# US 9,752,565 B2 · Systems and methods for supplying reduced pressure using a disc pump with electrostatic actuation

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- Number: US 9,752,565 B2
- Document ID: US9752565B2
- Status: Granted
- Kind: B2
- Application number: 13/935,000
- Filed: 2013-07-03
- Published: 2014-01-09
- Granted: 2017-09-05
- Earliest claimed: 2012-07-05
- Assignees: KCI Licensing, Inc.
- Applicants: KCI Licensing, Inc.
- Inventors: Christopher Brian Locke; Aidan Marcus Tout
- Web page: https://patentgrep.com/patent/US9752565B2

## CPC

- F04B 43/04: Pumps having electric drive
- F04B 45/047: Pumps having electric drive
- F04F 7/00: Pumps displacing fluids by using inertia thereof, e.g. by generating vibrations therein
- F04F 7/02: Hydraulic rams
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- F04F: PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED {(evacuating by sorption F04B)}; SIPHONS {(conveying materials in bulk by flows of gas, liquid of foam B65G53/00)}

## Abstract

A disc pump includes a pump body having a cavity for containing a fluid. The disc pump also includes an actuator adapted to hold an electrostatic charge to cause an oscillatory motion at a drive frequency. The disc pump further includes a conductive plate positioned to face the actuator outside of the cavity and adapted to provide an electric field of reversible polarity, the conductive plate being electrically associated with the actuator to cause the actuator to oscillate at the drive frequency in response to reversing the polarity of the electric field. The disc pump further includes a valve disposed in at least one of a first aperture and a second aperture in the pump body. The oscillation of the actuator at the drive frequency causes fluid flow through the first aperture and the second aperture when in use.

## Claims

### Claim 1

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 consists essentially of 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 first conductive plate positioned to face the flexible membrane outside of the cavity and adapted to provide an electric field of reversible polarity, the first 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 second conductive plate positioned on an opposite side of the flexible membrane from the first conductive plate, the second conductive plate adapted to provide an electric field of reversible polarity and 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 of the second conductive plate, the electric field of the second conductive plate further adapted to have an opposite polarity to the electric field of the first conductive plate;
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.

### Claim 2 (depends on 1)

The disc pump of claim 1, wherein the flexible membrane comprises a dielectric membrane.

### Claim 3 (depends on 1)

The disc pump of claim 1, further comprising a drive circuit, wherein the first conductive plate and the second conductive plate are operable to receive a drive signal from the drive circuit and switch from a positive charge to a negative charge in response to the receiving the drive signal.

### Claim 4 (depends on 3)

The disc pump of claim 3, wherein the flexible membrane comprises a dielectric membrane, and wherein the conductive plate induces an opposing charge in the dielectric membrane.

### Claim 5 (depends on 4)

The disc pump of claim 4, wherein the dielectric membrane comprises silicone rubber.

### Claim 6 (depends on 4)

The disc pump of claim 4, wherein the dielectric membrane comprises polyethylene.

### Claim 7 (depends on 3)

The disc pump of claim 3, wherein the first conductive plate and the second conductive plate are operable to reverse polarity at a frequency (f) in response to receiving the drive signal, and wherein the frequency (f) is equivalent to the resonant frequency of the cavity.