Sintered wire mesh

FIGURE 45.7 Scanning electron micrographs of four different types of porous structures (a) plasma sprayed coating (7x), (b) sintered wire mesh coating (7x), (c) sintered beads coating (20 x), and (d) Hedrocell porous tantalum (50x). 

These replaceable cartridges or packs are the most commonly used however, there are cartridges of wire mesh, sintered or porous metal which can be removed, cleaned, and replaced. Usually, the fine pores of the metal become progressively plugged and the cartridges lose capacity. They are often used for filtering hot fluids, or polymers with suspended particles, pharmaceuticals, and foods (liquids). In the case of polymers and other applications a special solvent and blow-back cleaning system may be employed. 

Most analyzer sampling systems require a filter with at least one wire mesh strainer (100 mesh or finer) to remove larger particles that might cause plugging. Available filter materials include cellulose, which should only be considered if it does not absorb the components of interest. Sintered metallic filters can remove particles as fine as 2 ym, cellulose filters can remove down to 3 /on, and ceramic or porous metallic elements can trap particles of 13 ym or larger. When the solids content is high, two filters can be installed in parallel with isolation valves on each. Motorized self-cleaning filters are also available for such services. 

Experimental samples of the fiat miniature heat pipe were chosen as copper /water heat pipe with three types of a wick sintered powder wick, wire mesh wick and wire bundle wick (Figure 10). The experimental data of qmax, Qmax, Rhp, he and he as a function of heat pipe tilt were obtained for different heat load and heat pipe orientation in space and temperature level. 

Theoretical simulation of mHPs with different wick structures (sintered powder, mesh structure, wire bundle) is an efficient tool to perform the comparisons of mHP efficiency. Experimental verification of mHP parameters proves validity of the simulation software. 

It is often found that the sintered metal and porous ceramic supports that have been used for many academic membrane studies are very expensive, sometimes even exceeding the cost of the palladium alloy membrane by several fold. This situation cannot be accepted for commercial membrane modules, especially when a large membrane area of up to several hundred to several thousand square meters is required. Some of the least expensive membrane supports include tension springs for tubular membranes and woven wire mesh for planar membranes, but even these supports can be costly, and further development of exceptionally low cost membrane supports is needed. 

The third alternative is a filter design that attempts to combine the advantages of frits with the advantages of the woven screens. The solution is a hybrid of woven screen and pressed-powder frit metal powder is pressed and sintered into a loose wire mesh. These filters are as thin as woven screens, but have a significantly larger open area and therefore a larger filtering capacity than woven screens. 

CONTAMINANT METAL FIBERS WIRE MESH sintered POWDER... 

Continuous layer filtration involves filtering the sugar syrup through a layer of activated carbon. Several types of filters are used, such as pressure leaf filters with metal frames on which a filter cloth that may be cotton, polyamide, or wire mesh is fixed rotary leaf filters or bed filters in which the filtering medium is a ceramic or sintered plate, wire mesh, or finely perforated metal plate. The latter filters are usually coated with a layer of filter aid that may be a diatomaceous earth. A suspension of active carbon in water or liquor is passed through the filter until a uniform layer of active carbon bed 10 to 15 mm thick builds up. The filter is then ready for filtration of the liquor that must flow to the filter at a uniform rate to avoid breaking the layer. 

There are three important types of metallic filter medium wire mesh, sintered powder, and random fiber. Wire mesh comes in a square weave or Dutch twill (woven in parallel diagonal lines). The different filter media do not perform equally with respect to their ability to hold contaminant, capture gels, etc. [11, 12]. A relative performance comparison is shown in Table 3.7. 

Wire mesh, square weave Wire mesh, Dutch twill Sintered powder Random metal fiber... 

Wire mesh square weave Wire mesh Dutch twill Sintered metal powder Random metal fibers... 

Metal wire mesh, e.g., of platinum, or sintered metal may also be used as an electrode material. A membrane surface that is soft due to a pretreatment may be suitable. Combiiung it with graphite felt assures an optimal contact by pressing them together. For example, titanium wire mesh or also porous sintered titanium metal coated with lead dioxide was used as an anode and graphite felt as a cathode for the previously mentioned reaction of y-butyrolactone [4]. 

Printability With 230 stainless steel wire mesh and emulsion thickness of 7.5 pm Sintered thickness 28-38 pm 200 pm traces on 400 pm pitch... 

Figure 9.27 Microporous tube-in-tube microreactor, (a) The photo of MTMCR, (b) microporous section SEM images of the front (c) and cross (d) sections of sintering metai wire mesh [102].

Filtration is accomplished with wire mesh screens (square or twill weave), sintered powder, or sintered metal fibers. Table 12.5 shows a comparison of the various filtration media and their characteristics. Square weave screen. Fig. 12.50, has every other wire... 

The crimping of the individual wires in a mesh goes a Itmg way towaids aisuring the stability of the mesh, and therefore the constancy of the apertures of the mesh, if the mesh is subject to movement or vibration in use. Where absolute stability is required, this can be achieved by sintering the mesh, so that the wires fuse together at their contact points. 

Metallic membranes are usually formed on a substrate of woven wire mesh, onto which the membrane is laid, either as a sintered layer of line metal powder, or, in fact, as a metal oxide (and thus, technically being a ceramic manbrane). Membranes made from stainless steel and aluminium are in industrial use. Pore sizes of these membranes can be from 2 am up to 100 pm. 

The metal cartridges described above are based on metal powders, but it should be noted that sintered metal cartridges are also available made from metal fibre and wire mesh. Both materials are sintered to give the necessary integrity of the medium (and, in the case of wire mesh, to maintain the precision of the apertures formed in the mesh when it was woven). Wire mesh elements are usually pleated and used for the thin media tasks described earlier, while sintered mesh cartridges operate by... 

Such vacuum filter dryers are used for processing pharmaceuticals, fine chemicals and toxic products, and can use a variety of filter media including sintered metal plates, woven wire mesh and a wide range of fabric cloths. Most processing steps can be carried out either under vacuum, or an inert gas such as nitrogen, or under normal atmospheric conditions. Dissolved solids can then be crystallized by application of cooling in the jacket. 

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