Filter medium definition

When a flocculated feed is added to a filter tank, there is a definite time lag before this material reaches the surface of the filter medium. Since this lag time is not known at the time of testing, a lag time of 8 to 10 minutes should be allowed before starting the first leaf test on a flocculated shiny. Two, or perhaps three, tests can be run before the elapsed time exceeds the probable retention time in the full-scale filter tank. With knowledge of the elapsed time after flocculation and data relating to the rate of degradation, the rates obtained on the leaf test runs can be adjusted to some constant lag time consistent with the anticipated full-sc e design. 

C (250° F) on a filtering medium. The sampling apparatus, however, may have to be modified to conform with the states definition of a particulate. For example, a state may define pai ticulate as any material collectible at stack conditions, a definition that would allow the filtering medium to be located in the stack. 

The permeability relative to a pure liquid, usually water, may be determined with the help of different devices that operate on the principle of measurement of filtrate volume obtained over a definite time interval at known pressure drop and filtration area. The permeability is usually expressed in terms of the hydraulic resistance of the filter medium. This value is found from ... 

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. 

After a precipitate has been filtered and washed, it must be brought to a constant composition before it can be weighed. The further treatment will depend both upon the nature of the precipitate and upon that of the filtering medium this treatment consists in drying or igniting the precipitate. Which of the latter two terms is employed depends upon the temperature at which the precipitate is heated. There is, however, no definite temperature below or above which the... 

When a flocculated feed is added to a filter tank, there is a definite time lag before this material reaches the surface of the filter medium. 

Definition Hard jet-black coal with high carbon content and calorific value Properties Bulk dens. 0.80-0.93 kg/l Uses Filler for NR, SR, adhesives domestic fuel filter medium in water treatment Trade Name Synonyms Carb-O-Fil [Shamokin Filler]... 

Pressure drop of fluid through filter cake. Figure 14.2-6 is a section through a filter cake and filter medium at a definite time t s from the start of the flow of filtrate. At this time the thickness of the cake is L m (ft). The filter cross-sectional area is A m (ft ), and the linear velocity of the filtrate in the L direction is v m/s (ft/s) based on the filter area of A m. ... 

As we have seen in Section 6.3.1.4 on the removal of particles from air by a fibrous bed via the mechanism of inertial deposition, if one can locate the limiting trajectory (dimension b in Figure 6.3.9A), the particle capture efficiency can be determined (e.g. definition (6.3.42a)). Determination of the limiting trajectory is achieved via particle trajectory analysis in the porous medium, i.e. the granular filter medium. The governing equation for particle motion in the inter-particle space is equation (6.2.45) ... 

The Elsevier Handbook of Filter Media has a precise definition of a filter medium ... 

The selection of a filter must begin with a definition of the job that the filter is required to do - at how fine a particle size is the separation to be made (cut-off point) and how sharp does this cut-off have to be, which will usually define the nature of the filter medium, followed by how much fluid is to be treated with what maximum pressure drop, which will define how much filter medium is required. The decision at this stage is then often between a depth filtration medium and a surface/cake filtering material. 

The retentivity relative to solid particles (e.g., spherical particles of polystyrene of definite size) is found from experiments determining the amount of these particles in the suspension to be filtered before and after the filter media. The retentivity K is determined as follows where g, g" =amounts of solid particles in liquid sample before and after the medium, respectively. 

By definition, a HEPA filter is a throw-away, extended-medium, dry-type filter having the following characteristics ... 

Medium Pressure Lamp.—A lamp filled with mercury vapor and operated at a pressure of about 1 atmosphere. The total intensity in the near ultraviolet and visible is lower than that of high pressure lamps, but photochemically useful light at wavelengths less than 3000 A. is produced. The ultraviolet spectrum consists of reasonably narrow lines with only a weak continuum. Hence, in conjunction with a filter or monochromator it is a good source for monochromatic radiation including reversed 2537-A. radiation (see definition below). 

For studies of the atmospheric aerosol, the particles are collected on filters or impactor plates. Although the original definition refers to particles and carrier medium taken together, it is now customary to apply the term aerosol more broadly and to include also deposits of particulate matter. We thus speak of aerosol samples, aerosol mass, etc., a usage... 

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