Tier 6: When additive manufacturing unlocks new possibilities in flow control

From simple on/off isolation valves to Tier 5 multi-stage DRAG® technology, we have looked at how new design innovations address critical issues such as higher pressure drops, greater velocity control, reduced noise, and improved reliability. But what happens when even the most advanced conventional trim designs reach their limits?

Across power generation, energy, petrochemical and a range of other industrial process applications, today’s engineers are being asked to manage increasingly severe operating conditions. Higher pressure differentials, aggressive fluids, erosion risks, flow instability and demanding retrofit requirements are pushing traditional manufacturing techniques to their practical boundaries.

In these situations, the question for you is not simply which valve to choose. Rather, the challenge has become one of whether conventional manufacturing methods can physically create the flow path needed to solve the problem.

This is where Tier 6 brings something entirely new to the world of flow control technology. By leveraging additive manufacturing, commonly known as 3D printing, engineers can create valve trims with complex internal geometries that would be impossible to produce using traditional machining or stacked-disk construction. The result is a new generation of severe-service valve solutions capable of delivering levels of control, reliability, and operational performance previously considered out of reach. For instance, 3D-printed trims may be necessary when aiming for extremely high turndown or a highly characterised or speciality-characterised stroke-to-capacity curve.

Many severe-service applications have one thing in common: they force fluids to undergo significant changes in pressure, velocity and energy. So as your plant’s process operational conditions become more extreme, controlling that energy safely becomes increasingly difficult.

Engineers may need to:

For decades, multi-stage trim technologies such as IMI's DRAG® valve trim have successfully addressed many of these challenges. The principle itself is straightforward. Rather than allowing fluid pressure to drop in a single destructive step, the pressure reduction process is divided into multiple smaller stages. Each stage carefully manages velocity and energy dissipation, reducing the risk of damage while maintaining stable control.

This approach has transformed severe-service valve performance and remains one of the most effective solutions available today. However, every technology has practical limits.

A Tier 5 DRAG® trim can incorporate more than 30 stages of pressure reduction, achieving exceptional control performance in many demanding applications. Yet the design is still constrained by traditional manufacturing methods, as stacked-disk designs require a minimum material thickness between flow paths.

Conventional stacked-disk trims are built from multiple precision-machined components assembled together to create flow paths. Each individual disk must contain sufficient material, known as land width, to maintain structural integrity during the manufacturing and operational phases. While highly effective, these requirements impose limits on how closely flow passages can be packed and how complex their geometries can be. In other words, there comes a point where the desired flow path exists in theory but cannot be manufactured in practice using conventional techniques.

For many years, this manufacturing limitation defined the upper boundary of severe-service trim design. Today, additive manufacturing changes that equation completely.

A Tier 6 valve uses additive manufacturing to produce trim components layer by layer and directly from a digital design model. Instead of machining individual components and assembling them into a stacked structure, the trim can be manufactured as a single monolithic component with intricate internal passageways. This allows engineers to focus entirely on creating the optimum flow path rather than designing around manufacturing constraints. The result is a significant step change in design freedom and in complete flow-control customisation.

Traditional stacked-disk designs require material to be present between flow paths. Additive manufacturing significantly reduces these restrictions, allowing more pressure-reduction stages to be incorporated within the same physical envelope. This enables greater control over velocity, turbulence and pressure recovery.

Conventional manufacturing generally creates flow paths in two dimensions. Additive manufacturing allows engineers to utilise all three dimensions of available space. The flow path is able to curve, expand, contract and redirect fluid in ways that were previously impossible, creating entirely new approaches to energy management.

By increasing geometric flexibility, engineers can precisely tailor flow characteristics to their specific operating conditions. This creates opportunities to optimise performance for your most complex applications where standard trim solutions may struggle.

New designs no longer require entirely new manufacturing routes. Because the same additive manufacturing process can be used across many configurations, engineers can develop and validate specialised solutions more quickly than with traditional production methods.

The true value of Tier 6 technology lies not in its innovation. The value is that it enables engineers to solve problems that were previously unsolvable. One example involved an application requiring an expanded flow path capable of handling particle-laden service while minimising the risk of clogging.

Using additive manufacturing, engineers created an innovative upside-down V-shaped flow path within the trim itself. The design utilised vertical space that would otherwise have been inaccessible with conventional stacked-disk construction. The resulting trim incorporated ten expanding stages that controlled velocity while maintaining a larger inlet flow area, which improved the passage of entrained particles. This solution was specifically engineered around the process challenge rather than around any trim manufacturing limitations.

Not every severe-service challenge requires a completely new valve. Many operators face performance limitations in plant assets that have significant operational value. In one retrofit application, traditional brazed assemblies were experiencing issues associated with wet-steam erosion, localised seat damage and thermal fatigue. These conditions reduced reliability and led to a deterioration of the internal flow passages over time.

Using additive manufacturing, engineers developed a replacement trim as a single monolithic component fabricated by direct metal laser sintering (DMLS). The redesigned trim increased the number of pressure-reduction stages while maintaining the original flow coefficient requirements. The result was improved drainage performance, lower velocity levels and enhanced long-term durability, all while fitting within the existing installation.

For operators seeking to improve performance without extensive plant modifications, this illustrates an important advantage of additive manufacturing: bespoke solutions can often be developed around your existing equipment constraints.

As with every technology featured in the #ChooseTheRightValve series, Tier 6 is not automatically the best solution for every application. In many services, a conventional control valve remains the most appropriate and cost-effective choice. In others, Tier 5 DRAG® technology provides the ideal balance between performance and complexity.

Tier 6 becomes relevant when application demands exceed the practical limits of traditional trim design, when unusual flow characteristics are required, or when a highly customised solution is needed to address a specific operational challenge. The goal is never to specify the most advanced technology for its own sake. Rather, the goal is to select the technology that delivers the required performance, reliability and lifecycle value for the application. And that principle remains at the heart of choosing the right valve.

Tier 6 represents the highest level of single-phase severe-service flow control within the IMI portfolio. It provides you with unprecedented flexibility in trim design and performance optimisation. Yet some applications introduce another challenge altogether: multi-phase flow.

When liquids, gases and entrained particles interact simultaneously, entirely different flow-control considerations emerge. Addressing these conditions often requires specialised trim concepts developed specifically for multi-phase service. In the next instalment of #ChooseTheRightValve, we'll explore how valve technologies evolve once the fluid itself becomes the next engineering challenge.

View the whole series here.