Liquid filtration using fully automatic wedge wire filters

Self-cleaning filter system by contec in the production of chocolate

and in the filtration of high viscous polymer bitumen

contec GmbH, Bad Honnef is a leading supplier of filtration systems, oil mist separators, dust collectors and liquid level measuring technology. The significant market position of the contec GmbH is based on the well-established technologies and successfully new product developments. In the field of new development again, a successful example of application in the production of chocolate and of cold self-adhesive vapour barrier sheets for large roofs with bitumen can be documented.

The filtration challenge at filtration of bitumen:

- Medium: viscous polymer bitumen for cold self-adhesive vapour barrier sheets

- Liquid temperature: approx. 130°C

- Viscosity @ 130°C: about 100,000 mPas

- Viscosity @ 140°C: about 45,000 mPas

As a subsidiary of a leading international supplier of construction adhesives, Rasco GmbH in Augustdorf, Germany produces cold gluing thin bitumen sheets for roof areas of more than 2,500 m² with a thickness of approximately 0.3 mm. Because of the required low coat thickness problems in production are unavoidable. Polymer bitumen at 140°C is applied with a layer thickness of = 0.3 mm on a plastic laminated carrier sheet.

To avoid malfunctions during the production process, it is necessary to filter the hot polymer bitumen composition. However, due to the high viscosity of the material with decreasing temperature, disassembly and maintenance of the filter are possible only at full working temperature.

The solution:

The hot bitumen compound is filtered through a newly developed wedge wire filter by Contec® with hinged lid and internal clutch. In addition, the filter is equipped with a heating jacket through which it can be integrated into the existing factory thermal oil plant. By this construction a tool-free removal of the filter element is possible at full working temperature. The filter holds back the clumping reliably, so that production takes place smoothly and trouble-free.

The filtration challenge at filtration of chocolate:

The chocolate manufacturer Ludwig Weinrich GmbH & Co. KG, Germany wanted to replace the previously used sieve filters (last step before molding) through a self-cleaning filter system as police filter before filling the chocolate.

- Medium: Chocolate

- Viscosity: 1.5 PaS - 7.5 PaS

- Throughput: about 1.5 t/h

- Pressure max.: 6 bar, max. temperature: 40 °C

- Fineness: 1.5 - 2 mm in order to prevent separation of the chocolate

The solution:

After a very successful trial with an wedge wire filter type AS110K standard of contec this was modified for special use as follows:

- The filter is easy to open with a hinged lid.

- The filter element with the scraper basket can be removed completely to the top without tools.

- By means of a heating jacket, the filter can be integrated into the existing tracing.

- An integrated magnetic separator after the filter system provides ultimate security.

- The discharge is carried out in 3” in order to ensure an easy emptying of the filter.

The company Weinrich GmbH & Co. KG has installed differential pressure monitoring line and found out that the pressure loss is only 0.1 to 0.2 bar.