Decontamination of dry cleaning machines

Front View: Open container with machine to be cleaned!
Rear View: Container and active carbon filter!

„We only live once on this planet. Maybe no one cares how irresponsible people sometimes handle solvents!“
- Frank Ziermann

For more then 30 years the Ziermann Company has been selling second hand dry cleaning machines in south west Germany, Luxembourg and recently in parts of Switzerland, too.
These dry cleaning machines contain up to 1,000 litres of solvent, mostly Tetrachloroethene, formally known as Perchloroethylene or PERC. After shutting down there still remain up to 50 litres of solvent in the machine. This solvent residual (approx. several thousand litres each year) evaporates unnoticed during the shut down. This contaminates the environment on an unknown scale.

Ziermann developed a plant to remove the solvent residuals.
With this new method the solvent residuals will be vaporized. According to German law this can only be carried out in closed containers. Our new system allows us to do so in accordance with German law, especially paragraph 2. This means a new level of technology has been developed. Up till today Ziermann is the only dealer worldwide selling second hand dry cleaning machines free of solvent residuals.  

This device is a container whose floor and lower area (up to 2 meters) are sealed to a tub with air-tight welds.
The air is taken away via 2 active carbon filters with 600 kg of active carbon in each.

The principle of this decontamination device is vaporization.
For this purpose the second hand machine is placed in this container. All the tanks, water separators and the still are opened. All the sliders are opened with special clamps to keep them open. Warm air is blown with flexible hoses on to the critical parts and pumped out afterwards. After this is done the container is made airtight again and locked and the air is pumped over the active carbon filters. There is a vacuum at all times in the container during this process. 

Now the solvent residuals are vaporized with hot steam and filtered. 
So that the machine to be cleaned is not damaged the temperature is limited to 60 °C. In the first stage of heating the air is contaminated with PERC. It is guided into the cooler where most of the PERC then condenses. This condensate then goes through the water condenser into the solvent tank. At the end of this stage the air flows back. If the measuring computer records a too low concentration the air flow is switched to the active carbon unit to bind the unbound solvent. The device works with 2 active carbon filters, which work alternately. While one filter absorbs the solvent the other one is cleaned with steam and the solvent is recovered. The saturated carbon gets boiled in this process. Because of the desorption the carbon and solvent will be divided. Afterwards both are completely fit to be used again. The water which was used to clean the carbon will be recycled in the contact water device. The treatment of the second hand machine is over as soon as the PERC concentration in the container is below a certain level (MAK, Air threshold limit in the workplace TRGS 900 = 345 mg/m³ respectively 50 ml/m³) at a temperature of 20 °C. Then the measuring computer releases the loading door. The decontaminated machine can be safely taken out.

Environmental protection is most important for Frank Ziermann.
He wants to be a role model with this device and therefore he did not patent this technology!

Capacity
Machines up to 5 tons.

Temperature
60 °C

Container Dimensions
5.000 x 3.200 x 3.200 mm (L x W x H)

Performance
4 machine-loads per day (2 hours per load)

Components
Container with reservoir, 2 active carbon filters with 600 kg carbon each, steam heated air heaters, coolers, water separator, solvent tanks, control (measuring computer, 2* SPS 300)

Special Feature
First machine worldwide complying completely with the German Immision Law (§ 13, paragraph 2)