Patent ID: 8752579

Claim:
A vacuum backflow prevention system, comprising: a fluid ejector tube adapted for insertion into a patient's mouth; a backflow prevention device, comprising: a distal portion defining a valve seat portion and an inlet, the distal portion configured for operative connection to the fluid ejector tube; a proximal portion defining an outlet and a valve contact surface, the proximal portion configured for operative connection to a vacuum source and to the distal portion; a valve member being captured between the valve contact surface of the proximal portion and the valve seat of the distal portion at a first end along a portion of a peripheral edge of the valve member, the valve member being moveable from a first position substantially blocking fluid flow between the inlet and the outlet, and a second position wherein a second end of the valve member opposite the first end is moved in a direction toward the outlet to permit fluid to flow from the inlet to the outlet under a vacuum condition applied by the vacuum source at the outlet, the valve member being configured to bend at a location radially inward from the peripheral edge and at a location spaced closer to the first end than the second end; and a valve protrusion positioned on a proximal side of the valve member in contact with the proximal portion of the backflow prevention device, the valve protrusion being configured to bias the valve member into the first position.