Patent application title: Method And System For Cleaning A Fan Inlet
Inventors:
Richard A. Kominsky (Westfield, MA, US)
Assignees:
ITT MANUFACTURING ENTERPRISES, INC.
IPC8 Class: AF04B4906FI
USPC Class:
417 442
Class name: Condition responsive control of pump drive motor by control of electric or magnetic drive motor responsive to pump fluid pressure
Publication date: 2012-09-20
Patent application number: 20120237363
Abstract:
A system includes a housing; a first fan having a first inlet and a
second fan having a second inlet, the first fan and the second fan
mounted in a wall of the housing, the first fan and the second fan
oriented to draw air into the housing; a device in the housing, the
device positioned to receive airflow from the first fan and the second
fan; and a controller for controlling the first fan and the second fan,
wherein the controller is configured to initiate a cleaning cycle during
which the first fan is on and the second fan is off to cause backpressure
airflow to flow through the second inlet in a reverse direction for a
first time period and the first fan is off and the second fan is on to
cause backpressure airflow to flow through the first inlet in a reverse
direction for a second time period.Claims:
1. A system comprising: a housing; a first fan having a first inlet and a
second fan having a second inlet, the first fan and the second fan
mounted in a wall of the housing, the first fan and the second fan
oriented to draw air into the housing; a device in the housing, the
device positioned to receive airflow from the first fan and the second
fan; and a controller for controlling the first fan and the second fan,
wherein the controller is configured to initiate a cleaning cycle during
which the first fan is on and the second fan is off to cause backpressure
airflow to flow through the second inlet in a reverse direction for a
first time period and the first fan is off and the second fan is on to
cause backpressure airflow to flow through the first inlet in a reverse
direction for a second time period.
2. The system of claim 1 wherein: the first inlet is a mesh.
3. The system of claim 1 wherein: the first inlet is a filter.
4. The system of claim 1 wherein: the device includes a heat sink.
5. The system of claim 4 wherein: the device includes a voltage regulator component.
6. The system of claim 5 wherein: the voltage regulator component is part of a motor vehicle electrical system that converts AC voltage from an alternator to DC voltage.
7. The system of claim 6 wherein: wherein the DC voltage is 28 VDC.
8. A method of cooling a device comprising: providing a housing; providing a first fan having a first inlet and a second fan having a second inlet, the first fan and the second fan mounted in a wall of the housing, the first fan and the second fan oriented to draw air into the housing; providing a device in the housing, the device positioned to receive airflow from the first fan and the second fan; and providing a controller for controlling the first fan and the second fan, wherein the controller is configured to initiate a cleaning cycle during which the first fan is on and the second fan is off to cause backpressure airflow to flow through the second inlet in a reverse direction for a first time period and the first fan is off and the second fan is on to cause backpressure airflow to flow through the first inlet in a reverse direction for a second time period.
9. The method of claim 8 wherein: the first inlet is a mesh.
10. The method of claim 8 wherein: the first inlet is a filter.
11. The method of claim 8 wherein: the device includes a heat sink
12. The method of claim 1 wherein: the device includes a voltage regulator component.
13. The method of claim 12 wherein: the voltage regulator component is part of a motor vehicle electrical system that converts AC voltage from an alternator to DC voltage.
14. The method of claim 13 wherein: wherein the DC voltage is 28 VDC.
Description:
BACKGROUND OF THE INVENTION
[0001] Fans are used in a number of applications to keep electrical components cool. In a conventional fan inlet, a mesh or filter is placed in front of the fan air intake to collect dirt and remove dirt from the air stream prior to the air being blown into the device being cooled. The inlet retains the dirt to protect the device being cooled. During normal operation, the inlet (e.g., mesh or filter) retains dirt and becomes partially blocked. As the quantity of dirt increases, passages through the inlet are reduced to a point where the airflow is ineffective for cooling the device. There is a need in the art for a system that regularly cleans fan inlets to maintain airflow.
BRIEF SUMMARY OF THE INVENTION
[0002] An exemplary embodiment of the invention is system comprising a housing; a first fan having a first inlet and a second fan having a second inlet, the first fan and the second fan mounted in a wall of the housing, the first fan and the second fan oriented to draw air into the housing; a device in the housing, the device positioned to receive airflow from the first fan and the second fan; and a controller for controlling the first fan and the second fan, wherein the controller is configured to initiate a cleaning cycle during which the first fan is on and the second fan is off to cause backpressure airflow to flow through the second inlet in a reverse direction for a first time period and the first fan is off and the second fan is on to cause backpressure airflow to flow through the first inlet in a reverse direction for a second time period.
[0003] Another exemplary embodiment of the invention is a method of providing a housing; providing a first fan having a first inlet and a second fan having a second inlet, the first fan and the second fan mounted in a wall of the housing, the first fan and the second fan oriented to draw air into the housing; providing a device in the housing, the device positioned to receive airflow from the first fan and the second fan; and providing a controller for controlling the first fan and the second fan, wherein the controller is configured to initiate a cleaning cycle during which the first fan is on and the second fan is off to cause backpressure airflow to flow through the second inlet in a reverse direction for a first time period and the first fan is off and the second fan is on to cause backpressure airflow to flow through the first inlet in a reverse direction for a second time period.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 depicts a system for cleaning a fan inlet in exemplary embodiments.
[0005] FIG. 2 is a flowchart of a process for cleaning a fan inlet in exemplary embodiments.
[0006] FIG. 3 depicts the system of FIG. 1 with one fan shut off in exemplary embodiments.
DETAILED DESCRIPTION
[0007] FIG. 1 depicts a system for cleaning a fan inlet in exemplary embodiments. The system 100 includes a housing 102. The housing 102 may partially or completely contain the elements depicted in FIG. 1. Within housing 102 is a voltage regulator 104, or alternatively components of a voltage regulator requiring cooling. In exemplary embodiments, the voltage regulator 104 is part of a motor vehicle electrical system that converts AC voltage from an alternator to DC voltage (e.g., 28 VDC). As the regulator 104 handles substantial power, a heat sink 106 is in thermal contact with regulator 104 to dissipate heat. Heat sink 106 may be coupled to regulator 104 using known heat transfer media (e.g., thermally conductive adhesive).
[0008] Two fans 1101 and 1102 are mounted in a wall of the housing 102 to draw air from outside the housing. Although two fans are shown in FIG. 1, it is understood that embodiments may be implemented using more than two fans. Each fan 110 includes an inlet 1121 and 1122. The inlets 112 may be a mesh or a filter (e.g. HEPA filter), designed to trap particulates to prevent the particulates from entering housing 102. The outlet from each fan 110 is directed at heat sink 106 to assist in cooling the regulator 104. Airflow exits the housing 102 through vents in one of the sidewalls of the housing.
[0009] A driver 130 controls the fans 110 by providing drive signals to fans 110. The drive signals may be any known type of electrical signals (e.g., DC, PWM), and will depend on the nature of the motors in fans 110. A separate driver may be used for each fan 110, although a single driver 130 is shown in FIG. 1 for simplicity.
[0010] A controller 132 provides control signals to the driver 130 to control speed and direction of fans 110. The controller 132 may be implemented using known processor-based devices (e.g., a general purpose microprocessor executing code), hardware, a combination of hardware and software, ASICs, etc. As described herein, controller 132 controls fans 110 so that the fan inlets 112 are periodically cleaned of particulates.
[0011] FIG. 2 is flowchart of an exemplary process for cleaning the fan inlets 112. The process begins at block 200 where the system of FIG. 1 is powered on. When powered on, controller 132 executes the fan cleaning cycle. At block 202, controller 132 generates control signals to driver 130 to generate drive signals turning fan 1101 on and fan 1102 off for a predetermined period of time (e.g., 5 minutes). FIG. 3 illustrates fan 1101 on and 1102 off. In this state, the backpressure from heat sink 106 forces some airflow to flow through fan 1102, through inlet 1122 and out of the housing 102. This reverse airflow forces particulates out of inlet 1122 effectively cleaning the inlet 1122.
[0012] After a predetermined amount of time, flow proceeds to block 204 where controller 132 generates control signals to driver 130 to generate drive signals turning fan 1101 off and fan 1102 on for a predetermined period of time (e.g., 5 minutes). This is the opposite of the mode shown in FIG. 3, and results in the backpressure airflow from heat sink 106 to flow through fan 1101 and inlet 1121 and out of the housing 102. Once the predetermined amount of time has passed, the process flows to 206 where the controller 132 operates fans 110 in a normal operation mode. This may entail running both fans at steady or variable speeds based on sensed conditions.
[0013] The controller 132 can re-initiate the cleaning cycle of blocks 202 and 204 after a time interval has lapsed. The process in FIG. 2 includes block 208, where a determination is made if a time interval (e.g., a number of hours) has lapsed. If not, the controller 132 continues to operate in normal mode at block 206. If a time interval has lapsed, the process loops back to block 202 to perform the cleaning cycle again. The embodiments described above provide for cleaning of fan inlets without requiring reversal of fan direction.
[0014] While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed for carrying out the invention, but that the invention will include all embodiments falling within the scope of the appended claims.
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