What Cause Check Valve Leakage And How To Fix It?

What are Industrial Valves?

Industrial valves serve as critical tools in diverse industrial applications,facilitating the management of fluid flow,encompassing liquids,gases,and slurries.Their primary function is to regulate,direct,or control the movement of these substances by either opening or closing passages or partially obstructing them.In a simpler context, valves function as gatekeepers,influencing the flow of fluids within a system.These mechanical devices play a pivotal role across various industrial sectors,such as oil and gas,the chemical industry, power plants,water supply,wastewater treatment, and process industries.They are meticulously designed to handle diverse fluid types,providing precise control over their flow.This precision contributes significantly to the overall functionality and safety of industrial operations.

Check valves are used to prevent backflow,ensuring a one-way flow of fluids.It allows fluid to flow in one direction,automatically blocking reverse flow.Check valves are found in various systems,including pumps and water treatment plants.

Here are some common reasons for check valve leakage

Improper Installation:Incorrect installation,such as improper seating or misalignment of the valve,can lead to leakage.To fix this,ensure that the check valve is installed according to the manufacturer's recommendations,with proper alignment and seating.

Damaged Seals or Seats:Wear and tear over time can cause damage to the seals or seats of the check valve,resulting in leakage.To fix this, inspect the seals and seats for signs of damage or wear,and replace them if necessary.Ensure that the replacement seals or seats are compatible with the valve material and specifications.

Foreign Objects or Debris:Accumulation of debris,sediment,or foreign objects in the valve can obstruct the flow path and cause leakage.To fix this,disassemble the check valve and clean the internal components thoroughly.Remove any debris or foreign objects that may be causing obstruction and reassemble the valve properly.

High Pressure or Temperature:Excessive pressure or temperature conditions can put stress on the check valve,leading to leakage.To fix this,consider upgrading to a check valve that is specifically designed to withstand higher pressure or temperature conditions.Alternatively,install pressure or temperature relief devices to mitigate the stress on the valve.

Corrosion or Erosion:Corrosion or erosion of the valve material due to exposure to corrosive fluids can compromise the integrity of the check valve and cause leakage.To fix this,consider using check valves made from corrosion-resistant materials such as stainless steel or bronze.Regular maintenance and inspection can also help identify and address corrosion issues before they lead to leakage.

Faulty Valve Design:In some cases, check valve leakage may be attributed to inherent design flaws or limitations.To fix this,consider replacing the check valve with a different type or design that is better suited for the specific application and operating conditions.

To address check valve leaks,regular maintenance,debris removal,and prompt replacement of damaged components are recommended.

If issues persist, replacing the entire valve may be necessary.

Here's a step-by-step guide on how to fix check valve leakage:

Identify the Source of Leakage:Before attempting to fix the check valve,determine where the leakage is occurring.Inspect the valve and surrounding components for signs of leakage,such as dripping or wet spots.

Check Valve Operation:Verify that the check valve is operating correctly by observing its opening and closing action.Ensure that the valve is not stuck in the open or closed position,as this could contribute to leakage.

Inspect Seals and Seats:Examine the seals and seats of the check valve for signs of damage,wear,or debris accumulation.Replace any damaged or worn seals and seats,and clean out any debris or foreign objects that may be causing obstruction.

Reassemble the Valve:If necessary,disassemble the check valve to access the internal components.Clean the valve thoroughly,paying special attention to the seals,seats,and internal passages.Reassemble the valve carefully,ensuring that all components are properly aligned and seated.

Adjust Valve Installation:Check the installation of the check valve to ensure proper alignment and seating.Adjust the valve if necessary to ensure that it is seated correctly and aligned with the flow direction.

Upgrade Valve Material:Consider upgrading to a check valve made from corrosion-resistant materials,such as stainless steel or bronze,if corrosion is contributing to leakage issues.Choose a valve material that is compatible with the fluid being handled and the operating conditions.

Apply Sealant:In some cases,applying a sealant or thread seal tape to the threads of the check valve can help prevent leakage.Ensure that the sealant is compatible with the valve material and fluid being handled.

Pressure Test:After making any repairs or adjustments to the check valve,perform a pressure test to ensure that the valve is functioning properly and that leakage has been resolved.Monitor the valve closely for any signs of leakage during the pressure test.

Monitor Performance:Regularly monitor the performance of the check valve to ensure that leakage issues do not reoccur.Conduct periodic inspections and maintenance to keep the valve in optimal condition and prevent future leakage.

Check Valve Assembly And Installation Guide

Different modes of check valve failures occur due to improper assembly and installation of the valves.For valves to be installed properly,valve installation rules and guidelines must be followed.Below are three pipe design rules that must be followed for effective installation and operation of check valves:

Pipe Design Rules

Install Check Valves in Non-turbulent (Laminar) Conditions

Pipes connected to the check valves should be designed straight,upstream,and downstream,as valves work best with smooth and non-turbulent (laminar) flow.Five times the nominal pipe size (NPS) of straight pipe is recommended.However,some check valves can be installed with fewer straight pipes.

Properly Calculate Valve Size

For optimum operation of check valves,appropriately sized valves are important.The sizing rules applied to check valves differ from on-off and control valve sizing rules.Nominal valve and nominal pipe sizes should not always be assumed to match,and sizing calculations should be done for minimum,maximum,and normal flow conditions.

Install in the proper orientation

Installing the valve connected to a horizontal or vertical line matters for the smooth operation of the valve.Horizontal lines are usually preferred because of the absence of gravity effect on the valves.Also,even though many valves work when connected to horizontal pipelines,silent or axial flow check valves are best on vertical lines.

Installation Guides

Error in the installation of the valves results in check valve failure and possible damage to the pipe system.Check valves differ in types and parts.Hence installation depends on the check valve type.

However,below are some installation best practices for flapper-type swing check valves:

Check inside the valve to confirm that all material used in transportation and storage has been removed.

Check the operation of the flapper and make sure it operates freely to the seating surface and back.

Confirm that there are no materials at the edges that may cause the valve not to seal properly.

The valve should be installed facing the direction of the flow arrow.Ensure a 3-diameter straight pipe upstream.

If installed vertically,the flow direction must be against gravity (up-flow).

A cover must be on the top of the valve if installed horizontally.

Valves should be inspected and test-run after installation to avoid premature swing check valve failure.

Qualified and licensed professionals should handle the installation of industrial check valves.

Check valve failures can stem from improper installation methods,inadequate maintenance practices,and insufficient research before application.Such failures impede proper valve functioning and may lead to damage to pipe systems,pumps,and well equipment.Check valves,also known as non-return valves,facilitate fluid flow in a single direction, preventing the reverse flow (backflow) in the applied system.Consequently, a check valve failure in a well might result in fluid flowing back into the well.Preventing check valve failures necessitates correct installation, regular testing for early detection of potential issues,and proper maintenance.