Rotary vacuum drum

One of the oldest filters applied throughout the chemical processing industry is the rotary vacuum drum filter, which is illustrated in Figure 8. This machine belongs to the group of bottom feed configurations. Rotary drum filters are typically operated in the countercurrent mode of operation. The principle advantage of these machines is the continuity of their operation. 

Rotary Vacuum Drum Filters Designed By M/s. Eimco, USA... 

Vacuum filters include the nulschc filter, enclosed agitated vacuum fillers, the vacuum leaf filter, the tipping pan filter, horizontal rotating pan filters, horizontal belt vacuum fillers, rotary vacuum drum lilters. and rotary vacuum disk filters. 

Whole-broth clarification Rotary vacuum drum filtration Centrifugation Crossflow MF, UF Maintains high throughput Does not require filter aids... 

Filtration is a unit operation commonly employed nowadays in biotechnological processes. In this unit operation, a filter medium acts as a physical barrier to particles larger than its pores. Traditional filtration devices such as filter presses and rotary vacuum drum filters have so far found no application for the separation of animal cells. Nevertheless, membrane filters are commonly employed, as well as some alternative filter designs such as spin-filters. In the next sections, the most common types of filters used for animal cell separation will be discussed. 

The filter press is to be replaced by a rotary vacuum-drum filter with negligible filter-medium resistance. This rotary filter can deliver the filtrate at a rate of 1000 lb/h when the drum speed is 0.3 r/min. Assuming the fraction submerged and the pressure drop are unchanged, what drum speed in r/min is necessary to make the amount of filtrate delivered in 24 h from the rotary filter exactly equal to the maximum amount of filtrate obtainable per 24 h from the plate-and-frame filter ... 

FIGURE 14.9 Rotary vacuum drum filter (Example 14.6). 

Cross-sectional end view of rotary vacuum-drum filter. (Eimco Corporation.)... 

I-0.0587(ln 4) lO[Pg.667]

Filtration can include filter presses, rotary vacuum drum filters, and variations on synthetic membrane... 

Precoated rotary vacuum drum filters (Fig. 6) are used by filtering a slurry of filter aid and water first, then subsequent product filtration. Difficult filtering materials, which have a tendency to blind, are removed with a doctor blade. Precoat is removed along with the slurry to expose a new filtration surface each cycle. 

Several of the eontinuous filtration units discussed below may be operated in pressure and vacuum conditions thus the continuous rotary vacuum drum, disc or hnmimtsjl belt filter can be enclosed in a pressure v seL Separation may then ensue by use of a gas pressure blanket in the vessdL This technique is oflen used in solvent fihrations. Some processes m the simultaaeous use of pressure upstream, with vacuum downstream of tire filter in this maimer, the continuous filtration characteristic can be coiqiled with fairer filtration dif ential pressures. 

Figure 11.4 Rotary vacuum drum filter (Courtesy of Filtration Services Lt4 Macclesfield, U.K.)...

Theory vs Practice Rotary Vacuum Drum Filter... 

EXAMPLE 14.2-4. Filtration in a Continuous Rotary Drum Filter A rotary vacuum drum filter having a 33% submergence of the drum in the slurry is to be used to filter a CaCO slurry as given in Example 14.2-1 using a pressure drop of 67.0 kPa. The solids concentration in the slurry is = 0.191 kg solid/kg slurry and the filter cake is such that the kg wet cake/kg dry cake = m — 2.0. The density and viscosity of the filtrate can be assumed as that of water at 298.2 K. Calculate the filter area needed to filter 0.778 kg slurry/s. The filter cycle time is 250 s. The specific cake resistance can be represented by a = (4.37 x 10 ) (—Ap) , where —Ap is in Pa and a in m/kg. 

Figure 1.26 Representations of rotary vacuum drum filters, (a) bottom fed, knife/scraper discharge (Filtration Services) (b) bottom fed, roller discharge (c) bottom fed, string discharge (d) bottom fed, belt discharge (Dorr-Oliver Eimco) (e) top fed (Filtration Services) (f) internal drum.

The precoat drum shown schematically in Figure 1.43 is similar in basic form and operation to the bottom fed rotary vacuum drum filter (see Section 1.4.1.5). Prior to filtration of the feed, a suspension of precoat is filtered under vacuum onto the drum surface to a depth between 4 and 15 cm. The feed is then introduced and filtration proceeds to produce thin, sometimes... 

Mud sweetening Rotary vacuum drum filter 7, 11 Good mechanical resistance... 

Red mud underflow Rotary vacuum drum filter 13 Amorphous/coarse 5, 9, 14 Resistance to blinding and... 

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