pretreatment systems settlement tank

Pretreatment Systems Decontamination

Pretreatment systems operate by dipping components or spraying a product as it is conveyed through the system. It can become an inherently messy processes.  Once a water-based tank becomes over-saturated with oil, grease and dirt from recently manufactured components, it will gradually decrease in its ability to operate to the specification for which it was designed.


The Importance of System Maintenance

The longer a system runs without scheduled maintenance clean down and replenish, the further away from its design parameters it will become.  The problem can be exacerbated if a particularly “dirty” process is required to manufacture a product that requires pre-treatment. Such as deep-drawn dished components or bowls.  

There are several ways to minimise the effects of such materials in a pre-treatment process.  Which can include simply draining the tanks, disposing of the solution, then replenishing the water and chemical following a thorough clean down of the inside.  This can have a negative effect on process costs, which includes increased downtime, lost production and chemical usage.

Where a lot of contamination is to be expected TD Finishing can supply ancillary machines to complement their range of pre-treatment systems.


Floating or Sinking

Whether dip or spray contamination can take one of two forms, floating and sinking.  However due to the active nature of the systems, pumped spray in the conveyorised system and pumped agitation in the case of dip pre-treatment, the problem contamination remains in suspension until the system is at rest.  It is here that the problem is most obvious.


Pretreatment Systems

TD Finishing offers three solutions to complement their pretreatment systems and these include;

  1. An oil skimming system for floating contamination
  2. A settlement tank for sinking contamination, and
  3. A combined settlement tank with an oil skimming facility

In all cases, the fluid from the tanks is removed. This is via a diaphragm pump during the process. It is placed into a buffer zone where contaminations are allowed to fall out of suspension. Here it will either float on the surface or sink to the bottom of the tank.  A series of valves and adjustable drains allow for the removal of the contamination to a designated container. Whilst the decontaminated process solution is moved to an outflow tank before being fed under gravity back into the process.


Get in Touch

If you are looking for a solution to your spray pretreatment system maintenance issues or require a more convenient solution to your dip tank contamination removal.  Then why not contact TD Finishing today on 0121 520 8884 or email

We can also assist with full powder coating systems, Demin water units, drying & curing ovens, conveyor systems, overhead gantry cranes and dip tanks.

 If you enjoyed reading this article you may also like to read our previous post on Salt Spray Testing.