Chamber Filter Presses

Traditional recessed chamber filter press operation employs a steady increase in pressure over time as the cake thickness increases, in order to achieve the optimum combination of chamber filling and cake dryness. At a significantly reduced filtrate rate, the filtration is stopped, the press discharged and a new cycle started.

Chamber filter presses are reliable and robust in many different applications. The plate pack consists of uniform chamber plates with a recess of 15 - 50 mm to receive the filter cake. A chamber plate is a combination of a filter plate and two frames in once piece. The standard material for chamber plates is Polypropylene. Possible operating pressures: 6, 15 and 30 bar.

Membrane Filter Presses

During the initial phase of the filtration cycle, so-called “fill and filtration” the process is similar to the chamber filter press. After reaching a predefined pressure, usually around 4-10 bar, depending on the sludge characteristics, sludge feeding is stopped and the membranes slowly inflated, using either water or air as squeeze medium. The cake is hereby compressed and dewatered further. This process is continued until the filtrate flow reaches a preset minimum limit. Then the squeeze medium is relieved and the cake discharged.

Membrane filter plates are designed just like the previously described chamber plates. A flexible membrane is fixed to the support body. Materials for the membranes include Polypropylene, synthetic rubber (for example NBR, EPDM) or thermoplastic elastomer (TPE). Special materials such as PVDF are also available. The membrane is impermeable and serves to compress the cake within the chamber after the filtration process is complete. Liquid or gas (compressed-air) can be used as membrane inflation media. In order to guarantee maximum protection for the membrane filter press, we use special safety systems for the various membrane inflation media. Inflation pressures up to 30 bar, and in special cases even higher, are possible.

Plate & Frame Filter Presses -Sheet Filters

The chambers of this type of filter press are formed by combining Polypropylene filter plates and frames. This creates chambers of 5 - 40 mm, depending on frame thickness. Plate and frame type filter presses are suitable for pre-coating filtration, which in the beverage industry, is used for clear filtration. ANDRITZ supplies plate and frame type filter presses for operating pressures up to 6 bar.