There are two different styles of stationary mixer. The most popular style charges into one end and discharges out of the opposite end. It is easier to perform dust collection with this model because of a small amount of air resistance in the way of the materials. The second style is charged and discharged through the same end.
Each brand of mixer is very similar. The only difference is in the tilting mechanisms. The producer tries to keep this design as simple as possible in order to keep maintenance costs down.