Chemical Technology February 2015

FOCUS ON PLANT MAINTENANCE, HEALTH, SAFETY AND QUALITY

No more fugitive valve emissions

Flexible, reliable, versatile GEMÜVictoria ®

New generation LiveStar live-loading system

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.

GEMÜ 481 Victoria ®

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

For more information contact Rob Waites on tel: +27 11 466-6500, or email rwaites@aesseal.co.za.

17 Chemical Technology • February 2015