Abstract: An internal combustion rotary engine that produces mechanical torque is provided. The engine includes an annular planar housing, a rotor, and first and second valves. The planar housing has a substantially circular annulus flanked by first and second cavities and an axial shaft disposed between the cavities. The rotor is disposed on the shaft and rotates within the annulus; The first and second valves are disposed within respective the cavities. Each valve has an arc wedge having outer convex surface and an inner concave surface, a shaft hole between and parallel to the surfaces along a rocking axis, and a pivot shaft that passes through the shaft hole to enable the wedge to rock back and forth within the cavity.

Abstract: A method and apparatus for determining the total flow rate of air flowing through a ventilation installation with a free suction fan (15) is described. The flow rate or a corresponding pressure is determined by measurement of the partial flow rate or a corresponding pressure at at least one measurement point in the vicinity of the inlet opening of the fan. A measurement tube (20) open at both ends is suitably used, and oriented with its longitudinal axis in the inflow direction, flow sensors being arranged inside the measurement tube. In this way, there is obtained good measurement accuracy within a large flow range.