• The YFL multilayer metal seal city gas butterfly valve sealing ring of disc is composed by stainless steel plate and carbon fiber. The stainless steel sheet is primary seal and the carbon fiber is secondary seal. The double seal structure ensures reliable seal and the seal leakage grade up to ASME B16.104 VI class and ISO5208 A class;
• Compared with rubber asbestos plate and graphite, the carbon fiber is more environmental protection, more wearable, more reliable against erode, up to 200,000 times of non-failure open and close;
• The YFL bidirectional city gas butterfly valve body seat fixed by two counter rings through bolts can be replaced easily;
• Dynamically balanced sealing system makes the pressure at inlet and outlet side of disc almost balanced so that the butterfly valve will achieve reliable bidirectional seal while the operate torque is reduced effectively to almost 2/3 of normal butterfly valve;
• The unique triple offset design eliminates friction between the disc seal ring and body seat, thereby preventing wear and any consequent leakage to extend service life.

Product range:

• End connection: Flanged Wafer Lugged BW
• Size: 1"～144" (DN25～3600)
• Pressure rating: Class 150～1500 (PN2.5～PN260)
• Operation: Bare stem Lever Gearbox and handwheel Electric Pneumatic
• Body materials: Carbon steel WCB/A105 Low temperature steel LCB/LCC/LC3 High temperature steel WC6/WC9/C5/C12A Austenitic stainless steel CF8/CF8M/CF8C/CF3/CF3M/CG8M Super austenitic stainless steel 254SMO A351 CK-3MCuN Duplex stainless steel UNS S31803/UNS S32205/N08904 Super duplex stainless steel UNS S32750/UNS S32760 Titanium alloy B368 gr.C-2 Hastelloy C276 Monel alloy A494 M-35-1 Aluminum bronze B148 C95800 Inconel 625 Incoloy 825 Alloy 20 CN7M etc.
• Disc seal ring: SS304 SS316 with flexible graphite or carbon fiber
• Body seat materials: SS304 SS316 Stellite etc.
• Stem materials: SS420 17-4PH SS304 SS316 etc.
• Disc materials: WCB CF8 CF8M 904L C95800 etc.

Technical standards:

• Design: ASME B16.34 DIN 3840
• Face to Face: API 609 ASME B16.10 ISO5752
• BW ends: ASME B16.25 ASME B31.8 EN12627
• Flanged ends: ASME B16.5 ASME B16.47 EN1092
• ISO top flange: ISO5211
• Materials: NACE MR 01-75
• Wall thickness: ASME B16.34
• Test and inspection: API 598
• Fireproof test: API 607 API 6FA
• Pressure and temperature rating: API609 ASME B16.34