Abstract: The explosion protection device as per the invention is intended to be used for a system located in a closed room whose components are located in a housing. A housing opening is provided in a side wall of the housing that connects to a redirection unit, which effects an upward redirection of a gas stream escaping from the housing opening when an explosion occurs in the housing. The redirection unit has an outlet opening on which a flame-retardant relief device is arranged. The redirection unit is connected to a protective shield that surrounds the outlet opening.

Abstract: A measuring unit for determining the material parameters of a solid material sample of a substance includes a sample holder for accommodating the material sample to be tested, an actuator for generating an excitation vibration, a measuring unit and a measured value analysis unit, the actuator including at least one piezoelectric element to be electrically excited, and the actuator and the sample holder having a common longitudinal axis.

Abstract: An apparatus for purification of air comprising comprises a housing having inlet openings for supplying the air to be cleaned and outlet openings for discharging the cleaned air, a filter system disposed in the housing, and a fan arranged to draw air through the housing and filter system. The filter system includes at least one tubular or bag-shaped fleece filter which is arranged on top of a carrier structure and at least one secondary filter element which has a filter fineness which is smaller than the filter fineness of the fleece filter. The entire apparatus is arranged either stationarily or moveably in regions of greater to lesser dust concentration. The cleaned air is conveyed to the region with the higher local dust concentration and thereby significantly decreases the local dust concentration.