Measurement of a fluid parameter in a pressure support system
First Claim
1. A method of operating a pressure support system having a motor coupled to a blower and a controller operatively coupled to the motor, which is coupled in fluid communication with a patient via a patient circuit, the method comprising the steps of:
- (a) producing a first signal that causes the motor to drive the blower at a set rotational speed to produce a selected pressure for the fluid in the patient circuit;
(b) adjusting a duty cycle of the first signal as the flow of fluid in the patient circuit varies so that the motor drives the blower at the set rotational speed to maintain the selected pressure in the patient circuit; and
(c) calculating a quantitative flow of fluid in the patient circuit based on the adjustments made to the duty cycle of the first signal, wherein the producing, adjusting, and calculating steps are performed by the controller.
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Accused Products
Abstract
A pressure support system has a motor, a switching element that supplies power to motor windings, and a blower coupled to the motor. Rotation of the blower elevates a pressure of fluid in a patient circuit coupled to an outlet of the blower. A rotational speed controller maintains the motor at a set rotational speed corresponding to a selected pressure for the fluid in the patient circuit. The rotational speed of the motor is maintained by a switching signal provided by a rotational speed controller to the switching element to control the actuation of the switching element. A fluid parameter monitoring portion monitors a parameter associated with the flow of fluid in the patient circuit, such as the magnitude, direction, or volume, based on a characteristic, such as duty cycle, of the switching signal, or based on a characteristic of a control signal that is used to generate the switching signal.
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Citations
11 Claims
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1. A method of operating a pressure support system having a motor coupled to a blower and a controller operatively coupled to the motor, which is coupled in fluid communication with a patient via a patient circuit, the method comprising the steps of:
- (a) producing a first signal that causes the motor to drive the blower at a set rotational speed to produce a selected pressure for the fluid in the patient circuit;
(b) adjusting a duty cycle of the first signal as the flow of fluid in the patient circuit varies so that the motor drives the blower at the set rotational speed to maintain the selected pressure in the patient circuit; and
(c) calculating a quantitative flow of fluid in the patient circuit based on the adjustments made to the duty cycle of the first signal, wherein the producing, adjusting, and calculating steps are performed by the controller. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- (a) producing a first signal that causes the motor to drive the blower at a set rotational speed to produce a selected pressure for the fluid in the patient circuit;
Specification