Removing varnish in hydraulic oils efficiently

In the last few years, there have been changes to base oils. These changes have led to base oils which are more thermally stable and chemically pure. While in the past the degradation of lubrication oils and hydraulic oils led straight to oil carbon, today there are precursors. These are mostly gel-like substances which lead to brown deposits in "cold" parts of the system. Valves, cylinders and bearings are affected by this. The consequences are higher valve positioning forces, leaking check valves, seal wear on cylinders and increased bearing temperatures in turbine bearings.

That's why there's an increasing focus on the removal of oil degradation products, know as "varnish". We'll explain how you can use oil analysis to detect and effectively combat varnish and avoid unscheduled downtimes caused by oil sludge.

Read more about efficient protection for your system!

4 min reading time

Topics & Products Fluid Engineering Hydraulics

Your system protection for hydraulics & lubrication#OilAnalysis #OilDegradation #SystemAvailability #ConservationOfResources #sustainability

Varnish in hydraulic systems ­& lubrication systems

System protection: why are deposits a problem?#OilSludge #deposits #HydraulicOil #LubricationOil

Oil degradation products in hydraulic systems and lubrication systems can lead to malfunctions and increased bearing temperatures. The result is unscheduled downtime and high costs. Gel-like, resinous or solid oil degradation products are present in the system as residues. They accumulate at different points in the system where deposits on valves lead to increased wear and complete valve failure. Electrostatic discharges accelerate the oil degradation by cracking the oil. The resulting products react chemically to form larger molecules. This oil sludge leads to noticeable system contamination.

Oil analysis: how do I detect varnish in hydraulic oil?#OilAnalysis #MPCTest #antioxidants #oxidation

To detect oil aging products, oil analyses need to be performed. Visual particle sensors, MPC tests and the concentration of antioxidants give an indication of the extent of oil degradation. The main cause for the formation of varnish is oxidation – the reaction between the oil and the oxygen in the air. Furthermore, contaminants in lubrication oil and hydraulic oil accelerate oil degradation– regardless of whether they are solid, liquid or gas. As an expert in fluid conditioning and oil conditioning, HYDAC helps you to control varnish effectively and ensure sustainable plant protection.

Request advice on fluid & oil conditioning

Our solution: HYDAC Varnish EliminationEfficient system protection with the right separation method

Long service lives, low service costs and maintenance costs and high system availability are goals for every system operator. The aim is to minimise varnish and remove it without leaving any residue. Conventional lubrication oil filters and hydraulic oil filters are not particularly well suited to this task. This is because gel-like oil degradation products stick to the surface of the filter medium, blocking its depth structure. Due to the rapidly increasing differential pressure, the filter element service life drops to just a few hours in some cases.

The successful removal of varnish and the associated oil sludge in hydraulic oil can be achieved via a separation process with ion exchangers as well as by reducing the solubility and following this with filtration.

HYDAC Ion eXchange Unit
Removing varnish with ion exchangers

Efficiently remove varnish from phosphate-ester (HFD-R) and polyolester (HFD-U) based fire resistant hydraulic fluids and lubrication fluids with the HYDAC ion exchanger unit.

Our ion exchanger is constructed in a similar way to a bypass filter and works 24/7. The varnish is separated via accumulation onto a specific resin. This enables the varnish to be eliminated reliably. Increase your system's productivity – we're happy to help you.

More information on the HYDAC IXU

HYDAC VarnishElimination Units
Removing varnish with cooling & filtration

For the removal of solid or gel-like oil degradation products: the service-friendly HYDAC VarnishElimination Units VEU are used to condition mineral oils and effectively remove varnish. With this technology, the solubility of the contamination decreases as the oil cools down.

This method is suitable for all lubrication applications and hydraulic oil applications which are operated with mineral oils. Compared to ion exchangers, element changes are possible without complex oil analyses; the higher cost-effectiveness is making the "cooling & filtering" technology increasingly lucrative. HYDAC makes your system protection simple and cost effective.

More information on the HYDAC VEU-F

HYDAC is your partner for sophisticated fluid conditioning solutions

System availability

Increased system availability

Reduce your system failures and increase your system availability with clever varnish removal.

Conservation of resources

Conservation of resources

Extend the service life of your hydraulic oils and fluids and save valuable resources.

Reducing costs

Cost optimisation

Thanks to reduced downtime, extended oil change intervals and increased component service lives, you can optimise your costs in a sustainable way.

Productivity increase

Productivity increase

With efficient fluid conditioning, you can enhance your machine performance and actively protect your system.

Downloads Find more information on our solutions in brochures and data sheets – with our solutions, there's nothing standing in the way of efficient removal of oil degradation products in hydraulic oil.

Let's protect your systems from varnish

Do you want to know how you can best protect your specific system? Discuss your individual requirements with us in a consultation – we'll work with you to find your tailor-made, cost-efficient solution. We look forward to working with you!

Arrange a consultation appointment

More articles on this topic

Electromobility, Fluid Engineering, Mobile Hydraulics
Topics & Products
3 min reading time |

HYDAC fluid conditioning

Find out more about our solution

Electromobility, Fluid Engineering
Topics & Products
4 min reading time |

Technical Cleanliness of Industrial Part Washers

Find out more about our solution

Diesel filtration
Topics & Products
3 min reading time |

HYDAC DieselProtection

Find out more about our solution now