sensors & systems - Industrial Technology Magazine

ELECTRICAL EQUIPMENT & DESIGN
Enclosures, Cabinets & Fans
Cost-effective
water proofing
Why buy a sarcophagus when all you really need is a plain box?
Gel filling offers an alternative to bespoke design when you’re
looking for long-lasting performance in tough, wet conditions
Anyone who has had the responsibility of
specifying enclosures for use in hostile
environments or buying purpose built IP68
underwater enclosures to fulfil their specific
requirements will know that it can be a very expensive
and time consuming exercise. A whole host of specialist
companies will tell you that they have designed and
developed their particular range of products and that
they have supplied enclosures for permanent submersion
in up to 30 - 50 plus metres of water and can therefore
provide you with a satisfactory solution to your enclosure
problems.
Sure they can – at a premium price. And then there
are the ‘must have’ accessories. The specialist intricate
gaskets and the matching cable glands and grommets,
without which the entire enclosure is rendered useless.
But now there are cheaper options, in the form of gel
filling systems. We found solutions from both GH Lucas
and Spelsberg in the UK.
Already in wide use throughout Europe, the GH
Lucas solution consists of an incredibly fast, crosslinking
bi-component formula that is presented in two
options. On the one hand, you can have the two
components correctly proportioned into pouches, that
are separated by a divider. Or alternatively, the product is
offered in a two-bottle pack, together with a measuring
vessel and mixing spoon to offer the user a no waste,
quick, clean and efficient method of mixing and pouring.
Simply pour the liquid into your standard enclosure and
within 10 minutes of pouring, the mixture will be
completely cross-linked and ready for use.
The cross-linked material is characterised by strong
binding forces that will not flow on exposure to heat, as
the links between the molecular chains holds the chains
together. Beyond a certain temperature, called the
crystalline melting temperature, the crystals disappear
and the material becomes soft and malleable.
Wide ranging applications
GH Lucas can demonstrate a host of successful uses for
its gel-system solution, including enclosures for
underground street lighting controls, mounted in sewer
systems, in harbours with cameras inside to monitor fish
stocks, on ROVs, in pits and water treatment plants, on
pumping systems, on reservoirs, on rivers and on flood
plain areas, transport systems, roadside monitoring
equipment and other places where electrical equipment
and other apparatus needs to be protected from
condensation and
water ingress, and with the possibility of being totally
submerged underwater. In fact, according to the
company, the deeper the gel-filled application is
submerged, the more the natural water pressure
increases the effectiveness of ingress protection, which is
quite the opposite with traditional resin fill devices, as
increased water pressure has been known to crack the
resin in-fill at greater submerged depths. Further, the
system is chemically inert and non-toxic, and therefore
totally safe.
For its part, Spelsberg ELS UK has launched its new
Abox GT range of extreme environment electrical
enclosures which can also make use of an extremely
durable and easy to use gel-fill system to protect
electrical connections, even after prolonged exposure to
water, soil, sand or grit. The IP68-rated enclosure
system will even withstand extended periods of total
immersion. Abox GT enclosures are ideal for any
application where electrical connections must be
protected from the wet. Typical uses are in flood prone
areas, washing installations, tunnels, docks and
agricultural or horticultural applications.
Spelsberg uses a semi-setting gel compound to
protect the contents of the box after assembly. As with
the GH Lucas solution, the gel is a two-part mixture
designed for easy mixing and installation in the toughest
site conditions. A handy mixer bag included with every
box can be used to prepare and insert exactly the right
amount of gel. Once cured, the gel-filled enclosures are
shock and fracture-proof, UV-resistant and exhibit low
flammability.
Unlike foam based systems where the foam is
extremely difficult to remove after it has been inserted,
the clear Spelsberg Abox GT gel can easily be removed
without damaging the enclosure or the connections
allowing for simple rewiring or reuse.
The Abox GT range is available in four sizes from
80x80x52mm to 140x140x79mm. The enclosures will
handle cable cross sections from 1.5 to 10mm 2 . In tests,
they withstand immersion in water to a depth of 15m for
168 hours. The new enclosures join the largest range of
plastic enclosures available ex-stock in the UK from the
company's Telford headquarters; centrally located to
provide immediate access to technical support and
next day delivery on all standard items.
MORE INFORMATION:
GH Lucas: enter D265 on the enquiry card
Spelsberg ELS UK: enter D266 on the enquiry card
Or visit www.industrialtechnology.co.uk
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INDUSTRIAL TECHNOLOGY • May 2008