Abstract: A filter for a breathing device is flexible and can be manufactured in a simple manner. The filter includes a flexible frame (5) with a filter port (8) and with an end piece (9). The flexible frame (5) is provided between two filter mats (2, 3). The flexible frame (5) can be folded over along a bent edge (7) such that the filter port (8) and the second end piece (9) are arranged opposite each other.

Abstract: A breathing apparatus includes a filter, a motor and a blower driven by the motor. The filter is disposed ahead of the blower and the blower is configured to generate an air volume flow over the filter. A data storage unit has calibration curves for the air volume flow stored therein and the calibration curves are provided in characteristic line fields referenced to a known ambient pressure (p0, p1). Each of the characteristic line fields has a reference calibration curve referred to a predetermined operating state. A control unit is connected to the motor and the data storage unit. The control unit is configured to extrapolate one of the characteristic line fields for the operation of the motor by comparing a calibration curve ({dot over (V)}ox) for an unknown ambient pressure (px) recorded at a predetermined operating state with a reference calibration curve.

Abstract: A filter for a breathing device is flexible and can be manufactured in a simple manner. The filter includes a flexible frame (5) with a filter port (8) and with an end piece (9). The flexible frame (5) is provided between two filter mats (2, 3). The flexible frame (5) can be folded over along a bent edge (7) such that the filter port (8) and the second end piece (9) are arranged opposite each other.