Life Products, Inc.

James A Hoerlein

Wayne R Apple

G Kenneth Russell

A lung ventilator is provided that reduces the number of mechanical components and is able to rapidly adjust to provide a selected volume of air or other gas for delivery to a patient's lungs. The ventilator includes a brushless-type DC electric motor having a number of coils that are energized in a predetermined manner to cause reciprocating movement of a piston within a cylinder. The retracted end position of the piston in a cylinder is used to define the volume of air that is to be received by the patient. Three Hall sensors are connected to the motor at predetermined locations and sense the position of the rotor as it rotates due to the energization of the coils. Each of the pulsed outputs from the Hall sensors is out-of-phase relative to the other Hall sensor outputs. The six different binary outputs of the Hall sensors are identified so that a ROM is able to provide a predetermined output for each of the identified Hall sensor combinations inputted to the ROM. The outputs from the ROM are applied to driving transistors, the outputs of which are applied to the motor coils to cause desired rotational movements of the motor rotor. The position of the piston is monitored also using the Hall sensor outputs. The actual position of the piston is found and compared with the desired or selected position of the piston, which is based on a selected volume of gas to be sent to the patient. When the actual position of the piston corresponds to the selected position, piston movement is stopped. A reference sensor is used in determining a reference piston position from which the actual piston position can be found at any instance in time. The present invention also includes a one-piece manifold to which the cylinder is mounted. The manifold includes a number of passageways along which air is carried to the patient.

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Boulder, CO, United States of America

James A Hoerlein