Ball valves are relevant and applicable for usage in different fields, from the household to oil and gas. That is why they require occasional checks and maintenance. Experiences show that many specialists do not pay enough attention to the differences between inspection activities, so there are only failures and downtime. Everything you need to know about inspecting ball valves is covered in this guide.

Understanding the Basics: What is a Ball Valve?

A ball valve is a type of valve rotated a quarter of a turn with an inside solid spherical ball carrying apertures used to control the pressure or flow of a liquid or gaseous substance through the pipe. They incorporated some aspects that make it strong, flexible, and secure. This is why its components must be understood before performing any inspections.

Main Components:

• Body: The outer covering covers all the valve’s component parts.
• Ball: The spherical ball which rotates and controls the fluid.
• Seats: The leakproof structures that provide a basic level of sealing.
• Stem: Joints the ball with the actuator or lever.
• Handle/Actuator: It turns the valve on or off.

Why is regular inspection necessary?

• Prevent Leaks: Leakages can be prevented at the earliest stage of wear and tear.
• Enhance Lifespan: Maintenance is one way through which the valve can be made to last longer.
• Ensure Safety: Defective valves create dangerous situations.
• Optimize Performance: Regular inspections do not interrupt performance and flow.

Tools and Safety Measures

Pre-inspection preparation is important. Make sure that you have all the tools. And you are executing/ following safety measures.

 Tools you will require

• Adjustable spanner
• Tongue and groove plier
• Flathead screwdriver and Phillips Screwdriver
• Mirror or endoscope
• Ultrafine cloths and surface cleaners
• Leak detection fluid or detergent solution
• A lubricant which is suited to valves

Safety Precautions:

• Depressurize the System: Before starting the operation, turn off the fluid supply and remove the pressure
• Wear Protective Gear: Protect your hands, eyes, and, in some cases, your breathing when handling dangerous materials.
• Isolate the Valve: Make sure no fluid can accidentally get into the system while you are working.

Specialized Inspection tools

These tools are used when in hard-to-reach areas or without disassembling the valve:

• Endoscope Cameras: Show graphics of internal parts.
• Thermal Imaging Cameras: Identify when leaks occur and fluctuating temperatures.

 Inspection Methods

1. Visual Inspection

This is the simplest and most frequent method of identification of gross problems.

What to Check:

• External Body: Observe any cracks, rust points, dents, or corrosion.
• Handle or Actuator: The handle should not be bent, wobbly, or stiff when turning to avoid twisting the wrist.
• Connections: Observe leakages at flanges, threads, or welds or any form of misalignment found in equipment.
• Seals and Gaskets: Observe weariness, brittleness, or inaccuracy at a sealing location.

Tools:

• Flashlight or lamp (for when operating a normal light source proves ineffective) inspection.
• Inspecting mirror
• Magnifying glass

2. Leak Testing

 Unfortunately, leakage is typical for ball valves. Following are a few leakage tests.

Soap Test:

• Rinse valve joints and seams with soap water solution.
• Be careful to look out for bubbles that imply leakage.

Hydrostatic Pressure Test:

• First, inject the valve with water and apply pressure heads utilizing a hydrostatic pump.
• Then, look for signs of low pressure or leakage from the outside.

Air Bubble Test:

• First, dip the valve in water.
• Then, open the valve, let in pressurized air, and look out for the number of bubbles released.

3. Functional Testing

Functional testing evaluates the valve functionality.

Handle movement:

• Use the handle to open and close positions.
• Then, check whether it works smoothly without any resistance or rigidity.

Partial movement:

• Observe whether the valve can maintain its intermediate position beyond a fully open or closed one.

Actuator test (for automated valves):

• Test the actuator either by a manual process or by the automation system
• Confirm that the actuator rotates continuously to operate the valve.

4.  Pressure Testing

Pressure tests show that the valve can bear specific pressures during its operation.

Seal leakage test:

• Shut the valve and put force on one of the sides.
• Then, observe leaks on the other side.

Shell test:

• Pressurize it to check the structural dimensions of the valve body.

Vacuum test:

• Put a vacuum to the valve and check for pressure raises that would mean leakage.

5. Internal Inspection

Disassemble the valve and check for damage or wear on the inner parts.
If the outside inspection indicates possible problems or during regular, separate the valve to look at internal parts. Do the following steps:

Remove the valve:

• Please turn it off completely.
• Unscrew the valve from the pipeline and use the wrench to do that or any tool that is considered appropriate at that point.

Check the ball:

• Check for any signs of scratches, pits, or deformation on the face of the ball. The flow might be adversely affected by minute defects or leaking.
• Move the ball to check the smooth movement. Resisting or hardening may imply wear or even dirt accumulation.

Check the seats:

• Seats are made from materials such as PTFE. Look for any signs of crack, chip, and flattening.
• Seats should be sealed tight on the ball.

Analyze the Stem and Seal:

• Look for corrosion or wear out on the stem
• Inspect the O-rings or packing for signs of deterioration. Replace them if they appear marked or look flaky.

Clean All parts:

• Apply a surface cleaning solution to help remove loose contaminants, scales, or chemicals.
• To avoid corrosion, clean and dry all parts before reassembly

Common signs of damage:

• Heavy grooves on the ball with traces of rust
• Worn seat faces that lose seal tightness.
• Severely rusted or bent stem.

Cleaning and Reassembling:

 If you want the ball valve to remain longer and work smoothly, then follow these steps

• Clear Debris: Clean all the parts of the valve well and remove any dirt or mess if there’s any.
• Lubrication of Moving Components: Dropping a few drops of oil in the moving areas of the machines will prevent wear.
• Reassembled Correctly: Fit everything again according to the manufacturer’s specifications.

6.  Advanced Non-Destructive Testing

Advanced methods can detect hidden defects while assisting with critical applications.

• MPI-Magnetic Particle Inspection: Identifies both external and internal defects in metal-based parts.
• UT-Ultrasonic Testing: Exploratory tool that generates sounds to detect defects or strains within a structure.
• DPT-Dye Penetrant Testing: Discloses surface cracks by using penetrant dye and developer.

7. Flow Testing

Flow testing is used to see whether it flows properly or restricts the flow when closed.

Steps:

• Put the flow meter upstream of the valve.
• Find out what your flow meter is showing and compare it to your expected flow rate.
• If it is different, then maybe there are varying restrictions or partial obstructions within the valve that can be resolved.

8. Endurance Testing

Endurance tests increase the long-term usage for testing durability.

Process:

• Open and close the valve several times.
• Special attention should be paid to any deterioration in its performance, such as operating torque, leakage case, etc.

9. High temperature and Cryogenic test

Special tests like high temperature and cryogenic tests are carried out to determine the ball valve’s performance under specified temperature conditions.

High temperature:

• In this test, the valve should be exposed to 400°C and an internal pressure of 1.5 times the rated pressure, while the medium can either be air or water when carried out on a test.
• This process helps to check the valve sealing deformation and leaks.

Cryogenic test:

The cryogenic test is conducted based on BS 6364 standards.

• Place ball valve liquid nitrogen at an extremely low temperature of -196 degrees centigrade and apply helium pressure inside the valve
• This process tests the valve sealings and checks their function at very low temperatures.

10. Torque test

Torque testing measures the force needed to use the valve.

• Open and close the valve with the help of a torque wrench.
• The measured torque must be compared with the given torque by the manufacturer.
• High torque means that there is wear and internal resistance.

Inspection of ball valve for a specific environment

As you know, ball valves can function in various environments, and flow control needs particular examinations.

In the industrial environment:

• Inspect the equipment for chemical erosion, heat injury, and signs of debris accumulation.
• Check the automatically operated actuators and confirm that electrical or air pressure systems work properly.

In high-pressure system:

• Seek signs of pressure-induced stress cracking or deformation.
• Verify that the valve’s working pressure rating can meet the pressure rating of the system

In residential plumbing:

• Check for scaling and mineral deposits found in water systems.
• Plumbing materials must be compatible to prevent galvanic corrosion.

Preventive Maintenance: Prolonging Valve Life

These include regular checkups, which assist in minimizing hefty expenses for repairing or replacing an item. Add these habits to your routine:

• Lubrication: The lubricant should be applied according to the manufacturer’s recommendation so as not to cause friction between the moving parts.
• Seal Replacement: Replace seals and O-rings in case they look rusty, old, and worn out.
• Routine Inspections: Make it a habit to monitor the valve for any signs of trouble that may cause large problems.
• Proper Storage: If you do not use the valve, let it dry to avoid rust or dirt on the valve surface. Store them in clean, dry places.

When to Replace a Ball Valve

 Many times, inspection indicates that something cannot be fixed anymore.

• The ball is permanently out of shape due to severe corrosion.
• Seats do not form a perfect seal, not even after replacing the seats.

There is leakage, and it becomes recurrent after some repair has been conducted.

• The handle or actuator itself is no longer operational sometimes or the whole time.

Conclusion

Methods used to inspect a ball valve depend on various parts of the ball valve and its surrounding environment. Maintenance activities involving visual inspection, leak tests, function tests, and other complicated tests such as NDT enable the confirmation of the correct function of the valve. This article explains how you should always know how to observe and solve problems with your ball valve at an early stage. Always consult with the valve manufacturer, Plumberstar, or a professional engineer for special valve inspections.