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High Tech Adhesives
and Composites Innovative manufacturers of high-performance bicycles and accessories such as handlebars, bar ends and seat posts are turning to state-of-the-art adhesives to produce durable joints on substrates including aluminum, titanium and fiber composites. The AralditeŽ adhesives are supplied by Vantico, a pioneer in producing epoxy, polyurethane and methacrylate structural adhesives for transportation, appliance, recreation and general manufacturing industries. Adhesives selection is an essential aspect of bike and component assembly. The materials must bond a variety of substrates with dissimilar coefficients of thermal expansion (CTE) and produce joints strong enough to withstand exposure to vibration, temperature extremes and corrosive substances such as salt spray. To satisfy these diverse requirements, LP Composites relies on Araldite 2015 epoxy to build ergonomically improved bar ends, grips and seat posts for mountain and road bikes. Before specifying the high-performance Vantico paste, LP investigated a number of adhesives from different manufacturers. Technicians found that the Araldite 2015 provided the handling ease and physical properties needed to securely join braided carbon/aramid fiber components to aluminum alloy end-fittings used in bike accessories. Similarly, Serotta Bicycles assembles its Ottrott ST custom bikes with toughened epoxy from Vantico. The adhesive is used to install carbon fiber tubes in polished titanium lugs, producing lightweight bikes that combine speed with comfort and responsiveness. Process Both bike manufacturers begin with pre-formed components. At LP, carbon and aramid fiber bike accessories are resin transfer moulded and then cured. The process provides precise control of composite wall thickness, optimizing strength and flex characteristics for outstanding riding performance. The resulting parts, available in black, natural carbon and hybrid carbon-and-gold braid, are also aesthetically attractive with "high-tech" appeal. Sue Fisher, president of LP says, "We've come to rely on advanced composites and adhesives to build anatomically designed, extremely tough grips, handle bars and seat posts. The Araldite 2015 epoxy is easy to use because it's gap filling and sag resistant. It's also ideal for securely joining the dissimilar materials we use in fabricating bike accessories." Araldite 2015 epoxy attains handling strength after four hours at room temperature and produces joints with lap shear strength of 3,200 psi at room temperature. At Serotta, carbon fiber tubes and titanium fitting are pre-welded and substrate surfaces are abraded to ensure good adhesion. The epoxy, that is supplied in convenient dual-barrel cartridges, is mixed and dispensed through a disposable nozzle onto a board. The adhesive is then applied to the metal and composite surfaces using a tongue depressor. Next, carbon fiber tubes are inserted into the metal fittings until fully seated. Excess adhesive is removed, and the bonded frame is cured overnight in the prepared assembly jig. "We manufacture each bike with a custom-designed geometry using a specially designed fixture that allows us to construct each frame according to pre-established dimensions. The Vantico epoxy helps us in this process because it is easy to dispense from waste-free 50 ml cartridges and features the needed combination of tough physical characteristics for durable bonding," according to Jason Clark, R&D Director at Serotta. Vantico's high-performance epoxy is designed for performance at temperatures from 88.6°C up to 121°C and exhibits a room-temperature lap shear strength of 2,500 psi. "Bicycling is all about movement. Cycling enthusiasts rely on high-performance equipment that will support their continuous motion on a variety of terrains and in changeable weather conditions and temperatures. Composite parts joined with advanced epoxies help us produce bikes that have the power, endurance, speed and comfort our customers demand," Clark concludes. Vantico Inc.
Rotary Screws
Compressors Three Sullair LS32 300 horsepower rotary screw compressors have been providing air for instrumentation and paper machine operations for over 23 years at the Bowater Incorporated newsprint mill in Dalhousie, New Brunswick. A fourth Sullair TS32 400 horsepower unit recently completed over 14 years of service before a routine overhaul. The mill performs regular service on the four units through a scheduled maintenance program administered by the local Sullair Distributor, Atlantic Compressed Air Limited of Moncton. Sullair
Desiccant Breather Filters
Maximize Equipment Life It's doubtful that anyone working in less than pristine surroundings -- such as a medical research 'clean room' -- would be surprised to learn particle contaminants cause lubricant and hydraulic system deterioration. What might surprise some, though, is that many experts consider moisture accumulation in lubrication oil a chemical contaminant, which can be even more destructive than particle contamination. As with particle control, maintenance personnel must take care to minimize entry of moisture in order to curtail damage within engines, turbines, or gearboxes in order to prevent downtime, the expense of labour, and having to replace oil and damaged parts. One of the most cost-effective ways to prevent contaminants -- particle or moisture -- from entering machinery is with a number of different kinds of breathers, including oil coalescing, expansion chamber/bladder, desiccant, and hybrids. Finding the right breather for the right application is the first maintenance consideration when attempting to extend a system's life. Of late, many OEMs have chosen to use desiccant breathers to accomplish this on their products. Removing Moisture Expands Oil and Equipment Life Every manufacturing industry creates its own internal environment, resulting in contamination peculiar to that industry, which, in turn, requires specific breathers. Desiccant breathers, either by themselves or in combination with other types of breathers, are particularly useful in environments that contain high humidity levels, as well as dust. There are a number of ways that contaminants can enter equipment, including poor oil sampling, improper handling practices, inadequate seals, and poorly maintained, or the lack of filter breathers. The abrasive, pitting effects that particles have on engines, turbines, or gearboxes is obvious. But perhaps less understood are the effects water has on moving parts. Despite all the attention and the million of dollars spent to improve particle-contamination filtration technology that has reduced failure rates by as much as 90%, water can be a far greater danger. Water exists in oil in three stages. Water molecules dispersed throughout oil are in a dissolved state, which can be as much as 200 ppm to 600 ppm. And the older the oil, the more water it can hold. Then, when the water exceeds the maximum level that the oil can remain dissolved, the oil becomes saturated, and the water exists as suspended emulsion droplets, resembling fog. As the amount of emulsified water and oil increases, a layer of free water is produced, which settles to the bottom of tanks and sumps. Once water is mixed with oil, a host of chemical reactions, or hydrolysis, begins to take place as it attacks oxidation and rust inhibitors, viscosity improvers, and the oil's base stock. Water can accelerate the oil's age rate tenfold. These attacks result in varnish, sludge, organic, and inorganic acids, surface deposits, and polymerization (a thickening of the lubricant). As little as one percent contamination can reduce bearing life by as much as 90%. The implosion of water vapour can produce honey-comb pitting on bearing surfaces. How Desiccant Breathers Work Even though the basic concept for desiccant breathers has been the same for over 20 years, they have evolved into numerous products that can handle a multitude of applications. Comprised of a hygroscopic agent, silica gel that can attract and retain up to 40% of its weight in water - and a synthetic filter media, desiccant breathers are an important element in any preventative maintenance program. They are designed to prevent moisture and particulate contaminants from entering fluid reservoirs as pressures occur through thermal expansion and contraction of the fluid, or during filling and emptying, as they help hold down sludge deposits and water-contaminated oil. With the addition of carbon (to the silica gel), desiccant breathers can capture oil mist and evenly disperse incoming air to ensure efficient use of the synthetic filter in combination with the silica gel. As the air passes through the synthetic filter, ideally, it will retain all particulate matter down to three microns, and 70% or more of particulate matter down to 0.5 microns. As the air passes through the silica gel the moisture is absorbed. A second filter can give added protection, as clean, dry air continues to flow through the breather vent, and then the air passes again back through the silica gel, partially regenerating it, thus extending the life of the breather. By capturing the oil mist, the breather drastically reduces pollution in the work environment. If the breather is designed with more vent holes to allow variable airflow patterns, the filtration media and the desiccant's drying properties will be substantially increased. This simple design allows the desiccant breather to be more efficient, and reduces the amount of desiccant gel that each breather must contain. Of particular use in applications where there are minimal volume changes and the environment is both damp and dirty, the newer expansion-type breathers can control the breathing and permit expansion and contraction of the airspace. It is simple to know when to change desiccant breathers because manufacturers have added dyes to the silica gel that changes colours as the gel becomes saturated. When choosing the size of the desiccant breather, consideration should be given to the amount of air exchanged (the required cubic feet per minute) for each application. Airflow and the flow of liquid must match, or surpass the tank's fill and drawdown rate. As the flow rates increase, so should the size of the desiccant breather. It might be a wise move to consult with the breather manufacturer when trying to determine the correct size for your application. Also, there is a need to consider the operating environment when choosing which breather housing (steel or plastic) to use. While the plastic housing can be sufficient for many industrial settings, steel housings are particularly applicable in hot, dirty environments. A few suggested applications for desiccant breather filters include: * stationary and mobile hydraulic
systems Conclusion Desiccant breathers are powerful preventive maintenance tools that can protect untold numbers of industrial and commercial equipment, yet they are only as good as the entire contamination control and maintenance practices used in conjunction with them. Proper sampling techniques, the use of the correct seals, and the appropriate lubricant storage and disposal systems all come to play along with desiccant breathers in preventing lubricant contamination. In this way, you can maximize machine and lubricant life, while you minimize capital and operating expenses that will assure the greatest return on investment. Chevron Products Company
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Canadian Industrial Equipment News July/August 2005 |
May 16, 2008
LP
Composites uses Araldite 2015 epoxy adhesive to bond braided composite
components into metal fittings in fabricating bike bar ends, grips and
seat posts.
Mixed
Araldite epoxy is applied to bike frame components using a tongue
depressor.
Serotta
Ottrott ST bikes are known for their performance among cycling
enthusiasts.
At
right, Tom Bourgeois from Sullair's Distributor Atlantic Compressed
Air Limited. At left, Roger Daigle Energy Management from Bowater
Incorporated.
