Pressure filters horizontal belt

Horizontal or vertical vessel filters, especially those with vertical rotating elements, have undergone rapid development 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 available, ie, disk filters, dmm filters, and belt filters including both hydrauHc and compression varieties. 

A horizontal belt filter has been used in place of the small dmm filter in filtration studies (17). The entire filter was placed in a large pressure vessel with no moving parts passing through the filter shell. There is no commercial filter based on this principle the utilization of the space inside the pressure vessel would be poor and the filtration areas limited. 

The Flat-bed pressure filter (Hydromation Engineering Co. Ltd.) (19) is based on the above principle. The pressure compartment consists of two halves, top and bottom. The bottom half is stationary while the top half can be raised to allow the belt and the cake to pass out of the compartment, and can be lowered onto the belt during the filtration and dewatering stage. The filter can be considered as a horizontal filter press with an indexing cloth in comparison with a conventional filter press, however, this filter allows only the lower face of the chamber to be used for filtration. 

The vertical recessed plate automatic press, shown schematically in Figure 15 and described previously, is another example of a horizontal belt pressure filter. Cycle times ate short, typically between 10 and 30 minutes, and the operation is fully automated. The maximum cake thickness is about 35 mm washing and dewatering (by air displacement) of cakes is possible. Apphcations include treatment of mineral slurries, sugar, sewage sludge, and fillers like talc, clay, and whiting. 

Horizontal belt pressure filters, 11 379 Horizontal belt vacuum filter, 11 354-355 Horizontal box heaters, 19 511 Horizontal current classifiers, 16 619 Horizontal Feret s Diameter (HFD), 16 147 Horizontal injection wells, 16 613 Horizontal leaf filters, 11 366-367 Horizontal magnetic field-type (HMC), 23 857... 

Pressure filters, 76 658-659 horizontal belt, 77 379 thickening, 77 382-388 Pressure gauge, 20 645 Pressure gradients, flow caused by, 9 110 Pressure infiltration, of metal-matrix composites, 76 167-169 Pressure injection, moldings, 10 11 Pressure-jump method, 73 427-428... 

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. 

Like horizontal belt filters, the indexing belt filters are operated semicontinuously under vacuum or pressure. The belt is stationary during filtration and indexes forward for cake discharge. Dispos-... 

In these designs, horizontal belt, disc or drum filters are installed inside pressure vessels. Sufhcient room is provided in the latter for access by personnel, cake discharge, etc. Such plants are operated under con ressed air blankets, alone or in conjunction with vaccvun downstream of the filter. 

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... 

The vacuum is created behind the filter medium, which causes the atmospheric pressure in front of the filter medium to drive the slurry through the medium, filtering out suspended solids in the process. Types of vacuum filters include belt, horizontal pan, vertical disc, and dmm varieties. 

As much as the vacuum horizontal belt filters have made a considerable impact in vacuum filtration, one would expect that the same principle may be used in pressure filtration, by enclosing the whole or part of the belt in a pressure vessel. This idea has to be seen as entirely separate from the so-called belt presses (section 12.3.5.1) which use the squeezing of cake by a second belt and do not use the pressure of the liquid or air to drive the filtrate through and out of the cake. 

Another possibility is to enclose only the working, top part of die horizontal belt in the pressure vessel and to pass the belt through the sides of the vessel. Inevitably, the operation has to be intermittent because the belt cannot be dragged over the support surface with the pressure on and, also, the entrance and exit ports for the belt must be sealed during operation to prevent excessive losses of air. The movement of the belt is intermittent, therefore, and is synchronized with decompression in the vessel. This means that the whole of the vessel volume must be depressurized in every cycle and this is wasteful there is also the inevitable down-time involved but there are no problems with discharging the cake because this is done at atmospheric pressure. Strictly speaking, such filters do not fall in the scope of this review because the movement is not continuous, and they are only briefly reviewed in the following. 

The proposed layout is shown in Figure 9.49. The feed is pumped by a high-pressure pump to spray nozzles. These nozzles can be arranged in various configurations. Here, the spray from the nozzles travels horizontally and then turns down due to gravity. The dried powders are then transported by a conveying belt at the bottom and also conveyed to cyclones or bag filters. 

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