Importance

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Abstract

A pneumatic pressure delivery system capable of delivering negative pressure (vacuum or suction) or positive pressure with a precise, continuously variable and predictable control of the pressure delivered is disclosed. The method and apparatus includes the capability of electronically adjusting the variation of pressure to follow any desirable functional mathematical relationship of a control signal. The apparatus includes an electronically controlled pressure regulator in which the pressure at the outlet of a regulator acts upon a piston or diaphragm in opposition to a force produced by an electronic controller. The piston or diaphragm is mechanically coupled to a flow control valve such that the valve alters its position to increase or decrease the flow to its outlet in response to the force exerted on the piston or diaphragm. The invention is also directed toward an aspiration method and apparatus which includes a cassette and a cassette holder to be used in conjunction with the suction and pressure control system. The aspiration method and apparatus utilizes a first chamber having a flexible diaphragm to communicate vacuum to an aspiration port which is connected to a surgical instrument. When the first chamber is nearly filled to capacity, fluid within the first chamber is transferred to a second larger chamber through the application of pressure to the flexible diaphragm. A pair of pinch valves prevents vacuum from being applied to the second chamber and pressure from being applied to the aspiration port.

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First Claim