Top Feed Filter 3

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TOP FEED FILTER

Page 3

Top of Swenson Top-feed filter, showing feed arrangement and dewatering zone. Note uniform cake formation.

CAKE WASHING - Where wash water is used, it must not be applied against the surface of the drum below a point approximately 45º from the vertical, or the water is apt to run down into the finished product and defeat the purpose of the filter. The top-feed filter has a limited space, after the cake has been formed, where wash water can safely be applied. Generally this is sufficient, provided thorough washing is not required.

CRUST REMOVAL - The liquor in the cake, during heating with hot air, becomes more highly saturated with the salt. As this liquor evaporates, the crystals on the surface of the cake tend to become cemented into a crust which is removed by an intermediate scraper to expose a fresh semi-dried surface to the hot gases and also leaves a thinner cake, thereby allowing a faster flow of hot air through the cake during the final drying part of the cycle.

CLOTH BLINDING - The highly concentrated liquor produced by the heating of the cake finds its way into the meshes of the filter medium, on which a hard crust is formed by the evaporation of this liquor. In some cases, this crust can be broken up with a spray of filtrate or brine under pressure, but generally a light spray of water is necessary. Water so used finds its way into the system and must be taken into account in subsequent operations.

STANDARD SIZES - The Swenson top-feed filter is available in the following standard sizes:

Drum	Drum	Area of
Diameter	Length	filter surface
6 ft.	2 ft.	37.5 sq. ft.
6 ft.	3 ft.	56.25 sq. ft.
6 ft.	4 ft.	75 sq. ft.
6 ft.	5 ft.	93.75 sq. ft.
6 ft.	6 ft.	112.5 sq. ft.
6 ft.	7 ft.	131.25 sq. ft.
6 ft.	8 ft.	150 sq. ft.

SWENSON FILTERS CAN BE ADAPTED TO YOUR INDIVIDUAL PROBLEM

Since every filtration problem requires special treatment, the success of any installation depends largely upon the skill and experience of the equipment builder. In some cases, a thorough knowledge of the interlocking operation will enable him to recommend equipment and process changes that entail substantial economies.

The extensive experience of Swenson in the design, construction and operation of top-feed filters (as well as evaporators, crystallizers, and dryers which are often used in conjunction with filtration) makes Swenson especially well qualified to help solve your individual needs.