In domestic applications, a gate valve is used to turn off the gravity-fed water supply temporarily during repairs. But sometimes, it may be dysfunctional and start leaking for various reasons, such as the valve not being fully closed due to debris, dirt, or other substances. But the other times, it may be because the valve seat or seal is damaged.

Click here to get more.

A leaking industrial gate valve can expose the industrial or domestic pipelines to risks. So it is essential to find a reliable solution to make it operate before it is too late.

In this blog, we will learn everything about inspecting leakage in a gate valve and different ways to avoid and fix it. It is vital to immediately fix a malfunctioning gate valve caused by the mineral build-up by fully opening and closing it every few months. It helps clear any potential problems in the device while allowing the users to make the most out of it without hindrances.

Since it is not so difficult to repair a gate valve leakage, one must consider doing it on their own.

Please Check Beforehand:

Source: Deposit Photos

Here are a few things to check in a gate valve before performing any kind of repairing work on it.

Proper Gate Valve Type:

A gate valve controls gas and liquid flow in almost every process and system. But choosing the right one is equally crucial. One can begin the selection process by gathering some basic information on system performance requirements as it makes finding a valve easier.

Here are four tips for learning how to match the features of a gate valve with the requirements:

• Tip 1: Valve Size and Type

An ideal wholesale actuated gate valve for an industrial or domestic pipeline application should be able to perform a few critical functions, such as shut-off flow, diver flow, mix flow, backflow prevention, adjusting the flow, and pressure relief. Besides, its size must match the expected flow through the system.

• Tip 2: Material Construction

It is essential to learn about the chemical compatibility requirements of a valve. Its material must be compatible with the gases or liquids flowing through it. If it is built of plastic, it will resist harsh or corrosive chemicals much better than the ones made of metal.

• Tip 3: Performance Needs

When purchasing a gate valve for a particular application, one must determine its pressure range and temperature requirements. Valves made of metal can withstand higher pressures and temperatures better than plastic ones. They are also suitable for pressurized gases because they have a sturdier build.

• Tip 4: Maintenance Needs

Any valve choice must include attention to maintenance needs for both application stability and device reliability. The connection type of a particular China electric knife gate valve significantly affects its repair or replacement speed or ease. Whether its connection is threaded, barbed, or push-in, each has its pros and cons.

Leakage Tolerance:

Gate valve leakage is a common occurrence in industrial settings. Even the valves labeled as 0 leakages or bubble-tight are not necessarily completely leakage-free. Let&#;s explore the types and common causes of gate valve leakages!

The two main types of valve leakages include fugitive emissions and the ones that remain in a piping system. Fugitive emissions are leaked into the atmosphere, causing environmental and safety hazards. On the other hand, leakages in the piping system also pose potential safety risks.

Common causes of a pneumatic gate valve leakage include:

• It is not being fully closed due to dirt, debris, or other obstruction
• Its seat or seal is damaged
• is of the wrong size for a certain project, and
• It is not designed to close 100%, which means it does not have excellent on/off capabilities.

The API (American Petroleum Institute) has set acceptable liquid and gas testing leakage rates. According to API standard 598, all gate valves should meet the leakage criteria before shipment from the manufacturer to the industry. In the case of liquid fluid, there shall be no evidence of drops on the external surface. If it is gas, no leakage shall be revealed by a detection method.

According to section 5 of the pressure testing of steel gate valve test, a leakage rate of 10 cc/hr per inch of nominal pipe diameter is permissible in a gate valve.

Operating Pressure Limit:

In industrial pipelines, a gate valve is used for a range of applications, either above-ground or underground. Since it can fully open or close, it functions as an isolating valve. When operating this valve, either clockwise or anti-clockwise, its gate moves upwards or downwards on the threaded part of the stem.

A gate valve is often used where minimum pressure loss and a free bore are required. When fully open, it has no obstruction in the flow path, resulting in a low-pressure loss. Since it is multi-turn, its operation is done by a threaded stem. Its slow operation helps prevent water hammer effects as it turns multiple times to an open or close position.

One can use a gate valve for a vast number of fluids. In potable water, wastewater, and neutral water, the temperature should be between -20 and +70 degrees C, maximum of five m/s flow velocity and up to 16 bar differential pressure. In gaseous working conditions, the temperature should lie between -20 and +60 degrees C, with a maximum 20 m/s flow velocity and up to 16 bar differential pressure.

If the pressure rating is 150 at 100 degrees Celsius, the valve can withstand 150 PSI at 100 degrees Celsius.

Common Gate Valve Leakage and Solutions:

Source: Deposit Photos

Gate valves are the main components of the industrial pipeline. But it faces several faults, giving the users a tough time. Here are some common gate valve leakages and their easy solutions:

Leakage Between Actuator and Valve

Description: In an industrial pipeline, a regulator is the primary type of actuator. It receives the control signal of the unit output with the help of a dynamic operation to change the fluid flow. A gate valve &#;includes an actuator and a valve further divided into electric, hydraulic, and pneumatic, depending on the actuator&#;s power.

In the modern factory automation control system, a hydraulic actuated gate valve receives a control signal to realize the regulation of the chemical process as a terminal actuator of the automation regulation system. Its motion sensitivity directly depends on the quality of the regulating system. But, about 70% of the fault is caused by the leakage between the actuator and the valve.

Possible cause: Some of the most common reasons causing leaks between the actuator and a gate valve include stem length discomfort. When the length of the stem is too long or short, it results in a gap between the seat and the spool. Thus, they cannot contact fully, resulting in lax closure and internal leakage.

Similarly, when the valve stem of the air closing valve is too short, it results in a gap between the gate valve backseat test and its core. It too fails to contact entirely, causing loose closing and, thus, internal leaks.

How to Fix: To fix the leakage issue between an actuator and the gate valve, one should strictly control the force but not through a hard twist. It is equally vital to improving the processing quality to meet the specification requirements. Some common steps include using the devices carefully, maintaining the normal lubrication state, straightening or fixing the stem nut, and revising or updating it to meet the standard specifications.

One must also regularly clean the dust on the stem nut, lest rust and cover the valve stem of the outdoor gate as it also needs protection.

Shut-off Failure

Description: It is essential to shut off a gate valve completely if maintenance or plumbing repairs are to be done. But sometimes, if the main control valve is a gate type, it may fail to close rightly.

In such situations, a little water will continue to flow even after a gate valve is closed completely. Since it is a significant problem, some people may try exerting an additional force on the handle, causing permanent damage to the device and a loss of water supply.

Possible cause: After a certain period of continued usage, users may find that the dirt or scale build-up on a gate valve becomes common and frequent. It is not a good sign because it causes problems with the closing mechanism.

Sometimes, the issue is also caused by seizing the gate valves. When dirt or deposits get between the operation of a stainless 3 way ball valve, it may seize up. It happens when the water flowing around the piping system includes scales and iron deposits that &#;stick to rough patches of the valve, thus causing the mechanism to jam.

How to Fix: Because of prolonged usage, a gate valve may keep the closing mechanism from shutting off properly. Fortunately, fixing the issue by replacing the valve or cleaning it is possible. People who replace their valves because the issue persists should remember that they do not always have to drain down, as long as they have the experience and tools to do so.

If sediment or mineral deposits are preventing the gate from shutting off properly, one must flush out the inside of it. The right way to do so is to open a faucet on a sink to mimic the flow of water and then gently and repeatedly open and close the valve. If the handle fails to turn freely, loosen the packing nut above the valve body and around the stem.

Repeat lowering its gate routinely to break free the sediment and flush it away with a water flow.

Leaks When Closing

Description: Gate valves are usually used as the main supply valves in houses. They are often installed in spots where a washer might harden, decay, or become dislodged over a long period of use. But it does not mean gate valves cannot develop problems if kept neglected.

Sometimes, a gate valve may break even in the closed position, requiring a lot of repair work. It is a tricky and dangerous task as changing the valve under water pressure is tough, especially if electric services are nearby.

Possible cause: Some users might experience leakages while closing a valve gate to shut off the water flow. In most cases, it happens due to small bits of debris in the liquid medium. As most supply valves are left open, debris may build up, causing damage to the valve and leakages even when closed.

How to Fix: If a gate valve starts leaking in the closed position, it can be raised back up to restore water service. Drill a small hole near the bottom of the valve body in line with the gate using a sharp object.

After pushing the gate of a top entry floating ball valve, insert a like-sized sheet metal screw into the hole to stop the water flow.

BSTV contains other products and information you need, so please check it out.

Leaks From Seat or Seal

Description: The seat or seal of an industrial gate valve is always in direct contact with the fluid and gas medium flowing in the pipeline. It makes the valve vulnerable to any corrosive elements that may be present in the medium. It causes the sealing or seating of the gate valve to fail after it has reached its service life threshold.

Possible cause: The building up of deposits and dirt around the gate valve seat or seal causes displacement in the device. It further leads to leakages in the gland, nut, and olive area and the connecting part of the main valve body.

Sometimes, burnout of the sealing or seating surface also occurs when the flushing fluid is insufficient, or there is excess heat inside the seal cavity. A few root causes of inadequate sealing flushing include the pump cavity medium cut-off, damage to the ring, and sudden pressure drop in the chamber.

How to Fix: If the build-up of sediments and dust in a gate valve causes leaks from the seat and seal, the user must take steps to fix the problem. The simplest way to fix it is by tightening the nut near the gland. But if this trick fails to work, one may also try unscrewing and placing a thread or using a new washer near the seating area.

Leaks From Stem

Description: Sometimes, a new gate valve may leak near the handle or stem area when turned on. It is a common phenomenon during the installation or maintenance of the valves, which requires an immediate fix as it may damage the device over time.

Possible cause: The most common causes of a leak from the stem of a gate valve are wear and corrosion of the wedge and seat. The inner parts of a valve tend to wear over time, causing the wedge to stick in the open or closed position. When pressure is placed upon the handwheel, the steam leading from it to the wedge may break off, rendering the valve useless.

How to Fix: To repair a gate valve leaking from stem, tighten the packing nut one-eighth to one-quarter turn using a wrench. One may do so by shutting off the water to the leaking valve. The next step is removing the handle from the stem and loosening and removing a packing nut. Replace the old washer with the new one. Reinstall the packing nut by tightening it lightly with a wrench and re-attaching the handle.

But remember not to over-tighten it. Switch on the water, open the repaired valve, and check for leaks. If it is still leaking, tighten the packing nut one-eighth of a turn at a time until it stops.

Working Conditions For a Gate Valve:

Source: Deposit Photos

The working of a gate valve is similar to any other valve type. To open it, one needs to turn the handwheel which moves the gate up or down on the stem through the threads. This valve needs more than 360 degrees to turn to open or close entirely.

When the gate lifts, it opens the inlet to the outlet, allowing the unobstructed passageway for the media to flow. When the gate of a water lug butterfly valve lowers, it closes and blocks the media flow.

There is a non-linear relationship between the gate valve&#;s vertical travel and the flow rate, with the most significant changes occurring near the complete closure. Its relatively high velocity at partial opening causes gate and seat wear when it is used to regulate the flow. It, along with possible gate vibrations, shortens the valve&#;s service life. That is why it should only be used for on or off controls.

As this multi-turn valve turns open or closes multiple times, its slow operation helps prevent water hammer effects. This gate valve testing standard is used for a vast number of fluids under the following working conditions:

• Potable water, wastewater, and neutral liquids: Temperature must be between -20 and +70 °C, with a maximum of five m/s flow velocity and up to 16 bar differential pressure. 
• Gas: Temperature should lie between -20 and +60 °C, with a maximum 20 m/s flow velocity and up to 16 bar differential pressure.

Storage Conditions For a Gate Valve:

Source: Deposit Photos

A gate valve is made using a variety of materials and seat types. These devices are easy to use and long-lasting if installed and maintained correctly. However, their installation techniques vary slightly for different end connections, but the other instructions remain the same.

Like any other industrial equipment, it is essential to store a valve under ideal storage conditions to keep it from wearing before time and spending money on gate valve repair. People wishing to make the most out of this device should keep it in a cool and well-ventilated space if stored for an extended period. But doing this much is not enough.

To protect the seat and seals of a hydraulic lift valve, it is suggested not to unpack it until they are ready for installation. By doing this, people preserve the valve from catching dust and debris, which may eventually cause seat leakage and thus cause the device to malfunction.

Maintenance Tips:

Source: Deposit Photos

To continue using a valve for a long time, it is necessary to look after its maintenance. One may achieve it by operating each valve in suitable temperature conditions. To let a valve function properly, adjust it to the ideal temperature, depending on the material type.

• Brass: Valves made of brass must not be used under temperatures above 450 degrees F as they may damage under such conditions.
• Iron: Valves made of iron should also not be used under temperatures greater than 450 degrees F.
• Stainless steel or White Iron: A high pressure stainless steel ball valve is suitable for conditions with low temperatures. In contrast, a corrosive flow valve must not be used in high temperatures.
• Stell Steel: Valves made using this material are suitable for high temperature and high-pressure working conditions.

Some other essential maintenance tips for a gate valve include the following:

• If the gate valve is not used regularly, cycle it at least once a month.
• Before performing any maintenance work, relieve the system pressure.
• Reverse the installation of a gate valve testing procedure to remove debris from the pipelines.
• When replacing the valve, remove its top body (bonnet) and stem. Screw out the gate to replace it with the new one. Install the entire body and refit into the line.

The Bottom Line:

Source: Deposit Photos

We hope this blog helps everyone learn everything about gate valve leakage, from its inspection to avoidance and fixing. Since this device is available in multiple designs and materials to offer effective sealing for different applications, it should be taken care of. If the users do not provide it with proper maintenance, it may malfunction after a certain period.

If a gate valve starts leaking, the best thing to do is to replace it with a new one. Please contact us to purchase the most trustable and long-lasting gate valves in the market.

A Comprehensive Guide to Gate Valve Uses and Repair

Figure 1: Gate valve

A gate valve allows the media to flow through freely or stops the fluid flow completely. Gate valves are used in the power, waterworks, wastewater, pipeline, oil and gas production industries, and commercial buildings. When undertaking new installations, maintenance, or repair works, gate valves help isolate certain areas in the water supply network or reroute fluid flow to desired pipeline sections. Gate valves can sometimes get damaged. The following guide discusses case scenarios of when these valves might need repair and the steps to make repairs.

Table of contents

View our online selection of gate valves!

• Gate Valves

What is a gate valve?

Gate valves are control valves used to shut off fluid flow completely or provide unobstructed flow within a pipeline. A gate valve consists of a valve body, gate, seat, stem, gasket, and a wheel for operating the valve, as seen in Figure 2. The gate and seat together perform the function of shutting off fluid flow. Read our article on gate valves for more information on a gate valve&#;s working principle and the various types of gate valves.

Figure 2: Gate valve cross section: gate valve (A), handwheel (B), stem (C), gasket (D), bonnet (E), valve body (F), and flange (G).

Gate valve issues

Several issues can affect gate valves. Handling each problem effectively helps avoid further complications. The most common causes of gate valve failure are corrosion and general wear and tear over time. The following sections summarize some of the main challenges gate valves face and how to troubleshoot and fix them.

Gate valve fails to close

Troubleshooting

A gate valve can fail to close as expected when sediment builds up inside its body. Sediment buildup occurs mainly when the gate valve operates fully open for a longer time than expected, causing dirt to build up at the sides and preventing its closure. The sediments get stuck between the gate and valve&#;s interiors when the gate lowers, causing problems.

How to fix the problem

1. Start by closing the gate valve as far as possible. Please note that excessive pressure should not be applied during this step.
2. Open a sink faucet to flush debris out of the system.
3. Open the gate valve as far as possible.
4. Repeat the opening and closing cycle until the gate seats altogether, or the gate stops making any progress towards closing. This action usually breaks loose and flushes any built-up debris out of the valve. If the valve doesn&#;t show downward progress without shutting off the water flow, it needs to be taken out for evaluation. Switch to Step 5 if this happens.
5. Shut off the water supply and remove the gate valve.
6. Use a wrench to remove the valve housing from the top. Ensure not to loosen the packing nut that holds the packing and prevents water from leaking around the handle.
7. Evaluate the outer edges of the gate and scrape off any deposits before reassembling the valve.
8. Slide the gate back into its guide and tighten the top of the valve housing using a wrench.
9. Turn on the water supply and test the valve again.
10. Replace the valve if it is severely corroded or filled with debris.

Gate valve stuck

Another common challenge with gate valves is that they can get stuck. The gate valve can be seized open or closed, due to which it cannot perform its function correctly.

Troubleshooting a stuck gate valve

Perform the following steps before checking a stuck gate valve:

1. Stop the water flow to understand the problem better.
2. Isolate your working area to avoid the adverse effects of further leaks.
3. Examine the area to understand whether there are external factors that cause the problem, like excess cold or a damaged water line. Wear and corrosion can also prevent gate valves from opening.
4. Place a container under the damaged valve to drain the excess water (in case the gate valve is seized open) before removing or fixing it.

How to fix a stuck gate valve

1. Clean any atmospheric deposits from the gate valve threads.
2. Apply 3-in-one or penetrating oil to the gate valve. Wipe the excess oil with a rag and ensure that the oil reaches the valve's threads.
3. Tap the valve handle with a hammer to check if the valve changes position from open to closed.
4. Attach an adjustable wrench or channel lock on the valve handle. It is advisable to wear gloves while working to avoid slipping and ensure a stable working surface.
5. Warm the handle using a hair drier or blow torch.
6. Turn the valve handle to check if it changes the valve position.

Gate valve leaking from stem

Old and new valves can leak around the stem section, mainly when the valve handle is turned to open or close the valve. Several reasons can cause this leakage: not often fully closing the valve, damage to the valve, poor design, and using the wrong size gate valve.

Troubleshooting

1. Tightening: Turn the gate valve handle to check if the leakage is caused by the valve failing to close. Gate valves fail to close fully when sediment builds up inside the valve's body.
2. Damaged valve stem: Check whether the valve&#;s stem area has been damaged. Wear and corrosion are the most common causes of such damage.
3. Check the design and valve size: Ensure that the valve stem is compatible and designed for your specific valve. If not, replace the valve stem.

How to fix the problem

1. Tighten the packing nut. The packing nut makes a strong watertight seal where the valve stem meets the water line. So, if there is a leak at the valve stem, it likely means the valve is not completely stopping the flow. Hence, the first step you should do to stop the leak is to tighten the packing nut.
2. Replace the valve stem packing material or washer. When the gate valve&#;s packing nut is tightened, it confines the packing material against the washer to prevent any water from passing through. This packing material hardens over time, forming a solid seal that causes the valve to leak. In this case, it is better to replace the stem packing material, which can be found at most hardware stores.

How to take apart a gate valve for repair

Perform the following steps to take apart a gate valve for repair:

1. Turn off the main water supply.
2. Detach the valve from the pipes by unbolting the flanged ends.
3. Loosen the valve bonnet using pliers. Do not loosen the packing nut because this part ensures that there are no leaks in the stem.
4. Remove the valve's top to separate the seating and handle from the body.

You can now examine each part for possible faults. Use a cleaning tool such as a toothbrush to clean each valve part. If there are any faults, replace the affected parts; else, start the rebuilding process. When rebuilding, place the gate in the appropriate position in the valve's body, then screw the bonnet until it is secure. Now turn the handle to see if the valve is working. The gate should be able to open and close fully. If all is well, place the valve back on the pipeline.

Note: It is advisable to use industrial valve sealant tape to put the valve back in the pipeline.

Replacing a gate valve with a ball valve

Always go for ball valves rather than gate valves whenever possible. Ball valves are generally more effective, although they are more expensive. Ball valves form a tighter seal when closed, and they are more reliable and durable than gate valves. Perform the following steps to replace a gate valve with a ball valve:

1. Heating up: Before replacing the gate valve, get a torch to heat the parts (valve joints and handle stem) for removal.
2. Turn off the water: Drain the water from the pipes by turning it off. Then, open the gate valve and heat the valve joints.
3. Use channel locks: Grab the valve with a hammer to see whether it moves. If it does, it is hot enough. If it does not move, apply heat on adjacent elbows and some lateral pressure.
4. Final installation: Now install the ball valve.

Read our gate valve vs ball valve article for a thorough comparison between both valve types.

FAQs

Are ball valves better than gate valves?

Yes, ball valves have less response time and better sealing properties than gate valves.

Which tools should I keep in my gate valve repair kits?

Get a seat removal tool, a screwdriver, and a wrench set.

Can gate valves fail?

Yes, gate valves can fail due to wear and corrosion and must be troubleshot for possible faults.

Why is my gate valve leaking?

The gate valve can leak due to the lack of complete closure, damage, poor design, or the use of the wrong size with its application.

View our online selection of gate valves!

• Gate Valves

  Gate Valve Leakage: Inspect, Avoid, and How to Fix

  In domestic applications, a gate valve is used to turn off the gravity-fed water supply temporarily during repairs. But sometimes, it may be dysfunctional and start leaking for various reasons, such as the valve not being fully closed due to debris, dirt, or other substances. But the other times, it may be because the valve seat or seal is damaged.

  A leaking industrial gate valve can expose the industrial or domestic pipelines to risks. So it is essential to find a reliable solution to make it operate before it is too late.

  In this blog, we will learn everything about inspecting leakage in a gate valve and different ways to avoid and fix it. It is vital to immediately fix a malfunctioning gate valve caused by the mineral build-up by fully opening and closing it every few months. It helps clear any potential problems in the device while allowing the users to make the most out of it without hindrances.

  Since it is not so difficult to repair a gate valve leakage, one must consider doing it on their own.

  Please Check Beforehand:

  Source: Deposit Photos

  Here are a few things to check in a gate valve before performing any kind of repairing work on it.

  Proper Gate Valve Type:

  A gate valve controls gas and liquid flow in almost every process and system. But choosing the right one is equally crucial. One can begin the selection process by gathering some basic information on system performance requirements as it makes finding a valve easier.

  Here are four tips for learning how to match the features of a gate valve with the requirements:

  • Tip 1: Valve Size and Type

  An ideal wholesale actuated gate valve for an industrial or domestic pipeline application should be able to perform a few critical functions, such as shut-off flow, diver flow, mix flow, backflow prevention, adjusting the flow, and pressure relief. Besides, its size must match the expected flow through the system.

  • Tip 2: Material Construction

  It is essential to learn about the chemical compatibility requirements of a valve. Its material must be compatible with the gases or liquids flowing through it. If it is built of plastic, it will resist harsh or corrosive chemicals much better than the ones made of metal.

  • Tip 3: Performance Needs

  When purchasing a gate valve for a particular application, one must determine its pressure range and temperature requirements. Valves made of metal can withstand higher pressures and temperatures better than plastic ones. They are also suitable for pressurized gases because they have a sturdier build.

  • Tip 4: Maintenance Needs

  Any valve choice must include attention to maintenance needs for both application stability and device reliability. The connection type of a particular China electric knife gate valve significantly affects its repair or replacement speed or ease. Whether its connection is threaded, barbed, or push-in, each has its pros and cons.

  Leakage Tolerance:

  Gate valve leakage is a common occurrence in industrial settings. Even the valves labeled as 0 leakages or bubble-tight are not necessarily completely leakage-free. Let&#;s explore the types and common causes of gate valve leakages!

  The two main types of valve leakages include fugitive emissions and the ones that remain in a piping system. Fugitive emissions are leaked into the atmosphere, causing environmental and safety hazards. On the other hand, leakages in the piping system also pose potential safety risks.

  Common causes of a pneumatic gate valve leakage include:

  • It is not being fully closed due to dirt, debris, or other obstruction
  • Its seat or seal is damaged
  • is of the wrong size for a certain project, and
  • It is not designed to close 100%, which means it does not have excellent on/off capabilities.

  The API (American Petroleum Institute) has set acceptable liquid and gas testing leakage rates. According to API standard 598, all gate valves should meet the leakage criteria before shipment from the manufacturer to the industry. In the case of liquid fluid, there shall be no evidence of drops on the external surface. If it is gas, no leakage shall be revealed by a detection method.

  According to section 5 of the pressure testing of steel gate valve test, a leakage rate of 10 cc/hr per inch of nominal pipe diameter is permissible in a gate valve.

  Operating Pressure Limit:

  In industrial pipelines, a gate valve is used for a range of applications, either above-ground or underground. Since it can fully open or close, it functions as an isolating valve. When operating this valve, either clockwise or anti-clockwise, its gate moves upwards or downwards on the threaded part of the stem.

  A gate valve is often used where minimum pressure loss and a free bore are required. When fully open, it has no obstruction in the flow path, resulting in a low-pressure loss. Since it is multi-turn, its operation is done by a threaded stem. Its slow operation helps prevent water hammer effects as it turns multiple times to an open or close position.

  One can use a gate valve for a vast number of fluids. In potable water, wastewater, and neutral water, the temperature should be between -20 and +70 degrees C, maximum of five m/s flow velocity and up to 16 bar differential pressure. In gaseous working conditions, the temperature should lie between -20 and +60 degrees C, with a maximum 20 m/s flow velocity and up to 16 bar differential pressure.

  If the pressure rating is 150 at 100 degrees Celsius, the valve can withstand 150 PSI at 100 degrees Celsius.

  Common Gate Valve Leakage and Solutions:

  Source: Deposit Photos

  Gate valves are the main components of the industrial pipeline. But it faces several faults, giving the users a tough time. Here are some common gate valve leakages and their easy solutions:

  Leakage Between Actuator and Valve

  Description: In an industrial pipeline, a regulator is the primary type of actuator. It receives the control signal of the unit output with the help of a dynamic operation to change the fluid flow. A gate valve &#;includes an actuator and a valve further divided into electric, hydraulic, and pneumatic, depending on the actuator&#;s power.

  In the modern factory automation control system, a hydraulic actuated gate valve receives a control signal to realize the regulation of the chemical process as a terminal actuator of the automation regulation system. Its motion sensitivity directly depends on the quality of the regulating system. But, about 70% of the fault is caused by the leakage between the actuator and the valve.

  Possible cause: Some of the most common reasons causing leaks between the actuator and a gate valve include stem length discomfort. When the length of the stem is too long or short, it results in a gap between the seat and the spool. Thus, they cannot contact fully, resulting in lax closure and internal leakage.

  Similarly, when the valve stem of the air closing valve is too short, it results in a gap between the gate valve backseat test and its core. It too fails to contact entirely, causing loose closing and, thus, internal leaks.

  How to Fix: To fix the leakage issue between an actuator and the gate valve, one should strictly control the force but not through a hard twist. It is equally vital to improving the processing quality to meet the specification requirements. Some common steps include using the devices carefully, maintaining the normal lubrication state, straightening or fixing the stem nut, and revising or updating it to meet the standard specifications.

  One must also regularly clean the dust on the stem nut, lest rust and cover the valve stem of the outdoor gate as it also needs protection.

  Shut-off Failure

  Description: It is essential to shut off a gate valve completely if maintenance or plumbing repairs are to be done. But sometimes, if the main control valve is a gate type, it may fail to close rightly.

  In such situations, a little water will continue to flow even after a gate valve is closed completely. Since it is a significant problem, some people may try exerting an additional force on the handle, causing permanent damage to the device and a loss of water supply.

  Possible cause: After a certain period of continued usage, users may find that the dirt or scale build-up on a gate valve becomes common and frequent. It is not a good sign because it causes problems with the closing mechanism.

  Sometimes, the issue is also caused by seizing the gate valves. When dirt or deposits get between the operation of a stainless 3 way ball valve, it may seize up. It happens when the water flowing around the piping system includes scales and iron deposits that &#;stick to rough patches of the valve, thus causing the mechanism to jam.

  How to Fix: Because of prolonged usage, a gate valve may keep the closing mechanism from shutting off properly. Fortunately, fixing the issue by replacing the valve or cleaning it is possible. People who replace their valves because the issue persists should remember that they do not always have to drain down, as long as they have the experience and tools to do so.

  If sediment or mineral deposits are preventing the gate from shutting off properly, one must flush out the inside of it. The right way to do so is to open a faucet on a sink to mimic the flow of water and then gently and repeatedly open and close the valve. If the handle fails to turn freely, loosen the packing nut above the valve body and around the stem.

  Repeat lowering its gate routinely to break free the sediment and flush it away with a water flow.

  Leaks When Closing

  Description: Gate valves are usually used as the main supply valves in houses. They are often installed in spots where a washer might harden, decay, or become dislodged over a long period of use. But it does not mean gate valves cannot develop problems if kept neglected.

  Sometimes, a gate valve may break even in the closed position, requiring a lot of repair work. It is a tricky and dangerous task as changing the valve under water pressure is tough, especially if electric services are nearby.

  Possible cause: Some users might experience leakages while closing a valve gate to shut off the water flow. In most cases, it happens due to small bits of debris in the liquid medium. As most supply valves are left open, debris may build up, causing damage to the valve and leakages even when closed.

  How to Fix: If a gate valve starts leaking in the closed position, it can be raised back up to restore water service. Drill a small hole near the bottom of the valve body in line with the gate using a sharp object.

  After pushing the gate of a top entry floating ball valve, insert a like-sized sheet metal screw into the hole to stop the water flow.

  Leaks From Seat or Seal

  Description: The seat or seal of an industrial gate valve is always in direct contact with the fluid and gas medium flowing in the pipeline. It makes the valve vulnerable to any corrosive elements that may be present in the medium. It causes the sealing or seating of the gate valve to fail after it has reached its service life threshold.

  Possible cause: The building up of deposits and dirt around the gate valve seat or seal causes displacement in the device. It further leads to leakages in the gland, nut, and olive area and the connecting part of the main valve body.

  Sometimes, burnout of the sealing or seating surface also occurs when the flushing fluid is insufficient, or there is excess heat inside the seal cavity. A few root causes of inadequate sealing flushing include the pump cavity medium cut-off, damage to the ring, and sudden pressure drop in the chamber.

  How to Fix: If the build-up of sediments and dust in a gate valve causes leaks from the seat and seal, the user must take steps to fix the problem. The simplest way to fix it is by tightening the nut near the gland. But if this trick fails to work, one may also try unscrewing and placing a thread or using a new washer near the seating area.

  Leaks From Stem

  Description: Sometimes, a new gate valve may leak near the handle or stem area when turned on. It is a common phenomenon during the installation or maintenance of the valves, which requires an immediate fix as it may damage the device over time.

  Possible cause: The most common causes of a leak from the stem of a gate valve are wear and corrosion of the wedge and seat. The inner parts of a valve tend to wear over time, causing the wedge to stick in the open or closed position. When pressure is placed upon the handwheel, the steam leading from it to the wedge may break off, rendering the valve useless.

  How to Fix: To repair a gate valve leaking from stem, tighten the packing nut one-eighth to one-quarter turn using a wrench. One may do so by shutting off the water to the leaking valve. The next step is removing the handle from the stem and loosening and removing a packing nut. Replace the old washer with the new one. Reinstall the packing nut by tightening it lightly with a wrench and re-attaching the handle.

  But remember not to over-tighten it. Switch on the water, open the repaired valve, and check for leaks. If it is still leaking, tighten the packing nut one-eighth of a turn at a time until it stops.

  Working Conditions For a Gate Valve:

  Source: Deposit Photos

  The working of a gate valve is similar to any other valve type. To open it, one needs to turn the handwheel which moves the gate up or down on the stem through the threads. This valve needs more than 360 degrees to turn to open or close entirely.

  When the gate lifts, it opens the inlet to the outlet, allowing the unobstructed passageway for the media to flow. When the gate of a water lug butterfly valve lowers, it closes and blocks the media flow.

  There is a non-linear relationship between the gate valve&#;s vertical travel and the flow rate, with the most significant changes occurring near the complete closure. Its relatively high velocity at partial opening causes gate and seat wear when it is used to regulate the flow. It, along with possible gate vibrations, shortens the valve&#;s service life. That is why it should only be used for on or off controls.

  As this multi-turn valve turns open or closes multiple times, its slow operation helps prevent water hammer effects. This gate valve testing standard is used for a vast number of fluids under the following working conditions:

  • Potable water, wastewater, and neutral liquids: Temperature must be between -20 and +70 °C, with a maximum of five m/s flow velocity and up to 16 bar differential pressure. 
  • Gas: Temperature should lie between -20 and +60 °C, with a maximum 20 m/s flow velocity and up to 16 bar differential pressure.

  Storage Conditions For a Gate Valve:

  Source: Deposit Photos

  A gate valve is made using a variety of materials and seat types. These devices are easy to use and long-lasting if installed and maintained correctly. However, their installation techniques vary slightly for different end connections, but the other instructions remain the same.

  Like any other industrial equipment, it is essential to store a valve under ideal storage conditions to keep it from wearing before time and spending money on gate valve repair. People wishing to make the most out of this device should keep it in a cool and well-ventilated space if stored for an extended period. But doing this much is not enough.

  To protect the seat and seals of a hydraulic lift valve, it is suggested not to unpack it until they are ready for installation. By doing this, people preserve the valve from catching dust and debris, which may eventually cause seat leakage and thus cause the device to malfunction.

  Maintenance Tips:

  Source: Deposit Photos

  To continue using a valve for a long time, it is necessary to look after its maintenance. One may achieve it by operating each valve in suitable temperature conditions. To let a valve function properly, adjust it to the ideal temperature, depending on the material type.

  • Brass: Valves made of brass must not be used under temperatures above 450 degrees F as they may damage under such conditions.
  • Iron: Valves made of iron should also not be used under temperatures greater than 450 degrees F.
  • Stainless steel or White Iron: A high pressure stainless steel ball valve is suitable for conditions with low temperatures. In contrast, a corrosive flow valve must not be used in high temperatures.
  • Stell Steel: Valves made using this material are suitable for high temperature and high-pressure working conditions.

  Some other essential maintenance tips for a gate valve include the following:

  • If the gate valve is not used regularly, cycle it at least once a month.
  • Before performing any maintenance work, relieve the system pressure.
  • Reverse the installation of a gate valve testing procedure to remove debris from the pipelines.
  • When replacing the valve, remove its top body (bonnet) and stem. Screw out the gate to replace it with the new one. Install the entire body and refit into the line.

  The Bottom Line:

  Source: Deposit Photos

  We hope this blog helps everyone learn everything about gate valve leakage, from its inspection to avoidance and fixing. Since this device is available in multiple designs and materials to offer effective sealing for different applications, it should be taken care of. If the users do not provide it with proper maintenance, it may malfunction after a certain period.
  
  If a gate valve starts leaking, the best thing to do is to replace it with a new one. Please contact us to purchase the most trustable and long-lasting gate valves in the market.

  Gate Valve Uses and Repair

  A Comprehensive Guide to Gate Valve Uses and Repair

  Figure 1: Gate valve

  A gate valve allows the media to flow through freely or stops the fluid flow completely. Gate valves are used in the power, waterworks, wastewater, pipeline, oil and gas production industries, and commercial buildings. When undertaking new installations, maintenance, or repair works, gate valves help isolate certain areas in the water supply network or reroute fluid flow to desired pipeline sections. Gate valves can sometimes get damaged. The following guide discusses case scenarios of when these valves might need repair and the steps to make repairs.

  Table of contents

  View our online selection of gate valves!

  • Gate Valves

  What is a gate valve?

  Gate valves are control valves used to shut off fluid flow completely or provide unobstructed flow within a pipeline. A gate valve consists of a valve body, gate, seat, stem, gasket, and a wheel for operating the valve, as seen in Figure 2. The gate and seat together perform the function of shutting off fluid flow. Read our article on gate valves for more information on a gate valve&#;s working principle and the various types of gate valves.

  Figure 2: Gate valve cross section: gate valve (A), handwheel (B), stem (C), gasket (D), bonnet (E), valve body (F), and flange (G).

  Gate valve issues

  Several issues can affect gate valves. Handling each problem effectively helps avoid further complications. The most common causes of gate valve failure are corrosion and general wear and tear over time. The following sections summarize some of the main challenges gate valves face and how to troubleshoot and fix them.

  Gate valve fails to close

  Troubleshooting

  A gate valve can fail to close as expected when sediment builds up inside its body. Sediment buildup occurs mainly when the gate valve operates fully open for a longer time than expected, causing dirt to build up at the sides and preventing its closure. The sediments get stuck between the gate and valve&#;s interiors when the gate lowers, causing problems.

  How to fix the problem

  1. Start by closing the gate valve as far as possible. Please note that excessive pressure should not be applied during this step.
  2. Open a sink faucet to flush debris out of the system.
  3. Open the gate valve as far as possible.
  4. Repeat the opening and closing cycle until the gate seats altogether, or the gate stops making any progress towards closing. This action usually breaks loose and flushes any built-up debris out of the valve. If the valve doesn&#;t show downward progress without shutting off the water flow, it needs to be taken out for evaluation. Switch to Step 5 if this happens.
  5. Shut off the water supply and remove the gate valve.
  6. Use a wrench to remove the valve housing from the top. Ensure not to loosen the packing nut that holds the packing and prevents water from leaking around the handle.
  7. Evaluate the outer edges of the gate and scrape off any deposits before reassembling the valve.
  8. Slide the gate back into its guide and tighten the top of the valve housing using a wrench.
  9. Turn on the water supply and test the valve again.
  10. Replace the valve if it is severely corroded or filled with debris.

  Gate valve stuck

  Another common challenge with gate valves is that they can get stuck. The gate valve can be seized open or closed, due to which it cannot perform its function correctly.

  Troubleshooting a stuck gate valve

  Perform the following steps before checking a stuck gate valve:

  1. Stop the water flow to understand the problem better.
  2. Isolate your working area to avoid the adverse effects of further leaks.
  3. Examine the area to understand whether there are external factors that cause the problem, like excess cold or a damaged water line. Wear and corrosion can also prevent gate valves from opening.
  4. Place a container under the damaged valve to drain the excess water (in case the gate valve is seized open) before removing or fixing it.

  How to fix a stuck gate valve

  1. Clean any atmospheric deposits from the gate valve threads.
  2. Apply 3-in-one or penetrating oil to the gate valve. Wipe the excess oil with a rag and ensure that the oil reaches the valve's threads.
  3. Tap the valve handle with a hammer to check if the valve changes position from open to closed.
  4. Attach an adjustable wrench or channel lock on the valve handle. It is advisable to wear gloves while working to avoid slipping and ensure a stable working surface.
  5. Warm the handle using a hair drier or blow torch.
  6. Turn the valve handle to check if it changes the valve position.

  Gate valve leaking from stem

  Old and new valves can leak around the stem section, mainly when the valve handle is turned to open or close the valve. Several reasons can cause this leakage: not often fully closing the valve, damage to the valve, poor design, and using the wrong size gate valve.

  Troubleshooting

  1. Tightening: Turn the gate valve handle to check if the leakage is caused by the valve failing to close. Gate valves fail to close fully when sediment builds up inside the valve's body.
  2. Damaged valve stem: Check whether the valve&#;s stem area has been damaged. Wear and corrosion are the most common causes of such damage.
  3. Check the design and valve size: Ensure that the valve stem is compatible and designed for your specific valve. If not, replace the valve stem.

  How to fix the problem

  1. Tighten the packing nut. The packing nut makes a strong watertight seal where the valve stem meets the water line. So, if there is a leak at the valve stem, it likely means the valve is not completely stopping the flow. Hence, the first step you should do to stop the leak is to tighten the packing nut.
  2. Replace the valve stem packing material or washer. When the gate valve&#;s packing nut is tightened, it confines the packing material against the washer to prevent any water from passing through. This packing material hardens over time, forming a solid seal that causes the valve to leak. In this case, it is better to replace the stem packing material, which can be found at most hardware stores.

  How to take apart a gate valve for repair

  Perform the following steps to take apart a gate valve for repair:

  1. Turn off the main water supply.
  2. Detach the valve from the pipes by unbolting the flanged ends.
  3. Loosen the valve bonnet using pliers. Do not loosen the packing nut because this part ensures that there are no leaks in the stem.
  4. Remove the valve's top to separate the seating and handle from the body.

  You can now examine each part for possible faults. Use a cleaning tool such as a toothbrush to clean each valve part. If there are any faults, replace the affected parts; else, start the rebuilding process. When rebuilding, place the gate in the appropriate position in the valve's body, then screw the bonnet until it is secure. Now turn the handle to see if the valve is working. The gate should be able to open and close fully. If all is well, place the valve back on the pipeline.

  Note: It is advisable to use industrial valve sealant tape to put the valve back in the pipeline.

  Replacing a gate valve with a ball valve

  Always go for ball valves rather than gate valves whenever possible. Ball valves are generally more effective, although they are more expensive. Ball valves form a tighter seal when closed, and they are more reliable and durable than gate valves. Perform the following steps to replace a gate valve with a ball valve:

  1. Heating up: Before replacing the gate valve, get a torch to heat the parts (valve joints and handle stem) for removal.
  2. Turn off the water: Drain the water from the pipes by turning it off. Then, open the gate valve and heat the valve joints.
  3. Use channel locks: Grab the valve with a hammer to see whether it moves. If it does, it is hot enough. If it does not move, apply heat on adjacent elbows and some lateral pressure.
  4. Final installation: Now install the ball valve.

  Read our gate valve vs ball valve article for a thorough comparison between both valve types.

  FAQs

  Are ball valves better than gate valves?

  Yes, ball valves have less response time and better sealing properties than gate valves.

  Which tools should I keep in my gate valve repair kits?

  Get a seat removal tool, a screwdriver, and a wrench set.

  Can gate valves fail?

  Yes, gate valves can fail due to wear and corrosion and must be troubleshot for possible faults.

  Why is my gate valve leaking?

  The gate valve can leak due to the lack of complete closure, damage, poor design, or the use of the wrong size with its application.

  View our online selection of gate valves!

  • Gate Valves