Systems and methods for supplying reduced pressure using a disc pump with electrostatic actuation

A method for operating a disc pump, the method comprising:

• providing the disc pump, the disc pump comprising:
• a pump body having a cylindrical sidewall closed at both ends by a first end wall and a driven end wall to form a cavity for containing a fluid,
• an actuator comprising a conductive layer and operatively associated with the driven end wall to cause an oscillatory motion of the driven end wall at a drive frequency, thereby generating displacement oscillations of the driven end wall in a direction perpendicular thereto,
• a substrate, the driven end wall disposed between the first end wall and the substrate,
• a cylindrical leg structure extending from the cylindrical sidewall and mounted to the substrate, the cylindrical leg structure spacing the substrate from the driven end wall, and
• a conductive plate mounted to the substrate and operatively associated with the actuator and parallel to the actuator;
• applying a drive signal to the conductive plate of the disc pump to cause the conductive plate to switch between a positive charge and a negative charge;
• driving the actuator of the disc pump at a frequency (f) that is equivalent to a resonant frequency of the cavity in response to the positive charge and the negative charge;
• generating displacement oscillations of the actuator in a direction substantially perpendicular thereto;
• and
• generating pressure oscillations of fluid within the cavity to cause fluid flow through a valve of the disc pump, the pressure oscillations corresponding to the displacement oscillations.

A disc pump comprising:

• a pump body having a cylindrical sidewall closed at both ends by a first end wall and a driven end wall to form a cavity for containing a fluid;
• the driven end wall comprises a flexible membrane extending across the cavity, the flexible membrane adapted to hold an electrostatic charge and operative to cause an oscillatory motion of the driven end wall at a drive frequency, thereby generating displacement oscillations of the driven end wall in a direction perpendicular thereto;
• a substrate, the driven end wall disposed between the first end wall and the substrate;
• a cylindrical leg structure extending from the cylindrical sidewall and mounted to the substrate, the cylindrical leg structure spacing the substrate from the driven end wall;
• a conductive plate positioned on the substrate to face the flexible membrane outside of the cavity and adapted to provide an electric field of reversible polarity, the conductive plate being electrically associated with the flexible membrane to cause the flexible membrane to oscillate at the drive frequency in response to reversing the polarity of the electric field;
• a first aperture disposed at any location in the first end wall and extending through the pump body;
• a second aperture disposed at any location in the pump body other than the location of the first aperture and extending through the pump body;
• and
• a valve disposed in at least one of the first aperture and the second aperture;
• whereby the displacement oscillations generate corresponding pressure oscillations of the fluid within the cavity causing fluid flow through the first aperture and the second aperture when in use.