Patent ID: 7865996
Filing Date: 2011-01-11
Classification: B08B,F22B,F23J,F28G

Abstract:
1. A retracting rotary sootblower for blowing a fluid cleaning medium against internal surfaces of a combustion device, comprising: a screw tube assembly which can be extended into and retracted from the combustion device and slidably overfitting a feed tube, the screw tube assembly having a nozzle extension and a screw tube having helical grooves; a nozzle at an end of the nozzle extension for discharging the cleaning medium; a cleaning medium valve having a valve trigger for controlling the flow of the cleaning medium between on and off positions; a frame for supporting the screw tube assembly, the feed tube, and the valve; a hub mounted to the frame and driven to rotate and having pin means for engaging the helical grooves; a motor drive for rotating the hub; a guide bar mounted to the frame; a cam plate mounted to an end of the screw tube assembly and having a plurality of peripheral notches for engaging the guide bar, and one or more segments engaging with the valve trigger to actuate the valve trigger to control the valve between the on and off positions; and an electric controller for operating the motor drive to rotate the hub causing the screw tube assembly to be extended through the interaction between the helical grooves and the pin means with a first of the cam plate peripheral notches engaging the guide bar, and upon extension of the screw tube assembly, the first of the cam plate notches escapes from the guide bar and continued rotation of the motor drive causes rotation of the screw tube assembly and the cam plate, and the motor drive reversing rotation and the screw tube assembly and the cam plate stopping at a position of engagement between a second of the notches and the guide bar, whereby the cam plate and the screw tube assembly are indexed to different indexed positions between successive operating cycles.