While some small disc filters operating a slow speed use scrapers, or wires, that touch the cloth, most large disc filters do not, since the disc sectors are cantilevered out from a central barrel and the tolerance needed, on the scale of millimetres, is not possible. In some cases, simply removing vacuum from the sector (using a blocking bridge in the control valve) will be enough. It is far less common to use disc filters for washing than (say) drum, pan or belt filters.Īir drying takes place between from the time that the sector emerges from the slurry and continues until cake discharges – usually lasting for about one-third of the rotation time (the equivalent of about 120°).Īfter air drying, the sector experiences a sharp back-pulse of air and this expands the cloth that covers the sector and the cake falls into the cake chute. However, since the cakes are vertical, the wash liquid must be sprayed onto the cake surface. As with other rotary vacuum filters, there is relatively little flexibility in the cycle (the ratio of filtration time to air-drying time is fixed by the compartmentalization of the control valve and there is almost no flexibility in the slurry height (in contrast to a vacuum drum filter)).Ĭake washing can be performed on a vacuum disc filter, once the sector has emerged from the trough. The slurry feed can either be controlled by a feed valve/level sensor or can be set at a standard rate (if the slurry composition, vacuum and cloth condition remain constant then so will the throughput) with a weir overflow sending surplus slurry back to the feed tank.Ĭake formation and filtration occur during the time that the sector spends in the trough. The slurry is normally fed directly into the slurry trough. In some cases an agitator system may be needed. The larger surface area rotating through the trough (compared to a drum filter of similar overall size) means that the slurry is more highly agitated by the filter itself. This trough may be partly compartmentalized in order to reduce the volume held in it at any one time (and therefore reduce the residence time of slurry in the trough). The barrel is supported on bearings and may be either directly driven by a motor or indirectly through a gearbox. A number of discs can be fitted to the same central barrel. Each sector is connected to the control plate by individual pipes (or hoses) or through fabricated channels in the central barrel to form a disc. The filter cloth is usually supplied as a cone, which is fitted over the sector and sealed top and bottom. Cake discharge usually occurs at atmospheric pressure via a scraper blade.įigure 4.25. Both cake deliquoring by gas blowing and displacement washing, can be performed reasonably effectively at different pressures through a multi-compartment arrangement within the housing. Raised temperatures can be accommodated as can volatile and toxic feeds. Rather than applying a vacuum inside the compartments of the drum, the pressure inside the housing is raised by compressed gas up to 800 kPa and this facilitates constant pressure filtration at the outer drum surfaces. It comprises a rotating, bottom-fed drum of area up to 120 m 2 enclosed within a sealed housing. The rotary pressure drum filter is similar in principle and basic form to the rotary vacuum drum filter (see Section 1.4.1.5). Typical particle size and feed concentration range: 1–100 μm and 5–30+% w/w. Typical uses: Continuous separation of finer particle suspensions where cakes require post treatment. Wakeman, in Solid/Liquid Separation, 2007 Rotary pressure drum With thousands of quality suppliers & manufacturers, we are sure that they can provide all equipment for sale, services and solutions for your various industrial applications.E.S. It's well known that product quality and safety is a stronger priority for this equipment industry and also for the buyers, here you are offered a greater chance to find trustworthy manufacturers & factories who are delivering high levels of performance, efficiency and reliability in their products all the time. Besides, their competitive & cheap price of Rotary Drum Filter factory would get you an edge in your own market.
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