The role of fixing bolts in a screw conveyor

The stuffing box at both ends of the spiral shaft of the pulse bag type dust collector in the conveyor is sealed by packing packing, the packing elasticity is limited, and the screw shaft is made of φ57×5mm seamless steel pipe welded single-headed spiral, although there is a hanging bearing device in the middle. Supporting the screw shaft, but the deflection of the screw shaft is still too large, the wear of the screw shaft and the packing is accelerated, the gap between the screw shaft (optical shaft section) and the packing is increased, and air leakage and powder leakage occur under positive pressure working conditions.

The screw conveyor thrust bearing device and the flat bearing device are respectively moved to the outside of the ends of the head and the tail of the machine body, and are separated from the conveyor body.

Double row radial spherical ball bearings, which can withstand radial and axial loads, and have self-aligning function. In the bearing housing, the bearing outer ring can have a sliding distance of 12mm in the axial direction for the screw shaft to freely expand and contract, and the actual working clearance of the screw shaft after thermal expansion is 2~3mm.

The suspended bearing device of the screw conveyor is connected to the short shaft φ80mm, and is directly inserted into the hollow core screw shaft. They are respectively fixed by two spaced bolts. The fixing bolts simultaneously serve the fixed transmission torque and the safety pin.

The outer side of the body is still sealed with a stuffing box, and a set of labyrinth seals is added to the inside of the body. In order to improve the sealing effect, the length of the labyrinth seal is designed to be 110mm. Considering the thermal expansion and contraction of the screw shaft and the body, the axial original gap is 12mm for the powder conveying screw conveyor and 6mm for the spiral bag conveyor of the pulse bag type dust collector. The actual working clearance of the screw shaft after thermal expansion is ≥3mm.

After the transformation, the conveyor runs smoothly, and the bearing device does not have any roller jam and journal wear accidents. The connecting short shaft of the suspension bearing device and the screw shaft are occasionally broken, but the screw shaft is effectively protected.

In order to facilitate the replacement of the fixing bolts, the cover plate of the powder conveying screw conveyor is partially made into a quick opening door type cover at the corresponding place. When the fixing bolts are replaced, the conveyor inlet is filled with phosphate rock powder after the fixing screw is broken, which acts as a self-sealing function. As long as the inlet valve of the small main exhaust fan is closed, the screw conveyor of the pulse bag type dust collector is stopped. The system can be replaced within 10 to 15 minutes without stopping the system.