Abstract: A foldable breathing mask formed with a deep-drawn mask body and sufficiently rigid so as to retain its shape and including at least one fold line for a storage folding of the mask body is a predefined manner.

Abstract: A foldable breathing mask formed with a deep-drawn mask body and sufficiently rigid so as to retain its shape and including at least one fold line for a storage folding of the mask body is a predefined manner.

Abstract: A filter material laid in folds in a plurality of folds, characterized in that the folds are provided with at least one bending portion having a bending resistance moment that is reduced in comparison with the remaining portions and a method and apparatus for producing same.

Abstract: A method and an apparatus for producing a thermoplastic filter material laid in folds, with the folds fixed in close vicinity. The thermoplastic filter material which has been heated for forming the folds is accumulated within a cooling path such that the folds are pushed together and fixed by cooling with respect to their shape.

Abstract: A breathing mask is provided which comprises an exhaling valve disposed in an opening of the breathing mask wall. The exhaling valve includes a thin diaphragm which is adapted to be moved by the breathing pressure during inhaling and exhaling either towards or away from a sealing seat. To provide a less expensive breathing mask whose exhaling valve safely closes in particular in dust-particle-containing air and which nevertheless involves low opening and closing pressures, the diaphragm is provided with an arch. Air is allowed to escape over only a part of the circumference of the diaphragm, while the remaining part of the diaphragm circumference is so connected to a base member that the arching direction of the arch is at least partly reversible by the breathing pressure.