Kneaders, cost

Karbate, 440-442 Kel-F, 435 Kettles, cost of, 731 Kneaders, cost of, 559 Koroseal, 435... 

Further, the use of aqueous additive systems eliminates dust and compaction problems associated with the handling of powder form additives. Finally, the use of aqueous additive systems provides flexibility for mixing the additive with the resin. The additive can be mixed and dried with the resin still in moist, wet-cake form. It can be blended with other formulation ingredients, or pumped into an extruder or kneader during the compounding step. This flexibility can, in turn, provide still lower-cost processes and improved uniformity of mixing. 

Although most solid propellants are manufactured in a vertical mixer batch process, a continuous mixing process has been used successfully in the production of the first stage A-3 Polaris propellant and in the NASA 260 inch demonstration motor program. The use of a continuous mixing process, in which propellant chemicals are metered into a helical kneader, offers considerable benefit in terms of safety and cost for large-volume propellant production. 

Cost data for blenders and mixers, kneaders, centrifugal separators, crystallizers, crushing and grinding equipment, dust collectors, electrostatic precipitators, and screens are presented in Figs. 14-66 through 14-88. 

Cost of kneaders. Price includes machine, jacket, gear reducer and drive, cover, nozzles, and agitator. Motor and starter are not included in purchase price. 

The undiluted silane is added directly to the polymer before or together with the filler. It is essential that the resin does not prematurely react with the silane as otherwise the coupling efficiency will be reduced. Typical compounding equipment consists of internal mixers, kneaders, Banbury mixers, two-roll mills, or extruders. The integral blend technique is widely used in resin/filler systems because of its great simplicity and possible cost advantages. This is mainly due to the one-step process and the lower raw material costs (untreated mineral plus silane compared to pretreated mineral) despite the fact that more silane is needed to achieve comparable performance in the finished composite. 

Table 14.6 Cost Price Evaluation per Metric Ton Terpolymer of MMA, HEMA, and n-BA. Extrusion Reaction in One Buss Kneader with a Diameter of 200 mm...

Because of the accuracy of the calculation method only an estimation of the cost comparison can be made, but from the results of these calculations it can be seen that reactive extrusion can be competitive with conventional processes. Reactive extrusion with one kneader with a diameter of 200 mm is economically more attractive when compared to a batchwise solution polymerization for a capacity of 5000t/year. When calculated with the... 

Evolving gas from viscous liquids in bubble reactors may give rise to viscous foams and entrainment that will limit the reaction rate, especidly on a larger scale. A spray column may be the first alternative (section 4.6.2.1). If cooling is also required effective measures are costly. For this purpose thin film evaporators (section 4.63.1) or scraped surface evaporators can be effective. For very viscous liquids one may consider batch kneaders or extruders with vapour ports. 

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