May 11, 2026
Mating Your Valve to Its Operation Mechanism: Differences in Mounting Options
Contributed by Zach Lehmann, Valve and Actuation Specialist
Valves are crucial components of almost every piping system. They control the flow, pressure, and distribution of the system media, though most valves require an actuator to properly operate and achieve these important roles. An actuator is a component that moves or controls a mechanism, in this case, a valve. There are many types of actuators with varying degrees of complexity, from simple levers and handwheels to fully automated control systems with electric or pneumatic control devices. In the ever-advancing world of valve design, valve versatility has become an increasingly common feature to highlight. Allowing users to accommodate multiple actuation options for a single valve makes spare valves more efficient, and using standardized mating dimensions and features allows third-party actuator suppliers to offer a wider range of adaptable products with ease.
The main point of connection between an actuator and a valve is the valve stem that protrudes from the top of the body. Actuators must both mate with the stem and have some method of anchoring the body of the actuator in place during the actuation stroke. Stems come in an array of shapes and styles, the most common of which include square, double-D, bore-and-key, starred, or splined. The most common way to anchor an actuator is by bolting it through the standard set of holes between the valve mounting plate and the actuator. The shape, size, and location of both the through holes and valve stems have been standardized to ensure all products are consistent and interchangeable. The most widely accepted standards come from the International Organization for Standardization (ISO), which fully defines all dimensions associated with connecting actuators to valves based on specific stem styles.
Simple manual lever actuators don’t need to be anchored to the valve body, and are often just connected to the stem via a bolt threaded into the top of the stem, allowing the operator to freely move the stem with manual force. Levers are often made solely by the valve manufacturer, with few third-party options, since there isn’t much mechanical advantage needed to operate the valve. As valves get larger and operational torque requirements increase, it becomes necessary to incorporate a gearbox with specific gear ratios to transfer the input force to the required torsional operating force. Gearboxes can be used on manual handwheels or in electric and pneumatic automated actuators and must be anchored to the valve body to function properly.
There are three main ways to mount these actuators to valves: via direct mounting, an adapter mounting kit, or remote mounting. Each mounting method has its own set of advantages and drawbacks.
Direct Mounting
Directly mounting an actuator to a valve uses the fewest components, making it the least expensive option. An additional benefit is that it provides the smallest physical profile of the assembled package, allowing it to fit into smaller areas. A drawback of a direct mount is that the actuator must perfectly fit the valve’s stem and bolt pattern (which can sometimes vary), limiting the number of actuator options and potentially increasing costs. Another drawback of a directly mounted actuator is the inability to verify the true valve position. With the valve stem completely hidden, there is no way to verify whether the actuator was turning the valve correctly. Even if someone were standing next to the valve, they wouldn’t be able to determine the valve stem’s position, which could cause issues with operating or troubleshooting the piping system.
Adapter Mounting Kit
Adapter mounting kits use a bracket that connects to the valve body on one side and the actuator on the other. A stem extender coupling is then used to bridge the gap made by the bracket for the valve stem and the actuator drive-bushing. These brackets are often windowed, allowing the stem to be visible during operation, which can help more easily identify any issues with the valve, including possible leaks from the stem. The incorporation of a bracket and coupling also allows the mating of dissimilar mounting patterns, enabling actuators to be used on a wider range of product lines. The drawbacks of a mounting kit include increased cost and longer assembly time due to additional components included in the total package. Additionally, the larger size profile could interfere with other components of the piping system.
Remote Mounting
The last main mounting style is remote mounting. This mounting style involves a support plate anchored to a wall or support structure in the vicinity, vertical to the valve, with a stem extender coupling used to connect the actuator to the valve. Remote mounting is often used to make an actuator more easily accessible from a pit or hard-to-reach area, or to keep an actuator that isn’t rated for submersion out of a flood zone. The drawback of this method is that each assembly is typically a custom build that requires environmental measurements and installation accommodations, which increase price and lead times. This mounting style also introduces stem alignment complications during installation that aren’t present in the other fixed valve body mounting options.
Selecting the appropriate actuator mounting style is a key consideration that goes beyond simple installation, as it also affects a piping system’s reliability, ease of maintenance, and costs. Whether direct mounting an actuator for its compactness and cost efficiency, or adapter kit mounting an actuator for its versatility and visibility, or remote mounting an actuator for its accessibility in challenging environments, each approach offers distinct benefits and trade-offs. By understanding these differences and evaluating the specific requirements of the piping system’s application, such as space constraints, operational demands, environmental conditions, and budgets, engineers and operators can make informed decisions that optimize both performance and long-term value. Ultimately, the right mounting solution ensures that the actuator and valve mate up correctly, safely, and efficiently.