The Stone Slinger's Chorus (to the tune of Home on the Range) "Oh give me a home where they need lots of stone Where John Deere and the Cat cannot play Where seldom is heard a discouraging word and the guys spray quite proudly all day"
Maybe you haven't heard of the 'Stone Slinger' ... I certainly hadn't ... but, now that I have, I want one. Take a big shiny Mack, put a projectile launcher on the back and you have a big boy's toy that can do more than the Ancient Greeks thought possible when they designed the first stone catapaults. This machine shoots tons of stone with such accuracy that it can be used in all kinds of ways to make light work of what would previously have been back-breaking labor ... now it's fun! Have a look at this video ...
Achilles Heel? However, the Stone Slinger, like all conveyor systems, relies on bearings to keep its belts turning. Spraying tons of aggregate all day means a lot of grit and dust - and this can lead to accelerated wear for bearings caused by ingress of contamination. As we know, prevention is better than cure, so the savvy stone slingers called in Enviropeel to protect the main drive bearing on one of their systems destined for the 'World of Concrete' show in Las Vegas this year.
James Hardie Inc. is a fiber-cement business employing more
than 2,500 people, generating a revenue of more than $1.5 billion a year.
The James Hardie plant in Pulaski, Virginia produces 1.5
million square feet of fiber board products per day, more than enough for 750
average size US homes. The Company's products are a byword around the world for
cost-effective, high quality building products and it has plants in Australia,
New Zealand and the Philippines.
The cement slurry used for the fiber board wreaks havoc on
the thousands of bearings which the Company uses in the manufacturing process.
With some bearings experiencing failure in as little as 2 weeks, it is not
surprising that Hardie engineers were seeking to find a solution to this
expensive problem. As well as the slurry, epoxy paint sprayed onto the fiber
board as part of the manufacturing process also contaminates hundreds of
bearings.
After contacting Enviropeel USA, a full scale trial
application took place in January which we are confident will deliver the
results the James Hardie reliability engineers are expecting. Enviropeel has
shown a greater than 500% increase in bearing lifetimes in other similar plants
and we expect the same for James Hardie.
The picture top left shows the build up of contamination on production equipment. On the right and below left, examples are shown of the Enviropeel applications that will provide long-term protection for the bearings.
Although one half of the world is enjoying its summer, up here in the northern hemisphere it's still pretty cold and most people are planning what they will be doing once the weather improves. At Enviropeel, the approach of spring means looking forward to the conference season which almost always means a visit to NACE. This year it also means a return to Noria's 'Reliable Plant' Exhibition, which Ivan attended last year, with great success. As luck, or Murphy's law would have it, both exhibitions are in the same month and on the same dates, so, while it makes the dates easy to remember, it makes the logistics much harder. NACE is slightly longer, starting on the 15th April, Reliable Plant starts on the 17th but they both finish on the 19th. If you would like to visit us, you would be very welcome either in Phoenix for NACE or Indianapolis for Reliable Plant. Look forward to seeing you!
Historians will know that when George Washington introduced
the concept that 'many mickles make a muckle', he was referring to the old
Scottish saying, 'mony a mickle maks a muckle' which essentially means that
many small things add up to one big thing. For the Scots, they were talking
about taking care of the pennies and the pounds would take care of themselves,
but it is a saying that resonates in many areas, including modern industrial
infrastructure. It is all constructed from many small things, creating
machinery and plant that depends on the proper function of its smallest
component.
A wind turbine, for example, is a collection of 'mickles'
all of which make a pretty large 'muckle' ... stuck in the middle of nowhere
and specifically designed to be exposed to the worst weather on the planet.
A
lot is written about the design and maintenance of turbine components ...
products to reduce wear and tear in the gears, how to control the atmosphere in
the nacelle and tower to minimize corrosion, coating systems for the structure
and blades ... the list of ASTM and ISO standards that apply to the design and
manufacture of these complex structures is much longer than my arm.
But one
thing appears to be missing ...
... anchor bolt maintenance standards and recommendations
... see if you can find any.
Turbine foundations are a big deal. A standard 1.5 megawatt
wind turbine tower is well over 200 feet high (with its blades making it more
than 320 feet), supporting a combined weight of 56 tons for the nacelle and 36
tons for the blade assembly. The tower itself weighs around 70 tons. All of
this is anchored to its foundation by a series of bolts set in concrete ...
quite a lot of concrete. Have a look at this video of a foundation being constructed
in Oregon. You can see the ring of anchor bolts being embedded in the enormous
circle of concrete. Once the foundation is complete, the first section of the
tower is lowered on to the bolts and secured, then the rest of the turbine is
assembled above.
The bolts have to be tensioned accurately to prevent any
movement on the base when the tower flexes in the strong winds it is designed
for, but still allow some stretch to reduce foundation deflections from the
high wind loadings. So the condition of the bolts and nuts is critical to the
long-term survival of the tower. Bolt tension issues have been identified as a
cause for failure in turbine collapses as have bolt failures from the effects
of corrosion.
Yet many bolts are left exposed to the elements, with the
result that corrosion rapidly occurs. Proprietary solutions exist for
post-construction remediation of corrosion damage to exposed bolts ... these
include tape wraps, grease and bolt caps ... but all suffer from limitations
that require frequent maintenance or replacement to prevent corrosion damage to
the turbine anchors. If the nuts and threads corrode, they cannot be
retensioned properly.
So the entire turbine structure relies on a few relatively
small nuts to ensure it is firmly fixed to the anchor bolts, yet it is left to
the operator to ensure they get the protection they need.
We think protection of these nuts is pretty important.
Turbine towers do not collapse very frequently and, because they tend to be off
the beaten track, injuries from such collapses are rare but the cost of
replacement runs into millions and the constant vigilance that is required to
maintain the bolts is wasteful and unnecessary.
The Enviropeel solution is simple. Anchor bolts can vary in
length but the exposed threads are always several inches long, so providing the
correct size of bolt cap can be a problem. Because Enviropeel bolt applications
will fit any size or shape of bolt, it provides a straightforward, one-size
fits all solution ... but this is not its only advantage over bolt caps. Bolt
caps have to stay in position to work, they usually have some kind of friction
fit mechanism to maintain their seal with the base but this is not always
effective. Because Enviropeel is spray applied, it moulds itself around every
thread making it impossible to dislodge yet easy to remove, if required, by
simply screwing it off.
And, of course, Enviropeel contains its own active
inhibitors so, if corrosion is already present in the bolts, it not only
prevents further deterioration but it will also condition the nuts and threads
so that they can easily be adjusted for maintenance. Compare this with
protection using a wrapping system ... as long as the wrap stays intact, it
will provide a barrier to water ingress but nothing else. And, it cannot be
removed for inspection without having to be completely replaced whereas, with
Enviropeel, it can be removed and replaced.
Contact Enviropeel for information on how we can design the
best possible corrosion protection system for your specific application. We
would love to hear from you.
A short video of an Enviropeel wind turbine application can
be viewed below.
