Tuesday, 31 May 2016

How Manufacturers Treat Humidity In Hydraulic Cylinder Oil?

If you have ever used hydraulic equipment for any length of time, you must have faced issues related to hydraulic oil. Hydraulic cylinders manufacturers will explain how to deal with humidity content in hydraulic oil. Oil becomes cloudy when water enters into it above its saturation level. This saturation level is the water quantity that can dilute in the oil’s molecular chemistry and is usually 200-300 ppm at 68 degrees F or 20 degrees Celsius for mineral hydraulic oil. You must understand that if hydraulic oil is contaminated, it will look cloudy and that shows a minimum of 200-300 ppm of water is present or mixed into the oil.


If hydraulic oil gets contaminated with water, the quality degrades and entire system gets affected. Number of negative effects made by humidity on hydraulic oil are-
  • Eliminates some additives and reacts with others to create corrosive by-products that further attack some metals.
  • Lowers lubricating film-strength. This affects the surfaces and makes them wear and corrode. 
  • Makes filters inefficient by clogging them.
  • Increases ability of air activity
  • Increases the chance of cavitation

How to remove free and emulsified water?

There are three types of methods that hydraulic cylinder manufacturers use for eliminating free and emulsified water.
  1. Polymeric filters 
  2. Vacuum distillation 
  3. Head space dehumidification 

  • Polymeric filters – These types of filters look like conventional particulate filters. Water leads to swelling in the polymer, which traps the water inside the media. These filters are ideal for eliminating small amount of water content.
  • Vacuum distillation – it is a technique that includes a combination of heat and vacuum. The technique helps in elimination of water at a temperature that doesn’t put impact or damage the oil or its additives.
  • Head space dehumidification – This is a method that includes circulating and dehumidifying air from the reservoir head space. Water present in the oil migrates to the dry air in the head space and is constantly removed with the help of dehumidifier.
Like all other things behind contamination, preventing water ingress is affordable than removal from the oil. A main point of water ingression is via the reservoir head space. Several hydraulic system reservoirs are equipped with breather caps. These caps are responsible for moisture entering to the reservoir as the volume of oil changes through either thermal expansion and contraction, or the actuation of cylinders.

When you replace the standard breather cap with a hygroscopic breather, it will eliminate the moisture ingression and particles via the vent of reservoir. These breathers combine a woven-polyester media that helps in filtering the particles as small as 3 microns, with silica gel desiccant to expel water vapor from incoming air.

You can ask for professional assistance to perform these techniques from hydraulic cylinders manufacturers. They are right people who know all the tactics of eliminating water from hydraulic oil. For further queries, contact Liner sleeves. Share your requirement with them and get a quote.