Product Overview
Professionally designed to suit ASME standard flanges and PN16 flanges
Durable Polyester Coated Valve for Harsh Environments
The 31H series lug style resilient seated butterfly valves are drilled and mounted to ASME 125/150 and PN16 flange standards. This rugged high-strength one-piece stem design features an efficient internal disc-to-stem connection. The 31H series valves provide primary and secondary seals between the disc and seat as well as between the stem and seat, ensuring complete encapsulation of pipe media for zero external leakage.
Technical Specifications
| Item | Parameter |
|---|---|
| Size Range | NPS 2 to 20 / DN 50 to 500 |
| Body Material | Cast Iron, Ductile Iron |
| Temperature Range | -20°F to 250°F (-29°C to 121°C) |
| Stem Material | 416 Stainless Steel |
| Maximum Allowable Operating Pressure | 250 psi (17.2 Bar) |
| Seat Material | Bonded EPDM, Bonded BUNA-N |
| Seat Class | Bidirectional Bubble-tight |
| Disc Material | Nylon 11 Coated Ductile Iron, Nickel Aluminum Bronze, Stainless Steel |
| Body Type | Lug |
| Testing Standard | MSS SP-61, API 598, EN 12266-1, ISO 5208 |
| Certification | ABS, ATEX, CRN, DNV, NSF 61/372, PED, PE(S)R, SIL, TR CU |
| Face-to-Face | MSS SP-67, API 609 Category A, EN 558 20 Series |
| Flange Drilling | ASME B16.1 Class 125, ASME B16.5 Class 150, EN 1092 PN16 |
| Application | High Pressure, HVAC, Dead-End Service |
Features and Benefits
A Stem Retention Assembly
The stem is retained in the body through a unique stainless steel Spirolox® retaining ring, a thrust washer, and two C-rings. These components are standard in brass and available in stainless steel on request.
B Stem Bushing
Non-corrosive heavy-duty acetal bushing absorbs actuator side thrust.
C Stem Packing
Dual “U” cup seal design is self-adjusting and provides a strong bidirectional seal.
D Primary and Secondary Seals
These stem packings prevent pipe media from contacting the stem or body. The primary seal is achieved through interference fit with the molded seat flats on the disc hub. The secondary seal is achieved through a larger stem diameter than the seat stem hole diameter.
E Body
One-piece lug style. Features polyester fiber coating for excellent corrosion resistance. Nylon 11 coating is also available.
F Seat
Bray’s tongue and groove bonded seat design completely isolates the fluid media from the body. The seat also features a molded O-ring, eliminating the need for flange gaskets.
G Disc
Castings are spherically machined and hand-polished to provide bubble-tight sealing with minimum torque and longer seat life. Bray resilient Nylon 11 coating is standard.
H Stem
Precision double “D” disc-to-stem connection drives the disc without the use of screws or pins. This precision tolerance double “D” form connection is a unique Bray valve design. Simply remove the stem from the disc to disassemble the Bray stem.