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Factors Affecting Sealing Performance of Concentric Soft Seal Butterfly Valves

Key Factors

  • Seat Material Selection: EPDM for seawater, NBR for oil, VITON for high temperature.
  • Machining Precision: Concentricity between valve body, disc, and seat.
  • Installation Position: Horizontal installation is preferred over vertical to avoid self-weight affecting sealing.
  • Torque Control: Excessive or insufficient torque may damage the seat.

Key Technical Points

  • Ensure concentricityamong body, disc, and seat.
  • Select suitable sealing materials.
  • Prevent high-temperature aging of the seat.
  • Apply anti-corrosion coatingsor linings to enhance seawater corrosion resistance.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.

We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Comparison Between Concentric and Double Offset Marine Butterfly Valves

Item Concentric Butterfly Valve Double Offset Butterfly Valve
Structure Disc center aligned with body centerline Disc center offset from body centerline
Sealing Type Mainly soft seal Soft+hard seal available
Operation Torque Low Slightly higher
ApplicationPressure Low to medium pressure(PN6-PN16) High pressure(PN25-PN40)
Cost Lower Higher
Typical Application General ship pipelines,ballast water systems High-ressure fire system,deck wash system

 

 

triple eccentric butterfly valve-wafer-butt weld (1)

Centerline butterfly valves are more economical and suitable for general marine pipelines, while double offset valves are better for high pressure, high temperature, or special media.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV,

DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.

Butterfly Valve Connection Standard

Butterfly valves are widely used in industrial applications for regulating flow and are manufactured according to several connection standards. These standards ensure compatibility, safety, and reliability. Below are the common connection standards for butterfly valves:

1. Flanged Connections

Butterfly valves with flanged ends are designed to mate with standard pipe flanges. The key standards for flanged connections include:

  • ASME B16.5: Pipe Flanges and Flanged Fittings (covers sizes from ½ inch to 24 inches, pressure classes 150 to 2500).
  • EN 1092-1: Flanges and their joints for PN-designated pressure systems.
  • ISO 7005-1: Metallic flanges for general purposes.
  • JIS B2220: Japanese flange standard.

2. Wafer Type Connections

Wafer butterfly valves are designed to fit between two pipe flanges using bolts or studs.

  • They are typically compatible with flange drilling patterns as per:
    • ASME B16.5
    • EN 1092
    • ISO 7005

3. Lug Type Connections

Lug butterfly valves have threaded inserts that allow them to be bolted to a pipe flange. Standards include:

  • ASME B16.5
  • EN 1092
  • ISO 7005

4. Grooved End Connections

For quick installation and connection to grooved piping systems.

  • AWWA C606: Grooved and shouldered joints.

5. Butt-Weld Connections

Less common for butterfly valves but occasionally used in specific applications.

  • ASME B16.25: Butt-welding ends.
  • ISO 9692: Welding preparation standards.

6. Standards for Specialized Applications

  • AWWA C504: For waterworks applications, especially large-diameter valves.
  • API 609: Butterfly valves for general-purpose applications.
  • MSS SP-67: Covers butterfly valves, general-purpose and high-performance types.

Key Considerations

  • Always ensure that the valve and mating components meet the same flange drilling patterns and pressure ratings.
  • Verify that the material of construction and dimensions meet the system’s operational requirements (temperature, pressure, medium compatibility).

Let us know if you’d like details on a specific standard!

The Valve Disc Material of Concentric Type Butterfly Valve

The common valve disc materials for middle-line butterfly valves are as follows, with each material suitable for different working environments and media:

Ductile Iron: Known for its good strength, toughness, and impact resistance, ductile iron is commonly used in general industrial applications involving media such as water and gas. It is cost-effective, but its corrosion resistance is relatively poor.

304 Stainless Steel: A widely used stainless steel material, 304 offers good corrosion resistance and is suitable for less aggressive corrosive media, such as water, air, and oil.

316 Stainless Steel: Compared to 304, 316 stainless steel offers better corrosion resistance, especially in environments with more aggressive media like seawater, acidic substances, or saltwater.

C95400 Aluminum Bronze: This material provides excellent corrosion resistance, wear resistance, and mechanical strength, and is widely used in marine, shipbuilding, and chemical industries. It is suitable for highly corrosive media such as seawater and saltwater.

C95800 Aluminum Bronze: With higher strength and enhanced corrosion resistance, C95800 is particularly suitable for marine environments and applications involving corrosive media like acids and chlorides.

These materials are selected based on specific application requirements such as temperature, pressure, and the corrosiveness of the media, ensuring the most suitable valve disc material for optimal performance.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:   https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Corrosion Resistance of Marine Butterfly Valves

The corrosion resistance of marine butterfly valves is a critical factor in their selection and application, especially in marine environments. Due to the presence of salt spray, high humidity, and seawater’s corrosive nature, marine equipment requires superior corrosion-resistant properties. Below are key aspects related to the corrosion resistance of marine butterfly valves:

1. Material Selection

Material plays a crucial role in determining the corrosion resistance of marine butterfly valves. Common materials include:

  • Stainless Steel(e.g., 316, 316L): Offers excellent resistance to corrosion and is suitable for saltwater and corrosive chemical media.
  • Bronze: Resists saltwater corrosion and is commonly used in seawater piping systems.
  • Duplex Stainless Steel: Combines high strength with resistance to pitting and crevice corrosion, making it ideal for harsh marine environments.
  • Plastic Linings(e.g., PTFE, PVDF): Plastic-lined valves enhance corrosion resistance, making them suitable for handling highly corrosive media.

2. Coating and Protection

Marine butterfly valves often feature coatings or surface treatments to improve corrosion resistance:

  • Epoxy Coatings: Enhance resistance to corrosion, particularly in seawater contact areas.
  • Thermal Spray Coatings: Application of corrosion-resistant alloys (e.g., nickel-based alloys) provides additional protection.
  • Anodizing(for aluminum alloys): Improves surface hardness and resistance to oxidation.

3. Design Features

  • Seal Material Selection: Resistant materials such as EPDM or fluororubber are often used for seals to prevent failures due to corrosion.
  • Optimized Structure: Minimizing gaps and dead zones reduces the accumulation of corrosive substances.

4. Environmental Impact

  • In marine environments, salt spray and electrochemical corrosion require special attention to pitting and crevice corrosion resistance.
  • For valves submerged in seawater for extended periods, electrochemical corrosion prevention methods such as cathodic protection are essential.

5. Standards and Certifications

The materials and corrosion resistance of marine butterfly valves must comply with international or industry standards, such as:

  • ISO 15156(Standards for materials resistant to sulfide stress corrosion).
  • DNV GL, ABS, BV Certifications: International classification societies impose stringent requirements for corrosion protection in marine equipment.

6. Maintenance and Care

Regular inspection and cleaning of the valve surface, along with timely replenishment or replacement of coatings, can effectively extend the service life of marine butterfly valves.

In summary, the corrosion resistance of marine butterfly valves depends primarily on material selection, surface treatment technologies, and appropriate adaptation to specific environmental conditions. During design and selection, it is crucial to consider factors such as media properties, operating temperature, and pressure comprehensively.

Shaft Materials in Marine Valve

Shafts in marine valves are critical components that connect the actuator or handwheel to the valve’s internal components, allowing for control of fluid flow. The material selection for marine valve shafts depends on the application, operating environment, and fluid type. Common shaft materials in marine valve applications include:

1. Stainless Steels

  • Grade 316/316L:
    • High corrosion resistance, particularly against seawater and marine atmospheres.
    • Suitable for most marine applications, including those handling water, oils, and certain chemicals.
  • Duplex Stainless Steels (e.g., 2205):
    • High strength and superior corrosion resistance.
    • Excellent performance in environments with high chloride concentrations (e.g., seawater).
  • Super Duplex Stainless Steel (e.g., 2507):
    • For highly aggressive environments, including high-pressure seawater systems.

2. Bronze and Brass Alloys

  • Aluminum Bronze (e.g., C95400, C95800):
    • Excellent resistance to marine corrosion and biofouling.
    • Commonly used in seawater applications.
  • Nickel-Aluminum Bronze:
    • Provides higher strength and wear resistance.
    • Often used in valves for seawater and hydraulic systems.

3. Monel (Alloy 400)

  • High resistance to corrosion, particularly in saltwater and acidic conditions.
  • Ideal for highly corrosive environments, including marine chemical systems.

4. Hastelloy (e.g., C276, C22)

  • Exceptional resistance to chemical corrosion.
  • Used in marine environments with aggressive chemicals or extreme conditions.

5. Titanium

  • Excellent resistance to seawater corrosion and lightweight.
  • Used in specialized, high-performance applications (e.g., submarines, desalination systems).

6. Carbon Steel (with coatings)

  • Less expensive but requires protective coatings (e.g., epoxy, galvanizing) to prevent corrosion in marine environments.
  • Typically used in less demanding applications.

7. Nickel Alloys

  • Provides excellent resistance to oxidation and chloride-induced corrosion.
  • Often used in valves for extreme marine environments.

Material Selection Factors:

  • Corrosion Resistance: Seawater and chlorides are particularly aggressive.
  • Strength and Durability: High-pressure systems require stronger materials.
  • Temperature Resistance: Some applications involve elevated temperatures.
  • Chemical Compatibility: Fluids handled by the valve may demand specific material compatibility.
  • Cost: Balancing performance with budget constraints.

When designing or selecting shafts for marine valves, proper consideration of operating conditions and regulatory standards (e.g., ABS, DNV, or IMO) is crucial to ensure reliability and compliance.

Application of Concentric type Resilient Seated Butterfly Valve in Marine Vessel

Concentric type resilient seated butterfly valves are commonly used in marine vessels for several reasons:

Leakage Prevention: The resilient seat provides a tight seal, reducing the risk of leakage in critical applications. This is crucial in marine environments where leaks can lead to significant safety and operational issues.

Corrosion Resistance: These valves are often made from materials that resist corrosion, which is essential for marine applications due to the harsh saltwater environment.

Compact Design: The concentric design allows for a compact and lightweight valve, which is beneficial in the space-constrained environment of a marine vessel.

Ease of Operation: These valves generally have a simple design that makes them easy to operate, which is important for maintaining efficient and reliable operation on a vessel.

Flow Control: They provide effective flow control, which is necessary for managing various systems on a marine vessel, such as cooling systems, ballast systems, and fuel systems.

Maintenance: The design typically allows for easier maintenance and replacement, which is advantageous for keeping the vessel in good working condition.

The concentric type resilient seated butterfly valve is valued in marine applications for its reliability, resistance to corrosion, and ease of maintenance, all of which contribute to the safe and efficient operation of marine vessels.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.

We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

Classification of valve

There are many types of valves, and they can be classified in various ways.

  1. Classification by automation and actuation

Automatic Valves: These valves operate automatically relying on the medium (liquid, gas, steam, etc.) itself. Examples include safety valves, check valves, pressure reducing valves, and automatic exhaust valves.

Actuated Valves: These valves are operated manually, electrically, hydraulically, or pneumatically. Examples include butterfly valves, gate valves, and ball valves.

II.Classification by purpose and function

Shut-off Valves: Primarily used to stop or start the flow of the medium. This includes gate valves, globe valves, plug valves, ball valves, butterfly valves, etc.

Regulating Valves: Primarily used to regulate the flow, pressure, etc., of the medium. This includes control valves, throttle valves, pressure reducing valves, etc.

Check Valves: Used to prevent the backflow of the medium. This includes various types of check valves.

Diverting Valves: Used to distribute, separate, or mix the medium. This includes various types of distribution valves, three-way valves, and steam traps.

Safety Valves: Used for overpressure safety protection, releasing excess medium to prevent pressure from exceeding the specified value. Examples include safety valves.

Multi-function Valves: Used to replace two, three, or more types of valves, such as globe check valves, check ball valves, etc.

Other Special Valves: Examples include drain valves, pigging valves, etc.

III. Classification by main parameters

1, Classification by nominal diameter The nominal diameter is a rounded integer value used as a convenient reference to indicate the valve size. It is an approximate value rather than an exact measurement. The nominal diameter is marked with the letters “DN” (nominal diameter) followed by a value in millimeters. For example, a valve with a nominal diameter of 50 millimeters is marked as DN50.

  • Small diameter valves: Valves with DN≤40mm
  • Medium diameter valves: Valves with DN50-DN300mm
  • Large diameter valves: Valves with DN350-DN1200mm (4) Extra-large diameter valves: Valves with DN≥1400mm

2, Classification by pressure Nominal pressure refers to the design-specified pressure related to the mechanical strength of the pipeline components. The pressure is marked with “PN” followed by a pressure value (MPa). For example, PN1.0 indicates a valve with a nominal pressure of 1.0 MPa. (1) Vacuum valves: Valves with a working pressure lower than standard atmospheric pressure. (2) Low-pressure valves: Valves with a nominal pressure of PN<1.6 MPa. (3) Medium-pressure valves: Valves with a nominal pressure of PN 2.5–6.4 MPa. (4) High-pressure valves: Valves with a nominal pressure of PN 10.0–80.0 MPa. (5) Ultra-high-pressure valves: Valves with a nominal pressure of PN≥100 MPa.

3, Classification by working temperature of the medium (1) High-temperature valves: Valves with t > 450℃ (2) Medium-temperature valves: Valves with 120℃ ≤ t < 450℃ (3) Normal-temperature valves: Valves with -40℃ ≤ t < 120℃ (4) Low-temperature valves: Valves with -100℃ ≤ t < -40℃ (5) Ultra-low-temperature valves: Valves with t < -100℃

4, Classification by valve body material (1) Non-metallic material valves: Such as ceramic valves, fiberglass valves, plastic valves (2) Metallic material valves: Such as copper alloy valves, Monel alloy valves, cast iron valves, carbon steel valves, alloy steel valves (3) Metal body lined valves: Such as lead-lined valves, plastic-lined valves, enamel-lined valves.

5, Classification by connection method to the pipeline (1) Flange connection valves: Valves with flanges on the body, connected to the pipeline using flanges. (2) Threaded connection valves: Valves with threads on the body, connected to the pipeline using threads. (3) Welded connection valves: Valves with weld ends on the body, connected to the pipeline using welding. (4) Clamp connection valves: Valves with clamps on the body, connected to the pipeline using clamps. (5) Ferrule connection valves: Valves connected to the pipeline using ferrules.

III. Common Classification This classification method is based on principle, function, and structure and is the most commonly used classification method domestically and internationally. It generally includes gate valves, globe valves, plug valves, ball valves, butterfly valves, diaphragm valves, check valves, throttle valves, safety valves, pressure reducing valves, steam traps, and control valves.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:   https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

The Application of Concentric type Butterfly Valve in Offshore Drilling Platforms

Concentric type butterfly valves find several applications in offshore drilling platforms due to their reliability, compact design, and ease of operation. Here’s how centerline butterfly valves are used in offshore drilling platforms:

  1. Flow Control in Seawater Systems:

Concentric butterfly valves are used to control the flow of seawater for different purposes:

Cooling Systems: Regulating seawater flow for cooling heat exchangers, engines, and other equipment.

Firewater Systems: Controlling seawater flow for firefighting purposes.

General Service Water: Regulating water flow for various platform operations.

  1. Fluid Control in Drilling Operations:

Drilling Mud Systems: Controlling the flow of drilling mud during drilling operations.

Mud Mixing Systems: Regulating the flow of chemicals and additives mixed with drilling mud.

  1. Ballast Systems:

Regulating the flow of seawater into and out of ballast tanks to adjust the platform’s stability and draft.

  1. Bilge and Drainage Systems:

Managing the discharge of bilge water and other drainage fluids from the platform to maintain a safe environment.

  1. Fire Protection Systems:

Concentric butterfly valves are used in firewater deluge systems and fire hydrant systems for emergency fire suppression.

  1. Potable Water Systems:

Regulating the flow of potable water for living quarters, kitchens, and other facilities on the platform.

  1. HVAC Systems:

Controlling the flow of seawater or chilled water for heating, ventilation, and air conditioning systems.

  1. Tank Farm Operations:

Handling the flow of various liquids such as crude oil, refined products, and chemicals within the platform’s storage tank systems.

Key Advantages in Offshore Applications:

Corrosion Resistance: Materials are selected to withstand corrosive marine environments.

Space Efficiency: Compact design is suitable for installations where space is limited, which is common in offshore platforms.

Quick Operation: Rapid opening and closing for emergency shutdown situations.

Reliable Sealing: Provides tight shut-off to prevent leaks, crucial for safety and environmental protection.

Safety and Emergency Shutdown Systems:

Concentric butterfly valves are often integrated into safety systems, including emergency shutdown (ESD) systems, to quickly isolate sections of piping in case of emergencies.

Concentric type butterfly valves play a vital role in offshore drilling platforms, ensuring efficient fluid control, safety, and environmental protection. Their versatility, reliability, and space-saving design make them well-suited for various critical applications in offshore oil and gas operations. Proper selection, installation, and maintenance of these valves are essential to ensure the safe and efficient operation of offshore drilling platforms.

Tianjin Tanghai Valve Co., Ltd. is a professional marine valve manufacturer, including butterfly valve, check valve, gate /Knife gate valve. We have certificates: CE, ISO, BV, DNV foundry and products approval. Now we have our own independent R & D, manufacturing, assembly and warehousing workshops; we have professional pre-sale and after-sale technical support and perfect services. Below is our wafer butterfly valve of marine valves,if you need to check more information, please click here:https://www.tanghaivalve.com/wafer-type-butterfly-valve-th-btv-aw/.

Please contact us if you need more support, please contact us freely: info@tanghaivalve.com.We are committed to “Build a top valve enterprise; Be a reliable partner!”Friends from all over the world are welcome to visit us for evaluation, guidance, and orders!

What is the reason for the poor sealing of the valve

Where there is a pipeline, the valve is inseparable. The valve is installed on the pipeline and controls the flow of the fluid medium in the pipeline. It is an important control component. But the valve is also a wearable part. A common valve loss in our life is that the valve is not tightly sealed, resulting in leakage. So what is the reason for the poor

marine valve seat

marine valve seat

sealing of the valve?
The leakage at the packing of the valve is a part of the valve that is prone to leakage failures. The valve is not tightly sealed, and the reasons are probably as follows.
1. Sealing auxiliary structure
Under the change of temperature or sealing force, the structure of the sealing pair will change. And this change will affect and change the force between the sealing pair, so that the performance of the valve sealing is reduced. Therefore, when choosing a seal, be sure to choose a seal with elastic deformation. At the same time, pay attention to the width of the sealing surface. The reason is that the contact surfaces of the sealing pair cannot be completely matched. When the width of the sealing surface increases, the force required for sealing is increased.
2. Specific pressure of sealing surface
The specific pressure of the sealing surface affects the sealing performance of the valve and the service life of the valve. Therefore, the specific pressure of the sealing surface is also a very important factor. Under the same conditions, too high specific pressure will cause valve damage, but too low specific pressure will cause valve leakage. Therefore, we need to fully consider the appropriateness of the specific pressure when designing
3. Physical properties of the medium
The physical properties of the medium also affect the valve sealing performance. These physical properties include temperature, viscosity, and hydrophilicity of the surface, among others. The temperature change not only affects the slackness of the sealing pair and the change of the size of the parts, but also has an inseparable relationship with the viscosity of the gas. Gas viscosity increases or decreases with increasing or decreasing temperature. Therefore, in order to reduce the influence of temperature on the sealing performance of the valve, when designing the sealing pair, we should design it as a valve with thermal compensation such as an elastic valve seat. Viscosity is related to the permeability of the fluid. When under the same conditions, the higher the viscosity, the lower the permeability of the fluid. The hydrophilicity of the surface means that when there is a film on the metal surface, the film should be removed. Because of this very thin oil film, it will destroy the hydrophilicity of the surface, resulting in blockage of fluid channels.
4. The quality of the sealing pair
The quality of the sealing pair mainly means that we must check the selection, matching and manufacturing accuracy of materials. For example, the valve disc fits well with the valve seat sealing surface, which can improve the sealing performance. The characteristic of many circumferential waviness is that its labyrinth sealing performance is good.

TH Valve is a professional manufacturer of butterfly valve, gate valve, check valve, globe valve, knife gate valve, ball valve with API, JIS, DIN standard, used in Oil, Gas, Marine industry, Water supply and drainage, fire fighting, shipbuilding, water treatment and other systems, with Nominal Diameter of DN50 to DN1200, NBR/EPDM/VITON, Certificates & Approvals: DNV-GL, Lloyds, DNV, BV, API, ABS, CCS. Standards: EN 593, API609, API6D

Video of center-lined butterfly valve:

Related news/knowledge:
What are the main factors affecting valve sealing?
Factors Affecting the Operation and Use of resilient seated butterfly valves
Factors affect the sealing performance of butterfly valves
factors affecting the sealing performance of resilient butterfly valve seat

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