Patent ID: 8479733

Claim:
A flow sensor for a medical ventilator system comprising: a valve assembly comprising: a valve seat comprising an attachment aperture, a seat ring, and a pin that extends from the valve seat past the seat ring; and a valve flap attached to the valve seat, the valve flap being composed of an elastomeric material and the valve flap comprising a protrusion configured to be received within the attachment aperture to retain the valve flap to the valve seat; wherein the elastomeric material of the protrusion generates a pre-load that biases the valve flap into engagement with the valve seat such that the valve assembly remains closed in the absence of an externally applied force and the valve flap engages the pin to limit engagement between the valve flap and the seat ring when the valve assembly is closed; a pressure transducer configured to measure a first pressure level at an upstream position relative to the valve assembly, and a second pressure level at a downstream position relative the valve assembly; and a processor connected to the pressure transducer, said processor configured to estimate the flow rate of a fluid passing through a medical ventilator system based on the first and second pressure levels.