Hot hydrochloric acid is pumped through the roll for 24 hours and then neutralised and flushed with water. If you have a roll that is overheating or is not getting sufficient flow, this acid clean process can often remove corrosion or a blockage and restore normal flow through the roll and bring it back to a normal working condition.
We often get asked to internal clean rolls on site. Whenever we have come across a company that offers on-site internal cleaning processes, this has always turned out to be a cleaned using citric acid, which is much milder and much less effective at removing corrosion as the hydrochloric acid used by BEP. Citric acid is also much safer to transport, which is why this process can be used on site. Our more effective internal clean can only be performed at our factory.
We often receive rolls for surface or journal repairs without the customer requesting an internal clean. Whenever this happens we always ask our customer if they want the refurbished roll to be acid cleaned as well. The usual response is ‘No, we are not having any problems with flow through that roll at the moment’.
The view that an internal clean is something that only needs to be done to fix a problem once it occurs can be short sighted. At BEP, we like to encourage our customers to view internal cleaning as part of the scheduled maintenance that should be done regularly to prevent problems caused by blockages or low flow from occurring in the first place. This ensures that the roll operates and performs as it was designed!
BEP can ensure the internal clean can be planned ahead of time to limit any effects on production. In some severe cases where a roll has gone too long without an internal clean, the corrosion build-up can be so severe that the internal clean is not able to fix it and the roller may have to be scrapped.
A regular internal clean can avoid this problem by making sure corrosion is kept to a minimum at all times and ensures your rolls perform as intended.