Advanced Machining Allows Subsea Valves To Handle the Pressure

BEL Valves Ltd. (Newcastle upon Tyne, UK) has be using DMG MORI SEIKI (Gloucestershire, UK) machines at its Newcastle factory for years. It now has two SL2500s, three NL2500s, three NL3000s, one SL603, two NVX5100s, three NZX2000s and one Taiyo Koki vertical grinder, along with DuraTurns at its Indian plant. And it is about to take delivery of a NZX4000.

The company is a wholly-owned subsidiary of British Engines, and it specializes in the manufacture of gate, ball, check, HIPPS, needle, double isolation and globe valves in subsea and surface oil and gas applications where pressures can be 20,000 psi. The key element of working in this industry is reliability and all the valves produced by BEL are bespoke. They are designed to suit the individual requirements of a particular project, which may vary considerably according to factors such as the temperatures and water depth, which can be as much as 3000 m.

Jonathan Lamb, the group production director of BEL Valves says, “The oil and gas industry works with preferred suppliers, and we have been testing our valves in subsea applications since 1992. To produce a reliable solution, we use finite element analysis techniques to help us to design for the very high pressures involved. Preventing fugitive emissions where corrosive and toxic gases leak from a valve is also a high priority. Achieving exceptional surface finishes on our components is a major factor in achieving this.”

Here is a demonstration of a DMG / Mori Seiki NL3000 turning center performing a semi-finish turn.

He continues, “Overall, the cost of the valve itself is small in relation to the project cost of an oil and gas installation. However, it is a vital part of the system as the time and effort required for its installation is high. If it fails, the disruption to oil and gas production can be immense. To give some idea of the scale of these projects, the valve can be paid for within the first few hours of production.”

The need for reliability is paramount at BEL Valves, which is why it chose to install these DMG / MORI SEIKI machines. Lamb adds, “We selected them based on their build quality.” The slideways on the NL machine tools are 30 percent wider than a conventional machine and the torsional rigidity is 100 percent better than the previous model and spindle rigidity is 50 percent greater.”

“We cut tough materials such as stainless and exotic alloys at low speeds. In particular we have very demanding, 12 mm deep grooving operations and, without a doubt, the damping capability of the NL produces a better result. The 6 mm trepanning blade can cause less rigid machines to resonate, causing the tip to shatter and wrecking the turret. Additionally, the high output motor on the NL has plenty of torque at low speed enabling us to use its power to the full.”

The penalty for late delivery on BEL Valves contracts can be substantial. Lamb notes that “the extra hourly rate can be as little as £1. This is insignificant when compared to the potential penalties we could face for late delivery should the machine break down, so it makes economic sense to buy the best available equipment.”

DMG / MORI SEIKI achieves an average response time of 0.8 days and spare parts are delivered from its Stuttgart facility next day 95 percent of the time. “The service we get from them is very good and much better than most machine tool companies,” adds Lamb. “Service support is excellent as we get someone onsite next day or the same day. The engineers are highly competent in reaching the correct fault diagnosis.”

“It could be our fault or their fault, but fixing any problem quickly is the most important thing,” he continues. “Niggling recurring problems, or a machine being broken down for a week would be completely unacceptable to us. I am glad to say that we have never had a lengthy break down on these machine tools.”

The business model at BEL Valves is to manage all the processes in-house from raw material to finished part in order to achieve exemplary customer service and achieve on time delivery. Although the company has a long term sales book, its sales vary wildly, generating spikes in demand.

It organizes its machining cells to suit the size of its products and has to respond rapidly to changing demand so new machine delivery lead times are important. It frequently purchases machines from DMG / MORI SEIKI European stock. Lamb concludes, “They give us the ideal combination of reliability, quality, rigidity, delivery and service.”

BEL Valves Ltd., St. Peters, Newcastle upon Tyne, NE6 1BS, UK, +44 (0) 191 265 9091, Fax: + 44 (0) 191 276 3244, sales@belvalves.com, www.belvalves.co.uk.