In this guide we’ll walk you through everything there is to know about actuators.
From the basics of how it works to step-by-step repairs and troubleshooting, you’ll gain a solid foundation of knowledge on how to operate and maintain Kimray’s actuators.
Use the table of contents to skip to different sections of the learning path.
A valve actuator is the device that “actuates”—or moves—a valve open or closed. It attaches to and works in conjunction with two parts: the valve body and the valve pilot. Two common types of valve actuators in upstream oil and gas operation are pneumatic and electric.
A Pneumatic Actuator like the one on Kimray's standard High Pressure Control Valve is typically comprised of an adjusting screw, breather plug, bonnet, spring, diaphragm assembly, and stem.
This assembly, sometimes referred to as a valve "Top Works", refers to the top section of the control valve and is bolted directly on top of the valve body. The exterior of this area consists of bolts and a hoist hook. Inside this area is a key to the valve’s movement: the actuator.
The "Bottom Works" refers to the valve body and trim together. This is where the process liquids or gases flow when the valve is open. The middle section contains the valve trim. Valve trim consists of a stem, packing, and coupling block, which gives operators a visual indication of valve travel.
A Pneumatic Actuator is one component of a Control Valve Package. There are two other parts that are critical to the actuator’s function: the Pilot and the Control Valve.
A Pilot senses pressure upstream or downstream of the valve and then does one of two things in response: sends a pneumatic signal that tells the actuator to open the valve or withdraws that signal to allow the valve to close (in a pressure-open/fail-close set up).
The diaphragm pressurizes when the actuator receives a pneumatic signal from a pressure pilot. In a back pressure application, the pilot senses upstream pressure and sends an output signal (gas) through tubing into the actuator of the valve.
As a result, the actuator actuates, driving the valve open or closed, depending on its configuration.
A control valve sits in the production line underneath an actuator. When the actuator receives a pneumatic signal from the pilot, the pressure pushes up on the actuator diaphragm. This opens the valve and allows process fluid or gas through the valve orifice (in a pressure-open/fail-close set up).
Pneumatic valve actuators require a source of pneumatic pressure in order to operate. The pressure can come from the natural gas available on most upstream oil and gas sites, or from air compressors.
Using compressed air is an increasingly popular practice as producers look for ways to meet their ESG commitments. A valve that uses compressed air is sometimes referred to as an air-actuated control valve.
Whereas the signal for a Pneumatic Actuator comes from a pressure pilot, the signal for an Electric Actuator comes from another outside source, like an Electric Pilot, Programmable Logic Controller (PLC), or Remote Terminal Unit (RTU). We refer to this configuration as an Electric Valve Controller Package.
In the case of an electric actuator on a High Pressure Control Valve in a back pressure application, the Electric Pilot receives an analog 4-20mA signal from a sensor, which represents a process condition.
The Electric Pilot conditions this signal and sends a corresponding signal (4-20mA) to the Electric Actuator of the valve.
As a result, the actuator actuates, driving the valve open or closed, depending on its configuration.
There are three primary factors to consider when selecting an actuator: Emissions, Automation Capabilities, and Cost.
As environmental regulations tighten, electric actuators are becoming more popular because they do not require the use of supply gas and therefore do not release emissions. If you want to reduce emissions with pneumatic actuators, you can power your pneumatics with compressed air or install a vapor recovery unit.
Another factor to consider is automation capabilities. A significant benefit to using electric actuation is the ability to automate valve functions. Simply put, automation gives you the ability to monitor and control your valves offsite. With a pneumatic actuator, you can do this by using an I/P valve controller, which converts an electric signal to pneumatic.
Cost is the third factor to consider. The upfront cost of a pneumatic actuator will typically be less than an electric actuator. However, when considering emissions management and the efficiency gains automation provides, electric actuators provide significant value.
One other benefit of electric actuation which is sometimes overlooked is worker safety.
Workplace injuries can be stressful and costly. Because electric actuation allows you to monitor and control production remotely, workers make fewer trips to the field. This means there are fewer opportunities for injuries to occur.
To speak with an expert about setting up your actuator or other control equipment, reach out to your local Kimray store or authorized distributor.
Kimray's Electric Actuator is helping energy producers increase efficiency, lower their emissions, and improve their operator safety.
In this video, Kyle and Alex take a quick look at a few of the key benefits it delivers for energy producers.
Below are four benefits our early adopter engineers and operators have been excited about:
The actuator features an on-board OLED screen, which allows operators to set it up and calibrate it with simple push buttons. It can be paired with most Kimray valve bodies, such the Stem Guided High Pressure Control Valve and Low Pressure Control Valve.
With actuation speed of up to 1/2" per second, the actuator provides accurate control of both liquid and gas applications. With a maximum thrust of 3200 lbf, it is the best option for larger valves and production volumes.
Rather than pneumatic supply, it uses electric power via line voltage or an onsite solar panel. This solution addresses a challenge producers face today with increased emission regulations where non-vent solutions are required.
With Modbus RTU over RS485, communication happens within seconds of a process change. This allows producers to monitor and control field processes remotely.
The Electric Actuator can be used anywhere your control valves are, including liquid dump, gas regulation, and artificial lift applications.
To learn more about Kimray's Electric Actuator or other zero emission solutions, contact your local Kimray representative or authorized distributor.
Actuators Learning Path
Installation, Repairs & Conversions
