment enclosure is configured to change the direction and/or velocity of the fan based on the sensed air flow resistance.
9. The method of claim 1 wherein the particle filter is positioned for easier access than the vapor filter.
10. The method of claim 1 further comprising removing the particle filter for cleaning or replacing the particle filter.
11. The method of claim 1 further comprising replacing the particle filter and the vapor filter.
12. A method of intaking air into an electronic equipment enclosure, the electronic equipment enclosure including an inlet housing, the inlet housing including a vapor filter and a separate, removable HEPA filter and a vapor filter, the HEPA filter being upstream from the vapor filter, the method comprising positioning the electronic equipment enclosure in an outdoor environment such that air flows from the outdoor environment through the HEPA filter before the vapor filter.
13. The method of claim 12 wherein the electronic equipment enclosure includes indoor grade electronic components.
14. The method of claim 12 wherein the electronic equipment enclosure includes an exhaust fan for facilitating air flow through the HEPA filter and the vapor filter.
15. The method of claim 13 wherein the exhaust fan is configured to change direction and/or velocity.
16. The method of claim 15 wherein the exhaust fan is responsive to a sensor monitoring resistance to air flow.
17. A method of intaking outdoor air into an electronic equipment enclosure, the electronic equipment enclosure including indoor grade electronics, at least one power module, an inlet housing and a outlet housing, the inlet housing including a removable particle filter, a vapor filter and louvers, the vapor filter positioned downstream of the particle filter and the louvers, the outlet housing including an exhaust fan, the method comprising installing the electronic equipment enclosure in an outdoor environment such that the exhaust fan facilitates air flow from the outdoor environment through the louvers, the particle filter and the vapor filter into an interior of the electronic equipment enclosure.