A range of filter media can be used on drum filters, depending on the specific application. Most media have a cut-off point below which value particles pass through the filter. One way to achieve high filtration efficiencies at low particle sizes is to coat the filter medium with a fine powder – the precoat – to […]
The choice of the most suitable method of cake discharge for a particular RVDF application depends not only on the nature of the cake, but also on considerations of protection of the main filter medium from wear. The cake can vary in consistency, thickness and structure according to the products being handled, from a pastelike […]
The rotary vacuum drum filters described so far utilize a filtrate flow from outside the drum to the inside, where the vacuum is applied. Rotary drum filters also exist with filtrate flow from inside the drum. A simple version is little more than a rotating drum strainer, used to clarify raw water, as filters for […]
A rotary vacuum drum filter consists of a cloth-covered compartmental drum suspended on an axial shaft over a feed trough containing the suspension, with approximately 50 to 80% of the screen area immersed in the suspension. The trough will usually include an agitator to maintain the feed suspension at a constant concentration. The oscillating swing-type […]
The Nutsche, tipping pan and table filters are intended only for solids recovery from liquid suspensions. The rotary drum filter is mainly used for that purpose, but has some applications in clarification as well as solids recovery. Rotary drum filters may be vacuum driven (rotary drum vacuum filters) or pressurized (pressure drum filters). The former […]
The tipping (tilting) pan filter obviously, and the rotary table filter somewhat less obviously, are developments of the simple batch vacuum filter described in the previous chapter. The single tipping pan is a batch filter, just like the Nutsche, but other versions, including the table filter, are intended to allow more or less continuous operation. […]
The next group of equipment types to be covered in this Section are all vacuum driven, and nearly all are intended for solids recovery, rather than for decontamination purposes. The simplest vacuum filter is the laboratory Büchner funnel, and the simplest practical embodiment of that is the Nutsche filter, which is found widely distributed throughout […]
Gyratory screen separators, which impart a basically circular motion to the particles on the screen, are used for high capacity separation by size of dry materials, and for wet separations when oversize material constitutes a large percentage of the feed (a typical example is shown in Figure 3.13 ). Common practice with gyratory screens has […]
A huge volume of solids is processed by means of vibratory screens. These can be either horizontal or gently inclined, and they incorporate the use of vibratory motors to achieve the required motion of the screen. In order to get flow of the separating solids across a horizontal screen, the vibrating motors need to run […]
The simplest form of size classification is the hand-held test sieve, fitted with a piece of precise wire mesh, and used to classify a sample of solids into two ranges of particle size – above and below the aperture of the mesh. These are used in the dry and shaken carefully and sufficiently to achieve […]
