What you should know about selecting and maintaining a single-shaft batch ribbon mixer
Because it can mix almost any bulk solids together, the ribbon mixer is considered the workhorse of solids-solids mixing. The unit can also mix small amounts of liquids into a solid. The ribbon mixer can operate continuously or in batches and with one or two mixer shafts. This article introduces you to the single-shaft batch ribbon mixer. After explaining how the mixer works and describing ribbon assembly variables, construction materials, and equipment configurations, the author provides information on how to select and maintain the mixer. Related information specifies what you need to tell the mixer manufacturer about your mixing needs during the selection process.
A single-shaft batch ribbon mixer is shown in Figure 1. The unit consists of a horizontal, U-shaped vessel, called a tub or trough, that is equipped with a rotating shaft powered by a drive. The shaft, which is mounted at the tub's end plates, is fitted with metal spokes and inner and outer helical blades called ribbons; together, the shaft and attachments form the ribbon assembly, shown in Figure 2. [In some units, the shaft has paddles or plows.] The clearance between the outer ribbon tips and the tub is typically 1/8 to 3/16 inch, depending on the manufacturer.