Industrial concentric plastic butterfly valves are flow control devices used in various industrial applications where corrosion resistance, lightweight construction, and cost-effectiveness are essential. Here’s an overview of these valves:

1. Design: Concentric plastic butterfly valves feature a circular body made of thermoplastic materials such as PVC (polyvinyl chloride), CPVC (chlorinated polyvinyl chloride), PVDF (polyvinylidene fluoride), or PP (polypropylene). The valve design incorporates a disc positioned in the center of the flow stream when fully open. This concentric design minimizes pressure drop across the valve and ensures a tight seal when closed.

2. Seat Design: The seat of a concentric plastic butterfly valve is typically made of resilient elastomeric materials such as EPDM (ethylene propylene diene monomer) or Viton. When the valve is closed, the disc presses against the seat to form a tight seal, preventing leakage.

3. Materials: Plastic butterfly valves are made from thermoplastic materials chosen for their corrosion resistance, lightweight construction, and affordability. The choice of material depends on factors such as the chemical compatibility of the fluid being handled and the operating temperature range.

4. Actuation: Concentric plastic butterfly valves can be operated manually using a hand lever or gear operator, or they can be automated using pneumatic or electric actuators. Actuators allow for remote control and automation of the valve operation, which is essential in industrial processes where precise flow control is required.

5. Applications:

   • Water and Wastewater Treatment: Plastic butterfly valves are commonly used in water and wastewater treatment plants for regulating the flow of water, chemicals, and slurry.
   • Chemical Processing: They find applications in chemical processing plants for handling corrosive chemicals and aggressive fluids.
   • Aquaculture and Aquariums: Plastic butterfly valves are used in aquaculture systems and aquariums for controlling the flow of water and other fluids.
   • Swimming Pools: They are employed in swimming pool systems for regulating the flow of water and chemicals.

6. Advantages:

   • Corrosion Resistance: Plastic butterfly valves offer excellent corrosion resistance, particularly when used with compatible thermoplastic materials for the specific application.
   • Lightweight Construction: Plastic valves are lightweight, making them easy to handle and install compared to metal valves.
   • Cost-Effectiveness: Plastic butterfly valves are often more affordable than valves made from metal alloys, making them a cost-effective solution for many industrial applications.
   • Easy Maintenance: Plastic valves are generally easy to clean and maintain, requiring minimal maintenance over their lifespan.

7. Disadvantages:

   • Temperature Limitations: Plastic butterfly valves may have temperature limitations compared to metal valves, particularly at high temperatures where thermoplastic materials may soften or deform.
   • Pressure Limitations: Plastic valves may have pressure limitations compared to metal valves, particularly in high-pressure applications where metal valves are preferred for their strength and durability.
   • Chemical Compatibility: While plastic valves offer excellent corrosion resistance, their chemical compatibility must be carefully considered for compatibility with the specific fluids being handled.

Overall, industrial concentric plastic butterfly valves offer a lightweight, corrosion-resistant, and cost-effective solution for flow control in a wide range of industrial applications, particularly where corrosion resistance and affordability are critical requirements.