Dewatering is a process that separates a mixture of solids to the liquids. The main purpose of dewatering is to keep the liquid content out of the solid elements. For a very long time, construction and industrial projects have been practicing the process of dewatering to keep their respective projects going.
There are two primary principles of dewatering. The first one is sedimentation. Sedimentation uses either gravity or other means of centrifugal force to separate solid elements from liquids. Another principle is filtration. With filtration, a means of filter media is used to separate solids from liquids.
In dewatering, vibrating screens can recover almost all solid particles from liquids, mud, or sludge. To date, there are two types of vibrating screens that can be used for dewatering applications.
The structure of an inclined dewatering screen can make the slurry travel towards the discharge end. The water on this material will then be filtered and screened out through the proper screening media. Gravity that is enhanced by the vertical vector of the g-forces can make the water be completely separated from the solid materials.
While inclined dewatering screen can certainly do the filtration work, the gravitational forces on this type of vibrating screen can drag the water back into the filtered product when the material is transported. One solution to this problem is to decrease the inclination of the screen. However, doing this adjustment can make your product end up a little bit wet since the material travel rate will drastically decrease.
One key problem in using an inclined dewatering screen is its final product. Some products from this dewatering screen might have a high amount of water. Once this type of product flows back on a conveyor belt, it will surely cause damage to the belt rollers. Moreover, consumers who might even avoid paying up for products out of the inclined dewatering screen.
The incline of horizontal screens is not 100% flat. In fact, horizontal dewatering screens have a negative incline of about 3°. The g-force produced by this type of screen is aligned in a 45° and transports the material uphill. Enhanced by the vertical portion of the acceleration, the gravitational forces of this type of screen is fully utilised towards the dewatering process.
Operating with these forces, the horizontal dewatering screen will build a material layer on the screen out of the slurry. This material layer is pushed out of the wet zone towards the discharge end. Moreover, the amount of water right after feeding the screen is lessened with the help of the back dewatering field. As the material layer gets thicker, the liquid part from the slurry is then pressed out. Fine particles are also trapped by this thick material layer. The dam at the discharge end then enhances the quality of the filtered product.
In summary, dewatering screens can separate the liquid part from the solid part if there is a large angle between the material transport and gravity. Moreover, the material loss is minimised if there are filter-cake bridge openings.
Dewatering is mostly practiced in construction and industrial projects since it can provide dry solid elements with extremely fine particles. The use of vibrating screens is cost-effective since it won’t be wasting any materials. To know more about dewatering and the wonders of vibrating screens, you can contact us now at Hawk Machinery.