Abstract: The invention relates to a method of manufacturing a heating device (1) which has a fan (3) located behind a grid (2) in an interior (10). The fan (3) is mounted in the interior (10), and the grid (2) is mounted as a part of the heating device (1). The speed of the fan (3) is determined in a contactless manner by evaluating a reflection behavior of the fan (3) in that a light signal (50) is emitted through a recess (20) in the grid (2) in the direction of the fan (3), and/or is received through a recess (20) in the grid (2) from the direction of the fan (3). Furthermore, the invention relates to a heating device (1).

Abstract: Disclosed is a ventilator with an electrical drive and at least one rotating or non-rotating functional unit associated with the drive or with a structural component of the drive for generating and/or influencing an air current, wherein the functional unit is arranged coaxially around the drive or in front of it or after it, and wherein the association takes place directly or indirectly in a positive and non-positive manner by the intermeshing and mutual bracing of connection means.

Abstract: Disclosed is a ventilator with an electrical drive and at least one rotating or non-rotating functional unit associated with the drive or with a structural component of the drive for generating and/or influencing an air current, wherein the functional unit is arranged coaxially around the drive or in front of it or after it, and wherein the association takes place directly or indirectly in a positive and non-positive manner by the intermeshing and mutual bracing of connection means.

Abstract: In a method for pretreating a piezoelectric ceramic (1) and a method for adjusting an injection valve (7), the piezoelectric ceramic (1) is exposed to environmental conditions, leading to a reduction of polarization and also a reduction of the length of the ceramic (1). The obtained length exhibits a greater long-term stability due to said adjusting phase. Consequently, the injection valve (7) can be re-adjusted before use. As a result, renewed adjustment thereof is required only after a long period in service.

Abstract: In a method for pretreating a piezoelectric ceramic (1) and a method for adjusting an injection valve (7), the piezoelectric ceramic (1) is exposed to environmental conditions, leading to a reduction of polarisation and also a reduction of the length of the ceramic (1). The obtained length exhibits a greater long-term stability due to said adjusting phase. Consequently, the injection valve (7) can be re-adjusted before use. As a result, renewed adjustment thereof is required only after a long period in service.