US 4,803,959 A · Indexing sootblower

Abstract

A long retracting sootblower for boiler cleaning of the type having a lance tube which is advanced into and out of a boiler and simultaneously rotated, and having one or more nozzles discharging a jet of blowing medium which trace helical paths. An indexing mechanism is provided to change the positioning of the helical paths traced by the nozzles between successive actuation cycles to minimize boiler erosion and mechanical stress caused by repeated blowing medium impact against surfaces within the boiler. the indexing mechanism includes relatively slidable longitudinal advancement rack sections which cause the engaging pinion gears to index by one or more teeth upon each actuation cycle. A movable rack portion is biased by a compliant element to remain in a normal position until initial advancement of the lance carriage which causes the movable portion to be indexed with respect to the fixed portion of the rack. The movable rack portion returns to its normal position during other periods of the actuation cycle thereby providing said indexing.

Claims11

Dependent claims

A sootblower having a lance tube with one or more nozzles for projecting a stream of blowing medium against surfaces within a boiler, said lance tube being periodically advanced into and out of the boiler and simultaneously rotated such that the stream of blowing medium projecting from the nozzle traces a helical path, said sootblower comprising;

drive train means for driving said lance tube to undergo said longitudinal and rotational motions in a synchronized manner thereby causing said nozzles to trace said helical path, and
indexing means for displacing the position of said helical path from one sootblower actuation cycle to another such that the helical paths traced by said nozzle are longitudinally offset between said actuation cycles.

A sootblower having a lance tube with one of more nozzles for projecting a stream of blowing medium against surfaces within a boiler, said lance tube being periodically advanced into and out of the boiler and simultaneously rotated such that the stream of blowing medium projecting from the nozzle traces a helical path, said sootblower comprising;

a frame,
at least one longitudinally extending toothed rack assembly affixed to said frame,
a carriage for traveling along said frame and coupled to said lance tube for controlling the longitudinal and rotational motion of said lance tube, said carriage including drive train means driven by a motor for rotating said lance tube and moving said carriage longitudinally through one or more pinion gears engagable with said toothed rack assembly, said drive train establishing a synchronized relationship between said longitudinal and said rotational motions of said lance tube thereby causing said nozzle to trace said helical path, and
said rack assembly including interengaging fixed and movable portions, said movable portion being longitudinally movable between a first and second position, and biasing means urging said movable portion toward said first position, whereby during a portion of the operating cycle of said sootblower, said pinion gear engages said movable portion moving it to said second position against said biasing means and thereafter moves out of engagement with said movable portion allowing said movable portion to return to said first position under the influence of said biasing means, whereby said pinion gear is indexed with respect to said rack assembly upon each actuation cycle of said sootblower causing said helical path to be displaced between successive actuation cycles of said sootblower.

1 more element

Dependencies are inferred from the claim text.

Indexing sootblower

Life of this patent

Indexing sootblower

Life of this patent

Abstract

Claims11