Bellow Seal Globe Valve: Uses and Working Principle

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Industrial valves are simple devices that are multi-functional and developed to manage the flow of fluid by regulating the passageway or pipes. Commonly used in the domestic plumbing system, faucets, and commercial buildings, valves have the basic function to let the water come out and turning it back to water stops flowing. When it comes to the types of ball valves that exist in the market, there are certain categories such as ball valve, gate, pinch, butterfly, diaphragm, and globe valves. In comparison to the other types, globe valves offer greater precision for the purpose of regulating flow. Bellow Seal Globe Valve, being spherical in shape, is named so and is preferably used in applications where fluid flow needs to be finely tuned.

Just like the gate valves, the globe valve follows a linear pathway to throttle flow. However, both types vary in terms of using a disk in the place of a wedge. The merit of using globe valves over others is that they can be easily adjusted to higher or lower flow and it does not leak as the other types of valves. Due to their specific design and structure, these valves are known to provide excellent control to normalize the fluid flow. Usually, water pipes are fitted with these kinds of valves. So that the operator can control the regulation inside the pipe by opening the valve partly or completely opening it. This is the reason the globe valve is believed to be the most popular valve to be used for different applications.

Sealability as a Vital parameter for a Globe valve:

One of the most basic and crucial features of all kinds of valves is sealability, which can be detached into the external and internal seal. The exterior sealing reveals the sealing between the moving parts of the valve stem and bonnet, body, and connection, and also to the valve body and bonnet. On the contrary, the internal seal indicates the connection between the seat and the valve clack.

The inadequate sealability and lack of strength may damage the parts of the valve. It may lead to monetary loss at different levels, including in transportation, explosive and corrosive fluid. Or it might lead to a serious accident as well. What ensures the sealing of the valve is following the standards to design that should be according to the material of the product.

Defining Bellow seal globe valve?

There is no such big difference between a control valve and a bellow seal valve structural design. What distinguishes the later one is the use of bellows to seal the components of the valve stem. There are several characteristics of bellow values that are helpful in passing even the hazardous and explosive media.

The typical utilization of the bellow seal valve is like the obstruction between air and fluids. At the same time, the unit ensures fluid leakage with zero leakage of pipelines.

Now, what can be done to avoid processing fluids affecting the valve stem? The bellows of the bottom are welded to the stem while the flip side of the bellows creates a static seal between the bonnet and the body of the valve.

Different industries today are in great need of Bellow Seal Globe Valves for their applications. Such industries include modern nuclear, petrochemical, automation control, electric and space, long-distance fluid transportation, and others. To ensure good sealability and desired strength, valve manufacturers are focusing on expanding other parameters of the valve so as to develop automatic, energy-saving, and multi-functional valves.

Bellow materials

In usual conditions, the bellow seal globe valve is made up of cast iron or cast copper. It proves beneficial for low-pressure and non-corrosive fluid. Whereas, for the high or medium pressure fluid, the valve is made up of cast steel or forged steel.

Using alloy steel is preferred for high-temperature or high-pressure fluids. In addition to these materials, plastics, stainless steel, lead alloy, and titanium alloy are preferred materials for regulating corrosive fluid. In particular, such valves ensure high and efficient functionality in the above-level temperature and pressure applications.

When it comes to distinguishing materials, the ones that have gained huge attention in the industry are stainless steel with Titanium to survive high pressures and temperatures. Inconel 600 or 625 enhances fatigue strength and makes it resistant-free as opposed to the stainless steel bellows.

What’s more, Hastelloy C-276 ensures works better in terms of avoiding corrosion and fatigue. The only solution here is to make use of different bellow systems for the purpose to minimize the stroke length and improving the utility life.

In order to perfectly manage above-level pressure fluids, the beneficial thing is to use a multi-ply design. Such utilization leads to a two-ply bellow which can directly impact the pressure rating in contrast to using a single ply bellow with a similar thickness level. The reason is clear; there are more benefits of utilizing multi-systems over a single-ply system.

Metal fatigue is common bellow that can induce weld failure.  Now there are some usual aspects that impact the fatigue life and such include the technique to fabricate, length of the stroke, frequency of the stroke, fatigue life, and others.

Types of bellow

Typically, there are two kinds of the bellow. The one that is more commonly used in industrial applications is the Forged Bellow while another less common is the Welded. Their construction is simple, just by converting a flat sheet into a tube that is fusion welded. The tube formation in this regard is turned into bellow that is circular in shape and possesses folds. In moving toward understanding the welded type, it is significant to know that their creation is done by welding process with thin plates and the specified inner/outer circumference of the plates.

Common features of Bellow Seal Globe Valves:

Reduced gland leakage

From the gland parts, the adequate utilization of bellows minimizes the leakage risk.

Ideal for energy savings

The loss of energy no to little leakage is controlled. This aspect leads to protecting the environment.

Prevents minor leakage

The use of bellows guarantees leakage, which makes them ideal to prevent minor leakage from gland components. In addition, bellow seal globe valves suit safety aspects for toxic liquids, flammable liquids, and also for liquids with odors.

Easy to maintain

Reduces maintenance expense as the bellow seal globe valves do not require to be regularly retorqued.

Ensures liquid quality

Both the stem and the gland components are sealed with bellows to avoid contact with liquids in pipes.

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Durability

The bellow seal globe valve ensures good durability as these are built from a single metal. The most attractive characteristic is the reliability that is enough good for forged types. While it is low for welded ones because of the small-sized spots that affect their life cycle.

Quality control

For the forged ones specifically, it is easy to test quality as they are formed uniformly. However, in the welded bellows, it becomes difficult to inspect the welded spots for quality purposes.

The basic structure of bellow seal globe valve

The structure is simple and standard that has a rotation-less stem and handles to avoid bellows twisting.

The structure further has gland packing that helps prevent external leakage. Its structural design for the bolt is convenient to maintain and manage with the bolt being tightened and that ensures quick and safe fastening. The hydraulic multi-layer bellows are used that feature excellent features and corrosion resistance.

For the upper gasket, the expanded graphite seat is used to restrict the external leakage in the event of bellows breakage.

Regular Globe valves vs Bellow seal globe valves

Now what distinguishes the bellow seal globe valves from the standard globe valve is the sealing performance. This aspect makes the bellow ones more efficient to provide the security of pipelines.

This is the regular type which is seal packed and works best to avoid forming tight contact with the stem of the valve. This usually causes high leakage specifically under low temperatures.

When it comes to usage, the difference is huge again. Generally, the bellow ones are used for pipelines with permeable media like ammonia. However, the regular ones are used for standard purposes where sealing performance is not a big concern.

These are spherical in design and provide greater accuracy than different sorts of valves when it comes to regulating flow. As per the Globe Valve Manufacturer, these types are mainly used for purposes the place liquid desires to be finely tuned. Due to their precise format and structure, these valves are acknowledged to furnish extraordinary manipulation to normalize the fluid flow. Usually, water pipes are outfitted with these types of valves so that the operator can manipulate the interior of the pipe with the aid of opening the valve partly or definitely opening it. The functioning here makes it efficient for the industries to avoid volatile leaks.

In addition, the industries cannot expect any loss in media due to the usage, however in the regular kinds; they may have to face such circumstances. The only reason for good bellow valve life in comparison to the others.

Working principle for Bellow Seal Globe Valve

During the installation times, different positions can be made in possible ways. Following this way will save the debris accumulation in the bellow. While the process is under, it is required to ensure that the pipes installed do not contain any kind of impurity. Such a connection can be created so as to circumvent tension that acts on the valve.

Not like the other kinds of valves, a unique methodology is followed in the below case.  Here, a metal tube connected to the bonnet and valve stem is used to create a leak-proof seal with no friction or resistance.

The utilization of the accordion ribs makes the bellows stretch and compress with a stem’s linear motion. Being the uninterrupted metal tube, bellows leave no chance for leakage.

The port on the extended bonnet serves as the connection point to inspect fluid leakage. Also, in some applications, the On and Off system is used to take immediate action on detection.

The detection sensor used in the system can be as modest as can be calibrated at some pressure level. On breaking the bellow seal breakage, the detector sensor may indicate the leak with the packing to ensure quality working until repairing work gets completed.

What Is a Bellows Seal Globe Valve?

A bellows seal globe valve is a specially designed valve that is highly suitable for industries dealing with hazardous substances. The valve’s unique design ensures that even the smallest leakages, which can be extremely critical in certain industries, are prevented. This is particularly important in industries such as the chemical and nuclear industry, where there is a high risk of leakage, explosion, and health hazards due to the flow of flammable, hazardous, extremely poisonous, and toxic media through the pipelines. The bellows seal globe valve, therefore, meets specific stringent leakage and sealing requirements that are essential in such industries.

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How Do Bellows Seal Globe Valves Work?

Bellows seal globe valves work by using a compact structure that includes bellows for sealing the valve stem components. The bellows valve has a bellow inside, and the lower end of the stainless-steel bellows is welded to the stem to prevent the system fluid from eroding the stem. The other end is positioned between the body of the valve and the cover of the valve to create a permanent seal. This double seal configuration eliminates leakage. Even if the bellows collapse, the stem packaging will prevent further leakage. The bellows are welded to the valve stem to ensure stable operating efficiency and prevent the vibration of the valve stem induced by the movement of the valve insert.

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What Are the Key Components of Bellows Seal Globe Valve?

The key components of a bellows seal globe valve include the metal bellows, bonnet, the lower end and stem assembly, the upper end and connecting plate, and the sealing surface of the valve disc.
The metal bellows are the main feature of a bellows seal globe valve. They are made by rolling a flat sheet into a tube and then mechanically forming it into a bellow with rounded and widely spaced folds. Inconel is a common material used for making bellows due to its high resistance to corrosion and high temperatures. Cryogenic valves are also commonly made with metal bellows for their ability to withstand extreme temperatures.

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The lower end and the stem assembly are welded together, while the upper end is welded on the connecting plate using socket weld. This creates a metal shield between the fluid medium and the environment, ensuring zero leakage from the valve stem. The stem seals are an important component of the bellows seal globe valve, ensuring a tight seal and preventing leaks.
The sealing surface of the valve disc and the valve structure is precisely ground to confirm that it has passed a pressure rating test and that any possibility of leakage is eliminated. Graphite packing is used to ensure a tight seal and prevent any leaks from occurring.

What Industries Primarily Use Bellows Seal Globe Valves?

Bellows seal globe valves are a crucial component in a wide array of industries due to their exceptional sealing capabilities and robust design. The primary industries that utilize these valves are those where the prevention of leakage is of utmost importance, particularly when dealing with hazardous or toxic substances. These valves can be integrated with an API (Application Programming Interface) to provide real-time monitoring and control, making them an even more valuable asset in industries where safety and efficiency are top priorities.Petrochemical Industry: One of the key sectors that heavily rely on bellows seal globe valves is the petrochemical industry. These valves are used in various processes where they control the flow of flammable and potentially harmful substances. Their superior sealing performance ensures that there are no leakages that could lead to accidents or environmental contamination.Nuclear Industry: The nuclear industry is another sector where bellows seal globe valves, classified as ASME Class, are extensively used. In nuclear power plants, these valves play a crucial role in controlling the flow of radioactive substances. The double sealing design of these valves ensures that there is no leakage of radioactive material, thereby ensuring the safety of the plant and its surroundings.

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Chemical Industry: Bellows seal globe valves are also widely used in the chemical industry. They are used to control the flow of various chemicals in the production processes. The valves’ ability to withstand corrosive substances and high temperatures makes them an ideal choice for this industry.Electronics Industry: Other industries that use bellows seal globe valves include the electronics industry, where they are used in the production of semiconductors and other electronic components. They are also used in various plants such as power plants, water treatment plants, and manufacturing plants where they control the flow of gases and liquids. The vacuum industry also uses these valves due to their ability to maintain a high level of sealing under low-pressure conditions.

What Are the Advantages of Bellows Seal Globe Valve?

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1. Exceptional Sealing Performance: The double seal design comprising the bellows and stem packing ensures superior sealing performance. Even if the bellows were to fail, the stem packing would prevent any leakage, meeting international sealing standards. This high level of sealing capability is critical, especially in industries dealing with hazardous or toxic substances, where even the smallest leakages can have severe consequences.
2. Safety and Environmental Protection: Bellows seal globe valves minimize the loss of medium fluid, enhancing the safety of the plant where they are installed. This feature is particularly crucial in industries handling hazardous materials that could lead to accidents, health risks, or environmental pollution if leaked.
3. Energy Conservation: By reducing energy losses due to leakage, bellows seal globe valves contribute to energy conservation. This not only helps save costs but also aligns with environmental sustainability goals by reducing overall energy consumption.
4. Durability and Cost Savings: With minimized leakage, bellows seal globe valves require less frequent maintenance and replacements. The extended valve life results in significant cost savings in terms of maintenance and replacement expenses.
5. Maintenance-Free Operation: The rugged bellows seal design ensures zero leakage from the valve stem, providing maintenance-free conditions. This improves operational efficiency and reduces downtime for maintenance activities.

What Are Some Types of Bellows Seal Globe Valve?

Bellows seal globe valves come in various types, each designed to meet specific application requirements. Here are some common types:

1. Welded Ends Bellow Seal Globe Valve: This type of valve is characterized by its welded ends, providing a robust and leak-proof connection. It’s ideal for high-pressure applications where a strong connection is essential.
2. Flanged Bellow Seal Globe Valve: This valve features flanged ends, which allow for easy installation and removal. It’s suitable for applications that require regular maintenance or replacement of the valve.
3. Socket-Welded Bellows Seal Globe Valve: This type of valve has socket-welded ends, providing a strong, leak-proof connection. It’s ideal for high-pressure applications and is often used in the petrochemical and nuclear industries.
4. Threaded Bellows Seal Globe Valve: This valve features threaded ends, making it easy to install and remove. It’s suitable for low to medium pressure applications.
5. Extended Bellows Seal Globe Valve: This valve features an extended bellows seal, providing additional protection against leakage. It’s ideal for applications that require a high level of sealing performance.
6. Y Pattern Bellows Seal Globe Valve: This valve features a Y pattern body, which allows for a more streamlined flow of fluid through the valve. It’s ideal for applications that require a high flow rate.

How to Select the Bellows?

1. Inner Diameter: The inner diameter of the bellows should be greater than the stem diameter, typically 115 mm. This allows the stem to move freely within the bellows without causing any damage.
2. Outer Diameter: The outer diameter of the bellows is usually selected based on the inner diameter. The ratio of the outer to the inner diameter is generally between 113 to 115.
3. Wall Thickness, Number of Layers, Corrugations, and Length: These specifications should meet the requirements of pressure resistance, stroke, and cycle life of the corrugated pipe, ensuring that the bellows can endure operational pressures and temperatures.
4. Bellows Design: For handling higher pressures, a multiply design of bellows (using 2 or 3 piles of the metal wall) is recommended.

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5. Material: The material of the bellows components should be selected based on the allowable temperature range, formability, welding performance, and compatibility with the medium. This guarantees the longevity of the bellows in various operational conditions.

What Is the Difference Between a Bellows Seal Globe Valve and a Normal Valve?

AspectBellows Seal Globe ValveNormal ValveSealing MechanismDouble seal (bellows + packing)Single sealLeakage PreventionExceptional sealing performanceLess reliable sealingApplicationHazardous or toxic substancesGeneral applicationsSafetyHigh safety standardsStandard safety precautionsEnvironmental ProtectionMinimizes medium fluid lossMay cause fluid leakageEnergy ConservationContributes to energy savingsEnergy losses may occurDurabilityLonger valve lifeStandard valve lifespanMaintenanceReduced maintenance needsRegular maintenance requiredSuitable for High-PressureYesYes (depending on the type)Suitable for High-TemperatureYesYes (depending on the type)Material CompatibilityResistant to corrosive fluidsMay be prone to corrosionCostHigher initial costStandard cost

What Causes Leakage in Bellows Seal Globe Valves and How Can It Be Prevented?

Causes of LeakagePrevention MeasuresDamage to the BellowsRegular inspection and immediate replacement of damaged bellowsExcessive PressureUse of pressure relief devices and adherence to operating limitsCorrosive SubstancesUse of corrosion-resistant materialsHigh TemperatureUse of temperature-resistant materials and cooling mechanismsImproper InstallationProper installation following manufacturer’s instructionsPoor MaintenanceRegular and thorough maintenance routinesLow-Quality MaterialsUse of high-quality, durable materialsPoor Manufacturing ProcessesSelection of valves from reputable and reliable manufacturersIncorrect OperationTraining and adherence to correct operating procedures

What Are Some Precautions Should Be Taken While Using Bellows Seal Globe Valves?

1. Adhere to Manufacturer’s Instructions: Always read and follow all instructions and warnings provided by the manufacturer to prevent valve damage and potential safety hazards.
2. Proper Installation: Ensure the valve is installed correctly to prevent leakage and other operational issues. Incorrect installation can lead to numerous issues, including leakage and inefficient operation.
3. Suitability for Application: Check the pressure and temperature ratings and ensure the valve material is compatible with the fluid being handled. The valve should suit the specific requirements of your application.
4. Regular Maintenance and Inspection: Regularly inspect the valve for signs of damage or wear and replace any damaged components promptly. If the bellows are damaged, immediate replacement is necessary to prevent leakage.
5. Use As Intended: The valve should always be used in accordance with its intended purpose. Using the valve in applications for which it is not designed can lead to damage and potential safety hazards.

Conclusion

In conclusion, bellows seal globe valves are an essential component in many industries due to their superior sealing capabilities and robust design. They offer numerous advantages, including enhanced safety, environmental protection, and energy conservation. However, it’s important to select the right bellows and take necessary precautions to ensure safe and efficient operation.

Opt for Dombor

When it comes to bellows seal globe valves, Dombor is a trusted name in the industry. With a commitment to quality and innovation, Dombor offers a wide range of bellows seal globe valves designed to meet the specific needs of various industries. Whether you need a welded ends bellow seal globe valve for high-pressure applications or a flanged bellow seal globe valve for easy installation and maintenance, Dombor has you covered. With Dombor, you can be assured of superior performance, durability, and reliability. Choose Dombor for all your bellows seal globe valve needs.

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