Abstract: A variable inlet vane assembly for use with force draft and induction draft systems having a fan. The vane assembly comprises a mounting base and a hub supported in spaced relationship by a plurality of supports. The inlet vanes are pivotally supported between the base and the hub and are engaged by an actuating ring. An annular sliding bearing is interposed between the actuating ring and the hub. A plurality of stationary dorsal vanes are mounted downstream and in close relationship to the main vanes to control violent back eddies of air which occur at low vane closures.

Abstract: Control apparatus and method for reducing oil-well pounding and preventing subsequent damage to a producing oil well and an oil-well pump assembly, while maintaining optimum oil-well productivity is disclosed. The control apparatus includes vibration-sensor means operatively coupled to an oil-well pump assembly to detect shock pulses generated by the down-hole pump assembly of the oil well, and including means for transmitting the sensed pulses as equivalent electrical signals to a control means for determining the magnitude and frequency of the vibrations or shock pulses received from the sensor means.