Abstract: A method and apparatus for treating a breathing disorder and, more particularly, a method and apparatus for providing a pressurized air flow to an airway of a patient to treat congestive heart failure in combination with Cheyne-Stokes respiration and/or sleep apnea or other breathing disorders. A positive airway pressure ventilator is utilized in combination with an algorithm that adjusts IPAP and EPAP in order to counter a Cheyne-Stokes breathing pattern. Cheyne-Stokes respiration is detected by monitoring a peak flow of the patient.

Abstract: A pressure support system and method in which a gas flow generating system provides a continuous flow of breathing gas at selectable pressure levels. A patient circuit and interface communicate the continuous flow of breathing gas to the airway of a patient. A controller causes the gas flow generating system to provide the continuous flow of breathing gas to the patient at a first pressure level P1 in an initial therapy session. Thereafter, the pressure level of the continuous flow of breathing gas is increased from the first pressure level P1 to a final pressure level P2 over a first predetermined number D of days. More specifically, in one embodiment, the pressure level is incrementally increased by a predetermined incremental amount &Dgr;p after n therapy sessions taking place on separate days over this first predetermined number D of days.

Abstract: A system and method for providing a pressure support therapy administered to a patient, where at least one parameter associated with the pressure support therapy is varied according to a time-base parameter variation function. More specifically, at least one parameter or at least one group of parameters associated with a pressure control relation for providing a proportional assist ventilation (PAV) or a proportional positive airway pressure (PPAP) mode of ventilation is varied according to a time-based parameter variation function to control the PAV or PPAP ventilation with a maximum degree of flexibility.

Abstract: A valving arrangement for use with or for a blower-based ventilator system, such as a pressure support ventilator, and a pressure support ventilator having such a valving arrangement, in which blower output can be controlled in such a manner that desired levels of pressure are able to be provided without excessive waste of blower output flow. In one preferred embodiment, a first valve is provided that serves to restrict blower flow, without venting the same from the system, along with a second valve for relieving pressure as needed. Also contemplated herein are methods for controlling such a valving arrangement.

Abstract: A high-volume source for very low frequency applications in which conventional speakers are inadequate is disclosed. A presently preferred embodiment comprises a reservoir 32 with a pressure relief 33; a controller 34; a supply blower 36; an exhaust blower 38; a positive plenum 40; a negative plenum 42; an orifice plate with valving 44; a horn 46; and pressure transducers 48, 50, 52, 54, feeding detected pressure levels to the controller 34. An electrical command signal s(t) is also input to the controller. The command signal is a voltage analogous to the acoustic pressure or volume velocity to be output by the source.

Abstract: An adaptive noise control system comprises a reference microphone (12) (FIG. 2) for generating a reference signal (x(t)) that is correlated with noise emanating from a primary noise source (10), secondary loud speaker sources (S.sub.1, S.sub.2, . . . S.sub.N) for generating a plurality of secondary sound waves, microphones (e.sub.1, e.sub.2, . . . e.sub.M) for detecting a plurality of far-field sound waves in a far-field of the primary noise source and generating a plurality of error signals (e.sub.1 (t), e.sub.2 (t), . . . e.sub.M (t)) each of which is indicative of the power of a corresponding far-field sound wave, and an adaptive controller (14) for controlling the secondary sources in accordance with the reference signal and the error signals so as to minimize the power in the far-field sound waves.

Abstract: Vibration of a system such as a motor and pump on a platform or a transformer is minimized by applying a compensating force to the system. The optimum compensating force is determined by measuring the initial vibration and using that measurement in one of three algorithms to determine an adjustment to be made to the compensating force applied to the system at the time the initial vibration was measured. The adjusted compensating force is applied to the system which changes the vibration. That vibration is measured and applied to the selected algorithm to determine a second adjustment to the compensating force. The process is repeated until a compensating force is found which produces zero vibration, minimum vibration or a desired vibration. A plurality of sensors for measuring vibration and a plurality of actuators for applying a compensating force are preferably used.

Abstract: A system and method are provided for monitoring synchronous blade vibration in a turbo-machine. At least three sensors capable of detecting the arrival of each blade are arranged about the cylinder which surrounds the tips of the blades. The location of the sensors is selected to minimize the influence of errors in the data. To this end, and to simplify the installation of the sensors into the cylinder, the sensors may be non-uniformly spaced. The location of each sensor for purposes of constructing Fourier transforms is determined using the arrival times at the blades at each sensor, expressed as a fraction of a rotor revolution. The transform matrix is constructed for a predetermined discrete set of M harmonics, so that M harmonics are analyzed simultaneously, the number of harmonics which can be simultaneously analyzed is related to the number of sensors used.

Abstract: A processor provides N series of discrete values, with each series of discrete values approximating a sinusoidal signal and N being the number of sensors with which a BVM to be tested is normally used. N digital to analog converters are provided, each receiving one of the N series of discrete values and producing an analog signal therefrom. The analog signals have zero crossings incorporating known turbine blade vibration information. N filters are provided, with each filter being responsive to one of the converters for filtering the analog signals. Circuitry is provided for producing an output pulse simulating a once per revolution pulse. Clock circuitry is provided for producing clock pulses which are input to the N converters and the circuitry for producing the output pulse for synchronizing the operation of the converters with the operation of the circuitry producing the output pulse.

Abstract: An active acoustic attenuation system for attenuating tonal blade pass noise in a multi-bladed fan uses a sinusoidal rotational speed signal produced by an accelerometer mounted on the fan as the reference signal for a filtered-X LMS (least mean squarae) adaptive filter controlling a canceling sound generating speaker. The sinusoidal signal is clipped by a zero crossing detector to produce a rectangular wave signal having harmonics which include the fundamental and harmonics of the tonal noise to be eliminated. When the system is used with axial flow fans having a central hub, the speaker is mounted facing the fan and coaxial with the hub. When the fan has a straight discharge conduit, the speaker is no larger in diameter than the fan hub to preclude restricting flow; however, there is no restriction on the size of a speaker facing the fan when it is mounted in the rear wall of a discharge chamber having a lateral discharge opening.