Blockage of Screw Conveyors

Blockage of Screw Conveyors

Blocking problem is the most common fault of screw conveyor which will affect the normal production. So how to address the blockage problem? This article will analysis this kind of problem and give some useful advice.

Since screw conveyor conveying space is small and it is sensitive to material, intertwining phenomenon is easy to occur when screw shaft rotates, blockage occurs in the place of hanging bearing. So blocking problem is the most common fault of screw conveyor which will affect production and increase power consumption, even the motor will burn out and screw shaft twist off which will affect the normal production. Blocking problem is caused by many reasons, we can take measures to avoid this problems:

1. Select reasonable screw conveyor technical parameters, for example, if using low speed screw conveyor the rotating speed can not be too fast.

2. Carry out the operation procedures strictly, non-load start-up and stop to ensure continuous evenly material feeding. 

3. Increase the outlet or extend the chute end dimension to solve the problem of unsmooth discharging or can not discharge material timely .At the same time, you can also install a section of reversed screw blade to avoid blocking. 

4. Clean up the material inside the screw conveyor in order to prevent big impurity or fibrous material enter into the screw conveyor and occurs blocking.

 

5. Reduce the transverse dimensions of intermediate bearing as much as possible in order to reduce the possibility of material passing through the intermediate bearing.

6. Install a level sensor and blockage sensor which can achieve the purpose of automatic control and alarm. 

The Reasons Why Screw shaft of Screw Conveyors Stops Rotating

The Reasons Why Screw shaft of Screw Conveyors Stops Rotating

Generally, if screw shaft of screw conveyors stops rotating, it mainly caused by the following three reasons:

 

1. The size of conveying material is too big and can't pass through the intermediate bearing, material resistance here is too big which will lead to motor overload and stop operation. Then you must clean up the material inside the screw conveyors .

2. The place of intermediate bearing resistance is large, sealing damages. Material will go into the bearing which will lead to bearing stops rotation or bearing damages.

 

3. Bearing of gear motor burns out.

If the reducer bearing temperature rises too fast after start-up and along with abnormal noise and reducer vibration, at this time, you should stop the machine quickly and the reason may be caused by the following aspects:

1) If the reducer output shaft bearing temperature is high ,but input shaft bearing temperature is normal. This is because the screw shaft centerline offsets or reducer output shaft bearing damages, or head and tail bearing loosens. Here you need to loosen the coupling between reducer output shaft screw shaft, correct and install.

2) If the bearing temperature of reducer output shaft is normal, but input shaft temperature is high. This is because the motor fixed components loosen or reducer output shaft bearing damages, you need to loosen the coupling between reducer input shaft and the motor, correct and install.

3) If both of reducer output and input bearing temperature are too high. This is due to the loosening of fixed bolts on reducer or both ends of reducer bearing burn out, here you need to loosen the coupling on both sides of reducer ,correct and install.

 

Debugging of Screw Conveyor

Debugging of Screw Conveyor

All the hanging bearings of screw conveyor should be hanging on the connecting shaft reliably without stuck and bending of screw. When installation, adjusting the gaskets number of hanging bearing to make no gap in subdivision surface while a proper radial gap between bearings and connecting shaft.

 

Hanging bearing should be installed in the center of connecting shaft, the distance between end face and two screw pipes should be over 10mm when D≦400mm and over 20mm when D≧500mm.

To adjust the accumulative error between chassis and screw, there should be padding asbestos lining between the flange of the chassis when installation. Padding waterproof canvas between chassis and cover according to the requirements for sealing.

 

When the difference of center heights of driving gear reducer shaft at low speed and screw conveyor is too much, using the gaskets to adjust the height of driving unit.

 

When no-loading running, if there is oil leakage phenomenon, removing the bearing and adjusting the tightness of spring in sealing ring until no leakage.

When no-loading running, overheating of hanging bearing indicates the installation position of hanging bearing is improper which leads the locking of connecting shaft, there should be loosing the fasten bolt and adjusting the position of hanging bearing.