Sintered stainless-steel

Rigid Porous Media These are available in sheets or plates and tubes. Materials used include sintered stainless steel and other metals, graphite, aluminum oxide, silica, porcelain, and some plastics—a gamut that allows a wide range of chemical and temperature resistance. Most applications are for clarification. 

Micrograph of sintered stainless steel fiber felt used as DL (reference bar indicates 100 pm). (Reprinted from J. Liu et al. Journal of Power Sources 133 (2004) 175-180. With permission from Elsevier.)... 

We note that the siren is acoustically coupled to the 8-inch internal diameter agglomerator chamber by an exponential type acoustic coupler. The 9.25 inch long tubular section has 16 - 0.5 inch diameter exhaust holes for the siren air. The acoustically transparent barrier prevents the cold siren air from flowing into the heater section. The sheet of felted, woven and sintered stainless steel has a low flow resistance rayls giving an acoustic transmission loss of only 4 dB. By automatically controlling the pressure drop across the barrier to about 1 inch of water, we are... 

Microfiltration membranes usually have a nominal pore diameter in the range of 0.1-10 pm. However, the membrane specification is not an absolute parameter. The membranes usually present a pore size distribution around the nominal value and the shape of the bioparticles can determine whether they are retained or pass through the membrane. The membranes are manufactured from polymers, such as Teflon, polyester, PVC (polyvinyl chloride), Nylon, polypropylene, polyethersulfone, and cellulose, or from inorganic materials, such as ceramic and sinterized stainless steel. 

Until now, bioreactors of various types have been developed. These include loop-fluidized bed [14], spin filter, continuously stirred turbine, hollow fiber, stirred tank, airlift, rotating drum, and photo bioreactors [1]. Bioreactor modifications include the substitution of a marine impeller in place of a flat-bladed turbine, and the use of a single, large, flat paddle or blade, and a newly designed membrane stirrer for bubble-free aeration [13, 15-18]. Kim et al. [19] developed a hybrid reactor with a cell-lift impeller and a sintered stainless steel sparger for Thalictrum rugosum cell cultures, and cell densities of up to 31 g L1 were obtained by perfusion without any problems with mixing or loss of cell viability the specific berberine productivity was comparable to that in shake flasks. Su and Humphrey [20] conducted a perfusion cultivation in a stirred tank bio-... 

These are housings of metal or plastic containing one or more replaceable and renewable cartridges which contain the active filter element, usually based on a polymeric filter medium or in some cases, sintered stainless steel. They are useful as polishing filters where the level of solids to be removed is relatively low, to prevent the filter from blocking up. 

Using a two-stage, single-pass module of food-grade dynamic metal oxide membrane on a sintered stainless steel support tube under a TMP of approximately 20 bars and a temperature of 50 C, Thomas et al. [1987] have successfully clarified apple puree with a juice yield of 86% and a steady state flux of about 85 L/hr-m. The quality of the clarified apple juice by this dynamic or formed-in-place membrane is excellent -sparkling looking and flavor retained. As much as 65% reduction in the total pectins has been attained. 

In this paragraph shortly the permeation measurement method is introduced, followed by various examples of permeation through a silicalite-1 membrane on a sintered stainless steel support. This includes unary and binary mixtures as a function of partial pressure, composition and temperature. Finally the present state of modelling permeation through silicalite-1 membranes is reviewed. 

The permeation examples that are given here are based on own work and have been published in different articles [61-66]. The membrane used is of the asymmetric type and consists of a 40 pm thick layer of intergrown silicalite-1 crystals on a 3 mm thick layer of highly porous sintered stainless steel. The geometric surface area amounts to 3 cm. Stainless steel has the advantage of easy mounting in all types of equipment which facilitates practical application compared to ceramic supports. 

Sintered porous-metal-powder filters Sintered, stainless steel, semi rigid fiber filters... 

Some more module configurations are reported for use in MD. Lawson and Lloyd [77] have designed a laboratory-scale MD module as shown in Figure 19.13, where the membrane was sandwiched between the two half-cells, and several hose clamps held the module together. The total area available is 9.7 cm and the smooth transitions at the module entrance as well as exit allow achievement of relatively high Reynolds numbers, whereby conventional boundary layer equations are applicable. The module does not require a support in low pressure-drop applications such as DCMD. Wider permeate channels would require a support for VMD experiments. A porous sintered stainless steel material has been used for the gas permeation experiments. 

Using light microscopy, Bird and Bartlett [170] observed that the deposit on sintered stainless steel MF membrane (2.0 pim) fouled with whey consists of a loose sheet-like protein-rich stmcmre which is removed during the first few minutes of chemical cleaning (Figure 22.11). Cleaning with sodium hydroxide removes the loose top proteinaceous layer, which results to the sharp... 

TTie TWR used is a double pipe reactor, about 0.95 m in length, with an outer pressure bearing tube made of stainless steel (1.4989, o.d. 140 mm, i.d. 80 mm) and in inner porous tube of sintered stainless steel (1.4404, o.d. 66 mm, i.d. 60 mm, average pore width 35 pm). 

A slipstream of the fuel gas is taken out and diverted to the sampling system by means of an Inconel probe equipped with a sintered stainless steel filter in the tip to remove particles. The probe is placed co-currently to the gas flow and is positioned at a bend in the flue gas duct, after the particle filtering system. Gas temperature at this point is expected to be about 700"C,... 

So far, essentially three different approaches have been reported for the preparation of zeolitic membranes [119]. Tsikoyiannis and Haag [120] reported the coating of a Teflon slab during a "regular" synthesis of ZSM-5 by a continuous uniform zeolite film. Permeability tests and catals ic experiments were carried out with such membranes after the mechanical separation of the coating from the Teflon surface [121]. Geus et al. [122] used porous, sintered stainless steel discs covered with a thin top layer of metal wool to crystallize continuous polycrystalline layers of ZSM-5. Macroporous ceramic clay-type supports were also applied [123]. 

If a thinner membrane is required, then one must choose a supported membrane. The permselective metal layer may be palladium or, more commonly, palladium-silver alloy, palladium-copper alloy, or other alloy of palladium. The permselective layer ranges in thickness from about 2-25 /an thinner than 2/rm is very difficult to achieve without introducing pin holes and other adverse defects into the permselective layer. The support layer is porous and is composed of either metal (such as sintered stainless steel or tightly woven wire cloth) or an inert ceramic alumina is very common. Since all of the mechanical strength is derived from the support layer, consideration must be given to its shape and thickness. 

The last failure mechanism involves defects in the underlying support layer that are transferred to the thin permselective layer. Examples include surface irregularities (such as pits or cracks), and particles on the support surface. Sintered stainless steel supports may be especially prone to residual particles of metal powder that can pierce the thin permselective metal layer during use. Shock and vibration may cause damage (such as cracking) to a ceramic support layer that then results in damage to, and failure of, the permselective layer. 

FIGURE 7 Stainless steel sample cells (5-mL), or bombs, showing screw cap ends and sintered stainless steel frits. 

Sintered stainless steel or stainless steel mesh filters are useful in highly contaminated gas streams as they can be cleaned and reused. These filters I can be had for 1,10, 25, and 100 micron efficiencies. 

In cross-flow flltration, the wastewater flows under pressure at a fairly high velocity tangentially or across the filter medium. A thin layer of solids form on the surface of the medium, but the high liquid velocity keeps the layer from building up. At the same time, the liquid permeates the membrane producing a clear filtrate. Filter media may be ceramic, metal (e.g., sintered stainless steel or porous alumina), or a polymer membrane (cellulose acetate, polyamide, and polyacrylonitrile) with pores small enough to exclude most suspended particles. Examples of cross filtration are microfiltration with pore sizes ranging from 0.1 to 5 pm and ultrafiltration with pore sizes from 1 pm down to about 0,001 pm. 

Membrane Testing. The membranes were characterized on an RO test loop. Hollow-fiber modules were equipped with fittings as shown in Figure 4 to allow circulation on both sides of the membrane. Flat-sheet membranes were tested in special cells of the type shown in Figure 5 recirculation solution could be pumped into a port in the center of the cell and forced to flow through a sintered stainless steel support plate to reach the permeate side of the membrane. 

Solvent Line Filter (Sinker) The solvent line sinker, typically a 10-pm sintered stainless-steel filter, can be replaced by direct connection to the Teflon solvent line (Figure 10.2a). The sinkers should be replaced annually. A partially plugged solvent sinker can restrict solvent flow, which can result in poor retention time precision. 

The concept of producing clarified fruit juice by a single pass of enzyme-treated fruit puree through a tubular, metallic ultrafiltration membrane system was recently described by Thomas et al. (5, 6). The process is known commercially as the Ultrapress process, since pressing and ultrafiltration are accomplished simultaneously (7). The metallic membrane ultrafiltration system is composed of sintered stainless steel tubes of varying diameters with membranes formed-in-place within the porous matrix of the tubes by deposition of various metallic oxides. Metallic oxides in combination with polymers are also possible. 

Figure 19-10 shows a solvent filter arrangement. The fdter, made from sintered stainless steel or titanium, is placed in the solvent reservoir, and ultrapure helium is passed through it at about 5-10 psi. Under such conditions, a cylinder of helium will last about 5 months in continuous operation. 

The cleaned solvent is collected in a 20-m tank and, via sintered stainless steel filters, transferred to a larger storage tank for reuse. As the metal filters may become very radioactive, provision is made for back washing and remote replacement. Final solvent polishing by adsorption on anion-exchange resin has been found advantageous at Hanford [S4]. 

In the spray calciner, liquid waste is pumped to a nozzle at the top of the calciner where it is atomized by pressurized air, producing droplets with diameters less than 70 irni that are dried and calcined in-fli t in the 700 C-wall-temperature spray chamber. Sintered stainless steel dust filters collect a portion of the powder with a mean diameter of 10 fjm. They are periodically cleaned by a reverse pulse of air. Calcine from the spray chambers and filters drops directly into the melting canister. Frit is fed to the cone of the calciner. 

Filters remove dust particles and other mechanical impurities from the eluents and solutions of samples. Filters made of sintered glass, porous polymers, and sometimes also of sintered stainless steel are used for aqueous mobile phases. 

A 1/8-in. thick sintered stainless steel plate serves as the gas distributor. Preheated inlet gas enters a plenum chamber and then passes through the distributor. Offgases pass through a cyclone for fines removal and then to a knockout pot for heavy tar condensation. After the gas is... 

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