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Lug Concentric Type Butterfly Valve with Rubber Seated(tanghai valve)

A lug concentric type butterfly valve with rubber seated refers to a specific configuration of a butterfly valve commonly used in various industries, including marine applications. Let’s break down its features, considerations for selection, and how it’s typically used:


  1. Concentric Design: Like other concentric butterfly valves, this type features a design where the stem passes through the center of the disc, ensuring a uniform seal around the circumference. This design minimizes turbulence and pressure drop while providing efficient flow control.
  2. Lug Style: The valve body has lugs (also known as ears or tabs) on the valve’s periphery, allowing it to be bolted directly between flanges in the pipeline. This design provides easy installation and removal without needing to disconnect the entire pipeline.
  3. Rubber Seating: The valve has rubber or elastomeric seating, typically made from materials like EPDM or NBR, which provide excellent sealing properties. Rubber seats offer resilience, chemical resistance, and longevity, making them suitable for various fluids and operating conditions.
  4. Bidirectional Sealing: Similar to other concentric butterfly valves, this type can seal bidirectionally, allowing it to be installed in either direction without affecting its performance.
  5. Manual or Actuated Operation: Lug concentric butterfly valves are available in both manual and actuated configurations. Manual valves are operated by hand, while actuated valves can be controlled remotely using pneumatic, electric, or hydraulic actuators for automated flow control.

Selection Considerations:

  1. Size and Pressure Rating: Choose a valve size and pressure rating suitable for the intended application and operating conditions. Consider factors such as flow rate, system pressure, and compatibility with existing piping.
  2. Material Construction: Select valve materials compatible with the fluid being handled and the environmental conditions. Common materials include stainless steel, carbon steel, ductile iron, and various alloys.
  3. Seat Material: Consider the type of seat material (e.g., EPDM, NBR, PTFE) based on the fluid properties (e.g., temperature, viscosity, chemical compatibility) and sealing requirements.
  4. Operation Type: Decide whether manual or actuated operation is preferred based on the level of automation required, accessibility, and control system integration.
  5. Standards Compliance: Ensure the selected valve complies with relevant industry standards and certifications for quality, performance, and safety, such as ANSI, API, ISO, and marine classification societies’ requirements.


  1. Installation: Properly install the lug concentric butterfly valve between flanges using appropriate gaskets and fasteners according to manufacturer specifications and industry standards.
  2. Operation: Operate the valve manually or remotely using the designated controls, following established procedures for opening, closing, and adjusting the flow as needed.
  3. Maintenance: Implement a regular maintenance schedule to inspect, clean, lubricate, and replace components as necessary to ensure optimal performance and longevity.
  4. Monitoring: Periodically monitor the valve’s operation and condition for signs of leakage, wear, or malfunction, and take corrective action as required to prevent downtime or safety hazards.
  5. Emergency Response: Establish protocols for responding to valve failures, leaks, or other emergencies, including shutdown procedures, isolation measures, and contingency plans to mitigate risks and minimize disruptions.

By considering these factors and following best practices for selection, installation, and maintenance, lug concentric butterfly valves with rubber seating can effectively control flow and provide reliable performance in marine applications and other industrial settings.