There are a variety of ways to test an actuator valve. Some manufacturers require that all valves be tested by using a specific test method.
Others, like Emerson, don’t require any tests at all.
However, if you’re in the business of manufacturing valves, you should be familiar with the test methods and know how to conduct them.
Read on to learn more.
What is an Actuator Valve?
An actuator valve is a mechanical device powered by an energy source to control the operation of a valve.
It interfaces with and collaborates with two essential components: the valve body and the valve pilot.
The actuator exerts influence on the valve stem, enabling the opening or closing of the valve.
Types of Actuator Valves
Various types of valve actuators cater to specific needs and applications. The primary classifications are as follows:
Manual Actuators: Operated by hand, these actuators don’t rely on an external power source.
Pneumatic Actuators: Utilizing compressed air for motion and positioning, pneumatic actuators are cost-effective and easy to operate, making them a common choice.
Hydraulic Actuators: Employing hydraulic pressure, these actuators offer increased power, making them suitable for larger valves compared to pneumatic actuators.
Electric Actuators: Driven by an electric motor, electric actuators provide precise and reliable control over valve position, albeit at a higher cost than pneumatic or hydraulic counterparts.
Electro-hydraulic Actuators: Combining the advantages of both electric and hydraulic actuators, these systems use an electric motor to regulate hydraulic fluid flow for precise valve positioning.
Valve actuators can be further categorized into rotary and linear types based on the motion required for the specific valve.
Rotary valve actuators, suitable for valves with rotational motion like ball, butterfly, and plug valves, contrast with linear valve actuators designed for valves with linear motion such as gate and globe valves.
How Do You Test an Actuator Valve?
Testing an actuator valve involves several crucial steps:
Step 1: Pressure and Leak Testing
The first step in testing an actuator valve is to ensure that it is operating properly.
Evaluate the valve’s performance under pressure, identifying and fixing any leaks in both the valve body and the actuator.
Many models come with an inbuilt position sensor, and you can use this to determine the length of the actuator’s extension.
Step 2: Functional Testing
Verify the actuator’s ability to open and close the valve correctly, either manually or through its control system.
Test the actuator’s position against a reference position sensor, which is almost always an LVDT.
During this test, the valve’s position will oscillate back and forth around the null position for some time
.
The electrical component of an actuator is called the motor contactor. It tells the actuator whether to open or close the valve.
This is fuse-protected and gives torque for the valve’s movement.
When the motor fails, the valve will not move, so you’ll need to test its duty cycle and insulation class to determine if it’s the valve or the motor.
If the valve fails to move even when in manual mode, the motor is the problem.
Step 3: Environmental Testing
Simulate various environmental conditions like temperature, humidity, and vibration to ensure the actuator and valve can withstand diverse scenarios.
For example, check the valve’s performance by running a fire test. This involves simulating a fire in a factory or plant.
The purpose of this test is to ensure that the valve is secure against fire.
A basic fire test involves exposing the valve to high-temperature flames for 30 minutes and then cooling it down with cold water to simulate a fire.
This process exposes the valve to extreme thermal shock.
Step 4: Dynamic Testing
Validate the entire variable valve timing circuit’s operation, including the actuator, through electrical, mechanical, and hydraulic assessments.
Step 5: Actuator Leak Test
Pressurize the actuator, such as a Fisher Spring & Diaphragm Actuator, to identify and rectify any leaks.
Step 6: Torque Load Testing
Examine the actuator’s ability to withstand specified torque loads, ensuring it performs reliably under required forces.
Check the performance of an actuator valve by measuring its margin.
If the margin is greater than zero, the valve is deemed capable of performing its intended function.
This margin can change due to changes in the valve’s operating requirements and actuator capacity.
To determine whether the margin is within acceptable limits, the end user needs to devise meaningful acceptance criteria.
However, this approach can’t be used on every actuator valve.
Step 7: Torque Switch Settings Testing
Check the torque switch settings to confirm they are accurately configured and operating as intended.
Step 8: Stall Capability Testing
Assess the actuator’s capacity to maintain its position under stall conditions, confirming its stability.
Step 9: Gear Efficiency Specifications Testing
Examine the actuator’s gear efficiency specifications to ensure compliance with required standards.
Step 10: Certifications
Conduct valve actuator testing according to various standards and certifications like CSA C22.2, EN 15714-1:2009, EN 15714-2:2009, and EN 15714-3:2009.
Common Issues that Can Be Detected During An Actuator Valve Testing
During actuator valve testing, various issues can be identified, providing valuable insights into the system’s performance and safety. These issues include the following:
Leaks
Detecting leaks in the valve or actuator is critical, as they can compromise performance and pose safety risks.
Insufficient Pressure
Inadequate pressure supplied to the actuator may hinder its ability to operate the valve effectively, impacting overall performance.
Valve Issues
Problems within the valve, such as sticking or malfunctioning components, can directly influence the actuator’s performance.
Slow-Moving or Drifting Actuators
Unexpectedly slow movements or drifting from the intended position may signal underlying issues with the actuator or its components.
Misalignment
Proper alignment between the actuator and valve is crucial for optimal functionality; misalignment can impede intended operations.
Worn Seals or Components
Wear or damage to seals and components may lead to leaks or suboptimal performance, impacting the system’s efficiency.
Faulty Limit Switches or Monitoring Devices
Malfunctioning limit switches or monitoring devices can adversely affect the actuator’s performance and responsiveness.
Stall Capability Issues
An inability to maintain position under stall conditions may point to design or component issues within the actuator.
Gear Efficiency Specifications Issues
If the actuator fails to meet specified gear efficiency standards, it can impact overall performance and reliability.
By systematically identifying and addressing these issues during testing, the correct and safe functionality of the actuator valve can be ensured. This proactive approach contributes to the system’s efficiency and reliability.
What are the Signs that An Actuator Valve Needs Testing
Recognizing signs that an actuator valve requires testing is crucial for maintaining optimal performance and ensuring equipment safety. These signs include the following:
Loud Noises
Unusual hissing or clanking sounds emanating from the valve may be indicative of an underlying issue with the actuator valve, necessitating testing.
Incomplete Opening or Closing
If the actuator valve fails to open or close entirely, it signals potential problems within the actuator or valve that warrant thorough testing.
Driveability Issues
In vehicles featuring variable valve timing, experiencing driveability issues or encountering fault codes related to valve timing may signify problems with the actuator valve, warranting prompt testing.
Changes in Performance
Any deviations in the actuator valve’s performance, such as slower operation or reduced torque, should prompt testing to identify and address potential issues.
Leaks
The presence of leaks in the valve or actuator indicates a problem that necessitates immediate testing to prevent further complications.
Contamination
If the valve is contaminated with dirt or debris, it signals a potential issue requiring testing to assess and rectify the problem.
Environmental Conditions
Exposure to extreme environmental conditions, such as temperature or humidity, can impact the actuator valve’s performance, making regular testing essential to ensure proper functionality.
Key Takeaway
To test an actuator valve, you should first determine its working capability.
An actuator must be able to sustain a certain pressure level without leaking, which is known as pressure and leak testing.
A valve is tested to determine its performance under pressure by causing a pressure decay over a set time.
This procedure can determine whether the valve can withstand a specified pressure level.
By consistently conducting tests on actuator valves, potential issues can be identified and addressed proactively, mitigating the risk of significant problems.
This approach contributes to the overall safety and reliability of the equipment.
Besides partnering with a reliable actuator valve manufacturer, regularly assessing your equipment will prolong its service life.
