QRC Valves

Valve Maintenance

Valves regulate the gases, liquids, and slurries flows in various mechanical applications. They maintain the process control and safety of industrial systems and equipment. However, valves might experience wear, tear, corrosion, or residue build-up over time, leading to leaks, blockages, or failure. Therefore, valve maintenance becomes essential for any facility operation.

Why Do Valves Need Maintenance?

Operational efficiency, longevity, and workplace safety provide three major reasons for valve maintenance.

Regular valve maintenance ensures the valve accurately controls the flow rate, direction, and pressure level. This accuracy ensures efficiency of any plant or equipment, such as petroleum refineries, wastewater treatment plants, and marine hardware. Next, it minimizes the risk of sudden problems in piping systems and reduces unexpected downtime.

Maintenance directly contributes to valve longevity since it prevents premature wear and tear. As a result, you can avoid major repairs and replacement expenses.

Imagine the havoc that a gasoline leak in a refinery would cause. Avoiding these incidents necessitates proactive maintenance to prevent leaks, ruptures, or catastrophic failures of piping systems under pressure.

Much of valve maintenance is predicated on accessibility. Valves are usually set inside the flow path of an active process and removal necessitates the unbolting of flanges and diversion of cessation of a fluid’s flow path. Such an action may not be desirable or possible. Oftentimes, visual inspection may be the only available option.

Gate Valve Maintenance

A gate valve opens the flow in a piping system by lifting a rectangular or round gate in the path of the fluid. It is commonly found in applications requiring a free flow or minimal restriction.

A standard gate valve maintenance process includes the following steps:

    • A thorough visual inspection for any signs of wear, corrosion, or leaks.

    • Checking bolt integrity and ensuring correct valve alignment.

    • Based on the manufacturer’s guidelines, lubricate the valve stem and moving parts.

    • Identify whether there is any sealing surface damage and debris or not. If yes, assess the required disassembly for cleaning or repair.

    • Clean all gate valve components with appropriate tools to remove dirt, rust, or scale. Check the valve seat and gate for erosion, damage, repair, or replacement parts.

Furthermore, gate valves might involve a packing gland in some applications, like chemical processing plants. If so, inspect for wear or leakage. Then, adjust or replace the packing material accordingly.

Globe Valve Maintenance

Like every other valve, the globe valve demands regular inspection to identify the necessity of maintenance. It could be anything from inspection of wear & tear, weeping around the valve body, or leakage. On the other hand, regular maintenance includes adjusting the packing gland bolts, lubrication, checking valve seats and discs, etc.

Issues in OperationPotential CausesMaintenance or Repair ActionTypical Application
Flow LeakageWorn or damaged packing, loose bonnet bolts, or improper seatingReplace packing, tighten bonnet bolts, and reseat valveAggressive slurry transport
Stiff OperationSediment build-up, stem corrosion, and lack of lubricationClean and lubricate moving parts & valves, and replace if any part is corrodedWater treatment plants
Incomplete ClosureWear on disc or seat and misalignmentResurface or replace seat/disc and realign valve componentsTypical with valves regulating high-pressure steam.
Corrosion/DamageCorrosion due to harsh fluids or environment, and mechanical damageReplace if parts are damaged, apply protective coatingsValves exposed to saline environments, such as marine applications.
Abnormal NoiseLoose internal components, cavitation, flow turbulenceAdjust internal components, check flow rates, and look for cavitationNoise issues in valves controlling heating or cooling flow in an HVAC system.

Gate Valve Issues and Troubleshooting

Check Valve Maintenance

A check valve permits passage in one direction while automatically preventing reverse flow. For example, a check valve automatically closes against excessive downstream pressure for the uni-directional flow of gases in oil refinery piping.

Periodic maintenance includes cleaning, lubrication, and testing flow and back-flow pressure.

Here are troubleshooting actions to ensure optimal performance during operation:

    • Check that the installation aligns with the flow and ensure a recommended pressure to activate the valve.

    • Visually verify that no obstructions exist within the valve, such as sediment, residue, or debris.

    • Examine the valve sealing areas for wear or damage to check valve closing issues.

    • If any parts (disc, seat, spring, hinge pin, etc.) have noticeable wear or damage, replace them.

Butterfly Valve Maintenance

These valves can range from fully open to fully closed, regulating, or throttling the fluid flow in large pipes with limited space conditions. Butterfly valves are especially popular in high-performance areas like energy plant equipment and HVAC systems. Meanwhile, a lack of valve maintenance can lower the downtimes or even equipment failure.

Regular maintenance of a butterfly valve includes the following:

    • Cleaning and lubrication

    • Seal and gasket replacement

    • Verification of torque required for operation.

    • Checking the hydraulic or pneumatic pressures and electrical system associated with the actuator.

Despite regular maintenance, a butterfly valve might face sudden operational issues like leakage, sticking, binding, insufficient flow control, and excessive torque. Removing the obstruction, replacing the worn parts, correcting adjustments on parameters, and fixing alignment solves these problems. A savvy operator should fix the problem based on the root causes. 

Plug Valve Maintenance

A plug valve controls the fluid flow with a cylindrical or conically tapered “plug”. This plug rotates and regulates the flow through the valve. Subsequently, plug valves require periodic maintenance to maintain functionality and optimal performance.

Here are the plug valve activities:

    • Clean the plug valve components and apply correct lubrication fittings like giant button heads or lube stick injection.

    • Consequently, apply lube to the plug and other moving parts.

    • Monitor the wear and tear on parts. Then repair or replace accordingly.

    • Check the condition of the sealant and how much pressure it bears.

However, several other troubleshooting actions are necessary to handle potential plug valve issues in any system or equipment.

Specific IssueCauseTroubleshooting
Sticking or Hard OperationDebris, lack of lubrication, and corrosionClean the valve internals, lubricate, and replace corroded parts
Leakage From the ValveWorn seals, incorrect plug alignment, and valve seat erosionReplace seals/valve seat and realign plug
The Problem in Complete ShutoffMisaligned/worn plug, worn valve seat, and debris obstructionRepair/replace the plug and valve seat, clean debris, repair/replace valve seat
Excessive WearRapid cycling, abrasive flow, and unsuitable valve sizingReview application specifications, use wear-resistant materials, and maintain proper sizing

Plug Valve Issues and Troubleshooting

Ball Valve Maintenance

A rotating spherical ball with a bore inside regulates the flow in a ball valve. Meanwhile, the shaft connected to this ball and seat controls the ball’s movement.

General ball valve maintenance includes:

    • Inspection of wear, tear, corrosion, and other damages.

    • Ensuring accurate positioning and alignment.

    • Performing pressure testing to identify the leakage.

On the other hand, the following are the potential problems that might arise during the continuous operation of ball valves.

LeakageWorn stem seals or O-rings, corrosion, or damageReplace seals/O-rings, tighten packing gland
Ball DamageCorrosion or physical damageReplace the ball, ensure the ball is made with corrosion-resistant materials
Improper Ball AlignmentMisalignment of the ball within the valveSet the correct ball alignment
Handle Breakage or WearPhysical wear or improper handlingChange handle, ensure proper attachment
Excessive Torque RequirementsUnsuitable sizing, internal obstructionsCheck valve size, clear obstructions

Ball Valve Issues and Troubleshooting

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