Edge sealing

Labyrinth seals are simple to manufacture and can be made from conventional materials. Early designs of labyrinth seals used knife-edge seals and relatively large chambers or pockets between the knives. These relatively long knives are easily sibject to damage. The modern, more functional, and more reliable labyrinth seals consist of sturdy, closely spaced lands. Some labyrinth seals are shown in Fig. 10-107. Figure 10-107 7 is the simplest form of the seal. Figure... 

Opposed-blade damper A damper iii which the adjacent blades rotate in opposite directions, so that the leading edges seal against each other and the trailing edges seal against each other. 

Cassettes use feed and permeate spacers with one set of precut holes for the feed/retentate and another, smaller set of holes for the permeate. The feed spacer has a raised-edge seal around the... 

Membrane banners are applied to the exterior of the foundation and also beneath the floor slab during construction. Materials used for the membrane barriers range from coextruded poly olefin to polyvinyl chloride to foil sheets with many other materials in between. All membrane barriers must have the edges sealed to prevent radon from migrating around the edges and back into the building. 

FIGURE 5.1 Schematics of edge sealing of planar cells (above) and external gas manifold seals (below) used for a simple cross-flow SOFC stack design. 

Fig. HI.2. Plastic welding practice, (a) Some typical welds. (b) Technique for feeding rod into weld. With the rod bent back into a 45° angle, it is easy to heat and the rod is forced into the seam. The torch should be fanned between the rod and the parts being welded, with somewhat greater concentration on the latter, (c) An edge seal accomplished on a hot plate.

In some applications, impulse sealers are being replaced by machines which employ a continuously heated knife. In such machines, the film is supported across a roller which is coated with a resilient material such as silicone rubber (to which molten polyethylene will not adhere) and the hot knife edge pressed on to it. A strong bead edge seal is obtained. 

Even silicone-based materials cannot fulfill all requirements in diverse applications. One property of silicone materials is their high gas and moisture permeability, which is disadvantageous in, e.g., edge sealing of insulation gls s, where a barrier for water and gas has to be provided. Hydrocarbon polymer-based materials like poly-isobutene possess these desirable properties. However, they lack the ready curability and adhesion of RTV silicone materials. Preferably the advantages of the hydrocarbon base polymer and the silane condensation reaction should be combined. 

The large dryer in Building 31 has part of the edge seal worn away allowing material to fall on the floor. Replacement or repair of this edge seal would stop this loss. 

Evaluate the gaskets and edge seal integrity on each machine before production begins, to minimize spills onto the floor. 

CVH engine 3.60 mm mat gap 4070 Series IV mat Saffil edge seal Improved flow pipe Mat Loss... 

Seals are used in an attempt to reduce direct gas impingement onto the support mat. They are used in a variety of designs. In some cases, the mat is cut a little shorter, and a seal is placed before the mat. The alternative is to wrap the seal around the edge of the mat, or to change the characteristics of the mat such that the mat edge seals the rest of the mat from gas impingement. 

Two parts were tested w th a new low shot ceramic fibre material, acting as an edge seal. This material comprises of loise ceramic fibres which can be compressed, but have the ability to revert to the original loose structure once the compressive force is removed. There is no vermiculite, the fibres have sufficient elasticity to revert to the original thickness, which is a lot greater than the mat gap thus p.-otecting the mat. 

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