Abstract: A boiler cleaning device includes a frame mounting a carriage for moving a lance in and out of a boiler along said frame. The carriage is moved by a drive-chain which passes through a differentially geared set of sprockets, one of which carries a pinion rotating a ring gear mounted on a spindle portion of the lance. The spindle has a plurality of recesses each including an abutment and a ramp while the gear carries a spring loaded plunger which engages the abutment to rotate the spindle and the lance in one direction. When the drive is reversed to move the carriage backward, the gear rotates the other direction and the plunger merely rides up the ramps and down the abutments and the spindle does not rotate.

Abstract: A boiler soot blower provides a lance tube having a pair of opposed nozzles at its end. The lance tube is carried by a carriage for reciprocation between an extended and retracted position, and is caused to rotate about its longitudinal axis in timed relationship to the extension and retraction. A lost motion drive is provided for the rotation of the lance tube so that the nozzles produce a helical first spray pattern of cleaning fluid during extension and a second spray pattern of cleaning fluid during retraction which is offset from the first spray pattern and extends substantially midway between the adjacent portions of the first spray pattern. This results in a composite pattern which provides efficient cleaning.