Liquid filtration

The characteristics of the pump relate the applied pressure on the cake to the flowrate at the exit face of the filter medium. The cake resistance determines the pressure drop. During filtration, liquid flows through the porous filter cake in the direction of decreasing hydraulic pressure gradient. The porosity (e) is at a minimum at the point of contact between the cake and filter plate (i.e., where x = 0) and at a maximum at the cake surface (x = L) where sludge enters. A schematic definition of this system is illustrated in Figure 2. 

This separation method is based on the molecular size of analytes. Analytes pass through porous stationary phase materials having different pore sizes, and molecular interactions between analytes and the stationary phase surface must be eliminated. A very strong solvent is therefore required in this system. This system is also called gel filtration liquid chromatography, gel-permeation liquid chromatography, or molecular sieve chromatography. This system is used to... 

Hayward, M. J., Hargiss, L. O., Munson, J. L., Mandiyan, S. P. and Wennogle, L. P., Validation of Solubility Measurements Using Ultra-Filtration Liquid Chromatography Mass Spectrometry (UP-LC/MS), American Society for Mass Spectrometry 2000 Conference Abstract, Long Beach, CA, USA, 2000. 

Parameter Dialysis Ultrafiltration SEC Precipitation/Filtration Liquid Phase-Separation... 

The mam characteristic properties of asbestos fibers that can be exploited in industrial applications arc their thermal, electrical, and sound insulation nonflammability matrix leinfoicement (cement, plastic, and resins) adsorption capacity (filtration, liquid sterilization) wear and friction properties (friction materials) and chemical inertia (except in acids). These properties have led to several main classes of industrial products or applications fire protection and heat or sound insulation,... 

Filter the product. Collect the filtrate into a 250 ml beaker. (Note The filtrate can be discarded down a sink drain.) Save the residue and discard the filtrate (liquid). 

All sol-gel derived catalysts were stable under reaction conditions, except the rhodium and iridium catalysts, whose colour changed significantly during reaction. The catalysts could easily be separated from the reaction mixture by simple filtration. The filtrated liquid product, that flew out colourless, exhibited no further catalytic activity. GC analysis of the liquid phase indicated the production of dmf with 100% selectivity in all cases, except for the platinum containing catalyst (Table 1). 

In fact Lp contains information about the porous strucmre (porosity, pore size, and tortuosity) of the membrane as well as the viscosity of the filtrated liquid varying nonlinearly with the temperamre. For the sake of comparison between membranes exhibiting different thicknesses, the membrane thickness Ax can be introduced in the permeability coefficient whose dimension becomes (m m/m Pa s). 

Fevy, R.V. The effect of pH, viscosity, and additives on the bacterial retention of membrane filters challenged with pseudomonas diminuta. In Fluid Filtration Liquid American Society for Testing and Materials (ASTM) Washington, DC, 1987 Vol. II. 

As shown in Figure 1, the filtrate (liquid) passes through porous media of two types the consolidated layer (the cast) and the porous mold. The flow of liquid through a porous medium is described by Darcy s law which, in one dimension, can be written... 

Crumble and pulverize the dried mycelial material and combine each 100 mg of this material with 10 ml of methanol. Place the flask in a hot water bath for four hours. Filter the liquids with suction through a filter paper in a buchner funnel with Celite to prevent clogging. Collect and save the filtrate liquids. Heat the slurry (the mush in the filter paper) two more times in methanol as before, filter, and accumulate the liquids of the three extractions. To be certain that all of the alkaloids have been extracted do a small extraction with a portion of the used slurry and test with Keller s reagent (glacial acetic acid, ferrous chloride, and concentrated sulfuric acid). If there is a violet indication, alkaloids are still present and further extraction is in order. 

To study filtration permeability, the compositions of SPC samples were accepted in accordance with the optimal composition given in Table 3.5. Water was used as a filtration liquid because it did not influence consolidation of the concrete. This allowed determinations about the presence or absence of filtering defects in investigated compositions and estimation of the influence of additives on filtration permeability. For SPC compositions tested with water, a filtration of acids is absent, as the effect of consolidation of the material in this case is shown. 

A bomb lesi consists of a 6-23 cm1 leaf covered with appropriate filler medium and placed in a smell pressure vessel containing enough sluny to form a desired amount of cake on die leaf. The quantity of filtrate liquid flowing through die cake is measured as a function of time under various pressures and ihe depth of cake formed is observed. This type of lest can provide infomiation for sizing pressure leaf filters or plate and frame fillers. These tests are best conducted by fiber vendors who have experience in translating the results to full-scale equipment. 

The pressure differential between the high- and low-pressure sides of the filter (the transmembrane pressure) is controlled by the control valve on the filtrate liquid leaving the filter. 

Parameter Dialysis Ultra- filtration SEC Precipitation/ filtration Liquid-phase separation... 

Johnson, P., 1986, Fluid Filtration Liquids Vplume II, ASTM Spedal Technical Publication 975, Publication Code 04-975002-39, p 59. 

Plate-and-frame filter presses. One of the important types of filters is the plate-and-frame filter press, which is shown diagrammatically in Fig. 14.2-3a. These filters consist of plates and frames assembled alternatively with a filter cloth over each side of the plates. The plates have channels cut in them so that clear filtrate liquid can drain down along each plate. The feed slurry is pumped into the press and flows through the duct into each of the open frames so that slurry fills the frames. The filtrate flows through the filter cloth and the solids build up as a cake on the frame side of the cloth. The filtrate flows between the filter cloth and the face of the plate through the channels to the outlet. 

The effects of compression on a filter cake or suspension can be measured using a piston press as illustrated in Figure 4.10. The press comprises an upright cylinder mounted on a base plate, where both the cylinder and plate are usually made from stainless steel. The base of the plate is recessed to accommodate a loosely fitting sinter drainage plate which is used to support the planar filter medium. The drainage plate must be sufficiently permeable to allow unrestricted passage of the filtrate. Liquid is forced from the cyhnder by a piston which is actuated either hydraulically or pneumatically. In more sophisticated units a force transducer can be mounted in the piston shaft to measure... 

With t , F and W known, the volume of washings VJ, and hence the total volume filtrate/liquid volume, and wash liquor flow rate are given by... 

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