Tag Archive for: Ductile iron

A concentric butterfly valve with a carbon steel body is a common type of valve used in industrial applications for regulating or isolating the flow of fluids. The concentric design means that the valve disc and stem are aligned on the same axis, making it suitable for low-to-moderate pressure applications. Below are the key features of this type of valve:

1. Concentric Design (Centerlined)

Shaft and Disc Alignment: The shaft (or stem) is centrally located in the valve body, and the disc rotates on the same axis as the shaft. This allows for even pressure distribution on the valve seat.

No Offsets: Unlike offset butterfly valves, concentric valves have no displacement of the shaft relative to the seat and disc, making them simpler and easier to maintain.

2. Carbon Steel Body

Material Strength: Carbon steel is strong and durable, suitable for applications that involve moderate pressure and temperature.

Corrosion Resistance: Carbon steel provides moderate corrosion resistance but may require external coatings (such as epoxy) or internal linings to protect against aggressive chemicals or moisture.

Temperature Tolerance: Carbon steel can withstand relatively high temperatures (up to approximately 425°C or 800°F), making it appropriate for steam, oil, or gas applications.

Cost-Effective: Carbon steel is less expensive compared to stainless steel, making it a cost-effective solution for many industrial applications.

3. Soft Seat

Elastomeric Seat: Concentric butterfly valves typically use soft seats made from elastomeric materials like EPDM, Nitrile (Buna-N), or PTFE. These materials provide a bubble-tight seal, especially in low-pressure applications.

Replaceable Seat: The seat is often replaceable, which allows for easy maintenance and longer valve life.

Leakage Protection: Soft seats offer good sealing performance and can achieve zero leakage (Class VI shutoff).

4. Disc Design

Material: The disc is typically made of stainless steel, ductile iron, or other alloys to provide enhanced corrosion resistance in different environments.

Low Flow Resistance: When the valve is fully open, the disc is parallel to the flow of the fluid, resulting in minimal flow resistance and a low-pressure drop.

Tight Shutoff: The disc is designed to provide tight shutoff, making the valve ideal for applications where leakage prevention is critical.

5. Bi-Directional Flow

The concentric butterfly valve is capable of controlling the flow of fluids in both directions, enhancing its versatility in piping systems.

6. Low Torque Requirement

The concentric design requires low torque for operation. This makes the valve easier to operate manually and reduces the power needed for actuation when automated.

7. Compact and Lightweight

Space-Saving: Butterfly valves are compact and lightweight compared to other valve types like gate or globe valves. This makes installation easier and reduces the weight on piping systems, especially in larger diameter applications.

8. Wafer or Lug Type Connection

Wafer Type: Designed to fit between two flanges using long bolts that pass through both flanges and the valve body.

Lug Type: Features threaded inserts, allowing the valve to be installed between flanges and secured with bolts on each side. This enables removal of downstream piping without disturbing the upstream piping.

9. Operation Options

Manual Operation: Operated using a handwheel or lever for simple, on/off control.

Automated Operation: The valve can be equipped with pneumatic, electric, or hydraulic actuators for remote or automated control.

10. Applications

Suitable for low-to-moderate pressure and temperature applications in industries like:Water Treatment: Used in pipelines for water distribution and wastewater treatment.

HVAC Systems: Applied in heating, ventilation, and air conditioning systems for flow regulation.

Oil & Gas: Used in gas transmission pipelines, oil refineries, and other industrial applications involving non-corrosive fluids.

Chemical Processing: Ideal for handling non-corrosive chemicals, light acids, and alkaline solutions.

Power Generation: Common in cooling water and steam lines.

11. Easy Maintenance

The simple design of the concentric butterfly valve with fewer moving parts allows for easy maintenance. The seat and disc are generally replaceable, reducing downtime and operational costs.

12. Pressure and Temperature Range

Pressure Rating: Typically suitable for low to medium pressure applications (up to 300 PSI or higher depending on the design).

Temperature Range: Can handle a wide range of temperatures, especially when paired with appropriate seat materials. However, soft-seated valves are more suitable for moderate temperature ranges.

13. Cost-Effective Solution

Concentric butterfly valves with carbon steel bodies offer an economical solution for applications where high durability, moderate pressure handling, and cost-efficiency are required, making them popular for general-purpose use in industries like water treatment, HVAC, and oil and gas.

Summary of Key Benefits:

Cost-Effective: Carbon steel is affordable, and concentric valves are simpler in design.

Durable: Withstands moderate temperature and pressure applications.

Compact: Saves space and reduces the overall weight of the piping system.

Easy to Maintain: Simple design with replaceable parts.

Versatile: Suitable for water, gas, steam, and light chemical handling.

 

These features make concentric butterfly valves with carbon steel bodies ideal for a variety of applications that require reliability, cost-efficiency, and easy maintenance.

 

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 maintenance of a concentric (centered) butterfly valve in ships is essential to ensure the valve’s optimal performance and longevity, especially in harsh marine environments. Concentric butterfly valves have the disc located in the center of the valve body, with a resilient seat that helps to seal the valve when closed. These valves are commonly used for fluid control in various ship systems, including seawater cooling, ballast systems, and bilge systems. Here’s a guide to maintaining a concentric butterfly valve on ships:

1. Visual Inspection

External Inspection:Regularly check the valve for any visible signs of corrosion, wear, or damage, especially around the body, stem, and handle or actuator.

Marine environments are prone to corrosion due to saltwater, so special attention should be given to areas exposed to seawater.

Inspect for any salt deposits, marine growth, or other debris that may accumulate around the valve body and flanges.

Seal Inspection:Inspect the valve’s seat (usually made of rubber or elastomer) for wear or damage. The seal is crucial for the valve’s tight closure.

Check for cracks, deformities, or wear in the seal that could lead to leakage. The seal is one of the most critical parts, and its condition directly affects valve performance.

2. Regular Cleaning

Valve Cleaning:Clean the exterior and interior of the valve regularly to remove any buildup of marine organisms, rust, silt, or debris that may impair its function.

Use approved marine cleaning agents that do not damage the valve’s materials. After cleaning, thoroughly rinse the valve with freshwater to remove any residual chemicals.

Seal and Disc Cleaning:Gently clean the valve’s disc and seat to remove any deposits. Marine organisms, like barnacles or algae, can settle on the disc, potentially impacting valve closure.

3. Lubrication

Stem and Moving Parts:

Lubricate the stem and other moving parts of the valve as per the manufacturer’s recommendations. Marine-grade lubricants should be used to prevent corrosion and ensure smooth operation.

Avoid over-lubricating, as excess lubricant can attract dirt or debris.

Actuator Lubrication (for automated valves):

If the valve is equipped with an actuator (pneumatic, hydraulic, or electric), ensure that the actuator’s moving parts are adequately lubricated. Regularly check actuator connections to ensure they are secure and functioning smoothly.

4. Operational Testing

Open and Close Testing:Periodically operate the valve by fully opening and closing it to ensure the disc moves freely. A valve that isn’t operated regularly may become stiff or difficult to operate due to corrosion, buildup, or seal hardening.

Ensure that there are no sticking points, and check the valve handle or actuator for any issues.

Leakage Testing:Perform a hydrostatic or pneumatic test at operating pressure to detect any leaks. If leakage is found, inspect the seat, seal, and disc for damage.

For valves under critical operation (e.g., seawater intake or discharge), this test should be part of routine inspections.

5. Seal Replacement

Seal and Seat Maintenance:

The resilient seat is a key component that provides a bubble-tight seal in a concentric butterfly valve. Over time, the seat can wear out or become damaged due to constant use or exposure to chemicals, requiring replacement.

Replace the valve seat if you notice signs of cracking, deformation, or excessive wear that could compromise its sealing ability.

Stem Seals:

Inspect the stem seals (o-rings or gaskets) for wear. If these seals fail, it could lead to leakage around the stem area.

6. Corrosion Protection

Protective Coating:

Apply protective coatings, like marine-grade anti-corrosive paints, to the external parts of the valve that are exposed to saltwater or humid environments.

If the valve is made from a material prone to rust (such as certain grades of cast iron), extra attention should be given to keeping the body protected from corrosion.

Material Compatibility:

Ensure that the valve material (body and disc) is suitable for the specific fluid or gas being handled. Corrosion-resistant materials like stainless steel or bronze should be used for seawater applications.

7. Actuator and Control System Maintenance

Actuator Inspection:

For automatic valves, inspect the actuator system regularly. Check for signs of wear, corrosion, or malfunction in the actuator.

Ensure the actuator’s control signals are accurate, and the valve opens and closes fully when triggered.

Control System Calibration:

If the valve is part of an automated control system, periodically calibrate the system to ensure it operates at the correct parameters (e.g., pressure or flow settings).

8. Bolts and Flange Check

Tightness of Flange Bolts:Periodically check the tightness of the bolts securing the valve to the pipe flanges. Marine vibrations can loosen these bolts over time.

Use the manufacturer-recommended torque settings when tightening bolts to avoid over-tightening or damaging the valve body.

9. Gasket Inspection

Flange Gasket:Check the condition of flange gaskets between the valve and pipe flanges. If leaks are detected, the gasket may need to be replaced.

Gaskets exposed to high pressure, temperature, or aggressive fluids might degrade faster and require more frequent replacement.

Summary of Key Maintenance Practices:

Regular inspection: Visual and operational checks for corrosion, leaks, and damage.

Cleaning: Routine cleaning of valve components to remove marine growth and deposits.

Lubrication: Ensure moving parts are lubricated using marine-grade products.

Seal and gasket maintenance: Inspect and replace the valve seat, stem seals, and flange gaskets as needed.

Operational tests: Open and close the valve to ensure smooth operation.

Corrosion protection: Apply anti-corrosion coatings and ensure material compatibility with seawater.

Maintenance Schedule:

Weekly: Visual inspections, operational testing, and cleaning of external surfaces.

Monthly: Internal cleaning, actuator system checks, and lubrication.

Annually: Comprehensive inspections, including seal, gasket, and bolt checks; perform leakage tests and replace worn-out components.

Maintaining concentric butterfly valves on ships is crucial for ensuring the reliability of fluid systems, preventing leaks, and extending the valve’s service life.

 

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!

When installing a wafer-type dual plate check valve in a pipeline, specific precautions must be observed due to its compact design and the way it interfaces with the piping system. Here are the key precautions:

1. Correct Orientation:

Ensure that the flow direction matches the arrow indicated on the valve body. Installing the valve in the incorrect orientation can prevent it from functioning correctly and may cause damage.

2. Centering the Valve:

Properly center the wafer-type valve between the flanges to prevent misalignment. Misalignment can lead to uneven sealing, potential leaks, and difficulty in operation.

3. Gasket Placement:

Ensure the gaskets are correctly positioned and compatible with the valve and flange materials. They should be centered and not protruding into the valve flow area, as this could obstruct the valve plates and affect operation.

4. Avoid Over-Tightening Bolts:

Tighten the flange bolts in a crisscross pattern to apply even pressure across the valve. Over-tightening can warp the valve body or damage the gaskets, leading to leaks or operational issues.

5. Pipeline Support:

The pipeline should be properly supported on either side of the valve to avoid placing excessive weight or stress on the valve, which could affect its alignment and functionality.

6. Check for Obstructions:

Inspect the pipeline for any debris or foreign objects before installation. Ensure that the valve plates can open and close freely without any obstructions.

7. Correct Valve Sizing:

Verify that the valve is correctly sized for the specific flow rate and pressure conditions of the system. Using a valve that is too large or too small can lead to poor performance or damage.

8. Even Flange Face Contact:

Ensure that the flange faces are clean, smooth, and parallel to ensure proper sealing. Uneven flange faces can cause leaks or improper seating of the valve.

9. Avoiding Thermal and Mechanical Stress:

Avoid installing the valve in areas of the pipeline where it might be subjected to excessive mechanical stress, vibrations, or thermal expansion, which could lead to valve failure.

10. Hydrostatic Testing:

After installation, conduct a hydrostatic test with the valve fully closed to check for leaks. Make sure the pressure applied during testing does not exceed the valve’s pressure rating.

11. Proper Tools and Handling:

Use appropriate tools for handling and installing the wafer-type valve. Avoid using excessive force or improper tools, which could damage the valve body or internal components.

12. Accessibility for Maintenance:

Install the valve in a location that allows for easy access for inspection and maintenance. Wafer-type valves often require periodic checks to ensure they are functioning correctly.

13. Temperature and Pressure Considerations:

Ensure the valve materials are suitable for the operating temperature and pressure of the system. Avoid subjecting the valve to conditions that exceed its design specifications.

14. Lubrication (if applicable):

Some wafer-type valves may require lubrication of the hinge pin or other components. Follow the manufacturer’s recommendations for any required lubrication.

By carefully following these precautions, you can ensure a secure, leak-free installation and reliable operation of the wafer-type dual plate check valve in your pipeline system.

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!