Dosing of high-temperature heavy-flowing powder with a wide discharge
Task
Our customer works with a poorly flowable-heavy (4 kg / dm³) powder mixture, which must be dosed at about 150 °. The dosage should be carried out continuously with about 50 kg / h on a shear roller. The product tends to form large lumps and build bridges in the dosing tank. Another problem is that the metering on the shear roller must not be selective, because the product then forms a mountain above the roller, which cools and interferes with the rolling process. Previous attempts with a screw device, which was complained on a swivel arm, failed. In addition, the problem for our customer is that the dosing container is regularly filled with product from a mixer. The process is not automated, so the refill is done by hand and interferes with the gravimetric dosing process.
Execution
We analyzed the process in detail with the customer and discussed different solutions. We worked intensively with the plant operators and the process engineers. With all the data in the luggage, we have developed a prototype. The core of the solution is a vibrating conveyor trough with a width of 30 cm.
Due to the width of the channel, the heavy roll can be fed directly and evenly, a pivoting construction, which was necessary in Schneckenendosiergerät, can be omitted. In the geometry of the dosing tank very steep container walls in combination with external discharge aids have contributed to the solution. In order to ensure the trouble-free refilling we have used the shock detection of our control. Each filling process greater than 500g is detected as an external disturbance, our control changes automatically for a few seconds from gravimetric to volumetric dosing, and back again.
Result
Due to the uniform and continuous dosing, the customer can drive the heavy roller much faster and has next to a trouble-free dosage also achieves a higher plant capacity. Dosing disturbances during manual refilling are a thing of the past.
