Packings interlocking

Quartz, the commonest phase found in nature, ranges from huge crystals, to amorphous-looking powders a few microns in size, to shapeless masses of chalcedony agate or flint consisting of densely packed, interlocked microscopic crystals. The transformations between the three common forms and vitreous silica is as follows ... 

Figure 9-6QQ. Nutter Snap-Grid high-capacity grid packing with good structural integrity (interlocking) and reduced fouling. Used by permission of Nutter Engineering, Harsco Corp., Bull. CSG-2.

Figures 1,2, and 3 show stereoscopic views of their crystal packing. It is clearly seen that the exo-bicyclo [2.2.1] anhydride 1 has a hardly interlocked monolayer structure and so does the endo isomer 2 except for slight interpenetrations. These structural features facilitate molecular migrations upon chemical reaction, whereas the bicyclo[2.2.2] anhydride 3 exhibits strong interlocking, preventing molecular migrations.

Fig. 3 Stereoscopic representation of the molecular packing of eMdo-bicyclo[2.2.2]oct-5-ene-2,3-dicarboxyanhydride (3) on its (100) face showing interpenetrating strongly interlocked layers...

The mechanical effect of surface topography also exerts an influence on the interphase. The anodized oxides are the best examples of this feature. The oxides may be formed by a porous network 60 nm thick composed of pores close packed of 20 nm in diameter. The epoxy can penetrate into this structure to the bottom of the pores (Fig. 9). The effect is of a mechanical interlocking of the epoxy with the oxide which... 

To promote uniform distribution of vapor and liquid throughout the packed bed Uniform distribution improves packing efficiency. For instance, random packing particles that interlock" with, or "nest inside other particles can lead to channeling and therefore to lower efficiency. 

Jaeger Tri-Pack (Figs. 8.3b, 8.4c). This packing replaces the cylindrical shape of the Pall ring by a spherical shape. This provides more void space and better distribution of active surface than the Pall ring and minimizes interlocking (10). Jaeger Tri-Packs are available ia... 

A general problem in the use of monolith structures in reactor tubes is incomplete wall contact. Since individual tubes of multitubular reactors always have a diameter tolerance of ca. 1 mm and interlocking of the structure with the tube wall must be avoided, the bypass of flow at the wall is even greater than with random packings. Up to now there have been no publications of the magnitude and effects of this bypass. 

Saddle-shaped packings, such as Intalox saddles and Berl saddles, are available in sizes from j to 2 in. These packings are formed from chemical stoneware, plastics, or any other material that can be shaped by punch dies. They form an interlocking structure which gives less side thrust and more active surface area per unit volume than Raschig rings. 

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