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Customised Seals and Sealing Packages
High Speed & High misalignment Lip Seals
Lip Seals, Face Seals and packings
Laser Surface Texturing and long life Mechanical seals
Laser Surface Texturing – LST
A Revolution in sealing Technology
Laser Surface Texturing or LST developed by Surface Technologies has successfully resolved some of the severest mechanical seal performance problems and is now available as an integral part of these high performance seals. This unique treatment designed to overcome the effects of marginal lubrication has shown it can help combat the most common causes of seal failure such as dry running, media vaporisation and contamination.
LST generates high precision micro pores or dimples, usually in the face of the stationary ring, that are optimised to trap scarce lubricant whatever the medium. Each pore acts as a micro-hydrodynamic bearing generating an improved lubricant film and pressure differential. Face friction can be more than halved with corresponding reductions in face temperature. Typically LST can more than double seal life in poorly performing applications, or if seal life is not an issue it can greatly enhance security against unforeseen operating conditions such as loss of media flow or sudden pressure peaks.
Actual mechanical seal costs represent a very small part of the total cost of failure. Of far greater significance are the costs of lost output from highly automated process plants and any knock on effects with other critical equipment. LST therefore offers huge potential savings to all users of pumping equipment particularly when average seal lives or MTBF (Mean Time Between Failure) can be less than one year as recently quoted by one of Europe's leading chemical producers.
LST Concept
This technology is based on a pulsating laser beam that, by a material ablation process, generates thousands of micro pores or dimples in one of the mating surfaces. All parameters are highly controlled and can be optimised for each application if required.
Typically the density of micro-pores is 50% of the surface area
LST Advantages
Reduces metal to metal contact Could facilitate speed / performance increase Reduces friction by up 75% Wear resistance can be increased 6 fold in extreme cases Improves component life & reliability Longer life in lubricant starvation situations Improves seizures resistance 2 fold Reduces power consumption Allows increased service periods or down sizing Reduces maintenance costs Helps prevent catastrophic failures Heat generation can be reduced by 30% Could pay for itself in a few weeks Application Successes
Improved mechanical seal life 4 fold to in excess of 10,000 hrs. in oil refinery aromatic liquid pumps. $900 per annum saving in maintenance cost alone. Increased life of navy Corvettes fire fighting pump seals 3 fold. All pumps now specify LST of seals and navy looking to improve reliability of piston rings in IC engines. Initial tests by two major auto manufacturers suggest a 30 to 50% reduction in piston ring friction with LST and 1 to 2% increase in engine power output. Improved seal lives of river water pumps from an average of 3 weeks to over 6 months. Mechanical seals in Lobe pumps handling cosmetic & personal care products failed in just a few days or weeks due to evaporation & solidification of media. LST extended lives to in excess of one year. The following photographs depict failed untreated carbon on WC seal rings (on the left) after 400 hours of operation. LST treated rings can be seen on the right and show minimal wear after 550 hours. They eventually ran for several times this life.
Other Possible Applications
Mechanical seals Duo-cone Seals Roller bearing thrust ribs Thrust Bearings Thrust collars/washers Water pump seals Plain & hydrodynamic bearings Piston rings & other engine components Surfaces lubricated by water or non flammable solutions High temperature surfaces lubricated by ATF or other low viscosity lubricants Gas Seals in turbines Helps reduce fretting corrosion LST can help prevent or minimise the most common causes of mechanical seal failure
Wear due to frequent start-ups Fluctuations in process pressure Abrasive media Fluid vaporizes or exceeds flash point Fluid attacks / corrodes / degrades seal components Cavitation breaks up faces Mixed lubrication Debris builds up around seal Media crystallisation Dry running New
Surface Technologies has launched 6 different designs of mechanical seals all with LST as an integral part of their manufacture. Produced from the highest quality corrosion resistant materials the designs and sizes are estimated to cover over 60% of all unbalanced seals in common use today. These are now available from Advanced Sealing Solutions Ltd.
The following seal types represent a high proportion of seals in use today. If however they do not include the sizes or designs usually specified for your equipment we can treat used or new seal rings from your existing seals upon request.
LST – 100
A general-purpose seal comprising an elastomeric bellows and single spring loaded face. Available in various materials, sizes range from 12 to 80 mm shaft size.
LST – 110
Single conical spring general-purpose design with higher temperature capability than LS – 100 Available in various materials, sizes varying from 16 to 75 mm shaft size.
LST – 120
A further single spring general purpose design but with higher operating temperature capabilities up to 200° C. Compact design available in various materials including Sic/Sic to suit shafts from 12 to 60 mm diameter.
LST – 150
A single spring cartridge design with good anti -clogging characteristics suitable for light chemical duties and operating temperatures up to 200° C depending upon materials specified. Sizes available to suit shafts from 18 to 80 mm diameter.
LST – 210
Designed for extremely corrosive environments this cartridge design utilizes Sic and PTFE materials capable of operating at temperatures up to 250° C. Available from 25.4 to 53 mm shaft sizes.
LST – 290
This compact multi- spring cartridge design offers the ultimate performance in highly corrosive environments and temperatures ranging from –50 to + 250° C. Again based on Sic faces and PTFE materials sizes are available for shafts from 20 to 70 mm.
Treatment of competitors or bespoke Seal Rings
We are happy to treat the faces of your existing seal rings. Used or worn rings may need lapping prior to treatment, but prototype or small quantities can usually be treated in two working weeks. Stocks of treated rings could be held by Advanced Sealing Solutions subject to agreement and supplied on a JIT basis.
In particularly demanding or problematical applications, the LST treatment can be optimised to maximise the performance improvements.
