Page 14 - Energize October 2021

NEWS

Flameproof cable glands with game-changing features

new range of flameproof cable glands The main features of the different versions
from Pratley allows for soft-bedding in the Pratley Taper-Tech Flameproof Cable
c
A ables like PVC and the like, which Gland range are as follows:
are prone to creep, to be fitted to flameproof • Pratley Taper-Tech Flameproof Double
equipment without any concern regarding Compression Gland for armoured and
cable damage or poor long-term sealing. braided cable
The Pratley Taper-Tech flameproof gland • Flameproof double compression gland for
range consists of four separate glands in both SWA and braided cables
two unique categories. First is the Pratley • Complete with unique Taper-Tech flame
Taper-Tech gland for armoured and braided seal technology
cable. This is a ‘double compression’ gland, • Fully certified to both SANS and IECEx
meaning it has both an inner and an outer Standards
seal. The second is the Pratley Taper-Tech against extremely high explosion pressures, • Quad certified Ex d/e/nR and t, for Fiery
single-seal flameproof gland, also for which in many cases may be as high as 30 Mines and Surface applications
armoured and braided cable, but with a bar. For the seal to function properly, there • IP66/68 tested to 350 m continuous
durable rubber shroud. must be adequate pressure between the seal • Continuous operation at -35 to 120˚C
The range also includes two ‘double and the gland bedding. • Patented cable safety gauge
compression’ glands for unarmoured cable, “Imagine the explosive gases travelling • Red Ex band, for easy identification in
one being a hose-tail version that features down the cable and pressing against this the field.
a spigot on the compression nut. This is seal. This seal is now being pressed on its
intended to be fitted with flexible hosing, taper which, due to the taper action, forces Pratley Taper-Tech Flameproof Double
for example, where cables are fitted to the bush to press down onto the cable, Compression Gland for armoured and
mining machines, for protecting the cable increasing the seal force. As the pressure braided cable with a shroud
outer sheath. rises, the contact pressure between the bush • Flameproof gland for both SWA and
The unique feature of this flameproof and the cable increases proportionally. Even braided cables with a durable UV resistant
cable gland range is that all versions are if you increase the pressure to 40 or 50 bar, rubber shroud
fitted with Pratley Taper-Tech flame seal the seal will accommodate that pressure by • Complete with unique Taper-Tech flame
technology, consisting of tapered seals further closing onto the cable. Once that seal technology
made from superior, Pratley developed, pressure is released, the bush will relax • Fully certified to both SANS and IECEx
high temperature and low compression-set again, and reduce the contact pressure on Standards
elastomers. The seals all have a taper on the the cable,” Breedt says. • Quad certified Ex d/e/nR and t, for Fiery
leading edge that abuts against the gland As the leading edge of the seal forms Mines and Surface applications
nipple taper on the inside. The taper on the a taper in the direction of the applied • IP66/68 tested to 350 m continuous
bush and the one on the cable gland’s nipple explosive pressure, when this applied • Continuous operation at -35 to 120˚C
are angled differently. pressure increases so too does the contact • Patented cable safety gauge
This means that, under thrust or radial seal pressure on the cable bedding. • Red Ex band, for easy identification in
pressure from the front, when it is tightened, Once the pressure is relieved, the bush the field.
this differential taper allows the bush to returns to its initial low-pressure state, so
slide down the taper easily, reducing the the high seal pressure is only on the cable Pratley Taper-Tech Flameproof Double
force needed to achieve radial compression. when it is needed. Compress Gland for circular unarmoured cable
“In other words, less torque to reduce The same technology is amplified in the • Flameproof double compression gland for
the diameter of the bush,” explains Sven cable gland for unarmoured cable, which circular unarmoured cables
Breedt, the company’s electrical research & not only has to seal against high explosion • Complete with two unique Taper-Tech
development manager. pressures, but also retain the cable axially sealing technology seals
A major benefit of this technology is against pull-out forces. “This is achieved in • Fully certified to both SANS and IECEx
low initial radial pressure or a small amount a similar manner to that used for sealing, Standards
of contact pressure on the cable. This is however, the rear outer seal has a taper • Quad certified Ex d/e/nR and t for Fiery
important because most cables in the which is in the direction of the cable pull- Mines and Surface applications
field are made from PVC, which exhibits force. This too increases proportionally to the • IP66/68 tested to 350 m continuous
‘cold flow’, meaning the relaxation of the pull-force on the cable, meaning that high • Continuous operation at -35 to 120˚C
cable bedding over time. “This can be contact pressures are only present on the • Patented cable safety gauge
dangerous for both the flameproof sealing cable when it is being pulled on. Taper-Tech • Red Ex band, for easy identification in
properties of the termination, as well as the completely negates cable damage usually the field.
secureness of the cable to the equipment,” experienced with subpar weak-back seals,
Breedt explains. while complying 100% to the stringent IECEx Contact Sales, Pratley,
Flameproof cable glands fitted to flameproof cable gland requirements,” Phone 011 955-2190, sales@pratley.co.za,
flameproof equipment are intended to seal concludes Breedt. www.pratleyelectrical.com

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