Humidity control system for heat-assisted magnetic recording hard disk drive
A hard disk drive comprises a sensor configured to detect a mixing ratio within the hard disk drive and a membrane electrode assembly. The membrane electrode assembly comprises a gas flow path that couples an inside of the hard disk drive to an outside of the hard disk drive, and the gas flow path includes a cathode and anode that electrolytically remove water vapor from the inside of the hard disk drive. The drive further includes an energy source coupled to the membrane electrode assembly and a controller coupled to the sensor and the energy source. The controller is configured to activate the energy source in response to the sensor detecting a mixing ratio greater than a threshold mixing ratio and to deactivate the energy source in response to the sensor detecting a mixing ratio less than the threshold mixing ratio.
1. A hard disk drive, comprising:
a sensor configured to detect a humidity mixing ratio within the hard disk drive, wherein the sensor is configured to continuously detect the humidity mixing ratio during operation of the hard disk drive;
a membrane electrode assembly comprising a gas flow path that couples an inside of the hard disk drive to an outside of the hard disk drive, the gas flow path comprising a cathode and anode that electrolytically remove water vapor from the inside of the hard disk drive;
an energy source coupled to the membrane electrode assembly; and
a controller coupled to the sensor and the energy source, the controller configured to activate the energy source in response to the sensor detecting a humidity mixing ratio greater than a threshold humidity mixing ratio and to deactivate the energy source in response to the sensor detecting a humidity mixing ratio less than the threshold humidity mixing ratio.
2. The hard disk drive of claim 1 , wherein the gas flow path comprises, in order from the inside of the hard disk drive to the outside of the hard disk drive:
a hydrophilic first membrane;
the anode;
an electrolyte second membrane;
the cathode; and
a hydrophobic third membrane.
3. The hard disk drive of claim 2 , wherein the electrolyte second membrane comprises a solid polymer.
4. The hard disk drive of claim 1 , wherein the membrane electrode assembly is integrated into a portion of an enclosure of the hard disk drive.
5. The hard disk drive of claim 1 , wherein the threshold is 10 g/Kg.
6. The hard disk drive of claim 1 , wherein the hard disk drive is configured for heat-assisted magnetic recording.
7. The hard disk drive of claim 1 , wherein the controller is disposed within the hard disk drive.
8. The hard disk drive of claim 1 , wherein the energy source is disposed within the hard disk drive.
9. The hard disk drive of claim 1 , wherein the sensor is disposed within the hard disk drive.
10. The hard disk drive of claim 1 , further comprising a temperature sensor.
11. The hard disk drive of claim 1 , wherein the sensor detects temperature within the hard disk drive.
12. A hard disk drive, comprising:
a sensor configured to detect humidity within the hard disk drive, wherein the sensor is configured to continuously detect the humidity during operation of the hard disk drive;
a membrane electrode assembly comprising a gas flow path that couples an inside of the hard disk drive to an outside of the hard disk drive, the gas flow path comprising a cathode and anode that electrolytically remove water vapor from the inside of the hard disk drive;
an energy source coupled to the anode and the cathode of the membrane electrode assembly; and
a controller coupled to the sensor and the energy source, the controller configured to activate the energy source in response to the sensor detecting a humidity greater than a first threshold humidity and to deactivate the energy source in response to the sensor detecting a humidity less than a second threshold humidity.
13. The hard disk drive of claim 12 , wherein the sensor detects humidity as a mixing ratio.
14. The hard disk drive of claim 12 , wherein the sensor detects humidity as relative humidity.
15. The hard disk drive of claim 12 , wherein the first threshold humidity is the same as the second threshold humidity.
16. A method, comprising:
detecting a first humidity by a sensor within a hard disk drive, wherein the sensor continuously detects humidity within the hard disk drive during operation of the hard disk drive;
in response to the first humidity being greater than a threshold humidity, activating an energy source coupled to a membrane electrode assembly integrated into the hard disk drive and comprising a gas flow path that couples an inside of the hard disk drive to an outside of the hard disk drive;
electrolytically removing water vapor from the inside of the hard disk drive via the membrane electrode assembly;
detecting a second humidity by the sensor within the hard disk drive; and
in response to the second humidity being less than the threshold humidity, deactivating the energy source.
17. The method of claim 16 , wherein the energy source is repeatedly activated and deactivated in response to the sensor detecting a humidity respectively greater and less than the threshold humidity during operation of the hard disk drive for a closed loop control of the membrane electrode assembly.