Varying helical sootblower

Abstract

A sootblower to project a blowing medium into a boiler and a method of cleaning a boiler using a sootblower are disclosed. The sootblower includes a hub disposed within a housing, in which ends of the hub are configured to receive a lance and the blowing medium. A drive shaft of the sootblower is then configured to rotate the lance with respect to the boiler in a rotational direction at a first ratio relative to the drive shaft when the drive shaft is rotated in a first direction, and is configured to rotate the lance with respect to the boiler in the rotational direction at a second ratio relative to the drive shaft when the drive shaft is rotated in a second direction.

1 . A sootblower to project a blowing medium into a boiler, the sootblower comprising:
 a drive shaft configured to axially insert a lance into a boiler when rotated in a first direction and axially remove the lance from the boiler when rotated in a second direction;   the drive shaft configured to engage a first rotational mechanism when rotated in the first direction, wherein the first rotational mechanism is configured to rotate the lance with respect to the boiler in a rotational direction at a first ratio relative to the drive shaft; and   the drive shaft configured to engage a second rotational mechanism when rotated in the second direction, wherein the second rotational mechanism is configured to rotate the lance with respect to the boiler in the rotational direction at a second ratio relative to the drive shaft.   
   
   
       2 . The sootblower of  claim 1 , further comprising a hub connecting the lance to a feed line supplying the blowing medium to the sootblower. 
   
   
       3 . The sootblower of  claim 2 , further comprising a housing to contain the drive shaft, the hub, and the first and second rotational mechanisms. 
   
   
       4 . The sootblower of  claim 3 , further comprising a lubricant disposed within the housing. 
   
   
       5 . The sootblower of  claim 2 , wherein the hub comprises an inner wall and an outer wall with a gap disposed therebetween, wherein the outer wall comprises vents. 
   
   
       6 . The sootblower of  claim 1 , further comprising pinion gears attached to the drive shaft and configured to engage a rack to provide translational motion for the sootblower. 
   
   
       7 . The sootblower of  claim 1 , wherein the blowing medium is steam. 
   
   
       8 . The sootblower of  claim 1 , wherein the lance comprises a venturi nozzle. 
   
   
       9 . The sootblower of  claim 1 , further comprising a worm gear attached to the drive shaft, wherein a motor is configured to bidirectionally rotate a worm engaging the worm gear such that the worm rotates the drive shaft. 
   
   
       10 . The sootblower of  claim 1 , wherein the first rotational mechanism and the second rotational mechanism comprise one-way rotational mechanisms. 
   
   
       11 . A sootblower used to project a blowing medium, comprising
 a hub disposed within a housing, wherein a first end of the hub is configured to receive a lance and a second end of the hub is configured to receive the blowing medium; and   a drive assembly configured to convert bidirectional rotational motion from a drive shaft into unidirectional rotational motion for a hub, wherein a ratio of a first direction of the bidirectional rotational motion to the unidirectional rotational motion varies from a ratio of a second direction of the bidirectional rotational motion to the unidirectional rotational motion.   
   
   
       12 . The sootblower of  claim 11 , wherein the drive assembly comprises:
 a first one-way rotational mechanism and a second one-way rotational mechanism attached to the drive shaft; and   a first gear train and a second gear train engaged with the first one-way rotational mechanism and the second one-way rotational mechanism, respectively;   wherein the each of the first gear train and the second gear train is configured to engage the hub.   
   
   
       13 . The sootblower of  claim 12 , wherein the drive shaft, the first and second one-way rotational mechanisms, and the first and second gear trains are disposed within the housing. 
   
   
       14 . The sootblower of  claim 13 , further comprising a lubricant disposed within the housing. 
   
   
       15 . The sootblower of  claim 14 , wherein the lubricant comprises synthetic oil. 
   
   
       16 . The sootblower of  claim 11 , further comprising a worm gear attached to the drive shaft, wherein a motor is configured to provide bidirectional rotational motion to a worm engaging the worm gear, thereby providing bidirectional rotational motion for the drive shaft. 
   
   
       17 . The sootblower of  claim 16 , further comprising rollers rotatably attached to the housing and configured to travel along tracks. 
   
   
       18 . The sootblower of  claim 17 , further comprising an intermediate support attached to one of the tracks to support the lance and electrical cords distributed outside and along the other of the tracks. 
   
   
       19 . A method for cleaning a boiler using a sootblower in accordance with  claim 1 .