Diskpack

The CDP was commercially developed into a processing machine by the Farrel Corporation of Ansonia, CT, USA, under the brand name Diskpack. 

The CDP was developed by the Farrel Corporation in Ansonia, CT, and sold under the trade name Diskpack. Although over a dozen machines were manufactured, sold, and used in industry, the line was discontinued. A retrospective analysis of this development, which is instructive regarding the uphill battle of many engineering innovations that radically depart from the traditional practices, is given in Z. Tadmor, Machine Invention, Innovation and Elementary Steps, Adv. Polym. Technol, 21, 87-97 (2002). 

Fig. E9.7a A schematic but representative design of a 350-mm-diameter, 12-chamber Diskpack compounder. The rotor is shown at the top and the cross section of each separate chamber is shown in the sequence of the processing path. Each cross section shows the housing, the inlet and outlet, and the various inserts attached to the housing. [Courtesy of Farrel Corporation, Ansonia, CT.]...

This particular Diskpack machine had only four melting chambers. 

Reactive processing is limited to polymerization or chemical reactions of polymers in conventional singlescrew or twin-screw extruders, excluding processes in oscillatory kneaders, Banbury-type continuous mixers, or Diskpack equipment. Emphasis is placed on continuous processes that have been implemented commercially or that can serve as models for commercial purposes. 

There are several extruders that do not use an Archimedean screw for transportation of materials, but still belong to the category of continuous extruders. These machines are sometimes referred to as screw-less extruders. Usually they employ a disk or a drum. Most disk extruders are based on viscous drag transport principle. To this category belong stepped disk extruders [Westover, 1962 Raleigh, 1879], drum extruders, spiral extruders [Ingen Housz, 1975], diskpack extruder [Tadmor, 1979, 1980 Tadmor et al, 1979, 1983 Hold et al., 1979 Valsamis, 1983], and many others. 

Viscous drag extruders Drum extruder Diskpack extruder Stepped disk extruder... 

Another development in disk extruders is the diskpack extruder. Tadmor originated the idea of the diskpack machine, which is covered under several patents [31-33]. The development of the machine was undertaken by the Parrel Machinery Group of Emgart Corporation in cooperation with Tadmor [34-39]. The basic concept of the machine is shown in Fig. 2.17. 

One of the advantages of the diskpack is that mixing blocks and spreading dams can be incorporated into the machine as shown in Fig. 2.18(a). 

Comparison of conveying mechanism in diskpack and single screw extruder... 

Because of the more complex machine geometry, the cost per unit throughput of the diskpack is higher than for the conventional single screw extruder. Therefore, the diskpack does not compete directly with single screw extruders. 

Applications for the diskpack are specialty polymer processing operations, such as polymerization, post-reactor processing (devolatilization), continuous compounding, etc. As such, the diskpack competes mostly with twin screw extruders. Presently, twin screw extruders are usually the first choice when it comes to specialty polymer processing operations. 

Z. Tadmor et al, The Diskpack Plastics Processor, Parrel Publication, Jan. (1982)... 

Disk extruders. There are several types of screwless extruders. These machines employ a disk or a drum to plasticate, mix, and extrude. Most designs are based on viscous drag flow. They include Maxwell s elastic melt extruder, Westover s stepped disk and drum extruders, and Diskpack [39]. The Diskpack extruder has the capability of performing all the elementary steps of plastics processing by combination of differently shaped rotating... 

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