Filter continuous belt drum

One problem that can develop is that the filter becomes clogged because of fine particles from the sludge that are caught in the pores, precipitation that has occurred during the dewatering stage, or a thin nonporous layer that has formed on the surface. One way to counteract this clogging is to use a continuous-belt drum filter... 

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

Agitated/Monoplate Nutsche Filter/Dryer Horizontal Plate Filter/Dryer Continuous Equipment Rotary Drum Filter Centrifugal Filter Horizontal Belt Filter... 

Fig. 16-5). Here the filter medium is attached to a continuous belt instead of directly to the drum. The belt, after leaving the rotary drum, makes some abrupt changes in direction, which loosens and discharges the cake. The septum is then washed from both sides with water52 to remove any remaining material. This wash often is charged to the filter. 

Plate-and-frame filter presses are particularly suited to batch operations. Modern frames are made of polymers (mainly polypropylene), which have replaced wood as a building material. Large amounts of products, on the other hand, are filtered routinely via continuous-belt filters or rotary drum-type filters. Following the filtration step, inorganic salts are removed by washing with water. 

Representative commercial sizes of some types of pressure filters for operation in batch modes are reported in Table 11.11. Some of these data are quite old, and not all of the equipment is currently popular thus manufacturers should be consulted for the latest information. Commercially available size ranges of continuous belt, rotary drum, rotary disk, and horizontal rotary filters are listed in Table 11.12. For the most part these devices operate with vacua of 500 Torr or less. 

Horizontal or vertical vessel fillers, especially Ihose vv iih vertical rotating elements, have undergone rapid development w ith the aim ol making truly continuous pressure tillers, particularly hut not exclusively lor the filtration of line coai. There are basically three categories of continuous pressure litters available, i.e,. disk fillers, drum filters, and belt fillers including both hydraulic and compression varieties. 

The suspension of bicarbonate formed is removed from the bottom of the tower, filtered, and washed on a rotary drum filter. The cake is then centrifuged and dried on a continuous belt conveyor at 70°C. Bicarbonate made in this fashion is about 99.9% pure. 

In some drum filters, blinding of the medium can be amehorated by a continuous removal of the cloth during rotation, with back-washing. Again, this produces a loss of available filtration area on the drum. Figure 11.8 this effect is not present in horizontal belt filters. 

Reaction can be undertaken either in a series of wooden vessels or mild-steel tanks fitted with steam coils and agitators, and the reaction train is usually designed to give a total retention time of 4-6 hours. The slurry produced is filtered and the calcium carbonate cake washed and dewatered on continuous vacuum machines of the traveling-belt type, or alternatively, on a two-stage drum-filter installation provided with intermediate repulping. (In some earlier plants, plate-frame filter presses were installed for this purpose.) Final clarifica-... 

The two equipment simulation modules provide calculation sequences for more than 20 types of vacuum and pressure filters, potentially involving combinations of cake formation, compression, gas deliquoring and washing. Batch filters include single and multi-element leaf filters, filter presses and diaphragm and tube presses while continuous filters include the horizontal belt, drum, disc, table and tilting pan filters. The user is able to define filter... 

In Section 7.1 the principal features of common continuous filter cycles are described, while Section 7.2 presents the equations required to model these cycles. Section 7.3 provides detailed example calculations for the horizontal belt filter and the rotary drum filter as these are representative of typical continuous cycles. Section 7.4 shows how computer simulations can be used to examine in detail the effects of process variables on... 

In this section the horizontal belt filter and the rotary drum filter are chosen to illustrate the level of detail that can be achieved when the design equations and procedures outlined in Section 7.2 are used to size and predict the performance of continuous filters. 

Horizontal- or vertical-vessel filters with vertical rotating elements in particular have been under rapid development recently with the aim of making truly continuous pressure filters, particularly, but not exclusively, for the filtration of fine coal. There are basically three categories of continuous pressure filters presently available disc filters, drum filters and belt filters, the last category including both the hydraulic and compression varieties. For the purpose of this review, we shall also briefly consider some semi-continuous, indexing cloth filters and other types with intermittent movement of elements. Only those filters which discharge the solids in the... 

Multicompartment drum filters range in size from about 1 sq. metre to over 100 sq. metres they are widely used in mineral and chemical processing, in the pulp and paper industry, and in sewage and waste materials treatment. Despite their uneven wash distribution and frequently high run-off (as the filter surface is not horizontal), many continue to be used as cake washing filters. Effective washing of the filter cloth can be done only with the belt discharge type, where the cloth leaves the drum for a brief period and can thus be washed on both sides. 

As an alternative to the rotary filter drum, the filter may be stretched into a horizontal continuous belt, around two rotating drums, as shown in the diagram in Figure 12 of a Florentine filter from a Tirtiaux plant. Filtration takes place on the upper, horizontal surface of the belt, which has a vacuum chamber beneath it. In the diagram shown, the first portion of the filter belt, which in this case is perforated stainless steel, allows for any crystal fines to be recycled so they do not contaminate the olein fraction. 

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... 

Scale-Up on Rate Filtration rates calculated from bench-scale data shouldbe multiplied by a factor of 0.8 for all types of commercial units which do not employ continuous washing of the filter medium and on which there is a possibility of filter-medium bhnding. For those units which employ continuous filter-medium washing, belt-type drum and horizontal units, the scale-up fac tor maybe increased to 0.9. The use of this scale-up fac tor assumes the following ... 

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