Our former managing director was contacted by the property manager of an apartment building with a hydraulic elevator. After 23 years of operation, the service company recommended analysing the oil and replacing it depending on the results. Because of the quoted cost and lead time, Mr Friess decided to investigate the oil himself.
Using a FRIESS inspection kit, he found a high concentration of oxidation products and a moderate level of particle contamination.
The elevator used HLPD hydraulic oil. Unlike standard HLP oil, it contains additional detergent and dispersant additives that keep dirt and water suspended to protect the system. This oil type is often used in mobile hydraulics or systems exposed to strong temperature fluctuations, preventing water from settling and helping bind dirt particles for filtration.
These additives usually increase the oil’s electrical conductivity. Fresh HLPD oils are therefore often unsuitable for FRIESS electrostatic oil cleaning systems, which require an electrically insulating fluid.
After 23 years in service, much of the detergent additive had already reacted, so a FRIESS EFR system could be used. An EFR D2 electrostatic oil cleaner was moved into the basement and connected to the elevator’s 450-litre hydraulic system.
After approximately 750 hours of cleaning, a new oil analysis showed a major improvement:
With the old oil restored to an almost new condition, the elevator is expected to operate for many more years using the same oil charge. This is the best solution from both an environmental and economic perspective, and it avoided the long lead time associated with an oil-change service appointment.
