Ribbon type mixer

Rhovanil fine mesh vanillin, 25 550, 552 Rhovanil free flow vanillin, 25 550 Ribbon silicon, 23 40-41 Ribbon Thermal Shock Test, 21 513 Ribbon-type mixers, 16 719-720 in bar soap manufacture, 22 751 Riboflavin, 25 796-797 Ribonucleic acid probes, 14 153 Ribonucleic acids (RNAs), 12 449 ... 

Paddle Type. This type is similar to the ribbon type except that interrupted flight blades or paddles transfer materials from one end to the other, or from both ends to the center for discharge. The paddle-type mixer can be used for dry materials or pastes of heavy consistency. It can be jacketed for heating or cooling. 

Dry products can include dusts, powders, and granules. Dusts and powders are manufactured by mixing technical grade material with the appropriate inert carrier and grinding the mixture to obtain the correct particle size. Several rotary or ribbon blender-type mixers mix the product. Figure 6 shows a typical dry formulation unit for pesticides [8]. 

Mixing Mechanisms Consider a calendering process for manufacturing PVC floor covering. The line consists of a ribbon-type blender in which the PVC is dry-blended, and an internal mixer that feeds a SSE equipped with a static mixer, feeding the first nip of the calender. What types of mixing mechanisms does the polymer experience Specify the locations at which each mechanism occurs. 

Anchors, helical ribbons and screws, are generally used for high viscosity and non-Newtonian hquids. The anchor and ribbon types are arranged with a close clearance at the vessel wall, whereas the helical screw has a smaller diameter and is often used inside a draft tube to promote liquid motion through out the vessel. Helical ribbons or interrupted ribbons are often used in horizontally-moimted cylindrical vessels. A variation of the simple helix mixer is the helicone (Figure 8.27), which has the additional advantage that... 

The mixer in the slurry surfacing machines is either a double-shafted pugmill (more common) or the ribbon type, from which the slurry is discharged into a spreader box. 

Mixing can be accomplished in ribbon blenders and drum tumblers however, a plough-type mixer is suggested. This type mixer can produce a homogeneous blend in a short time (15-30s) with undue fiber breakage. 

Typical batch mixers include planetary mixer [shear] blade (Helen) mixer [convection shear] blade (double-arm) mixer [convection shear] paddle (pan-type) mixer [shear] paddle (Marion) mixer [shear diffusion] tumbler (drum) mixer [shear, diffusion] tumbler (double-cone) mixer [shear] tumbler (twin-shell) mixer [shear] Muller mixer [shear] mill mixer [shear] ribbon mixer [convection diffusion] vertical spiral mixer [convection diffusion] Nautal mixer [convection diffusion] Banbury mixer [shear] airmix mixer [convection diffusion] Lodige mixer [shear diffusion] gravity mixer [convection] and vibratory mixer [convection shear]. 

Fig. 2. View of interior of ribbon type powder mixer in operation (Courtesy of ICI (Hyde) Ltd.)...

Fig. 37. Various mixer types for dry soflds (a) the V-mixer, (b) ribbon blender, (c) vertical screw mixer, and (d) Nautamix.

Figure 10.15. Some mixers and blenders for powders and pastes, (a) Ribbon blender for powders, (b) Flow pattern in a double cone blender rotating on a horizontal axis, (c) Twin shell (Vee-type) agglomerate breaking and liquid injection are shown on the broken line, (d) Twin rotor available with jacket and hollow screws for heat transfer, (e) Batch muller. (f) Twin mullers operated continuously, (g) Double-arm mixer and kneader (Baker-Perkins Inc.), (h) Some types of blades for the double-arm kneader (Baker—Perkins Irtc.).

Numerous equipment types can be used for agglomeration, including horizontal ribbon and vertical mixers, rotary drums, zig-zag mixers, and pan agglomerators. Horizontal ribbon mixers as shown in Fig. 36.41 are used primarily for dry mix formulating, where only limited agglomeration occurs. They are comprised of a U-shaped trough and a ribbon or paddle-type agitator. Liquids are sprayed onto the surface of the dry material and slowly dispersed into the mix. Mixer operations can be either batch or continuous. 

There are several types of mixers helical ribbon, ribbon bar or paddle mixers. 

Convection blenders reorient groups of particles in relation to one another as the result of mechanical movement, for example, caused by a paddle or a plow. As a result, circulation patterns result in this type of blenders. Subclasses of convection blenders are typically defined by vessel shape and impeller geometry. Ribbon blenders (Fig. 30), planetary blenders (Figs. 31 and 32), orbiting screw blenders (Fig. 33) are examples of convection blenders. High shear mixers comprise another sub-class of convection blenders that will be discussed separately. 

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