The story of the 40-something year old Neles butterfly valve series began back in 1973, when the co-founder of Neles Oy, Antti Nelimarkka, asked his team to finalise a sketch he had drawn in his legendary notebook. The challenge had been to develop a butterfly valve that could withstand temperatures up to 600°C and still maintain excellent tightness characteristics and durability. As it was something that had never been done before, it was the perfect challenge for an innovative company such as Neles.
The first of its kind
From the very beginning, it was clear that only a metal seated valve could work in such conditions. However, no such designs had been developed before. After two years of development, the Neles R&D team came up with something that is known today as the Neldisc valve. The U-shaped metal seat and elliptic disc formed a unique triple offset valve design, seen in many butterfly valve products today. At the time, it was a first.
Initial deliveries at the end of 1975 exceeded all expectations and the valves were discovered to be bubble-tight, even in high temperature conditions. The product contained many construction and manufacturing technology innovations, and, by the end of the development, intellectual property right protection had been gained in 13 different countries for the revolutionary elliptical disc design with the metallic seat ring.
New applications discovered throughout the years
Initially, the target market included the refining, chemical, petrochemical and other process industries. Later on, in order to expand to liquefied natural gas applications, a low-temperature cryogenic, high-performance butterfly valve was developed in 1982. Many other prominent possibilities for this highly versatile product were discovered over time. In the early ‘80s it was realised that butterfly valves are excellent for control applications, as there is no seat friction in the control range at all and the rangeability of the valve is surprisingly high.
To overcome the last true challenge in control applications, the high dynamic torque in big opening angles, S-Disc noise abatement technology was developed and patented in the mid ‘80s. The same technology, which is still a top-notch feature today, also enables the elimination of cavitation and reduces the overall noise of the valve. Further doors were opened by the realisation that the butterfly valve could be closed much faster than other corresponding quarter-turn valves, such as ball valves, offering excellent performance in ESD and other on-off applications.
Today’s full product portfolio
Today, the Neldisc product family has many members and is available in all major end designs (L6 double flanged, L1 and LW as wafer, L2 and LG as lug) in the most usual pressure ranges and with many options for demanding applications requiring high-cycling resistance, steam jacketing, erosion resistance and so on.
“In the past 40 years, we have supplied more than 700 000 Neldisc valves all over the world,” comments Mikko Vuolanto, product manager, Neldisc butterfly valves. “It is amazing how flexible the basic design has been in adapting to customer needs over the decades. For example, the Neldisc family conforms to even the newest, global fugitive emission standards, such as ISO 15848, and is fire-safe certified to the latest API 607 6th ed. while offering top-of-the-industry efficiency and performance especially in process industries.”
There have been numerous significant Neldisc deliveries over the years. One of the most memorable was in 2004 when Metso delivered the biggest Neldisc unit manufactured to date to a gas plant in the Middle East. In 2013 a heavy 80” double flanged L6 valve was delivered, together with over 280 other butterfly valves, to the Sadara project in Saudi Arabia. The heavy 80” valve is used as a shut-off for the cracked gas in a polyethylene plant.
Development based on customer needs
Many success cases have actually been manufactured, based on customer need and feedback. Thanks to the flexible basic design concept, the functionality of the valve has easily been extended to new applications. This approach, for example, has given birth to the erosion-resistant butterfly valve design, built specifically for a customer process requiring strong butterfly valve properties (maintenance-free) combined with extreme erosion resistance with metal seating – providing performance where a standard butterfly valve cannot reach.
Today, in addition to Neles Neldisc and Neles B-platform engineered butterfly valves, Jamesbury soft-seated Wafer-Sphere butterfly valves together create a complete offering all the way to pressure class ASME #2500, including the corresponding EN and JIS pressure ratings – a unique product portfolio in the business.
Solutions for the next 40 years
The development of Neldisc butterfly valves is still in full swing. The next-generation is already in the works, aiming to set the industry benchmark in the field of high performance butterfly valves during 2016. Metso is continuously adding to the great story of Antti Nelimarkka’s famous Neldisc butterfly valve family and, perhaps most importantly, ensuring its success for at least the next 40 years.
For more information contact Metso South Africa, +27 (0)31 502 9350, [email protected], www.metso.com
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