How to Choose bellow seal globe valve?

06, May. 2024

 

Bellows Seal Valve - Conval, Inc.

Bellows seal valves are valves employed in piping systems to safeguard against leakage. When selected and installed properly, they minimize the risk of potentially harmful chemicals causing injury or illness to workers and damage to the surrounding environment.

If you want to learn more, please visit our website Afbv Valve.

Standard Bellows Seal Sizes

Sizes through 4”

Pressure Rating

Through ASME Class through 2500 #

Standard Forging ASME Materials

SA 105, SA 182-F22, SA 182-F91, SA 182-F92, SA 182-F316
Other materials available upon request.

Accessories

Actuators – Electric, Pneumatic or Hydraulic
Locking Devices – Open, Closed or Both
Limit Switches – Single or Dual
Stem Shroud
Position Indicator
Leak-Off Port

Bellows Seal Design Features

Conval Bellows Seal Valve vs. Packed Valves

Packed valves require two seal boundaries: a 360° seal on the stem surface and a 360° seal on the stuffing box wall. The Conval bellows seal valve removes these two leak paths. Conval bellows seal valves are used when packed valves may not reliably contain light gases or hazardous system fluids. In all applications, the 6-ply Inconel®, welded bellows stem seal is more reliable than sliding stem seals.

Zero Fugitive Emissions

Every Conval bellows assembly is tested for zero leakage using a helium gas mass spectrometer before undergoing further shell and seat leakage testing. Conval’s bellows seal emits no detectable leakage, well beyond Method 21 Fugitive Emissions Test Protocol.

No Torsion of the Bellows

A robust rising, non-rotating stem system prevents destructive torsion, providing extremely long service life from the advanced bellows design.

Three Body Styles

Conval bellows seal valves are available in Y-pattern, Angle-pattern, and T-pattern body styles.

Low Operating Torque

The manual bellows seal valve is provided with a rugged bearing system and grease fitting to minimize operating torque over the life of the valve.

Double Back-up Seating

In the full open position, Conval bellows seal valves are equipped with a superior backseat, isolating a secondary stem seal from the process fluid. The graphitic stem seal is precisely loaded by Conval’s balanced axial gland and Integral Gland Wrench (IGW), providing superb sealing to back up the bellows.

Extended Seat Life

Positive shut-off is achieved over a very long operational life due to the solid cobalt-chrome seats and discs, even in high cycle and high fluid velocity services. A cobalt-free option is available for nuclear and chemical applications.

Flexibility of Design

Conval offers a double height bellows which provides the highest bellows valve flow capacity (Cv) available per pipe size. Test ports (with lantern gland) may also be specified.

Axially-loaded Packing System

The Axial design ensures tight concentricity, which eliminates side loading of the packing and minimizes wear forces on the trim components. This feature is critical for superior valve performance.

Pressure Seal Bonnet

The simple and effective pressure seal bonnet provides ready access for servicing with no welds to cut or seal rings or gaskets to replace. The body-to-bonnet joint integrity is maintained through countless thermal cycles.

Single-piece Gland

In extreme environments, the simpler the design and the fewer the parts, the better. The durable single-piece stainless steel gland contributes to the longevity of the valve.

Pressure-Actuated Backseat

The Clampseal® pressure-actuated backseat provides maximum valve integrity by ensuring a positive internal stop for the valve stem and disc assembly. The pressure actuated backseat also extends packing life by securely isolating the packing from the pressure when the valve is fully open.

Rapid In-Line Renewability

The CLAMPSEAL® Valve is much easier to renew than anything else on the market. The CLAMPSEAL® Valve line provides a modular solution to rising maintenance expenses. Low acquisition cost is not as important as low cost over the serviceable life of a valve. Maintaining a Conval valve is far easier and much less costly than replacing a competitor’s valve.

Bellows Seal Valve - Conval, Inc.

Bellows seal valves are valves employed in piping systems to safeguard against leakage. When selected and installed properly, they minimize the risk of potentially harmful chemicals causing injury or illness to workers and damage to the surrounding environment.

Standard Bellows Seal Sizes

Sizes through 4”

Pressure Rating

Through ASME Class through 2500 #

Standard Forging ASME Materials

SA 105, SA 182-F22, SA 182-F91, SA 182-F92, SA 182-F316
Other materials available upon request.

Accessories

Actuators – Electric, Pneumatic or Hydraulic
Locking Devices – Open, Closed or Both
Limit Switches – Single or Dual
Stem Shroud
Position Indicator
Leak-Off Port

Bellows Seal Design Features

Conval Bellows Seal Valve vs. Packed Valves

Packed valves require two seal boundaries: a 360° seal on the stem surface and a 360° seal on the stuffing box wall. The Conval bellows seal valve removes these two leak paths. Conval bellows seal valves are used when packed valves may not reliably contain light gases or hazardous system fluids. In all applications, the 6-ply Inconel®, welded bellows stem seal is more reliable than sliding stem seals.

Zero Fugitive Emissions

Every Conval bellows assembly is tested for zero leakage using a helium gas mass spectrometer before undergoing further shell and seat leakage testing. Conval’s bellows seal emits no detectable leakage, well beyond Method 21 Fugitive Emissions Test Protocol.

No Torsion of the Bellows

A robust rising, non-rotating stem system prevents destructive torsion, providing extremely long service life from the advanced bellows design.

Three Body Styles

Conval bellows seal valves are available in Y-pattern, Angle-pattern, and T-pattern body styles.

Low Operating Torque

The manual bellows seal valve is provided with a rugged bearing system and grease fitting to minimize operating torque over the life of the valve.

Double Back-up Seating

In the full open position, Conval bellows seal valves are equipped with a superior backseat, isolating a secondary stem seal from the process fluid. The graphitic stem seal is precisely loaded by Conval’s balanced axial gland and Integral Gland Wrench (IGW), providing superb sealing to back up the bellows.

Extended Seat Life

Positive shut-off is achieved over a very long operational life due to the solid cobalt-chrome seats and discs, even in high cycle and high fluid velocity services. A cobalt-free option is available for nuclear and chemical applications.

Flexibility of Design

Conval offers a double height bellows which provides the highest bellows valve flow capacity (Cv) available per pipe size. Test ports (with lantern gland) may also be specified.

Axially-loaded Packing System

The Axial design ensures tight concentricity, which eliminates side loading of the packing and minimizes wear forces on the trim components. This feature is critical for superior valve performance.

Pressure Seal Bonnet

The simple and effective pressure seal bonnet provides ready access for servicing with no welds to cut or seal rings or gaskets to replace. The body-to-bonnet joint integrity is maintained through countless thermal cycles.

Single-piece Gland

In extreme environments, the simpler the design and the fewer the parts, the better. The durable single-piece stainless steel gland contributes to the longevity of the valve.

Pressure-Actuated Backseat

The Clampseal® pressure-actuated backseat provides maximum valve integrity by ensuring a positive internal stop for the valve stem and disc assembly. The pressure actuated backseat also extends packing life by securely isolating the packing from the pressure when the valve is fully open.

Rapid In-Line Renewability

The CLAMPSEAL® Valve is much easier to renew than anything else on the market. The CLAMPSEAL® Valve line provides a modular solution to rising maintenance expenses. Low acquisition cost is not as important as low cost over the serviceable life of a valve. Maintaining a Conval valve is far easier and much less costly than replacing a competitor’s valve.

How Do Bellows Seal Valves Work?

These valves feature an accordion like bellows—i.e., the bellows cartridge component, welded to the valve stem and bonnet. During the valve stroke the bellows compress or expand along with the sliding stem’s linear motion with little to no friction.

Types of Bellows

  • Formed bellows: Conval’s standard design, formed bellows begin as flat sheet (thin wall foil) rolled into a tube and fusion-welded longitudinally forming a single layer.  Thin metal layers are combined to form multi-ply bellows.  Mechanical or hydrostatic force forms the bellows with wide-spaced rounded folds. Conval has supplied bellows with as many as 6 plies for higher pressure applications.
  • Welded bellows: Welded bellows are manufactured by welding washer-like plates of thin metal at both their inner and outer circumferences.

Types of Bellows Seal Valves

Gate valves, globe valves and ball valves may all be supplied with Bellows should the application require.

Applications of Bellows Seal Valves

These critical components are an essential part of safe fluid system operation in a broad range of industries, including the following:

  • Aerospace
  • Biotechnology
  • Chemical processing
  • Fossil power
  • Nuclear power
  • Petroleum
  • Pharmaceutical
  • Semiconductor manufacturing
  • Vacuum and ultra-high vacuum

FAQs

Below we provide answers to some of the most frequently asked questions (FAQs) regarding bellows seal valves.

What are some advantages of using bellows seal valves?

The primary function of bellows seal valves is preventing potentially harmful or toxic fugitive emissions which can negatively affect unprotected humans and the surrounding environment. In addition to reducing the risk to employees or the environment, these valves decrease the amount of material lost during operations, which translates to lower overall material costs and greater throughput.

How do I choose a bellows seal valve?

When selecting a bellows seal valve for a system, there are several factors to keep in mind. Some of the key design considerations are:

  • The valve material chosen should be compatible with the operating conditions of the system, including the fluid media, temperature, and pressure. Common materials employed include stainless steel and nickel-based super alloys.
  • Pressure rating. The valve should be rated to handle the range of pressures and temperatures expected from the fluid system. Typical ratings range from ASME 150 to 2500 class.
  • Design Qualifications. Ensure the bellows is qualified to industry standards such as EPRI, MSS, API, or ISO.
  • The size of the valve should suit the design of the system. Conval bellows seal valves are available in sizes ranging from ¼ inch through 4 inch NPS.

How to prevent bellows seal valves from failing

Bellows seal valves are built for reliable operation. While rare, failures do occur. Generally, the root cause of the failure stems, not from the quality of the valve or bellows, but from improper selection, installation, or operation. Some guidelines for avoiding valve failure include:

  • Monitor for excessive back pressure or high inlet pressure variations
  • Select properly sized valves and bellows
  • Operate within the design pressure, temperature and stem stroke ranges.
  • Prevention of cavitation, flashing and other unusual damaging flow conditions.

Contact the Valve Experts at Conval, Inc. Today

For all your bellows seal valve needs, turn to the valve experts at Conval, Inc. Since our founding in 1967, we have developed a reputation as a premier manufacturer of high-pressure/temperature, forged steel valves suitable for use in the most demanding severe service applications. Our commitment to quality translates to our products’ superior durability and performance at the lowest life-cycle cost in the industry.

For additional information about our valve offerings or assistance specifying one (or hopefully many) for your application, contact us today.

The Comprehensive Guide to Bellow Seal Globe Valves

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.

The Comprehensive Guide to Bellow Seal Globe Valves 1

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.

The Comprehensive Guide to Bellow Seal Globe Valves 2

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.

The Comprehensive Guide to Bellow Seal Globe Valves 3

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.

The Comprehensive Guide to Bellow Seal Globe Valves 4

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?

The Comprehensive Guide to Bellow Seal Globe Valves 5
  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.
The Comprehensive Guide to Bellow Seal Globe Valves 6
  1. 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 valvebellow 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.

How Do Bellows Seal Valves Work?

These valves feature an accordion like bellows—i.e., the bellows cartridge component, welded to the valve stem and bonnet. During the valve stroke the bellows compress or expand along with the sliding stem’s linear motion with little to no friction.

Types of Bellows

  • Formed bellows: Conval’s standard design, formed bellows begin as flat sheet (thin wall foil) rolled into a tube and fusion-welded longitudinally forming a single layer.  Thin metal layers are combined to form multi-ply bellows.  Mechanical or hydrostatic force forms the bellows with wide-spaced rounded folds. Conval has supplied bellows with as many as 6 plies for higher pressure applications.
  • Welded bellows: Welded bellows are manufactured by welding washer-like plates of thin metal at both their inner and outer circumferences.

Types of Bellows Seal Valves

Gate valves, globe valves and ball valves may all be supplied with Bellows should the application require.

Applications of Bellows Seal Valves

These critical components are an essential part of safe fluid system operation in a broad range of industries, including the following:

  • Aerospace
  • Biotechnology
  • Chemical processing
  • Fossil power
  • Nuclear power
  • Petroleum
  • Pharmaceutical
  • Semiconductor manufacturing
  • Vacuum and ultra-high vacuum

FAQs

Below we provide answers to some of the most frequently asked questions (FAQs) regarding bellows seal valves.

What are some advantages of using bellows seal valves?

The primary function of bellows seal valves is preventing potentially harmful or toxic fugitive emissions which can negatively affect unprotected humans and the surrounding environment. In addition to reducing the risk to employees or the environment, these valves decrease the amount of material lost during operations, which translates to lower overall material costs and greater throughput.

How do I choose a bellows seal valve?

When selecting a bellows seal valve for a system, there are several factors to keep in mind. Some of the key design considerations are:

  • The valve material chosen should be compatible with the operating conditions of the system, including the fluid media, temperature, and pressure. Common materials employed include stainless steel and nickel-based super alloys.
  • Pressure rating. The valve should be rated to handle the range of pressures and temperatures expected from the fluid system. Typical ratings range from ASME 150 to 2500 class.
  • Design Qualifications. Ensure the bellows is qualified to industry standards such as EPRI, MSS, API, or ISO.
  • The size of the valve should suit the design of the system. Conval bellows seal valves are available in sizes ranging from ¼ inch through 4 inch NPS.

How to prevent bellows seal valves from failing

Bellows seal valves are built for reliable operation. While rare, failures do occur. Generally, the root cause of the failure stems, not from the quality of the valve or bellows, but from improper selection, installation, or operation. Some guidelines for avoiding valve failure include:

  • Monitor for excessive back pressure or high inlet pressure variations
  • Select properly sized valves and bellows
  • Operate within the design pressure, temperature and stem stroke ranges.
  • Prevention of cavitation, flashing and other unusual damaging flow conditions.

Contact the Valve Experts at Conval, Inc. Today

For all your bellows seal valve needs, turn to the valve experts at Conval, Inc. Since our founding in 1967, we have developed a reputation as a premier manufacturer of high-pressure/temperature, forged steel valves suitable for use in the most demanding severe service applications. Our commitment to quality translates to our products’ superior durability and performance at the lowest life-cycle cost in the industry.

For additional information about our valve offerings or assistance specifying one (or hopefully many) for your application, contact us today.

The Comprehensive Guide to Bellow Seal Globe Valves

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.

The Comprehensive Guide to Bellow Seal Globe Valves 1

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.

The Comprehensive Guide to Bellow Seal Globe Valves 2

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.

The Comprehensive Guide to Bellow Seal Globe Valves 3

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.

The Comprehensive Guide to Bellow Seal Globe Valves 4

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?

The Comprehensive Guide to Bellow Seal Globe Valves 5
  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.
The Comprehensive Guide to Bellow Seal Globe Valves 6
  1. 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.

For more ANSI Bellows Seal Gate Valveinformation, please contact us. We will provide professional answers.