Kneaders

Kneaders Kneading Kneading mixers Knecht compound Knecht method Knife mills Knight and Allen Knives Knize Ten Knockdown Knockdown resistance... 

Fig. 38. Various mixer types for viscous pastes (a) the change-can mixer, (b) rake mixer, (c) double-rake mixer, and (d) sigma-blade kneader.

The second process to finish phthalocyanine, which is more important for P-copper phthalocyanine, involves grinding the dry or aqueous form in a ball mill or a kneader (64). Agents such as sodium chloride, which have to be removed by boiling with water after the grinding, are used. Solvents like aromatic hydrocarbons, xylene, nitrobenzene or chlorobenzene, alcohols, ketones, or esters can be used (1). In the absence of a solvent, the cmde P-phthalocyanine is converted to the a-form (57,65) and has to be treated with a solvent to regain the P-modification. The aggregate stmcture also has an impact on the dispersion behavior of a- and P-copper phthalocyanine pigments (66). 

Reverse cleaners Kneader Reverse cleaners Reverse cleaners Reverse cleaners... 

Batch Saponification. Batch saponification, the oldest PVA manufacturing method (252), is mainly used in the 1990s for the production of specialty products. The process uses a kneader in which the hydrolysis, washing, and drying operations are performed. This is the simplest method of saponification, but the production rates are low, and producing the product quaUty needed by many end uses is difficult. 

Dmg loading can be accompHshed by dispersion or adsorption. In dispersed systems, a dmg is blended into a polymer by mechanical means, such as a kneader. The viscosity of the polymer, and the size and concentration of the dmg, need to be optimized to minimize aggregates. Dmgs can also be absorbed by equiUbrating a polymer in a dmg solution. The absorption rate can be accelerated by introducing an appropriate solvent to swell the polymer. AH solvents would then have to be removed. 

FIG. 18-41 Agitator blades for double-arm kneaders a) sigma (h) dispersion (c) miiltiwiping overlap (d) single-curve (e) doiible-naben. (APV Baker Ferkins, Inc.)... 

Working capacities range from 4 to 3800 L (1 to 1000 gal), with up to 300 kW (400 hp). This type of kneader is offered by most of the double-arm-kneader manufacturers. It is particularly suitable when a heel from the prior batch can be left without detriment to succeeding batches. 

FIG. 18-42 Typical application and power for doiihle-arm kneaders. To convert horsepower per gallon to kilowatts per ciihic meter, multiply hy 197.3. [Farket] Chem. Eng. 72(18) 125 (1965) excerpted hy special pomission of the copytight owner, McGraw-Hill, Inc.]... 

Extrusion compounders such as the Buss Ko-Kneader have been used for mixing phenolic resins. It is elaimed that they produce in some respects a better produet and are more eeonomical to use than mill-mixers. 

Offner, m. opener (Paper) pulper, kneader. Offnimg, /. opening aperture, orifice, mouth ... 

It is usually done by computer controlled electronic weighing scales that supply precise amounts of each ingredient to a high intensity mixer. The still-dry, free-flowing blend is then charged to a feed hopper where it is screw fed into a continuous mixer such as an extruder and/or kneader. Under the action of a mixer s reciprocating screw in the confined volume of the mixer chamber, the blend begins to flux or masticate into the required plastic state. 

Bulk Material Processing Leaders Feeders Blenders Dryers Kneaders... 

Lehalleur (Ref 2) states that Energit can be prepd by wetting small grains of double-base proplnt in a kneader with equal quantities of such volatile solvents as acet and furfural, adding liq aromatic nitrocompds and other ingredients, and then kneading the mixt until it is thoroughly blended. Finally, the solvents were removed by evapn (See also Ref 4, Ger 42-L)... 

Kneaders, Z- and sigma-blade, and Banbury mixers as shown in Figure 7.20, are generally used for the mixing of high-viscosity liquids, pastes, rubbers, doughs, and so on. The tanks are usually mounted horizontally and two impellers are often used. The impellers... 

Most plastics e.g. polyolefins and polystyrenes and their derivatives such as ABS (acrylonitrile-butadiene-styrene) and SAN (styrene-acrylonitrile) are supplied by the manufacturers in ready-to-use form with most of the above-mentioned stabilizers or simply need to be additionally stabilized with other additives, e.g. antistatic agents and HALS stabilizers, as required. On the other hand, in the case of other materials (e.g. PVC) it is the end user who adds the additives, pigments or preparations. This is normally done on fluid or high-speed mixers, although in the past gravity mixers or tumble mixers were also used. The mixture is then homogenized on mixing rolls, kneaders, planetary extruders or twin-screw kneaders and further processed. 

The pigments are incorporated into the resins before crosslinking to ensure homogeneous coloration. This can be done in the molten resin, for example in a kneader at about 90°C, or in dissolved or liquid resins by the liquid resin method. Ball mills are normally used for coloring prewetted powder molding compounds that have not yet been cured. 

Baking is currently performed by continuous operation. Modern variations involve using heated crushing or milling equipment, such as kneader dispersers or oscillating mills at approximately 200°C [9]. This technique significantly improves the reaction control over a batch process. If baking is performed by continuous process, phthalonitrile only remains within the reaction vessel for a very short period of time (between 3 and 20 minutes). It is important to remember that the temperature may not exceed 250°C. The product which evolves from this process is usually purified by acid treatment. 

Production of the crude pigment is followed by finishing. The options include milling the material with salt in a ball mill in the presence of an organic solvent, or treating it similarly in a kneader, or producing a 60 to 90% sulfuric acid slurry, or using aromatic sulfonic acids. 

While the Dove composition described in Table 9.4-2 was processable at reasonable line speeds on a conventional soap processing line (roll mills, extruders, stampers), some equipment modifications were necessary. For example, whereas soap is normally mixed in large agitated tanks, the Dove mixture had a much greater viscosity and therefore required use of a steam-jacketed kneader mixer such as those used to make bread dough, pastes or mastics. 

An apparatus for mixing solid ingredients in the presence of liquids. Several types were used in Ger for mixing proplnts expls, such as the Columnar type (Saulenknetmaschine) (Ref 2, pp 105—06 Ref 3, p 237) Wemer-Pfleiderer Misch-und Knetmashine (Ref 1, p 75 Ref 3, p 227 Ref 4, pp 585—87), and others. In France, Chaudel-Page kneaders are in general use (Ref 4, pp 588—9)... 

In the Fr method, also known as "mouiage", the colloided NC, previously mixed in a kneader with other ingredients of propint, is forced, by mean5 of hydraulic pressure of about 300 kg/sq cm, thru slots (of different widths and thickness for each type of pro pint), from which it emerges in the form of ribbons. They are then cut into strips of a length convenient for loading into the gun for which the proplnt is intended. These proplnts are known as "poudres lamellaices . For the formation of tubular proplnts (seldom used in France), the colloided mass is forced in the die into the space which surrounds a centrally fixed steel wire... 

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