Abstract: The installation serves to adjust the flow rate of air in a network of ducts such as a mine. It comprises a fan (10) provided with an electric motor (16) powered at a variable frequency. The installation also includes a converter having an adjustable output frequency and measuring means (12, 22) for measuring the flow rate and the total pressure supplied by the fan. It also includes a processor (20), a memory (26) for storing in digital form at least one total-pressure/flow-rate characteristic curve, and optionally a pressure/flow-rate characteristic curve of the fan at at least one predetermined speed; means (30) for displaying said curves; and data input means enabling a reference value (Q.sub.

Abstract: The present invention is a device for removing boulders loosened by an explosion, from the hanging roof of a mining gallery. The device is a pole which supports a pneumatic hammer and a striking head at one end thereof and a gripping handle at its opposite end. The handle has a trigger mechanism for remote control of the pneumatic hammer. The inner section of the striking head is a formation of hollow, honeycombed cells, for reducing the weight of the striking head.

Abstract: A blower has a tubular air flow guiding sleeve. An electric motor is located coaxially within the sleeve in a casing connected to the sleeve by flow-straightening blades and a propeller is fixed to a rotary shaft of the motor and placed in front of the blades. A central unit comprises the tubular casing constituting a single casting with the blades and a part of said sleeve surrounding the propeller. A length of that part around the propeller is machined concentrically to an inner surface of said casing slidably receiving the stator of the motor. A PTFE ring may be located in a recess of the sleeve in radial alignment with the propeller blade tips.