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12 Solvent Inspection and Care 12
The most important factor in solvent inspection and care is the use of high-quality perc and suitable
chemical additives. The drycleaning detergent, in particular, should contain solvent-stabilizing
components.
The pH value is an important indicator for the quality of the solvent. In a well-run operation, the value
should be determined once a month as a matter of course.
Solvent care is an essential factor in the reliability and long-life of the machine and in the quality of the
cleaning that the garments receive. It includes routine maintenance of the still and water separator and
the use of quality products.
Because of the small amount of solvent used, we recommend that you add neutralizing, acid-binding
adsorbents to the still as preventive neutralization.
-Determining the pH value:
Remove a few cm
3
of water from the water separator/safety separator and place in a test tube.
Then dip the indicator paper into the water and determine the pH value by using the comparison
scale.
It is not possible to measure the solvent directly.
pH value
Reaction Measure
Under 5 Solvent highly acidic Replace solvent
5 - 6 Solvent slightly acidic Neutralize solvent
7 - 9 Good solvent condition
Over 9 Solvent alkaline Determine the cause and correct
Possible causes of an acidic reaction:
- Instable solvent
- Steam temperature too high (solvent decomposition with acid formation)
- Unwanted addition of acids
- Incorrect solvent
- Bad quality of the solvent - new garments
Possible causes of alkaline reaction:
- Highly alkaline pre-spotter or chemical additives
(nitrogen compounds, ammonia)
- Overstabilized solvent
- Garments containing a high level of sweat.
P12
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