Seamless, Low-Cost Solution for Control Valve Replacement

On the decision to follow globe valve face-to-face dimensions according to ISA and B16.10

Whenever you introduce a new product or technology to the marketplace, there are barriers to entry. The number, variety, and complexity of these barriers vary from case to case, but barriers always exist in some form. Switching costs are one of the most common barriers to market adoption, and can take the form of direct monetary cost, or indirect costs, such as lost efficiency, retooling costs, training costs for operators, and so on.

The Clarke Valve™ strategy for the adoption of the Shutter Valve™ within the oil and gas industry was to target a switching cost of $0 for replacing legacy control valves.

The globe valve has been the most dominant control valve option for several decades running, with a worldwide installed base of over a billion valves. The globe also represents the valve type against which the Clarke Shutter Valve has the greatest competitive advantage. Therefore, these factors combine to make globe valves the ideal displacement target for Shutter Valve market penetration in oil and gas.

Challenge
In the case of industrial control valves, engineers at each facility have to consider many variables when originally sizing, purchasing, and installing the valves that help to manage their production processes. The cost for a globe valve can range from several hundred dollars to tens of thousands of dollars for an individual unit, depending on the size, trim, automation, and other factors. Hundreds, or even thousands of valves may be required for a typical installation, making cost a major driver. Furthermore, each of these valves has been fitted into a specific space in the piping of the facility; the distance between the two pipe connections being the “face-to-face dimensions.”

Different valve types have different face-to-face dimensions within the ISA and ASME B16.10 standards. This presented Clarke Valve with the opportunity to either match the existing face-to-face dimension for another valve type, or to request that ISA and ASME develop a unique face-to-face dimension for the Shutter Valve.

Since our stated goal is to minimize customer switching costs, Clarke Valve elected to match the face-to-face dimensions for globe valves which represent our ideal replacement target. The Shutter Valve™ provides an equivalent flow rate (CV) and other performance characteristics to globe valves with a much larger valve body.

So, the challenge for Clarke Valve™ was to design the Shutter Valve to match the face-to-face dimensions of commonly used globe valves, and thereby minimize the switching cost for oil and gas facilities.

Shutter Valve and globe valve side by side
Figure 1: Two ANSI Pressure Class 150 valves, side by side. On the left is the 4″ Shutter Valve, and on the right is a 4″ globe valve. Despite the significant size difference between each valve body and the attached actuators, the Shutter Valve delivers equivalent flow rate (Cv) to the globe valve and has been engineered to match the same face-to-face dimensions.

Solution
The ISA and ASME B16.10 dimensions differ slightly from each other, for each size and pressure class. Another variable to consider is that within the ISA standards, there exist both a Short and Long standard for each size and pressure class.

Through discussions with our shareholders and global oil and gas companies—and Saudi Aramco, in particular—we learned that the vast majority of valves specified into refineries and other sites typically follow the ISA Long standard. The engineering, procurement, and construction (EPC) firms that design refineries have generally settled on this preference.

So, Clarke has dedicated its casting, tooling, manufacturing, and quality control dimensions for ISA Long as our standard face-to-face dimension for production and inventory management, with ISA Short and ASME B16.10 face-to-face dimensions available upon request by the customer. Our ISA Short and ASME B16.10 variants use the same tooling as ISA Long, and only a require a small additional amount of machining to keep lead time impact to a minimum.

Shutter Valve and globe valve comparison
Figure 2: A 12-inch CV1345 Shutter Valve (left) has an equal face-to-face dimension “a” to the 12-inch globe valve (right), yet requires significantly less operating torque and can use a much smaller actuator, as a result.

Although the vast disparity in size between the body of Shutter Valve and a globe valve—the Shutter Valve can be 50% to 80% smaller—was identified as part of the challenge above, it actually represents another opportunity for positive differentiation. Clarke Valve elected to design unique integral flanged connections between the valve body and each pipe face that leverage the methods of rocket nozzle design to maximize performance, and achieve highly desirable fluid effects.

By designing a straight tapered upstream nozzle and a bell-shaped downstream nozzle (see Figure 3, below), we are able to virtually eliminate flow-accelerated corrosion, which dramatically increases the life of the valve body and adjacent piping. This means that each Shutter Valve can be rebuilt several times, before the valve body requires replacement, dramatically lowering the total cost of ownership for the customer.

Integral flange connections of the Shutter Valve
Figure 3: The Shutter Valve matches the face-to-face dimensions of globe valves, but the compact valve body has allowed Clarke Valve to develop asymmetrical upstream and downstream integral flange connections (left). Seen in cross-section (center), the upstream reducer is tapered in a conical design, while the downstream connection is more convex. The resulting flow pattern (right) at 100% open shows that the highest velocity process fluid is traveling down the center of the pipe (red), reducing the potential for erosion of the downstream pipe wall.

Our intention is to continue to use established standards like ISA Long and Short, and ASME B16.10, even after the Shutter Valve gains wider acceptance and achieves a substantial installed base. The massive installed base of globe valves for replacement is one reason for this approach. However, another part of our rationale is to maintain a low switching cost for the customer, who will always benefit from a high degree of interchangeability.

ISA and ASME will be engaged to include the Clarke Shutter Valve in their standards for the globe valve face-to-face dimensions, to educate the market on the interchangeability of the Clarke Shutter Valve for globe valves, worldwide.

Results
By choosing to follow the established guidelines for globe valve face-to-face dimensions, Clarke Valve has made it easy for oil and gas producers and process manufacturers to upgrade to the Clarke Shutter Valve with little or no switching costs. A secondary benefit is that the size differential between a Shutter Valve and most globe valves (of equivalent CV) has allowed Clarke Valve to design integral flanged connectors that deliver enhanced fluid dynamics to minimize flow-accelerated erosion and prolong valve life, achieving a significantly lower cost of ownership than a globe valve can provide.