Abstract: A system and a method are described for converting a small motion from a piezoelectric actuator to a larger motion in a valve mechanism. A piezoelectric actuator is connected in series to a mechanical amplifier, and, optionally, a mechanical temperature compensation element and a mechanical fine tuning element, all acting in the same effective direction as the piezoelectric actuator.

Abstract: Methods and devices are described for reducing flow resistance in a flow restrictor during high flows.

Abstract: The disclosure relates to a device for controlling the flow of a fluid through a flow channel. The flow is controlled by means of a flexible conduit with flexible circular segments compressed along the length of the conduit, whereupon the flexible elements collapse against a circular wall.

Abstract: A mechanical amplifier and method for converting a small motion amplitude to a larger motion amplitude are disclosed. The method includes using two or more beams which are connected in series at angles to each other. Undesirable movements arising in the structure are absorbed by the structure through torsion. Each beam is a mechanical motion amplifier, and by connecting these in series, the total amplification is the product of the amplification of the comprised beams. The disclosure also pertains to a device comprising two or more beams connected together at an angle of 90 degrees in one embodiment.

Abstract: The disclosure pertains to a device and a method for compensating for heat expansion effects in solid materials, as well as a method for manufacturing the device.

Abstract: The disclosure relates to a device for controlling a gas flow, e.g., from a breathing system connected to a patient at exhalation. The flow control is conducted by means of a flexible conduit with flexible circular segments being compressed along the length of the conduit, whereupon the flexible elements are collapsed towards a circular wall. The device comprises autoclavable parts and/or disposable parts, which can be separated from the breathing system without exposing staff handling the system to contaminated surfaces in the breathing system when changing patients.

Abstract: The disclosure pertains to a method of charging or discharging a capacitive element, such as a piezoelectric crystal. The disclosure also pertains to a device that implements charging of a capacitive element according to said method. The device comprises a bipolar buck-boost converter, whereby a capacitive element can be charged with both positive and negative voltages. The discharge of the capacitive element is provided with energy recovery and feedback to the device's power supply.

Abstract: A ventilator includes a sensor to monitor a characteristic associated with the delivery of gas to the patient, such as pressure. A sensor power supply (100, 130) is feeding a sensor in the form of a Wheatstone bridge. A first end (104) of the bridge is coupled to a first positive voltage source (112, 142) and a second end (116) is coupled to a second positive voltage source (118, 156, 180). A capacitor (120) is coupled to the second end of the bridge.

Abstract: A ventilator or fluid delivery system that provides a flow of gas to an airway of a user. The ventilator includes a source of gas (30, 32), a conduit (63, 65, 42) that carries the flow of gas to the airway of a patient, a first valve (38, 40) that controls a pressure, flow, or volume, of the flow of gas, a pressure sensor (46) operatively coupled to the conduit between the valve and the patient and adapted to monitor a pressure of the gas in the conduit, and a controller (50) adapted to control the valve based on an output of the pressure sensor The ventilator further includes a restrictor (62) provided in the conduit between the pressure sensor and the patient. The restrictor, in essence, divides the fluid delivery system such that a first volume is defined in the conduit between the valve and the restrictor and a second volume is defined in the conduit between the patient and the restrictor, wherein the first volume is less than the second volume.

Abstract: A directional valve for respiratory devices has a valve body and a valve seat whose contact surface with the valve body is primarily horizontal. In order to enhance and reinforce the directional valve's operation, the valve body contains a ferromagnetic material, preferably permanently magnetized, a coil is magnetically couplable to the valve body, a source of current is connected to the coil, and a control unit controls the source of current in order to regulate current through the coil to magnetically couple the coil to the valve body, in one or both of the closing and opening directions.

Abstract: In a method for analyzing anaesthetic agents and an analyzer operating according to the method, a parameter directly related to the anaesthetic agent's dielectric polarization is determined. A measuring unit has a container for the anaesthetic agent, two capacitor plates, devised so the anaesthetic agent can be interposed between them for analysis, a voltage source, connectable to the capacitor plates for controlled application of at least one voltage across the plates, and a voltmeter, connectable to the capacitor plates for measuring a voltage across the capacitor plates. The measurement results are analyzed in an analysis unit and the anaesthetic agent is identified from the analysis result. Mixing and/or contamination of anaesthetic agents can also be identified.

Abstract: A device for the supply of a gas from a respirator/anaesthesia device to a bedridden patient has at least one gas tube and a connecting interface, which can be connected to the patient, and an adjustable holding device for the gas tube and for the connecting interface. In order to prevent leaks, injury to the patient or damages to the gas tubes when the patient moves or changes position, the device is provided with at least one sensor and the holding device is provided with control arrangement for controlling its movements. The sensor detects movement of the patient is connected via the connecting interface, and a signal generated by the sensor and supplied to the control arrangement which, dependent thereon, controls the holding device such that its movements and therefore the movements of the connecting interface automatically follow the movements of the patient.

Abstract: An ultrasonic nebulizer includes a nebulization chamber for holding a liquid to be nebulized, the liquid being limited by an upper boundary within the chamber, and a nebulization source acoustically couplable to the liquid within the chamber to provide therein an ultrasonic output at an amplitude to cause nebulization. The nebulization source is controllable to vary the amplitude of the ultrasonic output to provide a measurement period during which no nebulization occurs, and a sonar device measures, during the measurement period, a time interval between emission of an acoustic pulse toward the boundary and detection of a component of the emitted acoustic pulse reflected from the boundary, and provides an output signal dependent on the measured time interval for use in determining location information of the boundary within the chamber.

Abstract: A fluid flow meter has a semi-conducting substrate and a number of integral flexible tines orientated across an aperture in the substrate to deflect in the direction of the fluid flow by an amount dependent on that fluid flow. Piezo-resistive regions are included on the respective tines to provide them with electrical characteristics which vary dependent on the degree of deflection. A monitor, operably coupled to the regions of the tines, is provided to monitor the changes in their electrical characteristics and to calculate the flow therefrom.

Abstract: A safety system prevents inadvertent mixing of different anaesthetic agents, during replenishment wherein a new anaesthetic is replenished from a container to an anaesthesia machine containing a flow channel for the delivery of liquid anaesthetic, with a first anaesthetic being present downstream from the flow channel. Inadvertent mixing of different anaesthetics is avoided because the safety system has a measurement unit for identifying the new anaesthetic before the new anaesthetic comes into contact with the first anaesthetic. The measurement unit is arranged upstream from the first anaesthetic.

Abstract: In a method for seeking and setting a resonant frequency for a load impedance and a tuner for carrying out the method, a first frequency sweep is performed over a predetermined frequency interval in order to identify the resonant frequency within the predetermined frequency interval. To maintain the correct resonant frequency, regardless of signal drift and other interference, repeated sweeps are automatically performed within the predetermined frequency interval to identify the resonant frequency repeatedly. Alternating semi-sweeps can be performed to reduce the sweep duration.

Abstract: In a method for supplying fresh gas in manual ventilation of a patient and in a ventilator system for practicing the method, the supply of fresh gas to a breathing bag is regulated. During inspiration, the breathing bag is squeezed, imposing an inspiration on the patient. A detector at the breathing bag senses when the patient exhales, and an identical flow of gas is fed to the system via an inspiratory valve, the flow of fresh gas is directed into the breathing bag and expired gas is prevented from entering the breathing bag. An expiratory valve simultaneously opens to conduct expired gas out of the system.

Abstract: A ventilator to be connected to the airways of a human or an animal includes several functional units, each functional unit being controlled and/or supervised by a separate microprocessor. At least one of the functional units has an analog control unit whereby the microprocessor only compensates for the coarseness in the regulating function of the analog control unit to increase the accuracy. This makes the ventilator efficient, accurate and safe.

Abstract: A device for displaying a parameter value has at least one row of light-emitting diodes in which each light-emitting diode has a position input, and the device has a control circuit with address outputs connected to the position inputs. Faults, such as a short-circuit can be detected more easily by an improved interconnection of the address outputs and position inputs such that two adjacent address outputs are connected to two position inputs physically separated by at least one position input.

Abstract: An apparatus, such as a ventilator, for regulating the flow-through amount of a flowing medium, such as a gas, has a valve with a variable orifice operated by a first regulating circuit with negative feedback. The regulating variable generated by the first regulating circuit controls the size of the orifice so that the difference between a desired value and an actual value for the flow-through amount os minimized, toward zero. To achieve rapid changes in the flow-through amount with a high regulating precision, at least one further regulating circuit is provided to which the regulating variable of the first regulating circuit is supplied as the desired value. The actual value for the further regulating circuit may be the measured position of the closure element for the orifice. The bandwidth and the gain can be optimized for each regulating circuit. The energy consumption can be lowered by current recovery and battery operation can be simplified, in the event of a power outage.