Technical Bulletin 1
Determination of rinse water contamination following pretreatment process stages.
During the water rinsing stage of any pre-treatment process, contamination will build up in the system. It is therefore essential to monitor and control the rinse water during the following Aquus®
Alkali degreasing solutions
Iron phosphate treatments
The testing and control is critical to ensure optimum performance and to ensure subsequent process stages are not contaminated.
At the same time increasing rinse contamination can indicate excessive chemical carry over due to misaligned spray jets.
A Rinse Contamination Pointage is measured which indicates the level of contamination.
Rinse Contamination Pointage Determination
Refer to the Technical data sheet of the Aquus®
process you are using.
Take a 50 ml sample of the rinse to be tested and add a few drops of indicator used for the Aquus®
product process stage. Titrate with the same testing solution to the end point. Note the number of mls of testing solution used. The number of mls used is referred to as the Rinse Contamination Pointage.
In general if only one rinse is used between process stages the Rinse Contamination Pointage should be kept below one. If two rinse stages are used then the first can operate with a Rinse Contamination Pointage of 2.0 and the second one with 1 point. Counter flowing rinses will reduce water consumption whilst maintaining rinse quality. In certain situations it may be necessary to operate at different parameters.
EnviroTech Europe Ltd will advise if this is required.
For more information or advice please contact us by telephone on +44(0)20 8281 6370 or email us using our contact form.
Aquus® Thin Layer Pretreatment Processes are supplied and supported by EnviroTech Europe Ltd.