Patent ID: 6029660
Filing Date: 2000-02-29
Classification: A61M

Abstract:
A substance delivery apparatus for use with a system for supplying breathable gas to a human or animal, said system including a pressurized gas flow generator in fluid communication with a mask worn by the human or animal via a flexible conduit, the apparatus including:an airflow sensor adapted to measure the volumetric flow rate of the breathable gas passing through the conduit and generate a first signal indicative of the breathable gas flow rate;a first amplifier to amplify the first input signal into a second input signal also indicative of the breathable gas flow rate;a differentiating filter to derive the first input signal into a third input signal indicative of acceleration or deceleration of the breathable gas and inhalation or exhalation respectively;a linear drive means;a positive displacement diaphragm pump displaced by the linear drive means to deliver the substance to the human or animal during inhalation at a pressure higher than the supplied pressure of the breathable gas;a pressure transducer connected to the conduit, the transducer being adapted to generate a fourth input signal indicative of the pressure of the supplied breathable gas;a second amplifier to amplify the fourth input signal into a fifth input signal also indicative of the breathable gas pressure;a first control system having input means adapted to allow the input of a predetermined sixth input signal indicative of the volume of the substance to be delivered and a predetermined seventh input signal indicative of the amount by which the pressure of the delivered substance is to exceed the pressure of the supplied breathable gas,wherein said first control system is adapted to receive the second, third, fifth, sixth and seventh input signals and calculate and generate a first output signal indicative of the amount of displacement of the linear drive means and a second output signal indicative of the direction of the displacement required to produce a negative or positive pumping pressure.