Filter presses are manufactured to separate solids from liquids. They comprise of several main components including the press frame, plate pack, filter cloths and various modular components for the automation of the operating sequences.

When a suspension flows against a textile weave (filter cloth) that is permeable for liquids only, the solids are retained on this cloth. During filtration, the solids accumulate to form a filter cake on the filter cloth.

The liquid portion of the suspension permeates through the filter cloth and is recovered as a solid-free filtrate. The filter cloth and filter cake form a resistance against the flow. As the filter cake increases, more and more pressure is required to overcome this resistance. Once a compact filter cake is formed inside the filter press, it will be discharged after the filter press is opened.

The plate pack consists of individual filter plates. The filter plates are covered with filter cloths. Due to the geometric shape of the filter plates, chambers are formed inside the plate pack when the filter press is closed. The chambers are filled with suspension through corresponding feeding holes in the filter plates and filter cloths. During filtration, the hydraulic closing device of the filter press frame firmly presses the filter plates together and prevents the opening of the filter plates at high filtration pressure. After the filtration cycle, the feed ports are then blown out using air (core blowing) and the plates mechanically separated from each other, allowing cakes to drop out to the bottom of the press. After discharge of all cakes the press is closed again for the next cycle.

Filtration System Selection

Because of its simplicity and flexibility, the chamber filter press has been widely applied in clarification and dewatering applications. Membrane filter press technology is gaining increased acceptance because it reduces subsequent processing or disposal costs for filter cake. In many applications the membrane filter press significantly reduces residual moisture content, making this technology attractive for new plants and for upgrading existing facilities. In both cases the careful selection of plate and membrane materials is essential to the successful performance of the process.

Filter Press Types

Product Washing

Many products contain significant amounts of dissolved material in the liquid phase. The removal of these solutes is often a key process step in reducing impurity levels, where the filter cake is the final product, or recovering dissolved solids where the filtered liquid is the product.

In all cases, the minimization of wash liquid quantity and washing time has absolute priority.

Process Flexibility

A unique advantage of the filter press is the capability to combine several process stages in one operating unit, while independently controlling the relationship between these steps to achieve optimal performance. Factors such as cake compression and permeability, operating temperature and pressure gradients all play a role in the capital investment and operating costs. The correct design and control of peripheral equipment, such as feed and wash pumps and membrane squeeze systems are required to optimise costs.

Due to the optimum adaptation of the process parameters (throughput, pressure, time) with the suspension, as well as the correct selection of materials (filter cloth, filter plate), our filter presses achieve optimum filtration results in various applications. All process sequences can be completely automated.

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