Horizontal tank-vertical leaf filters

For more efficient leaf cleaning, horizontal tank-vertical leaf filters are made with various types of movable sluices. 

Various filter designs are available to the industry, including plate and frame filter presses, horizontal tank/ vertical leaf pressure filters with retractable bundles or shells, and vertical tank/vertical leaf pressure filters. The latter (Figure 29) has been accepted by the industry as perhaps the best overall choice in terms of price, performance, space requirements, and ease of automation. Filter sizes up to 85-m filter area/filter are available with this model. However, the horizontal tank/vertical leaf model with either retractable bundle or retractable shell also has its proponents. Commonly, a major factor in deciding on this type filter is the fact that these units are available in sizes up to 200-m filter area/filter. 

Horizontal Tank-Vertical Leaf ("H" Style) Filters... 

Pressure-vessel leaf filters (a) vertical-tank, vertical-leaf filter, and (b) horizontal-leaf filter. 

In comparison with nutsche filters, leaf filters provide more filtration area in the same volume of a pressure vessel. They are more suitable for handling larger quantities of slurry. Leaf filters can be subdivided into four classes in accord with the vertical or horizontal position of the tanks and leaves. In Figures 22.32 and 22.33, vertical leaves are shown in vertical and horizontal tanks. For vertical leaf filters, to prevent cake dropping, the cake thickness is normally restricted to 3.5 to 4.0... 

Pressure Leaf Filters Sometimes called tank filters, they consist of flat filtering elements (leaves) supported in a pressure shell. The leaves are circ ilar, arc-sided, or rectangular, and they have filtering surfaces on both faces. The shell is a cylindrical or conical tank. Its axis may be horizontal or vertical, and the filter type is described by its shell axis orientation. 

Sheli-and-leaf filters. For filtering under higher pressures than are possible in a plate-and-frame press, to economize on labor, or where more effectivv washing of tlie cake is necessary, a shell-and-leaf filter may be used. In the horizontal-tank design shown in Fig. 30.6 a set of vertical leaves is held on a retractable rack. The... 

Many types of filter are supplied for this sort of operation. In chlor-alkali brine treatment, the two most frequently encountered are the pressure leaf filter and the candle filter. Both types are capable of removing submicron particles and producing a filtrate with less than 1 ppm of suspended solids. A leaf filter, as the name implies, contains a number of thin, flat elements that are active on both sides. In chlor-alkali brine plants, the leaves normally are suspended vertically in a tank. The tank may be horizontal, in which case the leaves are circles or rounded squares, or vertical, in which case the leaves are approximately rectangular and of different widths. 

The tank-leaf pressure filter (Figure 50.4) features a number of leaves (filtering elements) suspended within a closed vessel. Common variations involve the arrangement of the tank and leaves into various vertical and horizontal combinations. Vertical tanks normally contain vertical leaves whereas horizontal tanks may have either vertical or horizontal leaves. The leaves are hollow shells fitted with support grids and covered with a metal gauze or woven fabric. They... 

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