PTFE Full Lined CF8 SS304 Body Butterfly Valve for Paper Making
Technical Specification
Design and Manufacture Standard: ASME B16.34, HG/T 3704
Face-to-face Dimension: ASME B16.10 , GB/T 12221
Flange Standard: ASME B 16.5 ,GB/T 9119 ,DIN ,JIS
Inspection and Testing: API 598, GB/T 13927
Product Specification
Body Material: WCB, ASTM A395 , CF8 ,CF8M
Lining Material: PTFE , PFA , PO ,FEP, EPDM
Nominal Diameter: 2"-80"(DN50~DN2000)
Pressure Range: Class150 , PN6 , PN10 , PN16
Connection Type: Flange ,Wafer , Lug Connection
Operation Method: Manual ,Worn gear ,Electric ,Pneumatic actuator
Primary and Secondary Shaft Sealing
The primary seal is formed by the flexible, spherically molded liner, sealing against the matching spherically machined disc hub when compressed by the resilient elastomer backup liner. The PFA liner as well as the PFA shaft over-molding extends into the valve body itself. Tight compression is maintained at the hub area and around the shaft by the resilient back-up liner combined with the flexible PFA liner, forming an independent secondary seal.
Upstream/Downstream Sealing
The dense PFA body liner is flexible, and allows the resilient elastomer back-up liner to compress the spherically molded PFA liner into the spherically machined shaft-disc with enough force to create a tight seal. This is in contrast to PTFE liners which are usually thick sinterings resulting in a stiff liner unable to give tight shut-off over a long period of time. The wide elastomer backup liner in the rests in a machined body
groove which is essential in providing tight shutoff for end of line service at full pressure. This has enabled the valve to be used for pump and
vessel isolation as well as other difficult services.
Safety Sealing
A third seal is provided by a graphite filled PTFE safety seal, which provides force against the junction of the PFA liner and PFA over-molded shaft. This seal is constantly energized by a coil spring, and self compensates for temperature changes and wear.
Flange Sealing
Provided by compression of the liner between the valve body and the flanges. An elastomer o-ring, fitted underneath the PFA liner, allows
proper flange sealing with warped flange faces or in vacuum applications.
