Overview: The document provides detailed information about Bray® Controls' Series 20/21 butterfly valves, which feature PTFE molded discs and seats. These valves are designed for use in highly corrosive environments and are suitable for various industries, including chemical, food & beverage, and pharmaceuticals.

Specifications: The valves are available in sizes ranging from 2" to 20" (50mm to 500mm). They feature a one-piece disc/stem design with PTFE molded over 17-4 ph stainless steel, ensuring maximum corrosion protection. The body is available in cast iron, 316 stainless steel, ductile iron, and aluminum, with a Nylon 11 coating for corrosion resistance.

Design Features: The Series 20 valve is a wafer version with flange locating holes, while the Series 21 is a lug version for dead-end service. The valves are compatible with international flange standards and are designed for easy installation and maintenance. The unique seat design includes an elastomer-backed PTFE seat for enhanced sealing and service life.

Materials and Temperature Range: The document outlines the materials used for the disc/stem and seat, including EPDM, Buna-N, and FKM, with temperature ranges specified for each material. PTFE-lined seats are also available for specific applications.

Pressure Ratings: The valves are tested to 110% of their full pressure rating. Bi-directional bubble-tight shut-off is achieved with pressure ratings of 150 psi for 2"-12" valves and 100 psi for PTFE molded disc and seat configurations.

Actuation and Control: Bray offers a range of actuators and control options, including pneumatic actuators (Series 92/93), solenoid valves (Series 63), and electro-pneumatic positioners (Series 6A). These components are designed for direct mounting to the valves, ensuring ease of installation and operation.

Additional Features: The document highlights the benefits of the Nylon 11 coating for corrosion protection and the modular design concept that allows for direct mounting of actuators without additional brackets or adapters.

Recommendations: For specific requirements and material selection, consultation with Bray representatives is advised. The document also notes that product design and specifications are subject to change without prior notice.