Abstract: An improved system for delivering oxygen on demand to a user comprises a pressure transducer for sensing pressures during the breathing cycle of a user and for creating an electrical signal proportional to said sensed pressures, an electronic amplifier for amplifying the signal to at least 10,000 times the original signal strength, electronic filters for regulating the amplitude of the signal and for correcting the point of the signal where expiration stops and inspiration begins to correspond to zero respiratory pressure, an on/off switching circuit and cooperating valve drive circuit for switching to an on condition in response to a preselected first pressure and to an off condition in response to a preselected second pressure, and a valve driven by the valve drive circuit means for directing oxygen from an oxygen source to a user.

Abstract: An improved apparatus for monitoring a respiratory circuit comprises two independent pressure sensing means, a first pressure sensing component having a preset minimum pressure for creating an alarm condition in response to pressure falling below the minimum, and a second pressure sensing component having an adjustable low pressure threshold setting means and for creating an alarm condition if the patient's breathing cycle pressure fails to periodically pass through the low threshold pressure. A preferred embodiment includes visual pressure indicating means including a display of the low threshold pressure setting and a display of the patient's breathing cycle pressures.

Abstract: The present invention is an improved method and apparatus for monitoring a battery supply by comparing the monitored battery voltage against average discharge information for the battery supply recommended for the apparatus, estimating battery life after receiving a prompt to do so and, automatically and periodically prompting the estimated battery life calculation.

Abstract: An improved ventilator monitor and alarm apparatus includes circuit means for actuating the apparatus in response to sensed pressure in a ventilator circuit.

Abstract: The present invention is an improved method and apparatus for condition sensing and displaying a numeric value associated with the sensed condition wherein the improvement comprises (1) circuitry calibrating the display of the numerical value associated with the sensed condition to a numerical value associated with the sensed condition in a normal ambient environment, while the sensor is within the normal ambient environment; and (2) circuitry for calibrating the display of the numerical value of the sensed condition to a numerical value associated with the sensed condition in a known offset environment which is different than the normal ambient environment, while the sensor is in the known offset environment.

Abstract: An oxygen concentrator having one or more molecular sieve beds for selectively adsorbing nitrogen from atmospheric air for increasing the oxygen concentration of a product gas, a reservoir for receiving the product gas, a surge tank, a compressor for charging atmospheric air to the sieve beds and surge tank and a valve and valve switching means for directing atmospheric air from the compressor to the sieve beds and surge tank includes means for sensing the withdrawal rate of product gas from the reservoir and a microprocessor having means for switching the valve for charging the surge tank for a miniumum time required to achieve a product gas having a selected oxygen concentration at the sensed rate of withdrawal.

Abstract: An improved oxygen concentrator assembly includes a microprocessor and cooperating means for monitoring or sensing functions and performance of various components of the concentrator. A test apparatus having means for selecting any of the functions monitored by the microprocessor is connected to the concentrator and displays the selected monitored functions for diagnosing performance levels and component problems or failures.

Abstract: An oxygen concentrator having molecular sieve beds for selectively adsorbing nitrogen from atmospheric air for increasing the oxygen concentration of a product gas, a reservoir for receiving the product gas, a compressor for charging atmospheric air to the sieve beds and a valve and valve switching means for directing atmospheric air from the compressor to alternate sieve beds includes means for sensing the withdrawal rate of product gas from the reservoir and a microprocessor provided with the minimum time required for charging the respective sieve beds to achieve a product gas having a selected oxygen concentration at the sensed rate of withdrawal and means for switching the valve to charge the beds for the minimum charge time.

Abstract: An improved oxygen concentrator includes an oxygen sensor, valve and timer for periodically directing a breathable gaseous mixture having increased oxygen concentration to the sensor. A preferred assembly includes an alarm and means for increasing oxygen concentration in the breathable gaseous mixture when the concentration falls below a selected concentration.

Abstract: A condition monitoring system such as a hospital oxygen monitoring and analyzing device which is battery powered and of such low current drain circuitry that the monitor may be maintained ON continuously. The circuitry senses battery condition when the end of battery life is approaching as indicated by terminal voltage drop. The circuitry continues to provide an accurate display but also indicates a part of the display and additional symbol. The circuitry provides a separate indication under calibration conditions, and the improved voltage regulator includes a transistor back biased to breakdown as the regulation device. A remote sensor is used and engaging the sensor with the unit, automatically powers all circuitry.

Abstract: A device for exercising the lungs by forced inhaling or exhaling comprises a mouthpiece and a valve assembly incorporating a valve housing unit having a gas inlet port and a gas outlet port both communicating with a cavity in which a movable valve body is received and which valve body has a first passageway for directing gas between the inlet and outlet ports and a second passageway for directing gas between a by-pass port and the gas outlet port. The relative amount of gas passing through the gas inlet port and through the gas by-pass port is determined by the position of the valve body and can be regulated by moving the valve body. The device also includes means for monitoring the flow of gas passing through the gas inlet port and preferably the length of time of that gas passage, and means for counting sequential inspirations or expirations of the user during the exercise.