Continuous vacuum drum filter

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. 

Figure 16-5 A continuous belt drum filter. This works on the same principal as the vacuum drum filter. 

One of several problems that confront the procedure, for example, is the design of a suitable filter. Possibly vacuum drum filters could be used for liquids of low viscosity, but high-viscosity liquors will require new designs provided with ways and means for continuous displacement of the carbon cake from the filter leaf. 

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. 

Effect of Filter Medium Resistance on Continuous Rotary-Drum Filter. Repeat Example 14.2-4 for the continuous rotary-drum vacuum filter but do not neglect the constant R , which is the filter medium resistance to flow. 

The principle of continuous vacuum filtration on a curved convex surface, with filtration in the opposite direction to the force of gravity is applied in the most common type of filter, the vacuum drum filters. 

Working Method of a Continuous Operating Vacuum Drum Filter... 

The press belt drum filter [16] may be defined as a combination of a vacuum drum filter and a pressure stage. It comprises all the standard components of a traditional vacuum drum filter and a press belt attachment mounted on top. The standard components are of reinforced construction to withstand the additional stress imposed by the press belt equipment (up to 251 for a 45-m filter). This continuously operating special filter achieves a medium-specific reduction of the... 

Rotary vacuum drum and vacuum belt filters are extensively used on many process filtration operations, to provide filtration, clarification, dewatering or concentration. Moulded thermoplastic vacuum drum filters are particularly suited to providing continuous... 

Rotary Drum Filters The rotaiy drum filter is the most widely used of the continuous filters. There are many design variations, including operation as either a pressure filter or a vacuum filter. The major difference between designs is in the technique for cake discharge, to be discussed later. All the alternatives are characterized by a horizontal-axis drum covered on the cylindrical portion by filter medium over a grid support structure to allow drainage to manifolds. Basic materials of construc tion may be metals or plastics. Sizes (in terms of filter areas) range from 0.37 to 186 m (4 to 2000 ft ). 

Continuous vacuum filters are mostly of the constant pressure type and are mainly used in dewatering concentrated slurries such as concentrates. These filters are classified into disk, drum, and horizontal filters. The drum and the disk filters are the mainstay for most final detwatering, the drum filters being used to a lesser extent than the disk filters. These two groups of filters remove most fine particles from a process stream. 

Filter application Continuous vacuum filters Multicompartment drum Single compartment drum Top feed drum Scroll discharge drum Tilting pan Belt Disc... 

Filtration separates components according to their size. Efficiency depends on the shape and compressibility of the particles, the viscosity of the liquid phase and the driving force, which is the pressure created by overpressure or by vacuum. Filtration can be performed either as dead-end filtration, where the feed stream flows perpendicular to the filter surface (Lee, 1989) or as tangential flow filtration, where the feed stream flows parallel to the filter and the filtrate diffuses across it. Examples of the former are the continuous rotaiy vacuum dram filter, where a rotaiy vacuum filter has a filter medium covering the surface of a rotating drum and the filtrate is drawn through the dram by an... 

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