NTGD VALVE CO. LTD
  sales@ntgdvalve.com       Egnlish    Español    Français   Português    Русский

Valve Manufacturers

» Valve Manufacturers

Common Causes of Ball Valve Failure and How to Repair

November 2, 2021

Introduction

Ball valves are known for their durability and reliability, and are the valve of choice in a wide variety of on/off applications. While ball valves generally hold up well in intense environments, like any other system component, they carry the risk of damage or failure. Multiple factors affect a ball valve’s lifespan, including system media, media temperature, media pressure, cycle frequency, actuation type and proper ball valve maintenance. Read on for some of the most common causes of ball valve failure and their solutions.

 

Factors That Impact Ball Valve Lifespan

Many manufacturers will provide an estimated lifespan for their ball valves, but this range can be affected — either reduced or extended — by a variety of factors.

Actuation: Depending on your system’s intended cycle speed and available power sources, ball valves will be powered by pneumatic (air), electric (motorized) or hydraulic (fluid) actuation. Incompatible actuators and system conditions can lead to valve failure; however, in most cases, actuators will far outlive the ball valves they control.

Design: One- and two-piece ball valves do not allow for in-system maintenance or repair, which means they must be replaced when components fail. Three-piece ball valves, however, are designed so that the seats and seals can be removed and replaced without removing the entire valve from the system. Because of this, three-piece ball valves will far outlive one- and two-piece ball valves if properly maintained.

Media: Ball valves are generally intended for the on/off control of fluids and gasses without solid particulates, since any particles in the media can abrade the valve seals and shorten their lifespan. Lubricative media such as oils can in fact reduce seal wear and extend the life of the valve. 

Serviceability: Seals are often the first component to fail in a ball valve, since they are made of softer materials (normally P.T.F.E.) than the valve body and are subject to the most wear and tear. One-piece and two-piece ball valves must be replaced when their seals expire; however, the valve can normally be replaced without replacing the actuator, which is typically the highest cost portion of the assembly. On the other hand, three-piece ball valves allow for easy replacement of seals.

Source: It’s generally good practice to source ball valves made in the same country as your system equipment to ensure compatibility and maximum lifespan.

Temperature and pressure rating: Ball valves used in high-pressure or high-temperature applications will need to be serviced or replaced more frequently than those in lower-pressure applications.

Cycle Frequency: The lifespan of a ball valve is directly related to how often the valve is cycled (turned on or off). A valve in a high pressure application that cycles only once or twice a day may long outlast a valve in a low pressure application that cycles every minute.

Valve materials: Overall, metal ball valves have a longer lifespan than those made with PVC or other synthetic materials. Media is a major determinant of the materials for ball valve bodies and accessories, so ensuring material/media compatibility is essential.

 

Potential Risks Resulting From Ball Valve Failure

Ball valve failure means more than just the time and money it takes to replace the valve. Potential risks range from merely inconvenient to downright dangerous.

Media leakage: A failed valve can cause the media in the piping system to leak into the surrounding environment. Depending on the media, this can expose workers and equipment to toxic chemicals, poisonous gasses, extreme temperatures or dangerously high pressure.

Production downtime: A failed valve halts production, which results in lost revenue, wasted time and employees left with nothing to do while they wait for repairs.

Repair costs: Periodic equipment repairs are expected in any industrial setting, but repairs that result from preventable valve failures can end up costing you more than you budgeted for.

These potential risks illustrate the importance of regular inspections and preventative maintenance. In order to ensure the safety of workers, longevity of your equipment and optimized costs, make sure your facility performs regular inspections and maintenance procedures.

 

14 Common Ball Valve Failures & How to Repair

  1. Actuator incompatibility: Electric, hydraulic or pneumatic actuators that are too powerful for the valve they control risk damaging the valve itself. Conversely, some actuators may not have enough torque output to turn the valve

Solution: Choose an actuator that suits both the type of valve it controls and the system conditions. If you are unsure whether the issue lies in the actuator or the valve itself, remove the ball valve from the actuator and try to cycle the valve manually. If the valve turns freely you will know it is an issue with the actuator. If your actuator features a manual override handle you can attempt this without removing the valve from the actuator. If possible, try to source the valve and actuator from the same manufacturer to ensure compatibility.

  1. Cavitation: Cavitation occurs when the pressure of liquid media inside a valve drops below the vapor pressure. This generates small bubbles, which can then collapse and damage the valve.

Solution: Check whether you are using the correct valve for the pressure and velocity of media in the system. You can also use a multi-stage control valve to slow the pressure drop.

  1. Elastomer damage: Valve seats, gaskets and seals are often made of elastomers (elastic polymer), like Viton® or EPDM. They are generally considered a wear and tear component and require more frequent replacement. This can be exacerbated by media and seal incompatibility.

Solution: Verify that your valve’s elastomer components are compatible with the system media. If necessary, select components of a more compatible material. Three-piece ball valves allow replacement of these components without removing or replacing the entire valve.

  1. Improper valve size: The size of the valve port affects the flow of media, so it’s important to properly calculate valve size according to media flow rate and pipe size. An oversized valve can cause a decrease in pressure, while a ball valve that is too small can cause media bottlenecks and potential explosion. 

Solution: Flow rate calculators for liquids and gasses can tell you what size valve you need depending on the pressure of media in your piping system. Pressure ratings on valves are represented by the Cv value (imperial) or Kv value (metric).

  1. Incorrect installation: A valve that is not properly installed according to the manufacturer’s specifications can cause major disruptions to proper system function.

Solution: Make sure your valves are always installed and serviced by someone with the right training and expertise. When in doubt of proper installation technique, consult the OEM.

  1. Incorrect maintenance and repair: Neglected or improper maintenance can result in damage, workplace hazards, halted production, wasted time and lost revenue.

Solution: Schedule regular preventative maintenance and ensure the technician working on your ball valves and piping system is knowledgeable and experienced. Always follow the manufacturer’s instructions for installation and maintenance.

  1. Improper operational and set pressure differential: When the pressure set by the system operator differs from the actual, operational pressure, it can strain or compromise the valves.

Solution: Check the valve components for damage, wear or leakage, and reset the system pressure accordingly.

  1. Leaks following inactivity: Valves that lie unused for a time can develop blockages, whether from media buildup or parts corrosion.

Solution: Before reactivating a dormant piping system or segment, check that all valves are lubricated and clear of buildup.

  1. Material incompatibility: Certain types of media can erode ball valve bodies or components much faster than others, so it’s important to select the right ball valve materials for your system.

Solution: The ball valve’s product description will tell you what materials it is made of, as well as its ideal applications and media compatibility. A useful tool for this is the Cole-Parmer Chemical Compatibility Database which can be used to ensure valve materials are compatible with specific media. 

  1. Seal or bolt leakage: Damaged elastomer seals or loose nuts and bolts can cause media to leak out of the valve.

Solution: Check whether the elastomer components need to be replaced or if any hardware needs to be tightened.

  1. Particles and sediment buildup: Ball valves are not recommended for media with particulates, but sometimes contamination or sediment buildup occurs regardless. Solid particles can get stuck in the valve, causing damage to the components. The wrong lubrication can also cause valve components to seize.

Solution: Schedule regular inspections and cleanings for all components of your piping system. Always remove debris or buildup from valves to prevent damage or failure. Check with the valve manufacturer before adding any lubrication, to ensure compatibility with valve materials and system media.

  1. Pressure and temperature exceeds required parameters: Pushing a valve beyond its pressure or temperature rating can cause either gradual wear and tear or abrupt valve failure.

Solution: Make sure the valve’s product specifications match the system requirements or conditions.

  1. Valve stem wear: Constant movement of the valve components and a lack of elasticity in the stem packing can contribute to ball valve stem failure.

Solution: The valve stem seal will normally be the first component to fail in a ball valve. If you notice a leak from the valve stem it is time to replace the valve. Alternatively, if you have a three-piece valve you can replace the stem along with the stem seal and hardware.

  1. Water hammer: Abrupt pressure changes in liquid media flow can cause disruptive shock waves to reverberate through a piping system. Known as water hammer, this is one of the leading causes of valve failure in fluid processing systems.

Solution: Throttling valves can minimize water hammer, as can non-slam, slow acting and electrically actuated ball valves. Adding elbows and loops to your piping system design can also reduce the risk.

 

Advantages of Proper Ball Valve Maintenance

Most ball valves are designed to be replaced rather than maintained. One-piece and two-piece ball valves are relatively economical; In automated systems, they can normally be replaced without replacing the actuator, which is the more expensive component. However, for applications with three-piece ball valves, maintaining your ball valves is the proactive way to reduce their risk of failure. If performed regularly and correctly, ball valve maintenance has significant benefits.

Reduced need for shutdowns: With a lower risk of ball valve failure comes a reduced need to shut down production.

Security and safety: Maintenance experts who are properly trained in assessing ball valves can identify potential issues easily and early, thereby lowering your chance of an emergency repair, accident or violation of workplace health and safety standards.

Cost savings: Fewer maintenance issues means more savings. Performing regular inspections and preventative maintenance reduces the risk of unexpected, expensive downtime due to valve failure.

Longevity: Well-maintained valves last longer and require few to no repairs, which helps save money, prevent downtime and keep plant production on schedule.

Keep in mind that some ball valve maintenance can even be performed while the valve is in operation, which allows production to continue uninterrupted.

 

Best Practices for Ball Valve Maintenance

Proper installation and regular and preventative maintenance directly impact your valves’ lifespan. Make sure the technician installing your valves is experienced and knowledgeable in ball valve installation and maintenance, since correct installation reduces the need for repairs or replacement.

As a rule, preventive or predictive maintenance should begin long before any issues arise with your ball valves. A comprehensive ball valve maintenance program should include the following:

Lubrication: The right lubrication prevents parts abrasion, increases the effectiveness of seals and keeps your ball valves operating smoothly. Be sure to choose a lubricant that is compatible with the valve materials and system media; consult the valve manufacturer to confirm whether lubrication is recommended.

Regular cleanings: Clean ball valves simply last longer. To clean three-piece ball valves, remove dust and debris from the interior and exterior of the valve, using cleaning agents that won’t react negatively with the valve materials. Gas-based or compressed air cleaners work well for metal components, and alcohol- or water-based cleaners are ideal for non-metal parts. Be sure to use cleaning agents that are compatible with the valve seal materials.

Routine inspections: Annual ball valve inspections are adequate for most applications, but ball valves in high-cycle and high-pressure environments require more frequent inspections. During scheduled shutdowns, remove ball valves from the piping system, disassemble them, clean the interiors and replace any broken or worn components.

By following these best practices, you will reduce the risk of ball valve failure and even extend the life of your ball valves beyond the manufacturer’s estimate.

 

AUTHOR BIO

George Packard is the vice president of marketing at Gemini Valve, a family-owned American manufacturer of automated and manual ball valves. Established in 1974, Gemini Valve has years of experience in valve design and manufacturing to provide reliable solutions for any type of application.

Maybe you like also

  • Contact Us

    NTGD Valve (China) Co. LTD
    North Avenue Zhuqu Town ,Weishi County, Kaifeng, Henan,P.R.China
    Email: sales@ntgdvalve.com
    Website:www.ntgdvalve.com

    NTGD Valve (UK) Co. LTD
    ADD.: 19,King Street, Gillingham, England ME7 1EO
    Email: sales@ntgd.co.uk