Transfer mixer

The cavity transfer mixer (CTM) is a distributive mixing device used as an add-on unit to extruders the barrel and screw have hemispheres cut out of their surfaces to give an overlap of half a pitch. 

Wang, C. and Manus-Zloczower, I., Flow Field Analysis of a Cavity Transfer Mixer, Polym. Eng. ScL, 34, 1224 (1994)... 

Fig. 23. Screw sections for enhancing distributive mixing in single-screw extruders (a) Dul-madge mixer, (b) Saxton mixer, (c) pin mixer, (d) pineapple mixer, (e) cavity transfer mixer, (f) slotted screw flight, (g) Kenics and Ross ISG static mixers [148]...

See heat transfer. Section 16.11.3.5, and mixing. Section 16.11.7.3. For gas reactions example oxidation of ammonia to nitric acid, production of maleic anhydride, xylene, styrene, vinyl chloride monomer, ethylene dichloride. UD for mass transfer mixers 6 1 to 20 1. Gas velocity for turbulent flow. For gas-liquid reactions cocurrent mass transfer in bubble flow gas superficial velocity 0.6 to 2 m/s liquid superficial velocity 0.3 to 3 m/s spray flow gas superficial velocity 3 to 25 m/s see size reduction. Section 16.11.8.1. For liquid-liquid reactions dispersed phase drops diameter 100 to 2000 j.m, with diameter decreasing as the velocity increases, the surface tension decreases, and the hydraulic radius of the mixing element decreases surface area 100 to 20,000 m /m, depending on the drop diameter and the concentration of dispersed phase. Turbulent flow. Example reactions as a PFTR polymerizations of polystyrene, nylon, urethane sulfonation reactions and caustic washing see size reduction. Section 16.11.8.3. 

Add-on s — Barmag add-on torpedo, Staro-mix , Maddox, Cavity Transfer Mixer (CTM), Twente Mixing Ring (TMR), the Extensional Flow Mixer (EFM), Dynamic Melt Mixer (DMX), static or motionless mixers (SM) from Koch, Ross, or Kenics, etc. 

No design data on mass transfer Mixer-settlers ... 

Figure 7.18 Cavity transfer mixer (Courtesy RA PR A, Shrewsbury, UK)...

For gas reactions Example oiddation of ammonia to nitric acid, production of maleic anhydride, xylene, styrene, vinyl chloride monomer, ethylene dichloride. L/D for mass transfer mixers 6 1-20 1. Gas velocity for turbulent flow. 

Cavity-transfer mixer n. A two-piece device installed at the end of an extruder screw to accomplish both distributive and dispersive mixing. The stator is a barrel extension into whose inside surface is machined an array of many hemispherical cavities. The rotor is a screw extension whose exterior is similarly contoured. The lands of rotor and stator have the usual close clearance of screw and barrel. As the melt steam passes through, it is smeared between the lands and is repeatedly cut into small globs and recombined, passing from rotor to stator, stator to rotor, until it emerges. 

See also Dulmadge mixing section, Maddock mixing section, and cavity-transfer mixer. 

Cavity Mixers. One of the well-known cavity mixers is the cavity transfer mixer (CTM). It consists of a screw section and a barrel section, both containing hemispherical cavities (see Fig. 51). 

Internal modifications. Here belong the screw modifications, as well as the devices that need to be attached to the screw, e.g., Barmag s torpedo, RAPRA s cavity transfer mixer (CTM), a multi-screw planetary unit. All three examples also require modification of the corresponding barrel section. By contrast, the developed in the University of Twente torpedo with perforated, freely rotating sleeve, can be used without affecting the barrel, e.g., to improve mixing of the injection molding extruders. 

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