Method for detecting the cleanliness of a filter

• US 20050188842A1
• Filed: 02/23/2005
• Published: 09/01/2005
• Est. Priority Date: 02/26/2004
• Status: Active Grant

• Current Assignee: Qisda Corporation
• Original Assignee: Qisda Corporation
• Inventors: Wei, Hung-Jen, Hsieh, Chia-Chang
• Granted Patent: US 7,445,665 B2
• Time in Patent Office: Days
• US Class Current: 95/25
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: B01D 46/444 by flow measuring

Abstract

A method for detecting the cleanliness of a filter. The filter is disposed on an air inlet or an air outlet of a fan. The method includes the following steps. At first, outputting a rotation control voltage to the fan, and an airflow generated by the rotation of the fan flows through the filter. Then, detect an actual rotation rate of the fan, and calculate an actual dust value f1 according to the actual rotation rate and the rotation rate control voltage. Then, a dust upper limit value of the filter is defined. Finally, the cleanliness of the filter is determined according to the actual dust value and the dust upper limit value.

Claims

1. A method for detecting a cleanliness of a filter, the filter being disposed on an air inlet or an air outlet of a fan, the method comprising:

outputting a rotation control voltage to the fan, wherein an airflow generated by the rotation of the fan flows through the filter;

detecting an actual rotation rate of the fan;

calculating an actual dust value f1 according to the actual rotation rate and the rotation control voltage;

providing a dust upper limit value fm of the filter; and

determining the cleanliness of the filter according to the actual dust value f1 and the dust upper limit value fm.

2. The method according to the claim 1, wherein the step of determining the cleanliness further comprises:

sending a warning signal of excess dust when the actual dust value f1 is larger than or equal to the dust upper limit value fm.

3. The method according to the claim 1, wherein the step of determining the cleanliness further comprises:

sending a warning signal of excess dust when the actual dust value f1 is larger than the dust upper limit value fm.

4. The method according to the claim 1, wherein the step of determining the cleanliness further comprises:

sending a warning signal to remind that the filter needs to be cleaned when the actual dust value f1 is larger than the dust upper limit value fm.

5. The method according to the claim 1, wherein the step of determining the cleanliness further comprises:

sending a warning signal to remind that the filter needs to be cleaned when the actual dust value f1 is larger than or equal to the dust upper limit value fm.

6. The method according to the claim 5, wherein the warning signal is a lamp signal.

7. The method according to the claim 5, wherein the warning signal is a sound.

8. The method according to the claim 5, wherein the filter is disposed in an electronic device, the warning signal is an on screen display (OSD) signal of the electronic device.

9. The method according to the claim 1, wherein the rotation control voltage corresponds to a pre-set rotation rate.

10. The method according to the claim 1, wherein the actual dust value f1 is the ratio of actual rotation rate to the rotation control voltage.

11. The method according to the claim 1, wherein the actual dust value f1 is calculated according to the steps below:

converting the detected actual rotation rate to a rotation pulse frequency; and

calculating the ratio of the rotation pulse frequency to the rotation control voltage to generate the actual dust value f1.

12. The method according to the claim 1, wherein the dust upper limit value fm is obtained according to the rotation control voltage and a default value table.

13. The method according to the claim 12, wherein the default value table is calculated according to the steps below:

recording the rotation control voltage inputted to the fan when the filter has a pre-set dust upper limit value;

detecting the actual rotation rate of the fan;

calculating a corresponding ratio of the actual rotation rate to the rotation control voltage to obtain the dust upper limit value fm corresponding to the rotation control voltage; and

calculating the ratio of each rotation control voltage to the corresponding actual rotation rate to record as the default value table under different rotation control voltages.