Understanding the key components of a concentric butterfly valve is essential for proper selection, installation, and maintenance. Each component plays a critical role in the valve's performance and longevity. Below is a detailed breakdown of the major components that make up a quality concentric butterfly valve.
The body is the main pressure-containing component of the butterfly valve. In concentric butterfly valves, the body is typically made of ductile iron (GGG40 or GGG50) for most industrial applications, though stainless steel, carbon steel, and other alloys are available for specialized applications. The body is designed to fit between pipe flanges (wafer style) or with integral flanges (lug or flanged style). Wafer-style bodies feature centering lugs for proper alignment between flanges.
The disc is the closing element that rotates to control flow. In the open position, the disc is parallel to the flow direction; in the closed position, it seals against the seat. Disc materials include: ductile iron with nylon coating (standard), SS304 (good corrosion resistance), CF8M (maximum corrosion resistance), and SS316 (food and pharmaceutical grade). The precision-machined disc edge ensures consistent sealing.
The resilient seat is the heart of the valve's sealing capability. Made from elastomeric materials such as EPDM (water/general), Buna-N (oil/fuel), or Viton/FKM (chemical/high temperature), the seat provides bubble-tight shut-off when compressed by the disc edge. In many designs, the seat is bonded directly to the body to prevent blowout and provide long service life.
The shaft connects the disc to the actuator, transmitting torque from the handle or actuator to rotate the disc. Stainless steel is the standard material. The shaft may be a single piece (through-shaft design) or split into upper and lower stems. Precision-machined shaft ends ensure proper fit with the disc and actuator mounting.
Bushings support the shaft within the body, reducing friction and wear during operation. Made from self-lubricating materials such as PTFE, bronze, or engineered polymers, they ensure smooth operation and extend the valve's service life. Proper bushing design is critical for applications with frequent cycling.
Standard on quality butterfly valves, the ISO 5211 mounting pad allows direct mounting of actuators (pneumatic, electric, or gearbox) without the need for additional brackets. The standardized bolt pattern and shaft dimensions ensure compatibility with a wide range of actuators from different manufacturers.
Butterfly valves can be operated by various means: lever handle for manual operation in smaller sizes, gearbox for easier operation of larger valves or higher pressures, pneumatic actuator for automated on-off or modulating control, and electric actuator for remote or automated applications. Each actuator type offers different torque outputs and control options.
Many butterfly valves include a visual position indicator showing whether the valve is open or closed. This is especially important for fire protection systems and applications where valve status must be quickly verified.
Every Laux Valve butterfly valve is manufactured with precision components and undergoes rigorous testing. From material certification to pressure testing, our quality assurance process ensures reliable performance in the most demanding applications.
Contact Laux Valve for more information about our complete range of concentric butterfly valves and components.
