Abstract: In a method and arrangement for evaluating effective flow resistance of a patient breathing circuit connected to a mechanical breathing assist device, a flow controller is operable to temporarily introduce an occlusion to the gas flow within the breathing circuit at a time after the end of an inspiration phase of a breathing cycle provided by the breathing assist device. A sensor unit 34 has a flow sensor for measuring gas flow within the circuit and a pressure sensor for measuring gas pressures within the circuit. An evaluating unit receives measurements from the sensor unit, to determine for a measured gas flow a value of a pressure drop within the breathing circuit after the introduction of the occlusion, and establishes a relationship between the calculated pressure drop and the measured gas flow, such as based on the known Blasius formula.

Abstract: A valve for regulating a gas flow has a valve seat and a valve body, movable against the valve seat. The valve achieves high accuracy, a wide dynamic range and high operating reliability by causing the valve body substantially only to move axially against the valve seat and by using a stepper motor to actuate the valve body's axial movement against the valve seat with a non-linearly threaded engagement between the stepper motor and valve body so that the valve body performs continuous, non-linear, axial movement against the valve seat.

Abstract: in a method and arrangement for evaluating effective flow resistance of a patient breathing circuit connected to a mechanical breathing assist device, a flow controller is operable to temporarily introduce an occlusion to the gas flow within the breathing circuit at a time after the end of an inspiration phase of a breathing cycle provided by the breathing assist device. A sensor unit 34 has a flow sensor for measuring gas flow within the circuit and a pressure sensor for measuring gas pressures within the circuit. An evaluating unit receives measurements from the sensor unit, to determine for a measured gas flow a value of a pressure drop within the breathing circuit after the introduction of the occlusion, and establishes a relationship between the calculated pressure drop and the measured gas flow, such as based on the known Blasius formula.

Abstract: A valve for regulating a flow of gas, has a valve body with an inlet for the gas to be regulated, an outlet for a regulated flow of a gas, a valve seat with a valve opening, a moving closure part having a tensioned membrane mounted inside the valve body and a plunger, which is movable by a plunger actuator, whose end acts on the membrane, causing the closure part to close and open the valve opening and regulate the flow of gas through same. The flow of gas can be simply and inexpensively regulated, with great accuracy and repeatability and which forms a hermetic seal when the valve is in the closed position, a rigid, flat plate is be arranged opposite the valve seat the plate having a surface area which is at least equal to the surface area of the valve seat.

Abstract: A valve for regulating a gas flow has a valve housing with an inlet for the gas to be regulated, an outlet for a regulated gas flow, a valve seat with a valve opening, and a movable sealing part with a controllable shaft, the terminal side of the sealing part making and breaking a seal between the valve seat and the sealing part such that the sealing part closes and opens the valve opening and regulates the gas flow through the valve opening. In order to allow particularly small gas flows to be repeatedly regulated with high precision and a large dynamic, the plane of the terminal side of the sealing part and the plane of the valve seat form a non-zero angle, allowing the terminal side of the sealing part to press against the valve seat, or to detach therefrom, so that the terminal side gradually closes and opens the valve opening.