EBERHARDT Maximat spiral mixers were first introduced at the 1968 IBA held in Stuttgart and at that time were equipped with a round shaped spiral arm.
The introduction of innovative technology saw Eberhardt change the spiral arm from a round profile to a square profile in 1986, set in such a way as to always have an edge (not a face) showing to the bowl wall when in close proximity. They are now available from Symetec .
The square profile proved to reduce both the power required to mix the dough but more importantly, reduced heat rise in the dough.
It was found that the round profile pressed the ingredients and the dough against the wall of the bowl. With both the arm and the bowl rotating, this caused excessive friction, which mandated a powerful motor and in turn caused rapid heat rise with the squashing and tearing of the dough between the two surfaces.
In contrast, the square profile has the same sectional area as a round arm, but a reduction of 19% in the mating surface area between spiral arm and bowl provided less squeezing and friction as the dough is mixed and worked by the rotating spiral arm. This is especially beneficial when mixing wheat doughs.
The Maximat square profile spiral arms with four flat faces are also found to better collect ingredients and gather them into the mix providing a further improvement in distribution and mixing time without heat rise compared to a round profile arm.
Another excellent benefit is the considerably reduced damaging effect when raisins, other fruits or nuts are added to the dough.