| 摘要 |
<p>A sootblower of the long retracting variety including a drive system which simultaneously rotates the lance tube as it is inserted and withdrawn from the boiler. A variable speed drive is employed to modulate the rotational speed of the lance tube in accordance with the projected distance of the lance tube such that the lance tube is driven faster at intermediate lance tube projected distances thereby optimizing the cycle time of the sootblower. The modulated rotational speed of the lance tube is maintained at all projected distances below the critical speed which varies as a function of projected distance and the sootblower type. By driving the lance tube at certain projected distances at a rotational speed above the critical speed for other projected distances, the translational speed is increased and cycle time reductions are realized as compared with the prior art wherein the lance tube is driven at a constant speed below the minimum critical speed. The lance tube speed may be varied upon retraction and operated at constant speed for insertion or vice-versa or the speed may be varied both on insertion and retraction, as the cleaning requirements of a particular application requires.</p> |
