1) About the Compression Ratio of the ring die mould.
define "L" as the effective hole length of the ring die.
define "D" as the effective hole diameter of the ring die.
the Compression Ratio = L / D.
The higher Compression Ratio, the more compact that the animal poultry feed pellet will be, and the pelleting speed will be reduced accordingly.
2) Analyze the reasons for the ring die failure
Pellet mill machine is the key equipment in poultry and animal feed pellet producing process. The ring die mould is the heart part of pellet mill machine, and it's one the most easy wearing spare parts as well.
Since the ring die mould work with friction all the time. the ring die mould will be wearing and finally failure along with the throughput increasing. the handling capacity is one of the main performance index for the ring die mould.
theoretically, one set of ring die mould and one pair of press roller could produce 2000 ton and 500 ton feed pellet. but in practice, even the poultry and cattle animal feed factory whose management were very well could reach to 1500 ton and 300 ton respectively. and for those poor-management one, the value is only 600 ton / 100 ton.
After a period of working, the hole inside wall friction losses was increasing.
A) the diameter of the hole increased, and the diameter of final product animal feed pellet exceed the specified value.
B) the scraggly of the hole inside wall get worse, the feed raw material will easy to block, the capacity will decrease.
C) the thickness of the hole wall will be reduced, the structural strength will be highly reduced.
3) A number of reasons cause the ring die friction losses.
A) the fineness of the chicken poultry cattle animal feed raw material.
the more fineness of the raw material, the bigger superficial area of the raw material, and the feed raw material will more easily to absorb water from the steam, it's propitious to conditioning and forming.
otherwise, too coarse granular size of the chicken poultry cattle animal feed raw material will increase the friction losses of the ring die.
Generally, all of the feed raw material partical size should be more than 8 mesh, the proportion of partical that above 25 mesh should not less than 65%.
for those high coarse fiber feed raw material, we should add some oil to reduce the friction, and the surface of the final poultry animal feed pellet will look more smooth.
B) the impurity in the raw material will accelerate the friction losses. hence the raw material cleaning is very important.
C) steam could soften the raw material, and make the oil content cell division, the oil in the cell will play a role of lubrication when pelleting, and the capacity will be increased.
Normally, the pressure of steam should be 0.2-0.4 MPa.
for those high protein material, the pressure should be less accordingly.
for the rich fiber material, the steam pressure should be higher.
under the function of steam, the water content in the raw material should be 16%-17%. the temperature should be 78-87 Celsius system.
D) the space between the press roller and the ring die mould.
It will speed up the friction if the space is too small. the ideal space is 0.2-0.4 mm.
the space selection will depend on the diameter of the pellet. smaller diameter, smaller space.
when we replace the ring die mould with a new one, the space should be set as lower value.