Subsea Wellhead Ball–Valves Shutoff off Subsea Wellheads With Integrators for Medium Pressure Ball–Valves

Author / Editor: BILL MENZ / Dominik Stephan

Besides other applications, the challenges concerning medium pressure ball valves apply to oil & gas and hydraulic power units. Mostly, in all these applications, leakage is a serious issue, as the substances under pressure are often flammable. One of the principal challenges in designing a ball valve is determining how to generate sufficient force to create this contact pressure.

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(Picture: Swagelok)

Integrators charged with building chemical injection skids for mediumpressure applications face some formidable obstacles. Two of the chief obstacles concern critical fluid system components: mediumpressure instrument ball valves and reliable end connections for use with SAF 2507 (SAF 2507 is a TM of Sandvik seamless, duplex) tubing.

Under certain circumstances, instrument ball valves in the medium-pressure range are known to leak across the seat. After sealing at high pressure, they may have difficulty resealing at low pressure, especially if pressure in the system is being built up slowly. End connections for the valves pose a special challenge when the tubing required is made of SAF 2507, a corrosion-resistant material preferred in many aggressive chloride-containing environments.

When A Tight Sealing Counts...

Until recently, the market has not provided simple, easy-to-use, mechanical grip-type tube fittings for SAF 2507 tubing at pressures up to 15,000 psig (1034 bar). For such applications, the industry has relied on cone and thread fittings, which can be temperamental and difficult to fit and assemble.

AGI Beta Tests a New Ball–Valve

An integrator that has built skids for most of the major oil companies, AGI Packaged Pump Systems was acutely aware of the challenges concerning medium-pressure instrument ball valves and end connections for SAF 2507 tubing.

Therefore, when it accepted a contract to build two medium-pressure skids with SAF 2507 tubing . a chemical injection skid and a methanol injection skid – GI looked for a company that could provide new solutions...