EXHALATION VALVE FOR A PATIENT VENTILATOR

摘要

The exhalation valve (10) includes a valve housing (12) with a valve seat (20) having an annular shoulder (22), and a valve poppet (26) having a face (25) with a corresponding annular groove (24). A soft flexible diaphragm seal (28) disposed between the face (25) of the valve poppet (26) and the valve seat (20) provides a suspended soft seal (28), ensuring perpendicularity in the valve seal (28) for improved accuracy of valve (10) operation. An annular permanent magnet (60) and an annular magnetic ring (62) are disposed around and spaced apart from a magnetic body (36) to define an air gap (64) in which an electromagnetic coil (66) is disposed. The electromagnetic coil (66) is connected to a control mechanism (74) by a flexible circuit connector (73) that is sufficiently slack that provides minimal force transverse to the longitudinal axis of the valve (10). An assembly is provided for adjusting uniformity of the air gap (64) and of concentricity of magnetic body (36) and shaft (32) of the poppet (26), and the control mechanism (74) adjusts the current supplied to the electromagnetic coil (66), compensating for changes in the magnetic field strength of the valve (10) due to changes in temperature, velocity of the valve poppet (26), and patient airway pressure. A flexible diaphragm (44) is also connected between the valve poppet (26) and magnetic body (36) to prevent cross-contamination between the exhalation valve (10) and breathing gas.