Werner Pfleiderer

The incorporating process is carried out in mixing machines of the Werner Pfleiderer type, that is with two heavy horizontal blades in a specially shaped bowl. Incorporation consists of mixing the alcohol wet nitrocellulose and other ingredients with a solvent, normally ether and alcohol mixture. The amount of solvent used is adjusted so that the final consistency is that of a stiff dough. 

Wentworth process, for ethanol separation from water, 8 834-835 Wenzel s equation, 22 111-112 Wenzel contact angle, 22 111 Werner nomenclature scheme, 17 391-392 Werner-Pfleiderer (WP) Compounder, 22 44 Werner-type inclusion compounds, 14 171-172... 

The main problem with nanofillers is the need for complete exfoliation. Some special compounding techniques have been developed such as, for example, the ZSK MEGA compounder by Coperion Werner Pfleiderer with a special screw configuration. 

Hexoplast 75. A plastic explosive, developed during WW II at the Krummel Factory of Dyna-mit AG. It contained RDX 75, NC 1.2 to 1.4, liquid DNT 20.0 and TNT 3.8 to 3.6%. This mixture was prepd by heating the required amount of RDX to 90° in a Werner-Pfleiderer mixer, and blending it with a small amount of... 

The freezing point of a TNT and DNT mixture was - 20°C. The ingredients were mixed in a Werner-Pfleiderer kneader at 90°C, the cyclonite with the nitrocellulose being added first and nitro compounds added after thorough mixing. This prevented the formation of lumps of swollen nitrocellulose. 

The final mixing takes place in a large Werner-Pfleiderer (or Baker-Perkins) type sealed mixer of the type extensively used in smokeless powder manufacture (Fig. 206). A capacity up to 2000 lb is used in the case of thiokol propellants. After the premix has been added to the mixer, the finally ground oxidant is added. This material is conveyed to the mixer in a closed container and is added so that the... 

Hot mixing may be conducted either in kneaders of the Werner-Pfleiderer type with a heating jacket or in disk mixers (Fig. 167). These mixers consist of a round plate of copper, brass or bronze, approximately 2 mm dia., with beaded edges, which is heated with hot water to a temperature of 80-90°C. The material is mixed with bronze blades and kneaded with a bronze roller. 

Medard and Le Roux [1] examined the influence of various methods of mixing on the properties of ammonium nitrate explosives ( Explosifs du type N ). They found that mixing in heavy (5 ton) edge-runners gives explosives of higher sensitiveness and rate of detonation than the same explosives mixed in kneaders of the Werner-Pfleiderer type. 

For the manufacture of dynamites, kneaders of the Werner-Pfleiderer type may also be employed. They are widely used in the manufacture of smokeless powder (Fig. 206). Drais kneaders however, have the advantage over the Werner-Pfleiderer type in that they are safer to handle, and hence more suitable for mixing materials sensitive to friction and impact, such as dynamites. 

In Werner-Pfleiderer kneaders this distance is very small so that if a hard object (metallic part, screw, nut etc.) penetrates into a kneader, an explosion may occur due to seizing. Werner-Pfleiderer kneaders have a capacity of 50-200 kg of dynamite. 

The manufacture of perchlorate explosives is similar, but due to the lower sensitiveness to impact of perchlorate explosives, some operations as e.g. mixing, may be conducted in Drais kneaders (Figs. 173-175) or even in kneaders of Werner-Pfleiderer type (Figs. 206-208). 

Fig. 207. Wemer-Pfleiderer kneader at work (Courtesy Werner Pfleiderer, Maschi-nenfabriken und Ofenbau, Stuttgart). 

Fig. 209. View of paddles (Courtesy Werner Pfleiderer, Maschinenfabriken und...

The advantage of kneaders of the Chaudel-Page type is that they take up considerably less space than Werner-Pfleiderer kneaders. Premises which provide accommodation for six kneaders of the Chaudel-Page type can hold at most three Werner-Pfleiderer type kneaders. 

The moment of unloading is particularly dangerous since large quantities of ether vapours mix with the air to form an explosive mixture. At this moment any impact of metal against metal which may produce sparks is dangerous (e.g. allowing the heavy lid to strike against the rim of the kneader in the Werner-Pfleiderer system). 

The cordite paste so obtained is next loaded into Werner-Pfleiderer kneaders where it is incorporated with vaseline and acetone. The quantity of acetone in relation to the nitrocellulose is 50-60%. Kneading lasts for 2.5-3.5 hr. 

A ZSK-type double-screw mixer proposed by Werner Pfleiderer (Table 3)28) adapted to manufacture solidified moulding compounds. 

Table 3. Specifications of Werner Pfleiderer Double-Screw Mixers manufactured in FRG...

The leading firms in developing and employing the aforementioned techniques are Buss, Werner Pfleiderer, Berstorff, and some others. 

Extruded Corn Meal with Thiamin Added. Degerminated yellow corn meal with 0.5% thiamin HC1 was extruded on a Werner Pfleiderer ZSK-30 co-rotating twin-screw extruder. The five heating zones of the barrel were held at 50°C, 76°C, 100°C, 134°C and 172°C, respectively. The product temperature was 180°C, the torque was 46% at 200 RPM and the pressure was 130-172 psi. The extrudate was allowed to cool to room temperature, then stored in glass vessels under nitrogen at 4°C. 

When 0.5% thiamin hydrochloride in degerminated yellow corn meal was extruded on a Werner Pfleiderer ZSK-30 co-rotating twin-screw extruder at the final product temperature of 180°C, numerous volatile components were generated. Table II lists the volatile compounds isolated and identified by purge-and-trap GC/MS method. 

The extruder shown in Figs. 1.2 and 1.3 has been restored by Coperion Werner Pfleiderer and is on display. 

As a laboratory and trial machine, the machine shown in Figs. 1.2 and 1.3 has no guards in order to provide easy access and be readily convertible. In contrast, the machines sold by WP (then known as Werner Pfleiderer, but today called CWP, Coperion Werner Pfleiderer) were fully enclosed in the fashion of the day see Fig. 1.4 which shows two ZSK machines from the 1950s. Initially, WP also built the ZSK machines with a vertical screw arrangement, as the sectional drawing in Fig. 1.5 shows. The figure also shows that the actual processing section is very small in relation to the drive unit. At that time, the machine brochure promoted the oversized drive (with reliable operation as the benefit). 

Figure 1.6 Screw compounders sold by Coperion Werner Pfleiderer for various products (Source CWP)...

After the license was awarded to Werner Pfleiderer (Section 2.3.3) and after an initial warm-up phase, machinery and process engineering underwent dramatic development. This took place during the years of industrial development and the simultaneous advances in the areas of polymer chemistry and plastics engineering that were taking place at the same time (example compounding technology). Five major developments characterize this boom ... 

Approximately 5000 co-rotating extruders of all types and sizes have been produced so far by Werner Pfleiderer. 

Figure 2.30 Modular technology in screws (Courtesy Werner Pfleiderer)...

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