Manifold fabrication

The cell head is fabricated from a 2.54-cm steel plate and has separate compartments for fluorine and hydrogen. The oudet-gas manifolds, hydrogen fluoride feed and purge lines, and electrical connections are on top of the head. The gas separation skirt is made of Monel. An insulating gasket maintains the seal between the tank and the head. The anode assembly consists of 32 carbon blades bolted onto a copper bar, each of which contains three copper conductor posts. The cathode assembly consists of three vertical, 0.6-cm parallel steep plates. The plates surround the anode assembly and are supported by three steel posts which also serve as conductors. 

While the manifolds were fabricated by a plain molding process, the microchannels substrate fabrication was quite complicated and was achieved by a multistage process. The following main stages were used in the process (1) double side oxidation of a 525 pm (1 0 0) silicon substrate to 1,000 A, (2) single side 1,200 A silicon nitride deposition, (3) silicon nitride channels template opening by reactive... 

Once the micro-channels were fabricated, the manifold were bonded to the substrate by epoxy glue, and the resistor was wired by a silver-based epoxy electric conductor and painted with a 1 pm thin paint to increase the surface emissivity. The triangular micro-channels and the unpainted resistor are shown in Fig. 9.12. 

FIG. 17-60 Reverse-pulse fabric filter (a) filter cylinders (b) wire retainers (c) collars id.) tube sheet (e) venturi nozzle (/) nozzle or orifice (g) solenoid valve (h) timer (j) air manifold (k) collector bousing (l) inlet (m) hopper (n) air lock in) upper plenum. (Mikmpul Division, U.S. Filter Corp. )... 

Each type of pressure leaf filter features a pressure vessel in which are located one or more filter elements or leaves of circular or rectangular construction. The filter media may be in the form of a synthetic fibre or other fabrics, or metallic mesh. Supports and intermediate drainage members are in coarse mesh with all components held together by edge binding. Leaf outlets are connected individually to an outlet manifold which passes through the wall of the pressure vessel. 

We thank P. Bowen for initial fabrication of the water manifolds in the system. Most of the fabrication of the equipment was done by R. Flores who also performed some of the initial flow tests on the peristaltic pumps. J. Bushman and M. Edwards modified and maintained the equipment W. Beiriger performed the x-ray diffraction analyses C. Slettevold and A. Biermann performed the particle analysis and determined the surface area on the samples. J. Wittmayer took the SEM photos. We also thank L, Gazlay and D. Hosmer for the gamma-ray spectroscopy analysis,... 

For many applications, like chemical-vapor-deposition reactors, the semi-infinite outer flow is not an appropriate model. Reactors are often designed so that the incoming flow issues through a physical manifold that is parallel to the stagnation surface and separated by a fixed distance. Typically the manifolds (also called showerheads) are designed so that the axial velocity u is uniform, that is, independent of the radial position. Moreover, since the manifold is a solid material, the radial velocity at the manifold face is zero, due to the no-slip condition. One way to fabricate a showerhead manifold is to drill many small holes in a plate, thus causing a large pressure drop across the manifold relative to the pressure variations in the plenum upstream of the manifold and the reactor downstream of the manifold. A porous metal or ceramic plate would provide another way to fabricate the manifold. 

The apparatus consists of a simple vacuum manifold similar to that shown in Fig. 4. The vacuum manifold should be fabricated from nickel or Monel metal, with silver-soldered or Swagelok connections. Valves should be of Monel metal, and the traps and scrubber, the function of which is to remove hydrogen fluoride vapor from the C103 F product, may be constructed conveniently of poly(chlorotrifluoroethylene) (Kel-F) tubing. A nickel cylinder of 500-ml. or 1-1. capacity serves as a reaction vessel, and a 500-ml. Monel bulb or similar vessel may be used as a product receiver. The scrubber (about 1-in. o.d.) is charged with pellets of sodium fluoride prepared in a separate operation by heating sodium... 

Figure 8.4 displays the air finfan unit cost in carbon steel materials. This figure includes the cost of the tube bundle, fan, fan electric motor, bundle casing, inlet/outlet casing manifolds, steel structure, stairways, and ladders. Tube pressure rating, material, and labor for both fabrication shop and field assembly are added factors per the associated tables. (See Tables 8.13 to 8.16.)... 

Even with their impressive physical changes, electrorheological materials have not solved the microactuator problem. This is due to the complex fabrication schemes required to incorporate these materials into microfluidic manifolds. Therefore,... 

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