Screw modular

The head of the femoral component then articulates with an ion-bombarded, HDPE, high walled, acetabular liner which fits iato a screwed ia, machined, titanium, chromium—cobalt—molybdenum or vanadium—aluminum metallic alloy hydroxyapatite-coated acetabular shell/cup. Each of the separate parts of the modular system for total hip arthroplasty is manufactured ia several different sizes. 

White, J. L., Kim, E. K., Keum, ]. M., and Jung, H. C., Modeling Heat Transfer in Screw Extrusion with Special Application to Modular Self-Wiping Co-Rotating Twin-Screw Extrusion, Polym. Eng. Set, 41, 1448 (2001)... 

Keum, J. and White, J. L., Heat Transfer Coefficients and Screw Temperature Profiles in Modular Twin Screw Extrusion Machines, SPE ANTEC Tech. Papers, 50,108 (2004)... 

The modular screw and barrel concept has additional advantages, since regions where high wear occurs can be economically replaced without changing... 

Modular screw design to assist in densiLcation, and distributive and dispersive mixing... 

S. Bawiskar and J. L. White, A Composite Model for Solid Conveying, Melting, Pressure and Fill Factor Profiles in Modular Co-rotating Twin Screw Extruders, Int. Polym. Proc., 12, 1331 (1997). 

C. G. Gogos, M. Esseghir, D. W. Yu, D. B. Todd and J. Curry, The Twin-screw Mixing Element Evaluator On-line Performance Evaluation of Modular Twin-screw Mixing Elements, SPE ANTEC Tech. Papers, 40, 270 (1994). 

Fig. 10.1 Photograph and schematic representation of the modular screw-element sequences and barrel sections of an intermeshing, co-rotating TSE. [Courtesy of Coperion Werner and Pfleiderer Corp.]...

Fig. 10.13 Melting of low density polyethylene (LDPE) (Equistar NA 204-000) in a starve-fed, fully intermeshing, counterrotating Leistritz LMS 30.34 at 200 rpm and 10 kg/h. (a) The screw element sequence used (h) schematic representation of the melting mechanism involving pellet compressive deformation in the calender gap (c) the carcass from screw-pulling experiments. [Reprinted by permission from S. Lim and J. L. White, Flow Mechanisms, Material Distribution and Phase Morphology Development in Modular Intermeshing counterrotating TSE, Int. Polym. Process., 9, 33 (1994).]...

Fig. 10.38 The examples of Leistritz melt conveying, modular CRNI screw elements studied by White and associates, (a) Thin flighted forward matched and staggered (b) thick-flighted, reverse matched and staggered. [Reprinted by permission from D. S. Bang, M. H. Hong, and J. L. White, Modular Tangential Counterrotating TSEs Determination of Screw Pumping Chararacteristics and Composite Machine Behaviour, Polym. Eng. Sci., 38 485 (1998).]...

S. Lim and J. L. White, Flow Mechanisms, Material Distribution and Phase Morphology Development in a Modular Intermeshing Counterrotating Twin Screw Extruder of Leistritz Design, Int. Polym. Process., 9, 33—45 (1994). 

Further patents describe the modular principle for different screw and kneading elements threaded and clamped to a core shaft. The benefits are striking ... 

These benefits resulted in the USP [21] with priority 1959 for R. Erdmenger. The modular design is illustrated in Fig. 2.14 below with a combination of different consecutive screw and kneading zones and in Fig. 2.15 as a modular assembly diagram. 

These three groups of patents, namely, the widely used threaded screws, the kneading elements, and the modular design principle paved the way for the development of a highly effective new machine type for process engineering and plastics technology. 

The clearance considerations above apply for constant screw geometry along the axis and particularly for a constant pitch. Modular screws with elements with different pitches create the following dilemma ... 

The modular technology was developed both for the internal screw geometry (Fig. 2.30) and for whole machines (Fig. 2.31). 

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

A pair of screw elements is conveying if the flat profiles are extended into the third dimension by helical rotation. In this case, we speak of screw elements. The pitch T of the element is another important dimension here. In today s modular screws, individual elements each have a constant pitch and a pitch variation is achieved by using different types of element. 

Generation 2 (from 1962) modular barrel and screw design, adjacent shafts... 

For a majority of applications, the modular design has been accepted for the twin screw extruder. This allows optimum adjustment of wear protection in the respective process zone and material selection for the corresponding process zones to ensure a maximum life span. 

The modular principle is also frequently used in the design of the extruder screw. The screw comprises individual screw elements, which are threaded onto a shaft. The elements are positively fitted to the shaft to transmit the required torque. They are also attached together and axially clamped. The elements of a screw module are typically made of nitrided steel. Special designs are required for wear protection and corrosion protection depending on the respective requirements ... 

The Alexanderwerk Inc. roller compactor (Fig. 18) is modular designed with a horizontal twin feed screw... 

---