Failure of underwater granulator and improvement measures（3）
Improvement Measures
Improvement measures for fixed knife
The originally fixed knife is made of integral Crl2MoV material. Due to the limitation of heat treatment conditions, the hardness of the knife is unstable.
The hardness of the fixed knife changed to ceramic material has been greatly improved, and the wear is slow.
The operating cycle of the pelletizer has been increased from 5-7 d to 15 d (when a single unit is running), and the effect is remarkable.
Also, when the outer diameter of the movable knife was reduced from 162.5 mm to the limit size of 157 mm, we adopted the method of adding 1-15 mm spacers between the fixed knife and the fixed knife holder, which not only prolong the life of the movable knife but also avoided Irregular cutting of pellets due to material clamping.
Resharpening of movable knives
It turned out that we had always sharpened the movable knife by ourselves.
Due to the limitation of the abrasive tool, the front and back angles were not able to be sharpened, which caused the deterioration of the appearance quality of the cut pellets. Later, we sent it to Shanghai Lida Company for grinding to correct the front and rear angles.
The repaired movable knife can meet the needs of working conditions.
Renovation of the casting lead
In the past, there was 1 casting head and 2 pelletizers, which had to be switched back and forth.
The load of a single pelletizer is 100-150 t/d, the operating cycle is about 15 days, and the discharge flow is large. After being transformed into a double casting lead, the load of a single pelletizer is 50-80 t/d, the operating cycle is increased to 30 d, and the discharge flow is small.
At the same time, a new pelletizer was added to speed up the replacement of the preparation table, thereby saving production time.
Quote-[1] Fang Cheng, Dong Zijun. Troubles and improvement measures of underwater pelletizer [J]. Polyester Industry, 2005, 018(006): 41-43
