In order to increase the operational safety of an actuator (1) including an electric motor (2) and a transmission, preferably a non-self-locking transmission (3), a braking device is provided which allows the controlled, self-actuating displacement, by a retarding brake (5), of an actuating element connected to the actuator (1) via the transmission (3). The actuating element can be held in a fixed position by an additional holding device (6), even if the electric motor (2) fails. The actuator can be used to drive heavy sluice gates, in the event of a power failure, in a controlled free-fall operation at a constant rate of fall, or to hold them in a defined position. The holding device and the retarding brake can be combined in a common housing (11) to form a braking module (12) which can be designed to be used modularly with existing motor actuators and transmissions.

An explosion proof actuator assembly and servo system is described. Embodiments of the present invention include an explosion proof actuator assembly and servo system that may implement a rotating nut and a threaded member to effectuate an opening and closing of a valve.

An explosion proof actuator assembly and servo system is described. Embodiments of the present invention include an explosion proof actuator assembly and servo system that may implement a rotating nut and a threaded member to effectuate an opening and closing of a valve.

A housing that can be provided on the inside with a lining, made of an open-pore material and preferably covering at least two sides of the housing, for the reduction of internal explosion pressure. In addition,. or alternatively, a molded body made of the open-pore material, in particular a bonded fiber material, can be arranged in the housing. Methods are used to provide an assembly of an open-pore material and a flameproof body in order to create an assembly that has a higher temperature class and/or a higher flameproofing class than those for which the flameproof body is designed.

An explosion-proof electrical machine and, more specifically, to an electrical machine comprising an internal pressure reduction device. The internal pressure reduction device comprises a base for installation in a region of the casing below the connection box, a base being configured to receive a plurality of volume filling pieces; wherein the base comprises a bottom part and a part of wall which is extended by at least a part of the periphery of the bottom part. The base may further comprise at least one engaging means for each piece of the plurality of volume filling pieces.

An explosion-proof electrical machine and, more specifically, to an electrical machine comprising an internal pressure reduction device. The internal pressure reduction device comprises a base for installation in a region of the casing below the connection box, a base being configured to receive a plurality of volume filling pieces; wherein the base comprises a bottom part and a part of wall which is extended by at least a part of the periphery of the bottom part. The base may further comprise at least one engaging means for each piece of the plurality of volume filling pieces.

A housing (100) for a box fan (1), the box fan (1) and an assembly method therefor are provided. The box fan (1) includes a housing (100) and a fan blade. The housing (100) includes two shields (111, 112) and a frame. The two shields (111, 112) are arranged opposite to and spaced apart from each other. The frame is arranged between the two shields (111, 112). The frame and the two shields (111, 112) are joined and mounted through their own structures respectively, and at least one of the shields can be attached to or detached from the frame by pushing or pulling. The fan blade is rotatably installed in the housing (100). The box fan is easy to assemble and low in cost.

A housing (100) for a box fan (1), the box fan (1) and an assembly method therefor are provided. The box fan (1) includes a housing (100) and a fan blade. The housing (100) includes two shields (111, 112) and a frame. The two shields (111, 112) are arranged opposite to and spaced apart from each other. The frame is arranged between the two shields (111, 112). The frame and the two shields (111, 112) are joined and mounted through their own structures respectively, and at least one of the shields can be attached to or detached from the frame by pushing or pulling. The fan blade is rotatably installed in the housing (100). The box fan is easy to assemble and low in cost.

An electric machine includes a conductive element disposed in such a way as to connect a first track and a second track of an electric power circuit to close the circuit; the conductive element being held in position by at least one mechanically breakable joint which, if subjected to a predetermined force, mechanically yields or breaks and thereby opens the electric power circuit; the machine includes a system for releasing the conductive element from the first and/or the second track if the casing of the electric machine is moved near the cap which covers the machine.

An electric machine includes a conductive element disposed in such a way as to connect a first track and a second track of an electric power circuit to close the circuit; the conductive element being held in position by at least one mechanically breakable joint which, if subjected to a predetermined force, mechanically yields or breaks and thereby opens the electric power circuit; the machine includes a system for releasing the conductive element from the first and/or the second track if the casing of the electric machine is moved near the cap which covers the machine.