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Chemical Technology • February 2015
FOCUS ON PLANT MAINTENANCE, HEALTH, SAFETY AND QUALITY
Flexible, reliable, versatile GEMÜVictoria ® Elastomer seated butterfly valve: • Improved tightness thanks to special design of liner - even in case of big diameters • All-purpose applications by versatile material choice • Modular structure • Low torque values • All food- and drinking water approvals GEMÜ VALVES AFRICA (PTY) LTD Stand 379, Northlands Business Park Hoogland Ext. 45 Northriding, Randburg Phone: (0)11 462 77 95 info@gemue.co.za www. gemu-group .com GEMÜ 481 Victoria ®No more fugitive valve emissions
Valve live-loading systems are complicated. Most require the use of
torque-measuring tools and incorporate a disc spring stack that is
often too long for the available bolt length. As a result, valve bolts
usually need replacing.
Now, British multinational AESSEAL has launched LiveStar, a
new-generation live loading system designed to be compact without
requiring extra bolt length to accommodate the uncompressed disc
spring stack.
LiveStar has been designed as an encapsulated disc spring con-
figuration with defined compression length to automatically adjust
the gland and maintain constant pressure on the valve packing
set. It is likely to find a major market in control valves installed in
environmentally sensitive applications such as those found in pet-
rochemical refineries.
The system fits on existing gland bolts and is tightened on instal-
lation until the visible assembly gap closes. During operation, this
closed gap serves as an indicator of valve packing wear or consolida-
tion, either or which will cause the gap to reappear, whereupon the
assembly is simply retightened to its optimal set point. No torque
wrench is required.
A major advantage of the AESSEAL design over other live-loading
systems, according to a recent report, is that the disc spring, which
is encapsulated against environmental impact by an outer cylinder,
slides on an even, machined surface rather than on a bolt thread.
The disc spring can therefore never become over-compressed, hang
up on threads or shift asymmetrically on the bolt.
Further, LiveStar needs no new bolts fitted to the valve to accom-
modate the system. The extended nut is screwed onto the existing
valve bolt. Other features include compensation for thermal expan-
sion of the valve and flange parts, optimum and pre-determined
compression set by the dimension of the spring housing, protection
of the spring set from dirt and outside contaminants, and sustained
maintenance of a constant gland load and sealing force.
Available for all standard metric bolt diameters from 8 mm to
27 mm and Imperial UNC from 5/16” to 1”, the complete LiveStar
range can be sourced from AESSEAL branches and distributors
throughout Africa.
For more information contact
Rob Waites on tel: +27 11 466-6500, or
New generation LiveStar
live-loading system