Chespa Flexosysteme, a young printing ink manufacturing company located in Leipzig, Germany is a single source provider of printing forms, printing inks and cutting dies.
Employing a 300-strong workforce spread over six sites, Chespa manufactures printing forms and photopolymer sleeves at its main Poland facility in addition to printing inks and cutting dies while photopolymer flexo printing and coating plates are produced in Leipzig.
Chespa relies on well-established international suppliers such as Dupont de Nemours, the Flint Group and also MacDermid for printing plates in thicknesses of 0.76mm to 6mm. The group as a whole supports customers in Germany, Switzerland and Eastern Europe, including Belarus, the Ukraine and all of Russia.
Distilling solvent-based washout solutions with limited capacity, Chespa decided to establish a new distillation plant with appropriate capacity to support plate production of 3,000m² per annum. The aim was to achieve a continuous distillation rate of 50-60 litres per hour for distilling and recovering the FlexoSol washout solution.
The search for a suitable supplier of a new solvent distillation plant became a matter of extreme urgency, especially with a new EU-supported investment program for the German state of Saxony. Chespa Flexosysteme wanted to make optimum use of the funding as part of its modernisation plans.
Following a comparison of three manufacturers of solvent distillation units, a decision was made in favour of OFRU Recycling for the good price-performance ratio, the design with its steam heating technology and the steep conical distillation vessel with its easy cleaning potential.
Integration into the printing plate production
The solvent distillation plant had to be integrated into the printing plate production process. The prepress stage at Chespa Flexosysteme is created digitally and the printing plates are produced by CDI using an ESCO Cyrel Digital Imager Advance 5080.
After the imaging process, the photopolymer flexo printing plates or coating plates are exposed to light in a Dupont de Nemours exposure unit/finisher and subsequently processed further in a plate treatment system. Two Dupont de Nemours washout units are used for this process.
Flat brushes oscillate inside the processing unit and round brushes rotate in the opposite direction, washing out any plate parts that are not exposed to light during the different washing cycles. FlexoSol from Dupont de Nemours is used to dissolve the polymers.
Fresh solvent is stored in a tank that is connected to two washout units, with several pumps supplying the processing units and the solvent tanks in the process. The tanks from the old distillation plant, each with a volume of 1,000 litres were smoothly connected to the OFRU solvent distillation plant.
The ASC-150 solvent distillation plant
An OFRU ASC-150 24 kW distillation plant was selected and installed to recover and distil the FlexoSol. The solvent recycling plant is the smallest unit within the professional ASC series that has an integrated steam heating generator.
A small amount of water is heated up instead of thermal oil and saturated steam is produced at max. 10 bar, a process that takes about one hour. High output rates of FlexoSol can be achieved over the course of a day with a relatively small distillation vessel due to the high energy density of the steam within the heating jacket.
The distillation plant is filled in a fully automated process. The fill level of solvent in the plant is around 80 litres and is always kept at a constant level. The plant only halts the filling process at the end of the continuous distillation period (approx. 6 hours) and concentrates the FlexoSol solvent at a predetermined viscosity and residual solvent content.
Scrapers with strong contact pressure on the inner walls of the vessel guarantee optimum distillation with simultaneous cleaning. The energy yield is extremely high and the steep angle enhances the removal of polymer residue.
At the end of the sump distillation period the plant automatically drains from the bottom of the unit into 200-litre drums. A roller conveyor facilitates the loading of drums onto Euro pallets for disposal of the residual waste at a later date. Both the drums and their contents are incinerated when disposing of the residual waste.
Chespa Flexosysteme currently operates the ASC-150 distillation plant with 24 kW steam heating for a few hours each day in an 8-hour operation. The constant output rate is around 50-65 litres per hour and about 78 litres at peak times. At the end of the day, 400 litres of clean FlexoSol are available for the reproduction operation.
The Chespa group has placed itself in a strategic position within Germany and the Eastern Europe markets at an excellent time by investing in modern production and environmental technology.
Recovering FlexoSol in-house with an OFRU ASC-150 distillation plant has brought several benefits to Chespa.
Key benefits derived by Chespa:
- Current requirement of only about one ton of fresh solvent each month against three times higher quantity previously
- Eliminates the need to distil the solvent using an external recovery source
- Quick return on investment
- Continued business expansion will soon lead to 24-hour operation of the distillation plant