Product category:
Fasteners, threaded and non-threaded
News Release from: SKF UK | Subject: Supergrip bolts and dowel pins
Edited by the Engineeringtalk Editorial
Team on 20 February 2003
Getting a grip on coupling bolts
The time saving Supergrip bolt concept from SKF Engineering Products can dramatically cut costs in the mounting and dismounting of large rotating flange couplings.
Maintenance cost efficiency in heavy industries is a make-or-break factor in operational economy The time saving Supergrip bolt concept from SKF Engineering Products can dramatically cut costs in the mounting and dismounting of large rotating flange couplings
This article was originally published on Engineeringtalk on 21 Feb 2001 at 8.00am (UK)
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In some cases, Supergrip bolts have cut remounting times from three hours to three minutes.
Fitted bolts have to be "mauled" into place with a sledge hammer and, even after time-consuming honing of the holes and individual grinding of the bolts, it is hard to achieve an interference fit.
In most cases, there will be a small gap, which may increase with service, resulting in high bolt stresses and vibrations.
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Furthermore, at some point, the bolts will have to be removed and the job will be further complicated by trying to drive out conventional bolts that have seized in the hole due to fretting, overstressing or too tight a fit.
The Supergrip bolts are easily inserted into the hole by hand and expanded to a radial interference fit.
The bolt is then hydraulically tensioned against one nut while the other nut is hand tightened.
For removal, once the tension and expansion pressure has been released, each bolt slides out as easily as it went in.
As well as the tremendous time savings afforded by this system, the coupling halves are held together much more securely, eliminating slippage, and there is no need to worry about the bolts jamming or seizing in the holes.
Maintenance costs are further reduced by the Supergrip bolts being fully interchangeable and able to be used repeatedly, therefore dispensing with the need for a set of spare bolts.
The Supergrip bolts are designed specifically for such high-torque applications as propeller shafts, rudder assemblies, turbo generators, rolling mills and similar applications.
A study released by the Swedish State Power Board showed a 90% reduction in the time required to disassemble and reassemble the couplings of two turbo sets (eight couplings) when using Supergrip bolts.
Similar to the bolts, Supergrip dowel pins can also be used to firmly position machinery and to plug drainpipes or holes in pressure vessels.
The dowel pin is also an excellent solution to plugging holes in nuclear power reactor vessels.
Supergrip dowel pins have already been proven in a reactor vessel during modification programs when the piping connected to the reactor vessel had to be removed. Request a free brochure from SKF UK ...
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