Filter plates

General information

Sturdy filter plates are produced in a high-pressure die casting process. The polypropylene is melted and then packed under high pressure. This is the only way to produce a durable filter plate which can resist the high contact pressure of the cylinder in a filter press.

The channels and holes are then created with mechanical processes.

In the field of wastewater treatment and environmental protection as well as in the chemical industry, non-corrosive materials such as polypropylene or PVDF (particularly chemically inert) are preferred. The high quality plates have smooth surfaces and can be cleaned easily, e.g. with a pressure washer.

The filter plates have to support the filter cloths, introduce the suspension and discharge the filtrate as well as seal against one another. They have to resist processing conditions such as pressure, chemicals and high temperatures. All these functions can only be provided if the filter plates have the corresponding level of quality.

During operation, the filter plates are pushed together by a cylinder and move on the booms of the filter press. Two filter plates form the chamber volume for the solid to be filtered out in the plate package (filter plates pushed together) of the filter press.

Materials

Polypropylene filter plates are most commonly used for filter presses. But there is also a range of options, e.g. for certain chemicals (e.g. PVDF) or high temperatures (e.g. Nylon^®). Putsch^® offers advice for specific inquiries as to which materials is the best solution for durable filter plates.

Precision fit

It is particularly important that filter cloths rest fully against the plate and seal against each other to the outside in the plate package. For filter plates, Putsch^® places a special focus in e.g. dimensional stability and durability of the material, which sets the product quality apart from many other manufacturers. After all, filter plates have to last for a long time under the extreme conditions such as the contact pressure in the filter press and have to survive many cycles.

Product variants

During operation, the filter plates are pushed together by a cylinder and move on the booms of the filter press. Two filter plates form the chamber volume for the solid to be filtered out in the plate package (filter plates pushed together) of the filter press. Chamber plates with different chamber depths are available for the corresponding chamber volumes.

For open filter plates, the filtrate exits at the side of each chamber, is collected in a channel and discharged on the filter press. The operator can read out the filtration result (cloudiness) on the filtrate to control the filtration process in each chamber.

When the filter plates are closed, the filtrate flows through internal channels in the filter plates and into a discharge pipe. This design is particularly common for processes with large emissions quantities and the use of hazardous substances.

The hole in the filter plate for the suspension can be on any corner (corner intake) or at the center (central intake).

Each filter plate has handles which glide on the booms of the filter press. Information about the dimensions and the profile of the booms are important for achieving the ideal running characteristics.

Depending on the filter press used, the corresponding filter plates are available in different formats. Large filter plates feature tappets which ensure the stability of the plates during pressure transfer.

The first filter plate in the plate package is the head plate. Usually, one side is level and only the other side has a chamber depression for the filter cake. The last plate is the end plate which is also only designed for a single-sided filter cake.

In addition to chamber presses, membrane filter presses are also available. The membrane filter plates are positioned in the plate package and feature an expanding layer made of hard rubber or polypropylene for pressing the filter cake in the chamber. The advantage here is that the operating cycle of the filter press can be reduced. The operator independently determines the end of the filtration process and does not wait until the chamber is filled with solids and the pressing mode of the filter press starts.

On non-drip filter plates, the filter chamber is sealed with a continuous seal. Special filter cloths are inserted into the precision groove.

In addition, many other special filter plates are available, e.g. washing plates.

Putsch^® has a team of experts who are familiar with all types and versions of filter plates, can address your special requests and provide competent advice on selecting the correct filter plate. Putsch^® usually already finds the best filter plate solution based on a drawing or sample.

Cleaning

The smooth surfaces and clean machining, e.g. of the welding seams and depressions, allow fast and thorough cleaning of the Putsch^® filter plates.

Accessories

Putsch^® offers different scrapers for cleaning the filter plates and filter cloths – made from different materials and with different levels of hardness.

Technical data	Filter plates
Material	Polypropylene (standard), PVDF (optional), Nylon® (optional)
Filter plate size	250 – 1500 mm edge length (others available on request)
Max. operating temperature for polypropylene	80 °C at max. 8 bar filtration pressure or 40 °C at max. 15 bar filtration pressure
Application examples	Electroplating and communal wastewater, chemicals