Pipe Conveyor Operating and Maintenance Procedures
The pipe conveyor comprises numerous components and design features which the Operator and Maintenance crews must be fully aware. Details of the conveyor are dealt with individually below.
NOTE :- It is essential that the conveyor is inspected and monitored before and during operation. It is recommended that the conveyor is visually inspected 2 times per day while in operation and a detailed inspection he performed between the off-loading of each ship.
ATTENTION:- Your attention is drawn to the mandatory requirement for comprehensive training in the operation and maintenance of the conveyor and its components as well as to the need for strict adherence to safety regulations and requirements as specified in the manual and those specified by the Factory, prior to engaging in any activity associated with the operation, maintenance and/or commissioning of this conveyor.
Belt Alignment and Training Procedure.
The alignment of the pipe conveyor belt is important in order to prevent the belt fouling with the structures, chute work. etc. which will result in permanent damage to the belt and the affected structures. In addition, belt alignment is crucial to prevent product being spilled from the pipe conveyor along its length due to the overlap being in the incorrect position. Figure 6.1 indicates the correct alignment of the carrying-side belt.
Incorrect alignment, the 'overlap' has rotated too far, allowing product to leak and cause spillage
Figure 6.1 - Cross-section through the carrying-side pipe form, showing location of 'overlap.
The correct aligmnent / training of the belt must be checked for operation under no-load, partial load and full load conditions. For the initial alignment check i.e. for the initial new belt and for subsequent replacement belts, the conveyor must be started only once all cheeks have been completed as per the Erection Cheek Procedures. The conveyor is then started without load, with suitable monitoring by personnel along the full length of the conveyor.
Once the conveyor is started, the belt overlap must be observed with reference to the rest of the structure. Also the alignment of the belt at the tail and head end must be monitored at start-up and should the 'overlap' move clockwise or anticlockwise in the structure beyon the 20 degrees indicated above, the belt requires training.
Training of the belt should preferably be performed by one individual only. This ensures that the there is no duplication of adjustment to the idlers, especially in this instance considering the length of this conveyor. In addition, training of the betting should commence at the tail-end of the conveyor beginning with the tail pulley, loading section, etc. and progressing along the carrying-strand belt. Once at the head-end, training follows the belt line through the drives, take-up and back to the tail pulley via the return-strand.
To train the belt, each of the pipe conveyors' idler panels are fitted with two training idlers, on the carrying and return strands respectively. These idlers are usually the bottom idlers of each set of six idlers, and are mounted on a bracket which has slotted adjustment holes as depicted in Figure 6.2 above. Where the conveyor negotiates a horizontal curve, the training idlers are usually off-set to the inside of the curve radius.
To adjust the belt training, first establish whether the belt is required to rotate either clockwise or anti-clockwise for the 'overlap' to be at the top (carrying-side) or bottom (return-side) of the idler set. Secondly, establish which idlers on which of the idler panels require adjustment. To do this, the source of the misalignment must be found i.e. where the belt begins to misalign, and these idlers must be adjusted.
The bolts on the identified adjusting idler brackets must then be loosened slightly, to enable the bracket to be turned.
To align the belt, the idler bracket must be turned in the correct direction. Figure 6.3 indicates the effects of turning the training bracket and idler. The effect which this training has on the alignment of the belt is identical to that experienced on conventional conveyors.
Care must be taken to prevent excessive adjustment -of the training idlers. Adjustments must be made in small increments, to three or four adjacent training idlers at one time followed by observation for approximately 5 minutes, to allow the adjustment to take effect before further adjustments are made.
Where idlers are adjusted, the panels should be marked for reference purposes.
Once the belt is running true in the panels, partial load should be conveyed, followed by full load testing. All training idler brackets must be re-tightened once training of the belt is complete.
If it is found that by adjusting a series of training idlers, the belt alignment is not improved, then the adjusted idlers must be re-set to their original positions before proceeding to the next series of panels to make further adjustments. In this way the belt training procedure is conducted in a logical, systematic way.