The success of process valve automation depends on more than just individual parts; it takes a partner who understands complete systems, industry requirements and long-term operating performance to achieve high-quality designs. From engineering and commissioning support to lifecycle services, you will have everything you need to reduce complexity, improve reliability and protect performance over time.
This depends mainly on the torque curve, the installation space and the application. Scotch yoke actuators are especially suitable for applications requiring very high torques at specific positions of the swivel range, such as when opening or closing fittings. Rack-and-pinion drives, on the other hand, have an impressively compact design, a smoother torque curve and offer cost-efficient standard versions. The ultimate selection criteria are therefore determined by the required valve characteristics, the need for maintenance, space constraints and costs.
To create a reliable design it is not only the valve's nominal torque that should be taken into account, but also safety factors, starting and breakaway torques, holding torques, and possible emergency shutdowns. The medium itself together with the temperature and ambient conditions also affect the actual load. The aim is to design the drive so that it performs its function safely and reproducibly, even under real operating conditions.
In potentially explosive areas, drives must comply with the respective zones, ignition protection types, and temperature classes. This has a direct effect on the choice of materials, seals and suitable accessories. It is essential that both the individual drive and the complete solution meet all the relevant functional, environmental and safety requirements.
The pilot valve controls the pneumatic operation of the actuator and thus carries out crucial functions such as switching, exhausting, and it can be used to implement fail-safe concepts. It also influences the reaction behaviour and the time needed to actuate the entire unit. It is thus an important link between the control system and the pneumatic drive.
Selecting the flow rate depends on the time and force required for reliable actuation. In addition to the drive, the tubing lengths, any pressure losses, and the interaction with the other pneumatic components also play an important role. A suitable design helps to adjust switching behaviour, and it improves process reliability and energy consumption.
In these applications, pilot valves must meet the requirements of the environment and the safety function. Relevant criteria include ignition protection type, temperature class, materials and corresponding certifications. Depending on the application, robust, corrosion-resistant or safety-related variants are also useful.
A positioner ensures that the valve position precisely follows the target position specification. To do this, it compares the target and actual value, compensates for friction or process deviations and ensures stable, accurate control. Modern devices also offer diagnostic functions that facilitate commissioning and operation.
The required interface depends on the automation architecture. Typical options are those with analogue signals, HART protocols or other bus systems for integration into higher-level controllers. The aspects of positioners that are particularly interesting for any application are: they support digital integration, improve system transparency, and facilitate data exchange, diagnostics, and parameterisation.
In addition to providing precise control, positioners help to detect the condition of the drive/machine/system more quickly, simplify commissioning and make plant operation more transparent. Functions such as self-monitoring, plain-text displays, or diagnostic data support maintenance and troubleshooting. This reduces downtime risks and improves process stability over the entire life cycle.
A limit switch box provides reliable electrical feedback on the end positions of an automated process valve. Depending on the version, it also has an easily visible position indicator which facilitates inspection, commissioning, and maintenance on site. It is the go-to solution for clear position feedback.
This depends on the operating environment and requirements. Different sensors have different features; for example, the service life, vibration resistance and suitability for hazardous areas will vary between reed switches, inductive sensors, and mechanical microswitches. The selection should therefore always be tailored to the specific application, the required robustness and the required signal type.
The most important factor to bear in mind is how the feedback will be integrated into the existing control landscape. Depending on the application, potential-free contacts, PNP/NPN signals, NAMUR sensors or other electrical interfaces can be considered. Standardised interfaces and installation options help reduce integration effort and enable easier connection between different valve manufacturers.
To ensure they can be smoothly integrated, the mechanical and pneumatic interfaces should be specified according to the appropriate standard from the outset. Important standards include, for example, ISO 5211 for valves, as well as NAMUR and VDI/VDE interfaces for pilot valves, positioners, and sensors. This reduces compatibility risks and facilitates integration into multi-vendor projects.
Once several components are combined to form a process valve unit, the relevant requirements must be considered. Depending on the application, this includes proof of explosion protection, functional safety and the technical documentation for the overall solution. It is therefore not only the suitability of individual products that is important, but also how coherently all the components fit together and how well documented they are.
A configurator simplifies the selection process by using a structured method to determine the most important parameters and then suggesting suitable solutions. This allows configurations to be created more quickly, order codes to be generated, and CAD data, documentation, prices, and delivery times to be retrieved. This reduces engineering effort, reduces integration and compatibility risks, and accelerates project execution.