What Should be Done if Double Disc Refiner Fails?

Double Disc Refiner is the most critical equipment for high-yield pulping. Usually the pulping area is composed of moving disc and fixed disc. It can be used as defibrator or medium and high concentration refiner, with advantages of high capacity and low energy consumption , little fiber loss and so on. So what should we do when the refiner fails during operation?

During operation, method of combination of manual inspection and on-line monitoring is used for diagnosis of disc refiner failure, manual inspection person is responsible for the monitoring and inspection of the bearings, high voltage junction box and other parts with experience combined with vibration measuring instrument and temperature measuring instrument, and comprehensive analysis and judgment of the fault situation; online monitoring is to do analysis and judgment of the various data collected by the system chain control.

The common faults of Double Disc Refiner are as followings.

I. The Vibration of the Double Disc Refiner

1. Too large deviation of coaxiality of the Double Disc Refiner and motor coaxial degree can cause vibration, so after running for some time, it is necessary to release the gear coupling, and use a dial indicator for calibration and reset.

2. If the newly replaced cutting disc vibrates after the start , there may be two reasons, one is moving disc is not balanced, it is necessary to re-replace the cutting disc; second is the large deviation of parallelism of the fixed disc and moving disc, vibration will be large after loading, it is necessary to adjust the disc and tighten the screws, and check if the parallelism of the two discs is within the range;

3. The vibration caused by too large installation gap of the bearings or bearing damage can be determined through listening with copper tube or check with vibration measuring instrument;

4. For vibration caused by flexibility deformation of the cantilever shaft of the movable disc, timely replace the main shaft;

5. If the gear grinding is broken by the hard objects and caused vibration, it will affect the quality and output of refining, it is necessary to promptly replace the grinding disc.

II. If hard objects enter the refiner, there will be different noises.

If it is small metal object, there will be harsh sound, gap of cutting disc should be adjusted as soon as possible; if it is larger hard object, the refining should be immediately stopped, and the refining chamber should be opened for inspection and treatment.

III. The disc is in a dilemma.

If there is unsteady advancement and retracting, first of all, give up the hydraulic cylinder, and then check the hydraulic station oil level, and check if the cylinder piston rod is stuck.

IV. Refining capacity decreases.

If the refining capacity decreases by 30%, the cutting disc must be replaced, which is the principle of replacing cutting disc. The main reasons are as followings: gear grinding in crushing area is broken or the gear groove of the cutting disc is plugged; cutting disc has been used for a long time, there is serious wear; screw feeder blade deformation is serious, feeding is difficult, and so on which will cause decline of the refining capacity.

V. The quality of the refining is not good.

The reasons are as follows: grinding gap is too large; grinding concentration is too small; cutting disc wear is serious; cooking temperature is low, the degree of softening of the material is not enough; slurry washing is not good, viscosity is high, and so on.