East Hills, NY (May 17, 2005) - - The merits of commonly used conditioning methods to purify fluids in hydraulic and lubrication systems has raised questions about the impact of high heat and vacuum pressure on the chemical and physical properties of the fluid and their performance. A study conducted by Pall Corporation (NYSE: PLL) and Herguth Laboratories, Inc., an independent oil analysis laboratory, to resolve these questions was presented today at the 60th annual meeting of the Society of Tribologists and Lubrication Engineers (STLE). The study examined the impact of vacuum pressure and temperature on water and gas removal, and on the chemical and physical properties of hydraulic and lubricating fluids.
Fluid conditioning or purification is the removal of contaminants such as water and air/gases combined with filtration to remove particulate (solid contaminants) from hydraulic and lubrication oils. It is a relatively straightforward and cost-effective approach to make these fluids suitable for continued use thus extending their service life and reducing the waste stream.
"Fluid conditioning is an essential step to ensure reliability of hydraulic and lubrication systems since it not only enhances the performance of the fluid, but also helps protect system components, resulting in increased productivity and equipment availability" says Kal Farooq, Senior Staff Engineer, Pall Corporation. "Water is one of the most commonplace contaminants due to its ubiquitous nature and ability to ingress into the system. Water may be present in the base fluid in any or all of its three forms: free, emulsified and dissolved, and each can damage the fluid and the system components."
The investigators compared a range of conditioning methods, both mechanical and physio-chemical separation, noting the advantages and disadvantages of each. Centrifuge, coalescer and absorbent filter methods, for example, only remove free and emulsified water and do not remove gases or solvents. Dry air purge, flash distillation-vacuum dehydration and mass transfer?vacuum dehydration methods can each remove all phases of water, gases and solvents. However, dry air purge is a slow process requiring a dry air source and flash distillation-vacuum dehydration results in stress on the fluid whereas mass transfer?vacuum dehydration is gentler on the fluid.
The investigators conducted an experimental analysis using the Pall Model HNP-021 mass transfer purifier to determine its effects on both the additives and the fluid base stock. A series of tests were performed on representative samples of popular hydraulic and turbine lubrication fluids under a range of conditions up to and including extreme vacuum (26"Hg) and temperature (158° F) conditions. These conditions were used to mimic the typical operating conditions inside flash distillation type equipment.
The investigation showed that the reduction in water concentration obtained through the mass transfer process operating at relatively mild conditions of 22"Hg and 113° F were similar to those resulting from the more severe flash distillation type equipment conditions. There was also a 69 percent decrease in the dissolved air content with the mass transfer method.
In conclusion, the investigators found that the conditions used in the mass transfer-vacuum dehydration process is gentler and does not damage the oil, whereas the higher temperature and pressure typical of flash distillation-vacuum dehydration could potentially damage the fluid. The investigation showed that the mass transfer conditioning method had no discernable effect on the antioxidant properties of the two specific fluids evaluated.
"Although the mass transfer method may be somewhat slower in the removal process than those using higher heat and pressure, it does not adversely affect oil performance and is less likely to take out additives," adds Farooq. "These benefits coupled with using less energy translates into both time and cost savings, including increased equipment uptime, improved machine performance, reduced component replacement costs and maintenance of labor costs, lower oil replacement and disposal expense".
About Pall Corporation Pall Corporation is the global leader in the rapidly growing field of filtration, separations and purification. Pall's business is organized around two broad markets: Life Sciences and Industrial. The Company provides leading-edge products to meet the demanding needs of customers in biotechnology, pharmaceuticals, transfusion medicine, semiconductors, water purification, aerospace and broad industrial markets. Total revenues for fiscal 2004 were $1.8 billion. The Company headquarters are in East Hills, New York with extensive operations throughout the world.
Click here to learn about other topics that are being presented at the STLE Annual Conference