The red line depicts the residence time of the mixing goods during a continuous boiler flow. The green line depicts the residence time of the mixing goods during a pipe flow.
Please also read our blog post: "Continuous mixing versus batch mixing"!
In the case of continuous mixing, a distinction is made between the pipe flow and the boiler flow. In practice, there are also hybride forms of both processes.
If the mixing takes place in the form of the pipe flow, then the continuously introduced components are conveyed from right to left. Mixing tools convey and swirl the mixing goods. The principle of "first-in-first-out" applies here. The mixing effect is intensified when individual tools convey against the flow direction. An increased degree of filling is present there. The more return conveyance takes place, the longer the residence time. Increased return conveyance also requires increased energy input.
In the case of continuous boiler flow, the main flow direction is determined by gravity. A helical mixing tool distributes the mixed goods particularly effectively by conveying them upwards. A very high mixing quality is already achieved after just eight revolutions. The raw material components are continuously fed into the mixing chamber from above and flow into the completely homogenized mix bed. They are randomly distributed in the mixing room. A constant filling level is set in the mixing chamber, which can be between 40% and 80%, for example.
Boiler flow in this context refers to the fact that almost all components are present in homogenized form in the mixing chamber. Raw material components are added continuously. They are added in the correct ratio and their volume flow is comparatively small. The mixing efficiency is calculated in such a way that they are homogenized after a few seconds in the mixing chamber.
Response from amixon®: There is no general answer to this question. Both systems have specific advantages. It always depends on the respective application.
The pipe flow is always preferable
to the boiler flow:
Boiler flow is to be preferred to pipe flow