Vacuum filters horizontal rotary

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 ). 

Disk Filters Disk filters consist of a number of concentric disks mounted on a horizontal rotary shaft. The operating principle is the same as that of rotary-drum vacuum filters. The basic design is illustrated in Figure 22. The disks are formed by using V-shaped hollow sectors assembled radially about a central shaft. Each sector is covered with filter cloth and has an outlet nipple coimected to a manifold... 

The horizontal rotary table filter incorporates, as its name suggests, a horizontal rotary circular table divided into segments or drainage compartments, each of which is ported to a rotary valve underneath the table. The top surface of the table is fitted with a filter medium and walls are provided around the periphery of the table and around the hub. The feed slurry is distributed across the table through a feed box and vacuum is applied to... 

Vacuum filters include the nulschc filter, enclosed agitated vacuum fillers, the vacuum leaf filter, the tipping pan filter, horizontal rotating pan filters, horizontal belt vacuum fillers, rotary vacuum drum lilters. and rotary vacuum disk filters. 

Horizontal vacuum filters are found in two basic designs, rotary circular and belt filters. They provide flexibility in cake thickness, washing configuration, and drying time. They are effective for heavy dease solids, but they are anpensive, require a large floor space, and are difficalr to enclose for hazardous applications. 

Rotary-drum filter. The most common type of continuous vacuum filter is the rotary-drum filter illustrated in Fig. 30.8. A horizontal drum with a slotted face turns at 0.1 to 2 r/min in an agitated slurry trough. A filter medium, such as canvas, covers the face of the drum, which is partly submerged in the liquid. Under the slotted cylindrical face of the main drum is a second, smaller drum with a solid surface. Between the two drums are radial partitions dividing the annular space into separate compartments, each connected by an internal pipe to one hole in the rotating plate of the rotary valve. Vacuum and air are alternately applied to... 

Horizontal Vacuum Filters These filters are generally classified into two broad classes rotary circular and belt-type units. Regardless of geometry, they have similar advantages and limitations. They pro-... 

Rotary Drum Vacuum Filters. This filter can accommodate a large thickness of cake and can take a precoat of filter aid which is up to 150 mm in depth. The feed su ension is filtered onto the precoat and the filtered solids together with a thin layer of precoat is scraped off the cake sur ce by a horizontal knife situated just before the surface passes back into the feed suqiension tank, thus e qposing a fi esh surface of precoat. The scraper knife advances automatically until it reaches a mioimum distance fi-om the cloth, usually 5-10 mm. At this point the cycle is finished and the filter is cleaned of used precoat. 

Figure 5. Cross section of a rotary horizontal vacuum filter showing filtrate removal system, filter cloth and discharge scroll.

Continuous filtration is discussed by Coulson and Richardson.. It commonly employs rotary vacuum filters. These are usually cylindrical in shape, rotating about a horizontal axis with a filter medium on the curved surface and a vacuum applied from inside. Rotating disc filters are less frequently employed (see Fig. 2.4). These have a number of discs on the same shaft with vacuum applied from inside but the flat surfaces of the discs hold the filter medium. The methods of continuous discharge of the filter cake during operation, and of replacement of the filter medium at intervals, are less elegant than those applicable to rotating cylinders. 

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