Electric Actuators For Modulating Ball Valves

An electric actuator in a modulating ball valve system precisely adjusts the valve's position based on control signals, making them essential for applications requiring precise modulation. There are electric actuators for 2-way and 3-way modulating ball valves. This article explores the technical specifications, operational mechanisms, and integration capabilities of these actuators.

Modulating ball valve actuator types

• Belimo actuators for modulating ball valve: The Belimo actuator (Figure 1 right) can be hand-mounted onto the valve without tools, requiring only vertical movements to ensure proper alignment of the pins with the flange holes. The mounting orientation is adjustable in 180° increments relative to the valve. Additionally, the actuator's rotation angle can be finely tuned in 2.5° increments using a clip, allowing precise setting of the valve's maximum flow rate. It features overload protection, eliminating the need for limit switches by automatically stopping when the end stop is reached. The actuator can be easily removed by clicking it out and can be used to manually rotate the valve spindle. It includes an integrated interface for BACnet MSTP and Modbus RTU, enabling it to receive digital control signals from the control system and provide real-time status updates. BACnet MSTP facilitates HVAC and lighting control, Modbus RTU is known for its reliability in industrial automation, and MP-Bus simplifies HVAC component integration.
• J4C actuators: J4C actuators (Figure 1 left) feature robust construction with options for fail-safe (Battery Safety Return, allowing the actuator to fail open or closed during power loss) and modulating (Digital Positioning System) control with analog signals like 4-20 mA or 0-10V. These analog signals allow for fine-tuned adjustments of devices like variable speed drives, dampers, and valves, ensuring optimal environmental conditions and energy efficiency.

They provide high torque, fast operation, and are suitable for various aggressive and corrosive media. With an operating torque range of 20-300 Nm, these actuators are suitable for various valve sizes. For maintenance, separate spare parts are available for the ball valve and the actuator itself.

Read our modulating valve overview article for more information on the design and applications of modulating valves.

How to select a modulating ball valve with actuator

1. Configuration: 2-way modulating ball valve is suitable for simple on/off control and suitable for systems where precise flow adjustment is needed, such as HVAC systems. 3-way configuration is used in systems where the flow needs to be redirected between different paths. It is ideal for applications requiring the mixing of different media or distributing flow to multiple outlets.
2. Flow requirements: Determine the required flow rate and select a valve with an appropriate Kv value. If the flow rate is less than required, the system may not perform efficiently, leading to inadequate heating, cooling, or fluid transfer. Conversely, if the flow rate is too high, it can cause excessive pressure drops, increased wear and tear on the valve and system components, and potential damage or failure of the system.
3. Pressure and temperature: Ensure the valve can handle the maximum pressure and temperature of the application.
4. Voltage compatibility: Verify the actuator's voltage compatibility with the system. Incorrect voltage can lead to actuator failure, resulting in operational downtime, increased maintenance costs, and potential damage to other system components.
5. Control signal: The correct control signal allows for accurate modulation of the valve position, ensuring optimal performance and efficiency. It also facilitates communication with building management systems or other control systems, enabling centralized monitoring and control. Choosing an actuator that supports the desired control signal (e.g., 0-10 V, 4-20 mA, BACnet MSTP) is essential for achieving precise control and seamless integration with existing systems.
6. Protection rating: Select an actuator with an appropriate IP rating for the installation environment. IP54 is suitable for indoor use with protection against dust and splashing water. IP67 offers higher protection against dust and water immersion, suitable for harsher environments.
7. Material compatibility: Ensure the valve materials are compatible with the media being controlled. This prevents corrosion and extends the valve's lifespan. Typical housing materials are:
   1. Brass: Commonly used for its good resistance to corrosion and dezincification, making it suitable for water and steam applications.
   2. Stainless steel: Known for its superior resistance to aggressive and corrosive media, ideal for harsh environments and chemical applications.
   Typical seal materials are:
   1. EPDM (Ethylene Propylene Diene Monomer): Excellent resistance to water, steam, and a variety of chemicals, often used for sealing in HVAC and water treatment systems.
   2. PTFE (Polytetrafluoroethylene): High chemical resistance and durability, suitable for a wide range of industrial applications involving aggressive chemicals.
   3. FKM (Fluoroelastomer): Provides excellent resistance to oils, fuels, and high temperatures, making it suitable for demanding industrial environments.

Read our chemical compatibility chart for more information on the compatibility of various materials with different media.

8. Ball bore design: L-port is suitable for diverting flow between two different paths. It is commonly used in applications where the flow needs to be directed from a single inlet to one of two outlets. T-Port is ideal for mixing or distributing flow between three different paths. It allows for more complex flow configurations, such as combining flows from two inlets or distributing flow to two outlets simultaneously. Read our ball valve circuit function article for more information on ball valve circuit functions and bore designs.

Additional features

• Manual override: Consider actuators with manual override options for emergency operation or maintenance.
• Adjustable operating range: Some actuators offer adjustable operating ranges, allowing fine-tuning of the valve's maximum flow rate. This feature is particularly useful in applications requiring precise flow control.
• Maintenance and cleaning: Valves with a 3-piece design can be disassembled for thorough cleaning, ensuring long-term reliability and performance. This is important for applications where cleanliness is critical.