MECHANICAL VENTILATION SYSTEM UTILIZING BIAS VALVE

摘要

A portable mechanical ventilator having a Roots blower is configured to provide a desired gas flow and pressure to a patient circuit. The mechanical ventilator includes a flow meter operative to measure gas flow produced by the Roots blower and an exhalation control module configured to operate an exhalation valve connected to the patient circuit. A bias valve connected between the Roots blower and the patient circuit is specifically configured to generate a bias pressure relative to the patient circuit pressure at the exhalation control module. The bias valve is further configured to attenuate pulsating gas flow produced by the Roots blower such that gas flowing to the mass flow meter exhibits a substantially constant pressure characteristic. The bias pressure facilitates closing of the exhalation valve at the start of' inspiration, regulates positive end expiratory pressure during exhalation, and purges sense lines via a pressure transducer module.

主权项

1. An apparatus for attenuating a gas flow from a gas source to a patient circuit, the device comprising a bias valve connected between the gas source and the patient circuit, the bias valve comprising an inlet connected to the gas source, an outlet connected to the patient circuit, a cavity, and a poppet, the poppet configured to reciprocate within the cavity to define a poppet clearance between the poppet and the cavity, and the poppet clearance sized to generate viscous damping of the gas flow when gas passes through the poppet clearance during poppet reciprocation.