- Published on Monday, 30 April 2012 10:31
- Written by Pieter Kok
Triple offset valves provide an efficient solution for critical and non-critical applications when positive isolation is required in upstream oil and gas operations. Their compact nature offers savings in weight and space and most importantly, cost.
Most onshore and offshore installations traditionally use ball valves and occasionally gate valves for the majority of flow isolation applications. Specifications typically call for 6D valves, but engineers seldom look beyond these specifications to other valve types with similar or better performance.
Many of these engineers are not yet aware that in many offshore isolation applications, a triple offset valve (TOV) offers benefits in terms of weight, overall dimensions and performance versus the standard ball or gate valve. A TOV can be the right choice for applications in the turret of a floating production storage and offloading vessel (FPSO), and in virtually all topside process applications of FPSOs and platforms such as separators, water treatment, gas compression and other systems.
Today’s TOVs, with pressure ratings up to ASME Class 1500 and zero leakage, cover enough applications to achieve significant savings in weight and space, as well as total cost of ownership.
The TOV design was introduced in the early 1970s as the next great development after the high-performance butterfly valve. The design is totally different from conventional or high-performance butterfly valves, however, offering a 90-degree non-rubbing rotation and metal-seated zero leakage.
Since the TOV was introduced, it has become a success with end users in the downstream oil and gas, process and power industries. It is recognized as a reliable, robust and valid alternative to gate and globe valves as well as ball valves.
The TOV concept is applied in a wide variety of applications from cryogenic to high temperature and from low- to high-pressure where positive isolation is required. Since its introduction, more than 500,000 TOVs have been installed worldwide with an extremely wide range of sizes and ratings and different materials—from WCB to duplex and from CF8M to titanium.